The Journal of Thoracic and Cardiovascular Surgery - Articles in Press

Results after mitral valve replacement with mechanical prostheses in young children - Corrected Proof

2010-03-12

Objective: We examined outcomes after mitral valve replacement in children younger than 8 years.Methods: Medical records of patients who underwent mitral valve replacement from 1990 to 2006 were reviewed. Competing-risks methodology determined time-related prevalence and associated factors for death, repeated valve replacement, and survival without reoperation.Results: In total, 79 patients, median age 24 months (40 days–8 years) underwent 91 mitral valve replacements (10 had repeated procedures). Underlying pathology was congenital heart disease in 95% of cases. Forty-six patients (58%) had undergone previous operations. Operative mortality was 18%, 30% for those 2-years old and younger and 6% for those older than 2 years. Competing-risks analysis showed that 10 years after initial mitral valve replacement, 40% of patients had died without repeated replacement, 20% had undergone a second replacement, and 40% remained alive without further replacement. Factors associated with death included higher prosthesis size/patient weight ratio (P < .0001) and longer crossclamp time (P < .0001). Second replacement 6 ± 4 years after initial replacement was necessary for 10 survivors. At second replacement, larger prostheses were implanted (mean 24 mm vs 19 mm initially). Repeated MVR was associated with younger age at surgery (p = .006). Permanent pacemaker implantation was eventually needed by 11% of hospital survivors.Conclusions: Mortality and repeated valve replacement are common after mitral valve replacement in children younger than 8 years, especially younger patients with significantly oversized valves. At valve reoperation, larger prostheses could be implanted, suggesting continued annular growth.

Prophylactic ventral cardiac denervation: Does it reduce incidence of atrial fibrillation after coronary artery bypass grafting? - Corrected Proof

2010-03-12

Objective: This study assessed the prophylactic effect of ventral cardiac denervation on reducing atrial fibrillation after coronary artery bypass grafting.Methods: This randomized prospective study recruited 220 adult patients (aged 42–79 years) who were scheduled to undergo coronary artery bypass grafting. Of these patients, 110 underwent ventral cardiac denervation in addition to coronary artery bypass grafting and 110 underwent only coronary artery bypass grafting. The demographic, intraoperative, and postoperative factors comprising atrial fibrillation were compared between the 2 groups. In addition, the predictive factors of atrial fibrillation in all 220 cases were assessed.Results: The mean age and the distribution of gender, body mass index, diabetes mellitus, chronic obstructive pulmonary disease, hypertension, hypercholesterolemia, and left main disease were not significantly different between the 2 groups. Atrial fibrillation incidence was significantly different between the groups (P=.025), with an incidence of 20.9% in the ventral cardiac denervation group and 10% in the control group. Atrial fibrillation occurred in 34 of the 220 patients, and ventral cardiac denervation was considered as a variable to evaluate its possible role in the prevention of postoperative atrial fibrillation. Our multivariate analysis showed age (P=.002; odds ratio,1.098; confidence interval, 1.034–1.165) and ventral cardiac denervation (P=.044; odds ratio,2.32; confidence interval, 1022–5.298) as the predictive factors of atrial fibrillation after coronary artery bypass grafting.Conclusion: Given the surprising results of the present study demonstrating that ventral cardiac denervation is a predictive factor of atrial fibrillation after coronary artery bypass grafting, ventral cardiac denervation should not be routinely considered for the prevention of atrial fibrillation after coronary artery bypass grafting.

Cryoprobe biopsy increases the diagnostic yield in endobronchial tumor lesions - Corrected Proof

2010-03-12

Objective: Forceps biopsy is the standard method to obtain specimens in endoscopically visible lesions. It is common to combine forceps biopsy with cytology methods to increase the diagnostic yield. Although the flexible cryoprobe has been established for bronchoscopic interventions in malignant stenosis, the obtained biopsies, called “cryobiopsies,” have not been investigated in a large cohort of patients. The aim of this feasibility study was to prospectively evaluate the diagnostic yield and safety of cryobiopsy and forceps biopsy.Methods: During a 6-year period, 296 patients with visible endoluminal tumor lesions were included in the study at the bronchoscopy unit of a university hospital. In the first consecutively conducted 55 cases, both techniques, forceps biopsy and cryobiopsy, were applied simultaneously. Pathologic and quantitative image analyses were performed to evaluate the size and quality of the obtained specimens. We evaluated the safety and diagnostic yield to describe the feasibility of cryobiopsy.Results: Comparative analysis of the first conducted and randomly assigned 55 cases revealed a significantly higher diagnostic yield for cryobiopsy compared with forceps biopsy (89.1% vs 65.5%, P < .05). In this cohort, quantitative image analysis showed significantly larger biopsies regarding size and artifact-free tissue sections for cryobiopsy compared with forceps biopsy (P < .0001). The overall diagnostic yield of cryobiopsy was 89.5%. Mild bleeding occurred in 11 cases (3.7%), moderate bleeding occurred in 3 cases (1.0%), and severe bleeding occurred in 1 case (0.3%).Conclusion: Cryobiopsy is safe and increases the diagnostic yield in endobronchial tumor lesions. The method also is feasible under routine conditions.

Transapical mitral valved stent implantation: A survival series in swine - Corrected Proof

2010-03-12

Objective: To assess short-term survival after transcatheter mitral valve replacement using a unique mitral valved stent design and anchoring system.Methods: The new nitinol self-expandable valved stent houses a trileaflet glutaraldehyde-preserved bioprosthesis and contains atrial and ventricular fixation systems. Eight pigs underwent transesophageal echocardiogram-guided transapical mitral valved stent implantation through a lower mini-sternotomy. Intracardiac pressure gradients were estimated by transesophageal echocardiogram.Results: The mean mitral annulus size was 24.6 ± 1.4 mm, and the valved stent size was 26.0 ± 2.6 mm. The average mean transvalvular gradient across the valved stent immediately after deployment, at 6 hours, and after 1 week remained low. The gradient across the neighboring left ventricular outflow tract was not affected. Average animal survival was 7.3 days (8 hours to 29 days). Animals that died before 1 week (n = 4) were found at necropsy to have valved stent malpositioning. Animals that survived 1 week or more had accurate deployment and only trace post-deployment paravalvular leak. The causes of death in this latter group were endocarditis (n = 1), failure of atrial fixation (n = 2), and failure of ventricular fixation (n = 1). There was no valved stent embolization in any of the animals.Conclusion: Adequate function and effective anchoring of the new mitral valved stent allowed for short-term animal survival after transapical mitral valved stent implantation.

Left ventricular remodeling early after correction of mitral regurgitation: Maintenance of stroke volume with decreased systolic indexes - Corrected Proof

2010-03-12

Objective: Mitral valve repair for mitral regurgitation is followed by left ventricle adjustment to new preload and afterload. We evaluated left ventricular geometry and function immediately after mitral valve repair for degenerative prolapse.Methods: We prospectively studied 25 patients undergoing mitral valve repair; 15 patients undergoing a coronary artery bypass graft served as controls to determine the impact of cardiopulmonary bypass and cardioplegic arrest on left ventricular function. Intraoperative transesophageal echocardiography was conducted after sternotomy before initiation of cardiopulmonary bypass and after termination of cardiopulmonary bypass and protamine infusion. Simultaneous pulmonary catheter data ensured that the images were obtained under similar hemodynamic conditions.Results: Immediately after mitral valve repair, left ventricular fractional area change decreased significantly from 65% ± 7% to 52% ± 8% (P < .001). Left ventricular end-diastolic area decreased minimally (21.3 ± 5.3 cm2 vs 19.4 ± 4.5 cm2; P = .005), whereas left ventricular end-systolic area increased significantly (7.5 ± 2.3 cm2 vs 9.3 ± 2.5 cm2; P < .001). Notably, forward stroke volume (thermodilution) remained similar (63 ± 24 mL vs 66 ± 19 mL; P = .5). No significant difference was found in controls between pre- cardiopulmonary bypass and post-cardiopulmonary bypass fractional area change (54% ± 12% vs 57% ± 10%; P = .19), left ventricular end-diastolic area (16.6 ± 6.2 cm2 vs 15.7 ± 5.0 cm2; P = .32), and stroke volume (72 ± 29 mL vs 65 ± 19 mL; P = .15); they had a slight decrease in left ventricular end-systolic area (7.9 ± 4.4 cm2 vs 6.9 ± 3.2 cm2; P = .03).Conclusion: Early after correction of mitral regurgitation, left ventricular fractional area change decreases significantly, primarily as the result of a larger end-systolic dimension. This may be a compensatory mechanism to prevent augmentation of forward stroke volume after mitral valve repair.

Orthotopic vascularized right lung transplantation in the mouse - Corrected Proof

2010-03-10

Objectives: Orthotopic left lung transplantation in the mouse, as recently developed by our laboratory, represents a physiologic model for studies in transplantation biology. However, because of the limited overall respiratory contribution of the murine left lung, left lung transplant recipients remain healthy despite immune-mediated graft necrosis. We sought to develop a lung transplantation model in which animal survival depends on graft function.Methods: Orthotopic vascularized right lung transplantations using cuff techniques were performed in syngeneic and allogeneic strain combinations. Grafts were assessed histologically or functionally by measuring arterial blood gases from 7 to 28 days after transplantation. In a parallel set of experiments, syngeneic and immunosuppressed allogeneic hosts underwent a left pneumonectomy 2 weeks after right lung transplantation, with assessment of graft function 1 week later.Results: We performed 40 right lung transplantations, with a survival rate of 87.5%. Syngeneic grafts remain free of inflammation as far as 28 days after transplantation. On day 7, arterial oxygen levels in syngeneic recipients (481 ± 90 mm Hg) are equivalent to those in naive mice (503 ± 59 mm Hg) after left hilar occlusion. Alternatively, allogeneic grafts develop histologic evidence of acute rejection, and arterial oxygen levels are significantly decreased after left hilar clamping (53.3 ± 10.3 mm Hg). Both syngeneic and immunosuppressed allogeneic right lung recipients tolerate a left pneumonectomy.Conclusions: Right lung transplantation followed by left pneumonectomy represents the first survival model of vascularized lung transplantation in the mouse and will therefore allow for the design of novel studies in experimental lung transplantation.

