The Aorta-to-Coronarv Radial Arterv

Transcription

1 THE ANNALS OF THORACIC SURGERY Journal of The Society of Thoracic Surgeons and the Southern Thoracic Surgical Association VOLUME 16 * NUMBER z - AUGUST 1973 The Aorta-to-Coronarv Radial Arterv Bypass Graft A Technique Avoiding Pathological Ch.anges in Grafts Alain Carpentier, M.D., J. L. Guermonprez, M.D., A. Deloche, M.D., Claude Frechette, M.D., and Charles DuBost, M.D. ABSTRACT A technique of aorta-to-coronary artery bypass grafting using the patient s radial artery is proposed with the aim of reducing the incidence of late pathological changes in the graft. Experience with 40 radial artery grafts in 30 human patients has shown excellent short-term results and has demonstrated the primary importance of mechanical dilation of the arterial graft before implantation to counteract its spasm. Even though several advantages favor use of the radial artery over the vein for grafting (arterial structure, elasticity, regularity of the lumen) and over the mammary artery (graft size and length, resistance of the arterial wall), the ultimate fate of the radial artery graft needs a longer follow-up to be determined with certainty. T, he saphenous vein-to-coronary artery bypass technique gave surgery of the coronary arteries the rebirth of respect it needed. The existence of progressive modifications of the venous graft, as first noted by Johnson and colleagues [6], does not in any sense raise doubts as to the excellence of venous grafting and its results. However, the complication of subintimal fibrosis presses us to find solutions in the event that it is shown to be a real problem in the future. The incidence of subintimal fibrous proliferation varies (4 to 32%) according to different authors [4-71. There have been numerous hypotheses From the Department of Cardiovascular Su.rgery, Broussais Hospital, and the Laboratory for Study of Cardiac Grafts and Prostheses (C.N.R.S.), Paris, France. Presented at the Ninth Annual Meeting of The Society of Thoracic Surgeons, Houston, Tex., Jan , Address reprint requests to Dr. Carpentier, HBpital Broussais, 96,.rue Didot, Paris, France. VOL. 16, NO. 2, AUGUSr,

2 CAKPENTIEK ET AL. about its causes, among which arterial pressure appears to be a factor of primary importance [2, 111. The aim of this paper is not to discuss the incidence or the possible causes of this venous graft disease, but simply to propose a solution that can avoid it altogether. In seeking a substitute vessel we, like others, started out using the internal mammary artery. Those who have used this vessel know its disadvantages. The lumen is often too small as compared with that of a coronary artery; the dissection is tedious; the arterial wall is fragile and tends to dissociate in the distal segment due to suturing; and the length is often insufficient to permit a bypass of the right coronary artery as well as of a distal branch of the left. The radial artery appeared to us to have several advantages over the mammary artery for coronary bypass. The lumen is 2 to 2.5 mm. in diameter; the superficial disposition of this artery renders it easy to remove; the arterial wall is resistant and suitable for suture; and the mean length is 22 mm., which easily permits construction of two bypass grafts. Ischemia of the hand need not be anticipated, since the ulnar artery is largely anastomosed with the radial artery in this area. Finally, damage due to arteriosclerosis seems to be rare in the radial artery as demonstrated by anatomical and histological studies of 50 specimens. Technique STUDY OF VASCULARIZATION OF THE HAND To avoid any ischemic accidents due to abnormal arterial distribution, the blood supplied to the hand by the ulnar artery alone was verified in every case (Fig. 1). Before the operation the return to normal of both temperature and color of the hand after compression with an elastic BEFORE OPERATION DURING OPERATION FIG. 1. Evaluation of vascularization of the hand. Before operation (a) the hand is compressed with an elastic bandage. (b) The return to normal of the temperature and color under persistent compression of the radial artery is studied after bandage removal. (c) During operation, after partial section of the arte?, the proximal segment is clamped. Retrograde blood flow from the distal segment is observed. 112 THE ANNALS OF THORACIC SURGERY

