IMPAIRED PERIPHERAL VASOMOTION IN DIABETES

OBJECTIVE - To test the hypothesis that vasomotion, the rhythmic contr action exhibited by small arteries and arterioles, is impaired in diab etic subjects compared with healthy control subjects. RESEARCH DESIGN AND METHODS - We mathematically modeled the oscillations in laser Dopp ler microvascular measurements taken from the pulpar surface of the in dex finger in 20 healthy control subjects and 20 age-matched diabetic subjects (8 with type I and 12 with type II diabetes). The mean durati on of diabetes was 17.1 +/- 2.3 years, and mean HbA(1c) was 9.1 +/- 0. 4%. Blood flow was measured for 5 min as subjects rested quietly in a closed room. Fast Fourier transformation was performed to provide the frequency power spectrum of each recording. Amplitude of vasomotion wa s correlated with six quantitative measurements of neuropathy. neuropa thy. RESULTS - Diabetic subjects had impaired low-frequency oscillatio n vasomotion in 75% of age-marched patients (15 of 20 patients), with mean amplitudes of 24.9 +/- 6.4 vs. 129.0 +/- 33.2 (P < 0.0039). Of si x somatic and autonomic neuropathy variables, only the warm thermal se nsory threshold correlated significantly with the mean amplitude of va somotion (r = -0.75, P < 0.0009). CONCLUSIONS - Patterns of peripheral vasomotion are clearly disordered in diabetes. The loss of low-freque ncy oscillations observed here suggests a peripheral vascular abnormal ity that extends past the capillary network to arterial vessels. It is uncertain whether the accompanying small unmyelinated nerve C-fiber d ysfunction is a cause or consequence of the impaired microvascular fun ction. Measurement of vasomotion may prove useful as a novel test for peripheral neurovascular function.