The Journal of Thoracic and Cardiovascular Surgery
Volume 139, Issue 6 , Pages 1673-1674, June 2010

Reply to the Editor

  • Lakshmi P. Dasi, PhD

      Affiliations

    • Department of Mechanical Engineering, Colorado State University, Fort Collins, Colo
    • ,
  • Kartik Sundareswaran, PhD

      Affiliations

    • Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Ga
    • ,
  • Diane de Zelicourt, MS

      Affiliations

    • Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Ga
    • ,
  • Kerem Pekkan, PhD

      Affiliations

    • Carnegie Mellon University, Pittsburgh, Pa
    • ,
  • Kevin Whitehead, MD, PhD

      Affiliations

    • Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pa
    • ,
  • Shiva Sharma, MD

      Affiliations

    • Pediatric Cardiology and Pediatrics, Lawrenceville, Ga
    • ,
  • Kirk Kanter, MD

      Affiliations

    • Emory University, Atlanta, Ga
    • ,
  • Mark A. Fogel, MD

      Affiliations

    • Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pa
    • ,
  • Ajit P. Yoganathan, PhD

      Affiliations

    • Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Ga

Article Outline

CTSNet classification: 20, 21, 26

 

We thank Kestelli and colleagues for their letter on this important topic. Fontan failure1, 2—defined here as poor prognosis after the Fontan operation—may occur at either an early or a late stage. Most late failures are in older patients with the classic atriopulmonary connection, with problems including arrhythmias, thromboembolism, heart failure, and pulmonary venous blockage. Early failures include arteriovenous malformations and protein-losing enteropathy, occurring mostly in patients with a total cavopulmonary connection. Heart failure appears eventually if no other failure mode manifests. These varying failure modes clearly show that the problem is complex, multifactorial, and still unfolding as more and more patients who underwent total cavopulmonary connection in the mid 1990s are now reaching adulthood. Even though all these patients have a single-ventricle physiology that is inherently preload limited with increased afterload,3 it is not yet clear whether preload limitation is the only cause. There are other independent factors (quality of connection, afterload, underlying congenital defect).

The specific modes of failure for a given patient depend on the severity of the underlying congenital heart defect, efficacy of the palliative approach chosen, and the health and composition of the interacting organ system, including the lungs and abdominal viscera. We have just begun a National Institutes of Health–funded predictive study to help determine the specific criteria for efficient management of these patients. For instance, patients in whom the hepatic flow return is biased toward a single lung may have arteriovenous malformations develop. Those with a highly energy-dissipating total cavopulmonary connection may have decreased preload, poor exercise tolerance, or high central venous pressure, leading to protein-losing enteropathy or heart failure. There is no predictive model currently available that can determine the precise contributors to and mechanisms of failure in a given patient, even when all hemodynamic information is available. We hope that our ongoing research will provide more definite answers to these questions in the coming years.

In the final analysis, for many patients with Fontan circulation, survival into the 4th or 5th decade may require innovative solutions, such as that proposed by Kestelli and associates.4 There are many concerns regarding the proposed solution, however, which may be trading one problem for many others. The proposed solution is energy neutral (energy available to drive the circulation is still the same, although it is used differently) but requires the single ventricle to pump significantly more volume to maintain the same cardiac output, thus decreasing net cardiac output. The theoretic gains in pulsatility and pulmonary vascular resistance must be balanced by the risks of low cardiac output, ventriculotomy, and thrombosis related to the valves in the pulmonary circuit. Nevertheless, these are just theoretic predictions, and detailed in vitro and in vivo studies are necessary to assess the true efficacy of this and other novel solutions. Venous and mechanical supports that provide an additional energy source are being studied through progressing animal models and may offer the best hope for some patients.5

Back to Article Outline

References 

  1. Huddleston CB. The failing Fontan: options for surgical therapy. Pediatr Cardiol. 2007;28:472–476
  2. Khairy P, Fernandes SM, Mayer JE, Triedman JK, Walsh EP, Lock JE, et al. Long-term survival, modes of death, and predictors of mortality in patients with Fontan surgery. Circulation. 2008;117:85–92
  3. Senzaki H, Masutani S, Ishido H, Taketazu M, Kobayashi T, Sasaki N, et al. Cardiac rest and reserve function in patients with Fontan circulation. J Am Coll Cardiol. 2006;47:2528–2535
  4. Kestelli M, Emrecan B, Lafci B, Ozsöyler I, Yilik L, Ozbek C, et al. A pulmonary ventricle system producing pulsatile pressure in single ventricle: experimental model. Braz J Cardiovasc Surg. 2006;21:324–327
  5. Myers CD, Boyd JH, Presson RG, Vijay P, Coats AC, Brown JW, et al. Neonatal cavopulmonary assist: pulsatile versus steady-flow pulmonary perfusion. Ann Thorac Surg. 2006;81:257–263

PII: S0022-5223(10)00211-4

doi:10.1016/j.jtcvs.2010.02.028

Refers to article:

  • Fontan hemodynamics: What is the problem?

    Mert Kestelli, Ismail Yurekli, Ali Gürbüz
    The Journal of Thoracic and Cardiovascular Surgery June 2010 (Vol. 139, Issue 6, Page 1673)

The Journal of Thoracic and Cardiovascular Surgery
Volume 139, Issue 6 , Pages 1673-1674, June 2010

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