Impaired Hyperaemic and Rhythmic Vasomotor Response in Type 1 Diabetes Mellitus Patients: A Predictor of Early Peripheral Vascular Disease

Abstract

The smooth muscle of distal vascular networks exhibits periodical contraction and relaxation known as rhythmical vasomotion. The nature of microvascular vasomotion has been shown to correlate with severity of peripheral vascular disease. We present basal and post-ischaemic hyperaemic laser doppler flowmetry vasomotion in control and type 1 adult diabetic patients. Prospective case control study. Laser Doppler flowmetry was used to measure vasomotion and hyperaemic responses in age and body mass index matched male subjects (25 type 1 Diabetes Mellitus and 13 controls), all with ankle/brachial pressure index (ABPI) >1.0 but <1.2. The frequency of resting vasomotion was raised in diabetics compared to controls 8 (5-9)min(-1) vs. 5 (4-6)min(-1) (median (range); p<0.0001). The post ischaemic hyperaemia response was significantly higher in the diabetic group compared to the controls 11 (7-12)min(-1) vs. 6 (5-7)min(-1) (median (range); p<0.05). Post ischaemic hyperaemic flux (expressed as percent increase from resting) was significantly lower in the diabetic group compared to controls (234+/-62 vs. 453+/-155%, p<0.01). The time to achieve peak post ischaemic response was also significantly increased in the diabetic group compared to control: 21.4+/-0.4 vs. 12.8+/-5.4sec (mean+/-SD, p<0.05). Vasomotion frequency and its change during hyperaemic insult is significantly different in Type 1 Diabetes Mellitus subjects compared to controls. The results are similar to patients with macrovascular atherosclerosis. Long term studies of these groups of patients will be required to determine the significance of these findings and whether these changes could be used as a non invasive screening test to predict peripheral early vascular disease in type 1 diabetic patients.