Abstract Body (Do not enter title and authors here): Left ventricular assist devices (LVAD) are increasingly used in refractory heart failure, mainly as a bridge to transplant or as destination therapy. LVAD unloading of the left ventricle (LV) can also promote myocardial recovery leading to improvement of the LV systolic function, allowing LVAD explantation. However, parameters associated with LVAD weaning and long-term outcomes 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.

We conducted a single-center retrospective study recruiting 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 LVAD implantation during this period. All patients were on guideline-directed medical therapy (GDMT). Fourteen patients (14%) had significant LV recovery and were explanted/decommissioned after a median support time of 309 days (range 55-595 days). Toxic cardiomyopathy, defined as abuse of amphetamines (n=2), energy drinks (n=2) or multiple substances (n=6), was the most likely diagnosis in 10 of the weaned patients (71%). The LVEF was significantly higher and the left ventricular end-diastolic diameter (LVEDD) was significantly lower in weaned patients compared to unweaned patients after 3 months of support. Myocardial recovery manifested as pump thrombosis in 4 of the weaned patients (29%). Prior to explantation, 12 patients had a decrease in GDMT doses to minimize post explantation vasoplegia. After explantation, median follow-up time was 40 months (range 8-109 months) and the majority of patients were anticoagulated for 3 months. At last follow up, the LVEF was 44±6% and no patient had a LVEF below 35%. All patients were NYHA I or II and no death, heart transplant, or mechanical support initiation occurred.

LVAD therapy can induce LV reverse remodeling leading to myocardial recovery in a significant proportion of patients, especially young patients with toxic and non-ischemic cardiomyopathies. Early reverse remodeling with decreasing LVEDD and improving LVEF at 3 months following implantation is associated with successful weaning. Pump thrombosis seems to be associated with LV reverse remodeling and weaning of mechanical support in certain patients. Weaned patients maintain satisfactory LVEF recovery after explantation and have good long-term event-free survival.