The Journal of Thoracic and Cardiovascular Surgery
Volume 133, Issue 3 , Pages 623-631, March 2007

Does off-pump or minimally invasive coronary artery bypass reduce mortality, morbidity, and resource utilization when compared with percutaneous coronary intervention? A meta-analysis of randomized trials

Presented at the Health Technology Assessment International (HTAi) Conference in Rome, June 20–22, 2005.

  • Daniel Bainbridge, MD, FRCPC

      Affiliations

    • Department of Anesthesia & Perioperative Medicine, London Health Sciences Centre, University of Western Ontario, London, Ontario, Canada
    • Assistant Professor.
    • ,
  • Davy Cheng, MD, MSc, FRCPC

      Affiliations

    • Department of Anesthesia & Perioperative Medicine, London Health Sciences Centre, University of Western Ontario, London, Ontario, Canada
    • Professor and Chair, Department of Anesthesia.
    • Corresponding Author InformationAddress for reprints: D. Cheng, MD, MSc, FRCPC, Department of Anesthesia & Perioperative Medicine, London Health Sciences Centre—University Hospital, 339 Windermere Rd, Room 3-CA19, London, Ontario, Canada N6A 5A5.
    • ,
  • Janet Martin, PharmD

      Affiliations

    • Department of Pharmacy, Physiology & Pharmacology, London Health Sciences Centre, University of Western Ontario, London, Ontario, Canada
    • Director, High Impact Technology Evaluation Centre (HiTEC).
    • ,
  • Richard Novick, MD, MSc, FRCSC

      Affiliations

    • Division of Cardiac Surgery, London Health Sciences Centre, University of Western Ontario, London, Ontario, Canada.
    • Professor and Head, Division of Cardiac Surgery.
    • ,
  • The Evidence-based Peri-operative Clinical Outcomes Research (EPiCOR) Group

Received 11 September 2006; received in revised form 25 October 2006; accepted 1 November 2006.

Article Outline

Objective

To determine, through meta-analysis, whether off-pump coronary artery bypass, including minimally invasive off-pump coronary artery bypass, improves short-term and midterm outcomes compared with percutaneous coronary intervention for single- or double-vessel coronary artery disease.

Methods

The primary outcome was need for coronary reintervention at 1 to 5 years. Secondary outcomes included all major clinical morbidities and resource utilization. A comprehensive search was undertaken to identify all randomized trials of off-pump coronary artery bypass versus percutaneous coronary intervention. MEDLINE, Cochrane Library, EMBASE, and abstract databases were searched up to May 2006. All randomized trials comparing off-pump coronary artery bypass (sternotomy or minimally invasive) versus percutaneous coronary intervention and reporting at least one predefined outcome were included. Odds ratios (OR, 95% confidence intervals [CI]) and weighted mean differences (WMD, 95% CI) were analyzed.

Results

Six trials involving 989 patients were included. Compared with percutaneous coronary intervention, off-pump coronary artery bypass decreased angina recurrence (OR 0.54, 95% CI 0.34–0.87) and need for reintervention at 1 to 5 years (OR 0.24, 95% CI 0.15–0.40). Major adverse coronary events were significantly reduced (OR 0.44, 95% CI 0.30–0.63) and event-free survival was significantly increased at 1 to 5 years (OR 2.32, 95% CI 1.62–3.32) for off-pump coronary artery bypass versus percutaneous coronary intervention. Coronary stenosis at 6 months was reduced with off-pump coronary artery bypass compared with percutaneous coronary intervention (OR 0.31, 95% CI 0.18–0.55). Hospital stay was significantly increased with off-pump coronary artery bypass versus percutaneous coronary intervention (WMD 4.03, 95% CI 2.37–5.70). Quality of life favored off-pump coronary artery bypass in some domains but was reported in few studies. Death, myocardial infarction, and stroke did not significantly differ.

Conclusions

In single- or double-vessel disease, off-pump coronary artery bypass improved short-term and midterm clinical outcomes compared with percutaneous coronary intervention but was associated with an increased length of hospital stay.

