Abstract
For coronary artery bypass grafting (CABG), free grafts such as a saphenous vein or radial artery are often used for grafts to the lateral and posterior walls. However, the relationship between top-end anastomosis design and long-term patency remains unknown. Because coronary artery blood flow is dominant during diastole, top-end anastomosis may work better if the graft is directed towards the apex, whereas the shortest graft pathway appears to be most efficient. Using computational fluid dynamic models, we evaluated the hemodynamic variables that were affected by the angle of the top-end anastomosis. We created three-dimensional geometries of the aortic root with coronary arteries that involved 75 % stenosis in the obtuse marginal and postero-lateral branches. Two bypass models under vasodilator administration were created: in a“Model A”, the top-end anastomosis is parallel to the long axis of the ascending aorta and the graft passed over the conus directed towards the apex; in a “Model B”, the top-end anastomosis is directed toward the shortest pathway, and form near the right angles to the long axis of the ascending aorta. Wall shear stress (WSS) and its fluctuation, an oscillatory shear index (OSI) were evaluated to predict fibrosis progression at the anastomosis site and graft flow. Graft flow was 197.3 ml/min and 207.3 ml/min in the “Model A” and “Model B”, respectively. The minimal WSS value inside the graft with the “Model A” and “Model B” was 0.53 Pa and 4.09 Pa, respectively, and the OSI value was 0.46 and 0.04, respectively. The top-end anastomosis of a free graft should be directed vertically towards the aorta to achieve the shortest graft pathway to maintain a high graft flow rate and to avoid the risks of endothelial fibrosis and plaque progression over the long-term after CABG.
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References
Tatoulis J (2013) Total arterial coronary revascularization—patient selection, stenoses, conduits, targets. Ann Cardiothorac Surg 2:499–506
Kasab GS, Navia JA (2006) Biomechanical consideration in the design of graft: the hemostasis hypothesis. Annu Rev Biomed Eng 8:499–535
Vural KM, Sener E, Tasdemir O (2001) Long-term patency of sequential and individual saphenous vein coronary bypass grafts. Eur J Cardiothorac Surg 19:140–144
Chatzizisis YS, Jonas M, Coskun AU, Beigel R, Stone BV, Maynard C, Gerrity RG, Daley W, Edelman ER, Feldman CL, Stone PH (2008) Prediction of the localization of high-risk coronary atherosclerotic plaques on the basis of low endothelial shear stress: an intravascular ultrasound and histopathology natural history study. Circulation 117:993–1002
Ben-Gal Y, Taggart DP, Williams MR, Orion E, Uretzky G, Shofti R, Banai S, Yosef L, Bolotin G (2013) Expandable external support device to improve Saphenous Vein Graft Patency after CABG. J Cardiothorac Surg 8:122
Peiffer V, Sherwin SJ, Weinberg PD (2013) Does low and oscillatory wall shear stress correlate spatially with early atherosclerosis? A systematic review. Cardiovasc Res 99:242–250
Krams R, Wentzel JJ, Oomen JA, Vinke R, Schuurbiers JC, de Feyter PJ, Serruys PW, Slaqer CJ (1997) Evaluation of endothelial shear stress and 3D geometry as factors determining the development of atherosclerosis and remodelling in human coronary arteries in vivo combining 3D reconstruction from angiography and IVUS (ANGUS) with computational fluid dynamics. Arterioscler Thromb Vasc Biol 17:2061–2065
John LCH (2009) Biomechanical of coronary artery and bypass graft disease: potential new approaches. Ann Thorac Surg 87:331–338
Koyama S, Itatani K, Yamamoto T, Miyazaki S, Kitamura T, Taketani T, Ono M, Kagami M (2014) Optimal bypass graft design for left anterior descending and diagonal territory in multivessel coronary disease. Interact Cardiovasc Thorac Surg 19:406–413
Nordgaard H, Swillens A, NordhangD Kierkeby I, Loo DV, Vitale N, Segers P, Haaverstad R, Lovstakken L (2010) Impact of competitive flow on wall shear stress in coronary surgery: computational fluid dynamics of a LIMA–LAD model. Cardiovasc Res 88:512–519
Nwasokwa ON (1995) Coronary artery bypass graft disease. Ann Intern Med 123:528–533
Hattler B, Messenger JC, Shroyer AL, Collins JF, Haugen SJ, Garcia JA, Baltz JH, Cleveland JC Jr, Novitzky D, Grover FL (2012) Off-Pump coronary artery bypass surgery is associated with worse arterial and saphenous vein graft patency and less effective revascularization: results from the Veterans Affairs Randomized On/Off bypass (ROOBY) trial. Circulation 125:2827–2835
Nakajima H, Kobayashi J, Tagusari O, Bando K, Niwaya K, Kitamura S (2006) Functional angiographic evaluation of individual, sequential, and composite arterial graft. Ann Thorac Surg 81:807–814
Samady H, Eshtehardi P, McDaniel MC, Suo J, Dhawan SS, Maynard C, Timmins LH, Quyyumi AA, Giddens DP (2011) Coronary artery wall shear stress is associated with progression and transformation of atherosclerotic plaque and arterial remodeling in patient with coronary artery disease. Circulation 124:779–788
Yong Xu (2014) Transcriptional regulation of endothelial dysfunction in atherosclerosis: an epigenetic perspective. J Biomed Res 28:47–52
John LC (2009) Biomechanics of coronary artery and bypass graft disease: potential new approaches. Ann Thorac Surg 87:331–338
Itatani K, Miyaji K, NakahataY Ohara K, Takamoto S, Ishii M (2011) The lower limit of the pulmonary artery index for the extracardiac Fontan circulation. J Thorac Cardiovasc Surg 142:127–135
Itatani K, Miyaji K, Tomoyasu T, Nakahata Y, Ohara K, Takamoto S, Ishii M (2009) Optimal conduit size of the extracardiac Fontan operation based on energy loss and flow stagnation. Ann ThoracSurg 88:565–573
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Koyama, S., Kitamura, T., Itatani, K. et al. Impact of top end anastomosis design on patency and flow stability in coronary artery bypass grafting. Heart Vessels 31, 643–648 (2016). https://doi.org/10.1007/s00380-015-0680-2
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DOI: https://doi.org/10.1007/s00380-015-0680-2