Ann Thorac Surg 2004;78:2033-2036
© 2004 The Society of Thoracic Surgeons
Original Article: Cardiovascular
Early and Mid-Term Outcome of Anastomosis of Gastroepiploic Artery to Left Coronary Artery
Kenji Takahashi, MD*,
Kazuyuki Daitoku, MD,
Sei Nakata, MD,
Shigeru Oikawa, MD,
Masahito Minakawa, MD,
Norihiro Kondo, MD
Department of Cardiovascular Surgery, Aomori Rousai Hospital, Hachinohe, Japan
Accepted for publication June 2, 2004.
* Address reprint requests to Dr Takahashi, Department of Cardiovascular Surgery, Aomori Municipal Hospital, Katta 1–14–20, Aomori 030–0821, Japan (E-mail: takaken{at}r66.7-dj.com).
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Abstract
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BACKGROUND: The performance of a bypass made to the left coronary artery using the gastroepiploic artery was examined.
METHODS: Sixty-nine cases of bypass operation in which the gastroepiploic artery had been anastomosed to the left coronary artery at least 3 years prior were examined. All cases were performed by the same surgeon during the period from April 1989 to April 2000. Performance immediately after the operation and performance at least 3 years after the operation were examined on the basis of graft patency rate.
RESULTS: Graft patency rates in cases with an anastomosis to the left anterior descending coronary artery and cases with an anastomosis to the circumflex artery were favorable immediately after the operation, at 96.0% (24 of 25) and 100% (18 of 18), respectively. However, over the mid-term, the patency rate dropped to 58.8% (10 of 17) in cases with an anastomosis to the left anterior descending artery, and two cases of cardiogenic sudden deaths occurred during the course of follow-up. The graft patency rate in cases with an anastomosis to the circumflex artery, on the other hand, remained favorable, at 93.3% (14 of 15). In a sequential bypass grafting through the right coronary artery, the graft between the left anterior descending coronary artery and the right coronary artery was closed, and the graft patency rate between the right coronary artery and the circumflex artery was 71.4% (10 of 14).
CONCLUSIONS: The mid-term patency rate was poor for cases in which the gastroepiploic artery had been anastomosed to the left anterior descending coronary artery, which suggests that the procedure should be avoided. On the other hand, the patency rate was relatively favorable when the gastroepiploic artery had been anastomosed to the circumflex artery.
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Introduction
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In coronary artery bypass grafting (CABG), the left gastroepiploic artery (GEA) is an important graft for multivessel bypass cases in which the artery is frequently used as an arterial graft. However, most reports are on the right coronary artery (RCA); there are only a few reports on the mid-term outcome of the left coronary artery [1–3]. The early and mid-term outcome of GEA grafted to the left coronary artery is herein reported, along with the problems involved.
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Material and Methods
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Sixty-nine cases of bypass operation in which the GEA had been anastomosed to the left coronary artery were examined. All patients underwent CABG at least 3 years prior by the same surgeon during the period from April 1989 to April 2000. The male-to-female ratio was 58 to 11, and the age at the time of operation ranged from 37 to 78 years (mean, 60.4 years). As for the number of grafts, there were 7 cases of one-vessel bypass, 17 cases of two-vessel bypass, 19 cases of three-vessel bypass, 19 cases of four-vessel bypass, 6 cases of five-vessel bypass, and 1 case of six-vessel bypass. The artery was grafted to the left anterior descending artery (LAD) in all 7 cases of one-vessel bypass, which included 1 case in which the left internal thoracic artery (LITA) could not be used owing to radiotherapy for thymoma, 1 case of LITA injury, 1 case of GEA-free aortocoronary bypass grafting between the ascending artery and the LAD, and 4 cases of reoperation. The breakdown of GEA anastomosis was as follows: 17 cases of GEA-LAD, 8 cases of GEA-LAD-diagonal branch (Dx), 3 cases of GEA-RCA-LAD, 14 cases of GEA-circumflex artery (Cx), 4 cases of GEA-Cx-Cx, and 23 cases GEA-RCA-Cx. At our institution, we use arterial grafts whenever possible. Of the 158 grafts used in this study, 154 were arterial grafts and 4 were venous grafts.
