Ankle brachial index and pneumoplethysmographic pulse-volume recordings for detection of peripheral arterial disease

The measurement of the ankle-brachial index (ABI) is a straightforward method for the detection of atherosclerosis in the lower limbs. Pneumoplethysmographic pulse-volume recordings (PVR) investigations are supposed to be less valid. Thus we compared the sensitivity of ABI and PVR in detection of PAD and its improvement by combining both methods. 122 consecutive patients admitted for PAD treatment were included. All patients (81 females; mean age 70 ± 15 years) had angiographic imaging of their peripheral arteries, a standardized personal interview and a determination of the ABI based on the highest (ABI high) and lowest (ABI low) ankle pressure. PVR parameters were oscillometric index (OI) and time to normalisation (TN) after exercise. There was a small variation of ABI with different segmental manifestations of PAD. The OI did not vary with different segmental manifestations. TN was longest in iliac artery manifestation and got shorter with more distal manifestation. Correlation of TN and ABI high and ABI low was low. Sensitivity of ABI high in all legs was 78 %, but only 40 % in isolated crural manifestation. ABI low has higher sensitivities with 87 % in all legs, but a much lower specificity. Combining ABI and TN increases both sensitivity and specificity. The best sensitivity and specificity was seen using ABI low + TN in combination in all kinds of manifestations with 94 % and 96 %, respectively. Combined assessment of ABI low and TN in post-exercise PVR seems to be a highly sensitive but also specific method to look for PAD compared to ABI high alone.