World Journal for Pediatric and Congenital Heart Surgery http://pch.sagepub.com/
Aortic Cusp Extension for Surgical Correction of Rheumatic Aortic Valve Insufficiency in Children Afksendiyos Kalangos and Patrick O. Myers World Journal for Pediatric and Congenital Heart Surgery 2013 4: 385 DOI: 10.1177/2150135113498785 The online version of this article can be found at: http://pch.sagepub.com/content/4/4/385
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Review Article
Aortic Cusp Extension for Surgical Correction of Rheumatic Aortic Valve Insufficiency in Children
World Journal for Pediatric and Congenital Heart Surgery 4(4) 385-391 ª The Author(s) 2013 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/2150135113498785 pch.sagepub.com
Afksendiyos Kalangos, MD, PhD1, and Patrick O. Myers, MD1
Abstract Surgical management of aortic insufficiency in the young is problematic because of the lack of an ideal valve substitute. Potential advantages of aortic valve repair include low incidences of thromboembolism and endocarditis, avoiding conduit replacements, the maintenance of growth potential, and improved quality of life. Aortic valve repair is still far from fulfilling the three key factors that have allowed the phenomenal development of mitral valve repair (standardization, reproducibility, and stable long-term results); however, techniques of aortic valve repair have been refined, and subsets of patients amenable to repair have been identified. We have focused on the oldest technique of aortic valve repair, cusp extension, focusing on children with rheumatic aortic insufficiency. Among 77 children operated from 2003 to 2007, there was one early death from ventricular failure and one late death from sudden cardiac arrhythmia. During a mean follow-up of 12.8 + 5.9 years, there were 16 (20.5%) reoperations on the aortic valve, at a median of 3.4 years (range, 2 months to 18.3 years) from repair. Freedom from aortic valve reoperation was 96.2% + 2.2% at 1 year, 94.9% + 2.5% at 2 years, 88.5% + 3.6% at 5 years, 81.7% + 4.4% at 10 years, 79.7% + 4.8% at 15 years, and 76.2% + 5.7% at 20 years. Although aortic cusp extension is technically more demanding, it remains particularly more suitable in the context of evolving rheumatic aortic insufficiency in children with a small aortic annulus as a bridge surgical approach to late aortic valve replacement with a larger valvular prosthesis. Keywords aortic valve repair, congenital heart surgery, heart valve, rheumatic Submitted April 26, 2013; Accepted July 01, 2013. Presented at The Sixth World Congress of Paediatric Cardiology and Cardiac Surgery, Cape Town, South Africa; February 17-22, 2013.
Presented at the World Society for Pediatric and Congenital Heart Surgery Symposium on Surgery for Rheumatic Heart Disease at The Sixth World Congress of Paediatric Cardiology and Cardiac Surgery, Cape Town, South Africa; February 17-22 2013.
Introduction Significant limitations of prosthetic valve replacement in the young stimulated the development of valve repair techniques. Standardized, reproducible, and stable long-term results of mitra valve repair are three key factors that encouraged surgeons to apply this conservative approach on the aortic valve. Despite the fact that surgeons are currently far from fulfilling these three key factors in aortic valve repair, they have been able to refine the techniques of aortic valve repair with time and identify a subset of patients amenable to repair.
Rheumatic Aortic Valve Disease: Lesions and Mechanism of Aortic Valve Dysfunction The mitral and aortic valves are the most frequently affected heart valves by rheumatic heart disease, and surgery is usually
required within five to ten years after diagnosis. Progressive transformation of the inflammatory process into fibrosis over time is responsible for impairing valve function. In rheumatic aortic valve involvement, fibrosis increases the cuspal tissue thickness, retracts and sometimes elongates the free edge of one or more cusps, deforms them gradually, and subsequently predisposes them to calcification. In children, the mobility of the thickened and retracted cusps is somewhat preserved, the cusp involvement by fibrosis being attenuated, with a macroscopically thinned and normal appearance in some patients. Cusp prolapse caused by the elongation of the free edge of one or more aortic leaflets can be seen in 40% to 55% of the patients. The aortic annulus usually remains normal or minimally dilated in children. 1 Division of Cardiovascular Surgery, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland
Corresponding Author: Afksendiyos Kalangos, Division of Cardiovascular Surgery, Geneva University Hospitals and Faculty of Medicine, 4, Rue Gabrielle-Perret-Gentil, 1211 Geneva, Switzerland. Email: [email protected]
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In the majority of patients, the resulting dysfunction is central aortic insufficiency. However, in some patients, the central leak is associated with a varying degree of mild to moderate stenosis due to the inconsistent intensity of commissural fusion.
