P184 - WHAT IS THE MEANING OF MAXIMALLY TOLERATED GUIDELINE-DIRECTED MEDICAL THERAPY IN PATIENTS WITH LEFT VENTRICULAR ASSIST DEVICES? INSIGHTS FROM A CANADIAN TERTIARY CENTRE

Background: In rare patients with left ventricular assist devices (LVADs), implantation may reduce stress on the left ventricle (LV) and allow for reverse remodeling leading to weaning. There is a paucity of data regarding the use of heart failure therapies in patients with LVADs. While the use of guideline-directed medical therapy (GDMT) post-LVAD implant has largely focused on blood pressure management in practice, current evidence suggests its use may increase device explantation rates and functional capacity.

METHODS AND RESULTS: We retrospectively reviewed all 98 patients who underwent implantation of second- or third-generation LVAD (HeartMate2 n=76, HeartMate3 n=17, HeartWare n=5) at our tertiary centre between 2009-2021. Pump speed was set to maximize unloading of the LV. While patients were supported by the LVAD, maximally tolerated GDMT was initiated. Fourteen patients underwent LVAD weaning after mean support time of 323 days. Among unweaned patients, 9 had unavailable data. Within one year of implantation, 7 had underwent heart transplantation (among which 4 died of transplant complications) and 7 had died while on LVAD support (from LVAD hemorrhagic complications or worsening cardiogenic shock following implantation). For the remaining unweaned patients (n=61), adherence to and doses of GDMT components were assessed between 6-18 months (mean 362±67 days) following implantation. Weaned patients were evaluated within 3 months of explanation.

Significantly more patients in the weaned group had an ACEI/ARB/ARNI [13/14 (93%) vs. 32/61 (52%), p=0.005] and Ivabradine [1/14 (7%) vs. 0/61 (0%), p=0.04], but less had furosemide (1/14 (7%) vs. 24/61 (39%), p=0.02). A numerically higher but non statistically significant proportion of patients in the weaned group had a BB [12/14 (86%) vs. 40/61 (66%), p=0.14]. The groups did not differ with respect to prescription of MRA [1/14 (7%) vs 13/61 (21%), p=0.22) and SGLT2i [0/14 (0%) vs 1/61 (2%), p=0.6312].

Conclusion: Within one year following LVAD implantation, our preliminary data suggests patients who were ultimately weaned from support tolerated a greater number of GDMT agents compared to those who remained on LVAD therapy, as a significantly higher number of weaned patients were prescribed an ACEI/ARB/ARNI while the other classes were similar between both groups. Although the retrospective design of this study precludes conclusions about causality, these findings suggest that tolerance to GDMT may serve as a potential indicator to identify weaning candidates. Nevertheless, overall tolerance to GDMT among patients with LVADs appears to be lower than that observed in patients with heart failure who are not receiving LVAD support.