Asian Cardiovasc Thorac Ann 2005;13:357-360
© 2005 Asia Publishing EXchange Ltd
All Internal Thoracic Artery Composite Graft Revascularization
Hiroshi Izumoto, MD,
Kazuaki Ishihara, MD,
Tetsunori Kawase, MD,
Takayuki Nakajima, MD,
Hiroshi Satoh, MD,
Kohei Kawazoe, MD
Department of Cardiovascular Surgery, Iwate Medical University Memorial Heart Center, Iwate, Japan
For reprint information contact: Hiroshi Izumoto, MD Tel: 81 19 651 5111 Fax: 81 19 624 8374 Email: h_izumoto{at}imu.ncvc.go.jp, Department of Cardiovascular Surgery, Iwate Medical University Memorial Heart Center, 1-2-1, Chuodori, Morioka, Iwate 020-8505, Japan.
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ABSTRACT
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The aim of this study was to determine the most efficient design of composite grafts and clarify the technical feasibility rate of composite grafting using internal thoracic artery exclusively in patients undergoing triple-vessel revascularization. Retrospective analysis of 104 consecutive patients was carried out. An in situ left internal thoracic artery graft for the left anterior descending artery area, with attachment of the right internal thoracic artery to the side of the left internal thoracic artery to revascularize the circumflex and right coronary vessels, was the most efficient graft design. The technical feasibility rate was 80% (83/104 patients). The mean number of distal anastomoses for the entire group was 3.8 ± 0.8 per patient. Intraoperative left internal thoracic artery flow rate was 91.6 ± 37.8 mL·min–1. With more experience, it is thought that the technical feasibility rate could be increased.
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INTRODUCTION
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Tector and colleagues1 reported good long-term results of coronary bypass grafting (CABG) using an aggressive approach and the exclusive use of internal thoracic artery (ITA) conduits as composite grafts to treat patients with triple-vessel disease. There is increasing interest in completely arterial revascularization.2–3 However, revascularization exclusively with ITA is an extreme approach, although the idea is appealing. One of the concerns with this method is the limited length of the ITA. Therefore, the design of the composite graft may be important in successful CABG. The graft design and technical feasibility rate in patients with triple-vessel disease or its equivalent have not been investigated in detail. To better understand the practical indications for, and limitations of this approach, we sought to clarify ITA graft design and the technical feasibility rate in this retrospective study.
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PATIENTS AND METHODS
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We started using a totally ITA revascularization approach with a composite graft in January 2000. From January 2000 through April 2003, 104 patients with triple-vessel disease or its equivalent were scheduled for CABG using only ITA grafts. This was a consecutive series and patients were not excluded because of poor left ventricular function, female sex, older age, diffuse disease, or increased operative risk; totally ITA composite graft revascularization was attempted in all 104 patients. Most ITA grafts were harvested as in situ skeletonized grafts using electrocautery or an ultrasonic scalpel, based on the surgeon’s preference. In certain situations, ITA grafts were harvested as pedicled grafts and were skeletonized before use. Intraluminal infusion of drugs was not performed, although papaverine or olprinone hydrochloride-soaked sponges were used to wrap the grafts until anastomosis.4 It was unusual for ITA grafts to be damaged during harvesting. If damage occurred, every effort was made to repair the graft. The composite graft was constructed before initiating cardiopulmonary bypass. All distal anastomoses were performed under cardiopulmonary bypass, aortic crossclamping, and cardioplegic arrest in patients undergoing conventional CABG. Parallel or diamond-shaped anastomoses were made, but parallel anastomosis was preferred if graft length allowed. At the end of the procedure, blood flow in the main left ITA was measured with a 2.0 or 3.0 mm transit time Doppler flow probe (Medi-Stim AS, Oslo, Norway), and the data were recorded. No special pharmacological therapy was used perioperatively in this study group. However, when a radial artery graft had to be used, intravenous diltiazem was routinely administered. The composite graft design was classified and the technical feasibility rate of ITA composite graft revascularization was determined, as well as the causes of failure.
The patients comprised 87 men and 17 women, with a mean age of 67.2 ± 9.5 years (range, 37–82 years). The mean preoperative left ventricular ejection fraction was 51.2% ± 14.1% with a range of 12% to 81%. Figure 1
shows the preoperative patient profile. Thirty-one patients (29%) had unstable angina, and 13 (12.5%) received intra-aortic balloon pump support. One patient (1%) had single-vessel disease, 9 (9%) had double-vessel disease, 94 (90%) had triple-vessel disease, and 14 (13%) had left main coronary artery disease. Patients with single- or double-vessel disease had concomitant left main artery disease. Prior to hospital discharge, most patients (96) underwent stress thallium scintigraphy to evaluate residual ischemic changes, and left ITA blood flow was confirmed with transthoracic Doppler echocardiography in 98 patients. All data are reported as mean ± standard deviation.
