Ross Procedure With Enlargement Annuloplasty

Transcription

1 Ross Procedure With Enlargement Annuloplasty Willem Daenen, Stefan0 Conte, Benedict Eyskens, and Marc Gewillig The surgical relief of complex multilevel left-ventricular autograft,14 because we believe the pulmonary autooutflow tract (LVOT) obstruction remains a challenging graft is superior to others in the aortic p~sition, -~~ and problem. Several surgeries, adapted to each specific because it provides growth capacity for small chilcondition, have been proposed. Diffuse (tunnel) subval- dren. l8 vular stenosis with normal aortic valve and annulus can This report describes the surgical technique of this be relieved by myectomy with or without patch enlarge- operation that consists of a Ross procedure with root ment of the interventricular septum., Several aggres- replacement and enlargement of the aortic annulus and sive surgical procedures have been proposed to treat LVOT. The midterm results of a series of 16 patients those cases in which the aortic valve is part of the LVOT who underwent this approach were recently pubobstruction. Aortoventriculoplasty (AVP), introduced 1i~hed.l~ by Konno et al,3 and aortic root replacement proposed by Ross, ~ are certainly more satisfactory than the Patient History placement of a left ventricular apico-aortic cond~it.~*~ Radical procedures with aortic valve replacement appear to be more appropriate, but have the well-known disadvantages of tissue degeneration (bioprostheses) and thromboembolic phenomena (mechanical-valve prostheses).8- When the LVOT obstruction extends below the level of the subvalvular apparatus of the mitral valve, even more radical approaches are necessary. McKowen et all3 combined the concept of the AVP with the use of allografts in the surgery called extended aortic root replacement. We combined the concepts of the extended aortic root replacement with the use of a pulmonary Eleven patients underwent a Ross operation with enlargement of the LVOT after one or more attempts to resect a severe subvalvular aortic stenosis of tunnel type. In the other 5 patients, this procedure was attempted because of the increasing pressure gradient over an outgrown aortic-valve prosthesis. The patients ages at operation ranged from 2.5 to 28 years. The mean preoperative gradient was 98 mm Hg in the group with subvalvular aortic stenosis and 80 mm Hg in the group operated for an outgrown aortic prosthesis. Preoperatively, 3 patients presented signs of congestive heart failure. 318 Operative Techniques in Cardiac & Thoracic Surgery, Vol2, No 4 (November), 1997: pp

2 ROSS PROCEDURE WITH LVOT ENLARGEMENT 319 SURGICAL TECHNIQUE 1 Cardiopulmonary bypass is instituted using one aortic and one rightatrial cannula. The patient is cqoled to 20 C. After aortic cross-clamping, the aorta is transected 1 cm distal to the aortic commissures (dotted line, ---). Cristalloid cardioplegia is delivered through two separate coronary cannulas, until a septa1 temperature of 10 C is reached. Topical cooling with sludged ice is added to avoid myocardial rewarming. An insulation pad is used to protect the phrenic nerve from cold injury.

3 320 DAENEN ET AL 2 After confirmation of the diagnosis, the aortic valve is removed and the LVOT is sized with Hegar dilators. Excessive fibrous tissue at the subvalvular level is resected without entering the interventricular septum, especially in the region of the conduction mechanism. The two coronary ostia are excised from the aorta with a generous button of aortic wall. The coronary arteries are mobilized to allow proper excision of the buttons. The proximal part of the ascending aorta is then resected, leaving the annulus in place. The pulmonary artery is then transected at the level of the bifurcation (dotted line in 1) with a slight oblique cut up to the origin of the left pulmonary artery. The pulmonary valve is inspected before the decision is made to proceed with the Ross procedure. Small commissural fenestrations and an occasional bicuspid valve are accepted on the condition that preoperative color Doppler echocardiography showed only trivial regurgitation. The posterior wau of the main pulmonary artery is completely separated from the roof of the left atrium and the left main coronary artery, which is probed to allow better identification. The dissection is performed downward, using the electrocautery, until muscular tissue is identified at the base of the pulmonary valve ring.

4 ROSS PROCEDURE WITH LVOT ENLARGEMENT The right ventricular infundibulum is opened transversely 5 to 6 mm from the pulmonary valve annulus, which is identified by a probe placed through the pulmonary valve. The excision of the pulmonary root is completed in a lateral and a dorsal plane, taking care to avoid large septa1 arteries (S, and S2), which can always be identified. At this point, the dissection has to stay in the same horizontal plane as the collateral arteries. I

5 322 DAENEN ET AL 4 (A) The narrowed aortic annulus and the interventricular septum are incised starting slightly anterior of the commissure, between the right and left aortic cusp. This incision is continued leftward into the infundibular septum to avoid the conduction mechanism.

6 ROSS PROCEDURE WITH LVOT ENLARGEMENT (continued) (B) The length of the incision depends on the severity of the LVOT obstruction and the size of the pulmonary autograft annulus. The margins of the septa1 incision are bevelled off at the left-ventricular site to further widen the LVOT. If aberrant tendons inserting in the interventricular septum are present, these should be resected at this stage.

