The clinical applicability of an automated plethysmographic determination of the ankle-brachial index after vascular surgery

Abstract

An automated ankle-brachial index device could lead to potential time savings and more accuracy in ankle-brachial index-determination after vascular surgery. This prospective cross-sectional study compared postprocedural ankle-brachial indices measured by a manual method with ankle-brachial indices of an automated plethysmographic method. Forty-two patients were included. No significant difference in time performing a measurement was observed (1.1 min, 95% CI: −0.2 to +2.4; P = 0.095). Mean ankle-brachial index with the automated method was 0.105 higher (95% CI: 0.017 to 0.193; P = 0.020) than with the manual method, with limits of agreement of −0.376 and +0.587. Total variance amounted to 0.0759 and the correlation between both methods was 0.60. Reliability expressed as maximum absolute difference (95% level) between duplicate ankle-brachial index-measurements under identical conditions was 0.350 (manual) and 0.152 (automated), although not significant ( p = 0.053). Finally, the automated method had 34% points higher failure rate than the manual method. In conclusion based on this study, the automated ankle-brachial index-method seems not to be clinically applicable for measuring ankle-brachial index postoperatively in patients with vascular disease.