It has been previously shown that average pulse pressure (PP), the systolic-diastolic blood pressure (BP) difference, measured with 24-hour ambulatory BP monitoring (24hABPM), can be expressed as a sum of two components: ‘elastic’ PP (elPP) and ‘stiffening’ PP (stPP) associated, respectively, with arterial stiffness (at the diastolic pressure) and its pressure dependence. The study objective was to determine PP, elPP and stPP (‘PP variables’) and assess their prognostic value in a large cohort of previously untreated subjects stratified by age and pulse rate (PR).
The study included untreated subjects assessed for hypertension in Dublin, Ireland, in whom 24hABPM records of adequate quality were obtained. The PP components were determined from the linear relationship between systolic- and diastolic BP using a model based on the nonlinear pressure-volume relationship in arteries that expresses stiffness-pressure relationship. Predictive power for cardiovascular (CV) mortality was expressed by hazard ratio (HR) determined using Cox regression models applied separately to PP and elPP & stPP (combined), adjusted for age, sex, BMI, smoking status, diabetes, previous CV disease, 24 h mean arterial pressure (MAP) and MAP dipping, and for the age and PR strata shown in the Table.
Of the 11,291 subjects included (age 54.4 ± 14.5, 47% male) 566 CV deaths occurred during the follow-up period (mean 5.8 years). Mean ± SD of PP, elPP and stPP were, respectively, 56.6 ± 12.4, 49.0 ± 9.8, and 7.6 ± 6.9 mmHg, and elPP and stPP were uncorrelated (r = 0.075). Table shows that the predictive power of elPP increased progressively with ageing, mainly for low PR. For age>=65 years elPP had greater predictive power than PP and stPP, especially for low PR. In contrast, for age < 50 and high PR, PP and stPP were stronger predictors than elPP, and for low PR none of PP variables had significant predictive power.
PP components derived from 24hABPM may have greater predictive power for CV death than PP itself in elderly subjects. Studies investigating occurrence of an independent association of PP components with additional fatalities are required in order to demonstrate the specificity of these new measures.
1Yazmonit Ltd. Department of R&D, Eshtaol, Israel
2Department Cardiology, Ospedale San Luca, Istituto Auxologico Italiano, Milan, Italy
3Connolly Hospital, Blanchardstown, Dublin, Ireland
4University College Dublin, Dublin, Ireland
5Department Cardiology, Ist. Auxologico Italiano & Department of Clin. Med and Prev. University Milano-Bicocca, Milan, Italy