(P108) MYOCARDIAL RECOVERY AND SURVIVAL AFTER WEANING OF LEFT VENTRICULAR ASSIST DEVICE THERAPY IN PATIENTS WITH TOXIC AND NON-TOXIC CARDIOMYOPATHIES, A CANADIAN EXPERIENCE

Background: Left ventricular assist devices (LVAD) are increasingly used in advanced and refractory heart failure, mainly as a bridge to transplantation or as a destination therapy. LVAD unloading of the left ventricle (LV) can also promote myocardial recovery leading to improvement of the LV systolic function, allowing subsequent LVAD explantation. However, the parameters associated with LVAD weaning and the long-term outcomes of these patients are not well documented. The aim of this study was to assess the clinical and echocardiographic characteristics of weaned patients and to evaluate their event-free survival post-explantation.

METHODS AND RESULTS: We conducted a single-center retrospective study recruiting consecutive patients who underwent a second or third generation LVAD implantation at a Canadian cardiology center between November 2009 and October 2021. A total of 98 patients underwent an LVAD implantation at our institution during this period (Table 1). All patients were on guideline-directed medical therapy. Fourteen patients (14%) had significant LV recovery and were successfully weaned and explanted/decommissioned after a median support time of 309 days (range 55-595 days). Toxic cardiomyopathy, defined as an abuse of amphetamine ( n= 2), energy drink ( n=2 ) or mixed consumption (n= 6), was the most likely diagnosis for 10 of the weaned patients (71%). The LVEF was significantly higher (35% vs. 19%, p< 0.001) and the left ventricular end-diastolic diameter (LVEDD) was significantly smaller (51 mm vs. 60 mm, p=0.008) in weaned patients compared to non-weaned patients after 3 months of LVAD support (Figure 1). Myocardial recovery manifested by pump thrombosis in 4 of the 14 weaned patients (29%). After explantation, weaned patients were followed during a median time of 40 months (range 8-109 months). The mean LVEF was 44 +/- 6% at last follow-up and no patient had a LVEF below 35%. All patients were New York Heart Association class I or II. No death, heart transplantation, or mechanical support initiation occurred during follow-up.

Conclusion: LVAD therapy can induce significant LV reverse remodeling leading to myocardial recovery in a non-negligible proportion of patients, particularly young patients with toxic and non-ischemic cardiomyopathies. Early reverse remodeling with decreasing LVEDD and improving LVEF at 3 months following LVAD implantation is associated with successful subsequent mechanical support weaning. In a subset of patients pump thrombosis appears to be associated with LV reverse remodeling and weaning of mechanical support. Weaned patients maintain partial or complete LVEF recovery after LVAD explantation and have good long-term event-free survival.