SAN FRANCISCO – There is no consensus among experts on the optimal surgical approach to repair neonatal hypoplastic left heart syndrome, if a series of consecutive talks at the annual meeting of the American Association for Thoracic Surgery is any indication.
Dr. David J. Barron is a proponent of the placement of a stage 1 right ventricle–pulmonary artery (RV-PA) conduit (Circulation 2003;108[suppl. 1]:II155-60); Dr. J. William Gaynor prefers a stage 1 Blalock-Taussig (BT) shunt; and Dr. Mark E. Galantowicz advocates a hybrid stage 1 procedure.
Dr. Emile A. Bacha tied all these strategies together in a differential approach to management of neonates with hypoplastic left heart syndrome. There may be no one answer; local factors such as surgeon experience or medical center volume can impart significant difference on outcomes, Dr. Bacha said. His bias, in general, is to use the BT shunt for aortic stenosis and the RV-PA conduit for aortic atresia, and to reserve the hybrid approach for high-risk patients. Dr. Bacha is director of the congenital and pediatric cardiac surgery at the Morgan Stanley Children’s Hospital of New York–Presbyterian in New York City.
The surgeons provided the following overview:
• Stage 1 RV-PA conduits. "If you have any condition where there are three different ways to do the same operation, [it indicates that] we are still looking for the right way of doing it. What is important is trying to find the right operation for the right patient," said Dr. Barron, a consultant cardiac surgeon at Birmingham (England) Children’s Hospital.
"It’s all about diastole" with the RV-PA conduit, Dr. Barron said. The maintenance of diastolic pressure is a benefit with RV-PA, compared with the classic Norwood shunt, he added. "When you turn off the shunt in the OR, you get dramatic drop with Norwood where both systolic and diastolic drop. With the RV-PA, the systolic pressure drops but the diastolic pressure is maintained. This facilitates "more of cardiac output to systemic circulation, where you want it to be."
"We’re in an era of evidence-based medicine, and it’s not always easy to find class I evidence in congenital heart disease. The strategy sounds good, but can we actually prove it is better?" Dr. Barron asked. He pointed to a multicenter comparison of 549 infants who were randomized to a modified BT or PA-RV shunt; the study revealed a 10% survival advantage for the PV-RA patients at 1 year (N. Engl. J. Med. 2010:362:1980-92).
A disadvantage of the PV-RA shunt was more catheterization lab interventions (41%, vs. 26% for the modified BT shunt). In addition, the transplantation-free survival advantage was no longer significant after 12 months, he said.
• Stage 1 BTshunts. "We really need to focus on how well these children do over the long run," said Dr. Gaynor, attending cardiothoracic surgeon at the Children’s Hospital of Philadelphia (CHOP).
"Most of the benefit of the RV-PA is in the early interstage period," Dr. Gaynor said. He pointed out that transplant-free survival was not statistically different in the New England Journal of Medicine study at a mean of 32 months’ follow-up.
Dr. Bacha noted that with both speakers using the same study to argue their points," it may be time for a new trial."
Dr. Gaynor suggested that he will remain a proponent of the modified BT shunt until sufficient, long-term evidence supports survival and other advantages with the use of the RV-PA. The RV PA may have some advantages for high-risk subgroups, but more data are needed, he said.
Likewise, an examination of stage 1 reconstruction at CHOP with either the RV-PA or a modified BT shunt showed no significant difference on overall survival, Dr. Gaynor said. (Ann. Thorac. Surg. 2005:80:1582-90). Interestingly, timing made a difference: Patients with the modified BT shunt had significantly higher morbidity during the interstage period, but those with an RV-PA conduit demonstrated a trend toward increased death or transplant for heart failure after stage 2 reconstruction.
• Hybrid stage 1 surgery. "I am in favor of hybrid stage 1 for initial palliation for hypoplastic left heart syndrome. Hybrid stage 1 has at least equivalent results to traditional approaches in standard-risk patients," said Dr. Galantowicz, chief of cardiothoracic surgery at Nationwide Children’s Hospital in Columbus, Ohio.
A hybrid stage 1 can effectively bridge a child to recovery and can salvage a child who was not diagnosed at birth, Dr. Galantowicz said.
There is some evidence that a hybrid approach is less costly overall, compared with placement of a modified BT shunt (Ann. Thorac. Surg. 2009;87:1885-92).