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Figure 1. Clinical profile of patients. DM = diabetes mellitus, OCI = old cerebral infarction, CRF = chronic renal failure, HT = hypertension, Ao Dis = disease in ascending aorta.
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RESULTS
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Sixteen patients underwent off-pump CABG and one patient in the off-pump group was converted to on-pump CABG because of hemodynamic instability. Two patients underwent on-pump beating heart CABG, and 85 had conventional CABG. The mean crossclamp time for the conventional CABG patients was 73.9 ± 26.7 min (range, 41 to 176 min).
Figure 2 illustrates the ITA composite graft design. In 82 patients (group A), an in situ left ITA segment was used to revascularize the left anterior descending artery (LAD), and a branched right ITA segment was used for the circumflex artery and right coronary artery (RCA) area. In one patient (group B), the left ITA was used to revascularize the LAD, and the branched right ITA was used for the circumflex artery. A small segment of the right ITA was used to revascularize the RCA as a coronary-coronary bypass. The remaining 21 patients were in the technical failure group (group C). In 19 of these patients, the left ITA was used to revascularize the LAD. A right ITA segment was attached to the side of the in situ left ITA segment and used to revascularize the circumflex artery. A saphenous vein or radial artery graft was used as a free graft for the RCA. In one patient, the left ITA was used to revascularize the LAD, a branched right ITA segment was used to revascularize the circumflex artery, and a free radial artery graft was attached to the in situ right ITA and used to revascularize the RCA. In one patient, the left ITA was used to revascularize the LAD and the branched right ITA was used to revascularize the circumflex artery. A segment of the saphenous vein graft was attached to the side of the right ITA and used to revascularize the RCA. Therefore, we failed to achieve all-ITA composite graft revascularization in group C.
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Figure 2. Schematic presentation of graft design. C-C bypass = coronary-coronary bypass, LAD = left anterior descending artery, LITA = left internal thoracic artery, PL = posterolateral circumflex artery, RA = radial artery, RCA = right coronary artery, RITA = right internal thoracic artery, SVG = saphenous vein graft.
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The overall feasibility rate of totally ITA composite graft revascularization was 80% (83/104 patients). The causes of failure were both simple and complex: poor quality of the ITA in 3 patients, large heart in 8, lack of experience (inappropriately short right ITA harvest or inappropriate graft design) in 10 cases, ITA injury in 1, and distal coronary disease in 2. The mean number of distal anastomoses for the entire group was 3.8 ± 0.8 per patient; there were 1.4 ± 0.5 (range, 1–2) distal anastomoses per patient with the left ITA segment and 2.2 ± 0.6 (range, 1–4) per patient with the right ITA segment. In the 83 patients in the successful groups (groups A and B), the mean number of distal anastomoses was 3.8 ± 0.8; there were 1.5 ± 0.5 (range, 1–2) distal anastomoses per patient with the left ITA segment and 2.3 ± 0.5 (range, 2–4) per patient with the right ITA segment.
Intraoperative left ITA flow was 91.6 ± 37.8 mL·min–1 (range, 8–223 mL·min–1). There was no incidence of ITA hypoperfusion. Ninety-six patients underwent thallium stress scintigraphy before hospital discharge; 7 had small redistribution areas that in most cases could not be revascularized during surgery because of small coronary artery size. Ninety-eight patients were investigated by transthoracic coronary echography and all had good left ITA stem flow. There was one case (1%) of perioperative myocardial infarction. One patient experienced postoperative cerebellar bleeding from which she recovered without residual sequelae. One patient had mediastinitis, but he recovered completely. No operative mortality occurred.
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DISCUSSION
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Continuing graft patency is one of the important factors contributing to the long-term success of CABG. Thus, there has been growing interest in completely arterial revascularization.1–3,5–6 The arterial grafts utilized include the ITA, radial artery, and gastroepiploic artery.7–9 A recent report from Australia indicated that the medium-term patency rate of the radial artery as a free graft is not superior to that of the free right ITA or a saphenous vein graft.10 Suma and colleagues11 reported a 5-year patency rate of 87% for in situ gastroepiploic artery grafts. It appears that the ITA has the best long-term patency rate due to its inherent qualities, leading to attempts to achieve complete revascularization with the exclusive use of ITA grafts to maximize graft longevity and the results of CABG.
