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Ann Thorac Surg 1995;59:1509-1512
© 1995 The Society of Thoracic Surgeons

Reoperation in Patients With Closed SVG and Patent LITA–LAD Graft: T-Graft Approach

Infinity Heart Institute and St. Luke's Medical Center, Milwaukee, Wisconsin

Accepted for publication February 18, 1995.

	Abstract

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Selection of the bypass graft that the patient has demonstrated will remain patent and free from critical atherosclerosis is a most important part of coronary artery bypass reoperations. Sixteen patients in whom a patent left internal thoracic artery–left anterior descending coronary artery bypass graft and obstructed or closed saphenous vein grafts to other coronary arteries were visualized underwent reoperation. To reach the inadequately perfused circumflex and right coronary arteries, the right internal thoracic artery was anastomosed to the left internal thoracic artery as a T graft and then was attached to the circumflex and right coronary artery branches. All patients survived the procedure and are free from angina. There were no perioperative myocardial infarctions, and there was no suggestion of hypoperfusion by the grafts. We believe this technique may reduce the incidence of graft failure in patients undergoing reoperative coronary artery bypass grafting.

	Introduction

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See also page 1512.

Many patients who have coronary events or return of angina after coronary artery bypass grafting are found to have a widely patent left internal thoracic artery (LITA)–left anterior descending coronary artery (LAD) graft and obstruction or closure of the saphenous vein grafts (SVGs) to the circumflex and right coronary artery branches. These findings are demonstrated by postoperative graft visualization with angiography.

It is obvious to us that the coronary arteries being inadequately perfused by a diseased SVG should be rebypassed with an ITA graft that has been shown by the patient not to develop obstructing atherosclerosis. It is usually impossible to reach both the circumflex and right coronary artery branches with the attached right ITA (RITA) or the free RITA connected proximally to the aorta. To overcome this lack of length and to be able to bypass the remaining coronary arteries with an arterial graft, we [1] have employed the T-graft technique. This method brings the RITA closer to the circumflex and right coronary artery branches by anastomosing the proximal end of the RITA perpendicular to the side of the proximal LITA graft. We have performed the procedure in 16 patients with a preexisting LITA–LAD graft undergoing reoperative coronary artery bypass grafting.

	Material and Methods

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Patient Population
From October 1992 through September 1994, 16 carefully selected patients who had a patent, functioning LITA–LAD graft underwent reoperation to bypass the diagonal, circumflex, and right coronary arteries with only the RITA by use of a T graft and sequential distal bypass grafting. This represents 11.9% of a total of 135 reoperations for coronary artery bypass grafting performed during this period. All patients were seen with return of angina, and some had coronary events after the first operation. Age ranged from 43 to 75 years with an average age of 61 years. Three patients were women, and 13 were men. Two had left main disease, and 2 were diabetic. The left ventricular ejection fraction ranged from 0.20 to 0.59. Eleven patients had two RITA coronary anastomoses, and 5 had three. The average number of grafts per patient was 2.47. Each patient was carefully observed for death, hypoperfusion syndrome, perioperative myocardial infarction, need of postoperative cardiac support, bleeding, wound complications, and strokes. Intraoperative transesophageal echocardiograms were obtained from all patients.

Operative Technique
The previously made sternotomy incision is reentered, and the heart is dissected free from the posterior wall of the sternum beginning at the xiphoid and proceeding to the sternal notch. Care is taken to saw the sternum exactly in the middle of the bone. This is important in preventing wound dehiscence in the postoperative period. Adhesions between the heart and the pericardium as well as the mediastinal structures are dissected with scissors. The inferior surface of the heart is mobilized after the patient is placed on cardiopulmonary bypass.

EXPOSURE OF LITA.
The heart and the pericardium are dissected from the posterior wall of the left side of the chest in a manner similar to that used for mobilizing the LITA from the chest wall. The surgeon must be careful to recognize whether only a distal portion of the LITA was dissected at the first operation, as it is very easy to injure the LITA where it is still attached to the chest wall. In this situation, sometimes the only safe way to mobilize the LITA is to separate it from the ribs and intercostal muscles with a knife, with care taken to cut against the chest wall structures. The LITA–LAD graft is usually located between the lung and the pericardium near the left phrenic nerve and enters the heart through an incision made in the pericardium. Dissecting the left lung from the pericardium will lead the surgeon to the LITA graft.

