Population-Level Impact of the Guidelines Update on Patient Selection and Outcomes After Cardiac Resynchronization Therapy

This study sought to analyze the impact of the American College of Cardiology, American Heart Association, and Heart Rhythm Society (ACC/AHA/HRS) guidelines for cardiac resynchronization therapy with defibrillator (CRT-D) update on utilization and efficacy of CRT-D.In September 2012, the ACC/AHA/HRS guidelines for CRT-D were modified to include left bundle branch block (LBBB) as a Class I indication.The IBM Watson MarketScan Database was queried between January 1, 2003, and December 31, 2018, for CRT-D implants or upgrades. The primary outcome was heart failure (HF) hospitalization following left ventricular lead implant. Secondary outcomes included all-cause mortality and device-related lead revision.A total of 27,238 patients were analyzed: 18,384 pre-update and 8,854 post-update. Mean age was 69 ± 11 years, 73% men, and 98% with history of HF hospitalization. The proportion of patients with LBBB increased from 29% to 55% (P < 0.001) after the update. Patients receiving CRT-D post-update demonstrated a greater prevalence of comorbidities, including atrial fibrillation (47% vs 40%; P < 0.001), diabetes mellitus (45% vs 39%; P < 0.001), chronic kidney disease (24% vs 15%; P < 0.001), and HF hospitalization in the year before CRT-D (40% vs 37%; P < 0.001). Despite greater baseline comorbidities, HF hospitalization significantly declined post-update (HR: 0.89; P < 0.001). Multivariate predictors of reduced HF hospitalization included angiotensin receptor neprilysin inhibitor prescription (HR: 0.48; P < 0.001) and presence of LBBB (HR: 0.71; P < 0.001). All-cause mortality was not significantly different between the 2 groups, and fewer lead revisions were noted post-update (0.6% vs 1.7%; P < 0.001).The revised 2012 guidelines led to an increased proportion of LBBB patients receiving CRT-D at the population-level. This change was associated with reduced HF hospitalization, despite broadening therapy to patients with more comorbid conditions.