Abstract P209: Ambulatory Arterial Stiffness Index In Detecting Autonomic Failure

Abstract

Previous studies have shown standard deviation (SD) of daytime ambulatory systolic BP (DaySBP) as a screening tool for detecting autonomic failure. While ambulatory arterial stiffness index (AASI) has shown to be a predictor of cardiovascular morbidity and mortality, the usefulness of AASI in detecting the presence of autonomic failure has not been investigated. We assessed AASI in 336 hypertensive and normotensive adults with and without autonomic failure (ATF). Area under receiver operator characteristic curve (AUROC) was calculated to determine accuracy of AASI in detecting ATF. Bayes factor (BF) was used to assess the significance of the difference between AUROC of AASI compared to SD daytime SBP and AASI combined with SD daytime SBP compared to SD daytime SBP alone. Sensitivity and specificity of AASI in detecting autonomic failure was derived using cut-off points from Youden’s Index. Prevalence of ATF in our cohort was 14 % (47/336). The prevalence of HTN was 55 % (184/336). The mean age of the ATF group was higher than the control group (71 ± 11 vs. 61 ± 14 years, respectively, p < 0.05). The mean AASI of ATF patients was higher than control group (0.58 ± 0.11 vs. 0.51 ± 0.15, respectively, p < 0.05). The AUROC of AASI in ATF detection was not significantly higher than SD daytime SBP (BF =0.12). Sensitivity and specificity of AASI was 87 % and 43 %, respectively. The optimal cutoff for AASI selected by Youden’s index was 0.48. The addition of AASI to SD daytime SBP significantly improved ATF detection compared to AASI alone (BF > 3, Fig 1). In conclusion, AASI in combination with SD DaySBP significantly outperformed AASI alone in detecting autonomic failure in patients with or without HTN.