Abstract
We conducted chronic experiments to determine how to treat profound biventricular failure systematically with ventricular assist devices (VADs) and to analyze the factors that affect prognoses for this condition. Anoxic arrest was induced in ten goats by aortic cross-clamping under normothermic conditions (38.5° C) for 30 (n= 3), 45 (n= 1), and 60 (n= 6) minutes. A left ventricular assist device (LVAD) was implanted in eight animals, and a biventricular assist device (BVAD) was used in two. Three goats — two of which had undergone anoxic arrest for 30 minutes and one for 60 minutes — whose right atrial pressure (RAP) was approximately 18 mm Hg during the acute stage, recovered in two to three weeks, and the pumps were successfully removed. Pathological findings in these animals showed scattered areas of surviving myocardium, with connective tissue replacing the degenerated myocardium. The remaining five LVAD goats required higher RAPs to maintain circulation and died from various causes. Maintaining circulation without volume loading, even in the presence of arrhythmias, was easier with the BVAD. One BVAD animal that underwent 45 minutes of anoxic arrest recovered from right ventricular failure, and the right pump was removed. The second goat (anoxic arrest, 60 min) on the BVAD failed to recover. Autopsy of the myocardium revealed a thin ventricular wall. Our studies show that the use of VADs allows time for a failing heart to recover, but the potential for healing is affected by the severity of myocardial damage prior to VAD application. We believe that although LVADs can maintain circulation with high RAPs, the use of BVADs might be more beneficial for maintaining systemic organ function in cases of persistent biventricular failure.
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