Ambulatory extracorporeal membrane oxygenation: A new approach for bridge-to-lung transplantation - Corrected Proof

Jose P. Garcia, Aldo Iacono, Zachary N. Kon, Bartley P. Griffith — 2010-03-10

Extracorporeal membrane oxygenation (ECMO) for severe respiratory failure can be used to maintain adequate gas exchange but precludes ambulation and may lead to further deconditioning. We present a case of ambulatory ECMO for severe respiratory failure using a dual-lumen single cannula system.

The option of taking down the Fontan circulation: The Melbourne experience - Corrected Proof

Ajay J. Iyengar, Christian P. Brizard, Igor E. Konstantinov, Yves d' Udekem — 2010-03-10

In recent years, dramatic early failure of the Fontan circulation has become exceedingly rare, although there are occasional deaths in patients with large ongoing chest drain losses. Fontan takedown to a prior palliative state has been described to allow successful survival of these patients, but only limited information exists on the early and long-term results of this rescue procedure.

Cellular phenotype transformation occurs during thoracic aortic aneurysm development - Corrected Proof

2010-03-10

Objective: Thoracic aortic aneurysms result from dysregulated remodeling of the vascular extracellular matrix, which may occur as a result of altered resident cellular function. The present study tested the hypothesis that aortic fibroblasts undergo a stable change in cellular phenotype during thoracic aortic aneurysm formation.Methods: Primary murine aortic fibroblasts were isolated from normal and thoracic aortic aneurysm-induced aortas (4 weeks post induction with 0.5mol/L CaCl2 15minutes) by the outgrowth method. Normal and thoracic aortic aneurysm cultures were examined using a focused polymerase chain reaction array to determine fibroblast-specific changes in gene expression in the absence and presence of biological stimulation (endothelin-1, phorbol-12-myristate-13-acetate, angiotensin-II). The relative expression of 38 genes, normalized to 4 housekeeping genes, was determined, and genes displaying a minimum 2-fold increase/decrease or genes with significantly different normalized cycle threshold values were considered to have altered expression.Results: At steady state, thoracic aortic aneurysm fibroblasts revealed elevated expression of several matrix metalloproteinases (Mmp2, Mmp11, Mmp14), collagen genes/elastin (Col1a1, Col1a2, Col3a1, Eln), and other matrix proteins, as well as decreased expression of Mmp3, Timp3, and Ltbp1. Moreover, gene expression profiles in thoracic aortic aneurysm fibroblasts were different than normal fibroblasts after equivalent biological stimuli.Conclusion: This study demonstrated for the first time that isolated primary aortic fibroblasts from thoracic aortic aneurysm-induced mice possess a unique and stable gene expression profile, and when challenged with biological stimuli, induce a transcriptional response that is different from normal aortic fibroblasts. Together, these data suggest that aortic fibroblasts undergo a stable phenotypic change during thoracic aortic aneurysm development, which may drive the enhancement of extracellular matrix proteolysis in thoracic aortic aneurysm progression.

Effectiveness of combination of losartan potassium and doxycycline versus single-drug treatments in the secondary prevention of thoracic aortic aneurysm in Marfan syndrome - Corrected Proof

2010-03-02

Objective: Losartan potassium (INN losartan), an antihypertensive drug, has been shown to prevent thoracic aortic aneurysm in Marfan syndrome through the inhibition of transforming growth factor β. Recently we reported that doxycycline, a nonspecific inhibitor of matrix metalloproteinases 2 and 9, normalized aortic vasomotor function and suppressed aneurysm growth. We hypothesized that a combination of losartan potassium and doxycycline would offer better secondary prevention treatment than would single-drug therapy to manage thoracic aortic aneurysm.Methods: A well-characterized mouse model of Marfan syndrome (Fbn1C1039G/+) was used. At 4 months of age, when aneurysm had established, mice (n = 15/group) were given doxycycline alone (0.24 g/L), losartan potassium alone (0.6 g/L), or combined (0.12-g/L doxycycline and 0.3-g/L losartan potassium) in drinking water. Littermate Fbn1+/+ mice served as control. Thoracic aortas at 6 and 9 months were studied.Results: At 9 months, aortic diameter in untreated group was increased by 40% relative to control. Losartan potassium or doxycycline reduced aortic diameter by 10% to 16% versus untreated aortas. Losartan potassium and doxycycline combined completely prevented thoracic aortic aneurysm and improved elastic fiber organization, also downregulating matrix metalloproteinases 2 and 9 and transforming growth factor β and normalizing aortic contractile and relaxation functions to control values.Conclusions: Neither losartan potassium nor doxycycline alone completely restored vascular integrity and cell function when given during delayed treatment, indicating the importance of timed pharmacologic intervention. Combined, however, they synergistically offered better aneurysm-suppressing effects than did single-drug medication in the secondary prevention of thoracic aortic aneurysm.

A novel running annuloplasty suture technique for robotically assisted mitral valve repair - Corrected Proof

Tomislav Mihaljevic, Craig M. Jarrett, A. Marc Gillinov, Eugene H. Blackstone — 2010-03-02

Longer operative times necessary for robotic mitral valve (MV) repair have in part slowed its adoption. A significant portion of operative time is dedicated to placement of the annuloplasty ring, which is usually anchored with individual mattress sutures that require time-consuming instrument tying. We have developed an alternative technique using running annuloplasty sutures that requires fewer steps than conventional techniques and could reduce operative times. We sought to compare the safety and effectiveness of this novel running annuloplasty suture technique with the conventional interrupted annuloplasty suture technique.

Pioglitazone preserves vein graft integrity in a rat aortic interposition model - Corrected Proof

Zhi Chen, Tomomi Hasegawa, Akiko Tanaka, Yutaka Okita, Kenji Okada — 2010-03-02

Objective: Improvement of vein graft patency may be highly beneficial in coronary artery bypass grafting, but graft degeneration is considered to be one of the main pathophysiologic causes for vein graft failure. Because peroxisome proliferator-activated receptor-γ activator pioglitazone was recently reported to possess pleiotropic protective effects on various organs and tissues, we conducted experiments to test the hypothesis that pioglitazone could prevent graft degeneration, leading to the preservation of vein graft integrity.Methods: In a rat aortic interposition model with autologous femoral vein, pioglitazone (3 mg/kg/d) or vehicle (normal saline) was given to rats by gastric gavage once per day beginning 3 days before surgery and ending 8 weeks after surgery. Vein graft degeneration and remodeling were assessed at 24 hours, 7 days, 8 weeks, and 6 months after surgery.Results: At 24 hours, pioglitazone significantly reduced endothelial desquamation, reactive oxygen species generation, myeloperoxidase activity, and lipid peroxidation in vein grafts. At 7 days, mRNA expression and gelatinolytic activity of matrix metalloproteinase-2 and 9 in vein grafts were significantly suppressed by pioglitazone treatment. Immunofluorescent staining showed that pioglitazone enhanced peroxisome proliferator-activated receptor-γ expression in vein grafts at 8 weeks, especially in their intimal side. At 6 months, pioglitazone treatment prevented graft dilation (52.3% ± 3.1% vs 90.7% ± 9.9%, P = .0041) and neointimal hyperplasia (14.6% ± 1.3% vs 29.9% ± 2.9%, P = .0008), and increased graft flow velocity ratio (0.86 ± 0.03 vs 0.59 ± 0.04, P < .0001), compared with vehicle treatment.Conclusion: Pioglitazone prevents graft degeneration under arterial pressure stress and preserves the vein graft integrity in a rat aortic interposition model.

Off-pump bilateral internal thoracic artery grafting in patients with left main disease - Corrected Proof

2010-03-02

Objective: This study assessed the safety and efficacy of off-pump bilateral internal thoracic artery grafting in patients with left main disease.Methods: We reviewed the records of 768 patients who underwent off-pump bilateral internal thoracic artery grafting between September 2004 and June 2009. Bilateral internal thoracic artery grafts were used for the left coronary system in all patients, of whom 268 had left main disease and 500 did not. We compared operative and postoperative variables and early and 1-year angiographic patency rates of the bilateral internal thoracic artery between the 2 groups.Results: The perioperative mortality and incidence of postoperative complications were not significantly different between groups. In patients without left main disease, the left and right internal thoracic arteries were used for the left anterior descending artery in 87.4% and 12.2% of patients, respectively. In patients with left main disease, the left and right internal thoracic arteries were used for the left anterior descending artery in 70.5% and 29.1% of patients, respectively. In patients with left main disease, the patency rates for the left and right internal thoracic arteries at 1-year postoperative follow-up were 97.0% and 93.2%, respectively. In patients without left main disease, the patency rates for the left and right internal thoracic arteries at 1-year follow-up were 97.6% and 91.6%, respectively. The patency rates of the left and right internal thoracic arteries did not differ significantly in patients with or without left main disease (P = .9803 and P = .7205 in left and right internal thoracic arteries, respectively).Conclusion: Off-pump bilateral internal thoracic artery grafting was safe and effective in patients with left main disease. The patency rates of both grafts were comparable to those of patients without left main disease.