CTSNet classification: 23, 25, 28

Abbreviations and Acronyms: CABG, coronary artery bypass grafting, CCAB, conventional coronary artery bypass, CROQ, Coronary Revascularization and Outcome Questionnaire, EQ-5D, EuroQOL, LOS, length of stay, MACE, major adverse coronary events, MIDCAB, minimally invasive off-pump coronary artery bypass, OPCAB, off-pump coronary artery bypass, OR, odds ratio, PCI, percutaneous coronary intervention, SAQ, Seattle Angina Questionnaire, SF-36, short-form health survey, WMD, weighted mean differences

 

Although it has been demonstrated that conventional coronary artery bypass surgery (CCAB) may prolong life and reduce symptoms, these benefits are tempered by risks including mortality (2%–5%), stroke (2%), transfusions (30%–90%), atrial fibrillation (30%), and neurocognitive dysfunction (50%−75%).1, 2, 3, 4 Consequently, there has been an upsurge of interest in safer alternatives to CCAB, including percutaneous coronary intervention with stenting (PCI) and off-pump beating heart bypass surgery (OPCAB), with avoidance of cardiopulmonary bypass.5, 6 Several randomized trials have compared PCI with CCAB and demonstrated increased rates of angina or need for reintervention in the PCI cohort,1, 7, 8, 9, 10, 11 whereas overall costs were reduced in the short term.9 Outcomes with PCI were generally worse in patients with diabetes and in those with multivessel disease.12, 13 PCI is most commonly performed in limited target vessels; thus it may not be appropriate to compare its outcomes with multivessel CCAB.14

Comparisons of OPCAB and CCAB surgery have demonstrated improvement in short-term outcomes favoring OPCAB for atrial fibrillation, blood transfusion, and length of hospital stay in patients unselected for risk (ie, in mixed-risk patient populations).15 There is further evidence indicating OPCAB improves mortality, morbidity, and resource utilization when compared with CCAB in high-risk patients.16 However, patients undergoing OPCAB had slightly fewer anastomoses, suggesting some limitations for multiple target revascularizations using OPCAB surgical technique.15 Therefore, comparing PCI with OPCAB would seem the more relevant comparison in patients with one- or two-vessel coronary artery disease.

We sought to determine, through systematic review with meta-analysis of all relevant randomized trials, whether OPCAB reduces mortality, morbidity, or resource utilization when compared with PCI.

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Materials and Methods 

Searching for Trials 

This meta-analysis was performed in accordance with QUOROM⁎ recommendations and according to a protocol that pre-specified outcomes, search strategies, inclusion criteria, and statistical analyses.17 A search was undertaken in accordance with Cochrane Collaboration recommendations to identify all published or unpublished randomized trials of OPCAB versus CCAB or PCI, in any language. MEDLINE, Cochrane CENTRAL, EMBASE, Current Contents, DARE, NEED, and INAHTA† databases were searched from the date of their inception to May 2006. Search terms included variants of off-pump, minimally invasive, beating heart, and coronary artery bypass. Tangential electronic exploration of related articles and hand searches of bibliographies, scientific meeting abstracts, and related journals were also performed.

Inclusion Criteria 

Studies were included if they met each of the following: (1) adult patients with single- or multiple-vessel coronary artery disease suitable for revascularization with either OPCAB or PCI; (2) randomized allocation to OPCAB on the beating heart (via thoracotomy or minimally invasive technique) versus PCI (with or without stenting); and (3) reporting at least one pertinent clinical or economic outcome. Blinded and unblinded studies were included, in any language. Hybrid (ie, OPCAB plus PCI) and robotically assisted surgery studies were excluded.

Data Extraction 

Two authors independently identified trials for inclusion and extracted information on demographics, interventions, and outcomes. Authors of included trials were contacted when necessary to clarify data and to identify multiple publications. Two reviewers independently assigned each trial a Jadad quality score18 that evaluates randomization, blinding, and completeness of follow-up (maximum score, 5). Disagreements were resolved by consensus.

