Correlation Between Ankle Brachial Index and Lower Limbs Digital Pulse Oximetry: A Referral Center Experience, Prevalence Study.

Objective Ankle-brachial index (ABI) is widely recommended and used to evaluate peripheral arterial disease. The oxygen saturation (SpO) has been associated with ABI, showing a promising clinical practice utility; however, little literature regarding this matter has been reported. This study aims to assess the correlation between pulse oximetry and ABI.  Methods A cross-sectional study was conducted using ABI measuring devices, such as the MESI® Ankle Brachial Pressure Index (ABPI) (MESI, Ltd., Slovenia, EU) and pulse oximetry. We compared the SpO distribution by using the Wilcoxon test and evaluated its correlation by using logistic regression.  Results From a total of 86 patients, 54 were males (62.8%) and the median age was 54 years old (interquartile range (IQR) = 37 - 65 yrs.). Regarding ABI measurements of the right lower limb (RLL), a total of 20 patients (22.3%) had an abnormal classification. On the other hand, a total of 21 patients (22.1%) had an abnormal classification of the left lower limb (LLL) ABI measurements. The distribution of SpO in relation to ABI categories was not statistically different (RLL p = 0.2433; LLL p = 0.1242). The SpO classification of ABI and abnormal pulse oximetry for the RLL was at 76.7% and at 77.9% in the LLL (Pearson's goodness-of-fit test: RLL = p < 0.001 and LLL = p < 0.001).  Conclusion Although we didn't observe any statistical differences in the SpO distribution regarding ABI measurements, in their correlation, there seems to be a different tendency. The SpO might be a useful non-invasive tool to assess asymptomatic patients with risk factors for peripheral arterial disease (PAD).