Evaluation of the Vicorder, a novel cuff-based device for the noninvasive estimation of central blood pressure

Objectives: The Vicorder is a new brachial cuff-based device that estimates central blood pressure (cBP) using a brachial-to-aortic transfer function. The aim of this study was to evaluate cBP estimated by the Vicorder. Methods: During cardiac angiography, cBP estimated by the Vicorder and the SphygmoCor was evaluated against simultaneous invasive cBP in 50 patients. The two devices were also compared noninvasively in a separate group of 90 healthy individuals. Results: Central SBP (cSBP) obtained with each device satisfied the American Association for the Advancement of Medical Instrumentation accuracy criteria when peripheral waveforms were calibrated to invasive mean arterial pressure (MAP)/DBP: estimated - invasive cSBP difference, -4.0 +/- 7.4mmHg, Vicorder, P < 0.001; -1.4 +/- 7.9 mmHg, SphygmoCor, P = 0.21. When oscillometric brachial SBP/DBP was used for peripheral waveform calibration, cSBP was underestimated by Vicorder (Delta - 6.4 +/- 7.4mmHg, P < 0.001 versus invasive) and more so by SphygmoCor (Delta - 11.9 +/- 7.2mmHg, P < 0.001 versus invasive). Conversely, cSBP was more closely estimated by SphygmoCor when waveforms were calibrated to brachial MAP/DBP (Delta - 2.8 +/- 9.4 mmHg, P = 0.04 versus invasive). In the noninvasive study, Vicorder cSBP correlated well with SphygmoCor cSBP when SphygmoCor waveforms were calibrated to brachial MAP/DBP (121 +/- 16 versus 121 +/- 17 mmHg, P = 0.2) but not when brachial SBP/DBP was used for calibration (115 +/- 19 mmHg, P < 0.001). Conclusion: The Vicorder and SphygmoCor devices provide reliable estimates of cSBP when calibrated to invasive pressure. When calibrated to brachial BP, both devices underestimated cSBP, although this was attenuated when SphygmoCor was calibrated to brachial MAP/DBP. Vicorder may be a simple alternative to tonometry-based methods for noninvasive assessment of cBP.