Additional pulmonary blood flow with the bidirectional Glenn anastomosis: does it make a difference?

Background: The bidirectional cavopulmonary shunt has become a mainstay in the palliation of patients with a functional single-ventricle heart. However, there remain a number of unresolved issues regarding this procedure, many of which concern the response of the pulmonary vasculature to this unique circulatory physiology. Among the issues of debate are the role and effects of an additional source of pulmonary blood flow.
Methods: Between January 1990 and April 1997, 160 patients underwent bidirectional cavopulmonary anastomosis. Median age at operation was 7.8 months, and age ranged from 24 days to 43 years. An additional source of pulmonary blood flow was included in 93 patients (58%). A retrospective review of our experience with this cohort was performed with a focus on the role of additional pulmonary blood flow.
Results: Eight patients (5%) died in the early postoperative period, and the overall early failure rate (death or take-down) was 7.5% (n=12). Eleven other patients underwent early reoperation to decrease (n=8) or increase (n=3) the amount of pulmonary blood flow. Early survivors were followed up for a median of 23 months, during which time 5 patients died and 30 patients underwent Fontan completion. Including early and late mortality, actuarial survival rates at 1 and 2 years were 91% and 88%, respectively.
Conclusions: The bidirectional cavopulmonary shunt is a useful procedure in the early or intermediate-term management of patients with a functional univentricular heart. However, there is much still to be learned about this unique physiologic system. The role of accessory pulmonary blood flow remains unclear, as does the use of the bidirectional cavopulmonary shunt as long-term palliation. Pulmonary arteriovenous fistulas are a serious concern, especially in young patients with heterotaxy syndrome.