Objective: Studies directly comparing the associations of intima-media thickness with blood pressure (BP) on manual sphygmomanometric blood pressure measurement (SBPM) and 24-h ambulatory blood pressure measurement (ABPM) are scarce and have a cross-sectional design.
Methods: At baseline, we measured systolic and diastolic blood pressures, pulse pressure, and mean arterial pressure in 532 randomly recruited patients (women, 48.3%; mean age, 38.9 years) by SBPM and ABPM. SBPM was the average of five consecutive readings obtained by trained observers at the patients' homes. We measured carotid intima-media thickness (CIMT) and femoral intima-media thickness (FIMT) by a wall-tracking ultrasound system, 26 months (median) after BP measurement (interquartile range, 21-29 months). We adjusted all analyses for observer, sex, age, BMI, smoking, and total/high-density lipoprotein-cholesterol ratio.
Results: The multivariable-adjusted associations of CIMT and FIMT with all BP components on SBPM were not significant (P >or= 0.12). In multivariable-adjusted models, CIMT increased with 24-h systolic blood pressure (effect size per SD increase, +0.131 mm; P = 0.003) and 24-h pulse pressure (+0.139 mm; P = 0.001), whereas FIMT increased with 24-h diastolic blood pressure (+0.091 mm; P = 0.03) and 24-h mean arterial pressure (+0.090 mm; P = 0.04). Models including the ambulatory blood pressure components additionally adjusted for SBPM and more covariables than those listed above were confirmatory.
Conclusion: In a general population, BP on ABPM predicts CIMT and FIMT over and beyond highly standardized SBPM. At the elastic carotid artery, CIMT increased predominantly with the pulsatile component of BP, whereas at the muscular femoral artery, FIMT increased with the steady component of BP.