Survival and Complication Rate After an Upgrade of Pacing System to a Cardiac Resynchronization Therapy Compared to the Implantation of Cardiac Resynchronization Therapy De Novo

Upgrading to cardiac resynchronization therapy (CRT) is an established therapeutic approach for patients with a previously implanted pacemaker or implantable cardioverter-defibrillator (ICD) who subsequently develop symptomatic heart failure with reduced ejection fraction (HFrEF) due to ventricular dyssynchrony. However, the limited number of randomized controlled trials (RCTs) and the inconsistent findings from observational studies underscore the need for large-scale data analyses to guide routine clinical practice. This retrospective, large-cohort study aimed to evaluate survival outcomes and complication rates associated with CRT upgrades, in comparison to de novo CRT implantations. A total of 951 patients were analyzed between 2013 and 2022. The primary predefined endpoints included a comparison of survival, peri-procedural, and early post-procedural complication rates. A secondary endpoint involved the comparison of procedural parameters. Over a 10-year follow-up, Kaplan–Meier curves showed significantly worse survival in the upgrade group compared with the de novo CRT group (p < 0.001). Overall, 313 (40%) de novo and 60 (36%) upgrade patients died. However, in univariable and multivariable analysis, the upgrade procedure itself was not independently associated with all‑cause mortality after adjustment for age, NYHA class, chronic kidney disease, supraventricular arrhythmia episodes, QRS duration, ischemic aetiology and secondary prevention indication (HR 1.18, 95% CI 0.90–1.56, p = 0.23; adjusted HR 1.05, 95% CI 0.65–1.72, p = 0.83). Older age (adjusted HR per year 1.04, 95% CI 1.02–1.05, p < 0.001), NYHA class III,IV (adjusted HR per class 1.39, 95% CI 1.03–1.87, p = 0.034) and ischemic aetiology (adjusted HR 1.40, 95% CI 1.07–1.84, p = 0.013) remained independent predictors of mortality. The overall complication rates were comparable between the two groups. From device or lead related complications, access vein stenosis/thrombosis was more frequent in the upgrade group compared to de novo patients (p < 0.001). From procedural parameters, procedure time was longer in the upgrade patients (p = 0.002). In our retrospective analysis, patients who underwent upgrade to a CRT had a less favorable survival rate according to Kaplan–Meier curves. In both univariable and multivariable analyses, upgrade versus de novo CRT showed no statistically significant effect on mortality. Older age, higher NYHA class and ischemic cardiomyopathy remained independent predictors of mortality. Complication rates were comparable between the de novo and upgrade groups.