Coronary vasoreactivity is not altered in young people with type 1 diabetes

Abnormal coronary microvascular circulation has been demonstrated in diabetes and is associated with increased rate of cardiovascular events. Our objective was to evaluate coronary vasoreactivity in young people with type 1 diabetes with and without microvascular complications.

Twenty-five type 1 diabetic patients without microvascular complications (DC-), 23 with microvascular complications (DC+), and 18 control subjects (C) were studied. Coronary vasoreactivity was assessed by means of coronary flow reserve (CFR). Blood flow velocity in the left anterior descending coronary artery was measured at rest and after high-dose dipyridamole using transthoracic color-guided pulsed Doppler echocardiography. CFR was defined as the ratio of hyperaemic to resting diastolic peak flow velocities. The three groups had similar cardiac function parameters, and also systolic and diastolic blood pressure at rest, which remained unchanged during dipyridamole infusion. Resting coronary flow velocity was comparable in C, DC-, and DC+ (p=ns). Dipyridamole infusion produced a threefold increase in coronary diastolic peak velocity, which reached similar values in C (0.69±0.16 m/s), DC- (0.69±0.18 m/s), and DC+ (0.66±0.11 m/s). Mean CFR ratio was similar in C (3.33±0.66), DC- (3.30±0.51), and DC+ (3.24±0.60). At multiple linear regression analysis, no association was found between CFR and age, sex, HbA(1c), duration of diabetes, and complications.

Coronary vasodilatory function is preserved in young D patients, even those with early microvascular complications, suggesting that coronary vasoreactivity deteriorates at more advanced stages of microvascular complications and/or in the presence of other cardiovascular risk factors.