Comparison of Brachial Blood Pressure and Central Blood Pressure in Attended, Unattended, and Unattended Standing Situations

Central systolic blood pressure (cSBP) is an independent predictor of future cardiovascular disease. Unattended brachial SBP (bSBP) can eliminate the white-coat effect. However, unattended cSBP and unattended standing cSBP have never been reported. We aimed to compare bSBP and cSBP in attended, unattended, and unattended standing situations. We also aimed to compare the white-coat effect and unattended orthostatic BP change between bSBP and cSBP. Altogether, 104 hypertensive outpatients were included (mean age: 66.0 +/- 9.8 years, 41.3% male, mean body mass index: 25.0 +/- 4.5). Attended bSBP/cSBP values were 127.3 +/- 15.7/119.2 +/- 15.0, unattended bSBP/cSBP values were 122.7 +/- 15.3/114.4 +/- 15.1, and unattended standing bSBP/cSBP values were 123.6 +/- 15.7/114.1 +/- 14.8 mmHg (correlation coefficients/coefficients of determination between bSBP and cSBP: 0.971/0.943, 0.970/0.941, and 0.964/0.929, respectively; all p < 0.001). No significant difference was observed in the white-coat effect between bSBP and cSBP (4.6 +/- 5.8 vs. 4.8 +/- 5.7 mmHg). Although there was no significant difference between unattended sitting SBP and unattended standing SBP in terms of both bSBP and cSBP, a numerically small but significant difference was observed in the unattended orthostatic BP change between bSBP and cSBP (0.9 +/- 8.0 vs. -0.3 +/- 9.0 mmHg, p = 0.002). In conclusion, significant and strong correlations were observed between bSBP and cSBP in attended, unattended, and unattended standing BP measurements. The white-coat effect on bSBP was equivalent to that on cSBP. There was a numerically small but significant difference in the unattended orthostatic BP change between bSBP and cSBP.