Influence of Intracoronary Shunt Size on Coronary Endothelial Function during Off-Pump Coronary Artery Bypass

  • Roland G. Demaria
  • Simon Fortier
  • Olivier Malo
  • Michel Carrier
  • Louis P. Perrault


Objective: The insertion of intracoronary shunts during off-pump coronary artery bypass surgery may induce severe endothelial dysfunction in the target arteries. The purpose of this study was to determine the role of the ratio of the shunt diameter to the target artery diameter in the development of endothelial dysfunction and to develop guidelines for selecting the most appropriate shunt size.

Methods: Nine swine (25 ± 4 kg) were used for this study. Three ClearView shunts 3 mm, 2 mm, and 1.25 mm in diameter were inserted proximally to distally via 3 arteriotomies into the right coronary artery to obtain oversizing with the 3-mm shunt, undersizing with the 1.25-mm shunt, and a satisfying congruence with the 2-mm shunt. The shunts were left in place for 15 minutes, and the levels of bleeding were quantified. Coronary rings upstream and downstream from the arteriotomies were then harvested and placed in organ chambers to study endothelium-dependent relaxations to serotonin and bradykinin. Noninstrumented coronary arteries served as controls.

Results: A decrease of endothelium-dependent relaxation occurred with the 3-mm shunts (P < .005), which were associated with an adequate hemostasis. A decrease of endothelium-dependent relaxation occurred with the 2-mm shunts (P < .05), which were associated with intermittent bleeding, and no significant decrease of endothelium-dependent relaxation occurred with 1.25-mm shunts (P > .05), which were associated with continuous bleeding.

Conclusions: Intracoronary shunts are associated with different disadvantages, depending on the mismatch to the target coronary artery, and whatever their size, shunts are not the ideal device for safely obtaining a satisfactory hemostasis. These results support our clinical attitude of the selective use of intracoronary shunts.


Fonger JD, Yang XM, Cohen RA, Haudenschild CC, Shemin RJ. 1992. Impaired relaxation of the human mammary artery after temporary clamping. J Thorac Cardiovasc Surg 104:966-71.\nFranzone AJ, Wallsh ES, Stertzer H, DePasquale NP, Bruno MS. 1977. Reduced incidence of intraoperative myocardial infarction during coronary bypass surgery with use of intracoronary shunt technique. Am J Cardiol 39:1017-20.\nGundry SR, Romano MA, Shattuck OH, Razzouk AJ, Bailey LL. 1998. Seven-year follow-up of coronary artery bypasses performed with and without cardiopulmonary bypass. J Thorac Cardiovasc Surg 115:1273-7.\nHangler HB, Pfaller K, Antretter H, Dapunt OE, Bonatti JO. 2001. Coronary endothelial injury after local occlusion on the human beating heart. Ann Thorac Surg 71:122-7.\nIp JH, Fuster V, Badimon L, Badimon J, Taubman MB, Chesebro JH. 1990. Syndromes of accelerated atherosclerosis: role of vascular injury and smooth muscle cell proliferation. J Am Coll Cardiol 15:1667-87.\nJaggy C, Lachat M, Leskosek B, Kunz M, Zund G, Turina M. 1999. Flow measurements through aortocoronary and intraluminal coronary shunts. Swiss Surg 5:228-32.\nLevinson MM, Fooks GS. 1995. Coronary grafting using a temporary intraluminal shunt instead of heart-lung bypass. Ann Thorac Surg 60:1800-1.\nLucchetti V, Capasso F, Caputo M, et al. 1999. Intracoronary shunt prevents left ventricular function impairment during beating heart coronary revascularization. Eur J Cardiothorac Surg 15:255-9.\nMariani MA, Gu YJ, Boonstra PW, Grandjean JG, van Oeveren W, Ebels T. 1999. Procoagulant activity after off-pump coronary operation: is the current anticoagulation adequate? Ann Thorac Surg 67:1370-5.\nOkazaki Y, Takarabe K, Murayama J-I, et al. 2001. Coronary endothelial damage during off-pump CABG related to coronary-clamping and gas insufflation. Eur J Cardiothorac Surg 19:834-9.\nPerrault LP, Desjardins N, Nickner C, Geoffroy P, Tanguay JF, Carrier M. 2000. Effects of occlusion devices for minimally invasive coronary artery bypass surgery on coronary endothelial function of atherosclerotic arteries. Heart Surg Forum 3:287-92.\nPerrault LP, Menasché P, Bidouard JP, et al. 1997. Snaring of the target vessels in less invasive bypass operations does not cause endothelial dysfunction. Ann Thorac Surg 63:751-5.\nArai H, Yochida T, Izumi H, Sunamori M. 2000. External shunt for off-pump coronary artery bypass grafting: distal coronary perfusion catheter. Ann Thorac Surg 70:681-2.\nAscione R, Lloyd CT, Underwood MJ, Lotto AA, Pitsis AA, Angelini GD. 1999. Economic outcome of off-pump coronary artery bypass surgery: a prospective randomized study. Ann Thorac Surg 68:2237-42.\nBoulanger CM, Vanhoutte PM. 1997. G proteins and endothelium-dependent relaxations. J Vasc Res 34:175-85.\nChavanon O, Perrault LP, Menasché P, Carrier M, Vanhoutte PM. 1999. Endothelial effects of hemostatic devices for continuous cardioplegia or minimally invasive operations: updated in 1999. Ann Thorac Surg 68:1118-20.\nDapunt OE, Raji MR, Jeschkeit S, et al. 1999. Intracoronary shunt insertion prevents myocardial stunning in a juvenile porcine MIDCAB model absent of coronary artery disease. Eur J Cardiothorac Surg 15:173-9.\nDemaria RG, Fortier S, Carrier M, Perrault LP. 2001. Early multifocal stenosis after coronary artery snaring during off-pump coronary artery bypass in a patient with diabetes. J Thorac Cardiovasc Surg 122:1044-5.\nPfister AJ. 1997. The safety of CABG without cardiopulmonary bypass. Ann Thorac Surg 64:590-1. Ricci M, Karamanoukian HL, D'Ancona G, et al. 2000. Survey of resident training in beating heart operations. Ann Thorac Surg 70:479-82.\nRobison RJ, Brown JW, Deschner WP, King RD. 1986. Intraluminal shunting of operatively severed aortocoronary saphenous vein grafts. Ann Thorac Surg 42:475-6.\nShimokawa H, Aarhus LL, Vanhoutte PM. 1987. Porcine coronary arteries with regenerated endothelium have a reduced endothelium-dependent responsiveness to aggregating platelets and serotonin. Circ Res 61:256-70.\nTrapp VG, Bisarya R. 1975. Placement of coronary artery bypass graft without pump oxygenator. Ann Thorac Surg 19:1-9. Vanhoutte PM, Shimokawa H. 1989. Endothelium-derived relaxing factor and coronary vasospasm. Circulation 80:1-9.\n
How to Cite
Demaria, R. G., Fortier, S., Malo, O., Carrier, M., & Perrault, L. P. (2005). Influence of Intracoronary Shunt Size on Coronary Endothelial Function during Off-Pump Coronary Artery Bypass. The Heart Surgery Forum, 6(3), 160-168.

Most read articles by the same author(s)