Evaluation of a Brachial Cuff and Suprasystolic Waveform Algorithm Method to Noninvasively Derive Central Blood Pressure

BACKGROUND: Central blood pressure (BP) can be estimated noninvasively by analyzing brachial artery waveforms. In this study, our aim was to assess the validity of a brachial cuff-based (suprasystolic) technique for estimating central BP (CBPestimated) by comparison with invasive aortic BP (CBPinvasive). METHODS: Eighty-four simultaneous CBPestimated (Pulsecor R7.0) and CBPinvasive measures were recorded in 47 patients (aged 63±10 years, 62% male) undergoing coronary angiography. Measures were captured at baseline and acutely following intravenous glyceryl trinitrate (GTN; 100-200 μg). Mean CBPinvasive systolic BP (SBP) and diastolic BP (DBP) were compared with CBPestimated SBP and DBP calibrated with brachial SBP and DBP recorded from the Pulsecor device. To test validity of the central BP algorithm, measures of CBPestimated SBP were also compared with CBPinvasive SBP following recalibration with invasive mean arterial pressure (MAP) and DBP. RESULTS: At baseline, mean difference ± standard deviation between CBPestimated SBP and CBPinvasive SBP was -7±9mm Hg (intraclass correlation coefficient (ICC) = 0.86; P < 0.001) with similar underestimation post-GTN (-6±9mm Hg; ICC = 0.90; P < 0.001). Recalibration of CBPestimated SBP with invasive MAP and DBP resulted in closer mean difference to CBPinvasive SBP (-2±7mm Hg; ICC = 0.95; P < 0.001) at baseline but not post-GTN (-6±7mm Hg; ICC = 0.95; P < 0.001). CONCLUSIONS: The Pulsecor algorithm to derive central BP has acceptable validity when calibrated with invasive pressures. However, accuracy is compromised when noninvasive brachial cuff BP calibration is used.