Out-of-office and central blood pressure for risk stratification: a cross-sectional study in patients treated for hypertension

Background: Central blood pressure (BP) predicts mortality independent of office brachial BP. Whether central BP may be useful to differentiate BP control requires examination and was the first aim of this study. Secondly, we sought to determine the variability in central BP among patients from different categories of BP control [controlled hypertension (CH), masked hypertension (MH), white coat (WCHT) and uncontrolled hypertension (UH)].

Materials and methods: We assessed patients with uncomplicated hypertension using measurement of central BP (SphygmoCor 8.1), brachial BP and 24-h ambulatory BP monitoring. BP control was defined according to guidelines using office BP and 24-h BP.

Results: Of the 201 patients (63 ± 8 years, 51% men), 67 (33%) were classified as CH; 59 (29%) with MH; 31 (15%) with WCHT; and 44 (22%) with UH. There were no differences in central BP parameters (augmentation pressure, augmentation index, pulse pressure) between patients with CH and MH or between patients with WCHT and UH (P > 0.05 for all). However, there was significant overlap in central systolic BP between BP control categories. For example, 27% of patients with normal brachial systolic BP had central systolic BP above age- and gender-specific normal values, including patients from three classifications of BP control (CH: n = 27; MH: n = 22; and WCHT: n = 4).

Conclusion: Office central BP alone cannot delineate categories of BP control. However, given the high degree of variability in central BP among patients from different categories of BP control, measurement of central BP may result in significant reclassification of risk related to BP.