Asian Cardiovasc Thorac Ann 2006;14:164-165
© 2006 Asia Publishing EXchange Ltd
Anastomosis of Small Arteries: Implications for Coronary Artery Grafts in Asians
Reida M El Oakley, FRCS,
Chuen Neng Lee, FRCS,
Oon Cheong Ooi, AFRCS
Department of Cardiac, Thoracic and Vascular Surgery, The Heart Institute, National Healthcare Group, Singapore
For reprint information contact: Reida M El Oakley, MD Tel: 966 5 5160 9140 Fax: 966 1 4653 0105 Email: surrmo{at}nus.edu.sg, Heart Centre, King Fahd Medical City, PO Box 59046, Riyadh 11525, Kingdom of Saudi Arabia.
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ABSTRACT
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The internal mammary artery (IMA) in patients with small body surface area, frequently found in the Asian population, is often small and delicate and can be easily damaged during suturing, particularly at the "toe" of the anastomosis. This may lead to less frequent utilization of the IMA as a bypass conduit. We describe a technique for anastomosing a small-caliber IMA to a coronary artery, using the tip of the graft as an autologous buttress to reinforce the toe of the anastomosis.
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INTRODUCTION
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The internal mammary artery (IMA) has been shown to be superior to other conduits for coronary artery bypass grafting, in terms of patency rate, symptomatic relief, as well as early and late survival.1–4 However, in certain patients with a small body surface area, the IMA is often small and delicate and it can be easily damaged during suturing, particularly at the distal angle (toe) of the anastomosis. This may partly account for the reluctance of some surgeons to use the IMA as a conduit in patients with small-caliber vessels, frequently found in the Asian population, as the anastomosis is technically more difficult to perform.5 A small IMA tends to be thin walled and lacerates easily if the suture is pulled to secure hemostasis, or even inadvertently. We describe an alternative technique for performing this anastomosis, taking advantage of the redundant part of the tip of the internal mammary artery as an autologous buttress to reinforce the anastomosis.
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TECHNIQUE
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The pedicled IMA is mounted with the pleural surface towards the surgeon on the ipsilateral hemisternum, using two fine artery forceps. It is then bevelled and incised longitudinally. The arteriotomy is extended using 135° coronary Pott’s scissors. The arteriotomy should be 2.5 to 3 times the diameter of the coronary artery. The distal tip of the IMA is checked to ensure that the longitudinal incision is longer than the arteriotomy on the coronary artery. Using a double-arm 7/0 Pronova suture (Johnson & Johnson, Newark, NJ, USA), the first stitch is placed through the IMA to the left of the heel from outside to inside. The same needle is passed through the coronary artery at the corresponding position from inside to outside, and returned from outside into the lumen of the IMA. To avoid direct suturing through the heel of the anastomosis, which carries the risk of catching the back wall of the IMA, especially in small arteries, we recommend straddling the heel by inserting a stitch on either side of the heel of the anastomosis. The suturing is continued beyond the heel of the graft.
At this point, the IMA is parachuted down to the coronary artery and the suturing is continued. Two bites before the toe of the anastomosis is approached, the tip of the IMA is trimmed to an inverted V-shape to fit the length of the arteriotomy incision (Figure 1
). The tip of the V-incision is left attached to allow indirect handling of the IMA toe, using the redundant part (Figure 1). The section of IMA distal to the trimming is folded backwards onto the new tip of the IMA (Figures 1 and 2). The needle is inserted through the redundant part of the IMA from the endothelial surface to the adventitial surface, and through a point just before the tip of the IMA from the adventitial surface to the endothelial surface. The same needle is passed through the coronary artery at the corresponding point from within the lumen (Figure 2). This technique of incorporating the redundant part of the tip of the IMA in the suturing is carried out just before the toe, at the toe, and just beyond the toe stitch. Thereafter, routine suturing is performed to complete the anastomosis.
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Figure 1. The tip of the internal mammary artery (IMA) is trimmed to an inverted V-shape to fit the length of the arteriotomy incision. A needle is inserted through the redundant part of the IMA from the endothelial surface to the adventitial surface, and then through a point just before the tip of the IMA from the adventitial surface to the endothelial surface. The same needle is passed through the coronary artery at the corresponding point from within the lumen.
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Figure 2. The process described in Figure 1 is performed at and beyond the point of the toe of the anastomosis.
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DISCUSSION
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This technique has been employed in more than 500 coronary artery bypass graft cases over the past 4 years, with less than 1% operative mortality in patients who had isolated elective CABG. We have yet to encounter any laceration of the IMA toe. However, there has been one case of bleeding from a small laceration on the left anterior descending artery close to the IMA-to-left anterior descending artery anastomosis, requiring revision of the anastomosis, and one case of recurrence of angina at 3 months after surgical revascularization, with coronary angiography demonstrating anastomotic narrowing requiring angioplasty. The technique may also be used for other small arterial conduits or during anastomosis of free arterial grafts to the aorta.
We suggest that this technique, which takes advantage of the redundant part of the tip of the IMA as an autologous buttress to reinforce the anastomosis, may be useful in reducing the incidence of bleeding from the toe of the IMA-to-coronary anastomosis, without compromising the early outcome of elective isolated CABG.
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REFERENCES
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- Dignan RJ, Yeh T Jr, Dyke CM, Lutz HA 3rd, Wechsler AS. The influence of age and sex on human internal mammary artery size and reactivity. Ann Thorac Surg 1992;53:792–7.[Abstract]
- Loop FD, Lytle BW, Cosgrove DM, Stewart RW, Goormastic M, Williams GW, et al. Influence of the internal-mammary-artery graft on 10-year survival and other cardiac events. N Engl J Med 1986;314:1–6.[Abstract]
- Cameron AA, Green GE, Brogno DA, Thornton J. Internal thoracic artery grafts: 20-year clinical follow-up. J Am Coll Cardiol 1995;25:188–92.[Abstract]
- Edwards FH, Clark RE, Schwartz M. Impact of internal mammary artery conduits on operative mortality in coronary revascularization. Ann Thorac Surg 1994;57:27–32.[Abstract]
- Goldsmith I, Lip GY, Tsang G, Patel RL. Comparison of primary coronary artery bypass surgery in a British Indo-Asian and white Caucasian population. Eur Heart J 1999;20:1094–100.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