3 Aorta-to-Coronary Radial Artery Bypass Graft FIG. 2. Removal of the radial artery. (a) Incision. (b) Removal of the artery. (c) Removal of the artery with its satellite veins. bandage had to be as rapid as they are normally despite continuous compression of the radial artery at the wrist. During operation an additional precaution was taken: before complete section of the artery, retrograde blood Row from the distal segment was evaluated. REMOVAL OF THE ARTERY The entire forearm was incised (Fig. 2). Two types of removal were used. In 6 instances the artery was taken alone after successive ligation of its collaterals. In other instances the artery was removed with its satellite veins and contiguous tissue in order to preserve the vascularization of the artery itself. Correction of arterial spasm, which always appeared after removal of the artery, was shown to be of primary importance. Since drugs reputed to suppress arterial spasm were shown to be incompletely effective, a series of dilators ranging from 1 to 3 mm. in diameter have been used to mechanically dilate the artery to the caliber of the coronary artery to be bypassed (Fig. 3). During this procedure the lumen was filled with heparinized blood to avoid all trauma to the endothelium. If the caliber of the distal bed of the coronary FIG. 3. llilators used to dilate the graft to the proper diameter according to the coronary artery bed. Marks on the shaft of the dilator allow measurement of the length of both the graft and the coronary arterial bed. VOL. 16, NO. 2, AUGUST,

4 CARPENTIER ET AL. FIG. 4. Scissors designed for fashioning the arteriotomy: (a) aortic type; (b) coronary type. artery was 2.5 mm., a 2.5 mm. dilator was used to dilate the radial artery progressively; if it was 2 mm., a 2 mm. dilator was chosen; and so on, so that an exact coaptation of both arteries was obtained (see Fig. 6). CORONARY BYPASS GRAFTING The technique of suturing the graft to the coronary artery and to the aorta had no particular originality except for the following details. First, the coronary artery incision was shaped at its two extremities by specially designed scissors (Fig. 4). This allowed a better anastomosis than that obtained with a simple linear incision. A continuous suture was used on the sides of the anastomosis and interrupted sutures at the two ends in order to preserve arterial expansivity. In 8 patients with complete obstruction of the coronary artery, the anastomosis was of the terminalterminal type using interrupted sutures (Fig. 5). Second, special scissors were used to shape the incision on the aorta as well. In 1 instance the aortic wall was thick and hypertrophied with areas of severe atherosclerosis and fibrous deposits that rapidly obstructed the proximal anastomosis of the graft, making reoperation necessary. At that time the following technique was used: a 3 x 3 cm. square portion of the aortic wall was excised and replaced by a Dacron patch, and the proximal end of the graft was reimplanted at its center. In this manner the fibrous proliferation at the incised area of the aortic wall was kept at a distance from the anastomosis (Fig. 6). R es u 1 t s Forty bypass grafts were performed in 26 men and 4 women whose ages ranged from 35 to 65 years with a mean age of 49. In each patient the 114 THE ANNALS OF THORACIC SURGERY

5 A ol-t (1-1 o-coronary Radial Artery Byfiass Gruf t FIG. 5. Aorta-to-coronary radial artery bypass graft. (a) Terminal-terminal radial arteqito-cinlerior tlcscendirig coronary artery anastomosis (6 months). (b) Terminal-lateral radial nrteiy-to-lef/ mcirginnl artery anastornosis. (c) Terminal-termincrl radial artery-to-right coronary artery (ina.ctomosi.c. (d) Spasm in a radial artery bypass graft (the artery 7uas not mechanically dilated before implantation). For a, b, and c, note that the radial artery rc.mtiined exactly adapted to the diameter of the coronary artery. indication for operation was the coexistence of severe angina pectoris with coronary arteries that appeared suitable for operation according to the angiographic examination. In 1 patient the operation was indicated because of an impending infarction. The sites of the coronary anastomosis were as follows: right coronary artery, 9; anterior descending, 17; first diagonal, 5; left marginal, 9. There were no hospital deaths. Early complications were a mediastinal hematoma and a disesthesia of the thumb. Clinically the pain completely disappeared in all patients but 3. For them, pain returned early after the operation. Coronary angiography control studies in all patients between one and ten months after operation showed that all grafts were patent, 3(i had a normal, regular lumen (see Fig. 5a-c), and 3 had a reduced caliber (see Fig. 5d). The latter were 3 of the first 6 patients in our series. Their VOL. 16, NO. 2, AUGUST,

