COMPARISON OF LOWER-LIMB ARTERIAL ASSESSMENTS USING COLOR-DUPLEX ULTRASOUND AND ANKLE BRACHIAL PRESSURE INDEX MEASUREMENTS

The strength of agreement between two noninvasive methods of assessing lower limb arterial disease and their relationship to patient symptom s following exercise have been investigated. Color-duplex ultrasound ( CDU) and ankle/brachial pressure index (ABPI) (before and after exerci se) measurements were obtained from 200 consecutive patients referred to a vascular investigations laboratory. From these patients, 290 limb s were available for study, comprising limbs without previous vascular surgery, from patients without diabetes and who could attempt a walki ng exercise test. The overall level of agreement between CDU and resti ng ABPI measurements was 83% (Kappa 0.66). The ABPI technique identifi ed the more serious disease; a resting ABPI of less than 0.6 gave 100% agreement with CDU. With higher resting ABPIs the level of agreement became poorer: 83% (0.6 less than or equal to ABPI < 0.9) and 76% (nor mal ABPI greater than or equal to 0.9). The addition of postexercise A BPI measurements in determining significant arterial disease increased the strength of relationship between the two techniques by only 2% (8 5%, Kappa 0.69). The exercise test was generally limited by the most s ymptomatic limb in each patient, and the agreement between CDU and pos texercise ABPI measurements in these limbs was higher at 93% (Kappa 0. 81). In comparison, agreement for the least symptomatic group of limbs was found to be poor (69%, Kappa 0.37). Compared with symptoms after exercise, overall agreements with CDU and ABPI were both 67% (Kappa 0. 27). The agreement was better (91%) when the resting ABPI was less tha n 0.6. The ABPI is biased toward the detection of more severe disease and is more consistent with CDU when the most symptomatic limbs are co mpared. The relationship between either test and symptoms after exerci se is strong only for limbs with major disease.