Invited commentary

Abstract

This paper describes the current approach to the surgical treatment of hypoplastic left heart syndrome (HLHS) at Loma Linda University Children's Hospital (LLUCH), the institution that pioneered the use of cardiac transplantation as the primary therapy for HLHS. Several years ago, Checchia and associates recognized that the ongoing shortage of donor hearts and the recent reports of improved results for the staged surgical management of HLHS mandated consideration of a new strategy for management of HLHS syndrome at LLUCH. In August 1999, the authors implemented a new algorithm for decision-making in the treatment of HLHS. Operative risk was predicted based on a weighted score derived from six variables. The Norwood approach was then recommended for “low-risk” patients and cardiac transplantation was recommended for “high risk” patients. All Norwood patients received a modified Blalock-Taussig shunt and circulatory arrest was avoided. In addition, a postoperative care protocol based on multiple reports in the literature suggesting that an aggressive monitoring and treatment regimen can result in improved short-term survival following the Norwood-type operation was utilized. Implementation of the treatment protocol was associated with dramatic improvement in outcomes for the stage I procedure at LLUCH, and the decision-making algorithm appeared to predict the relative risk of the Norwood procedure for individual patients at LLUCH. This very interesting report has a number of limitations. There were a small number of patients in each group and they were not randomized. Although the recommended treatment plan was based on the proposed algorithm, many families did not opt for the recommended therapy. Since the study compares an historic control group to a more modern treatment protocol, there is a possibility that a learning curve played a role in the improved results in the Norwood group. This concern may be diminished by the fact that 88% of all the operations were performed by the same surgeon. The authors did not explore or discuss the role of the right ventricle to pulmonary artery conduit in the surgical management of HLHS. Some reports suggest that utilizing a right ventricle to pulmonary artery conduit as the source of pulmonary artery blood flow during a Norwood-type stage I reconstruction may reduce the early postoperative risk of death. Finally, the report does not address the potential utility of a careful follow-up and treatment protocol after hospital discharge following the Norwood procedure. The authors are to be commended for their willingness to publish their earlier results with palliative surgery for HLHS as a “control group.” The dramatic improvement in 48-hour and 30-day survival clearly validates the utility of a tightly controlled postoperative treatment regimen following palliative surgery for HLHS. This paper also suggests that a treatment algorithm can be developed, which sorts patients into high and low risk subsets. Additional experience with the decision-making algorithm should permit refinements that will improve the accuracy of the scoring system, and convince parents of the validity of the predictions derived from the score. While the shortage of donor hearts makes transplantation an unrealistic primary option for most babies born with HLHS, the outcome data in this report indicate that cardiac transplantation still has a role in the primary treatment of some infants born with HLHS. The present study suggests that an algorithm can be devised that predicts the relative risks of two different approaches to the primary treatment of HLHS. The right ventricle to pulmonary conduit approach represents a third option that was not explored in this study. Longer term follow-up will be necessary to determine the effect of the right ventricle to pulmonary artery conduit approach on pulmonary artery growth and right ventricular function (including late arrhythmias). Ultimately, a multicenter study may be necessary to determine the optimal initial treatment strategy for HLHS, since it is probable that all three approaches will have merit as treatment options in individual patients identified to have specific risk factors, as defined by a comprehensive preoperative evaluation protocol.