AIM: Ankle brachial index (ABI) is a diagnostic tool for peripheral arterial disease (PAD) and a cardiovascular risk stratification tool. Despite this evidence and guidelines recommending its use in everyday practice, ABI is not widely used. Automatic ABI measurement may lower the barrier to incorporate ABI measurement into everyday practice. The aim of this study was to validate a novel automatic oscillometric ABI device (BOSO ABI) against a gold standard-Doppler device in an epidemiological setting. METHODS: In 839 patients from the Czech post-MONICA study (a randomly selected representative population sample aged over 25 years), mean age 54.3±13.8 years (47% of men), ABI measurement was performed using the BOSO ABI device and a handheld Doppler device in a random fashion. The two techniques were carried out by different investigators each blinded to the findings of the other. Analyses were conducted as proposed by Bland and Altman. RESULTS: The mean ABI difference between the two methods was 0.1±0.11, with 95% limits of agreement ranging from -0.11 to 0.30. The difference between Doppler and oscillometric ABI increased significantly with increasing mean ABI (r=0.29; P<0.001). When considering Doppler the gold standard, automated oscillometric measurement had a 76.9% sensitivity, 97.9% specificity, and 37% positive and 99.6% negative predictive values in diagnosing ABI <0.9. CONCLUSION: The BOSO ABI device cannot be used interchangeably for standard Doppler ABI measurement in diagnosing PAD. However, its high negative predictive value allows using it as a screening tool for PAD.

Department of Preventive Cardiology Institute for Clinical and Experimental Medicine Prague Czech Republic