Rückwärtsbewegung und kleines Leck als Ursache. Mechanical valves have a normal regurgitant volume that may include either a backflow related to the backward motion of the occluder(s) (i.e. the closing volume), a leakage backflow through the components of the prosthesis (leakage volume) or both.7,14,80 – 82,94 – 96
Washing-Effekt. This ‘built-in’ regurgitation theoretically prevents blood stasis and thrombus formation by a washing effect. Minor regurgitation is thus normal in virtually all mechanical valves.
Am Ursprung eng, symmetrisch, langsamer Fluss. As opposed to pathologic regurgitant jets, the normal leakage backflow jets are characterized by being narrow at their origin and symmetrical and low in momentum (i.e. usually have a homogeneous colour without significant aliasing).
Kein erhöhter Vorwärtsfluss. They are also characterized by the absence of supporting features like increased anterograde velocity, enlargement of cardiac chambers, or pulmonary hypertension.
Bioprothese. Of note, mild central leakage may be seen in normally functioning bioprosthetic valves.7,14
Kugelprothese. ‘Caged-ball mechanical prostheses’ have a small amount of normal regurgitant flow (closing volume of 2–6 mL per beat).
Kippscheibe: ‘Monoleaflet mechanical’ valves have small physiologic regurgitant volume (5–9 mL per beat) that includes the closing volume as well leakage backflow through small gaps around the perimeter of the valve. In the Medtronic-Hall valves, there is also often a small amount of regurgitation around the central strut.
Doppelflügel mit 2 Jets + kleinem centralen. ‘Bileaflet mechanical valves’ typically have a small amount (5– 10 mL per beat) of normal regurgitation. On Doppler colour flow imaging, two main regurgitant jets originating from the pivot points of the valve disks which may break into one or more ‘plumes’ and a smaller central jet are often seen (Figure 2, Panel G and I ). Smaller jets around the closure rim of the leaflets may also be seen.
Perikard-Prothesen: A small degree of central (at the point of apposition or close to the commissures) regurgitation (,1 mL) is also often observed in ‘bioprosthetic valves’ and more frequently in bovine pericardial valves.
Bei stentfreie Prothesen häufiger. Stentless valves, including homografts and autografts, are more likely than stented valves to have minor regurgitant jets.
Lancellotti, Patrizio; Pibarot, Philippe; Chambers, John; Edvardsen, Thor; Delgado, Victoria; Dulgheru, Raluca et al. (2016): Recommendations for the imaging assessment of prosthetic heart valves: a report from the European Association of Cardiovascular Imaging endorsed by the Chinese Society of Echocardiography, the Inter-American Society of Echocardiography, and the Brazilian Department of Cardiovascular Imaging. In: European heart journal cardiovascular Imaging 17 (6), S. 589–590.