Stroke and Embolic Events in Hypertrophic Cardiomyopathy
What is the risk of embolic events in hypertrophic cardiomyopathy (HCM), and what are the risk factors for those without documented atrial fibrillation (AF)?
The study cohort was comprised of 593 patients with clinically diagnosed HCM (age at diagnosis, 51.0 ± 15.6 years). The authors used Kaplan-Meier method to estimate embolic event-free curves and the log-rank test to assess the differences between these curves. Multivariate and univariate Cox proportional hazard models were used to evaluate the impact of various risk markers on stroke and systemic embolic events. Multivariate models included age, gender, the presence of known risk markers related to HCM (family history of sudden death, unexplained syncope, left ventricular [LV] intracavitary gradient, max LV wall thickness ≥30 mm, nonsustained ventricular tachycardia, and left atrial dimension ≥48 mm).
The investigators found that 11.5% of the cohort (n = 68) experienced stroke and systemic embolic events during the mean follow-up period of 10 ± 7.5 years). The mean age at the event was 60.4 ± 11.5 years (range, 23-83 years). Ischemic stroke occurred in 91.2% (62 out of 68 patients) including four patients with intracerebral hemorrhage; 8.8% (6 out of 68) had embolic events to other organs including the brain: kidney (n = 4), upper limb (n = 1), and lower limb (n = 1). AF was documented in 42.6% (29 out of 68 patients) before the event. In 7.4% (n = 5) of the patients, AF was documented for the first time of the event, and in 14.7% (n = 10), it was detected after the event. In patients without previously documented AF (39 with events and 392 events), independent determinants of embolic events after adjusting for gender and classic prognostic markers include older age at diagnosis and left atrial dimension ≥48 mm.
The authors concluded that the incidence of stroke and systemic embolic events was about 1.0% every year, and that these patients had a higher prevalence of AF than those without an event. In patients without previously documented AF, older age at diagnosis and enlarged left atrium were independent determinants of stroke.
This is an important study because it reiterates the findings of earlier studies that stroke and embolic events in HCM patients are related to AF. Further studies are needed to determine whether older patients or those with enlarged left atria in those without AF will benefit from prophylactic anticoagulation.
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