In 2001, Tector and colleagues12 reported intermediate-term results of CABG using ITA segments exclusively as T-grafts or sequential grafts in patients with triple-vessel disease. The technical feasibility rate of complete revascularization with exclusive use of the ITA, and the optimal design of the composite graft, has not been clearly defined. This retrospective study revealed that this aggressive approach using purely ITA revascularization was successful in 80% of patients, with good early results. Since some causes of failure were related to a lack of experience, we believe that we can improve the success rate as we gain more experience with this approach. Regarding the composite graft design, we used the in situ left ITA with a branched right ITA connected to the side of the left ITA in a Y- or T-shape most frequently to revascularize 3 vessels. The results indicate that this specific design has the best chance of achieving triple-vessel revascularization with the limited number and length of ITA grafts. Tector and colleagues12 used sequential grafts for 3 vessels in some patients, but we were not always able to achieve complete triple-vessel revascularization with an I-graft alone, mainly due to lack of graft length. We have no good explanation for this difference between our results and those of Tector and colleagues,12 but the difference in stature between the two patient groups may be a factor.
With this approach, there may be both benefit and risk in terms of long-term graft patency. By utilizing multiple sequential anastomoses, total flow through the graft may be increased. On the other hand, a graft to the right coronary system has to be brought to the posterior aspect of the heart, which could incur the risk of compromised flow. The overall impact of this approach should be determined by the long-term results. A major concern is the adequacy of bypass flow which has a single source of inflow for 3 vessels through the in situ ITA stem. Although no definite conclusion on whether the flow is sufficient can be reached until we have more experience with this approach, no case of ITA hypoperfusion in the acute phase occurred in our patients. Most of the patients had no residual ischemic lesions detected by thallium stress scintigraphy before hospital discharge. This probably reflects the adequacy of graft flow. We hope that intermediate-term results will allow us to reach a conclusion on the sufficiency of blood flow. The number of patients so far is relatively small, and because most of them were operated on in the last 3 years, follow-up data are naturally limited. Longer-term results are necessary to confirm the benefits of this procedure.
Part of this study was presented at the 34th Meeting of the Japanese Society for Cardiovascular Surgery, Osaka, Japan, February 18–20, 2004.
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REFERENCES
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- Tector AJ, Amundsen S, Schmahl TM, Kress DC, Peter M. Total revascularization with T grafts. Ann Thorac Surg 1994;57:33–9.[Abstract]
- El Nakadi B, Choghari C, Joris M. Complete myocardial revascularization with bilateral internal thoracic artery T graft. Ann Thorac Surg 2000;69:498–500.[Abstract/Free Full Text]
- Wendler O, Hennen B, Demertzis S, Markwirth T, Tscholl D, Lausberg H, et al. Complete arterial revascularization in multivessel coronary artery disease with 2 conduits (skeletonized grafts and T grafts). Circulation 2000;102(19 Suppl 3):III 79–83.
- Adachi H, Kamata S, Kodama K, Nagakura T. Vasorelaxant effect of a phosphodiesterase 3 inhibitor, olprinone, on isolated human radial artery. Eur J Pharmacol 2000;396:43–7.[Medline]
- Sauvage LR, Wu HD, Kowalsky TE, Davis CC, Smith JC, Rittenhouse EA, et al. Healing basis and surgical techniques for complete revascularization of the left ventricle using only the internal mammary arteries. Ann Thorac Surg 1986;42:449–65.[Abstract]
- Jones EL. Extended use of the internal mammary-coronary artery bypass. J Card Surg 1986;1:13–21.[Medline]
- Acar C. Radial artery grafting: clinical results. In: He GW, ed. Arterial grafts for coronary artery bypass surgery. Singapore: Springer, 1999;257–60.
- Suma H, Wanibuchi Y, Furuta S, Isshiki T, Yamaguchi T, Takanashi R. Comparative study between the gastroepiploic and the internal thoracic artery as a coronary bypass graft. Size, flow, patency, histology. Eur J Cardiothorac Surg 1991:5:244–7.[Abstract]
- Puig LB, Ciongolli W, Cividanes GV, Dontos A, Kopel L, Bittencourt D, et al. Inferior epigastric artery as a free graft for myocardial revascularization. J Thorac Cardiovasc Surg 1990;99:251–5.[Abstract]
- Buxton BF, Raman JS, Ruengsakulrach P, Gordon I, Rosalion A, Bellomo R, et al. Radial artery patency and clinical outcomes: five-year interim results of a randomized trial. J Thorac Cardiovasc Surg 2003;125:1363–71.[Abstract/Free Full Text]
- Suma H. Gastroepiploic artery grafting: clinical results. In: He GW, editor. Arterial grafts for coronary artery bypass surgery. Singapore: Springer, 1999:291–300.
- Tector AJ, McDonald ML, Kress DC, Downey FX, Schmahl TM. Purely internal thoracic artery grafts: outcomes. Ann Thorac Surg 2001;72:450–5.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
