LAUSR

Objective: Accumulating evidence suggests that central (aortic) blood pressure (BP) may reflect the hemodynamic stress on target organs more accurately than brachial BP. However, the optimal method for the calibration of the brachial pressure waveform for the accurate assessment of the central BP is debatable. This study investigated the impact of the calibration mode (either with systolic and diastolic [C1] or the mean and diastolic brachial BP [C2]) on the association between ambulatory central BP and target-organ damage in young individuals. Design and method: Apparently healthy adolescents and young adults (age 12–25 years) referred for elevated BP and healthy volunteers were subjected to: (i) 24-hour ambulatory peripheral and central BP monitoring using a noninvasive brachial cuff-based oscillometric device (Mobil-O-Graph 24 h PWA); (ii) determination of left ventricular mass index (LVMI) and of the carotid intima-media thickness (cIMT). Results: Data from 99 subjects were analyzed (mean age 18.4 ± 4.5 years, 80 males, body mass index [BMI] 24.9 ± 5.2 kg/m2, 24 subjects with 24-hour brachial BP > = 95th percentile for adolescents or > = 130/80 mmHg for adults). 24-hour central C2 systolic/diastolic BP was higher than C1 (131.3 ± 13.7/73 ± 7.8 vs. 110.2 ± 9.5/72.5 ± 7.9 mmHg respectively, p < 0.05 for systolic/diastolic). Hypertensive compared to normotensive subjects presented higher values of both 24-hour central BP C2 (143.6 ± 12.5/82.6 ± 7.1 vs. 127.4 ± 11.7/70 ± 5.1 mmHg) and C1 (122.6 ± 7.9/82.2 ± 6.9 vs. 106.3 ± 5.8/69.3 ± 5.2 mmHg) (all p < 0.05). 24-hour central C2 vs. C1 systolic BP was more strongly associated with cIMT (r = 0.48 vs. 0.29 respectively, p < 0.05 for comparison), whereas no difference was observed in LVMI (r = 0.30 vs. 0.34 respectively, p = NS). In multivariate regression analyses (with age, gender, BMI and 24-hour central systolic BP as independent variables), the variation of cIMT was better determined when 24-hour central systolic BP C2 was included in the models as compared to C1 (improvement in the models’ R2 from 0.26 to 0.33). Conclusions: These data suggest that in young individuals the method selected for the calibration of the peripheral pressure waveform in 24-hour monitoring is important and affects the relationship between central BP and cIMT.