Long-term clinical experience with cardiac contractility modulation therapy delivered by the Optimizer Smart system

Abstract

Aims: We assessed long-term effects of cardiac contractility modulation delivered by the Optimizer Smart system on quality of life, left ventricular ejection fraction (LVEF), mortality and heart failure and cardiovascular hospitalizations.

Methods and results: CCM-REG is a prospective registry study including 503 patients from 51 European centres. Effects were evaluated in three terciles of LVEF (≤25%, 26-34% and ≥35%) and in patients with atrial fibrillation (AF) and normal sinus rhythm (NSR). Hospitalization rates were compared using a chi-square test. Changes in functional parameters of New York Heart Association (NYHA) class, Minnesota Living with Heart Failure Questionnaire (MLWHFQ) and LVEF were assessed with Wilcoxon signed-rank test, and event-free survival by Kaplan-Meier analysis. For the entire cohort and each subgroup, NYHA class and MLWHFQ improved at 6, 12, 18 and 24 months (P < 0.0001). At 24 months, NYHA class, MLWHFQ and LVEF showed an average improvement of 0.6 ± 0.7, 10 ± 21 and 5.6 ± 8.4%, respectively (all P < 0.001). LVEF improved in the entire cohort and in the LVEF ≤25% subgroup with AF and NSR. In the overall cohort, heart failure hospitalizations decreased from 0.74 [95% confidence interval (CI) 0.66-0.82] prior to enrolment to 0.25 (95% CI 0.21-0.28) events per patient-year during 2-year follow-up (P < 0.0001). Cardiovascular hospitalizations decreased from 1.04 (95% CI 0.95-1.13) events per patient-year prior to enrolment to 0.39 (95% CI 0.35-0.44) events per patient-year during 2-year follow-up (P < 0.0001). Similar reductions of hospitalization rates were observed in the LVEF, AF and NSR subgroups. Estimated survival was significantly better than predicted by MAGGIC at 1 and 3 years in the entire cohort and in the LVEF 26-34% and ≥35% subgroups.

Conclusions: Cardiac contractility modulation therapy improved functional status, quality of life, LVEF and, compared to patients' prior history, reduced heart failure hospitalization rates. Survival at 1 and 3 years was significantly better than predicted by the MAGGIC risk score.

Keywords: CCM therapy; Heart failure.

© 2021 The Authors. European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.

Figures

Figure 1

Change in effectiveness measures [New York Heart Association (NYHA) class, Minnesota Living with Heart Failure Questionnaire (MLWHFQ) and left ventricular ejection fraction (LVEF)] as a function of the duration of follow‐up in months. The upper set of graphs shows these results for the total cohort, while the middle set of graphs provides the results for the LVEF subgroups. In the bottom set of graphs, the results for subgroups with atrial fibrillation (AF) and normal sinus rhythm (NSR) are shown. Decreases in NYHA class and MLWHFQ depict improvement in these measures. Data show consistent improvements in all effectiveness measures for all groups over the 24 months of follow‐up after Optimizer implant.

Figure 2

Kaplan–Meier survival curves for the total cohort and each LVEF group compared to the predicted survival curves for the MAGGIC heart failure risk score. The proportion surviving is presented for 3 years (1095 days) of follow‐up. Patients at risk at each time interval are shown at the bottom of each graph. P‐values provided in the upper right hand corner of each individual graph demonstrate that observed survival was statistically better than survival predicted by the MAGGIC risk score for the total cohort (A), the LVEF 26–34% group (C) and the LVEF ≥35% group (D). There was no difference between observed and predicted survival in the LVEF ≤25% group (B).

Figure 3

Kaplan–Meier survival curves for each left ventricular ejection fraction (LVEF) tercile in the group of patients with atrial fibrillation. Survival in the atrial fibrillation subgroup was highly dependent on LVEF (P = 0.004).