Can we boost screening for peripheral arterial disease?
Authors: Fendrik K , Endrei D , Biro K , Koltai K , Toth K , Kesmarky G 
Published: October 2022

Abstract

Despite the high prevalence of peripheral artery disease (PAD), the diagnosis is often delayed. The delayed diagnosis is due in part to comorbidities which can mask PAD symptoms, and in large part to the low use of conventional diagnostic tools. For PAD diagnostics, the guidelines recommend Doppler-based ankle-brachial index (ABI). The method is time consuming and requires skills. The toe pressure measurement which helps to eliminate the falsely elevated ankle pressures due to mediasclerosis is an almost neglected method for screening. In recent years, automatic, oscillometric four-limb blood pressure monitors have become available that provide data within minutes. We aimed to compare an automatic four limb blood pressure monitor with devices regularly used in our department.

Methods
Blood pressure was measured in 92 individuals (mean age 65±14 years) using a Doppler device (Hadeco) and a conventional manual sphygmomanometer on all four limbs, as well as an automatic, four-limb pressure monitor (BOSO ABI system-100 PWV) which also measured pulse wave velocity (PWV). Toe pressure was measured with a laser Doppler fluxmeter (Periflux 5000) and a photophlethysmography based toe pressure monitor (Systoe). Patients without known PAD but with at least one abnormal test result underwent a vascular imaging including ultrasound, CT or digital subtraction angiography. Among the 92 individuals there were patients with confirmed PAD, persons at high or very high cardiovascular risk, patients with non-ischaemic cardial diseases and healthy volunteers.

Results
ABI values of the posterior tibial artery at the corresponding side measured by Doppler and BOSO showed a strong correlation with each other (Pearson's r: 0.8 and 0.7), while the Doppler ABI values of the dorsal pedal artery showed a moderate or weak correlation with BOSO ABI values (r: 0.63 and 0.27). The toe pressure measured by laser Doppler and Systoe did not differ significantly. The ROC curve analysis of the Periflux TBI values supported 0.6 as a cut-off level (91.6% sensitivity, 84% specificity). Of the 52 individuals with high or very high cardiovascular risk, 15 with Doppler, 12 with BOSO and 29 with Periflux could be considered as abnormal, the vascular imaging confirmed PAD in 12 of them. Doppler ABI was abnormal in 96%, BOSO ABI in 69%, BOSO ABI combined with PWV in 92%, Periflux and Systoe toe brachial index (TBI) in 100–100% in 72 limbs with confirmed PAD. In control subjects, ABI, TBI, and PWV were normal; in subjects with high or very high risk, PWV was 58% abnormal, in confirmed PAD, 85%. All patients with abnormal PWV showed atherosclerotic lesions by the vascular imaging.

Summary
For detection of PAD, the measurement of TBI had the highest sensitivity. PAD screening of a large population may be possible using automatic four limb blood pressure monitors. By combining with additional features (e.g. PWV) the detection ratio can be improved to the level of the Doppler ABI method.

Funding Acknowledgement
Type of funding sources: None.