Accuracy of commercial devices and methods for noninvasive estimation of aortic systolic blood pressure a systematic review and meta-analysis of invasive validation studies

Background: Although compelling evidence has established the physiological and clinical relevance of aortic SBP (a-SBP), no consensus exists regarding the validity of the available methods/techniques that noninvasively measure it. Objectives: The systematic review and meta-analysis aimed to determine the accuracy of commercial devices estimating a-SBP noninvasively, which have been validated by invasive measurement of a-SBP. Moreover their optimal mode of application, in terms of calibration, as well as specific technique and arterial site of pulse wave acquisition were further investigated. Methods: The study was performed according to the PRISMA guidelines; 22 eligible studies were included, which validated invasively 11 different commercial devices in 808 study participants. Results: Overall, the error in a-SBP estimation (estimated minus actual value) was -4.49mmHg [ 95% confidence interval (CI): -6.06 to -2.92 mmHg]. The estimated (noninvasive) a-SBP differed from the actual (invasive) value depending on calibration method: by -1.08mmHg (95% CI: -2.81, 0.65 mmHg) and by -5.81mmHg (95% CI: -7.79, -3.84 mmHg), when invasively and noninvasively measured brachial BP values were used respectively; by -1.83 mmHg, (95% CI: -3.32, -0.34 mmHg), and by 7.78mmHg (95% CI: -10.28, -5.28 mmHg), when brachial mean arterial pressure/DBP and SBP/DBP were used, respectively. Conclusion: Automated recording of waveforms, calibrated noninvasively by brachial mean arterial pressure/DBP values seems the most promising approach that can provide relatively more accurate, noninvasive estimation of a-SBP. It is still uncertain whether a specific device can be recommended as 'gold standard'; however, a consensus is currently demanding.