[Problems in patients with use of a ventricular assist device]

The purpose of the present study was to review the results obtained in patients with a ventricular assist devices (VAD) in our hospital, and to discuss various problems concerning a VAD use, such as indications, right ventricular failure, and evaluation of cardiac function. Fourteen VADs were applied to 11 patients for left ventricular assist, including two for right ventricular assist and for one as biventricular assist with a VAD in the left and a biopump in the right. The clinical diagnoses of the patients were as follows: 10 ischemic heart disease, two valvular disease, one acute aortic dissection, and one corrected transposition of the great arteries. VADs were indicated in 11 patients because of difficulty in weaning from cardiopulmonary bypass (CPB), and in three patients because of cardiogenic shock after discontinuing CPB. Among the 14 patients, 11 had an effective VAD, six were successfully weaned from a VAD, and two survived. The VAD was ineffective due to uncontrollable bleeding and improper indications for the device, as in applying a one-sided heart assist when a biventricular assist was necessary. In spite of an effective VAD, five patients could not be weaned from VAD because of brain damage, sepsis, and hypoxia. After removing a VAD, four patients died; one due to mediastinitis, two due to respiratory failure, and one due to low output syndrome. All the four patients had renal failure followed by multi-organ failure finally, because of prolonged CPB time. The CPB time was shorter among the long survivors than in others. Cardiac function during assist and the weaning probability from a VAD were evaluated not only by the so-called on-off test, but also by transesophageal Doppler echocardiography. Ventricular wall motion and pulmonary venous flow pattern were analyzed by transesophageal Doppler echocardiography. The pattern of monophasic forward flow in the pulmonary vein was associated with reduced wall motion during deteriorated cardiac function, while the flow pattern became biphasic as cardiac function recovered. From these results, we concluded as follows: 1. Early decisions as to whether VAD is indicated are important. 2. A right VAD should be considered in cases with biventricular failure, during left ventricular assist, if right atrial pressures elevated more than 18 mmHg constantly. 3. The evaluation of cardiac function by transesophageal Doppler echocardiography is useful for making decisions as to wean patients from a VAD.