Objectives

Thrombosis is a leading cause of failure for cardiovascular devices. While computational simulations are a powerful tool to predict thrombosis and evaluate the risk for medical devices, limited experimental data are available to validate the simulations. The aim of the current study is to provide experimental data of a growing thrombus for device-induced thrombosis.

Materials and methods

Thrombosis within a backward-facing step (BFS), or sudden expansion was investigated, using bovine and human blood circulated through the BFS model for 30 min, with a constant inflow rate of 0.76 L/min. Real-time three-dimensional flow-compensated magnetic resonance imaging (MRI), supported with Magnevist, a contrast agent improving thrombus delineation, was applied to quantify thrombus deposition and growth within the model.

Results

The study showed that the BFS model induced a flow recirculation region, which facilitated thrombosis. By 30 min, in comparison to bovine blood, human blood resulted in smaller thrombus formation, in terms of the length (13.3 ± 0.6 vs. 18.1 ± 1.3 mm), height (2.3 ± 0.1 vs. 2.6 ± 0.04 mm), surface area exposed to blood (0.67 ± 0.03 vs 1.05 ± 0.08 cm²), and volume (0.069 ± 0.004 vs. 0.093 ± 0.007 cm³), with p < 0.01. Normalization of the thrombus measurements, which excluded the flow recirculation effects, suggested that the thrombus sizes increased during the first 15 min and stabilized after 20 min. Blood properties, including viscosity, hematocrit, and platelet count affected thrombosis.

Conclusion

For the first time, contrast agent-supported real-time MRI was performed to investigate thrombus deposition and growth within a sudden expansion. This study provides experimental data for device-induced thrombosis, which is valuable for validation of computational thrombosis simulations.

中文翻译：

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用于定量血栓形成的体外实时磁共振成像。

目标

血栓形成是心血管设备失效的主要原因。虽然计算模拟是预测血栓形成和评估医疗设备风险的强大工具，但可用于验证模拟的实验数据有限。本研究的目的是为装置诱发的血栓形成提供不断增长的血栓的实验数据。

材料和方法

使用通过 BFS 模型循环 30 分钟的牛和人血以 0.76 L/min 的恒定流入速率研究后向台阶 (BFS) 内的血栓形成或突然扩张。实时 3D 流量补偿磁共振成像 (MRI) 得到 Magnevist（一种改善血栓勾画的造影剂）的支持，用于量化模型内的血栓沉积和生长。

结果

研究表明，BFS 模型诱导了流动再循环区域，从而促进了血栓形成。到 30 分钟时，与牛血相比，人血在长度（13.3 ± 0.6 对 18.1 ± 1.3 毫米）、高度（2.3 ± 0.1 对 2.6 ± 0.04 毫米）、表面积方面的血栓形成更小暴露于血液（0.67 ± 0.03 vs 1.05 ± 0.08 cm ²）和体积（0.069 ± 0.004 vs. 0.093 ± 0.007 cm ³），p  < 0.01。排除流动再循环效应的血栓测量标准化表明血栓大小在前 15 分钟内增加，并在 20 分钟后稳定。血液特性，包括粘度、血细胞比容和血小板计数影响血栓形成。

结论

首次使用造影剂支持的实时 MRI 来研究血栓在突然扩张中的沉积和生长。该研究提供了装置诱发血栓形成的实验数据，这对于验证计算血栓形成模拟很有价值。