Toward a Rational Operation for Transposition of the Great Arteries

Transcription

1 Toward a Rational Operation for Transposition of the Great Arteries C. E. Anagnostopoulos, M.D.,* C. L. Athanasuleas, A.B., and R. A. Arcilla, M.D. ABSTRACT Current methods for physiological correction of transposition of the great arteries are well established. Continuing morbidity is associated with them, however. The development of hypothermic open-heart surgery and the perfection of microsurgical techniques coupled with our observations of favorable coronary anatomy in many patients with transposition lead us to suggest that the time is ripe for attempts at complete anatomical correction. Our experimental background and several alternatives are suggested. T ransposition of the great arteries (TGA), one of the most common lethal congenital cardiovascular anomalies [ 131, continues to challenge cardiologists and cardiac surgeons. Although our ingenuity over the past decade has been directed toward solving the riddles of TGA, it remains a persistent enigma, thus far elusive to simple total correction. Despite intensive efforts combining the best medical and surgical techniques, a 50% one-year mortality has been reported in two large series of 300 patients [14], although improved survival has been observed in other, smaller series. Surgical approaches aimed at increasing atrial mixing or diverting atrial flow frequently do not result in asymptomatic long-term survival because of problems inherent in the technique and physiology of the atrial baffle operation. Although the well-known conduction disturbances can be minimized [211, progressive obstruction of the venous inflow with pericardial [ 191 or artificial [ 161 patches, tricuspid insufficiency [5, 201, right ventricular dysfunction [5], as well as persistent shunts have been reported [12, 161. Since the atrial baffle operation results in, at best, a corrected transposition complex with its own set of problems in later age, this surgical approach may not be regarded as ideal. Currently, the difficult problem of subpulmonic stenosis is found at birth in approximately 8% of transpositions, and its incidence appears to increase in frequency later [ 151. In our own review of 589 reported atrial baffle operations for TGA, with or From the Divisions of Thoracic and Cardiovascular Surgery and Pediatric Cardiology, University of Chicago, Chicago, 111. *Established Investigator, American Heart Association. Accepted for publication June 28, Address reprint requests to Dr. Anagnostopoulos, Department of Surgery, University of Chicago Hospitals, 950 E. 59th St., Chicago, Ill THE ANNALS OF THORACIC SURGERY

2 Rational Operation for Transposition without associated defects, the 30-day mortality was 21yo. At five years 37y0 of the original patients had died and an additional 30% had developed significant complications. It is no surprise, therefore, that disillusionment with current methods abounds [lo, 111. In the face of these not-too-encouraging short-term and long-term results of the atrial baffle operation has come the realization that the techniques required for direct correction of TGA may now be available. The possibility of a direct approach has been enhanced by the combined experiences of the various surgical specialties: microsurgery with optical assistance, hypothermia for operating upon the newborn, and coronary artery surgery. Until prenatal diagnosis becomes available, the creative cardiologist and cardiac surgeon should perhaps reconsider their current therapies for TGA and attempt other, more rational ones-in particular, direct restoration of the normal anatomical pathway. Such a direct approach was in fact initiated in 1961 by Idriss and associates [S]. In their operation, a circumferential rim of aorta together with the coronary ostia is resected and rotated onto a new site over the transected pulmonary artery, followed by simple switching of the great vessels (Fig. 1). Methods We have been investigating in the laboratory the feasibility of a number of these approaches for direct TGA correction (Fig. 2). In the absence of a ventricular septa1 defect, these procedures would be applicable in the newborn with adequate left ventricular pressure. 1. One such corrective procedure involves the construction of a common aortopulmonary trunk. A prosthetic or autologous tissue tube is sutured within the aorta, proximally at a level between the coronary arteries and aortic valve and distally within the distal pulmonary trunk. This results in right ventricular outflow directly to the lungs. The left ventricle in such an arrangement empties into the proximal pulmonary trunk, then into the common aortopulmonary trunk, and finally into the aorta and coronary arteries. FZG. 1. Switching of the great vessels after a circumferential rim of aorta together with the coronary ostia has been resected and yotated onto a new site over the transected pulmonary artery, as suggested by Zdriss and associates [8]. VOL. 16, NO. 5, NOVEMBER,