Surgeries were performed using normal temperature on-pump CABG with cardioplegic arrest in 50 cases, on-pump CABG on a beating heart in 8 cases, and off-pump CABG on a beating heart in 11 cases. There were 5 cases of reoperation. The GEA was resected using the pedicle, and led across the anterior surface of the liver through a small hole made in the central tendon of the diaphragm, into the pericardium. The artery was then grafted to the coronary artery by interrupted suture using 7-0 polypropylene thread. As for the criteria for grafting the GEA to the LAD, the effects of competition with the native flow were taken into consideration, and the indication was narrowed to include the presence of stenosis of 90% or greater on the central side of the prospective anastomotic site in the coronary artery, or of 75% stenosis at two or more locations, and a diameter of 1.5 mm or greater of the target coronary artery and the peripheral end of the GEA. In particular, sequential bypass grafting was performed only in cases with a sufficient GEA diameter, which was defined as a diameter of at least 1.5 mm at the peripheral anastomotic site, and anastomosis was performed at the central end first. For the Cx, the subjects were limited to cases with stenosis of 75% or greater on the central side of the prospective anastomotic site, and in which anastomosis was possible. Sequential bypass for the LAD and the Cx through the RCA was performed in cases with severe stenosis of at least 90% on the central side of the prospective anastomotic site in the RCA. In all cases, the continuous administration of diltiazem was performed at 1 to 3 µg/kg/min from the time the anastomosis was completed for the prevention of postoperative graft spasms, and treatment was switched to oral administration of a calcium antagonist for 2 months or longer from the time oral intake became possible.
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Results
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There was no fatality as a result of surgery. However, sudden deaths occurred during a bowel movement in 2 of 23 patients who underwent GEA-RCA-Cx grafting on postoperative days 10 and 12. In addition, there were 3 patients who required systemic management because of ST elevation that may be attributed to spasms in the graft shortly after surgery. After a long period after surgery, sudden deaths that seemed to have been cardiac deaths occurred in two GEA-LAD cases (11.8%). As for the graft patency immediately after surgery, grafts were patent between the GEA-LAD and the LAD-Dx in all cases of GEA-LAD and GEA-LAD-Dx grafting, and between the GEA-RCA in all cases of GEA-RCA-LAD grafting, but patency was poor between the RCA-LAD. As for GEA-Cx and GEA-Cx-Cx, the GEA was patent in all cases, but the patency rate for the Cx-Cx was 75%. In cases of GEA-RCA-Cx grafting, grafts were patent between the GEA-RCA in all cases, but the patency rate for the RCA-Cx was 80.9%.
Graft patency rates were examined in patients who had been operated on at least 3 years prior (from 3 years 2 months to 12 years 6 months since surgery; mean, 6 years 10 months). Angiography of the graft was performed in 49 cases. In cases of GEA-LAD-(Dx) grafting, the patency rate at the GEA-LAD was 52.9%, showing a marked decrease. The patency rate for single anastomosis at the GEA-Cx was favorable. In cases of GEA-Cx-Cx grafting, the GEA-Cx was patent in all cases, and the patency rate for the Cx-Cx was 66.7%. In GEA-RCA-Cx cases, the patency rates were 87.5% for the GEA-RCA and 71.4% for the RCA-Cx. Incidentally, the patency rates immediately after surgery for cases that received a GEA-RCA single bypass during the same period and the patency rates at least 3 years after surgery were favorable (Table 1).
