Anatomic correlates of supra-normal ankle brachial indices.

BACKGROUND: Supra-normal ankle brachial index (ABI) (>1.40), poses diagnostic challenges to determine the presence, location, and severity of peripheral artery disease (PAD). The anatomic distribution of PAD in patients with elevated ABI has not been previously described.

METHODS: A retrospective review of all patients referred to the Massachusetts General Hospital vascular diagnostic laboratory from 5 January 2006 to 12 January 2011 who had both a supra-normal ABI and contrast arteriography (CA) within 3 months of each other is reported. Angiographic patterns were described using the Trans Atlantic Inter Society Consensus II (TASC II) classification.

RESULTS: One-hundred sixteen limbs were analyzed in 92 patients. Mean age was 71.6 years (± 11.2); 81.5% (75/92) were male; 85.9% Caucasian (79/92); 67.4% diabetics (62/92); 78.3% hypertensive (72/92); 67.4% hypercholesterolemic (62/92); and 64.1% were current or former tobacco users (59/92). Chronic hemodialysis was present in 18.5% (17/92) and 15.2% (14/92) received chronic corticosteroids. Intermittent claudication was present in 46.7% (43/92) and critical limb ischemia in 52.2% (48/92). Aortoiliac, femoral and infra-popliteal involvement per angiography occurred in 14.9% (15/101), 56.1% (60/107), and 84.0% (84/100), respectively. Multilevel disease was present in 48.8% (42/86) of patients. PAD was absent in 4.7% (4/86) of patients. Toe brachial index <0.7 was found in 92% (92/100) of patients with angiographically confirmed PAD.

CONCLUSION: In symptomatic patients referred to a vascular laboratory who were found to have supra-normal ABI, nearly one half exhibited multilevel PAD, and over 80% had infrapopliteal involvement. A supra-normal ABI in such patients mandates evaluation for the presence and extent of PAD.