End Points 

The primary outcome was defined as the need for reintervention for ischemia. Secondary outcomes included postoperative incidence of major adverse coronary events (MACE), all-cause mortality, stroke, acute myocardial infarction, atrial fibrillation, renal failure, need for inotropes, need for intra-aortic balloon pump, mediastinitis or wound infection, respiratory infections, angina recurrence, restenosis, need for transfusions, re-exploration for bleeding, neurocognitive dysfunction, intensive care unit (ICU) length of stay (LOS), hospital LOS, hospital costs, and quality of life (QOL). The original study authors’ definition of MACE was used and usually included the composite of death, acute myocardial infarction, and need for reintervention, and sometimes included stroke. Reintervention for ischemia was defined as requirement for either PCI or CABG occurring anytime throughout the trial. Stenosis and atrial fibrillation were defined according to study authors’ definitions. Acute myocardial infarction was defined per study authors’ definitions of new-onset infarction using electrocardiographic or enzymatic criteria. Mediastinitis and wound infection were defined as deep or superficial wound infections of the chest or catheter-related infections; they excluded leg wound infections. Respiratory infection was defined according to authors’ definitions, whether or not confirmed by chest x-ray film. Need for a transfusion was defined as the number of patients requiring red blood cell transfusion. Renal failure was defined as a new rise in serum creatinine of more than 50%, decline in creatinine clearance of more than 50%, or requirement of dialysis. Since no standard definition exists for neurocognitive dysfunction, we planned to include only studies reporting neurocognitive dysfunction dichotomously, and when tests in accordance with the statement of consensus were used.19 Duration of ventilation was measured from the end of surgery to the time of tracheal extubation. ICU LOS and hospital LOS were measured from the end of surgery until ICU or hospital discharge, respectively.

Statistical Analysis 

Outcomes were analyzed as dichotomous variables, with the exception of duration of ventilation, LOS, costs, and QOL, which were analyzed as continuous variables when the mean and standard deviation were reported. For dichotomous variables, odds ratios and 95% confidence intervals (OR, 95% CI) were calculated. For continuous variables, the weighted mean difference (WMD, 95% CI) was calculated for duration of ventilation and LOS. Standardized mean differences were planned to be calculated for costs and QOL; however, these outcomes were insufficiently reported for combined analyses. When significant differences were found for proportions, the absolute risk reduction and number needed to treat were calculated.20 Heterogeneity was explored using I2. The I2 indicates the proportion of variability between trials that cannot be attributable to chance alone; it provides an improved measure of hetereogeneity between trials that is not limited by power.21, 22 Values of I2 higher than 50% were considered to indicate significant heterogeneity between trials.

For each outcome, the Mantel–Haenszel (fixed effect) or DerSimonian and Laird (random effects) model was used when I2 suggested lack (≤50%) or presence (>50%) of heterogeneity, respectively. Pooled effect estimates and heterogeneity between studies were analyzed by use of Comprehensive MetaAnalysis (Englewood, NJ, 2002) and RevMan (v4.2, Cochrane Collaboration, 2003). Other than for the Q-test, statistical significance was defined as P < .05 or a confidence interval that excluded the possibility of no effect. All tests of statistical significance were 2-sided. Whenever possible, data analysis was by intention-to-treat.

Subgroup analysis was planned for single- versus multiple-vessel disease and for drug-eluting stents versus bare metal stents. Sensitivity analysis was planned to explore the potential effect of trial quality, publication status, and patients excluded in non–intention-to-treat trials using a worst-case scenario assumption. Publication bias was explored through visual inspection of funnel plots in which the inverse of the estimated variance of the natural logarithm of the adjusted relative risk was plotted against the natural logarithm of the adjusted relative risk for each outcome.23

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Results 

A total of 11 papers reporting on 6 trials involving 989 patients provided data for this meta-analysis (Figure 1 and Table 1).24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 The median Jadad score was 3 (range 2–3).18 Significant heterogeneity was found for reintervention at 6 months, angina recurrence at 6 months, and hospital LOS. Funnel plots showed no clear evidence of publication bias for any end point, although they were underpowered to do so. Patient demographics at baseline were similar (Table 2).

