Long-Term Outcomes of Patients With Apical Hypertrophic Cardiomyopathy Utilizing a New Risk Score.

Background: Apical hypertrophic cardiomyopathy (aHCM) is a distinct variant characterized by predominant hypertrophy of the left ventricle apex.

Objectives: This study sought to describe aHCM patients' characteristics and develop a risk score for aHCM patients.

Methods: A total of 462 patients (age 58 ± 15 years, 68% male) diagnosed with aHCM were included. The primary endpoint was death, appropriate defibrillator discharge, or need for cardiac transplantation. Variables showing potential association with the composite endpoint were considered to develop an aHCM-specific risk score.

Results: At baseline, 67% patients were asymptomatic and 69% had no risk factors for sudden death. On echocardiography, the mean left ventricle ejection fraction, left atrial volume index, and right ventricular systolic pressure were 64% ± 8%, 36 ± 15 ml/m, and 32 ± 10 mm Hg, respectively, with 51(11%) demonstrating an apical aneurysm. Baseline cardiac magnetic resonance, performed in 246 (53%) patients, demonstrated delayed gadolinium enhancement in 170 (71%) patients (mean percentage of 4.9% ± 6.6%). At age 6.3 ± 4.8 years, the composite events occurred in 80 (17%, death in 62 [13%]) patients. The aHCM-specific risk score, incorporating age, apical aneurysm, left atrial volume index, serum creatinine, and right ventricular systolic pressure, demonstrated good discrimination (C-statistic = 0.75) with an expected to observed ratio of 1.02 and a calibration slope of 0.91. The risk score ranged between 0 and 8 points, with a higher score associated with higher composite events.

Conclusions: aHCM constituted 6.8% of our overall HCM cohort with a composite event rate of 2.8%/year. The aHCM risk score provided good discrimination in predicting the composite primary endpoint, with a higher score associated with a higher rate of events.