3 ANAGNOSTOPOULOS ET AL. FIG. 2. Possible methods of direct correction of transposition of the great vessels. 1, construction of a common aortopulmonary trunk. 2, variation of 1 using the pulmonary artery itself as the conduit instead of a graft. 3, switching the aorta and the pulmonary artery. 4, switching the pulmonary artery and the aorta with detachment of the coronary arteries at the ostia together with a rim of aortic tissue and their anastomosis onto the proximal ascending aorta at its new site. 5-8, irarialions for patients in whom direct subcoronary switching or switching with reimplantation is not feasible due to the anatomical positions of the coronary ostia. 2. A variation of this procedure consists of using the pulmonary artery itself as the conduit in place of the graft. A patch is then sutured to the aortotomy in such a manner as to direct flow from the left ventricle through it, around the pulmonary artery, and into the aorta and coronary arteries. Results of such trials in short-term experiments in animals have been promising [ THE ANNALS OF THORACIC SURGERY

4 Rational Operation for Transposition 3. In experimental work on small animals such as the 5- to 10-pound newborn pig, we have confirmed the feasibility of an operative switch of the aorta (with its coronary arteries attached) and the pulmonary artery. Using profound hypothermia, optical magnification, and microsurgical techniques, the aortic root is dissected below the coronary arteries and transected in a scalloped manner, carefully avoiding the valve commissures. Switching of the great vessels is then readily accomplished. Defibrillation was achieved in eight such trials in the newborn pig. Obviously, creating such a model of TGA in the animal is not identical to correction of this anomaly in an actual clinical situation, but it demonstrates well the technical aspects of aortic root dissection. We hope it may enable creation of a living experimental model of TGA with an atrial septa1 defect. It may even be possible to switch the vessels at the level of the ventricular conus. 4. Additional direct approaches are offered by simple switching of the pulmonary artery and aorta, with detachment of the coronary arteries at the ostia together with a rim of aortic tissue and anastomosis of these vessels and the aortic rim onto the proximal ascending aorta at its new site. Appropriate trimming of the valve apparatus and switched aorta and pulmonary artery is possible. We have successfully performed this operation in small animals over a period of one hour. From our studies and analysis of 58 hearts with complete TGA supplied by Dr. Maurice Lev s laboratory at the Hektoen Institute for Medical Research, reimplantation of the subcoronary aorta or both coronary arteries appeared possible in 26, probable in 21 (one of two coronary arteries would stretch more than 2 mm. to reach the proposed new site), and not possible in 11. Furthermore, for those patients in whom direct subcoronary switching or switching with reimplantation is not feasible due to the anatomical positions of the coronary ostia, other procedures might be considered. 5. For example, if both coronary ostia are very near each other, a cuff of aorta including both ostia could be reflected or detached and incorporated by fine suture technique onto the aorta in its new position. 6. Another modification, by Yacoub,* involves using a segment of the transposed aorta to incorporate the coronary artery flow into its new site. If the anatomical arrangement of the coronary ostia does not permit primary shifting into a new site, alternatives of the basic principle may still be available. 7. The subclavian artery, either singly or on both sides, may be anastomosed directly to the detached cuff of aorta around the coronary ostia following switching of the pulmonary artery and aorta. Anastomosis, if performed with optical assistance, fine suture material, and appropriate instruments, is quite feasible in 10-pound animals. On the question of growth and adequacy of coronary flow, our own experiments in calves *M. H. Yacouh, M.B.B.S., Harefield Hospital, London. Personal communication, VOL. 16, NO. 5, NOVEMBER,

5 ANAGNOSTOPOULOS ET AL. indicate that the left side of the heart can be totally supplied by two internal mammary artery grafts or one carotid graft; these animals and grafts have grown concomitantly, without congestive failure, from an average 120 to an average 1,300 pounds. This approach has already been proposed for the treatment of anomalous left coronary artery arising from the pulmonary artery [2]. 8. Alternatively, a segment of the subclavian artery can be sutured distally to the ascending aorta and proximally to the coronary artery aortic cuffs, a variation of procedure 7. C o n c 1 us i o ns The spectrum of anatomical variations of the coronary arteries in TGA [4, 171 may be therapeutically approached by the above-proposed techniques used either singly or in combination. It appears that technical considerations, although obviously important, should no longer be outright determining factors, since we now have among our resources modern and powerful tools that make a new and rational approach possible. These resources include the successful application of hypothermic operation in the newborn with TGA (Stansel"), the application of microsurgery such as is used in arterial reconstruction of the digits and hand as well as in skin graft anastomosis [9], optical assistance in microvascular surgery [ 181, and the experience of increased patency rates of arterial-to-coronary artery grafts [3, 6, 71. The ideal operation for TGA in the near future may prove to be the most direct operation. Perhaps the first patients for such a procedure should be those with TGA and ventricular septa1 defect in whom the left ventricular systolic pressures remain at systemic levels beyond the newborn stage. Eventually, and following encouraging results, direct operation may become the treatment of choice in the immediate newborn period for all types of TGA. The time has surely come for creative new action in this direction. As Shakespeare pointed out: References Diseases desperate grown By desperate appliance are relieved Or not at all. Hamlet, act 4, scene 3 1. Anagnostopoulos, C. E. A proposed new technique f.or correction of transposition of the great arteries. Ann. Thornc. Surg. 15:565, *H. C. Stanwl, Jr., M.D., Yale IJnivcrsity 'khool of Mrditine. Personal cornmimication, THE ANiVA1.S OF THORACIC SURGERY

