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 31 +/- 8 years [mean +/- SD]) with familial hypercholesterolemia (FH) and a matched group of 20 healthy control subjects. Background. Precursors 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 dipyridamole induced hyperemia using positron emission tomography and oxygen-15-labeled water. Results. Serum total and low density lipoprotein cholesterol concentrations sere higher in the patients than in the control 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 in both groups after dipyridamole infusion, but the flow at maximal vasodilation 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 (the 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 = 0.0008), Total coronary resistance during hyperemia was higher in the patients than in the control subjects: 36 +/- 25 versus 21 +/- 10 mm Hg/min per g per mi (p = 0.045). Coronary flow reserve was inversely associated 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