28 July 2008 - The ratio of central to peripheral pulse pressure (PP) is significantly increased in individuals with cardiovascular risk factors or established cardiovascular (CV) disease compared with in healthy individuals, say Carmel McEniery, MD (University of Cambridge, UK), and colleagues. The researchers add that central pressure measurement may ultimately improve the identification and management of patients with elevated CV risk.

PP varies throughout the arterial tree, driven mainly by differences in vessel stiffness and wave reflection between the central and peripheral vasculature and leading to a gradient between central and peripheral blood pressures, explains the investigators. Age, heart rate, and height have all already been shown to have differential influences on central and peripheral blood pressures (BP). McEniery and colleagues noted that CV risk factors such as hypercholesterolemia, hypertension, smoking, and the metabolic syndrome are likely to have greater effects on central than on peripheral pressures.

To investigate this further, the researchers analyzed seated peripheral (brachial) and central (aortic) BP for 10,613 adults aged between 18 and 101 years. The study group included healthy individuals, people with diabetes or CV disease, and individuals with just one of the cardiovascular risk factors hypercholesterolemia, hypertension, or smoking.

After adjustment for differences in age, height, and heart rate between groups, all of the CV risk factors and CV disease were associated with increased PP ratios in both men and women (p<0.001 for all comparisons). The authors note that, despite the age-related increase in PP ratio, even patients in the oldest age category (>80 years) showed significant disparity between aortic and brachial PPs, as reflected by average differences between aortic and brachial systolic BP of 11 and 8 mmHg in men and women, respectively.

Given that there was considerable variation in the PP ratio in the study group, the researchers stratified individuals by brachial systolic pressure to investigate the inter-individual variability in aortic systolic pressure. This revealed substantial overlap in aortic systolic pressures between categories, such that more than 70% of people classed with normal and high-normal blood pressure by brachial measurement had overlapping aortic systolic pressures.

McEniery and colleagues concludes: “These data demonstrate that cardiovascular risk factors affect the PP ratio, and that central pressure cannot be reliably inferred from peripheral pressure”.

Hypertension 2008;51:1476-1482