Use of venovenous extracorporeal membrane oxygenation and an atrial septostomy for pulmonary and right ventricular failure.

BACKGROUND

Right ventricular failure is a major contributor to morbidity and mortality on the lung transplant waiting list. This study was designed to evaluate the effectiveness of an atrial septostomy with venovenous extracorporeal membrane oxygenation (VV-ECMO) as a novel potential bridge to transplantation.

METHODS

Adult sheep (58±3 kg; n=12) underwent a clamshell thoracotomy and instrumentation to measure all relevant pressures and cardiac output (CO). Sheep with tricuspid insufficiency (TI [n=5]) and without tricuspid insufficiency (ØTI [n=7]) were examined. After creation of a 1-cm atrial septal defect and initiating VV-ECMO, the pulmonary artery (PA) was banded to allow progressive reduction of pulmonary blood flow, and data were collected.

RESULTS

The CO in both groups remained unchanged from baseline at all pulmonary blood flow conditions. With TI, the CO was 5.1±1.2 L/min at baseline versus 5.1±1.2 L/min with a fully occluded PA (p=0.99). For ØTI, the CO was 4.5±1.4 L/min at baseline versus 4.5±1.2 L/min with no pulmonary blood flow (p=0.99). Furthermore, CO was not affected by the presence of TI (p=0.76). Mean right ventricular pressures were significantly lower in the TI group (TI=20.2±11 mm Hg versus ØTI=29.9±8.9 mm Hg; p<0.00001). Right and left atrial mean arterial pressures were not different between both groups (p>0.5). Lastly, VV-ECMO maintained normal blood gases, with mean O2 saturations of 99% ± 4.1% in both groups.

CONCLUSIONS

Right to left atrial shunting of oxygenated blood with VV-ECMO is capable of maintaining normal systemic hemodynamics and normal arterial blood gases during high right ventricular afterload dysfunction.