CORONARY FLOW RESERVE IS IMPAIRED IN YOUNG MEN WITH FAMILIAL HYPERCHOLESTEROLEMIA

Objectives. We sought to investigate whether functional abnormalities in coronary vasomotion exist in young adults by studying 15 men (age 3 1 +/- 8 years [mean +/- SD]) with familial hypercholesterolemia (FH) a nd a matched group of 20 healthy control subjects. Background. Precurs ors of morphologic coronary artery disease are known to be present in adolescents and young adults with a high risk factor profile, Methods. Myocardial blood flow was measured at the basal state and during dipy ridamole induced hyperemia using positron emission tomography and oxyg en-15-labeled water. Results. Serum total and low density lipoprotein cholesterol concentrations sere higher in the patients than in the con trol subjects (mean +/- SD): 7.7 +/- 1.9 versus 5.3 +/- 1.5 mmol/liter (298 +/- 73 vs. 205 +/- 58 mg/dl) and 6.1 +/- 1.8 versus 3.5 +/- 1.4 mmol/liter (236 +/- 70 vs. 135 +/- 54 mg/dl), respectively (both p < 0 .001), The baseline myocardial blood flow was similar in the patients and control subjects: 0.92 +/- 0.24 versus 0.83 +/- 0.13 ml/g per min, respectively (p = 0,21), A significant increase in how was observed i n both groups after dipyridamole infusion, but the flow at maximal vas odilation was 29% lower in the patients: 3.19 +/- 1.59 versus 4.49 +/- 1.27 ml/g per min (p = 0.011), Consequently, coronary flow reserve (t he ratio of hyperemia Bow to basal flow) was 35% lower in the patients than in the control subjects: 3.5 +/- 1.6 versus 5.4 +/- 1.5 (p = 0.0 008), Total coronary resistance during hyperemia was higher in the pat ients than in the control subjects: 36 +/- 25 versus 21 +/- 10 mm Hg/m in per g per mi (p = 0.045). Coronary flow reserve was inversely assoc iated with serum total cholesterol concentration: r = -0,43 (p = 0.009 ), Conclusions. Coronary flow reserve is reduced in young men with FH, and, consequently, coronary resistance during hyperemia is increased, The results demonstrate very early impairment of coronary vasomotion in hypercholesterolemic patients. (C) 1996 by the American College of Cardiology