7 324 DAENEN ET AL 5 The left-ventricle outflow tract is widened with a triangular Dacron or a bovine pericardial patch, using a running 3-0 monofilament suture starting from the riglit ventricular site and without the use of Teflon (DuPont, Wilmington, DE) pledgets. Then the the pulmonary autograft is anastomosed to this enlarged aortic annulus using a 3-0 running monofilament suture. The sutures are placed just proximal to the edge of the pulmonary valve insertion, and progress in a horizontal plane similar to those placed at the site of the aortic annulus. This suture-line is located into the aortic annulus and does not incorporate the remnants of the aortic wall.

8 ROSS PROCEDIJRE WITH LVOT ENLARGEMENT Anteriorly the autograft is sutured to the patch. The autograft is oriented by lining up one of the commissures of the autograft with the commissure between the previously resected left and right aortic sinuses. As long as this orientation is respected, no problems will be encountered in the localization of the coronary implantation sites.

9 326 DAEhEN ET AL 7 The annular anastomosis is reinforced with a second 3-0 running suture approximating the external remnants of the aortic wall and the muscle bar of the autograft. An autologous pericardial strip is incorporated in this suture line. This second suture line is only indicated in cases of adult-sized annulus. The purpose of this is to prevent possible annular dilatation, and to achieve better hemostasis. The coronary arteries are implanted in the autograft with a 6-0 running polypropylene suture. Usually we start with the left coronary anastomosis, making a longitudinal slit in the autograft wall. The anastomosis of the right coronary artery is always placed at a more distal level in the autograft to avoid kinking after removal of the aortic cross-clamp.

10 ROSS PROCEDCJRE WITH LVOT ENLARGEMENT A long, cryopreserved pulmonary homograft is used to reconstruct the right-ventricular outflow tract (RVOT). We start the anastomosis at the site of the pulmonary bifurcation, using a 5-0 monofilament running suture. This anastomosis should he as large as possible. Therefore, the homograft is trimmed very distally into the branching of the two main pulmonary arteries. The ventricular anastomosis starts at the left of the conal prelevation site and progresses towards the base of the autograft. These suture lines should not go too deep in the septum to avoid injury to a septal coronary artery. The right part of the anastomosis runs over the base of the autograft to anteriorly meet the infundibulum. Because the RVOT is also widened by the septal patch, an oversized pulmonary homograft should he used. Once again, we emphasize the use of a long homograft to avoid tension and flattening of the graft, which might cause valvular incompetence.

11 328 DAENEN ET AL 9 Finally the distal anastomosis between autograft and aorta is made. The diameter of the distal native aorta is eventually reduced or enlarged (see inset) with a patch of native aortic wall or pericardium. All the anastomoses are sealed with fibrin glue. Before closing the chest, the pericardium is closed with a Gore-Tex (W.L. Gore, Newark, DE) surgical membrane to facilitate later sternal reentry because we realize that homograft replacement might be necessary in the future.

