Técnica de bioimpedância aplicada à avaliação da rigidez arterial

Abstract

Cardiovascular diseases are mortality and morbidity factors in the most industrialized populations, with large arteries pathologies usually on their onset. Arterial stiffness, whose increase is related to factors like age, sex, atherosclerosis, and arterial hypertension, may be assessed by the Pulse Transit Time (PTT). This work developed a system to measure PTT with ECG’s R wave and the peak of bioimpedance from the radial artery, avoiding influences on the region’s hemodynamics, and applied it to 20 healthy young adults at rest and during hand immersion in water with ice, to check PTT and mean arterial pressure (MAP) variation in both phases. The bioimpedance signal was successfully validated by comparing its peaks’ and RR’s intervals, and by its smaller, but in the same order of magnitude of the literature (close to 20 mΩ, against 50-200 mΩ). All volunteers had statistically significant decrease in PTT and increase in MAP between phases, and the group averages were also different, (231.3 vs. 216.6 ms and 86,53 vs. 109.8 mmHg, respectively). After grouping PTT and MAP of both phases, we found a moderate and significative correlation (𝑟 = −0.39) between the variables. Besides, PTT and MAP were the most strongly related variables in multivariate linear models including anthropometric variables, both when PTT was the target and when MAP was the output.