6 FIG. 6. Technique of inserting the proximal segment of the graft on the center of a Dacron patch, used when the aorta is severely hypertrophied and sclerotic. This allows one to kefp the aorta at a distance from the anastomosis, thus allaying postoperative fibrous and Jibrinous proliferation. grafts at the time of operation had not been mechanically dilated. This complication was definitely eliminated later on by systematically dilating the arterial graft. One of the 3 patients had to undergo reoperation because of important residual pain. He is now asymptomatic, and his control coronary angiography is satisfactory. Finally, 1 patient s graft developed stenosis at the proximal anastomosis due to atherosclerotic thickening of the aortic wall. He was reoperated upon using the technique described above, and his graft was reimplanted in the center of a large Dacron patch (see Fig. 6). Comment The incidence and cause of subintimal fibrosis of vein grafts are unknown. Johnson and associates [6] first described 15 cases of narrowing of vein grafts in an early series. Lespbrance and co-workers [7] reported a large series of patients who underwent early and late postoperative coronary angiography. The early postoperative studies showed a patency rate of goyo, while rate evaluation showed a patency rate of 72y0. Most grafts displayed some reduction in size at the second study. This reduction of caliber was moderate to severe (> 40% reduction) in 30y0 of the remaining patent grafts. Localized or diffuse narrowing has also been described in femoropopliteal vein grafts [3, 61. While the true cause is not known, several factors have been implicated. Venous valves may be responsible for segmental stenosis. The reponse to arterial pressure is of primary importance in explaining the 116 THE ANNALS OF THORACIC SURGERY

7 Aortu-to-Coronary Radial Artery Z3ypa.s~ Graft diffuse stenosis, as demonstrated by Vlodaver and Edwards [ 111. Ischemia may also play a role [Z]. These data point out the need for another type of graft and support our preference for a graft of the arterial type. In addition, the use of grafts other than the saphenous vein to perform an aorta-to-coronary artery bypass may be a necessity if there are extensive varicose veins or if coronary vein bypass after several months shows a fibrous subintimal proliferation, making reoperation necessary. In these cases the use of either the internal mammary artery or of a vein taken from the arm and placed in a Dacron tube to prevent extensive dilatation (Favaloro s technique) has been proposed. The inconvenience of using the internal mammary artery has been discussed above, and Favaloro s technique is relatively complicated and there is the same risk of subintimal fibrosis. The use of the patient s radial artery has several advantages as compared with these techniques. It is easily removed; the arterial wall is resistant enough to permit a satisfactory suture; and the length of the artery is sufficient to permit construction of two bypass grafts. As we have already emphasized, the only precaution that must be taken when using the radial artery is to mechanically dilate the artery to counteract its spasm. This has permitted us to eliminate the complications observed at the beginning of our experience, when a persistent spasm of the artery was responsible for residual pain. This also permitted us to adapt the size of the radial artery exactly to that of the coronary artery, thus improving hemodynamic function. Except for the special indications we have mentioned, the question of whether radial artery bypass should and must be used routinely in coronary surgery must be examined. In other words, can it be considered to have a better chance for long-term durability than a saphenous vein bypass? Two immediate advantages favor a radial artery bypass as compared with a venous bypass: the graft size is exactly adapted to the coronary artery, and the elasticity of the arterial wall and the regularity of the lumen provide physiological flow. But the main point concerns the comparative long-term evolution of both types of grafts, and it must be ascertained whether the arterial bypass is threatened by the same modifications as those observed in venous grafts. It is too early to answer this question, but the preservation of viability of the arterial graft in the present series, the usual absence of arteriosclerotic lesions in the radial artery, and the fact that the radial artery is adapted to an arterial flow would all seem to be favorable factors in preventing late pathological changes in the graft. However, this will have to be demonstrated accurately with a longer follow-up. References 1. Bourassa, M. G., Lespkrance, J., Campeau, L., and Simard, P. Factors influencing patency of aortocoronary vein grafts. Circulation (Suppl. 1):79, VOL. 16, NO. 2, AUGUST,

