Background: Pulsatility index (PI) from transcranial Doppler sonography (TCD) reflects cerebral arterial resistance. Although several factors are known to be associated with the PI, precise correlation between PI and blood pressure has rarely been studied, particularly about the central blood pressure. Therefore, we aimed to find out possible correlations between the PI of basilar artery and several parameters reflecting central and peripheral blood pressure, and investigate which parameters are most likely used to predict PI. Methods: From July 2011 to October 2012, a total of 37 patients were enrolled. TCD examinaion on basilar artery and pulse wave analysis (PWA) were performed. The conventional atherosclerotic risk factors and parameters reflecting blood viscosity were also investigated. PWA was performed to obtain parameters reflecting central and peripheral blood pressure, and from the PWA, a novel index was named as pressure pulsatility index (PPI), which represented pulse pressure divided by mean blood pressure. Results: Several parameters revealed significant correlations between the PI; age, hemoglobin, hematocrit, augmentation pressure, diastolic blood pressure, pulse pressure, mean blood pressure and PPI, and the presence of diabetes mellitus. The hemoglobin, hematocrit, peripheral PPI and central PPI were also correlated with PI by age-adjusted correlation analysis. In stepwise multiple linear regression analysis, age (p=0.001) and central PPI (p=0.043) were independent variables that could predict the PI (R2=0.563). Conclusions: Among the several parameters reflecting blood pressure, central PPI showed strongest correlation with the PI. It suggests that systemic hemodynamic parameter derived from the PWA may be closely related to cerebral arterial pulsatility.

Journal of Neurosonology 5(1):24-29, 2013
Key Words: Transcranial doppler sonography, Pulsatility index, Aortic stiffness, Pulse pressure