TABLE 1. Characteristics of included trials
AuthorNJadad scoreVesselsPatientsInterventionYearCountry
Cisowski25, 26 (02)1002,0,11Isolated A-, B-type lesions of proximal LADMIDCAB2000-2001Poland
Diegeler27, 28 (02)2202,0,11Isolated proximal LAD stenosis; elective, EF > 35%MIDCAB1997-2001Germany
Drenth29, 30, 31, 32 (02)1022,0,11Isolated LAD stenosis of type B2 or C; CCS class 2 or greater; first-time CABGMIDCAB1997-1999Netherlands
Eefting33 (03) (OctoStent)2802,0,1≥1Included single- or multiple-vessel disease, stable or unstable angina (Braunwald class I–IIB). Excluded left main stem stenosis, poor LVEF, emergency revascularization, recent MI, previous surgical revascularization, or PCI within 6 moOPCAB/MIDCAB1998-2000Netherlands
Reeves24 (04) (AMIST)1002,0,11Included isolated proximal LAD stenosis > 50%, elective or urgent. Excluded emergency (required within 24 h), LVEF < 30%, COPD, previous revascularization, total occlusion of LAD.MIDCAB1999-2001United Kingdom
Hong34 (05)1891,0,11Included isolated high-grade lesion (>70% of the luminal diameter) in proximal LAD. Excluded AMI, prior coronary revascularization, or total occlusion of LADMIDCAB2003Korea
Summary, OPCAB vs PCI (6 studies)989Median: 3≥1Mainly isolated LITA-LADOPCAB/MIDCAB1997-2003European/Asian

AMI, Acute myocardial infarction; AMIST, Angioplasty versus Minimally Invasive Surgery Trial; CABG, coronary artery bypass graft; CCS, Canadian Cardiovascular Society; COPD, chronic obstructive pulmonary disease; EF, ejection fraction; LAD, left anterior descending; LITA, left internal thoracic artery; LVEF, left ventricular ejection fraction; MI, myocardial infarction; MIDCAB, minimally invasive direct coronary artery bypass; OPCAB, off-pump coronary artery bypass; PCI, percutaneous coronary intervention.

TABLE 2. Patient characteristics
OPCABPCI
Age (mean y)58.9(9.8)58.2(10.1)
Female (%)3134
Diabetic (%)2123
History of MI (%)2932
Smoker (%)3033
Hyperlipidemia (%)6161
Crossovers (%)4.82.0

MI, Myocardial infarction; OPCAB, off-pump coronary artery bypass; PCI, percutaneous coronary intervention.

Although 5 of 6 trials comparing PCI versus OPCAB were exclusively of left anterior descending stenting versus left internal thoracic artery−to−left anterior descending anastomosis, one trial included patients with multivessel disease.33 The mean number of stents implanted per patient in this latter trial was 1.44.33 The majority of stents were implanted for stenosis in the left anterior descending coronary artery. Five trials used MIDCAB technique in the majority of patients in the surgical arm.24, 25, 27, 30, 34 In one trial, surgical access to the heart was achieved via median sternotomy in 67%, left anterior thoracotomy in 30%, and left posterolateral, xiphoid laparotomy, or partial sternotomy in the remainder.33 While one trial allowed either stenting or angioplasty,24 all patients except 6 in the PCI cohort received a stent. Five trials employed bare metal stents,24, 25, 27, 30, 33 whereas one trial34 used either sirolimus-eluting (Cypher; Cordis, Roden, The Netherlands) or paclitaxel-eluting (Taxus; Boston Scientific, Galway, Ireland) stents. Anticoagulation after stent placement consisted of ticlopidine/clopidogrel and aspirin in 5 trials,24, 25, 27, 30, 34 and was not stated in one trial.33 Ticlopidine/clopidogrel was maintained for 4 weeks in the case of bare metal stents and 6 months for drug-eluting stents. Crossovers from OPCAB to PCI occurred in 4.8% of patients, whereas crossovers from PCI to OPCAB occurred in 2.0% of patients after randomization.

Table 3 and Figure 2, Figure 3, Figure 4 outline the results. Compared with PCI, OPCAB reduced the risk of reintervention for ischemia at 1 to 5 years by 76% (OR 0.24, 95% CI 0.15–0.40). The odds of reintervention did not differ in hospital (OR 0.77, 95% CI 0.35–1.68) or at 6 months (OR 0.45, 95% CI 0.16–1.29). Angina recurrence was significantly reduced in favor of OPCAB in hospital (OR 0.42, 95% CI 0.25–0.71) and at 1 to 5 years (OR 0.54, 95% CI 0.34–0.87), but not at 6 months (OR 0.57, 95% CI 0.25–1.28). MACE was significantly reduced in favor of OPCAB at 6 months (OR 0.40, 95% CI 0.23–0.69) and at 1 to 5 years (0.44, 95% CI 0.30–0.63). Event-free survival was significantly improved at 6 months and at 1 to 5 years (Table 3). Six-month stenosis rates were significantly reduced (OR 0.31, 95% CI 0.18–0.55). However, hospital LOS was significantly increased with OPCAB versus PCI (WMD 4.0, 95% CI 2.4–5.7). When subgroup analysis was performed for trials using bare metal stents and excluding studies using drug-eluting stents, the results did not materially change with the exception of reintervention at 6 months, which was significantly reduced in favor of OPCAB (OR 0.26, 95% CI 0.14–0.49) (Table 4).

