Effectiveness of Four-Limb Blood Pressure in Distinguishing Between Aortic Stenosis and Bilateral Lower-Extremity Arterial Stenosis

In this study, we investigated the applicability of the ankle-brachial index (ABI) and brachial-ankle index (BAI) in distinguishing aortic stenosis (AS) from lower-extremity arterial stenosis. The difference between the ABI on both sides (∆ABI) was defined as the absolute value of the left ABI minus the right ABI. Lower BAI (L-BAI) was defined as the value of the side with the lowest BAI. We obtained four-limb blood pressure measurement data from 6435 patients. AS and bilateral lower-extremity arterial stenosis (BLEAS) were diagnosed. The performance of combined bilateral ABI decline, ΔABI, and L-BAI in diagnosing AS was evaluated. The control group showed normal bilateral ABI values, whereas the AS and BLEAS groups exhibited a bilateral ABI decline. The BLEAS group had the highest ∆ABI compared to the other groups. L-BAI in the BLEAS and AS groups was higher than that in the control group. AS screening using bilateral ABI ≤0.90 combined with ΔABI ≤0.10 and L-BAI >1.00 yielded an area under the receiver operating characteristic curve of 0.873 and a Youden index, sensitivity, and specificity of 0.724, 85.2%, and 87.2%, respectively. Validation in 1004 patients revealed a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 90.0%, 96.0%, 54.2%, 99.5%, and 95.7%, respectively. In conclusion, combining bilateral ABI ≤0.90, ∆ABI ≤0.10, and L-BAI >1.00 can effectively screen for AS; this is useful in distinguishing AS from BLEAS, especially in cases of bilateral decline in lower-extremity ABI values.