European Journal of Cardio-Thoracic Surgery, Vol 12, 873-875, Copyright © 1997 by European Association for Cardio-thoracic Surgery
Blood velocity patterns after aortic valve replacement with a pulmonary autograft
DA Steinbruchel, JM Hasenkam, H Nygaard, CM Riis and HH Sievers
Department of Cardiovascular Surgery, Medical University of Lubeck, Germany.
OBJECTIVE: Besides several other advantages, aortic valve replacement with
a pulmonary autograft may result in improved hemodynamic characteristics
compared to other valve replacement procedures. However, this plausible
assumption has never been verified. Therefore, the aim of this study was to
determine turbulent blood velocity energies in the ascending aorta after
aortic valve replacement with a pulmonary autograft. METHODS: Blood
velocity measurements were performed using a specialized pulsed Doppler
ultrasound technique in the ascending aorta immediately 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 allowed 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/m2 in all patients and in all measuring positions
in the cross sectional area. Color coded mapping of the spatial and
temporal turbulence energy distribution displayed no consistent areas with
markedly enhanced turbulence. These data are moderately elevated compared
to turbulence energy values for normal aortic valves, which are below 4
N/m2, while artificial or xenovalves typically show values in the range of
40-60 N/m2. 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
procedure provides excellent hemodynamic conditions in the ascending aorta.
