Redefining response to Cardiac Resynchronisation Therapy: A Post-hoc Analysis of the MORE-CRT MPP trial

Area of Science:

• Cardiology
• Medical Technology
• Clinical Trials

Background:

• Cardiac resynchronization therapy (CRT) response is typically assessed at 6 months using left ventricular end-systolic volume (LVESV) and clinical outcomes.
• Some patients initially classified as non-responders to CRT may show improvement or stabilization by 12 months.

Purpose of the Study:

• To investigate the echocardiographic response trajectories in CRT patients.
• To identify predictors of these response patterns.
• To evaluate the clinical course of patients who stabilized or deteriorated after the initial 6-month assessment.

Main Methods:

• Post-hoc analysis of the MORE-CRT MPP trial involving patients receiving biventricular pacing.
• Classification of patients into early responders (>15% LVESV reduction at 6 months), delayed responders (<15% at 6 months, >15% at 12 months), and non-responders.
• Further categorization of 6-month non-responders into stabilized or deteriorated groups based on 12-month LVESV changes.
• Analysis of heart failure hospitalization (HFH) or death using survival models.

Main Results:

• Event-free survival significantly differed among early, delayed, and non-responders (p<0.001).
• Non-responders had substantially shorter event-free survival compared to both early (52% shorter) and delayed responders (38% shorter).
• Among non-responders, 39.0% stabilized and 61.0% deteriorated, with divergent outcomes after 6 months (p<0.001).
• Ischemic etiology, non-Left Bundle Branch Block (LBBB), and lower baseline ejection fraction predicted delayed response.

Conclusions:

• Delayed CRT responders exhibit clinical outcomes comparable to early responders over the follow-up period.
• These findings advocate for a 12-month assessment interval for CRT response.
• Trajectory-based definitions of CRT response are supported by these results.