Prolonged circulatory maintenance with a left ventricular assist device during cardiac arrest

Summary

The occurrence of an intractable severe biventricular failure, ventricular fibrillation, or cardiac arrest during the use of a left ventricular assist device (LVAD) is a serious problem. The purpose of this study is to examine the feasibility of prolonged circulatory maintenance with an LVAD alone during cardiac arrest until heart transplantation is performed. After an LVAD was inplanted between the left atrium and aorta in 12 goats, ventricular fibrillation was induced. When pulmonary vascular resistance was in the normal range (less than 15 000 dynes.s.cm⁻⁵.kg), the circulation was well maintained with an LVAD alone as long as right atrial pressure was kept at 14–16 mmHg. Under such conditions, the flow fluctuated between 80 and 140 ml/kg/min depending on the animal’s demand, and the mean arterial pressure was kept above 80 mmHg. The goats behaved quite normally. However, pooling of pleural effusion was a serious problem in maintaining normal circulation for a prolonged duration. Maintenance of the total protein level above 6.0 g/dl could delay or prevent pooling of effusion. The longest survival period to date has been 38 days. When pulmonary vascular resistance is in the normal range, an LVAD alone during cardiac arrest will provide sufficient time to try a further treatment such as heart transplantation or total artificial heart replacement.