INFLUENCE OF COMPETITIVE PULMONARY BLOOD-FLOW ON THE BIDIRECTIONAL SUPERIOR CAVOPULMONARY SHUNT - A MULTIINSTITUTIONAL STUDY

Background It is common practice to interrupt all alternative sources of pulmonary blood flow (''competitive flow'') at the time of a bidire ctional superior cavopulmonary anastomosis (BCPA), although the merits of this have not been systematically studied. Methods and Results We reviewed the early and medium-term clinical and hemodynamic findings i n 108 consecutive patients 3 weeks to 25 years old (median, 1.9 years) undergoing BCPA at one of three institutions. Preoperatively, pulmona ry blood flow was dependent on antegrade ventricular flow (n=50), syst emic-to-pulmonary shunts (n=33), or mixed sources (n=25). Postoperativ ely, competitive sources of pulmonary blood flow were left patent in 4 3 of 108 patients (40%). There were four early (3.7%) and four late de aths, none related to persistence of competitive flow. After BCPA, pat ients with competitive how had significantly higher systemic oxygen sa turations at 1 hour (85% versus 79%), 24 hours (84% versus 78%), and a t hospital discharge (84% versus 78%) and required a shorter period of artificial ventilation (median, 9 versus 24 hours) and intensive care (median, 2 versus 4 days). Oxygen saturations at late follow-up (medi an, 2.8 years; range, 1 to 7) did not differ (83% versus 82%). No pati ent developed pulmonary arteriovenous malformations. Conclusions Compe titive flow is well tolerated in the short and medium term after BCPA, and early postoperative systemic oxygen saturations are improved. The long-term influence of competitive flow on pulmonary arterial growth, arteriovenous malformation development, acid ventricular function war rants investigation.