Impact of differential right-to-left shunting on systemic perfusion in pulmonary arterial hypertension.

摘要: Objectives This study aimed at identifying the ideal right-to-left shunt-fraction to improve cardiac output (CO) and systemic perfusion in pulmonary arterial hypertension (PHT). Background Atrial septostomy (AS) has been a high-risk therapeutic option for symptomatic drug-refractory patients with PHT. Results have unpredictable due limited knowledge of optimal shunt-quantity. Methods In nine dogs, an 8-mm shunt-prosthesis was inserted between superior vena cava (SVC) left atrium. With artery (PA) banding, mean (±SEM) systolic right ventricular pressure increased from 37 ± 1 mm Hg baseline 44 (moderate PHT, P = 0.005) 50 2 (severe < 0.001). Shunt-flow adjusted by total (forcing all flow through shunt) or partial occlusion SVC clamping shunt. Caval-, shunt-, aortic-flow were measured ultrasonic flow-probes. Blood gases drawn aortic root PA. Results At severe shunt-flow 11 1% CO (253 90 mL/min) significantly 25% (1.8 0.1 2.4 0.2 L/min, causing increase oxygen delivery index (DO2I) 23% (309 23 399 32 mL/min/m2, 0.035). Arterial O2-saturation did not change until 18 2% exceeded, drop 96 84 4% (P 0.013). At moderate DO2I any shunt-flow. Conclusions In 11% represented shunt-fraction. Augmentation compensated declined shunting improved DO2I. In AS is less promising. © 2012 Wiley Periodicals, Inc.