Coronary flow reserve is reduced in young men with IDDM

Disturbances of coronary circulation have been reported in diabetic patients with microvascular complications hut without obstructive coronary atherosclerosis. The aim of the present study was to investigate coronary flow reserve in young adult patients with IDDM but without microalbuminuria and diabetic autonomic neuropathy. Coronary flow reserve was determined in 12 nonsmoking male patients with IDDM (age 30.0 +/- 6.6 years) and 12 healthy matched volunteers, Groups were similar with respect to blood pressure and serum lipid concentrations, and no subject had a positive family history of coronary heart disease. The patients with IDDM had normal exercise echocardiography and autonomic nervous function tests, Five patients had minimal background retinopathy, and none had microalbuminuria. Positron emission tomography and [O-15]H(2)0 were used to measure myocardial blood Plow at rest and after dipyridamole administration, The studies were performed during euglycemic hyperinsulinemia (serum insulin similar to 70 mU/l),The baseline myocardial blood flow was similar in patients with IDDM and in control subjects (0.84 +/- 0.18 vs, 0.88 +/- 0.25 ml . g(-1). min(-1), NS). The myocardial blood flow during hyperemia was 29% lower in patients with IDDM (3.17 +/- 1.57) compared with the control subjects (4.45 +/- 1.37 ml . g(-1). min(-1), P < 0.05). Consequently, coronary now reserve (the ratio of flow during hyperemia and at rest) was lower in diabetic patients than in control subjects (3.76 +/- 1.69 vs. 5.31 +/- 1.86, P < 0.05) and the total coronary resistance during hyperemia was higher in diabetic patients (53.7 +/- 31.5) compared with the control subjects (31.4 +/- 11.6 mmHg . min . g . ml(-1), P < 0.05), The coronary flow reserve was similar in diabetic patients with and without mild background retinopathy No association was found between the coronary flow reserve and serum lipid or HbA(1c) values in either group, Coronary flow reserve is impaired in yelling adult males with IDDM and no or minimal microvascular complications and without any evidence of coronary heart disease, This abnormality cannot be! explained by standard coronary heart disease risk factors, The results imply early impairment of coronary vascular reactivity in IDDM patients, which may represent an early precursor of future coronary heart disease or may contribute to the pathogenesis of diabetic cardiomyopathy.