6 Rational Operation for Transposition 2. Apley, J., Horton, R. E., and Wilson, M. G. The possible role of surgery in the treatment of anomalous left coronary artery. Thorax 12:28, Edwards, W. S., Lewis, C. E., Blakeley, W. R., and Napolitano, L. Coronary artery bypass with internal mammary and splenic artery grafts. Ann. Thorac. Surg. 15:35, Elliott, L. P., Amplatz, K., and Edwards, J. E. Coronary arterial patterns in transposition complexes: Anatomic and angiographic studies. Am. J. Cardiol. 17:362, El-Said, G., Mullins, C. E., Nihill, M. R., Hallman, G. L., Cooley, D. A., and McNamara, D. G. Changes after Mustard s operation for transposition of the great arteries (abstract). Am. J. Cardiol. 31:129, Green, G. E. Rate of blood flow from the internal mammary artery. Surgery 70:809, Green, G. E., Stertzer, S. H., Gordon, R. B., and Tice, D. A. Anastomosis of the internal mammary artery to the distal left anterior descending coronary artery. Circulation 41 (Suppl. II):79, Idriss, F. S., Goldstein, I. R., Grana, L., French, D., and Potts, W. J. A new technique for complete correction of transposition of the great vessels: An experimental study with a preliminary clinical report. Circulation 24:5, Jacobson, J. H., 11. Microsurgery. Curr. Probl. Surg., February, McGoon, D. C. Surgery for transposition of the great arteries (editorial). Circulation 45: 1147, McGoon, D. C. Surgical Management of the Transposition Complexes. Presented at the 2nd Annual Conference of the American College of Cardiology, San Francisco, Calif., February, Morgan, J. R., Miller, B. L., Daicoff, G. R., and Andrews, E. J. Hemodynamic and angiographic evaluation after Mustard procedure for transposition of the great arteries. J. Thorac. Cardiouasc. Surg. 64:878, Nadas, A. S., and Fyler, D. C. Pediatric Cardiology (3d ed.). Philadelphia: Saunders, P Parisi, L., and Fyler, D. C. Management of transp.osition of the great arteries in New England (abstract). Am. J. Cardiol. 31:151, Plauth, W. H., Nadas, A. S., Bernhard, W. F., and Fyler, D. C. Changing hemodynamics in patients with transposition of the great arteries. Circulation 42: 131, Rodriguez-Fernandez, H. L., Kelly, D. T., Collado, A., Haller, A., Krovetz, L. G., and Rower, R. D. Hemodynamic data and angiographic findings after Mustard repair for complete transposition of the great arteries. Circulation 46:799, , Shaher, R. M., and Puddu, G. C. Coronary arterial anatomy in complete transposition of the great vessels. Am..J. Cardiol. 17:355, Spencer, F. C. Binocular loupes (microtelescopes) for coronary artery surgery. J. Thorac. Cardiouasc. Surg. 62: 163, Stark, J., Tynan, M. J., Ashcraft, K. W., Aberdeen, E., and Waterston, D. J. Obstruction of pulmonary veins and superior vena cava after Mustard operation for transposition of the great arteries (abstract). Circulation 43 (Suppl. 11):91, Tynan, M., and Aberdeen, E. Tricuspid incompetence following the Mustard operation for transposition of the great arteries (abstract). Circulation 43 (Suppl. II):92, Waldo, A. L., Kron,grad, E., B,owman, F. O., Kaiser, G. A., Husson, G. S., and Malm, J. R. Electrophysiological considerations during total repair of transposition of the great vessels (abstract). Circulation 40 (Suppl. II):34, VOL. 16, NO. 5, NOVEMBER,