Objectives: Endothelial dysfunction is associated to cardiovascular risk factors and predicts cardiovascular events. Peripheral arterial tonometry (PAT) is a novel noninvasive method to assess endothelial function. However, there is a paucity of data about its reproducibility. The aim of this study was to assess the feasibility and reproducibility of PAT in adults.
Methods: PAT exams were performed twice in the same day in 123 participants of a cohort about the determinants of diabetes and cardiovascular diseases (Brazilian Longitudinal Study of Adult Health--ELSA-Brasil). The interval between the exams was 2-6 h (mean=4 h). Endothelial function in PAT method is measured by reactive hyperemia index (RHI), which evaluates arterial pulsatile volume changes in response to hyperemia. Agreement of RHI values was compared by Bland-Altman method, coefficient of variation and coefficient of repeatability. Reliability was assessed by intraclass correlation coefficient (ICC).
Results: Mean values of RHI did not differ significantly between the exams of each participant (1.92±0.56 vs. 1.96±0.58, P=0.48). There were no systematic errors between the exams (mean of differences=-0.03±0.5). Measurement error was 0.35, coefficient of variation was 18.0% and ICC was 0.61. Sex, age or the presence of obesity did not have a considerable influence on the reproducibility of PAT.
Conclusion: PAT exam is feasible and has acceptable reproducibility in adults when compared with other noninvasive methods for endothelial function assessment. This performance makes PAT a promising method for future clinical and epidemiological studies.