12 ROSS PROCEDURE WITH LVOT ENLARGEMENT 329 COMMENTS The effectiveness of this operation was proved by a marked increase in the minimal LVOT diameter, measured by echocardiography on the first 9 patients operated on because of redo-subvalvular aortic stenosis. The mean minimal LVOT diameter expressed in percentages of the normal body surface area increased from 51% preoperatively to 103% after repair.19 Later, the indication for this procedure was extended to those patients experiencing excessive gradients over outgrown aortic valvular prostheses. A classical root replacement is, in our opinion, not radical enough because of the small valve annulus and an often impressive septal hypertrophy with secondary dynamic obstruction. Myocardial protection is of paramount importance in this complex operation not only because of the long cross-clamping time (145 minutes in this series), but also because of the important myocardial hypertrophy and fibrosis present in most of these patients. The reconstruction of the RVOT can be done on a beating heart to shorten this long cross-clamping time. However, we believe that this reconstruction deserves meticolous attention, because it is the Achilles' heel of the Ross operation. This is particularly important for the anastomosis between the homograft and the pulmonaryartery bifurcation. The good exposure resulting from the still transected aorta and the dry operation field are of great help in performing this anastomosis free from obstruction. The same applies to the right-ventricular anatomosis, in which damage to important septal coronary arteries are more easily avoided if the aorta is still cross-clamped. One patient had to be reoperated on because of progressive autograft dilatation and massive aortic regurgitation 4 years after the operation, even though autograft function was perfect in the early postoperative period. Because of this experience, we advocate reinforcement of the proximal aortic anastomosis in adult-sized patients. Some investigators harvest a triangular flap of infundibular free wall together with the autograft and use this flap to enlarge the septum.'o We do not favor this approach because we have some doubts about the viability and the strength of long-term septal reconstruction. Furthermore, the function of the right ventricle and the homograft might be jeopardized by the patch that is used to fill the harvesting site. In some instances, aberrant left-ventricular tendons inserting in the interventricular septum are recognized once one has broad access to the left ventricular cavity. These tendons should be resected because they might play a role in chronic damage of the autograft by turbulence and in recurrence of the subvalvular stenosis.21 Conclusion The enlargement of complex LVOT is possible without compromising the outcome of patients undergoing the Ross procedure by using aortic root replacement with a pulmonary autograft. This operation is very effective for young patients because growth capacity has been documented. The reinforcement of the autograft annulus is strongly advocated in adult-sized patients. The surgical complexity of this operation should not discourage its use in the management of complex LVOT obstruction REFERENCES Vouhe PR, Ponlain H, Bloch G, et al: Aortosrptal approach for optimal resection of diffuse subvalvular aortir stenosis. J Thorac Cardiovasc Surg 87: ,1984 DeLeon SY, Ilbawi MN, Roberson DA, et al: Conal enlargement for diffuse subaortic stenosis. J Thorac Cardiovasr Surg 102: , 1991 Konno S, Imai Y, Iida Y, et al: A new method for prosthetic valve replacement in rongenital aortic stenosis associated with hypoplasia of the aortic valve ring. J Thorac Cardiovasc Surg 70: ,1975 Ross DN: Replacement of aortic and mitral valves with a pulmonary autograft. Lancet 2: , 1967 Gerosa G, McKay R, Ross DN: Replacement of the aortir valve or root with a pulmonary autograft in children. Ann Thorac Surg 51: , 1991 Brown JW, Girod DA, Hurwitz RA, et al: Apicoaortic valved conduits for complex left ventricular outflow obstruction: technical considerations and current status. Ann Thorac Surg 38: ,1984 Di Donato RM, Danielson GK, McGoon DC, et al: Left ventricularaortic conduits in pediatric patients. J Thorac Cardiovasc Surg 88:82-91,1984 de Vivie ER, Koncz J, Rupprath G, et al: Aortoventriculoplasty for different types of left ventricular outflow obstructions. J Cardiovasr Surg 23:6-11, 1982 Koul BL, Henze A, Bjork VO: Aortoventriculoplasty ad modum Konno. Experience with five cases. Scand J Thorac Cardiovasc Surg ,1984 Misbach GA, Turley K, Ullyot DJ, et al: Left ventricular outflow enlargement by the Konno procedure. J Thorac Cardiovasc Surg 84: ,1982 Fleming WH, Sarafian LB: Aortic valve replacement with concomitant aortoventriculoplasty in children and young adults. Ann Thorac Surg 43: , 1987 McIntyre B, Guyton RA, Jones EL, et al: Reoperation for prosthetic valve degeneration after Konno aortoventriculoplasty. J Thorac Cardiovasc Surg 91: , 1986 McKowen RL, Campbell DN, Woelfel GF, et al: Extended aortic root replacement with aortic allografts. J Thorar Cardiovasc Surg 93: ,1987 Daenen W, Gewillig M: Extended Aortic Root Replacement with Pulmonary Autografts. Eur J Cardiothorac Surg 7:42-46, 1993 Gerosa G, McKay R, Davies J, et al: Comparison of the aortic homograft and the pulmonary autograft for aortir valve or root replacement in children. J Thorac Cardiovasc Surg 2:Sl-61,1991 Matsuki 0, Okita Y, Almeida RS, et al: Two derades' experience with aortic valve replacement with pulmonary autograft. J Thorac Cardiovasc Surg 95: ,1988 Randolph JD, Toal K, Stelzer P, et al: Aortic valve and left ventricular outflow tract replacement using allograft and autograft valves: A preliminary report. Ann Thorac Surg 48: ,1989 Elkins CE, Knott-Graig CJ, Ward KE, et al: Pulmonary autograft in children: Realized growth potential. Ann Thorac Snrg 57: , 1994

13 330 DAENEN ET AL 19. Diirnen WJ: Managrmeut of romplex LVOTO with pulmonary autograft. Seminars Thorac Carcliovasc Surg 8: , Reddy VM, Rajasinghe HA, Trite1 DF, et al: Aortoventriculoplasty using From the Departments of Cardiac Surgery and Pediatric Cardiology, Gasthuis- University Hospita17 Leuverl,,~llnl~~,lary autograft: The * ~ R ~,,)rocedure. ~ ~. J K ~ ~ ~ h cardio. ~ ~ ~ ~ Address ~ reprint ~ : requests to Willem Daenen, MD, Gasthuisberg University vaw Surg 111: , GewiIlig M, Daenen W, Uumoulin M, et al: Rheologic genesis of disrrete Hospital, Hrrestraat 49, B-3000 Leuven, Belgium. Copyright by W.B. Saunders Company suhaortic struosis: A Doppler rchorardiographir study. J Am CoU /97/ $5.00/0 Ca rcliol I9: