Abstract 19213: Establishment of Mechanically-Assisted Primary Bidirectional Cavopulmonary Shunt in Neonates and Infants: An Acute Human Pilot Study

Abstract

Background: One year survival for stage 1 palliation in hypoplastic left heart syndrome (HLHS) is 69%. We hypothesized that primary ‘in-series’ palliation (neonatal bidirectional cavopulmonary shunt - BCPS) with mechanical assist would provide more stable physiology. This is the first human study of an acute intraoperative BCPS model. Methods: Two types of intraoperative, tubing configured, pump-assisted BCPS circulations [superior vena cava (SVC) to pulmonary artery (PA) pump assist at stage I Norwood, and SVC to right atrium (RA) pump with oxygenation at stage II BCPS] were established in the operating room for 20 minutes at the time of modified ultrafiltration (Figure 1A). Hemodynamics and cerebral blood flow were continuously recorded. Arterial and venous blood gases were analyzed every 5-10 minutes. Results: All six patients (3 in each group) completed 20 minutes of mechanical support without hemodynamic compromise. In the SVC-PA pump assist (n=3), the pump generated effective pulmonary blood flow of 335+/-53ml/min while the BT shunt was occluded. Compared to Norwood physiology, the SVC-PA pump-assisted BCPS had a higher mean arterial pressure (median 33 vs. 44 mmHg, p=0.02), lower central venous pressure (CVP) (12 vs. 10 mmHg, p=0.03), and higher cerebral perfusion pressure (33 vs. 46 mmHg, p=0.01) (Figure 1B). In the SVC-RA oxygenation assist (pump and oxygenator assisted BCPS), the pump generated blood flow of 536+/176ml/min with oxygenation. Compared to baseline BCPS physiology, SVC-RA oxygenation-assisted BCPS had a lower CVP (14 vs. 7 mmHg, p=0.05). Conclusion: The study demonstrates the physiologic feasibility of mechanically assisted neonatal in-series single ventricle circulation. Both assist systems attained equivalent or better hemodynamics, stable ventilation and oxygenation, and a more favorable cerebral perfusion profile. This human proof of concept study raises the possibility of a potential paradigm shift for the treatment of HLHS.