Cardiac Recovery During Continuous-Flow Left Ventricular Assist Device Support

Abstract

In this issue of Circulation, Birks et al 1 report their recent experience using the combination of continuous-flow (CF) circulatory support and pharmacological therapy to treat advanced heart failure in patients requiring left ventricular assist device (LVAD) support. Thirty-three patients underwent HeartMate II (HMII) LVAD implantation at Harefield hospital during the 3-year study period. Twenty-three patients (70%) with nonischemic cardiomyopathy were considered appropriate for the recovery protocol at the time of HMII LVAD implantation, and 20 patients (61%) who survived LVAD implantation formed the study cohort. With their strategy of aggressive neurohormonal blockade (phase I) followed by high-dose clenbuterol (phase II), 12 (60%) of the study cohort met criteria for LVAD explantation, and all 10 (50%) who survived the perioperative period demonstrated sustained recovery over 56 to 1112 days of follow-up. Therefore, 30% of all patients and 43% of all nonischemic patients undergoing HMII implantation could be managed to long-lasting recovery. In an era in which transplant waiting times have blurred the distinction between bridge-totransplant and destination therapy for some patients, this single-center experience is intriguing and offers hope for a new strategy for select patients supported with CF LVADs. Article see p 381 Reports in the literature regarding rates of cardiac recovery during pulsatile LVAD support are quite varied (Table 1). The Columbia University group reported a 1% rate of sustained cardiac recovery in 111 patients with both ischemic and nonischemic etiology of heart failure. 2 In contrast, the German Heart Institute reported that 13% of patients with nonischemic heart failure demonstrated sustained recovery (minimum follow-up of 36 months) after LVAD explantation. 3 The LVAD Working Group was the first multicenter, prospective initiative to study recovery.4 Sixty-seven LVAD patients (only 1 CF LVAD) with both ischemic and nonischemic causes underwent serial echocardiograms at reduced flow to seek recovery. Six percent of the whole cohort and 7% of all nonischemic patients could undergo LVAD explantation. None of these reports described the consistent use of pharmacological therapy during LVAD support, and it was not until the first Harefield recovery study 5 that data regarding combined pharmacological and mechanical support were available. In the first Harefield study, 15 LVAD patients (1 CF LVAD) received maximal doses of heart failure medications, followed by high-dose clenbuterol. All patients had a nonischemic etiology, and most (80%) had heart failure for 6 months. The authors reported that 75% of patients receiving clenbuterol could undergo LVAD explantation and 46% of all patients with nonischemic heart failure presenting for LVAD could be managed successfully to recovery in this way. These data from Harefield represented the most successful reported recovery strategy to date, and prompted a multicenter study in the United States (to replicate the Harefield recovery protocol) called the Harefield Recovery Protocol Study (HARPS). HARPS has now completed enrollment of 17 patients with the HMI pulsatile LVAD, 13 of whom received both maximal neurohormonal blockade and high-dose clenbuterol. Results from the US HARPS study will be presented in the near future. With the approval of the HMII LVAD for both bridge-to