MMCTS
(September 15, 2008). doi:10.1510/mmcts.2008.003160
Copyright © 2008 European Association for Cardio-thoracic Surgery
Procedure
Ross-Konno operation in children
Viktor Hra ka*,
Joachim Photiadis,
Rudolf Poruban,
Peter Murin and
Boulos Asfour
Department of Pediatric Cardiac Surgery, German Pediatric Heart Center, Asklepios Clinic Sankt Augustin, Arnold Janssen Str. 29, 53757 Sankt Augustin, Germany
* Corresponding author: Tel.: +49-2241-249603; fax: +49-2241-249602. v.hraska{at}asklepios.com
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Summary
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The Ross-Konno procedure is an excellent technique for the treatment of complex multilevel left ventricular outflow tract obstruction with severe annular hypoplasia and a dysplastic aortic valve. The operation can be performed earlier in life, thus avoiding repeated surgical reinterventions, which may provide only short-term palliation and potentially exacerbate ventricular function. The Ross-Konno procedure increases our therapeutic choices for neonates or infants with critical aortic stenosis, who show unacceptable results following open valvotomy or balloon valvotomy. The pulmonary autograft demonstrates durability without the likelihood of developing aortic stenosis or progressive dilatation and a low incidence of developing aortic insufficiency. Despite the technically demanding nature of the operation, the Ross-Konno procedure is the method of choice for the multilevel type of left ventricle outflow tract obstruction, especially in newborns and infants.
Key Words: Aortic valve replacement • Congenital heart disease • Multilevel left ventricle outflow tract obstruction
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Introduction
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Complex, multilevel left ventricular outflow tract obstruction (LVOTO) consists of a combination of a hypoplastic aortic annulus with or without a dysplastic aortic valve and diffuse subaortic narrowing, as frequently seen in Shone's syndrome, after primary repair of an interrupted aortic arch (IAA) or in congenital aortic valve stenosis. Initial palliation aims to relieve the critical level of obstruction. This may involve open/balloon aortic valvotomy, and/or subaortic membrane and muscle resection [1, 2]. Often this initial approach might avoid a more extensive operation in the first days of life, thus achieving clinical improvement with some degree of residual stenosis or insufficiency. However, the recurrence rate of severe LVOTO and progression of acquired aortic regurgitation is high. If relief of multilevel LVOTO and aortic valve replacement is indicated, the Ross-Konno operation should be considered as a method of choice.
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Ross-Konno operation with resection of endocardial fibroelastosis in infants
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In children, a technique of complete root replacement with anterior aortoventriculoplasty is used [3]. The standard technique of cardiopulmonary bypass, including bicaval cannulation and moderate hypothermia are used. Myocardial protection is preferentially provided by retrograde cardioplegia. A left ventricular vent is inserted through the entrance of the right pulmonary veins (Video 1).
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Video 1 Extensive dissection and mobilization of the ascending aorta, the pulmonary trunk and both pulmonary arteries are carried out. The ductal tissue is ligated and transected to improve mobility of the pulmonary arteries.
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After aortic cross-clamping, the aorta is partially transected and the feasibility of valve repair is assessed. The main pulmonary artery is transected just proximal to the bifurcation of the PA. In the case of severe abnormalities or bicuspid anatomy, one should consider abandoning the Ross-Konno operation and perform the Konno operation with a mechanical valve (Video 2).
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Video 2 The aorta is transected at the level of the sinotubular junction. The pulmonary valve is inspected to ensure no abnormality exists.
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After complete transection of the aorta, the right and left coronary buttons are formed and dissected for maximal mobilization (Videos 3, 4).
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Video 3 The coronary arteries are explanted, with large coronary buttons comprising almost the entire wall of the sinus of Valsalva. Extensive mobilization of both coronaries is performed to facilitate transfer. Dissection of the left coronary artery.
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Video 4 Dissection of the right coronary artery.
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The aortic cusps and sinus wall are removed, leaving an approximately 3–5 mm cuff of the aortic wall annulus in place (Video 5).
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Video 5 Resection of the aortic cusps.
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The pulmonary autograft is harvested, along with an extension of the infundibular free wall muscle which is attached to it. This extra tissue is used for patching the ventriculoplasty incision (Video 6).
