Variation in Pulse Contour Markers on an Anesthetized Porcine During Pressure Perturbation: Association with Local and Regional Stiffness

Pulse contour analysis (PCA) provides detailed evaluations of the accelerative and decelerative phases of the arterial pulse waveform, potentially associated with large artery stiffness and vascular ageing. Previous studies have reported age-related associations (both structural and functional) with PCA markers and stiffness. However, changes in functional stiffness under a drug produced due to the interplay of blood pressure and heart rate were not explored. In this work, we investigate the variation of PCA markers derived from the second derivative of invasive pressure waveform recorded from the carotid artery of an anaesthetized porcine model under drug intervention. The variations in PCA markers are compared with the functional stiffness surrogates (pulse wave velocity (PWV) regional and local), which are clinically relevant markers that vary with blood pressure and heart rate. Local and regional PWV was measured from pulse transit time, obtained from the carotid artery for the former and carotid-femoral artery for the latter. Group average local and regional PWV varied at least by 83.26%, and group average PCA markers by 25.19% for a 57.75% change in pulse pressure. PCA markers: b/a and c/a had statistically significant highest correlation (r = 0.63, r = -0.93 respectively, p < 0.001) with local PWV and pulse pressure (r = 0.73, r = -0.97 respectively, p < 0.001), whereas c/a and d/a had statistically significant highest correlation (r = -0.96, r = -0.98 respectively, p < 0.001) with regional PWV. The study helps understand the selective associations of PCA markers (through multivariate regression analysis) on local, regional stiffness and pulse pressure. Such PCA markers potentially provide information useful for developing vascular index matrices.