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Comment
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When the use of the GEA in CABG was started by Suma and associates [1] and Albertini and colleagues [2], the location of use was primarily in the region of the RCA. Since then, use in the LAD region and the Cx region has been noted from time to time in a few cases [3–8]. At one point at our institution, the graft was being actively used not only as the RCA but also as the LAD and Cx, owing to the favorable patency of the arterial graft. In the present study, the grafting methods were examined from the perspective of the graft patency rates in patients who had been operated on at least 3 years previously [7]. Although postoperative angiography of the graft to the LAD (GEA-LAD-(Dx)) revealed favorable graft patency rates, the long-term performance dropped to 58.9%, and there were two cases of sudden deaths likely caused by cardiac death during the course of follow-up. An anastomosis that was patent over the long term was found only in patients with complete occlusion of the coronary artery on the proximal side of the anastomotic site during angiography. As such, the patency rate for GEA-LAD-(Dx) is favorable immediately after surgery, but decreases in the mid-term (Fig 1). This may be attributed to the need for a long graft to allow the GEA to reach the LAD. In addition, occlusion for an extended period may have been caused by anastomosis at locations at which the graft diameter might be insufficient, which leads to inadequate blood pooling and insufficient blood supply even during the diastolic phase of the heart when the vascular resistance decreases. This causes competition with what little blood flow there might be from the coronary artery even when there is a severe stenosis on the proximal side of the anastomotic site at the LAD, leading to a tapering phenomenon. In addition, the fact that the GEA is grafted to the coronary artery in a retrograde fashion may have also contributed to the poor patency rate. Therefore, it seemed that the grafting method that uses the GEA for the left anterior descending artery region should be avoided on the basis of the poor patency rate of the graft during the long term and the high risk of sudden death caused by graft occlusion. On the contrary, the graft patency rate for the GEA-Cx grafting method, which does not require a long graft, was relatively satisfactory.
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Fig 1. Patent gastroepiploic artery (GEA) in sequential bypass anastomosed to the left anterior descending coronary artery (LAD) and first diagonal artery (D1) 10 years after operation.
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Next, we examined sequential bypass cases in which grafting to the left coronary artery was performed through the RCA. Although postoperative angiography showed a 100% patency rate for the GEA-RCA, the rate of patency between the anastomotic branches was 33.3% for the RCA-LAD, which was lower than the 80.9% patency rate for the RCA-Cx (Fig 2). In addition, from the perspective of mid-term performance, the patency rate for the GEA-RCA was 87.5%, the RCA-LAD was occluded, and the patency rate for the RCA-Cx was 71.4%. The poor patency rate for the RCA-LAD may be explained as follows. Because the right ventricular pressure is low during the systolic phase, even when there is a severe stenosis of at least 90% on the proximal side of the RCA, the vascular resistance in the right coronary artery is low, and blood within the GEA flows smoothly into the RCA during the systolic phase. However, because the vascular resistance in the LAD is large during this phase, blood from the GEA does not flow into the LAD, but is rather consumed by the right coronary artery, and blood pooling in the GEA becomes depleted when the vascular resistance of the LAD drops during the diastolic phase of the left ventricle. Because an effective blood volume cannot be provided to the LAD, the graft will most likely become smaller in diameter with time, until it finally closes. On the other hand, however, the rate of graft patency between the RCA and the Cx in a sequential bypass was favorable compared with that of the LAD. The fact that the distance between the RCA and the Cx was short and that adequate blood flow was obtained owing to the fact that the artery was grafted to the Cx, where the diameter was sufficient, may have been significant contributing factors.
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Fig 2. Patent gastroepiploic artery (GEA) in sequential bypass anastomosed to the right coronary artery (RCA) and circumflex artery (Cx) 8 years after operation.
