BLOOD VELOCITY PATTERNS AFTER AORTIC-VALVE REPLACEMENT WITH A PULMONARY AUTOGRAFT

Objective: Besides several other advantages, aortic valve replacement with a pulmonary autograft may result in improved hemodynamic characte ristics compared to other valve replacement procedures. However, this plausible assumption has never been verified. Therefore, the aim of th is study was to determine turbulent blood velocity energies in the asc ending aorta after aortic valve replacement with a pulmonary autograft . Methods: Blood velocity measurements were performed using a speciali zed pulsed Doppler ultrasound technique in the ascending aorta immedia tely after weaning from extracorporeal circulation. Six patients were included in the study. Determination of radial velocity components in 17 measuring points evenly distributed in the cross sectional area all owed computation of turbulence energies and a quantitative display of the spatial and temporal turbulence energy distribution during systole . Results: The maximum turbulence energies were below 13 N/m(2) in all patients and in all measuring positions in the cross sectional area. Color coded mapping of the spatial and temporal turbulence energy dist ribution displayed no consistent areas with markedly enhanced turbulen ce. These data are moderately elevated compared to turbulence energy v alues for normal aortic valves, which are below 4 N/m(2), while artifi cial or xenovalves typically show values in the range of 40-60 N/m(2). Conclusions: Turbulence energy levels after aortic valve replacement with a pulmonary autograft are considerably lower than those found for artificial aortic valves. From a fluid dynamic point of view this pro cedure provides excellent hemodynamic conditions in the ascending aort a. (C) 1997 Elsevier Science B.V.