Once the LITA is located, the artery is prepared by dissecting it free from its surrounding tissues at the level of the left atrial appendage using sharp dissection. The LITA should also be encircled at a site 4 to 6 cm proximal so a bulldog clamp can be placed at the time the aorta is cross-clamped.

DISSECTION AND PREPARATION OF RITA.
The right lung is released from the chest wall if there are adhesions. Dissection of the RITA begins at its bifurcation into the superior epigastric and musculophrenic branches and extends to the thoracic inlet [2]. The surgeon must be careful not to injure the right subclavian vein or the phrenic nerve. The artery is dissected free from its pedicle to gain as much length as possible before it is clipped multiple times and transected at its origin at the right subclavian artery.

The fascia, fat, and muscle on the posterior surface of the RITA are opened longitudinally down to its adventitia. Ten milliliters of a 1:30 solution of papaverine hydrochloride and saline solution [3] is gently infused into the proximal end of the artery after the distal end is occluded with a bulldog clamp. All bleeding sites are clipped or oversewn with sutures.

T-GRAFT TECHNIQUE.
An arterial cannula is placed into the ascending aorta or aortic arch, and a two-stage cannula is placed into the right atrium. After the start of cardiopulmonary bypass, the remainder of the heart is dissected from the pericardium, and the coronary arteries to be bypassed are identified. The aorta is cross-clamped, and antegrade and retrograde cardioplegia [4] is administered. The proximal LITA is clamped with a bulldog clamp, and a 1-cm vertical arteriotomy is made in the LITA on its antero-left lateral side at a site adjacent to the left atrial appendage. The LITAs were 2 to 4 mm in diameter. The bulldog clamp is released to test the flow in the LITA.

The proximal end of the RITA is cut cleanly, spatulated, and sewn perpendicular to the side of the LITA with a continuous 8-0 monofilament suture (Fig 1) [1]. The anterior edges are sutured first, beginning at the side of the RITA and the proximal end of the LITA. The RITA is then lifted out of the mediastinum to expose the posterior edge, and the anastomosis is completed. The bulldog clamp is released, and flow in the RITA is tested. If it is inadequate, the anastomosis should be redone. If the flow is continuous and has a good stream, it is considered sufficient; flow is not quantified because the patients are on cardiopulmonary bypass. The RITA pedicle is attached to the LITA or epicardium with 5-0 silk sutures to prevent twisting of the graft or tension of the anastomosis (see Fig 1).

View larger version (124K): [in this window] [in a new window]   Fig 1. . Technique of free right internal thoracic artery (RITA) anastomosis to existing left internal thoracic artery (LITA) bypass graft using 8-0 monofilament suture to form a T graft. (A) The anterior edges are sutured first, beginning at the proximal end of the LITA. (B) The RITA is lifted out of the mediastinum to expose the posterior edges, and the anastomosis is completed. (C) The completed T graft anastomosis. The RITA lies posteriorly out of view.

The patient is weaned from cardiopulmonary bypass. The transesophageal echocardiogram is evaluated for wall motion abnormalities, and the electrocardiogram is observed for ischemic changes. Changes in the electrocardiogram or wall motion are strong indicators of hypoperfusion. Often they can be corrected by altering the attachment of the graft pedicle to the heart or redoing an anastomosis.

The sternum is closed with 12 single stainless-steel wires to obtain a more secure approximation of the sternal tables and to prevent sternal dehiscence and later infection, which occur more frequently after bilateral ITA dissection. Most of the wires are placed transsternally; a few are inserted peristernally.

	Results

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 
There were no injuries to the preexisting LITA–LAD graft. No patients have died early or up to 2 years after the operation; 9 patients have been followed up for more than a year. Four patients required inotropic support for a brief period, and 1 had an intraaortic balloon pump. Hypoperfusion was not detected by new wall-motion abnormalities on transesophageal echocardiography or by ischemic electrocardiographic changes. No changes in septal wall motion were observed. None of the patients sustained a perioperative myocardial infarction. There were no sternal wound dehiscences or infections. Postoperative angiograms have not been performed.

