Hypoplastic left heart syndrome: consensus and controversies in 2007

Variability in practice can be considered to foster clinical innovation, and allow for individualized therapeutic plans and independence of practitioners. The Institute of Medicine, however, has issued a report suggesting that variability in patterns of practice are "illogical", and should be avoided whenever possible. Perhaps nowhere in the field of congenital cardiac disease is variability in practice more apparent than in the management of hypoplastic left heart syndrome. This review assesses the variability in practice at a large number of centres that manage neonates with hypoplastic left heart syndrome, with an emphasis on practice before, during, and after the first stage of the Norwood sequence of operations. We also suggest changes in future strategies for research. In March, 2007, colleagues were contacted to respond to an internet-based survey using commercially available software (www.surveymonkey.com) to collect responses about the management practices for neonates with "straight-forward" hypoplastic left heart syndrome. No attempt was made to correlate management practices with any measures of outcome, as neither the practices themselves, nor the outcomes of interest, could be externally validated. Data is reported from 52 centers thought to manage over 1000 neonates with hypoplastic left heart syndrome on an annual basis. The first stage of the Norwood sequence was "recommended" to families by approximately five-sixths (86.5%) of the centres. No centre recommended primary cardiac transplantation, a "hybrid" approach, or non-intervention. In 7 centres (14.5%), it was reported that there was discussion of some or all of the above options, but ultimately the families decided upon the appropriate strategy. Most centres preferentially used antegrade cerebral perfusion (54%) in contrast to deep hypothermia with circulatory arrest (24%), albeit that 11% of centres used a combination of these techniques and in 9% the support strategy was based on surgeon preference. The source of flow of blood for the lungs following the first stage of reconstruction was also highly variable. Of the 51 centres that responded to the question, 13 (25.5%) were participating in a multi-centric randomized clinical trial comparing the modified Blalock-Taussig shunt to the conduit placed from the right ventricle to the pulmonary arteries, the so-called "Sano" modification. Of the remaining 38 centres, 18 "usually" placed a conduit from the right ventricle to the pulmonary artery, 14 "usually" placed a modified Blalock-Taussig shunt, and at six centres, the decision was made "based upon the preference of the surgeon and/or the cardiologist". Similarly, significant variability in practice was evident in preoperative management, other surgical strategies, postoperative medical support, monitoring and discharge planning. Other than the randomized clinical trial of shunt type, no other medical or surgical management strategy was currently under investigation in a multi-centric or randomized trial in the centres who responded to the survey. The survey emphasises the extreme variability in our current practices for treatment of children with hypoplastic left heart syndrome. While there are some areas for which there is consensus in management, the majority of our practices are variable between and within centres. These results emphasize that large multicentric trials and registries are necessary to improve care, and to answer important clinical questions, emphasizing the need to shift from analysis of experiences of single centres to multi-centric and multi-disciplinary collaboration.