Comparison of Lower Limb Arterial Assessments Using Color-Duplex Ultrasound and Ankle/Brachial Pressure Index Measurements

Abstract

The strength of agreement between two noninvasive methods of assessing lower limb arterial disease and their relationship to patient symptoms following exercise have been investigated. Color-duplex ultrasound (CDU) and ankle/brachial pressure index (ABPI) (before and afer exercise) measurements were obtained from 200 consecutive patients referred to a vascular investigations laboratory. From these patients, 290 limbs were available for study, comprising limbs without previous vascular surgery, from patients without diabetes and who could attempt a walking exercise test. The overall level of agreement between CDU and resting ABPI measurements was 83% (Kappa 0.66). The ABPI technique identified 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 < or = ABPI <0.9) and 76% (normal ABPI > or = 0.9). The addition of postexercise ABPI measurements in determining significant arterial disease increased the strength of relationship between the two techniques by only 2% (85%, Kappa 0.69). The exercise test was generally limited by the most symptomatic limb in each patient, and the agreement between CDU and postexercise 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 than 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 compared. The relationship between either test and symptoms after exercise is strong only for limbs with major disease.

A prospective comparison of bilateral photoplethysmography versus the ankle-brachial pressure index for detecting and quantifying lower limb peripheral arterial disease

“…The accuracy of the ABPI can be marginally improved by the inclusion of a standard treadmill exercise test and postexercise ABPI, and future studies should consider including this in their protocol. 31 Its accuracy can also be reduced in patients with calcified blood vessels, such as in those with diabetes or chronic renal failure, although this did not appear to be a problem in our study because less than half of the 7% subjects who had a raised ABPI of Ͼ1.3 in either leg had these diseases. We do, of course, recognize that calcification would be an issue for general PAD screening, and it would therefore be appropriate to evaluate this further in future studies.…”

“…Future research could also assess modified ABPI calculations that have recently been reported to improve the sensitivity of PAD detection. 32 Other diagnostic references that could have been used to evaluate the PPG technology include color-coded duplex ultrasound imaging with 83% agreement with resting ABPI 31 and also contrast-enhanced magnetic resonance angiography. 33 Although these imaging-based assessments are costly and resource intensive, they would have the advantage over ABPI in that they can provide some additional information about disease location.…”

Ankle Brachial Pressure Index (ABPI): An update for practitioners

“…The theoretical basis of ABPI is supported by obtaining ABPI ratios against findings in peripheral angiography,19–24 as well as from Doppler ultrasound as gold standard 25…”

Carotid intima-media thickness: Current evidence, practices, and Indian experience

“…ABPI was biased in the detection of more severe disease and its utility in patients with low-grade stenosis and with high-risk of heavy arterial calcification was unreliable. [1314] All these techniques were limited primarily because of the non-linear relationship between CV risk factors and the actual development of disease, their high cost, invasiveness, limited availability, advanced setup requirements, exposure to radiation and contrast, and decreased sensitivity and specificity. These factors posed a greater challenge in diagnosing atherosclerosis in low-risk individuals who may otherwise not require aggressive treatment.…”