8 CARPENTIER ET AL Brody, W. R., Angell, W. W., and Kosek,. C. Histologic fate of venous coronary artery bypass in dogs. Am. J. Patho! 66: 130, DeWeese, J. A., and Rob, C. G. Autogenous venous bypass grafts five years later. Ann. Surg. 174:346, DuBost, C., Carpentier, A., Courbier, R., and Baille, Y. Chirurgie de la maladie coronarienne. J. Chir. 104:213, Grondin, C. M., Meere, C., Castonguay, Y. R., Lepage, G., and Grondin, P. Progressive and late obstruction of aorto-coronary venous bypass graft. Circulation 43:698, Johnson, W. D., Auer, 1. E., and Tector, A. J. Late changes in coronary vein grafts (abstract). Am. J. Cardiol. 26:640, Lespkrance, J., Bourassa, M. G., Saltiel, J., and Grondin, C. M. Late changes in aortocoronary vein grafts: Angiographic features. Am. J. Roentgenol. Radium Ther. Nucl. Med. 116:720, McNamara, J., Darling, R. C., and Linton, R. R. Segmental stenosis of saphenous vein autografts. N. Engl. J. Med. 277:290, Marti, M. C., Bouchardy, B., and Cox, 1. N. Aorto-coronary bypass with autogenous vein grafts: Histopathological aspects. Virchows Arch. [Pathol. Anat.] , Morris, G. C., Reul, G. J., Howell, J. F., Crawford, S. E., Chapman, D. W., Beazley, H. L., Winters, W. L., Peterson, P. K., and Lewis, J. M. Follow-up results of distal coronary artery bypass for ischemic heart disease. Am. J. Cardiol. 29: 180, Vlodaver, Z., and Edwards, J. E. Pathologic changes in aorto-coronary arterial saphenous vein grafts. Circulation 44:719, Addendum Since this article was submitted for publication the results have remained good. No long-term modification in the patency of the grafts and no ischemic complications of the hand have been observed. Nevertheless, spasm of the arterial graft, which occurs immediately after its removal in 25y0 of the patients, remains the chief problem. The best method to counteract this spasm is the use of papaverine for local washing during operation and intravenously afterward for a period of fifteen days. Discussion DR. GEORGE. GREEN (New York, N.Y.): I believe that Dr. Carpentier and his colleagues are making an important contribution to the techniques of coronary surgery. I think the search for and use of arterial autografts is important. I would like to respond to his comments about mammary anastomosis based on my experience with it in 371 patients. As for the lumen of the mammary artery being too small, in about 10% of patients it is too small but in 90% it is very good; and in that 90% the flow from the cut end averages 135 ml. per minute. The dissection of the mammary artery is not tedious if one uses electrocautery, in which case the vessel can be taken down in 15 to 20 minutes. The wall of the mammary artery is fragile, but I have not found it to be more so than the coronary artery wall. As to insufficiency of length, it is important to free the artery to its origin at the top of the first rib. After transecting the artery distally and before bypass is instituted, mark the length to which the artery will reach on the epicardium with a silk stitch, and then there will not be any mistakes about insufficient length. To summarize my experience, I started using the mammary artery for anastomosis to the anterior descending coronary artery but did alternate patients 118 THE ANNALS OF THORACIC SURGERY

