Study comparing two surgeries for infant heart defect shows mixed results

Washington, Nov 16 (ANI): Scientists have found mixed results in the first head-to-head comparison of two surgeries for infants born with severely underdeveloped hearts - the most common severe heart birth defect.

One surgery worked better initially but was associated with more complications, and by 2 years of age the survival advantage had disappeared. It remains to be seen which will prove better over the long term.

Babies born with a critically underdeveloped left side of their hearts require three surgeries to correct the problem.

A portion of the first operation, the Norwood Procedure, includes a connection to deliver blood from the heart to the pulmonary arteries feeding the lungs so that blood can pick up oxygen.

There are currently two ways it can be done. The new modification of the Norwood utilizes a right ventricle to pulmonary artery (RV-to-PA) shunt to connect the functioning right ventricle to the pulmonary artery.

The traditional version uses a modified Blalock-Taussig shunt (MBTS), which connects the aorta (the major blood vessel delivering blood from the heart to the body) to the pulmonary artery.

In a 15-center trial by the Pediatric Heart Network, 555 infants (61 percent male, 73 percent Caucasian) were randomized to receive either the RV-to-PA shunt or MBTS procedure.

The researchers found that at 12 months, significantly more babies survived without requiring a heart transplant with the RV-to-PA shunt compared to the MBTS.

The RV-to-PA shunt had more complications, necessitating 240 interventions, for example, to make adjustments to the shunt or use balloons or stents to keep it open. Far fewer cardiovascular interventions were needed in the MBTS group, it was found.

Researchers also found that at an average of two years, the transplant-free survival advantage of RV-to-PA over MBTS had diminished and was no longer significant.

"Early results seem to favour the RV-PA shunt, but by two years there is no longer any survival advantage. It is still unknown which will turn out to be better over the long term," said Richard G. Ohye, M.D., lead author of the study and associate professor of surgery at the University of Michigan Medical School in Ann Arbor.

The research has been presented at the American Heart Association's Scientific Sessions 2009. (ANI)