An institutional experience with the bidirectional cavopulmonary shunt: do we know enough about it?

Abstract

AbstractBackgroundThe bidirectional cavopulmonary shunt has become a mainstay in the palliation of patients with a functionally single ventricle. Despite its usefulness, there are a number of concerns following its construction, including issues of timing, the development of pulmonary arteriovenous fistulas, and growth of the pulmonary arteries.MethodsBetween January 1990 and April 1996, we constructed a bidirectional cavopulmonary shunt in 123 patients. Median age at surgery was 9.4 months, and ranged from 24 days to 43 years. In 25 patients (20%), it was the first operative procedure. An auxiliary source of pulmonary blood flow was included in 72 patients (58%).ResultsSix patients (4.9%) died in the early postoperative period, and the overall early rate of failure (death or take-down) was 8.1%(n=10). By multivariate analysis, longer bypass time (p=0.012), age less than 1 month (p=0.03), and higher pulmonary vascular resistance (p = 0.043) were significant. Early reoperation was performed in 11 other patients to decrease (n=8) or increase (n=3) the amount of pulmonary blood flow. Early survivors were followed for a median of 15 months (range: 1 to 48 months), during which time 5 patients died and a Fontan circulation was completed in 30. Including early and late mortality, actuarial survival rates at 1 and 2 years were 91% and 88%, respectively. Among hospital survivors, the only significant predictor of poorer survival by Cox regression was age less than 2 months at the time of the initial cavopulmonary shunt (p=0.02). Atrioventricular valvar regurgitation was decreased after construction of the cavopulmonary shunt in 17 of the 28 patients (61%) in whom echocardiographic data were available to compare preoperative and postoperative status.ConclusionsThe bidirectional cavopulmonary shunt is a useful procedure in the early or intermediate term management of patients with a functionally univentricular heart. Much remains to be learned, nonetheless, about this unique physiologic system. The role of accessory pulmonary blood flow remains unclear, as does the use of the shunt as long-term palliation. Pulmonary arteriovenous fistulas are a serious concern, especially in young patients with heterotaxy syndrome (isomeric atrial appendages).