Clinical Spectrum and Outcomes in Hypertrophic Cardiomyopathy With Apical Aneurysms: A Large Multicenter...

Apical aneurysms in hypertrophic cardiomyopathy (HCM) have been linked to sudden cardiac death (SCD) and a nidus for thromboembolism. Uncertainty remains regarding the level of risk and significance of aneurysm size.

The objective of the study was to determine the rate of SCD events and prevalence of apical thrombus or embolic events by size (maximum transverse dimension).

Apical aneurysms were identified in 510 patients from 10 centers, followed a median of 4.1 years for SCD events (SCD, appropriate implantable cardioverter defibrillator therapy, and resuscitated SCD) or development of apical thrombus/thromboembolism. Relationship between size and SCD events was analyzed using multivariable Cox proportional hazard models.

In 510 HCM patients: 19% had small aneurysms (<10 mm), 39% medium (10-19 mm), 39% large (20-39 mm), and 3% very large (≥40 mm). SCD event rate was 2.1%/year, with risk increasing with increasing aneurysm size: 0.2%/year in small, 2.3%/year in medium, 3.0%/year in large and 8.2%/year in very large (P < 0.001). On multivariable analysis, greater size was associated with SCD events, independent of other risk markers or European Society of Cardiology-SCD score. Either an embolic event (3.6% of patients) or apical thrombus (10% of patients) occurred in 13% of patients and was independently associated with greater aneurysm size, 3% in small to 25% in very large aneurysms (P < 0.001).

In a large cohort of HCM patients with apical aneurysms, rates of SCD events were high, with continuous relationship between size and risk. Small aneurysms (<10 mm) were associated with low risk for SCD events (0.2%/year), whereas aneurysms ≥10 mm with high risk (>2%/year). Although embolic events were uncommon, increasing aneurysm size was associated with the prevalence of apical thrombi.