Estimated Prevalence of Heterozygous Familial Hypercholesterolemia in Patients With Acute Coronary Syndrome

Heterozygous familial hypercholesterolemia (FH) represents a strong risk for development of premature coronary artery disease (CAD). However, the majority of patients with FH are undiagnosed and the prevalence likely represents an underestimate in most countries. In Japan, the possible contribution of FH to the development of CAD may be higher because of the low incidence of CAD among the general population. We estimated the prevalence of heterozygous FH by measuring Achilles tendon thickness (ATT) in patients with acute coronary syndrome (ACS).A total of 359 patients suffering from ACS were enrolled in this multicenter registration study. Heterozygous FH was defined according to the diagnostic criteria proposed by the Japan Atherosclerosis Society. After excluding 63 patients because of missing ATT data or plasma triglyceride levels that were 4.5 mmol/L or more, 296 patients were eligible for inclusion in the study. The number of patients with ATT of 9 mm or more was 53 (17.9%). They were significantly younger and had significantly higher LDL cholesterol levels than patients with an ATT less than 9 mm. The prevalence of heterozygous FH was 5.7% (1/17.5) and more prominent in younger patients who were less than 60 years old (7.8%). In patients with ATT of 9 mm or more, approximately 1 in 3.5 fulfilled the criteria for heterozygous FH.We demonstrated the usefulness of measuring ATT by radiography and the high prevalence of heterozygous FH in patients with ACS in Japan, especially in younger patients who were less than 60 years old.