Left Versus Biventricular Assist Devices in Cardiac Arrest
Maintaining adequate organ perfusion during cardiac arrest remains a challenge, and various assist techniques have been evaluated. We assessed whether a right ventricular impeller assist device (RVAD) in adjunct to a left ventricular impeller assist device (LVAD) is beneficial. Twenty anesthetized pigs were randomized to maximized circulatory support by percutaneously implanted left- or biventricular assist device(s) during 30 minutes of electrically induced ventricular fibrillation followed by three attempts of cardioversion. Continuous hemodynamic variables were recorded. Cardiac output and myocardial, cerebral, renal, and ileum mucosa tissue perfusion were measured with fluorescent microspheres, and repeated blood gas analyses were obtained. With biventricular support, an increased LVAD output was found compared with left ventricular (LV) support; 3.2 ± 0.2 (SEM) vs. 2.0 ± 0. 2 L/minute just after start of ventricular fibrillation, 3.2 ± 0.1 vs. 2.0 ± 0.1 L/minute after 15 minutes, and 3.0 ± 0.1 vs. 2.1 ± 0.1 L/minute after 30 minutes of cardiac arrest (pg < 0.001). Biventricular support also increased aortic and LV pressure, in addition to end-tidal CO2. Tissue blood flow rates were increased for most organs with biventricular support. Blood gas analyses showed improved oxygenation and lower s-lactate values. However, myocardial perfusion was degraded with biventricular support and return of spontaneous circulation less frequent (5/10 vs. 10/10; p = 0.033). Biventricular support was associated with high intraventricular pressure and decreased myocardial perfusion pressure, correlating significantly with flow rates in the LV wall. A transmural flow gradient was observed for both support modes, with better maintained subepicardial than midmyocardial and subendocardial perfusion.