Validity and reliability of central blood pressure estimated by upper arm oscillometric cuff pressure

Background Noninvasive central blood pressure (BP) independently predicts mortality, but current methods are operator-dependent, requiring skill to obtain quality recordings. The aims of this study were first, to determine the validity of an automatic, upper arm oscillometric cuff method for estimating central BP (OCBP) by comparison with the noninvasive reference standard of radial tonometry (TCBP). Second, we determined the intratest and intertest reliability of OCBP. Methods To assess validity, central BP was estimated by OCBP (Pulsecor R6.5B monitor) and compared with TCBP (SphygmoCor) in 47 participants free from cardiovascular disease (aged 57 ± 9 years) in supine, seated, and standing positions. Brachial mean arterial pressure (MAP) and diastolic BP (DBP) from the OCBP device were used to calibrate in both devices. Duplicate measures were recorded in each position on the same day to assess intratest reliability, and participants returned within 10 ± 7 days for repeat measurements to assess intertest reliability. Results There was a strong intraclass correlation (ICC = 0.987, P < 0.001) and small mean difference (1.2 ± 2.2 mm Hg) for central systolic BP (SBP) determined by OCBP compared with TCBP. Ninety-six percent of all comparisons (n = 495 acceptable recordings) were within 5 mm Hg. With respect to reliability, there were strong correlations but higher limits of agreement for the intratest (ICC = 0.975, P < 0.001, mean difference 0.6 ± 4.5 mm Hg) and intertest (ICC = 0.895, P < 0.001, mean difference 4.3 ± 8.0 mm Hg) comparisons. Conclusions Estimation of central SBP using cuff oscillometry is comparable to radial tonometry and has good reproducibility. As a noninvasive, relatively operator-independent method, OCBP may be as useful as TCBP for estimating central BP in clinical practice.