Low incidence of myocardial recovery after left ventricular assist device implantation in patients with chronic heart failure

Background-Mechanical, histological, and biochemical improvement has been d escribed in patients after left ventricular assist device (LVAD) support. E xplantation of the LVADs without heart transplantation has been described i n selected patients who received this therapy as a bridge to transplantatio n. Methods and Results-A retrospective review of patients receiving a mechanic al bridge to transplantation at Columbia Presbyterian Hospital after July 2 1, 1991, was performed to determine the incidence of patients in whom the d evice was successfully explanted. From August 1, 1996, to February 1, 1998, we prospectively attempted to identify potential explant candidates by the use of exercise testing. During this time, we recruited 39 consecutive pat ients after insertion of the Thermo Cardiosystems vented electric device to participate in the following study. Approximately 3 months after device im plantation, a maximal exercise test with hemodynamic monitoring and respira tory gas analysis was performed with the LVAD in the automated mode. The el ectric device was interfaced with a pneumatic console such that the rate co uld be decreased to 20 cycles/min. Hemodynamic measurements were recorded a s the device rate was decreased. A repeat exercise test was then performed if the patient remained hemodynamically stable. A retrospective chart revie w of 111 LVAD recipients at our institution identified only 5 successful ex plant patients. Eighteen of the 39 patients were studied. Fifteen patients exercised with maximal device support. At peak exercise, (V) over dot o(2) averaged 14.5+/-3.6 mL.kg(-1).min(-1); LVAD flow, 8.0+/-1.3 L/min; Fick car diac output, 11.4+/-3.3 L/min; and pulmonary capillary wedge pressure, 13+/ -4 mm Hg. Seven patients remained normotensive and could exercise at a fixe d rate of 20 cycles/min. In these patients, peak (V) over dot o(2) declined from 17.3+/-3.9 to 13.0+6.1 mL.kg(-1).min(-1). In one of these patients, t he device was explanted. Conclusions-Significant myocardial recovery after LVAD therapy in patients with end-stage congestive heart failure occurs in a small percentage of pat ients. Most of these patients have dilated cardiomyopathy. Exercise testing may be a useful modality to identify those patients in whom the device can be explanted.