2. DECELERATION TIME OF THE LEFT VENTRICULAR OUTFLOW TRACT FLOW VELOCITY: A SURROGATE DOPPLER ECHOCARDIOGRAPHIC PARAMETER FOR CENTRAL PULSE PRESSURE

Abstract

Background: Central pulse pressure (PP) is an independent predictor of cardiovascular outcomes. However, a Doppler echocardiographic parameter reflecting central PP and arterial stiffness is not known yet. The aim of this study was to evaluate whether the left ventricular outflow tract (LVOT) flow deceleration is correlated with central PP and parameters of arterial stiffness. Methods: In 175 subjects (65 men, mean age 57 years), transthoracic echocardiogram and radial artery tonometry were simultaneously performed. The patients who had left ventricular (LV) systolic dysfunction, significant arrhythmia, valvular disease, coronary artery disease and renal insufficiency were excluded. The blood flow velocities through the LVOT were recorded using conventional pulsed Doppler and deceleration time (DT) of LVOT flow was measured. Central hemodynamics including central PP, pressure augmentation and augmentation index were noninvasively measured using radial artery tonometry. PP amplification was defined as the ratio of peripheral to central PP. Results: DT was significantly correlated with peripheral PP (r=0.23, p=0.002). However, it showed stronger positive correlation with central PP (r=0.44, p<0.001), pressure augmentation (r=0.50, p<0.001) and negative correlation with PP amplification (r=-0.33, p<0.001). Multiple linear regression analysis, controlled for variables such as age, gender, height, peripheral diastolic blood pressure, heart rate and LV ejection fraction, revealed an independent and significant strong correlation between LVOT DT and central PP (β = 0.34, p=0.001). Conclusion: DT of the LVOT flow velocity is a surrogate Doppler echocardiographic parameter for central PP. Prolonged LVOT DT would be a useful parameter to detect reduced compliance of a central artery.