Functional and Structural Myocardial Improvement after LVAD Therapy: The U-NOVA Reverse Remodeling Stages

Abstract

Background The degree of left ventricular morphological and functional improvement following continuous flow left ventricular assist device (LVAD) implantation is variable. Objectives To evaluate the continuum of left ventricular reverse remodeling after LVAD implantation by serial echocardiographic imaging in an effort to define stages of reverse remodeling. Methods Consecutive patients with heart failure who required mechanical circulatory support with a durable LVAD were enrolled from two programs (UTAH consortium and Inova). Echocardiograms were performed within 1-month preceding LVAD implantation and then 1,2, 3, 6, 9, and 12 months after. Patients were categorized by the degree of morphologic and functional change after LVAD support. Results The study included 358 patients with baseline and at least 6-month follow up measurements. The mean duration of heart failure was 6.9 ± 6.7 years, baseline left ventricular ejection fraction (LVEF) was 19 ± 7%, with mean left ventricular end-diastolic internal dimension (LVIDd) 6.8 ± 1.0 cm. In the cohort, 34 patients (10%) experienced improvement of the LVEF ≥ 40% and LVIDd ≤ 6.0cm and were termed as responders. The remaining patients were categorized as non-responders, borderline responders and partial responders by an increase in LVEF during follow-up (∆) LVEF 10%, respectively. Most patients were non-responders (n=212, 59%), followed by borderline responders (n=55, 15%) and partial responders (n=57, 16%). Multivariable logistic regression identified smaller initial LVIDd (OR 1.77 per 1 cm decrease, 95% CI 1.15-2.3, p=0.009), use of an axial flow device (OR 2.57, 95% CI 1.08-6.12, p=0.033), and shorter heart failure duration (OR 1.10 per 1-year decrease, 95% CI 1.01-1.20, p=0.047) as predictors of response. Conclusions Reverse left ventricular remodeling associated with durable LVAD support is not an all or none phenomenon and as many other biological phenomena manifests as a continuous spectrum. Defining 4 stages across this continuum may have clinical management implications and may also facilitate advancing the field of myocardial plasticity by informing the study design of future investigations.