抄録
To clarify whether vascular dysfunction is present in patients with non-insulin-dependent diabetes mellitus (NIDDM) without clinical evidence of peripheral vascular disease (PVD), both pulsatility index (PI; indicating a determinant of arterial distensibility) determined by high-resolution ultrasonography and ankle pressure index (API) after leg exercise and sublingual nitroglycerin (NTG; causing endothelium-independent vasodilatation) were measured in ankle vessels of 63 patients with NIDDM and 37 age- and gender-matched healthy control subjects. The diabetic patients were subdivided into two groups according to the PI value at the baseline; Group A (PI≥6.52, n=31) and Group B (PI<6.52, n=32). There were no significant differences between Group A and B in age, gender, known duration and treatment of diabetes, and the frequency of smoking, hypertension and diabetic retinopathy. However, the frequency of albuminuria was higher in Group B. There were no differences found in the responses of PI and API to leg exercise within the groups, whereas both indices increased significantly (p<0.05) in the control group after exercise. Vascular responses to sublingual NTG load were analyzed in 22 of 63 patients (Group A: n=10, B: n=12) and 31 of 37 control subjects. No differences were noted in any other clinical characteristics among the groups, except that the mean HbA1c and triglyceride (TG) levels were significantly (p<0.05) higher in Group B than in Group A. Both the PI and API were significantly (p<0.05-0.01) decreased in Group B after loading, whereas those in control subjects and Group A remained unchanged after loading. In addition, a direct correlation was found between changes (Δ) in PI and basal TG levels in Group B. These results suggest that in patients with NIDDM uncomplicated by overt PVD, the PI may be an indicator that enables objective assessment of vascular dysfunction at an early stage of atherosclerosis, and that vasodilation in response to sublingual NTG, a smooth muscle-dependent vasodilation, may be blunted in diabetic patients with occult PVD as evidenced by decreased PI values in our series.