TABLE 3. Results
OutcomeOPCAB (%)PCI (%)OR (95% CI)I2 (%)P value for effect
Death, in hospital1.30.42.01(0.56–7.23)0.28
Death, 6 months2.51.51.61(0.51–5.05)0.42
Death, 1 to 5 years5.93.51.51(0.72–3.18)20.27
AMI, in hospital3.02.91.11(0.5–2.47)0.8
AMI, 6 months2.83.40.93(0.35–2.49)17.81
AMI, 1 to 5 years4.04.80.92(0.45–1.9)0.82
Stroke, in hospital0.50.31.56(0.29–8.34)0.61
Stroke, 6 months0.61.90.43(0.6–2.95)0.39
Stroke, 1 to 5 years01.10.35(0.03–3.97)0.4
Angina recurrence, in hospital6.813.80.42(0.25–0.71)0<.0001
Angina recurrence, 6 months13.118.70.57(0.25–1.28)66.17
Angina recurrence, 1 to 5 years12.823.30.54(0.34–0.87)38.01
Reintervention, in hospital2.33.20.77(0.35–1.68)0.51
Reintervention, 6 months6.815.20.45(0.16–1.29)60.14
Reintervention, 1 to 5 years5.819.70.24(0.15–0.40)0<.0001
MACE, in hospital2.83.80.86(0.27–2.74)22.80
MACE, 6 months8.921.60.40(0.23–0.69)25<.001
MACE, 1 to 5 years14.326.80.44(0.30–0.63)0<.0001
Event-free survival, 6 months87.673.72.53(1.50–4.27)0<.0001
Event-free survival, 1 to 5 years83.869.92.32(1.62–3.32)0<.0001
Stenosis, 6 months10.328.00.31(0.18–0.55)47<.0001
Wound complications, in hospital3.50.92.54(0.62–10.45)0.20

AMI, Acute myocardial infarction; CI, confidence intervals; MACE, major adverse coronary events; OPCAB, off-pump coronary artery bypass; OR, odds ratio; PCI, percutaneous coronary intervention.

TABLE 4. Subgroup analysis: Bare metal stent angioplasty (excluding drug-eluting stents)
OutcomeOPCAB (%)PCI (%)OR (95% CI)I2 (%)P value for effect
Angina recurrence, in hospital6.813.80.42(0.25–0.71)0<.0001
Angina recurrence, 1 to 5 years12.823.30.25(0.12–0.54)0<.0001
Reintervention, 1 to 5 years3.713.40.25(0.12–0.54)0<.0001

OPCAB, off-pump coronary artery bypass; PCI, percutaneous coronary intervention; OR, operating room; CI, confidence interval.

Compared with PCI, all-cause mortality, stroke, myocardial infarction, and wound complications were not reduced with OPCAB at any time point (Table 3). Other outcomes including atrial fibrillation, renal dysfunction, inotropic requirements, need for intra-aortic balloon pump, blood transfusion requirements, re-exploration for bleeding, ICU LOS, and neurocognitive function were insufficiently reported to perform meta-analysis.

QOL 

QOL was measured in 2 studies, and results were not combined through meta-analysis because different QOL scales were used. Eefting and associates33 measured EuroQOL (EQ-5D) and short-form health survey (SF-36) and found that at 1 month, EQ-5D and many domains of the SF-36 were significantly higher after PCI than after OPCAB, but this difference was no longer found at 1 year. In addition, Reeves and colleagues24 found that EQ-5D, SF-36, Seattle Angina Questionnaire (SAQ) and Coronary Revascularization and Outcome Questionnaire (CROQ) at 3 months, 6 months, and 12 months tended to favor OPCAB, although only three domains reached statistical significance (SF-36 mental composite score at 12 months, P = .04; SAQ treatment satisfaction score at 3 months, P = .02; CROQ cognitive score at 3 months, P = .04). SAQ dimensions of angina stability and frequency and CROQ physician and cognitive dimensions suggest the most consistent benefit of OPCAB, but without statistical significance. Since a large number of comparisons were tested for QOL domains, the finding of statistical significance should be interpreted with caution owing to the increased risk of spurious positive findings with multiple testing. Eefting and colleagues33 found an estimated gain in quality-adjusted life-years was 0.82 after PCI and 0.79 after OPCAB, and Reeves and coworkekrs24 estimated gain in quality-adjusted life-years of 0.77 after PCI and 0.82 after OPCAB.

