Abnormal peripheral circulation in type 2 diabetic patients with normal ankle-brachial index associates with coronary atherosclerosis, large artery stiffness, and peripheral vascular resistance

We tested the hypothesis that impaired peripheral circulation in diabetes arises from different aspects of vascular abnormalities even when accompanied by a normal ankle-brachial index (ABI > 0.9). One hundred fourteen type 2 diabetic patients with normal ABI and 33 age-matched non-diabetic subjects consecutively admitted to our hospital were enrolled. The Agatston coronary artery calcium score (CACS), as a marker of coronary atherosclerosis, was obtained using electron-beam computed tomography. An automatic device was used to measure brachial-ankle pulse wave velocity (baPWV) as an index of arterial distensibility. Total flow volume and resistive index (RI), as a marker of peripheral vascular resistance, at the popliteal artery were evaluated using gated two-dimensional cine-mode phase-contrast magnetic resonance imaging. Diabetic patients had baPWV (P < 0.001) and RI (P < 0.001) higher than those in the non-diabetic subjects, indicating that those parameters are characteristically altered in diabetic patients. When diabetic patients were grouped into three subgroups according to their levels of total flow volume, those with the lowest range showed the highest log-transformed CACS (P < 0.001), baPWV (P < 0.001), and RI (P < 0.001) among the groups. Total flow volume was negatively correlated with log-transformed CACS (P < 0.001), baPWV (P < 0.001), and RI (P < 0.001). Waveform at the popliteal artery could be clearly separated into systolic and early and late diastolic blood flows, which were negatively correlated with log-transformed CACS (P < 0.001), RI (P < 0.001), and baPWV (P < 0.001), respectively. These results suggest that impaired peripheral circulation in diabetes is attributable to coronary atherosclerosis, large artery stiffness, and peripheral vascular resistance even when ABI is normal.