Role of age in acute type A aortic dissection outcome: Report from the International Registry of Acute Aortic Dissection (IRAD) - Corrected Proof

2010-02-22

Objective: The increasing life expectancy of the population will likely be accompanied by a rise in the incidence of acute type A aortic dissection. However, because of an increased risk of cardiac surgery in an elderly population, it is important to define when, if at all, the risks of aortic repair outweigh the risk of death from unoperated type A aortic dissection.Methods: We analyzed 936 patients with type A aortic dissection enrolled in the International Registry of Acute Aortic Dissection from 1996 to 2004. Patients with type A aortic dissection were categorized according to patient age by decade and by surgical versus medical management, and outcomes of both management types were investigated in the different age groups.Results: The rate of surgical aortic repair decreased progressively with age, whereas surgical mortality significantly increased with age. Age 70 years or more was an independent predictor for mortality (38.2% vs 26.0%; P < .0001, odds ratio 1.73). The in-hospital mortality rate was significantly lower after surgical management compared with medical management until the age of 80 years. For patients aged 80 to 90 years, the in-hospital mortality appeared to be lower after surgical management (37.9% vs 55.2%; P = .188); however, this failed to reach clinical significance owing to the limited patient number in this age group.Conclusions: Although the surgical mortality significantly increased with increased age, surgical management was still associated with significantly lower in-hospital mortality rates compared with medical management until the age of 80 years. Surgery may decrease the in-hospital mortality rate for octogenarians with type A aortic dissection and might be considered in all patients with type A aortic dissection regardless of age.

Pattern of aortic aneurysms in an African country - Corrected Proof

Julius A. Ogeng'o, Beda O. Olabu, Justus P. Kilonzi — 2010-02-22

Objective: We sought to describe the regional, age, and sex distribution; diagnosis; treatment; and outcome of aortic aneurysms in a Kenyan population.Methods: This was a retrospective study at Kenyatta National Hospital, Kenya. Records of black African patients whose final diagnosis was aortic aneurysm over the period from January 1998 to December 2007 were examined. Frequencies and means are presented in tables and bar charts.Results: Two hundred sixty-four (92 male and 172 female patients) files were analyzed. The mean age was 56.15 years. Two hundred twenty-three (84.5%) aneurysms occurred in the abdominal aorta, followed by the descending aorta (7.5%), ascending aorta, (3.8%) and arch (1.9%). In 2.3% of cases, both the abdominal and thoracic aortas were affected. The male/female ratio was 1:1.9. Pain with swelling or a pulsatile mass was the predominant feature. More than 50% of the cases were diagnosed by means of ultrasonographic analysis. Sixty-one (23.1%) aneurysms were ruptured, and of this group, 44 (72.1%) patients died. Successful open surgical repair was done in 157 (59.5%) patients. Hypertension was a comorbidity in 137 (51.9%) cases.Conclusion: Aortic aneurysms in Kenya show abdominal segment and female predominance, occur 10 to 15 years earlier than in white populations, and carry high mortality from rupture. Hypertension was the leading associated risk factor. Ultrasonographic screening and control of blood pressure might be useful preventive measures.

Reduction in postsurgical adhesion formation after cardiac surgery by application of N,O-carboxymethyl chitosan - Corrected Proof

Juan Zhou, J. Michael Lee, Patricia Jiang, Susan Henderson, Timothy D.G. Lee — 2010-02-22

Objective: The study objectives were to assess the efficacy of N,O carboxymethyl chitosan film in reducing postsurgical adhesion in a rabbit cardiac injury model and to confirm the efficacy of N,O carboxymethyl chitosan gel and film in reducing postsurgical adhesion formation in a pig cardiac injury model.Methods: (1) Rabbit cardiac injury model: Cardiac injury was generated by abrading the anterior surface of the heart and desiccation with oxygen. N,O carboxymethyl chitosan solution and film were administered to the injured surface. (2) Pig cardiac injury model: Cardiac injury was generated as described above. N,O carboxymethyl chitosan solution and gel (or film) were administered to the injured surface. The severity and area of adhesion between the heart and the sternum were evaluated at 14 days postcardiac surgery.Results: (1) Rabbits treated with N,O carboxymethyl chitosan film plus solution showed significantly reduced severity and area of adhesion formation. (2) Both N,O carboxymethyl chitosan gel plus solution and N,O carboxymethyl chitosan film plus solution significantly reduced adhesion formation in the pig model.Conclusion: Application of N,O carboxymethyl chitosan products significantly reduces severity of postsurgical adhesion formation after cardiac surgery in the rabbit and pig models. N,O carboxymethyl chitosan products may act as a biophysical barrier.

Video-assisted thoracic surgery versus open lobectomy for lung cancer: A secondary analysis of data from the American College of Surgeons Oncology Group Z0030 Randomized Clinical Trial - Corrected Proof

2010-02-22

Objective: Video-assisted thoracoscopic lobectomy remains controversial. We compared outcomes from participants in a randomized study comparing lymph node sampling versus dissection for early-stage lung cancer who underwent either video-assisted thoracoscopic or open lobectomy.Methods: Data from 964 participants in the American College of Surgeons Oncology Group Z0030 trial were used to construct propensity scores for video-assisted thoracoscopic versus open lobectomy (based on age, gender, histology, performance status, tumor location, and T1 vs T2). Propensity scores were used to estimate the adjusted risks of short-term outcomes of surgery. Patients were classified into 5 equal-sized groups and compared using conditional logistic regression or repeated measures analysis of variance.Results: A total of 752 patients (66 video-assisted and 686 open procedures) were analyzed on the basis of propensity score stratification. Median operative time was shorter for video-assisted thoracoscopic lobectomy (video-assisted thoracoscopy 117.5 minutes vs open 171.5 minutes; P < .001). Median total number of lymph nodes retrieved (dissection group only) was similar (video-assisted thoracoscopy 15 nodes vs open 19 nodes; P = .147), as were instances of R1/R2 resection (video-assisted thoracoscopy 0% vs open 2.3%; P = .368). Patients undergoing video-assisted thoracoscopic lobectomy had less atelectasis requiring bronchoscopy (0% vs 6.3%, P = .035), fewer chest tubes draining greater than 7 days (1.5% vs 10.8%; P = .029), and shorter median length of stay (5 days vs 7 days; P < .001). Operative mortality was similar (video-assisted thoracoscopy 0% vs open 1.6%, P = 1.0).Conclusion: Patients undergoing video-assisted lobectomy had fewer respiratory complications and shorter length of stay. These data suggest video-assisted thoracoscopic lobectomy is safe in patients with resectable lung cancer. Longer follow-up is needed to determine the oncologic equivalency of video-assisted versus open lobectomy.

Discussion - Corrected Proof

2010-02-22

Dr John D. Mitchell, MD (Denver, Colo). The ACOSOG Z30 study was a randomized multi-institutional prospective trial designed to assess the relative merits of mediastinal lymph node dissection versus sampling in patients with early-stage lung cancer, both in terms of the perioperative morbidity of the 2 procedures and the long-term oncologic outcomes. The first has been reported, as Walter said, and we await the data regarding recurrence and survival.

Bochdalek diaphragmatic hernia masquerading as tension hydropneumothorax in an adult - Corrected Proof

2010-02-22

A 25-year-old man presented with upper abdominal pain and respiratory distress lasting for 4 days. On initial evaluation, he was having mild tenderness in the epigastrium and reduced air entry on the left side of the chest. A succussion splash was heard on the left side of chest. A chest x-ray showed tension hydropneumothorax on the left side (). In view of respiratory distress, an intercostal drain was inserted on the left side of the chest. The chest tube did not drain pleural fluid. The next day, a 64-slice computed tomography scan of the chest was done that showed a Bochdalek hernia with the stomach, colon, and left lobe of the liver in the thorax. The patient underwent operation, and at laparotomy the Bochdalek hernia was seen on the left side of the diaphragm posteriorly. The stomach, splenic flexure of colon, and left lobe of the liver were seen passing through the hernia into the thorax. The stomach had ischemic changes that reverted back to normal on reperfusion and application of hot packs. The stomach, colon, and liver were reduced, and the hernia was repaired. The patient's condition improved clinically, and the chest x-ray showed a well-expanded left lung. The patient was discharged on the seventh day.

A case of Sjögren's syndrome leading to mitral and aortic valve replacement - Corrected Proof

Kevin Bridge, Robert Saeid Farivar — 2010-02-22

A 62-year-old woman presented with dyspnea on exertion, and an echocardiogram demonstrated an ejection fraction of 55% to 60%, severe mitral regurgitation, and moderate aortic regurgitation. The patient had rheumatic disease as a child, and her valve failure was presumed to be due to rheumatic disease sequelae. She previously had an axillary lymph node biopsy for adenopathy at an outside hospital and was thought to have Castleman's disease. At the University of Iowa Heart and Vascular Center, she underwent aortic and mitral valve replacement through a full sternotomy and bicaval cannulation. The aortic valve was replaced with a 21-mm Magna ThermaFix Edwards bovine pericardial valve (Edward Lifesciences, Irvine, Calif). The mitral valve was replaced with a 29-mm St Jude Epic porcine valve (St Jude Medical Inc, St Paul, Minn). Intraoperatively, the pericardium was found to be inflamed and adherent to the aorta and right ventricle. The native aortic valve was trileaflet, and both valves were rubbery in consistency with significant nodules present. The leaflets were friable. No calcification was found on the mitral annulus. The mitral valve was not repairable.

Polymer self-locking clips for vascular control during minimally invasive pulmonary lobectomies - Corrected Proof

Marco Lucchi, Leonardo Duranti, Franca Melfi, Alfredo Mussi — 2010-02-22

Control and division of the hilar vessels is a crucial step in performing minimally invasive pulmonary lobectomy safely and efficiently. Hem-o-lok clips (Teleflex Medical, Inc, Reading, Pa) were first introduced in 1999 and have already been used and validated for laparoscopic nephrectomy, as well as other urologic and general surgery procedures. They are nonabsorbable polymer clips characterized by a lock-engagement feature, which ensures the closure of the clip itself, and teeth within the jaws, designed to prevent slippage. Hem-o-lok clips come in 4 sizes. Their curved shape helps the surgeon to surround the vessels. Three applicator tools have been developed: one for open surgery, one for endoscopic surgery, and another for robotic surgery. Applicators for open surgery come in 2 forms: angular or straight. The endoscopic device is only straight, whereas the robotic device is assembled on the robotic EndoWrist instrument (Intuitive Surgical, Inc, Mountain View, Calif) and has 7 degrees of mobility.

