SYMPATHETIC FUNCTION-TEST OF VASOCONSTRICTOR CHANGES IN FOOT ARTERIESIN DIABETIC-PATIENTS

OBJECTIVE - We studied the relationship between vasoconstrictor change s in foot arteries (pedal, metatarsal, and digital arteries) and auton omic neuropathy in diabetic patients to estimate the degrees of sympat hetic dysfunction. RESEARCH DESIGN AND METHODS - Sixty-two patients an d nineteen age-matched control subjects were studied. The resistance i ndex (RI) and pulsatility index (PI) were measured as vascular hemodyn amic parameters using Doppler sonography, and the increases in these h emodynamic parameters (%RI and %PI) from rest to a deep breath were me asured as indexes of the degrees of sympathetic vasoconstrictor functi on. Cardiovascular autonomic function tests (AFTs) were performed and the score was compared to %RI and %PI values obtained. RESULTS - Of th e 62 diabetic patients, 51 had various degrees of autonomic neuropathy . Both %RI and %PI in the diabetic patients were significantly less th an those in the control subjects for all foot arteries tested (all P < 0.001). There were strongly inverse correlations between the %RI and %PI of foot arteries and the AFT score (r = -0.556 to -0.846, P < 0.00 01). The %RI of the digital artery was the most strongly correlated wi th AFT score (r = -0.846, P < 0.0001) among foot arteries tested. The abnormality of sympathetic vasoconstriction was detectable in the majo rity of the diabetic patients with the early phase of autonomic neurop athy (%RI: 89.5%; %PI: 94.5%). CONCLUSIONS - We conclude that the %RI of the digital artery is a useful and reliable sympathetic function te st of early phase in diabetic patients.