Diagnostic accuracy of ankle-brachial index measurement in peripheral Arterial disease in TurkishAdults: A comparison with angiography

Objective: This study aims to assess the sensitivity and specificity of ankle-brachial index (ABI) measurements in diagnosing peripheral artery disease (PAD) among a cohort of Turkish subjects, with angiography serving as the reference standard. Material and Methods: In this single-center, cross-sectional and observational study, subjects who had an aorta and lower extremity arterial imaging by angiography subsequently underwent an ABI measurement. Anthropometric measurements, cardiovascular risk factors, and blood biochemistry data were recorded. Sensitivity and specificity analyses were performed for a low ankle-brachial index (ABI ≤ 0.9), with angiography as the reference standard. Results: A total of 57 patients (age: 59.1±15.9, male/female: 47/10) were included. Diabetes mellitus, coronary artery disease and cerebrovascular disease were present in 40.4%, 42.1% and 15.8% of the participants, respectively. Three or more cardiovascular risk factors were present in 54.4%. The angiographic diagnostic method was computed tomography angiography in 57.9%, digital subtraction angiography in 38.6%, and magnetic resonance angiography in 3.5% of the subjects. The presence of PAD on angiography was documented in 55 of 57 participants. The calculated mean ABI value was 0.6±0.2 in the overall group, and a low ABI (≤0.9) was found by 82.5% (n = 47). Compared to angiography, the low ankle-brachial index (ABI) test demonstrated a sensitivity of 83.6% and a specificity of 50%. The positive predictive value of 97.9% was calculated. When an ABI≤0.95 was used as the diagnostic threshold, the sensitivity of the ABI test increased to 90.9%. Conclusion: Our study confirms the reliability of ABI measurements as a diagnostic method for lower extremity peripheral artery disease (PAD) when compared to angiographic techniques, the gold standard. Establishing a higher cut-off value (≤0.95) may enhance the diagnostic performance of the test in Turkish patients.