Introduction: central-to-peripheral systolic blood pressure (SBP) and pulse pressure (PP) amplification (SBP-amp, PP-amp) are independent predictors of cardiovascular events beyond brachial BP. The non-invasive estimation of central BP is limited by the differences between invasive brachial BP and cuff-based BP measurements. SBP-amp and PP-amp, given their independence from BP, are less influenced by brachial BP input errors.

Objective: to compare SBP-amp and PP-amp given by Omron HEM9000AI and SphygmoCor devices with invasive SBP-amp and PP-amp.

Methods: during coronary angiogram, invasive BP was measured in ascending aorta and in the brachial artery after pulling back a 6F fluid-filled catheter in 40 patients (66±12 years, 88% males). Simultaneously, radial waveform was acquired by the two devices contralaterally, and brachial BP was measured oscillometrically. Radial waveform was calibrated to brachial SBP/DBP. Radial-to-aortic transfer function (SphygmoCor) or the second systolic peak (HEM9000AI) were used for central BP estimation. Amplification was calculated as brachial BP/central BP.

Results: invasive aortic and brachial BP were 139/71±18/10 mmHg and 146/68±18/10 mmHg. Both devices underestimated central SBP (HEM9000AI -6±11 mmHg, SphygmoCor −18±9, both p<0.001). Invasive SBP-amp was 1.05±0.07 while invasive PP-amp was 1.18±0.19. HEM9000AI provided reasonable estimates of SBP-amp and PP-amp (ΔSBP-amp −0.01±0.08, ΔPP-amp −0.06±0.21, both p=n.s.), while SphygmoCor overestimated both SBP-amp and PP-amp (Δ vs invasive 0.08±0.07 and 0.15±0.16, both p<0.001, Figure).

Conclusions: SBP-amp and PP-amp non-invasively estimated by HEM9000AI was in line with invasive SBP-amp and PP-amp, while SphygmoCor overestimated SBP-amp and PP-amp. Systematic measurement errors or other variables may be responsible for the difference between the two devices.