Evaluation of a new left atrial retractor for minimally invasive mitral valve surgery - Corrected Proof

Olivier Jegaden, Thomas Sassard, Abdel Shafy, Mouhcine Madani, Fadi Farhat — 2010-02-19

Exposure of the mitral valve is a key success factor in minimally invasive mitral valve surgery (MIMVS) and a prerequisite for successful mitral valve repair. We report the concept of a new left atrial retractor (MitraXs, St Jude Medical Inc, Minneapolis, Minn) dedicated to MIMVS. The effectiveness of the device was evaluated in a prospective series.

Two cases of aneurysm of the anterior mitral valve leaflet associated with transcatheter aortic valve endocarditis: A mere coincidence? - Corrected Proof

2010-02-18

The incidence of transcatheter aortic valve endocarditis (TAVE) is currently unknown. To the best of our knowledge, 2 clinical case reports of TAVE have been published (1 Edwards SAPIEN [Edwards Lifesciences, Irvine, Calif] and 1 Medtronic CoreValve ReValving System [Medtronic CV, Luxembourg Sarl]). Interestingly, both cases were associated with aneurysm and perforation of the anterior mitral valve leaflet—a link that has not been previously reported. We briefly review the clinical presentations of these cases and discuss the possible implications of endocarditis in the context of transcatheter aortic valve implantation.

Comparison of fractional flow reserve of composite Y-grafts with saphenous vein or right internal thoracic arteries - Corrected Proof

2010-02-18

Background: Composite Y-grafts, using the left internal thoracic artery as the inflow, allow a more efficient use of conduits without the need to touch a diseased ascending aorta. Among other conduits, the saphenous vein graft may be an alternative to the radial artery in elderly patients.Patients and Methods: We evaluated the hemodynamic characteristics of 17 composite Y-grafts made with the left internal thoracic artery anastomosed to the left anterior descending coronary artery in all cases and with either the free right internal thoracic artery (RITA group, n = 10) or a saphenous vein graft (SVG group, n = 7) implanted proximally to the left internal thoracic artery and distally to the circumflex territory 6 months after the operation.Results: At baseline, the pressure gradient measured with a 0.014-inch pressure wire was minimal between the aorta and the internal thoracic artery stem (2 ± 1 mm Hg), the internal thoracic artery and left anterior descending (4 ± 2 mm Hg), the internal thoracic artery and left circumflex (3 ± 1 mm Hg), and the saphenous vein graft and left circumflex (2 ± 2 mm Hg). During hyperemia induced by adenosine, the pressure gradient increased significantly to 6 ± 2 mm Hg in the internal thoracic artery stem, 9 ± 4 mm Hg in the internal thoracic artery and left anterior descending artery, 9 ± 3 mm Hg in the internal thoracic artery and left circumflex, and 7 ± 4 mm Hg in the saphenous vein graft and left circumflex. Fractional flow reserve was 0.94 ± 0.02 in internal thoracic artery stem, 0.90 ± 0.04 mm Hg in the internal thoracic artery and left anterior descending, 0.91 ± 0.03 mm Hg in the internal thoracic artery and left circumflex, and 0.92 ± 0.06 mm Hg in the saphenous vein graft and left circumflex. No difference between the two types of composite Y-grafts was observed for pressure gradients or fractional flow reserve measured in internal thoracic artery stem or in distal branches.Conclusion: Composite Y-grafts with saphenous vein or right internal thoracic arteries allow similar and adequate reperfusion of the left system with minimal resistance to maximal flow and an even distribution of flow in both distal branches.

In vitro functional comparison of therapeutically relevant human vasculogenic progenitor cells used for cardiac cell therapy - Corrected Proof

2010-02-18

Objective: In cardiac cell therapy almost every cell type tested experimentally has yielded some benefit. However, there is a lack of studies directly comparing the function of various stem/progenitor cell populations. This study describes the expansion of peripheral blood CD133+ cells and compares their functional properties with those of other commonly used human progenitor cell populations.Methods: CD133+ cells were generated from the CD133− fraction of peripheral blood, either serially (pooled–derived) or after 14 days of culture (derived). Their phenotypic, migratory, and vasculogenic properties were compared with those of 4 commonly used progenitor cell populations in vitro.Results: Serial expansion resulted in an 11-fold increase in the number of CD133+ cells. The proportion of derived CD133+ cells collected between 0 and 8 days also expressing CD34 and vascular endothelial growth factor receptor 2 was similar (approximately 60%, P=.41). Adherent, 4-day cultured endothelial progenitor cells demonstrated enhanced migration compared with each of the other 5 cell populations (all P ≤ .002). The migration of derived CD133+ progenitors was enhanced by coculture with CD133− cells or their supernatant (P < .05). In vitro vasculogenesis assays revealed that derived and pooled–derived CD133+ cells had superior vasculogenic potential compared with other progenitor populations (P ≤ .03).Conclusions: A novel source of expandable CD133+ cells can be generated from the CD133− fraction of peripheral blood. The CD133 phenotypic marker translates into the cell being vasculogenically more potent in vitro, which could be beneficial to inducing vasculogenesis in the ischemic heart. Furthermore, intercellular interactions appear important for improving the therapeutic efficacy of cell transplantation.

Center variation and outcomes associated with delayed sternal closure after stage 1 palliation for hypoplastic left heart syndrome - Corrected Proof

2010-02-18

Objective: There is debate whether primary or delayed sternal closure is the best strategy after stage 1 palliation for hypoplastic left heart syndrome. We describe center variation in delayed sternal closure after stage 1 palliation and associated outcomes.Methods: Society of Thoracic Surgeons Congenital Database participants performing stage 1 palliation for hypoplastic left heart syndrome from 2000 to 2007 were included. We examined center variation in delayed sternal closure and compared in-hospital mortality, prolonged length of stay (length of stay > 6 weeks), and postoperative infection in centers with low (≤25% of cases), middle (26%–74% of cases), and high (≥75% of cases) delayed sternal closure use, adjusting for patient and center factors.Results: There were 1283 patients (45 centers) included. Median age at surgery was 6 days (interquartile range, 4–9 days), and median weight at surgery was 3.2 kg (interquartile range, 2.8–3.5 kg); 59% were male. Delayed sternal closure was used in 74% of cases (range, 3%–100% of cases/center). In centers with high (n = 23) and middle (n = 17) versus low (n = 5) delayed sternal closure use, there was a greater proportion of patients with prolonged length of stay and infection, and a trend toward increased in-hospital mortality in unadjusted analysis. In multivariable analysis, there was no difference in mortality. Centers with high and middle delayed sternal closure use had prolonged length of stay (odds ratio, 2.83; 95% confidence interval, 1.46–5.47; P = .002 and odds ratio, 2.23; confidence interval, 1.17–4.26; P = .02, respectively) and more infection (odds ratio, 2.34; confidence interval, 1.20–4.57; P = .01 and odds ratio, 2.37; confidence interval, 1.36–4.16; P = .003, respectively).Conclusion: Use of delayed sternal closure after stage 1 palliation varies widely. These observational data suggest that more frequent use of delayed sternal closure is associated with longer length of stay and higher postoperative infection rates. Further evaluation of the risks and benefits of delayed sternal closure in the management of these complex infants is necessary.

The relationship between perioperative temperature and adverse outcomes after off-pump coronary artery bypass graft surgery - Corrected Proof

2010-02-18

Objective: The study objective was to determine predictors of hypothermia and hyperthermia, and the impact of hypothermia and hyperthermia on postoperative outcomes for off-pump coronary artery bypass grafting.Methods: We performed a retrospective study of 2294 patients who underwent off-pump coronary artery bypass grafting in New York in 2007. Patients were classified as moderately to severely hypothermic (≤34.5°C), mildly hypothermic (34.6°C–35.9°C), or mildly hyperthermic (37.5°C–38.8°C) after leaving the operating room. Significant independent predictors of these temperature states and the independent impact of each of these states on in-hospital mortality and complications were identified.Results: A total of 37.7% of patients were mildly hypothermic, 9.0% of patients were moderately to severely hypothermic, and 5.6% of patients were mildly hyperthermic. Significant independent predictors for postoperative hypothermia included older age, female gender, lower body surface area, congestive heart failure, higher ventricular function, non-Hispanic ethnicity, single/double-vessel disease, low postoperative hematocrit, previous cardiac surgery, race other than white or black, and organ transplant. Patients with moderate to severe hypothermia had significantly higher risk-adjusted in-hospital mortality than patients with normothermia (adjusted odds ratio 3.00; 95% confidence interval, 1.11–8.08). Patients with mild hyperthermia also had significantly higher mortality (adjusted odds ratio 5.04; 95% confidence interval,1.18–21.55). Patients with either mild or moderate to severe hypothermia had significantly higher rates of respiratory failure and unplanned operations, and patients with mild hyperthermia had a significantly higher rate of respiratory failure than normothermic patients.Conclusion: It is important to maintain normal postsurgical core temperatures in patients who have undergone cardiac surgery to minimize or avoid death and complications.

