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| |  Right Ventricle-to-Pulmonary Artery Shunt Offers Mixed Results for Infants With Underdeveloped Hearts: Presented at AHA By Deborah Brauser ORLANDO, Fla -- November 16, 2009 -- More babies born with an underdeveloped heart survive to 12 months after undergoing the Norwood Procedure using a right ventricle-to-pulmonary artery (RV-to-PA) shunt than those who undergo the more traditional modified Blalock-Taussig shunt (MBTS), according to a new randomised study. However, the differences in transplant-free survival diminish after an average of 2 years. The results of the Single Ventricle Reconstruction Trial were presented here on November 15 at the American Heart Association (AHA) Scientific Sessions 2009. “Roughly 50% of surgeons use each type of shunt procedure during single ventricle repair, but we don’t truly know which is better because there has never been a comparison study before,” reported study chair Richard G. Ohye, MD, University of Michigan Congenital Heart Center, Ann Arbor, Michigan, during his podium presentation of the study, which won the Outstanding Research Award on Cardiovascular Disease in the Young. In fact, there has never before been a multicentre, randomised clinical trial performed in congenital heart surgery, said Dr. Ohye. “So this trial sets a new standard for using evidence-based medicine to evaluate new procedures in congenital heart surgery.” During his presentation, Dr. Ohye reported that babies born with a critically underdeveloped left side of their hearts require a series of corrective surgeries. “The Norwood Procedure makes up a portion of the first operation and includes a connection to deliver blood from the heart to the pulmonary arteries feeding the lungs so that blood can pick up oxygen.” Currently, there are 2 ways to perform the Norwood Procedure: the RV-to-PA shunt to connect the functioning right ventricle to the pulmonary artery or the traditional MBTS, which connects the aorta to the pulmonary artery. In this study, 555 infants (61% male, 73% white) were enrolled from May 2005 to July 2007 at 15 centres through the Pediatric Heart Network and randomised to receive either a RV-to-PA (n = 276) shunt or the standard MBTS (n = 279) Results for the primary endpoint, which was transplant-free survival at 12 months, showed that significantly more of the babies who had the RV-to-PA shunt survived, 74% versus 64% for those undergoing MBTS (P = .01). However, the RV-to-PA shunt group had more complications, leading to 240 interventions. Only 183 cardiovascular interventions were needed in the MBTS group (P = .006). In addition, after annual follow-ups of all patients, the investigators found that at an average of 2 years, the survival advantage had decreased to 68% for the RV-to-PA group and was no longer significantly different from the 62% survival rate for the MBTS group. (P = 0.14). “Early results seem to favour the RV-PA shunt, and it was clearly superior to the MBTS group. But by 2 years, there is no longer any survival advantage,” said Dr. Ohye in a press release. “It is still unknown which will turn out to be better over the long term.” After the presentation, Dr. Ohye said that ongoing surveillance of these children as they grow and undergo their final surgical procedure “will be very important to determine the proper roles of these shunts. We look forward to following these kids further.” Funding for this study was provided by the National Heart, Lung and Blood Institute. [Presentation title: Outcomes of the Norwood Operation in Infants Randomized to a Modified Blalock-Taussig Versus Right Ventricle-to-Pulmonary Artery Shunt: The Pediatric Heart Network Single Ventricle Reconstruction Trial. Abstract 1815]
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