Economic Outcomes 

Three trials reported economic outcomes.24, 25, 33 When direct costs during hospitalization or up to 1 year were considered, OPCAB was more costly than PCI, despite the added costs of increased reinterventions with PCI over 6- to 12-month follow-up (Table 5). Estimates of incremental cost-effectiveness were reported in 2 trials, with widely varying results (Table 6). Pooled analysis of economic outcomes was not practical owing to differences in methods of collecting and reporting costs.

TABLE 5. Direct costs during hospitalization (or up to 1 year)
StudyOPCAB mean direct cost (SD) per patientPCI mean direct cost (SD) per patientSummary
Cisowski25 (02)2000 USD at 30 d1600 USD at 30 dMIDCAB > PCI; P not reported
Eefting33 (03) (OctoStent)7508 EUR in hospital (9518 EUR at 1 y)5013 EUR in hospital (7043 EUR at 1 y)
OPCAB > PCI; P < .01

OPCAB > PCI; P < .01

Reeves24 (02)
2114 GBP in hospital

2681 GBP at 1 y


1093 GBP in hospital

1789 GBP at 1 y


OPCAB > PCI; P not reported

OPCAB > PCI; P not reported

EUR, Euro; GBP, Great Britain pound; OPCAB, off-pump coronary artery bypass; PCI, percutaneous coronary intervention; SD, standard deviation; USD, US dollars.

TABLE 6. Cost-effectiveness
StudyOPCAB total⁎ cost per QALYPCI total⁎ cost per QALYIncremental cost per QALY
Eefting33 (03) (OctoStent)1,1209/0.79$8276/0.82−2933/0.03=−97,767EUR/QALY
Reeves24 (04)2681/0.821789/0.77892/0.02=+44,600GBP/QALY

EUR, Euro; GBP, Great Britain pound; OPCAB, off-pump coronary artery bypass; PCI, percutaneous coronary intervention; QALY, quality-adjusted life year.

⁎Direct + indirect costs at 1 year.

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Discussion 

Compared with PCI, OPCAB decreased the odds of reintervention by 76%, recurrent angina by 46%, and occurrence of MACE by 56% at 1 to 5 years, requiring an average hospital LOS that is 4 days or greater.

These results have significant implications when projected over a large population. For example, given the aggregate estimates in this meta-analysis, for every 1000 low-risk patients undergoing off-pump surgery (ie, primarily left internal thoracic artery–left anterior descending artery revascularization), there will be an estimated 105 fewer patients with angina, 143 fewer patients requiring reintervention, and 125 fewer patients with MACE at 1 to 5 years. Whether OPCAB increases or decreases overall costs over the midterm to long-term relative to PCI remains uncertain, because few studies reported resource utilization.

Studies comparing CCAB and PCI (angioplasty) have demonstrated an improvement in short-term outcomes with PCI, such as length of hospital stay and cost. Unfortunately, patients randomized to PCI typically experience higher rates of recurrent angina requiring repeat revascularization procedures. The largest trial to date of angioplasty versus CCAB, the BARI trial (Bypass Angioplasty Revascularization Investigation), demonstrated that patients who had diabetes or multiple-vessel disease derived the greatest benefit from CCAB.12, 13 Although trials comparing percutaneous coronary stenting and CCAB have demonstrated a reduction in recurrent angina and restenosis compared with angioplasty, they still do not demonstrate equivalent efficacy to CCAB in these outcomes.7, 9, 35 The recent introduction of drug-eluting stents may further reduce the occurrence of recurrent angina and restensois36, 37; however, it is still unclear whether they will prove equivalent to CCAB procedures. Comparisons of drug-eluting stents to CCAB may be incomplete until optimal drug dosage and delivery have been ascertained, and one drug-eluting stent may not be equally efficacious to others.36, 37

