A New Approach to Validate the Use of Brachial Blood Pressure to Assess Non-Invasive Aortic Pressure in Human Beings

Abstract

Introduction: It has been demonstrated that the noninvasive evaluation of aortic blood pressure has a prognostic value but limited by the inaccuracy linked to technical errors and a differences in the pressure wave analysis. Aims: The aim of this study was to compare two methods used to validate the non-invasively central blood pressure waveforms obtained with an oscillometic device, with those recorded by intra-arterial measurements at the aortic level. Methods: In this study were included 20 subjects, 10 males (68 ± 12-years-old, BMI: 27.4 ± 4.6 Kg/m2) and 10 females (77 ± 8-years-old, BMI: 28.5 ± 5.3 Kg/m2). The analysed cohort was composed of patients with diagnosis of coronary artery disease. Invasive and non-invasive data used in this research were previously analysed using a widely reported methodology and published by our group. The invasive aortic pressure recording was synchronically acquired with an oscillometric brachial acquisition and, then a reconstruction of central pressure wave was performed. In this research a correlation analysis using the entire aortic pressure cycle was performed. Results: Coefficient values found of the whole population, using the entire aortic pressure cycle, were similar to those obtained using the mean value of the cBP cardiac cycle (0.88 versus 0.89; respectively). On the contrary, the slope of the regression line determined by invasive versus noninvasive cBP loops (n = 20) using the entire cBP cycle exhibit a remarkable decrease with respect to that obtained using the mean aortic pressure cycle (0.98 versus 0.77). Conclusions: In a first step, applying an interpolation procedure by means of oversampling and digital low pass filter, we found a high correlation between invasive and noninvasive instantaneous aortic pressure waveforms in: Men, women and the whole population, In a second step, results in terms of correlation coefficient and the slope derived from the regression analysis of invasive and non-invasive using a new data analysis allow to confirm high correlation coefficients and a more realistic slope value of the invasive versus non-invasive pressure wave relationship.