Off-pump versus on-pump coronary artery bypass grafting: A systematic review and meta-analysis of propensity score analyses - Corrected Proof

Oliver Kuss, Benita von Salviati, Jochen Börgermann — 2010-02-18

Objective: Despite numerous randomized and nonrandomized trials on off- and on-pump coronary artery bypass grafting, it remains open which method is superior. Patient selection and small sample sizes limit the evidence from randomized trials; lack of randomization limits the evidence from nonrandomized trials. Propensity score analyses are expected to improve on at least some of these problems. We aimed to systematically review all propensity score analyses comparing off- and on-pump coronary artery bypass grafting.Methods: Propensity score analyses comparing off- and on-pump surgery were identified from 8 bibliographic databases, citation tracking, and a free web search. Two independent reviewers abstracted data on 11 binary short-term outcomes.Results: A total of 35 of 58 initially retrieved propensity score analyses were included, accounting for a total of 123,137 patients. The estimated overall odds ratio was less than 1 for all outcomes, favoring off-pump surgery. This benefit was statistically significant for mortality (odds ratio, 0.69; 95% confidence interval, 0.60–0.75), stroke, renal failure, red blood cell transfusion (P < .0001), wound infection (P < .001), prolonged ventilation (P < .01), inotropic support (P = .02), and intraaortic balloon pump support (P = .05). The odds ratios for myocardial infarction, atrial fibrillation, and reoperation for bleeding were not significant.Conclusion: Our systematic review and meta-analysis of propensity score analyses finds off-pump surgery superior to on-pump surgery in all of the assessed short-term outcomes. This advantage was statistically significant and clinically relevant for most outcomes, especially for mortality, the most valid criterion. These results agree with previous systematic reviews of randomized and nonrandomized trials.

Predictors of low cardiac output syndrome after isolated mitral valve surgery - Corrected Proof

2010-02-12

Background: Low cardiac output syndrome is defined as the need for a postoperative intra-aortic balloon pump or inotropic support for longer than 30 minutes in the intensive care unit. Mitral valve surgery is increasingly being performed in high-risk patients who might require mechanical circulatory support for low cardiac output syndrome. Therefore the aim of this study was to identify the preoperative predictors of low cardiac output syndrome after mitral valve surgery.Methods: We conducted a retrospective review of data prospectively entered into an institutional database. Between 1990 and February 2008, 3039 patients underwent isolated mitral valve surgery with or without coronary bypass surgery. The independent predictors of low cardiac output syndrome and operative mortality were determined by means of stepwise logistic regression analysis.Results: The overall prevalence of low cardiac output syndrome was 7%. The independent predictors of low cardiac output syndrome were urgency of the operation (odds ratio, 2.9), earlier year of operation (odds ratio, 2.4), left ventricular ejection fraction of less than 40% (odds ratio, 2.1), New York Heart Association class IV (odds ratio, 2), body surface area of 1.7 m2 or less (odds ratio, 1.6), ischemic mitral valve pathology (odds ratio, 1.6), and cardiopulmonary bypass time (odds ratio, 1.02). The operative mortality was higher in patients with low cardiac output syndrome (30% vs 1.3%, P < .001). Overall operative mortality was 3.4%. The independent predictors of mortality were urgency of the operation (odds ratio, 7.1), renal failure (odds ratio, 4.3), nonuse of polytetrafluoroethylene sutures (Gore-Tex; W. L. Gore & Associates, Inc, Austin, Tex; odds ratio, 2.1), any reoperative surgical intervention (odds ratio, 1.8), increasing age (odds ratio, 1.03), and cardiopulmonary bypass time (odds ratio, 1.02).Conclusions: Low cardiac output syndrome is associated with significantly increased morbidity and mortality. Novel strategies to preserve renal function, optimization of pre-existing heart failure symptoms, and use of artificial polytetrafluoroethylene sutures might reduce the incidence of low cardiac output syndrome and lead to improved results after mitral valve surgery.

Cardiac dysfunction induced by experimental myocardial infarction impairs the host defense response to bacterial infection in mice because of reduced phagocytosis of Kupffer cells - Corrected Proof

2010-02-08

Objective: This study was undertaken to investigate the effects of cardiac dysfunction induced by experimental myocardial infarction on the host defense response to bacterial infection and the role of Kupffer cells in mediating this response.Methods: Myocardial infarction was induced in C57BL/6 mice by ligation of the left anterior descending coronary artery. Mice were challenged with Escherichia coli intravenously 1, 5, and 14 days after myocardial infarction or sham operation. Thereafter, the cytokine production and the function of their Kupffer cells were assessed.Results: Mice with myocardial infarction showed remarkable cardiac dysfunction and had a significantly lower survival than sham mice after bacterial challenge at 5 days after surgery; bacterial challenge at 1 or 14 days after surgery resulted in no difference in survival between myocardial infarction and sham mice. The phagocytic activity of Kupffer cells, assessed by fluorescein isothiocyanate microspheres, remarkably decreased in mice with myocardial infarction 5 days after surgery. Serum peaks of tumor necrosis factor and interferon-γ after bacterial challenge were also suppressed in mice with myocardial infarction at 5 days. Production of these cytokines and immunoglobulin-M from liver mononuclear cells was also impaired in mice with myocardial infarction. Enhancement of the phagocytic activity of Kupffer cells by C-reactive protein significantly improved survival after infection in mice with myocardial infarction, although neither interleukin-18 nor immunoglobulin-M treatment improved survival.Conclusion: Cardiac dysfunction induced by myocardial infarction renders mice susceptible to bacterial infection and increases mortality because of a reduced ability of Kupffer cells to clear infectious bacteria. C-reactive protein-enhanced phagocytic activity of Kupffer cells may improve the poor prognosis after bacterial infection in mice with myocardial infarction.

The effect of transplant center volume on survival after heart transplantation: A multicenter study - Corrected Proof

Jeffrey H. Shuhaiber, Jeff Moore, David B. Dyke — 2010-02-08

Objective: Few studies have examined the association between procedural volume and clinical outcomes in heart transplantation. This retrospective study was performed on a contemporary cohort of heart transplant recipients to better elucidate the effect of transplant center volume on 1-year mortality.Methods: Data from the Scientific Registry of Transplant Recipients were used to analyze the relationship between transplant center volume and short-term survival. Center volume designation (very low, low, medium, and high) was assigned on the basis of quartiles with approximately equal numbers of patients per group. Survival differences were explored using Cox proportional hazards modeling to adjust for differences in variables between volume groups and to determine variables associated with 1-year mortality.Results: Between January 1, 1999, and May 31, 2005, 13,230 heart transplantations were performed at 147 transplant centers in the United States. Although most recipient and donor characteristics were similar across quartiles, larger volume centers were more likely to perform transplantations in older candidates and accept organs from older donors with longer cold ischemia times. A statistically significant relationship between transplant center volume and 1-year mortality was observed. Compared with the reference group (very low volume), the hazard ratios for the low, medium, and high-volume quartiles were 0.71, 0.64, and 0.56, respectively (P < .001 for each group compared with the reference).Conclusion: There was a significant association between transplant center volume and 1-year survival. Patients who undergo cardiac transplantation at very low-volume centers are at higher risk for early mortality than those who undergo transplantation in higher-volume centers.

The relationship of plasma transfusion from female and male donors with outcome after cardiac surgery - Corrected Proof

2010-02-08

Objective: Pulmonary dysfunction is common in transfused patients recovering from heart surgery. Plasma transfusion from female donors has been linked with rare catastrophic lung injury, but its relationship with outcome after cardiac surgery is poorly understood. We examined whether plasma donor gender is related to postcardiac surgery pulmonary dysfunction and death or prolonged hospitalization.Methods: In this retrospective case-control study, cardiac surgery candidates who received plasma perioperatively from only female donors were compared with male-only recipients who were matched for the number of units transfused and surgery date.Results: In a dataset of 2157 recipients, there were no blood bank–reported complications, but escalating plasma transfusion was associated with increased 30-day mortality (odds ratio, 1.52 per unit; P = .0001). From the 1069 recipients receiving plasma exclusively from female or male donors, 390 matched pairs were identified. Recipients of female compared with male donor plasma had a lower incidence of pulmonary dysfunction (5.9% vs 10.8%; P = .01) and death or hospitalization more than 10 days (9% vs 16.4%; P = .002) but similar long-term survivals.Conclusion: Escalating plasma transfusion was associated with 30-day mortality, but female donor plasma recipients had less pulmonary dysfunction and fewer poor outcomes compared with male-only recipients. Although our retrospective study findings neither support nor refute a strategic policy to exclude female donor plasma to reduce catastrophic transfusion-related acute lung injury, they raise concern that such a policy may have unanticipated effects on outcome in patients undergoing cardiac surgery and highlight a need for additional studies in this and other patient groups.