9 with saphenous vein grafts. The data accumulated over the course of the past five years leave no question in my mind about the superiority of the arterial autograft. During the past few months I have been alternating mammary anastomoses with saphenous vein grafts to the circumflex artery. The left mammary artery will reach the circumflex main trunk, high lateral branch, or posterolateral branches. I currently use mammary anastomosis as the procedure of choice for the circumflex as well as the anterior descending coronary arteries. The right mammary artery is anastomosed to the anterior descending and the left to tlie circumflex coronary artery. I have on four occasions used Dr. Sterling Edwards s procedure of bringing the splenic artery up through the diaphragm to tlie riglit coronary artery, to which it makes a very satisfactory pedicle graft. Arterial pedicles are available for all three coronary arteries. As stated by Dr. Edwards, an advantage of a pedicle graft is the elimination of an aortic anastomosis. Not all aortas are a satisfactory site of origin for either a vein or an artery. However, I do believe that the radial artery technique will contribute to the further advancement ol coronary surgery. DR. KOI~ERT D. BLOODWELL (Orlando, Fla.): For a long time we sought some answer to the reports of lack of patency in vein grafts. Reports of long-term patency with internal mammary grafts have been very encouraging, antl each of us has been wondering what artery is not so inclispensable that it cannot be moved. Our medical antl cardiology colleagues in many institutions have demonstrated that brachial and radial arteries can be occluded with regularity and still leave the hands in viable condition. Clinical examination of the patient by the Allen test is very similar LO the diagram Dr. Carpentier showed us. Tlie hand is clenched, thus causing ischemic pallor to the palm, and then both the radial and ulriar arteries are compressed. When the hand is opened you can see its rapid flushing as the ulnar artery is released, and this substantiates without arteriography the patency of the carpal collateral circulation. In Orlando we have grafted only 35 patients with the radial artery, using it in a 10 cm. length to the anterior descending coronary artery. The spasm is a problem that I am not quite sure how to deal with. Tlie vessel microscopically has much more muscle in its wall than the coronary artery itself. I think taking the contiguous tissue and veins is perhaps unnecessary. If these bands are indeed adventitial bands about the radial artery, when the vessel is in place they can often be incised. There is no doubt about the discrepancy in size of veins or radial artery at the aortic anastomosis. In the patients we have operated upon, we have been quite satisfied with the clinical result. We have no arteriograpliy to support this statement, however. The radial artery is a definite adjunct if you are disposed to use a structure other than the mammary artery or saphenous vein as an autologous arterial graft. DR. JOHN H. KENNEDY (Houston, Tex.): I too would like to commend Dr. Carpentier for this innovative procedure and to comment on the occurrence of presumably obstructive lesions in patients who have undergone reconstruction with radial arteries, just as occurred in the series he meritionctl in introducing the discussion of saphenous vein bypass grafts. We have experimental evidence to suggest that obstructive lesions are a hydraulic disease. A number of factors govern runofl. One that is difficult to control is the character of the hydraulic orifice made between the side-lxanch and the aorta, and this varies from surgeon to surgeon. The index of flow in the sidebranch antl in tlie major trunk may be plotted against the angle theta. It is of interest that thus far all the patients reviewed in the Methodist Hospital VOL. 16, NO. 2, AUGUST,

