Background: Higher arterial stiffness and greater peripheral vascular resistance reduce blood flow in lower-leg arteries and contribute to the development of ischaemic limb in diabetic patients even without peripheral artery occlusive disease. The aim of this study was to clarify whether these vascular parameters are associated with long-term hyperglycaemia in diabetic patients.
Methods: We examined 45 type 2 diabetic patients and 38 age-matched nondiabetic subjects without peripheral artery occlusive disease assessed by ankle-brachial index consecutively admitted to our hospital, and followed them over a 3-year period (3.7 +/- 0.7 years) with no vasodilative medication. Blood flow and resistive index, a measure of peripheral vascular resistance, at the popliteal artery were evaluated using gated two-dimensional cine-mode phase-contrast magnetic resonance imaging. Brachial-ankle pulse wave velocity was measured to assess arterial stiffness.
Results: At baseline, consistent with our previous report, diabetic patients showed higher brachial-ankle pulse wave velocity (p < 0.0001) and resistive index (p < 0.0001) and lower flow volume (p = 0.0044) than those of nondiabetic subjects. Stepwise multiple regression analysis revealed that duration of diabetes, mean HbA(1c) during the study, use of renin-angiotensin system inhibitors and change per year in resistive index were identified as significant independent variables predicting change per year in blood flow (r(2) = 0.733, p < 0.0001) in diabetic patients. Mean HbA(1c) during the study was positively correlated with changes per year in brachial-ankle pulse wave velocity (p = 0.00007) and resistive index (p = 0.0014) and was negatively correlated with that in blood flow (p < 0.0001) in diabetic patients.
Conclusions: Long-term hyperglycaemia is a major cause of impaired peripheral circulation in lower-leg arteries in diabetic patients without peripheral artery occlusive disease.