Ambulatory blood pressure and coronary artery calcification in middle-aged and younger adults

Abstract

Background The objective of this study was to investigate relationships between blood pressure (BP) determined by ambulatory monitoring and coronary artery calcification (CAC) determined by electron beam computed tomography (EBCT) in middle-aged and younger adults without symptoms of coronary artery disease. Methods Measures of office and ambulatory BP were analyzed in 298 asymptomatic adults (134 women and 164 men) from the white population of Rochester, MN, who were 20 to 60 years old (mean ± SD, 40 ± 9 years). For the ambulatory BP measurements, the active period of the day was defined as the daytime, out-of-bed hours and the inactive period as the nighttime, in-bed hours. Logistic regression was used to assess whether ambulatory measures of BP influenced the probability of having CAC detected by EBCT. Results After adjusting for sex, age, and office measures of BP, ambulatory diastolic BP during the active and inactive periods were each statistically significant additional predictors of the probability of having CAC. Similarly, after adjusting for sex, age, and ambulatory systolic BP, ambulatory diastolic BPs during each period were also statistically significant additional predictors of the probability of having CAC. In contrast, measures of ambulatory systolic BP, pulse pressure, and diurnal dipping of BP levels from the active to the inactive period did not make statistically significant additional contributions to the probability of having CAC. Conclusion These findings emphasize the role that the hemodynamic stress of diastolic BP may play in the early development of atherosclerotic coronary artery disease.