Abstract 3008: Elevated Ankle Systolic Pressures and Peripheral Occlusive Arterial Disease in Diabetic and Non-Diabetic Subjects
Objective - The presence of a high ankle-brachial index (ABI) is due to calcified and stiff ankle arteries. New data suggest that this condition is prognostic of incident cardiovascular disease (CVD) events, similar to a low ABI. We analyzed risk factors related to a low (≤0.9) and high (≥1.4) ABI. Additionally, we studied the extent to which occlusive PAD coexists with high a ABI. We hypothesized that a substantial fraction of limbs with a high ABI would have PAD when assessed by other non-invasive means.
Methods- We studied 1003 available limbs of 510 study participants (37% were diabetic) who accepted the invitation to revisit the vascular laboratory for a comprehensive non-invasive assessment of lower limb arteries. ABI, toe-brachial index (TBI) and posterior tibial artery peak flow velocity (Pk-PT) were determined. A TBI >0.7 and a Pk-PT>10 cm/s were considered as normal. Data on smoking, diabetes, hypertension, dyslipidemia and CVD history were collected.
Results - High- and low-ABI were detected respectively in 2.1% and 47.5% of limbs. For an ABI≤0.9, age (OR=1.32 /10 years), Pack-years (OR=1.18 /20 pack-years) and hypertension (OR=1.83) were independent significant (P<0.001) factors. Diabetes was the only risk factor of high ABI (OR=14.5, P<0.001). When TBI and Pk-PT values were analyzed within ABI ranges, those with ABI≤0.9 and ABI≥1.4 presented similar patterns of abnormalities. Pk-PT and/or TBI was abnormal in more than 80% of cases in both ABI<0.9 and >1.4 groups, vs. only 35% in the 0.9–1.4 normal range (P<0.001). The ABI vs. TBI relationship appeared linear in non-diabetics, but was curvilinear in diabetics.
Conclusion - Diabetes is a singular risk factor for a high (≥1.4) ABI. Subjects with high ABI appear to have a large burden of underlying occlusive PAD in addition to calcified arteries.