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Video 6 A right-angled clamp is used to identify the opening on the right ventricle anterior wall, staying away from the valve. The incision is extended in both directions leaving an approximately 10 mm of the anterior free wall of the right ventricle attached and an additional 3–5 mm muscular cuff of tissue around the rest of the pulmonary valve.
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Great care is taken to avoid injury to the left coronary artery, the pulmonary artery valves, and septal perforator of the left coronary artery (Video 7).
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Video 7 A shallower incision of the endocardial surface is made at the septum with fine scissors. Subsequently, the dissection plane is developing with the scissors angled to prevent deep dissection into the interventricular septum and injury to the first septal branch of the left anterior descending artery.
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After harvesting the pulmonary valve, cardioplegia is delivered and any bleeding points from the area of previous dissection are controlled, either by diathermy or by over-sewing with a shallow suture (Video 8).
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Video 8 The bleeding points are controlled.
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The interventricular septum is incised to the left of the right coronary artery. The length of the incision depends on the morphology of the obstruction. If only an annular enlargement is necessary, the septal incision is limited, extending about 5–10 mm into the septum. In patients with long-segment subaortic stenosis, the septal incision is extended beyond the obstruction (Video 9).
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Video 9 The aortic annulus is enlarged by incising the interventricular septum between the left and right commissures.
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Resection of any endocardial fibroelastosis or ventricular myectomy is performed, if necessary. The goal is to remove any fibrous tissue which could obstruct the left ventricular outflow tract and limit the movement of left ventricle cavity (Video 10).
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Video 10 A combination of blunt and sharp dissection is used to enucleate the membrane of the underlying myocardium. The location of the conduction tissue near the membranous septum should be identified and any deep, sharp dissection must be avoided. A blunt dissection is preferable. The effectiveness of the resection is assessed.
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The pulmonary autograft is implanted in the left ventricular outflow tract (LVOT) using a running suture technique. Natural alignment of autograft is preferable. The left semilunar cusp of pulmonary autograft should occupy area of previous left coronary cusp. Therefore, the anterior semilunar cusp of pulmonary valve (autograft) is orientated anteriorly and the anterior lip of the retained infundibular free wall is used to patch triangular area of incised interventricular septum (Video 11).
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Video 11 The pulmonary autograft is seated with the infundibular muscle extension fitting into the Konno incision in the interventricular septum. Note that additional myectomy was necessary to accommodate the pulmonary autograft.
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The suture line is subannular so that the autograft is plugged into the left ventricular outflow tract, thus having the fibromuscular support of the outflow tract (Video 12).
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Video 12 The autograft is sutured to the base of the aortic annulus using a continuous suture.
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The second running adventitial suture over the remnant of the aortic wall reinforces the first one and decreases the risk of inaccessible bleeding, especially from the posterior aspect of the anastomosis. It is important to reinforce the patching of ventriculoplasty incision by infundibular free wall muscle with pledgeted interrupted mattress sutures to minimize the risk of bleeding or aneurysm formation (Video 13).
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Video 13 The infundibular muscle extension is reinforced with non-absorbable, interrupted, pledgeted mattress sutures.
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The left coronary artery button is implanted into the circular opening made in the pulmonary artery wall, avoiding rotation, tension or kinking (Video 14).
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Video 14 Reimplantation of the left coronary artery into the neoaortic trunk.
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The neoaortic reconstruction is completed by proximal anastomosis with the ascending aorta using a continuous suture. After completing the distal anastomosis, the neoaortic root is expanded with a dose of cardioplegia and the appropriate position for implantation of the right coronary artery is determined. A circular opening is made in the pulmonary artery wall, staying away from the valve commissure, and the coronary is implanted (Video 15).
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Video 15 Reimplantation of the right coronary artery into the neoaortic trunk.
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The right ventricular outflow tract is reconstructed with the homograft. The homograft is sutured directly to the right ventricular infundibular muscle without the use of any additional patching material (Videos 16, 17).
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Video 16 The distal anastomosis is carried out first, placing the sinuses of the homograft (in this case an aortic homograft was used) into the appropriate position. A mobile pulmonary artery bifurcation facilitates construction of this anastomosis.
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Video 17 The posterior aspect of the proximal suture line between the right ventricular outflow tract and the homograft is performed by placing shallow bites to avoid the coronaries. Anteriorly, the suture line takes the full thickness of the muscle of the right ventricular outflow tract.
