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Effect of synchronous and asynchronous pulsatile flow during left, right, and biventricular bypass
D J Cohen1, M F Clem, M Luther
1Cardiothoracic Surgery Service, Brooke Army Medical Center, Ft. Sam Houston, Texas 78234.
Artificial Organs
|December 1, 1992
Summary
Biventricular assist devices (BIVAD) in asynchronous mode effectively reduce myocardial oxygen consumption (MVO2). Synchronous counterpulsation offers no benefit for reducing MVO2 or improving myocardial metabolism.
Area of Science:
- Cardiovascular Physiology
- Medical Device Technology
Background:
- Ventricular assist devices (VADs) support cardiac output, operating in asynchronous or synchronous modes.
- Optimizing VAD function is crucial for reducing myocardial oxygen consumption (MVO2) and improving cardiac recovery.
Purpose of the Study:
- To determine the optimal assist modes for VADs to minimize MVO2 and alter myocardial metabolism.
- To compare the efficacy of asynchronous versus synchronous modes in left ventricular assist devices (LVAD) and biventricular assist devices (BIVAD).
Main Methods:
- Twelve pigs were instrumented to measure MVO2 and myocardial lactate production (LACT).
- Six pigs received LVAD, and six received BIVAD.
- Experimental periods included control, asynchronous, and synchronous bypass, with coronary artery ligation to induce ischemia.
Main Results:
- Asynchronous BIVAD significantly reduced MVO2 compared to control (p < 0.05).
- LVAD and synchronous BIVAD modes did not significantly alter MVO2.
- Myocardial tissue ATP and lactate levels remained unaffected by any assist mode.
Conclusions:
- Biventricular assist in asynchronous mode is superior for reducing MVO2.
- Synchronous counterpulsation provides no discernible advantage in reducing myocardial workload or improving metabolic markers.
- For cardiac recovery, biventricular assist is recommended over univentricular assist, with asynchronous operation being optimal.