Dept. of Biomedical Engineering, Indiana Univ. Purdue Univ., Indianapolis, Indianapolis, IN 46202, USA.
J Appl Physiol (1985). 2011 Sep;111(3):758-65. doi: 10.1152/japplphysiol.00304.2011. Epub 2011 Jun 16.
An injection of saline solution is required for the measurement of vessel lumen area using a conductance catheter. The injection of room temperature saline to displace blood in a vessel inevitably involves mass and heat transport and electric field conductance. The objective of the present study is to understand the accuracy of conductance method based on the phenomena associated with the saline injection into a stenotic blood vessel. Computational fluid dynamics were performed to simulate flow and its relation to transport and electric field in a stenotic artery for two different sized conductance catheters (0.9 and 0.35 mm diameter) over a range of occlusions [56-84% cross-sectional area (CSA) stenosis]. The results suggest that the performance of conductance catheter is dependent on catheter size and severity of stenosis more significantly for 0.9 mm than for 0.35 mm catheter. Specifically, the time of detection of 95% of injected saline solution at the detection electrodes was shown to range from 0.67 to 3.7 s and 0.82 to 0.94 s for 0.9 mm and 0.35 mm catheter, respectively. The results also suggest that the detection electrodes of conductance catheter should be placed outside of flow recirculation region distal to the stenosis to minimize the detection time. Finally, the simulations show that the accuracy in distal CSA measurements, however, is not significantly altered by whether the position of detection electrodes is inside or outside of recirculation zone (error was within 12% regardless of detection electrodes position). The results were experimentally validated for one lesion geometry and the simulation results are within 8% of actual measurements. The simulation of conductance catheter injection method may lead to further optimization of device and method for accurate sizing of diseased coronary arteries, which has clinical relevance to percutaneous intervention.
需要使用电导导管测量血管腔面积时，需要注射生理盐水溶液。将室温生理盐水注入血管以置换血液不可避免地涉及质量和热传递以及电场电导。本研究的目的是了解基于与狭窄血管内生理盐水注射相关的现象的电导法的准确性。进行了计算流体动力学模拟，以模拟狭窄动脉中的流动及其与两种不同尺寸的电导导管（0.9 和 0.35 毫米直径）相关的传输和电场的关系，狭窄程度为[56-84% 截面积（CSA）狭窄]。结果表明，电导导管的性能取决于导管尺寸和狭窄程度，对于 0.9 毫米导管比 0.35 毫米导管更为显著。具体而言，在检测电极处检测到 95%注入的生理盐水溶液的时间范围分别为 0.67 至 3.7 秒和 0.82 至 0.94 秒，对于 0.9 毫米和 0.35 毫米导管。结果还表明，应将电导导管的检测电极放置在狭窄部位远端的回流区域之外，以最大程度地减少检测时间。最后，模拟表明，远端 CSA 测量的准确性不会因检测电极的位置在回流区内外而明显改变（无论检测电极的位置如何，误差均在 12%以内）。对一种病变几何形状进行了实验验证，模拟结果与实际测量值的误差在 8%以内。电导导管注射方法的模拟可能会进一步优化设备和方法，以实现对病变冠状动脉的准确测量，这对经皮介入具有临床意义。
