Comparison of Central Systolic Blood Pressure (Csbp) Estimated by Direct Central Blood Pressure (Dcbp) Formula and Radial Tonometry by Spigmocor: An Invasive Validation Study

Objective: Background: Arterial hypertension (AH) is the main risk factor for cardiovascular events for western populations. Blood pressure (BP) is usually measured at brachial artery level, but current evidence suggest that central blood pressure (cBP) could have a greater prognostic role. Recent studies showed that central Systolic BP (cSBP) can be reliably estimated by Direct Central Blood Pressure formula (DCBP = MBP2/DBP) using mean (MBP) and diastolic (DBP) blood pressure measured at brachial level. Aim: this study seeks to compare cSBP calculated using DCBP with cSBP estimated by radial tonometry (cSBPpwa) in comparison to SBP invasively measured (invSBP). Design and method: Methods: Consecutive patients who underwent invasive catheterization of the aorta and coronary arteries for clinical reasons were included. Using applanation tonometry with SphygmoCor device, cSBP was estimated by a generalized transfer function derived from radial pressure waveform calibrated to brachial SBP and DBP evaluated by oscillometric approach. Results: Results: We included 50 patients (66 ± 9.1 years, 74% men). The mean invSBP, cSBPpwa and DCBP were 140 ± 19.6, 134 ± 17.8 and 131 ± 16.7 mmHg respectively. The (DCBP-cSBPpwa) and (DCBP-invSBP) errors were -3.0 ± 11.9 and -9.6 ± 14.3 mmHg respectively. There was a linear relationship between invSBP and cSBPpwa, and invSBP and DCBP (R2 = 0. 783 and 0.490 respectively, p 130 mmHg: a cSBPpwa value of 129 and a DCBP value of 125.6 mmHg exhibited a sensitivity and a specificity of 13.3 and 22.9%, and 26.7 and 25.6% respectively in discriminating this threshold (Youden index = -0.638 and – 0.47; AUC 0.048 and 0.170 respectively). Conclusions: Conclusions: The DCBP formula allows for the estimation of invSBP worse than radial tonometry generalized transfer function, but better describing the risk of high central blood pressure values.