	Comment

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 
Graft failure is the most common undoing of the benefits patients derive from coronary artery bypass grafting. Obviously the surgeon can greatly influence the long-term outcome of myocardial revascularization by the type of graft he or she selects [6, 7]. These 16 patients demonstrated long-term success of the ITA graft and failure of the SVG after the first operation. Because the patient has demonstrated that his or her own ITA graft will remain patent much longer than his or her SVG, it seems prudent to select the other ITA instead of an SVG at reoperation. Avoidance of leg incisions is another advantage of not using the SVG.

The major disadvantage of this operation is the chance of injuring the patent, working LITA–LAD graft that is essential to the patient's life. As we have performed more reoperations in patients with functioning LITA–LAD grafts, we have become accustomed to the presence of the graft and rarely injure it. Experience and precision are essential to the success of this procedure. We caution surgeons using this technique without prior experience with T grafts.

This procedure is applicable only when the patient has a patent, unobstructed LITA and an unobstructed RITA that is free from critical atherosclerosis and injury. Although it did not occur in this group of patients, it is possible that in a patient with a very large dilated left ventricle, the RITA might not reach the posterior descending coronary artery. Other arterial conduits such as the right gastroepiploic artery and inferior epigastric arteries could be used if the RITA is not an acceptable graft.

Another concern is that after it is attached to the LITA, the RITA may diminish flow to the LAD and result in hypoperfusion [8, 9] to the anterior septal and lateral myocardium. This has not occurred in this group of patients. More convincing evidence regarding the ability of the LITA to supply the entire ischemic myocardium with blood relates to our results in performing this procedure in 560 patients. The incidence of hypoperfusion has been minimal in this group and can usually be detected before the patient is weaned from cardiopulmonary bypass. Most of the instances of hypoperfusion were caused by technical errors in constructing the anastomosis or fixation of the ITA to the epicardium and were readily corrected.

We prefer the RITA because the ITA is the most ideal bypass graft in nearly all patients undergoing coronary artery bypass grafting [1]. In our attempt to prevent long-term bypass graft failure, we believe that using the RITA in coronary artery bypass reoperations when there is a patent LITA–LAD graft may greatly extend the long-term benefits resulting from the second revascularization.

	Footnotes

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Address reprint requests to Dr Tector, 2901 W Kinnickinnic River Pkwy, Milwaukee, WI 53215.

	References

Top Footnotes Abstract Introduction Material and Methods Results Comment References

 

1. Tector AJ, Amundsen S, Schmahl TM, Kress DC, Peter M. Total revascularization with T grafts. Ann Thorac Surg 1994;57:33–9.[Abstract]
2. Tector AJ, Schmahl TM. Techniques for multiple internal mammary artery bypass grafts. Ann Thorac Surg 1984;38:281–6.[Abstract]
3. Mills NL, Bringaze WL. Preparation of the internal mammary artery graft. Which is the best method? J Thorac Cardiovasc Surg 1989;98:73–9.[Abstract]
4. Buckberg GD. Antegrade/retrograde blood cardioplegia to ensure cardioplegic distribution: operative techniques and objectives. J Cardiac Surg 1989;4:216–38.[Medline]
5. Navia D, Cosgrove DM III, Lytle BW, et al. Is the internal thoracic artery the conduit of choice to replace a stenotic vein graft? Ann Thorac Surg 1994;57:40–4.[Abstract]
6. Loop FD, Lytle BW, Cosgrove DM, 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]
7. Tector AJ, Schmahl TM, Janson B, Kallies JR, Johnson G. Internal mammary artery graft: its longevity after coronary bypass. JAMA 1981;246:2181–3.[Abstract/Free Full Text]
8. Jones EL, Lattouf OM, Weintraub WS. Catastrophic consequences of internal mammary artery hypoperfusion. J Thorac Cardiovasc Surg 1989;98:902–7.[Abstract]
9. Barner HB. Use of the internal thoracic artery: simple, complex, or with a backup? [Editorial]. Ann Thorac Surg 1994;57:8–9.[Medline]

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This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tector, A. J. Articles by Schmahl, T. M. Search for Related Content PubMed PubMed Citation Articles by Tector, A. J. Articles by Schmahl, T. M.