Unfortunately, economic outcomes were insufficiently reported in the present review to allow for conclusions regarding incremental cost-effectiveness for OPCAB and PCI. Although initial costs favor PCI over CCAB, follow-up costs related to repeat revascularization reduce any economic advantage of PCI.38 The use of drug-eluting stents, which reduces the need for revascularization, may potentially reduce these reintervention costs related to PCI. However, numerous studies have suggested that drug-eluting stents, at current prices, are not likely to be considered cost-effective.39, 40, 41 Indeed, a cost-effectiveness analysis from the province of Ontario, Canada, found that the incremental cost of drug-eluting stents compared with bare metal stents for 1 quality-adjusted life-year was $223,580 Canadian dollars in non–post myocardial infarction diabetic patients having discrete lesions and $477,736 Canadian dollars in these same patients with long or narrow lesions.42

Whereas the short-term and medium-term benefits of OPCAB surgery seem clear in the hands of experienced surgeons,15, 16 the long-term results are too infrequently reported in the current literature to draw definitive conclusions. Of particular concern is graft patency, which has been demonstrated to be inferior in one randomized trial of OPCAB versus CCAB43 and not inferior in several other randomized trials.44, 45, 46 Although OPCAB initially was introduced with widespread enthusiasm, its frequency seems to have reached a plateau and it is being reserved increasingly for higher-risk patients with significant aortic disease.16

Given an increasing number of options for treatment of coronary artery disease, the need to identify subgroups of patients who benefit from a specific treatment option becomes imperative. The challenge is in balancing short- and long-term risk with benefits.

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Strengths, Limitations, and Generalizability 

Most trials for OPCAB versus PCI included only patients with single-vessel disease of the left anterior descending coronary artery, precluding inferences to patients with multivessel disease. Whether drug-eluting stents, which have been shown to significantly reduce restenosis and repeat revascularization rates by up to 83%, would mitigate the observed differences in restenosis and reintervention between OPCAB and PCI remains to be addressed.47 However, randomized studies of drug-eluting stents have failed to demonstrate improvements in rates of mortality or myocardial infarction.36

The rigor of this meta-analysis, as evidenced by comprehensive searches for randomized trials of all relevant outcomes and comparisons in any language, and the adherence to QUOROM recommendations, serves to increase confidence that this represents a complete summary of best available evidence. When heterogeneity was accounted for statistically, the conclusions remained unchanged for each heterogeneous outcome. Although the median Jadad quality score was 3 out of 5, this is common for meta-analysis of randomized trials (especially those in the field of surgery) and does not necessarily mean the trials were of low quality, but rather that key methodologic details were not reported.48

Although our analysis delineates the landscape of existing evidence, it also serves to highlight gaps that remain. Most notable is the lack of research defining long-term clinical, economic, and QOL outcomes associated with differing revascularization techniques. Accordingly, theoretical concerns about the quality and patency of grafts performed on the beating heart have not been adequately addressed by long-term follow-up of randomized trials to date, although survival and reintervention rates at up to 5 years have been encouraging (Table 3). Also notable is the lack of randomized controlled studies in higher-risk patients.

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Conclusions 

In conclusion, OPCAB reduces the need for reintervention, angina recurrence, and incidence of MACE at 1 to 5 years when compared with PCI. The overall impact on QOL and health system resource utilization remains unknown and warrants further study.

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References 

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  • ⁎ QUOROM = Quality of Reporting of Meta-analyses,
  • † DARE = Database of Abstracts of Reviews of Effects; NEED = NHS Economic Evaluation Database; INAHTA = International Network of Agencies for Health Technology Assessment.

 Funding: Department of Anesthesia and Perioperative Medicine, University of Western Ontario and from an HTA Capacity Building Grant awarded by the Canadian Coordinating Office of Health Technology Assessment (CCOHTA). No funds were received from proprietary sources.Ethics approval was not required for the conduct of this study.

PII: S0022-5223(06)02119-2

doi:10.1016/j.jtcvs.2006.11.019

The Journal of Thoracic and Cardiovascular Surgery
Volume 133, Issue 3 , Pages 623-631, March 2007

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