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Simulation of LAD-LCX Bifurcation Hemodynamics of Coronary Artery Disease to Design an Effective Bypass Graft

Tajeddini Sarvestani, Farshad | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52121 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Firoozabadi, Bahar; Afshin, Hossein; Pakravan, Hossein Ali
  7. Abstract:
  8. In this study, three recent predictors of severity of coronary stenosis including fractional flow reserve (FFR), instantaneous wave free-ratio (iFR) and coronary flow reserve (CFR), are calculated for a number of patient-specific models of left coronary arteries. These patients are admitted to Tehran heart center. The main aim is presenting the optimum numerical and clinical detection technique to assess the severity of coronary stenosis. The effect of geometric features of stenosis is studied on the results of the FFR, iFR, and CFR in order to determine their accuracy. It is observed that CFR does not have a good estimate of the amount of disease. But, iFR, as a less risky test than FFR, leads to results in close agreement with the results of FFR (the gold standard test), except in the range of 0.86 ≤ iFR ≤0.93. Therefore, a hybrid algorithm including both iFR and FFR is proposed for using in hospitals as long as the CFD methods become epidemic worldwide. Next, to detect the atherosuseptible sites, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI) and relative resident time (RRT) are calculated. Also, the attempts to develop a relation between FFR, iFR and CFR (clinically measurable parameters), and maximum TAWSS (clinically unmeasurable parameter), reveal that arteries with FFR lower than its critical cut off value (0.8) are more exposed to platelets adhesion and aggregation. In the last section of this research, the efficiency of a coronary artery bypass graft (CABG) in terms of amounts of FFR, iFR, CFR and competitive flow has been investigated. This investigation illustrates some problem in this CABG which reduce its efficiency
  9. Keywords:
  10. Fractional Flow Reserve (FFR)Test ; Instantaneous Wave-free Ratio (IFR) ; Coronary Flow Reserve (CFR) ; Coronary Arteries ; Hemodynamics ; CT Angiography (CTA) ; Heart Surgery

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