Pulse Wave Calibration and Implications for Blood Pressure Measurement: Systematic Review and Meta-Analysis

Central aortic systolic pressure (CASP) can be estimated via filtering of the peripheral pulse wave (PPW) following calibration to brachial blood pressure. Recent studies suggest PPW calibration to mean arterial pressure (MAP) and diastolic BP (DBP) provides more accurate CASP estimates (CASP MD ) versus conventional calibration to systolic BP (SBP) and DBP (CASP SD ). However, the peak of the MAP-DBP calibrated PPW, that is, SBP MD , is rarely reported or used for BP amplification calculations, despite CASP MD being derived from it. We aimed to calculate the unreported SBP MD from studies using MAP-DBP calibration for estimation of CASP MD and compared it with oscillometric brachial SBP (brSBP). Medline database was searched to March 18, 2020. Meta-analysis includes studies reporting noninvasive CASP SD , CASP MD , brSBP, and brachial DBP. SBP MD was calculated using linear function equations. Data from 21 studies used 8 different BP monitors (13 460 participants, mean age: 54±10 years, 57% female, brachial blood pressure: 130±14/79±9 mm Hg). Weighted mean difference between SBP MD and brSBP was 10 mm Hg (range, −2 to 17 mm Hg) and appeared device specific. Calibration of brachial versus radial PPWs to brachial blood pressure showed a greater disparity between SBP MD and brSBP (14 versus 2 mm Hg). BP amplification was similar comparing SBP-DBP versus MAP-DBP calibrations (brSBP-CASP SD versus SBP MD -CASP MD : 9 versus 11 mm Hg), with no instances of reverse BP amplification. PPWs calibrated to MAP-DBP to derive CASP MD generates SBP MD that differs markedly from brSBP with some oscillometric BP monitors. These findings have important implications for BP monitor accuracy, BP amplification, PPW calibration recommendations, and studies of associations between CASP versus SBP and outcomes.