Mavacamten in Obstructive Hypertrophic Cardiomyopathy: National Insights on Access and Safety Profile From Real-World...

Mavacamten improves symptoms in obstructive hypertrophic cardiomyopathy, but real-world prescription patterns, safety profile, and the effect of atrial fibrillation (AF) on outcomes remain unclear.

An observational multicenter analysis using patient-level data from the TriNetX database (2011-2023) compared patients with obstructive hypertrophic cardiomyopathy treated with mavacamten versus those not treated with mavacamten (controls). Multivariable logistic regression identified predictors of mavacamten use. Propensity-score matching was used to reduce confounding bias. Outcomes included acute heart failure, left ventricular systolic dysfunction, cardiovascular hospitalization, new-onset AF, and all-cause mortality. Outcomes were also stratified by AF history.

Among 15 145 patients, 509 (3.5%) received mavacamten; 502 matched to 1475 weighted 1:3 controls (equivalent to 502). Black patients were significantly less likely to receive mavacamten compared with White patients (odds ratio, 0.45 [95% CI, 0.33-0.63]). Of the 502 mavacamten recipients, 4.8% experienced acute heart failure, 8.3% experienced systolic dysfunction, 10.8% experienced cardiovascular hospitalization, 6.4% experienced new-onset AF, and 1.4% died. Overall outcomes were similar between both groups except for a higher incidence of systolic dysfunction in mavacamten patients (log-rank P<0.001). Among mavacamten patients, those with baseline AF (28%) had significantly higher rates of acute heart failure (7.8% versus 3.6%; P=0.047), systolic dysfunction (12.8% versus 6.4%; P=0.02), cardiovascular hospitalization (27.7% versus 4.2%; P<0.01), and mortality (5% versus 0%; P<0.01). Older age independently predicted acute heart failure, whereas baseline AF predicted both cardiovascular and all-cause hospitalization.

Black patients have markedly lower access to mavacamten. Preexisting AF was associated with a higher risk of adverse outcomes for patients on mavacamten, highlighting the need for careful monitoring.