Acute coronary syndrome with non-obstructive coronary arteries (ACS-NOCA) in patients with hypertrophic cardiomyopathy

OBJECTIVES: Our study aimed to determine the prevalence and prognosis of acute coronary syndrome with non-obstructive coronary artery (ACS-NOCA) in patients with hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS: We enrolled a total of 200 consecutive patients with HCM over a 139-month period from 2002 to 2013. The study found that 28 patients (14% of overall patients, 51% of patients with ACS) had ACS-NOCA, and 18 patients (9% of overall patients, 86% of patients with acute MI) had MINOCA as initial clinical presentations. The highest prevalence of non-obstructive coronary artery disease (NOCA) in patients with HCM was found in acute ST-elevation myocardial infarction (STEMI) (100%), followed by non-STEMI (82%), and unstable angina (29%). Patients with ACS-NOCA had more frequent ventricular tachycardia and lower resting left ventricular (LV) outflow tract gradients than those with no ACS-NOCA (p < 0.05 for all). The ACS-NOCA group had a lower probability of HCM-related death compared with the no ACS-NOCA group and the significant coronary artery disease (CAD) group (p-log-rank = 0.0018). CONCLUSIONS: MINOCA or ACS-NOCA is not an uncommon initial presentation (prevalence rate 9–14%) in patients with HCM. NOCA was highly prevalent (51–86%) in patients with HCM presenting with ACS and had a favorable prognosis. Our findings highlight as a reminder that in an era of rapid reperfusion therapy, ACS in patients with HCM is not only a result of obstructive epicardial CAD, but also stems from the complex cellular mechanisms of myocardial necrosis.