Department of Energy Resources Engineering, Egypt-Japan University of Science and Technology (E-JUST), Postal Code 21934, New Borg El-Arab City, P.O. Box 179, Alexandria, Egypt.
Mechanical Engineering Department, Faculty of Engineering, Alexandria University, Alexandria, Egypt.
Biomed Eng Online. 2021 Sep 28;20(1):95. doi: 10.1186/s12938-021-00935-y.
Coronary artery disease is an abnormal contraction of the heart supply blood vessel. It limits the oxygenated blood flow to the heart. Thus, diagnosing its severity helps physicians to select the appropriate treatment plan. Fractional flow reserve (FFR) is the most accurate method to pinpoint the stenosis severity. However, inserting the guidewire across stenosis may cause a false overestimation of severity.
To estimate the errors due to guidewire insertion, reconstructed three-dimensional coronary artery geometry from a patient-specific scan is used. A comprehensive three-dimensional blood flow model is developed. Blood is considered non-Newtonian and the flow is pulsatile. The model is numerically simulated using realistic boundary conditions.
The FFR value is calculated and compared with the actual flow ratio. Additionally, the ratio between pressure drop and distal dynamic pressure (CDP) is studied. The obtained results for each case are compared and analyzed with the case without a guidewire. It was found that placing the guidewire leads to overestimating the severity of moderate stenosis. It reduces the FFR value from 0.43 to 0.33 with a 23.26% error compared to 0.44 actual flow ratio and the CDP increases from 5.31 to 7.2 with a 35.6% error. FFR value in mild stenosis does not have a significant change due to placing the guidewire. The FFR value decreases from 0.83 to 0.82 compared to the 0.83 actual flow ratio.
Consequently, physicians should consider these errors while deciding the treatment plan.
冠状动脉疾病是一种心脏供血血管的异常收缩。它限制了含氧血液流向心脏。因此，诊断其严重程度有助于医生选择合适的治疗方案。血流储备分数（FFR）是确定狭窄严重程度的最准确方法。然而，在穿过狭窄部位插入导丝可能会导致严重程度的错误高估。
为了估计由于导丝插入引起的误差，使用从患者特定扫描重建的三维冠状动脉几何形状。开发了一个全面的三维血流模型。血液被认为是非牛顿的，并且是脉动的。该模型使用真实的边界条件进行数值模拟。
计算了 FFR 值并与实际流量比进行了比较。此外，还研究了压降与远端动压（CDP）的比值。对每个病例的获得结果与没有导丝的病例进行了比较和分析。结果发现，放置导丝会导致中度狭窄的严重程度高估。与实际的 0.44 流量比相比，FFR 值从 0.43 降低到 0.33，误差为 23.26%，而 CDP 从 5.31 增加到 7.2，误差为 35.6%。由于放置导丝，轻度狭窄的 FFR 值没有明显变化。与实际的 0.83 流量比相比，FFR 值从 0.83 降低到 0.82。
因此，医生在决定治疗方案时应考虑这些误差。
