Re-Evaluation of Response to Cardiac Resynchronization Therapy: Long-Term Impact of Echocardiographic Non-Progression

Background: The concept that significant left ventricular (LV) reverse remodelling is needed to define “responders” to cardiac resynchronisation therapy (CRT) has been increasingly questioned. Since heart failure (HF) is a progressive disease, patients with minimal changes in LV geometry, recently defined as “Non-Progressors”, may also derive some benefit from CRT. The main purpose of this study was to evaluate long-term prognosis according to LV end-systolic volume (LVESV) change after CRT. Methods and Results: We included 207 consecutive patients submitted to CRT, divided into 3 groups based on LVESV variation at 6-month follow-up: “Responders” (R): ≥15% LVESV reduction; “Non-Progressors” (NPr): 0-15% and “Progressors” (Pr): increase in LVESV. During a follow-up of 54.2±33.1 months, all-cause and cardiovascular mortality, HF hospitalisations, functional class and cardiac transplantation need were evaluated. Independent predictors of HF progression were also assessed. At 6-month after CRT, there were 117 (56.5%) R, 32 (15.5%) NPr, and 58 (28.0%) Pr. NPr demonstrated a non-significant improvement of all predefined outcomes compared to the Pr. Nevertheless, the hazard ratio for time-to-event risk analysis of all-cause mortality and HF hospitalisations, showed R to have a two-fold lower risk compared to the Pr and, to a lesser extent yet still approximated, to the NPr. Ischemic cardiomyopathy, chronic kidney disease and NYHA class IV at baseline were identified as independent predictors of HF progression. Conclusion: Non-Progressors demonstrated better outcomes than Progressors. However, regarding survival and HF hospitalisations, positive reverse remodelling, and not only stabilisation, seems to confer better long-term prognosis with fewer time-to-event risks associated.