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An ECHO should be routinely performed after the patient has been weaned from bypass (Video 18).
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Video 18 Final result of operation. No LVOTO, trivial neoaortic regurgitation.
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Results
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The Ross-Konno procedure can be accomplished with a mortality of <5% and a low morbidity (Table 1). Early complications are especially related to malignant arrhythmias (non-sustained ventricular tachycardia, non-sustained supraventricular tachycardia, etc.) [4,5,6]. The incidence of complete heart block varies from 0% to 6%. The freedom from autograft reoperation is above 90% at 10 years of follow-up [5, 7, 8]. The freedom from homograft reoperation is between 70% and 94% at 5 years, being less favorable for small children due to earlier homograft failure [8]. The choice of conduit appears to impact the need for replacement. The aortic homograft rather than pulmonary homograft and smaller homograft size are factors adversely affecting homograft longevity. The policy is to place the largest pulmonary homograft possible at the time of procedure [9].
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Discussion
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The Ross-Konno procedure is an excellent technique for the treatment of complex, multilevel left ventricular outflow tract obstruction, even in neonates and infants with significant annular and subannular hypoplasia. Recently, the Ross-Konno procedure has found application in patients with an interrupted aortic arch as the initial procedure or after primary repair in patients with a severely restricted subaortic area, hypoplastic aortic annulus and bicuspid valve [5, 6, 10]. The Ross-Konno procedure increases our therapeutic choices for neonates or infants with critical aortic stenosis who show unacceptable results following open valvotomy or balloon valvotomy [5]. Some newborns with critical aortic stenosis, a hypoplastic aortic annulus and significant endocardial fibroelastosis can be effectively treated with the Ross-Konno procedure and resection of endocardial fibroelastosis, thus avoiding single ventricular palliation. The Ross-Konno procedure allows easy access to the left ventricular myocardium for resection of endocardial fibroelastosis, normalizing the left ventricular outflow tract and the long axis of the left ventricle [3]. The Ross-Konno procedure can be performed earlier in life, thus avoiding repeated surgical reinterventions, which may provide only short-term palliation and potentially exacerbate ventricular function [4]. There are disadvantages of the Ross-Konno procedure as well. The nature of the operation places two valves at risk for single valve disease. However, many pediatric patients are not candidates for a Konno operation because of anatomic considerations and the lack of readily available, appropriately sized prostheses [11].
Particularly in the growing pediatric patient the need for pulmonary conduit replacement is high. Replacement of a pulmonary conduit is, however, less difficult than repeated aortic root replacement. Other concerns regarding the use of the Ross-Konno procedure in children include the uncertain long-term outcome of the pulmonary autograft in the aortic position. The pulmonary autograft demonstrates durability without developing aortic stenosis or progressive dilatation, and there is a low incidence of aortic insufficiency development. Enlargement of the aortic annulus parallels somatic growth in the majority of cases [8, 12]. Patching the ventriculoplasty incision by infundibular free wall muscle optimizes the geometry of neoaortic root and LVOT. It allows regular, proportional growth of neoaortic root. The ventriculoplasty incision could be reconstructed by a separate prosthetic patch as well. The drawbacks are, increased complexity of reconstruction of LVOT and unpredictable growth of anterior segment of neoaortic root ‘immobilized’ by rigid patch.
It is unclear whether the use of the Ross-Konno procedure at an earlier age alters the natural history of complex left ventricular outflow tract disease. It is also not known whether the risk of late reoperation on the neoaortic valve is higher if performed in the neonate, infant, or child due to aortic root sinus dilation and valve distortion over time. Based on experience from arterial switch operations for transposition of the great arteries, the neonatal pulmonary valve might be able to adapt rapidly to the aortic position. Long-term changes in left ventricular mechanics await further study. Despite the technically demanding nature of the operation, the Ross-Konno procedure is the method of choice for the multilevel type of left ventricle outflow tract obstruction, especially in newborns and infants [4, 5, 8].
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References
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- Reddy VM, Rajasinghe HA, Teitel DF, Haas GS, Hanley FL. Aortoventriculoplasty with the pulmonary autograft: the ‘Ross-Konno’ procedure. J Thorac Cardiovasc Surg 1996;111:158–165; discussion 165–167.[Abstract/Free Full Text]
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Summary
Introduction