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Because the GEA is a muscular artery with thick smooth muscles, it is generally considered to be a graft in which spasms can easily occur [9–12]. When sequential bypass grafting to the RCA and the Cx is performed, a wide area of the myocardium becomes dependent on the blood flow from the GEA graft. Therefore, once spasms occur in the GEA, ischemia may occur in a wide area of the myocardium, greatly affecting the hemodynamics and at times resulting in death. Particularly immediately after surgery, factors such as mechanical stimulation when the GEA is resected, the effects of the drugs that were used, and blood-gas abnormalities create an environment in which spasms can easily occur. Although it is therefore important to take adequate precautions against spasms during postoperative management, spasms may still occur at times despite such efforts. Spasms may also occur not only immediately after surgery, but 1 to 2 weeks after surgery. We have experienced three cases in which spasms suddenly occurred in the GEA graft within weeks after surgery, causing ST changes and aggravating the hemodynamics. In addition to these cases, spasm was also the likely cause for sudden death in two cases. In both cases, the incident occurred during a bowel movement in the evening, suggesting that mechanical stimulation of the graft and stimulation of the vagal nerve induced by elevated abdominal pressure may have induced spasms in the GEA, causing ventricular fibrillation that led to sudden death. Therefore, adequate precautions must be taken to prevent spasms after surgery when the bypass grafting method is used that requires the GEA to supply blood to a wide area of the myocardium.
As for the single grafting of the GEA to the RCA, favorable patency rates can be expected in cases with severe stenosis on the central side of the RCA. However, examination of cases in which the graft had been used as the left coronary artery has revealed that, although long-term patency rates for grafting to the Cx are relatively favorable, long-term patency rates are low for grafting to the LAD. They have also revealed that the use of this method should be avoided owing to the risk of sudden death caused by graft occlusion during follow-up.
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References
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- Suma H, Isomura T, Horii T, et al. Late angiographic result of using the gastroepiploic artery as a graft Thorac Cardiovasc Surg 2000;120;:496-498.
- Albertini A, Lochegnies A, Khoury GE, et al. Use of the right gastroepiploic artery as a coronary artery bypass in 307 patients Cardiovasc Surg 1998;6:419-423.[Medline]
- Voutilainen S, Verkkala K, Jarvinen A, et al. Angiographic 5-year follow-up study of right gastroepiploic artery grafts Ann Thorac Surg 1996;62:501-505.[Abstract/Free Full Text]
- Suma H, Fukumoto H, Takeuchi A. Coronary artery bypass grafting by utilizing in situ right gastroepiploic artery: basic study and clinical application Ann Thorac Surg 1987;44:394-397.[Abstract/Free Full Text]
- Pym J, Brown PM, Charrette EJ, et al. Gastroepiploic-coronary anastomosisA viable alternative bypass graft. J Thorac Cardiovasc Surg 1987;94:256-259.[Abstract]
- Suma H, Amano A, Fukuda S, et al. Gastroepiploic artery graft for anterior descending coronary artery bypass Ann Thorac Surg 1994;57:925-927.[Abstract/Free Full Text]
- Takahashi K, Nagao K, Odagiri S, et al. The potential of anastomosis of the gastroepiploic artery to the left anterior descending artery in coronary artery bypass grafting J Jpn Assoc Thorac Surg 1995;43:1706-1709.
- Mills NL, Hockmuth DR, Everson CT, et al. Right gastroepiploic artery used for coronary artery bypass grafting J Thorac Cardiovasc Surg 1993;106:579-586.[Abstract]
- Buikeama H, Grandjean J, Broek VD, et al. Differences in vasomotor control between gastroepiploic and left internal artery Circulation 1992;86(Suppl 2):II-205-9.[Medline]
- Yang Z, Siebenmann R, Studer M, et al. Similar endothelium-dependent relaxation, but enhanced contractility, of the right gastroepiploic artery as compared with the internal mammary artery J Thorac Cardiovasc Surg 1993;104:459-464.
- Ochiai M, Ohno M, Taguchi J, et al. Responses of human gastroepiploic arteries to vasoactive substances: comparison with responses of internal mammary arteries and saphenous veins J Thorac Cardiovasc Surg 1992;104:453-458.[Abstract]
- Hanet C, Semaan C, Khoury G, et al. Differences of vasoreactivity between gastroepiploic artery grafts late after bypass surgery and grafted coronary arteries Circulation 1994;90:155-159.
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Abstract
Introduction
