Coronary ﬂow reserve in angiographically normal coronary arteries with one-vessel coronary artery disease without traditional risk factors

Aims Reduced coronary ﬂow reserve has been reported in patients with traditional risk factors, in particular hyperlipidaemia, despite angiographically normal coronary arteries. However, it is recognized that traditional risk factors do not explain the presence of coronary atherosclerosis in a large proportion of patients. The aim of this study was to assess whether coronary ﬂow reserve is preserved in the myocardium supplied by normal coronary arteries in patients with one-vessel coronary artery disease without traditional risk factors. Methods and Results Positron emission tomography using [ 13 N]ammonia was performed at baseline and after intravenous dipyridamole administration (0·56 mg . dl (cid:1) 1 over 4 min) in 30 subjects: six patients with ischaemia on e ﬀ ort, no myocardial infarction, and isolated left anterior descending coronary artery stenosis without traditional risk factors (coronary artery disease patients without risk factors, aged 59 (cid:2) 13), ﬁve patients with ischaemia on e ﬀ ort, no myocardial infarction, and isolated left anterior descending coronary artery stenosis with multiple risk factors (coronary artery disease patients with risk factors, aged 69 (cid:2) 7), 11 age-matched controls (aged 58 (cid:2) 6), and eight healthy young volunteers (aged 34 (cid:2) 4). Myocardial blood ﬂow calculated in the myocardium supplied by normal coronary arteries in the coronary artery disease patients was compared with those of the two control groups. Coronary ﬂow reserve was deﬁned as the ratio of hyperaemic blood ﬂow after dipyridamole infusion to baseline blood ﬂow. Although coronary ﬂow reserve in the coronary artery disease patients with risk factors was signiﬁcantly lower than that in the age-matched controls (1·62 (cid:2) 0·37, 2·58 (cid:2) 0·71, P =0·0428), coronary ﬂow reserve in the coronary artery disease patients without risk factors was similar to that in the age-matched controls (2·54 (cid:2) 0·17 vs 2·58 (cid:2) 0·71, P =ns). Conclusion Coronary ﬂow reserve is preserved in regions supplied by angiographically normal coronary arteries with one-vessel coronary artery disease without traditional risk factors. (Eur , healthy young volunteers were eight men with a mean age of 34 (cid:2) 4 years (ranging from 30 to 40 years). None of the control subjects had a clinical history or evidence of coronary artery disease or other cardiac disease, hyperlipidaemia, hypertension, diabetes or current smoking. None of the subjects was on continuous medi-cation. Six of the age-matched controls had atypical chest pain, and were referred for coronary arteriography to exclude any organic cause of their symptoms. They had normal coronary arteriograms and left ventriculo-grams, and a negative exercise test. All the participants refrained from consuming ca ﬀ eine-containing food or beverages for (cid:1) 24 h before the study, and patients with coronary artery disease refrained from taking any medi-cation for (cid:1) 12 h before the study. Venous blood samples were taken after a 12 h overnight fast on the same day as the positron emission tomography pro-cedure. Serum total cholesterol, high density lipoprotein (HDL) cholesterol and triglyceride concentrations were measured using standard enzymatic methods. Low density lipoprotein (LDL) cholesterol was calculated using the Friedewald formula [12] .