Computational Study on the Hemodynamics of the Bypass Shunt Directly Connecting the left Ventricle to a Coronary Artery

  • Shim Eun Bo (Department of Mechanical Engineering, Kangwon National University) ;
  • Lee Byung Jun (The Research Institute of Mechanical Technology, Pusan National University) ;
  • Ko Hyung Jong (Department of Mechanical Engineering, Kumoh National Institute of Technology)
  • Published : 2005.05.01

Abstract

A shunt from the left ventricle to the left anterior descending artery is being developed for coronary artery occlusive disease, in which the shunt or conduit connects the the left ventricle (LV) with the diseased artery directly at a point distal to the obstruction. To aid in assessing and optimizing its benefit, a computational model of the cardiovascular system was developed and used to explore various design conditions. Computational fluid dynamic analysis for the shunt hemodynamics was also done using a commercial finite element package. Simulation results indicate that in complete left anterior descending artery (LAD) occlusion, flow can be returned to approximately 65% of normal, if the conduit resistance is equal for forward and reverse flow. The net coronary flow can increase to 80% when the backflow resistance is infinite. The increases in flow rate produced by asymmetric flow resistance are enhanced considerably for a partial LAD obstruction, since the primary effect of resistance asymmetry is to prevent leakage back into the ventricle during diastole. Increased arterial compliance has little effect on net flow with a symmetric shunt, but considerably augments it when the resistance is asymmetric. The computational results suggest that an LV-LAD conduit will be beneficial when the resistance due to artery stenosis exceeds 27 PRU, if the resistance is symmetric. Fluid dynamic simulations for the shunt flow show that a recirculating region generated near the junction of the coronary artery with the bypass shunt. The secondary flow is induced at the cutting plane perpendicular to the axis direction and it is in the attenuated of coronary artery.

Keywords

References

  1. Bathe, K. J., Zhang, H., Wang, M. H., 1995, 'Finite Element Analysis of Incompressible and Compressible Fluid Flows with Free Surfaces and Structural Interactions,' Computers and Structures, 56, No. 2/3, pp. 193-213 https://doi.org/10.1016/0045-7949(95)00015-9
  2. Beyar, R., Guerci, A. D., Halperin, H. R., Tsitlik, J. E., Weisfeldt, M. L., 1989, 'Intermittent Coronary Sinus Occlusion After Coronary Arterial Ligation Results in Venous Retroperfusion,' Circ Res, Vol. 65, No. 3, pp. 695-707 https://doi.org/10.1161/01.RES.65.3.695
  3. Beyar, R., Caminker, R., Manor, D. and Sideman, S., 1993, 'Coronary Flow Patterns in Normal and Ischemic Hearts: Transmyocardial and Artery to Vein Distribution,' Ann Biomed Eng, Vol. 21, No.4, pp.435-458 https://doi.org/10.1007/BF02368635
  4. Boekstegers, P., Raake, P., Al Ghobainy, R., Horstkotte, J., Hinkel, R., Sandner, T., Wichels, R., Meisner, F., Thein, E., March, K., Boehm, D. and Reichenspurner, H., 2002, 'Stent-based Approach for Ventricle-to-coronary Artery Bypass,' Circulation, Vol. 106, No. 8, pp. 1000-1006 https://doi.org/10.1161/01.CIR.0000027106.88111.77
  5. de Zeeuw, S., Borst, C., Grundeman, P. F., 2004, 'Myocardial Blood Supply Through a Direct Left Ventricle-coronary Artery Shunt is not Aided by Augmented Coronary Capacitance,' J Thorac Cardiovasc Surg, Vol. 127, No. 6, pp.1751-1758 https://doi.org/10.1016/j.jtcvs.2003.09.039
  6. Feigl, E. O., 1989, Coronary Circulation. Textbook of Physiology. Vol. 2, 21st ed. Philadelphia, Pa: WB Saunders Co, pp. 933-950
  7. Frazier, O. H., March, R. J. and Horvath, K. A., 1999, 'Transmyocardial Revascularization with a Carbon Dioxide Laser in Patients with End-stage Coronary Artery Disease,' NEJM, 341, pp. 1021-1028 https://doi.org/10.1056/NEJM199909303411402
  8. T. Heldt, E. B. Shim, R. D. Kamm and R. G. Mark, 'Computational modeling of cardiovascular response to orthostatic stress,' Journal of Applied Physiology, vol. 92(3), pp. 1239-54, 2002 https://doi.org/10.1152/japplphysiol.00241.2001
  9. Rooz, E., Wiesner, T. F., Nerem, R. M., 1985, 'Epicardial Coronary Blood Flow Including the Presence of Stenoses and Aorto-coronary Bypasses - I : Model and Numerical Method,' J Biomech Eng, Vol. 107, No.4, pp.361-367 https://doi.org/10.1115/1.3138570
  10. Shim, E. B., Youn, C. H., Heldt, T., Kamm, R. D. and Mark, R. G., 2002, 'Computational Modeling of the Cardiovascular System After Fontan Procedure,' Lecture Notes in Computer Science, 2526, pp. 105-114
  11. Suehiro, K., Shimizu, J., Yi, G-H., Zhu, S-M., Gu, A., Sciacca, R.R., Wang, J. and Burkhoff, D., 2001, 'Direct Coronary Artery Perfusion from the Left Ventricle,' J Thorac Cardiovasc Surg, 121, pp. 307-15 https://doi.org/10.1067/mtc.2001.111968
  12. Tweden, K. S., Eales, F., Cameron, J. D., Griffin, J. C., Solien, E. E. and Knudson, M. B., 2000, 'Ventriculocoronary Artery Bypass (VCAB), a Novel Approach to Myocardial Revascularization,' Heart Forum, 3, pp. 1-8
  13. W. Schreiner, F. Neumann and W. Mohl, 'Simulation of coronary circulation with special regard to the venous bed and coronary sinus occlusion,' Journal of Biomedical Engineering, 12(5), pp. 429-43, 1990 https://doi.org/10.1016/0141-5425(90)90029-M