Abstract 4567: Functional Intraoperative Pulmonary Blood Flow Study is a Sensitive Predictor of Right Ventricular Pressure and Successful VSD Closure for Following Complete Uniforcalization in Patients with Pulmonary Atresia with Ventricular Septal Defect and Major Aortopulmonary Collaterals

OBJECTIVE: We hypothesized mean pulmonary artery (PA) pressure obtained from an intraoperative pulmonary flow study would better predict the ability to close the ventricular septal defect (VSD) and better predict postoperative right ventricular systolic pressure (RSVP) than classic anatomical parameters after complete uniforcalization in patients with pulmonary atresia, VSD, and major aortopulmonary collaterals. METHODS: Sixteen consecutive patients (median, 11 mo, range 2 mo – 16 yrs) underwent one-stage (75%) or staged (25%) uniforcalization between 1/03 and 8/07. Intraoperative functional pulmonary blood flow study was achieved by inserting an arterial cannula in a reconstructed central PA. Flow was increased to 2.5 L/min/m2 while measuring PA pressure. RVSP and systemic systolic pressure (SBP) were recorded after VSD closure. Total neopulmonary artery index (TNPAI) (MAPCA + native PA index), total incorporated pulmonary vascular segments, and pulmonary segment artery ratio (PSAR) (ratio of incorporated segment to 18) were analyzed. Spearman rank correlation and area under the receiver operator characteristics curve (ROC-AUC) were used. RESULTS: The mean PA pressure on flow study was 21.8+/−6.2 mmHg (range, 11–31). Three patients had a pressure of > 30 mmHg. The VSD was closed in 14 (87%). One patient with flow study mean PA pressure of 25 mmHg had suprasystemic RVSP and underwent intraoperative VSD fenestration. One with a flow study mean PA pressure of 30 mmHg had a prospective fenestrated VSD patch placed. There is a weak negative correlation between TNPAI and the flow study PA pressure (rho=−0.4, p=0.12). The flow study mean PA pressure was correlated with post-repair RVSP (rho=0.72, p=0.0027), and with RVSP/SBP ratio (rho=0.67, p=0.0063). TNPAI, total incorporated segments, and PSAR were not correlated with the postoperative RVSP or RVSP/SBP ratio. Flow study mean PA pressure had the highest sensitivity in predicting VSD closure: ROC-AUC (0.82) vs. TNPAI (0.46), pulmonary segment (0.64), and PSAR (0.64). CONCLUSIONS: Intraoperative pulmonary flow study predicted the ability of VSD closure better than total incorporated segments, TNPAI, and PSAR. Flow study mean PA pressure highly correlated with postoperative RVSP and RVSP/SBP ratio.