CALF BLOOD FLOW AS A NON-INVASIVE PREDICTOR OF LIMB PERFUSION IN PERIPHERAL ARTERIAL DISEASE 1170

Abstract

A thallium graded exercise test (GXT) has been used to access lower limb perfusion in peripheral arterial disease (PAD) patients; however, this test is an invasive and costly procedure. Therefore, the purpose was to see if a less costly, non-invasive measure of calf perfusion would correlate with the more invasive thallium procedure. Eighteen PAD patients with a resting ankle/brachial systolic pressure index (ABI) of 0.60 ± 0.15 (Mean± SD) were recruited. All subjects underwent a GXT on a treadmill to maximum leg pain tolerance. Thallium was injected during the final minute of the GXT and then the lower extremities were scanned for thallium distribution. Peak calf blood flow (PCBF) was measured non-invasively by having the subjects perform toe raises to pain tolerance while leg blood flow was occluded with a thigh cuff. PCBF measurements were taken at 1 and 3 min post occlusion. A thallium index (ThI) was calculated as a ratio of the total count of calf area/gluteal area of the more severely diseased leg. The ThI for the group was 0.40 ± 0.13. The PCBF were 11.99 ± 4.84 ml/100 ml/min and 10.77± 3.81 ml/100 ml/min for the 1 and 3 minutes post, respectively. A lower ThI was related to lower PCBF at both 1 min (r=0.50, p<0.05) and 3 min (r=0.50, p<0.05) post occlusive exercise. It is concluded that PCBF is a valid predictor of lower limb perfusion in PAD patients.