Clinical outcomes after upgrade to resynchronization therapy: a propensity-score matched comparative analysis

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND Upgrade to resynchronization therapy (CRT) is common practice in Europe. However, guideline recommendations are discordant and randomized trials are lacking. Previous studies have shown worse outcomes in upgraded patients. AIM To compare clinical outcomes in a cohort of patients receiving de novo or upgrade to CRT. METHODS Single-center retrospective study of consecutive patients submitted to CRT implantation (2007-2018). Major adverse cardiac events (MACE) included heart failure hospitalization or all-cause mortality. Clinical response was defined as NYHA class improvement without MACE in the 1st year of follow-up (FU). Left ventricle end-systolic volume reduction of >15% designated echocardiographic (echo) response. Survival analysis with Kaplan-Meier method and Log-rank test was performed. Propensity-score matching (PSM) analysis was performed to adjust for possible confounder variables. RESULTS 295 CRT patients (70.5% male, mean age 67 ± 11 years, 72.5% non-ischemic cardiomyopathy, 54.6% implanted with CRT-D) were included. Fifty-six patients (19%) underwent an upgrade: 43 (78.2%) from a pacemaker and 12 (21.8%) from a defibrillator device. Indications for upgrade were mainly pacemaker dependency or pacing-induced LV dysfunction (76.6%) and de novo left bundle branch block (23.4%). Upgraded patients were older (70 vs 66 years, p=.034), with larger baseline QRS (185 ± 25 vs 163 ± 30 ms, p<.001) and higher rates of atrial fibrillation (58.2% vs 26.7%, p<.001), coronary artery disease (41.8% vs 26.2%, p=.033), moderate to severe valve disease (42.9% vs 22.6%, p=.003) and chronic kidney disease (36.4% vs 18.7%, p=.008). Upgraded patients more frequently received CRT-P (71.4% vs 39.3%, p<.001). CRT-D were more often implanted for secondary prevention (53.3% vs 20.2%, p=.011) in the upgrade group. There were no differences in procedural complications, clinical (59.3 vs 62.6%, p=.765) or echo (72.2% vs 71.9%, p=.970) response rates. During a median FU of 3 ± 5 years, all-cause mortality was similar among groups (Log-rank test, p=.688). MACE occurred more frequently in the upgrade group (Log-rank test, p=.025). No differences emerged in lead complications (8.9% vs 8.4%, p=.892) or device infection (1.8% vs 2.9%, p=.986). PSM analysis identified 106 matched pairs (56 upgrade/50 de novo patients), without baseline statistical differences. All-cause mortality (Log-rank test, p=.555) and MACE (Log-rank test, p=.574) were comparable between groups. CONCLUSION In this cohort, upgrade to CRT was comparable to de novo implantation in terms of clinical and echo response. Moreover, upgrade to CRT was not associated with higher complication rates. All-cause mortality and MACE were similar between groups.