Long-term outcome after upgrade to cardiac resynchronization therapy: A propensity score-matched analysis

Area of Science:

• Cardiology
• Electrophysiology
• Heart Failure Management

Background:

• Cardiac resynchronization therapy (CRT) is a key treatment for heart failure patients with wide QRS complexes.
• Limited data exist on the long-term outcomes specifically for patients upgraded to CRT from other devices.

Purpose of the Study:

• To compare the long-term outcomes of patients undergoing de novo CRT implantation versus those upgraded to CRT.
• To investigate the impact of CRT upgrades on mortality, heart transplantation, ventricular assist device implantation, and heart failure admissions.

Main Methods:

• Retrospective analysis of a multicenter registry including 2275 patients with de novo or upgraded CRT.
• Mean follow-up of 3.6 years; primary endpoint: all-cause mortality, heart transplant, or VAD implantation.
• Secondary endpoint: heart failure admission; analyses included multivariable Cox regression and propensity score matching (PSM).

Main Results:

• Patients upgraded to CRT (n=605) had distinct characteristics, including less female representation, more ischemic cardiomyopathy, and worse renal function.
• The composite endpoint incidence was higher in the CRT upgrade group (10.8%/year) vs. de novo CRT (7.1%/year).
• After PSM, CRT upgrade was associated with increased risk for the composite endpoint (HR 1.35) and heart failure admission (HR 1.74), particularly from ICD.

Conclusions:

• Long-term outcomes after CRT upgrade differ significantly from de novo CRT implantation, especially when upgrading from an implantable cardioverter-defibrillator (ICD).
• Observed outcome differences likely reflect baseline patient population disparities rather than a direct causal effect of the upgrade therapy itself.