Normokalemic adenosine–lidocaine cardioplegia: Importance of maintaining a polarized myocardium for optimal arrest and reanimation - Corrected Proof

Kathryn L. Sloots, Geoffrey P. Dobson — 2010-02-04

Objective: Depolarizing potassium cardioplegia does not afford optimal cardioprotection in pediatric or adult patients requiring complicated operative procedures. Polarizing adenosine–lidocaine cardioplegia has been shown to be cardioprotective without hyperkalemia. Our aim was to examine the effects of changing extracellular potassium levels in adenosine–lidocaine cardioplegia on arrest and reanimation properties.Methods: Isolated–perfused rat hearts (n = 96) were arrested at 32°C to 33°C for 1 or 2 hours with intermittent 200 μmol/L adenosine and 500 μmol/L lidocaine in modified Krebs–Henseleit buffer with 0.1, 3.0, 5.9, 10, and 16 mmol/L potassium or with 16 or 25 mmol/L potassium in Krebs–Henseleit buffer (n = 8 for each group). Membrane potentials were estimated in the arrested ventricular myocardium (n = 42), and recovery function was measured in working mode during 60 minutes' reperfusion.Results: Arrest was interrupted by breakout beats in the adenosine–lidocaine hypokalemic (0.1 and 3 mmol/L potassium) and non–adenosine–lidocaine hyperkalemic (16 and 25 mmol/L potassium) groups. The membrane potentials for the non–adenosine–lidocaine 16 and 25 mmol/L potassium groups were −51 and −39 mV, and those for the adenosine–lidocaine groups (0.1, 3.0, 5.9, 10, and 16 mmol/L potassium) were −183, −94, −75, −65, and −49 mV, respectively. After 1 hour of arrest, coronary vascular resistance increased linearly in adenosine–lidocaine cardioplegia with increasing potassium levels (5.9, 10, and 16 mmol/L), and the slope increased more than 2-fold after 2 hours. Nearly 40% of hearts in the adenosine–lidocaine (0.1 mmol/L potassium) and non–adenosine–lidocaine 25 mmol/L potassium groups failed to recover after 1 hour arrest. After 2 hours, hearts in the polarizing (5.9 mmol/L potassium) adenosine–lidocaine group increased coronary vascular resistance by only 30% and spontaneously recovered 107% heart rate, 92% systolic pressure, 81% aortic flow, and 113% coronary flow (all metrics returned 85% to 100% at 15 minutes) with no reperfusion arrhythmias. In contrast, hearts in the adenosine–lidocaine (3, 10, and 16 mmol/L potassium) groups were all slow to recover (15% to 40% return at 15 minutes) and experienced arrhythmias. Increasing potassium levels in adenosine–lidocaine cardioplegia from 5.9 to 16 mmol/L resulted in a 67% loss of left ventricular contractility.Conclusions: Polarizing adenosine–lidocaine cardioplegia (5.9 mmol/L potassium) administered intermittently at 33°C provides superior arrest and reanimation profiles under normokalemic conditions when the myocardial cell membrane potential is close to its resting state.

Right ventricular failure in patients with the HeartMate II continuous-flow left ventricular assist device: Incidence, risk factors, and effect on outcomes - Corrected Proof

2010-02-04

Objective: The aim of this study was to evaluate the incidence, risk factors, and effect on outcomes of right ventricular failure in a large population of patients implanted with continuous-flow left ventricular assist devices.Methods: Patients (n = 484) enrolled in the HeartMate II left ventricular assist device (Thoratec, Pleasanton, Calif) bridge-to-transplantation clinical trial were examined for the occurrence of right ventricular failure. Right ventricular failure was defined as requiring a right ventricular assist device, 14 or more days of inotropic support after implantation, and/or inotropic support starting more than 14 days after implantation. Demographics, along with clinical, laboratory, and hemodynamic data, were compared between patients with and without right ventricular failure, and risk factors were identified.Results: Overall, 30 (6%) patients receiving left ventricular assist devices required a right ventricular assist device, 35 (7%) required extended inotropes, and 33 (7%) required late inotropes. A significantly greater percentage of patients without right ventricular failure survived to transplantation, recovery, or ongoing device support at 180 days compared with patients with right ventricular failure (89% vs 71%, P < .001). Multivariate analysis revealed that a central venous pressure/pulmonary capillary wedge pressure ratio of greater than 0.63 (odds ratio, 2.3; 95% confidence interval, 1.2–4.3; P = .009), need for preoperative ventilator support (odds ratio, 5.5; 95% confidence interval, 2.3–13.2; P < .001), and blood urea nitrogen level of greater than 39 mg/dL (odds ratio, 2.1; 95% confidence interval, 1.1–4.1; P = .02) were independent predictors of right ventricular failure after left ventricular assist device implantation.Conclusions: The incidence of right ventricular failure in patients with a HeartMate II ventricular assist device is comparable or less than that of patients with pulsatile-flow devices. Its occurrence is associated with worse outcomes than seen in patients without right ventricular failure. Patients at risk for right ventricular failure might benefit from preoperative optimization of right heart function or planned biventricular support.

Risk factor analysis for postoperative acute respiratory distress syndrome and early mortality after pneumonectomy: The predictive value of preoperative lung perfusion distribution - Corrected Proof

Joon Bum Kim, Sei Won Lee, Seung-Il Park, Yong Hee Kim, Dong Kwan Kim — 2010-02-04

Objectives: This study aims to establish the preoperative risk factors in the development of acute respiratory distress syndrome (ARDS) and early mortality after pneumonectomy for lung cancer and to examine the influence of reduced pulmonary perfusion on outcomes.Methods: Between 1994 and 2009, of 425 patients who underwent simple pneumonectomy for primary lung cancer, 164 who were preoperatively evaluated with lung perfusion scanning formed the population of this study.Results: Of 30 (18.3%) patients who had major pulmonary complications, 17 (10.4%) progressed to ARDS, 15 of whom subsequently died. On multivariable logistic regression analyses, lower predicted postoperative forced expiratory volume in 1 second (ppo-FEV1; relative risk of 0.93 [P = .020] for ARDS and 0.94 [P = .027] for mortality) and greater perfusion fraction of resected lung (relative risk of 1.10 [P = .003] for ARDS and 1.09 [P = .002] for mortality) were found to be independent factors associated with ARDS and early mortality. With a cut-off value of 35% for perfusion fraction of resected lung, patients with a perfusion fraction of greater than 35% had a greater incidence of ARDS (17.3% vs 3.3%, P = .005) and early mortality (19.8% vs 6.0%, P = .010) than those with a perfusion fraction of 35% or less.Conclusions: Patients with a low ppo-FEV1, a high perfusion fraction of resected lung, or both had a higher incidence of ARDS and early mortality after pneumonectomy. Therefore, although the ppo-FEV1 appears to be within an acceptable limit for pneumonectomy, much attention should be given to patients with a high perfusion fraction of resected lung.

Effect of pressure management during hypothermic selective cerebral perfusion on cerebral hemodynamics and metabolism in pigs - Corrected Proof

2010-02-01

Objective: The effect of perfusion pressure on cerebral hemodynamics and metabolism during selective cerebral perfusion in patients undergoing aortic surgery is still unknown. This study explored cerebral blood flow, metabolic rate, and intracranial pressure at different pressure rates.Methods: Twenty-five pigs (32–38 kg) were cooled during cardiopulmonary bypass to 25°C. After 10 minutes of hypothermic circulatory arrest, the animals were randomized to 60 minutes of selective cerebral perfusion at 3 different perfusion pressures: group I (n = 8), 40 mm Hg; group II (n = 9), 60 mm Hg; and group III (n = 8), 80 mm Hg. Microspheres were injected at baseline, the coolest temperature, and 5, 15, 25, and 60 minutes of selective cerebral perfusion, respectively, to calculate cerebral hemodynamics.Results: Cerebral blood flow decreased during cooling to 54% of baseline value (50 mL/min per 100 g) and recovered in all groups during the first 15 minutes of selective cerebral perfusion. In groups I and II it reached 110% to 113% of baseline values, whereas group III animals showed significantly higher values (P25min = .003) during the first 25 minutes of selective cerebral perfusion (360%; 153 mL/min per 100 g). Cerebral blood flow decreased in all groups over the following 35 minutes of selective cerebral perfusion to 57% of baseline value. Cooling to 25°C decreased the intracranial pressure to 10 mm Hg (93%). During selective cerebral perfusion, groups I and II showed a further intracranial pressure decrease to 45% and 82%, respectively, whereas group III, with 15 mm Hg (128%), had significantly higher intracranial pressure values at the end of selective cerebral perfusion (P25min = .03 and P60min = .02). The metabolic rate decreased to 30% of the baseline value during cooling, reaching 34% to 38% after 60 minutes of selective cerebral perfusion, with no significant differences between groups.Conclusion: High-pressure perfusion provides no benefit during long-term selective cerebral perfusion at 25°C. Higher cerebral blood flow during the initial 25 minutes of selective cerebral perfusion leads to cerebral edema, with no alteration in metabolic rate.

Efficacy of a novel bipolar radiofrequency ablation device on the beating heart for atrial fibrillation ablation: A long-term porcine study - Corrected Proof

2010-02-01

Objective: Over recent years, a variety of energy sources have been used to replace the traditional incisions of the Cox maze procedure for the surgical treatment of atrial fibrillation. This study evaluated the safety and efficacy of a new bipolar radiofrequency ablation device for atrial ablation in a long-term porcine model.Methods: Six pigs underwent a Cox maze IV procedure on a beating heart off cardiopulmonary bypass using the AtriCure Isolator II bipolar ablation device (AtriCure, Inc, Cincinnati, Ohio). In addition, 6 pigs underwent median sternotomy and pericardiotomy alone to serve as a control group. All animals were allowed to survive for 30 days. Each pig underwent induction of atrial fibrillation and was then humanely killed to remove the heart en bloc for histologic assessment. Magnetic resonance imaging scans were also obtained preoperatively and postoperatively to assess atrial and ventricular function, pulmonary vein anatomy, valve function, and coronary artery patency.Results: All animals survived the operation. Electrical isolation of the left atrial appendage and the pulmonary veins was documented by pacing acutely and at 30 days in all animals. No animal that underwent the Cox maze IV procedure was able to be induced into atrial fibrillation at 30 days postoperatively, compared with all the sham animals. All 257 ablations examined were discrete, linear, and transmural, with a mean lesion width of 2.2 ± 1.1 mm and a mean lesion depth of 5.3 ± 3.0 mm.Conclusions: The AtriCure Isolator II device was able to create reliable long-term transmural lesions of the modified Cox maze procedure on a beating heart without cardiopulmonary bypass 100% of the time. There were no discernible effects on ventricular or valvular function.

