Tonometric and Oscillometric Methods for Measurement of Central Blood Pressure Parameters: a Comparison in Patients with Borderline Hypertension or Stage 1 Hypertension

Abstract

Background: Changes in arterial compliance are among the first changes detectable in hypertensive syndrome. Methods with good reproducibility as compared with the gold standard for identifying such changes are desirable in clinical practice. Objectives: To compare central pressure measurements and arterial stiffness obtained by two non-invasive methods (tonometry and oscillometry). Methods: This was a descriptive, cross-sectional study with a convenience sample of patients with borderline hypertension or stage 1 hypertension. Peripheral and central blood pressure measurements were obtained by tonometry (SphygmoCor®), considered the gold standard, and oscillometry (Mobil O´graph®). Comparisons of results were made by unpaired t-test, and p values < 0.05 were considered statistically significant. Results: No difference was found in central pressure measurements obtained by SphygmoCor® (117 x 80.1 mmHg) compared with Mobil O'graph (112 x 81.4 mmHg). Mean augmentation index (AIx) was 26.1% and 21.3%, and mean pulse pressure (PP) amplification 10.7 mmHg and 10.0 mmHg by Sphygmocor® and Mobil O´graph®, respectively (p > 0.05). Mean pressure wave velocity (PWV), 8.4 m/s vs. 7.4 m/s (p = 0.013) and mean central pulse pressure, 37.7 mmmHg and 30.9 mmHg (p = 0.013) were significantly higher by SphygmoCor® than Mobil O´graph®. Conclusion: Values of central systolic blood pressure, AIx and pulse pressure amplification obtained by oscillometry were not statistically different compared with tonometry; values of PWV and cPP, however, were underestimated by oscillometry.