24-HOUR CENTRAL BLOOD PRESSURE

Objective: Central systolic blood pressure (cSBP) differs from peripheral SBP (pSBP) and may have higher prognostic relevance, but the normal values in ambulatory conditions are unknown. We present reference values for 24-hour central BP profiles, obtained in apparently healthy adult individuals from 20 centers in 14 countries and 5 continents, and compare the findings with peripheral BP. Design and method: 24-hour ambulatory BP monitoring, using a validated oscillometric device (Mobilograph, I.E.M, Stolberg, Germany), was performed in 2527 individuals (1206 men, 1321 women). Central pressures were assessed, using brachial waveforms, calibrated with mean/diastolic BP, and a transfer function. Participants were divided into 6 age groups (18–29, 30–39, 40–49, 50–59, 60–69, 70–99 years). Nighttime/daytime difference (N/D) was defined as nighttime (01.00 - 06.00) minus daytime (09.00 - 21.00) values / daytime values. Results: Averaged 24-hour central BP across all individuals was 128/79 mm Hg (daytime 128/81 mm Hg, nighttime 125/72 mm Hg), with slightly higher BP in men, compared to women. In contrast, central pulse pressure (PP; mean value 48 mm Hg, daytime 46 mm Hg, nighttime 52 mm Hg) was higher in women, compared to men. Mean values for cSBP, diastolic BP, and heart rate were highest in middle age, whereas mean values for cPP were highest in old age. Peripheral SBP N/D was −11% in the youngest age group, and decreased with increasing age, reaching −6% in the oldest age group. In contrast, cSBP N/D was less pronounced, even inverse (1 %) in the youngest age group, reaching −2 % in the oldest age group. Peripheral PP N/D was negligible across all age groups, and central PP N/D was inverse and highest (31 %) in the youngest age group. Conclusions: We provide reference values for apparently healthy individuals across the adult life span for central SBP and PP, comprising 24-hour mean BPs and 24-hour variability. Both differ from peripheral BP. These data may serve for comparison in various diseases and have potential implications for refining hypertension diagnosis and management