title: [Instantaneous blood flow velocity profiles before and after aortic valve replacement (author's transl)].
abstract: In 17 patients the instantaneous velocity profile was recorded before and after aortic valve replacement (Starr-Edwards, Björk-Shiley, Lillehei-Kaster). A single gated pulsed Doppler Ultrasonic flownmeter was used for analysis. Distal of these valves a flat flow profile was recorded showing high velocity gradients near the walls. As a main cause of this, numerous eddies and turbulent flow have been suggested. Downstream of a Starr valve a flat profile appears with a slowing down of forward flow just behind the ball. The disk valves Lillehei-Kaster and Björk-Shiley demonstrated a higher flow velocity in direction to the larger opening. The "in vivo" studies have been supported by "in vitro" measurements. The highest flow velocities were above 100 cm/sec and thus, according to Reynolds definition, in the turbulent range. The turbulent flow produces a washing effect, which is emphasized during the cardiac cycle. The importance of these data can be discussed by clinical results only.
mesh_terms: D001011:Aorta / Q000502:physiology* / Q000503:physiopathology; D001022:Aortic Valve Insufficiency / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000503:physiopathology; D001783:Blood Flow Velocity; D003326:Coronary Circulation; D004301:Doppler Effect; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011474:Prosthesis Design; D012039:Regional Blood Flow; D012212:Rheology; D014463:Ultrasonography
vernacular_title: Das Strömungsprofil in der Aorta vor und nach Herzklappenersatz