Systolic BP Amplification: Systematic Review and Individual Participant Meta-Analysis.

Abstract

BACKGROUND Systolic blood pressure (SBP) amplification is a physiological phenomenon related to the level of pressure difference between the aorta and brachial artery and is associated with cuff blood pressure (BP) measurement inaccuracy. However, knowledge on the invasively measured level of aortic-to-brachial SBP amplification is limited. This study aimed to explore this, as well as anticipated effects on hypertension classification. METHODS A systematic review and individual participant data meta-analysis identified invasive brachial and aortic BP recorded in 1151 participants (62±12 years, 72% male). SBP amplification was calculated as brachial SBP minus aortic SBP. Hypertension classification (defined according to previously described thresholds for brachial and aortic BP) was compared between the aortic and brachial BP measures. RESULTS There was a wide range of SBP amplification, which was similar between male and female (mean±SD, 8±9 mm Hg and 7±10 mm Hg, respectively) and decreased with increasing age. High SBP amplification (>15 mm Hg) was observed in 17.4% (male, 16.8% versus female, 19.5%; P=0.44), and low SBP amplification (<5 mm Hg) in 37.3% of participants (male, 37.2% versus female, 37.4%; P=0.95). The overall level of agreement between hypertension classification based on brachial and aortic BP was moderate (κ, 0.67; P<0.001; agreement, 87.4%). Agreement in hypertension classification was 65.0%, 38.1%, and 92.7% across classifications of optimal, prehypertension, and hypertension, respectively. CONCLUSIONS In males and females there is wide variability in aortic-to-brachial SBP amplification. There were major theoretical differences in hypertension classification based on brachial versus aortic BP. This knowledge may help toward innovations for improving cuff BP measurement accuracy.