Left Ventricular Functional Improvement is Associated With Lower Morbidity and Mortality During Long-Term Mechanical Circulatory Support: An STS Intermacs Analysis.

Background

A subset of patients with advanced heart failure (HF) supported with durable left ventricular assist devices (LVADs) demonstrate significant improvement in left ventricular ejection fraction (LVEF), but the impact of such functional improvement on clinical outcomes is unclear.

Methods

We analyzed adults in the STS-Intermacs registry who underwent continuous-flow LVAD implantation (2006-2017) and had echocardiographic data ≥6 months post-implant. Post-LVAD myocardial function was defined by the maximum LVEF after ≥6 months of support and categorized as <40% vs ≥40% and into finer strata. Outcomes included all-cause mortality, clinically significant sustained cardiac arrhythmia, hepatic and renal dysfunction, CVA/TIA, right HF during follow-up, and HF hospitalization. Incidence rates and incidence rate ratios were calculated during 6-month landmarked follow-up through 5 years, and associations were assessed using landmarked multivariable Cox models.

Results

Among 9,518 eligible patients (age 56.6±13.2 years, 21.4% female), 1,131 (12%) achieved LVEF ≥40% over a median 27.0 months of follow-up. Compared with LVEF <40%, LVEF ≥40% was associated with lower adjusted incidence rates of death (adjusted IRR 0.85, 95% CI 0.73-0.98), arrhythmia (0.59, 0.48-0.72), hepatic dysfunction (0.58, 0.35-0.97), and HF hospitalization (0.65, 0.51-0.82), whereas adjusted differences in right HF and renal dysfunction were not significant. In adjusted time-to-event analyses, LVEF ≥40% was independently associated with lower hazards of all-cause mortality (aHR 0.82, 95% CI 0.71-0.96), HF hospitalization (0.63, 0.50-0.80), cardiac arrhythmia (0.69, 0.58-0.83), and hepatic dysfunction (0.57, 0.37-0.88). Across ordered LVEF strata, higher LVEF was associated with progressively lower risks of death and HF-related events.

Conclusions

In a large multicenter LVAD cohort, LV functional response to durable support spanned a spectrum, with ∼1 in 8 (12%) durable LVAD recipients achieving a maximum post-implant LVEF ≥40% after ≥6 months of support. Higher post-implant LVEF was independently associated with improved survival and fewer HF-related events. These findings support viewing myocardial improvement during LVAD support as a clinically meaningful target that affects positively the outcomes of patients while being on mechanical support.