Intermittent regurgitation caused by incomplete leaflet closure of the Medtronic ADVANTAGE bileaflet heart valve: Analysis of the underlying mechanism - Corrected Proof

2010-02-01

Objective: Clinical echocardiographic assessments of the Medtronic ADVANTAGE (Medtronic Inc, Minneapolis, Minn) prosthesis in the aortic position revealed a phenomenon identified as “intermittent regurgitation.” An in vitro investigation was initiated to identify the underlying mechanism.Methods: In a pulse duplicator environment, 6 ADVANTAGE size 23 aortic valves were analyzed. Leaflet motion and flow through the valves were documented using echocardiography with color Doppler flow, digital high speed imaging, and flow meter assessment.Results: Intermittent regurgitation could be reproduced in all 6 of the tested valves within limited ranges of flow, pressure, and valve orientation. By virtue of high-speed imaging, the mechanism underlying intermittent regurgitation was identified. During intermittent regurgitation, the leading edge of the second-to-close leaflet makes contact with the chamfer on the leading edge of the first-to-close leaflet. The fluid closing forces working on the first-to-close leaflet prevent it from shifting back so that the leading edge of the second-to-close leaflet remains positioned against the chamfer of the first-to-close leaflet. In this position, the major radius of the second-to-close leaflet does not reach the housing's major radius. Therefore, a crescent-shaped gap remains between the leaflet tip of the second-to-close leaflet and the housing major radius during all or part of diastole. The regurgitant fraction can increase from a normal range of 6% to 25% during an intermittent regurgitation beat.Conclusion: In vitro intermittent regurgitation can be induced in the size 23 aortic ADVANTAGE valve under a limited range of conditions. To avoid possible misinterpretations, the phenomenon must be known in detail by all physicians dealing with patients with an ADVANTAGE valve.

Functional mitral stenosis after surgical annuloplasty for ischemic mitral regurgitation: Importance of subvalvular tethering in the mechanism and dynamic deterioration during exertion - Corrected Proof

2010-02-01

Objective: Diastolic subvalvular mitral leaflet tethering by left ventricular remodeling that restricts leaflet opening in the presence of annular size reduction by surgery for ischemic mitral regurgitation potentially causes functional mitral stenosis in the absence of organic leaflet lesions. Exercise, known to worsen systolic tethering and ischemic mitral regurgitation, might also dynamically exacerbate such mitral stenosis by increasing tethering. This study evaluates the mechanism and response of such mitral stenosis to exercise.Methods: We measured the diastolic mitral valve area, annular area, and peak and mean transmitral pressure gradient by echocardiography in 20 healthy individuals and 31 patients who underwent surgical annuloplasty for ischemic mitral regurgitation.Results: Although the mitral valve area and annular area did not significantly differ in healthy individuals (4.7 ± 0.6 cm2 vs 5.2 ± 0.6 cm2, not significant), mitral valve area was significantly smaller than the annular area in patients after annuloplasty (1.6 ± 0.2 cm2 vs 3.3 ± 0.5 cm2, P < .01). The mitral valve area was less than 1.5 cm2 only after the surgery (P < .01) and was significantly correlated with restricted leaflet opening (r2 = 0.74, P < .001), left ventricular dilatation (r2 = 0.17, P < .05), and New York Heart Association functional class (P < .05). Exercise stress echocardiography of 12 patients demonstrated dynamic worsening in functional mitral stenosis (mitral valve area: 2.0 ± 0.5 cm2 to 1.4 ± 0.2 cm2, P < .01; mean pressure gradient: 1.5 ± 0.9 mm Hg to 6.0 ± 2.2 mm Hg, P < .01).Conclusion: Persistent subvalvular leaflet tethering in the presence of annular size reduction by surgery in ischemic mitral regurgitation frequently causes functional mitral stenosis at the leaflet tip level, which is related to heart failure symptoms and can be dynamic with significant exercise-induced worsening.

Thoracoscopic pulmonary vein isolation in patients with atrial fibrillation and failed percutaneous ablation - Corrected Proof

2010-02-01

Objective: Pulmonary vein isolation is indicated in patients with symptomatic isolated atrial fibrillation not controlled with antiarrhythmic therapy. We describe our surgical experience with thoracoscopic pulmonary vein isolation in patients in whom percutaneous ablation has failed.Methods: Thirty-four adult patients with unsuccessful catheter ablations (range 1–4, mean 2 ± 1) underwent thoracoscopic bipolar-radiofrequency pulmonary vein isolation. Seventeen patients had paroxysmal atrial fibrillation, 12 with persistent and 5 with long-standing persistent fibrillation, for a mean of 6 years (range 3–10 years), 13 years (5–25 years), and 9 years (3–15 years), respectively.Results: There was no mortality during the procedure or follow-up (mean 16 ± 11 months). Two patients needed conversion to thoracotomy owing to hemorrhage, and ablation could not be completed. Antiarrhythmic therapy was withdrawn 3 months postoperatively. Postoperative sinus rhythm was maintained in 82% of those with paroxysmal atrial fibrillation (13/15 at 6 months, 9/11 at 12 months), 60% had persistent atrial fibrillation (8/12 at 6 months and 6/10 at 12 months), and 20% had long-standing persistent atrial fibrillation (1/5 at 6 and 12 months). Preoperative left atrial diameter significantly differed between patients with paroxysmal fibrillation (mean 42 ± 6 mm) and those with persistent and long-standing persistent fibrillation (means 50 ± 4 and 47 ± 2 mm). Left atrial size greater than 45 mm and atrial fibrillation type were preoperative factors that significantly influenced outcome in the univariate logistic regression analysis.Conclusions: Thoracoscopic pulmonary vein isolation in patients with previously unsuccessful catheter ablations demonstrates satisfactory sinus rhythm maintenance rates in paroxysmal and persistent atrial fibrillation, but not in long-standing persistent atrial fibrillation. As with other minimally invasive surgical techniques, there is an important learning curve.

Explantation of a 44-year-old Starr–Edwards mitral valve for delayed hemolysis - Corrected Proof

Joss Fernandez, Robert Saeid Farivar — 2010-02-01

A 68-year-old woman was admitted 44 years after undergoing mitral valve replacement with a Starr–Edwards (SE) prosthesis (Edwards Lifesciences, Irvine, Calif) for rheumatic mitral valve stenosis. Since implantation of the prosthesis in 1965 via thoracotomy, the patient had done well and maintained her anticoagulation with warfarin sodium (Coumadin). She now had fatigue and anemia. Of note, 2 years earlier the patient had had third-degree heart block necessitating the implantation of a dual-chamber pacemaker. A full workup including upper and lower endoscopy did not reveal a source of bleeding. Hematologic testing showed decreased haptoglobin, a high lactic dehydrogenase value, and increased reticulocyte count, consistent with a hemolytic anemia. Bone marrow biopsy was performed, which showed erythroid hyperplasia, normocellular bone marrow, normal megakaryocytes, and absent iron, indicative of iron deficiency anemia. Despite iron replacement therapy she continued to become increasingly transfusion dependent. She received 9 units of blood in 1 month alone. Echocardiogram revealed normal prosthetic mitral valve function with a mitral valve mean gradient of 6 mm Hg, a severely calcified aortic valve with an aortic valve mean gradient of 58 mm Hg, and an aortic valve area of less than 1.0 cm2.

Secure closure of the tracheal incision after natural orifice transluminal endoscopic surgery with a silicone tracheal stent - Corrected Proof

Yun-Hen Liu, Yi-Chen Wu, Tzu-Ping Chen, Po-Jen Ko — 2010-02-01

Since its introduction in 2004, natural orifice transluminal endoscopic surgery (NOTES) has attracted the interest of many clinicians and researchers and demonstrated technical feasibility and efficacy when used in various types of intra-abdominal operations, including transgastric liver biopsy, cholecystectomy, tubal ligation, and peritoneoscopy.

Hybrid procedure as an alternative to surgical palliation of high-risk infants with hypoplastic left heart syndrome and its variants - Corrected Proof

2010-02-01

Objectives: Despite improvements in the surgical management of neonates with the hypoplastic left heart syndrome and its variants, there is a subset of children who have a high predicted mortality. We have analyzed and report our results with the hybrid approach in the management of these high-risk patients.Methods: Children identified by our selection criteria underwent the initial hybrid procedure performed in the catheterization laboratory. This consists of surgical banding of the branch pulmonary arteries and stenting of the arterial duct. This was followed 3 to 6 months later by the combined stage I and II Norwood operation or biventricular repair.Results: Between December 2005 and May 2008, 21 neonates were selected for the hybrid procedure, of whom 16 had typical hypoplastic left heart syndrome. The remaining 5 neonates had severe aortic stenosis with borderline left ventricular dimensions or poor left ventricular function at presentation. Four neonates had a virtually intact interatrial septum and required urgent intervention immediately after birth. There were 6 deaths as inpatients or up to 30 days after the procedure and 1 interstage death before the combined stage I and II operation. Thus far, of 12 babies who have undergone the next operation, 9 have had the combined stage I and II operation and 3 have had a biventricular repair. Two of these 12 babies have died after the combined stage I and II operation.Conclusion: A hybrid approach may be a valuable alternative to the management of high-risk neonates with hypoplastic left heart syndrome and its variants.

