In vitro 4D Flow MRI evaluation of aortic valve replacements reveals disturbed flow distal to biological but not to mechanical valves.

Autor: Oechtering TH; Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany., Sieren M; Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany., Schubert K; Department of Cardiac and Thoracic Vascular Surgery, University Hospital Schleswig-Holstein, Lübeck, Germany., Schaller T; Department of Cardiac and Thoracic Vascular Surgery, University Hospital Schleswig-Holstein, Lübeck, Germany., Scharfschwerdt M; Department of Cardiac and Thoracic Vascular Surgery, University Hospital Schleswig-Holstein, Lübeck, Germany., Panagiotopoulos A; Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany., Fujita B; Department of Cardiac and Thoracic Vascular Surgery, University Hospital Schleswig-Holstein, Lübeck, Germany., Auer C; Department of Cardiac and Thoracic Vascular Surgery, University Hospital Schleswig-Holstein, Lübeck, Germany., Barkhausen J; Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany., Ensminger S; Department of Cardiac and Thoracic Vascular Surgery, University Hospital Schleswig-Holstein, Lübeck, Germany., Sievers HH; Department of Cardiac and Thoracic Vascular Surgery, University Hospital Schleswig-Holstein, Lübeck, Germany., Frydrychowicz A; Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Lübeck, Germany.
Jazyk: angličtina
Zdroj: Journal of cardiac surgery [J Card Surg] 2019 Dec; Vol. 34 (12), pp. 1452-1457. Date of Electronic Publication: 2019 Oct 22.
DOI: 10.1111/jocs.14253
Abstrakt: Background and Aim of the Study: Aortic hemodynamics influence the integrity of the vessel wall and cardiac afterload. The aim of this study was to compare hemodynamics distal to biological (BV) and mechanical aortic valve (MV) replacements by in vitro 4D Flow MRI excluding confounding factors of in-vivo testing potentially influencing hemodynamics.
Methods: Two BV (Perimount MagnaEase [Carpentier-Edwards], Trifecta [Abbott]) and two MV (On-X [CryoLife], prototype trileaflet valve) were scanned in a flexible aortic phantom at 3T using a recommended 4D Flow MR sequence. A triphasic aortic flow profile with blood-mimicking fluid was established. Using GTFlow (Gyrotools), area and velocity of the ejection jet were measured. Presence and extent of sinus vortices and secondary flow patterns were graded on a 0 to 3 scale.
Results: A narrow, accelerated central ejection jet (Area = 27 ± 7% of vessel area, Velocity = 166 ± 13 cm/s; measured at sinotubular junction) was observed in BV as compared to MV (Area = 53 ± 13%, Velocity = 109 ± 21 cm/s). As opposed to MV, the jet distal to BV impacted the outer curvature of the ascending aorta and resulted in large secondary flow patterns (BV: n = 4, grades 3, 3, 2, 1; MV: n = 1, grade 1). Sinus vortices only formed distal to MV. Although physiologically configured, they were larger than normal (grade 3).
Conclusions: In contrast to mechanical valves, biological valve replacements induced accelerated and increased flow patterns deviating from physiological ones. While it remains speculative whether this increases the risk of aneurysm formation through wall shear stress changes, findings are contrasted by almost no secondary flow patterns and typical, near-physiological sinus vortex formation distal to mechanical valves.
(© 2019 Wiley Periodicals, Inc.)
Databáze: MEDLINE
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