Management of patients with aorto-pulmonary collaterals

Stanford University, California, USA
Frank L. Hanley

Since July 1992 we have prospectively applied a complex and formal surgical protocol to patients with major aortopulmonary collaterals (MAPCAs). The protocol is designed primarily to achieve the largest, healthiest pulmonary microvascular bed possible. Priorities include early removal of all MAPCAs from the systemic circulation, and complete unifocalization using native tissue anastomoses. Intracardiac repair is performed as early as possible, but only when low right ventricular pressure is assured.
We reviewed 307 consecutive patients. There were 3.8 ± 1.4 MAPCAs per patient. The median diameter of the central pulmonary arteries (PAs) was 1.5 mm. PAs were absent in 23%. Cardiac morphology was pulmonary atresia with VSD in 94%. Median age at first surgery was 8 months. Initial operation was complete bilateral unifocalization via sternotomy in 85%. Intracardiac repair was also achieved at initial operation in 56%, and in 83% within 2 yrs. Alternative initial operations, such as creation of main PA to aortic anastomosis, or staged unifocalization via thoracotomy, were performed in a minority of patients, according to strict morphologic and physiologic criteria. These criteria will be discussed in detail. Early mortality was 9.7% in the first half of the experience, and 2.0% in the second. In patients achieving intracardiac repair, the median RV/LV pressure was 0.44 in the first half, and 0.35 in the second half. Late follow up was 81% complete up to 12 yrs with 6.3% mortality. Kaplan-Meier survival at 1, 5, and 10 yrs was 91%, 86%, and 86%. RV/LV pressure did not rise over time, and growth of unifocalized MAPCAs is well documented. Documented occlusion of unifocalized MAPCAs was rare.
Ongoing evaluation of the pulmonary vasculature with appropriate use of both surgical and interventional techniques is an important component of the overall management. Surgical creation of a single compartment pulmonary artery system that includes as many lung segments as possible and is achieved early in infancy promotes low pulmonary vascular resistance, allowing a high rate of intracardiac repair with low right ventricular pressure. Under this management, growth of both hypoplastic pulmonary arteries and MAPCAs keeps up with somatic development. Using current techniques surgical mortality for these complex operations is acceptable at 2%.