Noninvasive estimation of left ventricular filling pressures in patients with heart failure after surgical ventricular restoration and restrictive mitral annuloplasty - Corrected Proof

2010-02-01

Objective: Doppler echocardiography, including tissue Doppler imaging, is widely applied to assess diastolic left ventricular function using early transmitral flow velocity combined with mitral annular velocity as a noninvasive estimate of left ventricular filling pressures. However, the accuracy of early transmitral flow velocity/mitral annular velocity in patients with heart failure, particularly after extensive cardiac surgery, is debated. Global diastolic strain rate during isovolumic relaxation obtained with 2-dimensional speckle-tracking analysis was recently proposed as an alternative approach to estimate left ventricular filling pressures.Methods: We analyzed diastolic function in patients with heart failure after surgical ventricular restoration and/or restrictive mitral annuloplasty. Echocardiography, including tissue Doppler imaging and speckle-tracking analysis, was performed to determine early transmitral flow velocity/atrial transmitral flow velocity, isovolumetric relaxation time, deceleration time, early transmitral flow velocity/mean mitral annular velocity, strain rate during isovolumic relaxation, and early transmitral flow velocity/strain rate during isovolumic relaxation. These noninvasive indices were correlated with relaxation time constant Tau, peak rate of pressure decline, and left ventricular end-diastolic pressure obtained in the catheterization room using high-fidelity pressure catheters.Results: Twenty-three patients were analyzed 6 months after restrictive mitral annuloplasty (n = 8), surgical ventricular restoration (n = 4), or a combined procedure (n = 11). The strongest correlation with invasive indices, in particular left ventricular end-diastolic pressure, was found for strain rate during isovolumic relaxation (r = −0.76, P < .001). Early transmitral flow velocity/mean mitral annular velocity did not correlate significantly with any of the invasive indices. Strain rate during isovolumic relaxation (cutoff value < 0.38 s−1) accurately predicted left ventricular end-diastolic pressure of 16 mm Hg or more with 100% sensitivity and 93% specificity.Conclusion: In a group of patients with heart failure who were investigated 6 months after cardiac surgery, early transmitral flow velocity/mean mitral annular velocity correlated poorly with invasively obtained diastolic indexes. Global strain rate during isovolumic relaxation, however, correlated well with left ventricular end-diastolic pressure and peak rate of pressure decline. Our data suggest that global strain rate during isovolumic relaxation is a promising noninvasive index to assess left ventricular filling pressures in patients with heart failure after extensive cardiac surgery, including restrictive mitral annuloplasty and surgical ventricular restoration.

Technical considerations to avoid pitfalls during transapical aortic valve implantation - Corrected Proof

2010-02-01

Objective: Transapical aortic valve implantation is a recent therapeutic advance for aortic valvular disease. We sought to identify complications—and the relevant technical and management considerations—from our learning curve with this procedure.Methods: We retrospectively reviewed perioperative complications during the first 60 transapical aortic valve implantations at a single institution, performed under compassionate release for patients who were candidates neither for conventional aortic valve replacement nor for transfemoral aortic valve implantation. Access was through a small left anterolateral thoracotomy. Particular attention was paid to securing the apical access site. Rapid ventricular pacing to reduce cardiac forward flow was used during balloon valvuloplasty and valve deployment. Careful positioning was guided by echocardiography and fluoroscopy.Results: This was a select, high-risk (mean Society of Thoracic Surgeons score, 12.3% ± 7.8% mortality) cohort. Mean age was 81.1 ± 7.8 years. Technical success was achieved in 59 (98.3%) cases. One valve was malpositioned too far toward the ventricle, necessitating that a second device be implanted within it. In-hospital, 30-day mortality was 18.3% (11 deaths) overall, decreasing from 33.3% in the first 15 patients to 13.3% in the subsequent 45 patients. The only intraoperative death probably resulted from left main ostial obstruction by extensively calcified aortic cusps. Significant left ventricular apical bleeding occurred in 3 (5.0%) patients. Other complications included stroke in 2 (3.3%) patients and permanent atrioventricular block in 3 (5.0%). There were 4 (6.6%) cases of late pseudoaneurysm of the left ventricular apical access site.Conclusions: Important lessons have been learned from our early experience with transapical aortic valve implantation, and these may guide others as this technology is adopted more broadly.

A formidable task: Population analysis predicts a deficit of 2000 cardiothoracic surgeons by 2030 - Corrected Proof

Thomas E. Williams, Benjamin Sun, Patrick Ross, Andrew M. Thomas — 2010-02-01

Objective: To estimate the cardiovascular workforce needed by 2030 to meet the needs of our population and to quantify its costs. Our field is changing. The volume of surgery and the nature of the surgery are changing. The nation's population grew from 227,000,000 to 282,000,000 between 1980 and 2000, and by 2030 the population is estimated to be 364,000,000. At the same time, the applications for fellowship in our specialty are decreasing at an alarming rate. The American Board of Thoracic Surgery has certified 4500 cardiothoracic surgeons since 1975, but only 1300 in the last 10 years. The US Department of Health and Human Services predicts only 3620 full-time cardiothoracic surgeons in 2020. Will we have enough cardiovascular and thoracic surgeons?Methods: Retrospective examination of the pertinent literature and with a modified Richard Cooper's economic trend analysis, a population algorithm with a ratio of physicians to population of 1.42 per 100,000. Each thoracic surgeon is predicted to practice 30 years from Board certification to retirement. The Balanced Budget Act will not be revised; therefore, we will certify 100 graduates from our programs per year. The assumed salaries will be $50,000 with benefits of 30% and $15,000 of additional Direct Medical Education costs.Results: The population in 2030 will be 364,000,000 with 5169 cardiothoracic surgeons needed at that time. Unfortunately, there will be approximately only 3200 cardiothoracic surgeons in practice with a shortage of approximately 2000. To maintain our current status per 100,000 population from 2011 to 2030, we will have to train 4000 residents. The total person years would be approximately 28,000. The cost for this is more than $2,000,000,000. The annual cost for this training prorated over 20 years would be more than $110,000,000.Conclusion: We must train approximately 4000 surgeons, an extra 100 per year, in our specialty to meet the needs of the population by 2030. That will cost approximately $2,250,000,000. To do this, the Balanced Budget Act of 1997 must be revised to permit more residents to be trained in the United States.

Effects of partial thrombosis on distal aorta after repair of acute DeBakey type I aortic dissection - Corrected Proof

2010-02-01

Objective: Prognostic implications of partial thrombosis of the residual aorta after repair of acute DeBakey type I aortic dissection have not been elucidated. We sought to analyze the impact of partial thrombosis on segmental growth rates, distal aortic reprocedures, and long-term survival.Methods: A total of 118 consecutive patients (55% were male; mean age, 60 years) with acute DeBakey type I aortic dissection underwent surgical repair (1997–2007). The hospital mortality rate was 17.8%. Survivors underwent serial computed tomography scans. Segment-specific average rates of enlargement were analyzed. Distal reprocedures and patient survival were examined.Results: Sixty-six patients had imaging data sufficient for growth rate calculations. The median diameters within 2 weeks after repair were as follows: aortic arch, 3.5 cm; descending aorta, 3.6 cm; and abdominal aorta, 2.4 cm. Subsequent growth rates were artic arch, 0.34 mm/y, descending aorta, 0.51 mm/y, and abdominal aorta, 0.35 mm/y. Partial thrombosis of the residual aorta predicted greater growth in the distal aorta (P = .005). There were 13 distal aortic reprocedures (5 reoperations, 8 stent graft insertions) for 10 years, and reprocedure-free survival was 66%. Partial thrombosis (P = .002) predicted greater risk of aorta-related reprocedures. Cox analysis revealed that estimated glomerular filtration rate less than 60 mL/min/1.73 m2 (P = .030), reintubation (P = .002), and partial thrombosis (P = .023) were independent predictors for poor survival.Conclusion: Partial thrombosis of the false lumen after repair of acute DeBakey type I aortic dissection, compared with complete patency or complete thrombosis, is a significant independent predictor of aortic enlargement, aorta-related reprocedures, and poor long-term survival.

Discussion - Corrected Proof

2010-02-01

Dr Anthony Estrera (Houston, Tex). I have nothing to disclose. As referenced by Dr Song, a recent evaluation of the IRAD experience demonstrated the potentially detrimental effect of the partially thrombosed false lumen in aortic dissection. This study by Song and colleagues analyzed this effect in relation to post-repair of acute type I aortic dissection. The strength of this study is not in the early results but rather the late follow-up. Song and colleagues determined, in addition to decreased late survival, greater aortic growth, and more frequent aortic reinterventions were observed in those patients with a partially thrombosed false lumen, giving us some potential causes for this increased late mortality.

Discussion - Corrected Proof

2010-02-01

Dr Irving Kron (Charlottesville, Va). The authors make the case that there will be a predicted shortage of surgeons in the United States by the year 2030. The American Association for Thoracic Surgeons and the Society of Thoracic Surgeons in association with the Association of American Medical Colleges developed an article that is now in press in Circulation that pretty much comes up with the same conclusion, about a 25% shortage of CT surgeons by 2025.

How much of the intraaortic balloon volume is displaced toward the coronary circulation? - Corrected Proof

Christina Kolyva, George M. Pantalos, John R. Pepper, Ashraf W. Khir — 2010-01-18

Objective: During intraaortic balloon inflation, blood volume is displaced toward the heart (Vtip), traveling retrograde in the descending aorta, passing by the arch vessels, reaching the aortic root (Vroot), and eventually perfusing the coronary circulation (Vcor). Vcor leads to coronary flow augmentation, one of the main benefits of the intraaortic balloon pump. The aim of this study was to assess Vroot and Vcor in vivo and in vitro, respectively.Methods: During intraaortic balloon inflation, Vroot was obtained by integrating over time the aortic root flow signals measured in 10 patients with intraaortic balloon assistance frequencies of 1:1 and 1:2. In a mock circulation system, flow measurements were recorded simultaneously upstream of the intraaortic balloon tip and at each of the arch and coronary branches of a silicone aorta during 1:1 and 1:2 intraaortic balloon support. Integration over time of the flow signals during inflation yielded Vcor and the distribution of Vtip.Results: In patients, Vroot was 6.4% ± 4.8% of the intraaortic balloon volume during 1:1 assistance and 10.0% ± 5.0% during 1:2 assistance. In vitro and with an artificial heart simulating the native heart, Vcor was smaller, 3.7% and 3.8%, respectively. The distribution of Vtip in vitro varied, with less volume displaced toward the arch and coronary branches and more volume stored in the compliant aortic wall when the artificial heart was not operating.Conclusion: The blood volume displaced toward the coronary circulation as the result of intraaortic balloon inflation is a small percentage of the nominal intraaortic balloon volume. Although small, this percentage is still a significant fraction of baseline coronary flow.