10 CAKPENTIER ET AL. experience who have had an occlusive lesion in a vein bypass graft have fallen along the same curve, which shows that ideal flow and fewer occlusive lesions of the vein occur when the side-branch leaves at an angle of 90 degrees. DR. DONALD B. EFFLER (Cleveland, Ohio): Speaking for the Cleveland Clinic group, I would like to echo the sentiments of Dr. Green. We believe that the internal mammary artery is an extremely versatile vessel and would like to suggest that it is applicable in a free graft position. My two colleagues, Dr. Cheanvechai and Dr. Loop, have operated upon more than 500 patients with mammary-to-coronary artery anastomoses; about 60 of these procedures used the mammary artery as a free graft between aorta and coronary artery. The mammary artery is eminently suited for free grafting. It is small, but we have found that it does respond to local applications of papaverine, seems to dilate quite satisfactorily, and in the majority of patients is quite acceptable. A total of 60 free grafts have been used, the majority of them to the anterior descending, 2 to the diagonal, 3 to the right, and 5 to the circumflex coronary artery. A small number of patients have been restudied, 8 to be exact, and all have working, patent grafts. 1 think our French colleagues have done an excellent piece of work. However, we have considerable reservation as far as the radial artery graft is concerned. I really think they should be a little more charitable toward the internal mammary artery. After all, it did get us into revascularization, and it is still an excellent vessel to use. DR. W. STERLING EDWARDS (Albuquerque, N.Mex.): I too believe firmly that arteries will prove to be more durable coronary bypass grafts than veins. I must disagree with Dr. Carpentier s statements, however, about the difficulties in using the internal mammary artery. Since 1969 we have routinely used the internal mammary artery for bypass grafts to the branches of the left coronary system, the anterior descending, and the circumflex coronary arteries. Both mammary arteries can be taken down entirely with cautery, requiring 15 to 20 minutes each, and mammary-to-coronary anastomosis has become quite simple with the use of 2X loops and 7-0 or 8-0 suture. Our long-term patency rate is 97%. From the standpoint of developing a technique for complete coronary revascularization using arteries, the problem is the right coronary artery. Mammary arteries will not reach to the diaphragmatic surface of the heart, where the healthiest segment of the right coronary artery is usually found. We have recently used the splenic artery in 20 patients, removing the spleen and freeing the artery back to the celiac axis. The splenic artery is then brought through the diaphragm and sutured to the distal right coronary artery. In a recent patient who had had splenectomy for thrombocytopenic purpura we used the radial artery for aorta-to-right coronary bypass, as recommended by Dr. Carpentier, and were pleased with its size, which closely approximated the coronary artery, and with its ease of handling and suturing. I believe that use of the radial artery will find a place in coronary artery surgery. DR. EARLE B. KAY (Cleveland, Ohio): In a two-year period 1,800 catheterizations were performed in patients with predominant coronary artery disease. A number of these patients had sclerosis not only of their coronary arteries but in general, including the brachial and radial arteries. In this group of 1,800 patients, 38 had to be reoperated upon to relieve brachial artery obstruction following catheterization. Three patients ended up without radial pulses, and 1 of these patients now has brought a medicolegal suit. Therefore I would be reluctant to deliberately use the radial artery as a bypass donor artery. I would also be concerned about the incidence of sclerotic disease in radial arteries. 120 THE ANNALS OF THORACIC SURGERY

11 Aorta-to-Coronary Radial Artery Bypass Graft We have preferred to use the internal mammary artery for bypass during the past four and one-half years. We have used the artery bilaterally in more than 250 patients in all locations anteriorly and posteriorly. There have been no locations that could not be reached. In 3 instances it was necessary to detach the proximal end and anastomose it to the aortic root. We stress complete isolation up to the subclavian artery to get length and also to get those additional high branches in order to make sure that all the flow is going through the internal mammary into the coronary artery rather than to the mediastinum. It has been possible to reach the posterior descending branch of the right coronary artery or circumflex coronary artery without any great difficulty. These patients are now being reevaluated after a period of one, two, three, and some four years postoperatively. The patency rate has been almost 100~o in those we have restudied so far, approximately 40 to 50 patients. Only 1 graft has been occluded. DR. CARPENTIER: We have had some experience with the internal mammary artery, and I think the magnification techniques utilized by Dr. Green may explain why he is able to minimize the difficulties we have encountered because of the fragility of this artery. I don t think, though, that the discussion should be on the difference between the radial artery and the mammary artery; it should be between venous tissue and arterial tissue. The point would be to learn the true incidence of venous subendothelial proliferation and the comparative hemodynamic function of venous grafts and arterial grafts, and this will require further investigation. In response to Dr. Kennedy s comments, I am not convinced that mathematics is more important than hemodynamics and biology in the understanding of such problems. VOL. 16, NO. 2, AUGUST,