Morris Liam, Fahy Paul, Stefanov Florian, Finn Ronan
Galway Medical Technologies Centre, Department of Mechanical and Industrial Engineering, Galway Mayo Institute of Technology, Galway, Ireland.
Cardiovasc Eng Technol. 2015 Dec;6(4):430-49. doi: 10.1007/s13239-015-0241-y. Epub 2015 Aug 11.
The coronary arterial tree experiences large displacements due to the contraction and expansion of the cardiac muscle and may influence coronary haemodynamics and stent placement. The accurate measurement of catheter trackability forces within physiological relevant test systems is required for optimum catheter design. The effects of cardiac motion on coronary flowrates, pressure drops, and stent delivery has not been previously experimentally assessed. A cardiac simulator was designed and manufactured which replicates physiological coronary flowrates and cardiac motion within a patient-specific geometry. A motorized delivery system delivered a commercially available coronary stent system and monitored the trackability forces along three phantom patient-specific thin walled compliant coronary vessels supported by a dynamic cardiac phantom model. Pressure drop variation is more sensitive to cardiac motion than outlet flowrates. Maximum pressure drops varied from 7 to 49 mmHg for a stenosis % area reduction of 56 to 90%. There was a strong positive linear correlation of cumulative trackability force with the cumulative curvature. The maximum trackability forces and curvature ranged from 0.24 to 0.87 N and 0.06 to 0.22 mm(-1) respectively for all three vessels. There were maximum and average percentage differences in trackability forces of (23-49%) and (1.9-5.2%) respectively when comparing a static pressure case with the inclusion of pulsatile flow and cardiac motion. Cardiac motion with pulsatile flow significantly altered (p value <0.001) the trackability forces along the delivery pathways with high local percentage variations and pressure drop measurements.
由于心肌的收缩和舒张，冠状动脉树会发生较大位移，这可能会影响冠状动脉血流动力学和支架置入。为了实现最佳的导管设计，需要在生理相关测试系统中准确测量导管的可跟踪力。此前尚未通过实验评估心脏运动对冠状动脉流速、压降和支架输送的影响。设计并制造了一种心脏模拟器，该模拟器可在特定患者的几何结构内复制生理冠状动脉流速和心脏运动。一个电动输送系统输送市售的冠状动脉支架系统，并监测沿着由动态心脏模型支撑的三个模拟患者特定薄壁顺应性冠状动脉血管的可跟踪力。压降变化对心脏运动比出口流速更敏感。对于狭窄面积减少56%至90%的情况，最大压降从7 mmHg变化到49 mmHg。累积可跟踪力与累积曲率之间存在很强的正线性相关性。所有三根血管的最大可跟踪力和曲率分别为0.24至0.87 N和0.06至0.22 mm-1。将静态压力情况与包含脉动流和心脏运动的情况进行比较时，可跟踪力的最大和平均百分比差异分别为(23-49%)和(1.9-5.2%)。伴有脉动流的心脏运动显著改变了（p值<0.001）沿输送路径的可跟踪力，局部百分比变化和压降测量值都很高。
