The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA.
EuroIntervention. 2017 Sep 20;13(7):811-819. doi: 10.4244/EIJ-D-17-00094.
There is an increasing awareness of leaflet thrombosis following transcatheter aortic valve implantation (TAVI) and valve-in-valve (ViV) procedures. Nevertheless, the predisposing factors affecting transcatheter aortic valve (TAV) thrombosis have remained unclear. This study aimed to quantify the effects of reduced cardiac output (CO) on blood stasis on the TAV leaflets as a permissive factor for valve thrombosis.
An idealised computational model representing a TAV was developed in a patient-specific geometry. Three-dimensional flow fields were obtained via a fluid-solid interaction modelling approach at different COs: 5.0, 3.5, 2.0 L/min. Blood residence time (BRT) was subsequently calculated on the leaflets. An association between reduced CO and increased blood stasis on the TAV leaflets was observed. At the end of diastole, larger areas of high BRT (>1.2 s) were observed at the leaflet's fixed edge at low COs. Such areas were calculated to be 2, 8, and 11% of the total surface area of leaflets at CO=5.0, 3.5, and 2.0 L/min, respectively, indicating a ~sixfold increase of BRT on the leaflets from the highest to the lowest CO.
This study indicates an association between reduced CO and increased blood stasis on the TAV leaflets which can be regarded as a precursor of valve thrombosis.
经导管主动脉瓣植入术（TAVI）和瓣中瓣（ViV）术后，人们对瓣叶血栓形成的认识日益提高。然而，影响经导管主动脉瓣（TAV）血栓形成的诱发因素仍不清楚。本研究旨在量化心输出量（CO）降低对 TAV 瓣叶血液淤滞的影响，将其作为瓣膜血栓形成的许可因素。
以患者特定的几何形状为基础，开发了一个代表 TAV 的理想计算模型。通过流固相互作用建模方法在不同 CO 下（5.0、3.5、2.0 L/min）获得三维流场。随后在瓣叶上计算血液停留时间（BRT）。观察到 CO 降低与 TAV 瓣叶血液淤滞增加之间存在关联。在舒张末期，在 CO 较低时，在瓣叶的固定边缘处观察到更大面积的高 BRT（>1.2 s）。在 CO=5.0、3.5 和 2.0 L/min 时，这些区域分别计算为瓣叶总面积的 2%、8%和 11%，表明从最高 CO 到最低 CO，瓣叶上的 BRT 增加了约六倍。
本研究表明 CO 降低与 TAV 瓣叶血液淤滞之间存在关联，可视为瓣膜血栓形成的前兆。