Aortic Cusp Extension as the Oldest of the Aortic Valve Repair Techniques The aim of aortic cusp extension is to correct the lack of coaptation between the aortic cusps resulting in aortic valve regurgitation, by establishing a new surface of coaptation by extending the cusps using different patch materials, up to the level of the sinotubular junction. With respect to the shape of the extension patch, the tendency has evolved over the past 30 years from a single-patch to a three-patch configuration.1-10 In none of these published series, the real dimensions of native aortic cusps had been taken into account in the tailoring process of the extension patches, probably due to the fact that in some of them, the cusps were either totally or partially excised by eliminating the thickened part of the cusps, leaving an equal height of the remaining tissue in each cusp before reconstruction. In the majority of patients with rheumatic aortic insufficiency, cusps have a varying degree of retraction and deformity, rendering them nonidentical to each other in terms of cusp height, length of free edge, and thickness. For precisely this reason, we have conceived a more geometric concept of cusp extension by reestablishing only the dimensions required to reconstruct three identical cusps in terms of height and cuspal free edge, by moving the new coaptation level up to the sinotubular junction. The choice of extension material is the second important point, which could potentially influence the durability of aortic valve repair over time. After the first attempts by Yacoub and Senning who utilized the dura mater and the fascia lata as patch material, respectively, promising mid-term clinical results have been reported by authors who used glutaraldehyde-treated bovine pericardium after partially excising aortic cusps.11-13 Interest was then focused on using autologous pericardium, probably triggered also by the rapid structural deterioration and primary tissue failure observed with heterograft bioprostheses and homograft valves in children. The literature concerning the use of fresh or glutaraldehydetreated autologous pericardium seems to be divided. Fresh autologous pericardium shows progressive retraction with gradual loss of pliability due to fibrous degenerative changes over time (Figure 1). Autologous pericardium treated in 0.62% glutaraldehyde-buffered solution for 30 minutes behaves like glutaraldehyde-treated heterologous pericardium in terms of calcification tendency.14 Shorter treatment (15 minutes) was proposed for slowing down the excessive fibrous tissue formation observed in the case of fresh autologous pericardium and the calcification observed in the case of glutaraldehyde treatment of longer duration.15 Although the promising experimental and clinical studies showed that the short glutaraldehyde-treated autologous pericardium does not calcify and shrink after implantation,14,16,17 Liao et al found that even short treatment may be enough to change the biologic identity of the autologous
Figure 1. Microscopic section of leaflet after cusp extension with fresh autologous pericardium (hematoxylin & eosin stain). The arrowhead denotes the junction between the native leaflet tissue (below), which is relatively thin and mobile, and the extension material (above), which has retracted and calcified.
pericardium, resulting in a ‘‘foreign body’’ reaction by the host, characterized by pericardial inflammation.14 In our series, the PhotoFix bovine pericardium (Cardiofix; Sorin Carbomedics, Milano, Italy), which uses dye-mediated photooxidation rather than chemical cross-linking of the collagen fibers, showed better durability than glutaraldehyde-treated bovine pericardium,18 although calcification in long term is not excluded (Figure 2). As the manufacturing of this material is currently discontinued, the search for the ideal patch material is still ongoing, and many groups have focused their attention on extracellular matrix (ECM) bioscaffolds in aortic valve repair. The ECM scaffolds that remain essentially unchanged from native ECM elicit a host response that promotes cell infiltration and rapid scaffold degradation, deposition of host-derived neomatrix, and constructive tissue remodeling with minimal scar tissue; this represents a fundamentally different scaffold material than ECM that has been chemically or otherwise modified.19 CorMatrix (CorMatrix, Roswell, Georgia) is a bioscaffold made from intestinal submucosa which has been approved by the US Food and Drug Administration for intracardiac repair.20 Based on the in vitro and in vivo animal studies, this bioscaffold was shown to be progressively replaced with autologous tissue from autologous tissue on the edge of the patch. The patch needs to be entirely encircled by autologous tissue (ie, implanted at the base of the leaflet rather than on the free edge) or colonization of the patch before biodegradation would not be
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387 theoretical advantage of being relatively stable and noncalcifing. Although used at other sites in the heart, the reported clinical experience in aortic valve repair with this material is limited to just 13 adult patients with a mean follow-up of 14.8 months,22 and there are no reports on cusp extension with this patch material in children. From a theoretical standpoint, PTFE is a durable monofilament plastic polymer that has unique characteristics, including flexibility, remarkable breaking strength, negative charge (like the native endothelium), and biostability.23 Larger mid- and long-term follow-up data and reports of its use in aortic valve repair in children are still pending, and this material may be at risk of calcification23 or late fracture.24
Aortic Cusp Extension Technique
Figure 2. PhotoFix pericardium cusp extension. A, PhotoFix pericardium cusp extension five years later. Surgical view of the repaired aortic valve (AV) in a patient requiring reoperation for mitral valve (MV) repair five years after PhotoFix (Sorin CarboMedics) cusp extension. The extensions were pliable, and presented no calcifications or retraction. Reproduced with permission from Myers et al.18 B, Leaflets 12 years after PhotoFix cusp extension, showing thickening and calcification.
complete. Its application in heart valve repair is relatively new, and there is a paucity of data available. Currently, there are no reported data available on the results of aortic valve with CorMatrix. In a retrospective study of 25 children with congenital mitral or tricuspid lesions who underwent leaflet patch augmentation with CorMatrix, the reoperation rate was similar to matched controls who had leaflet patch augmentation with glutaraldehyde-treated pericardium at 12-month follow-up, although the mechanism of failure tended to differ, with more patch retractions in the pericardium group.21 Expanded polytetrafluoroethylene (PTFE) has been proposed as a leaflet repair patch material. The PTFE has the
A large rectangular piece of anterior autologous pericardium is harvested and applied on a wet woven Dacron patch or a surgical wrap fabric with its mesothelial surface upward if the surgeon decides to use it as a fresh material. In this case, the Dacron patch or the piece of surgical wrap fabric serves as a template for sizing, trimming, and handling these template materials are not being necessary if the autologous pericardium is treated with glutaraldehyde. The loose fatty areolar tissue is removed by blunt dissection. After obtaining cardiac arrest by selective cardioplegia into both coronary ostia through a transverse aortotomy, the aortic valve is exposed with three stay sutures placed at the lower and upper flaps of the aortotomy. All aortic cusps are first inspected with particular regard to the valve morphology, commissural fusion, cusp prolapse, degree of retraction, cusp calcification, and appearance of the sinuses of Valsalva. The length of each cuspal free edge and height as well as the sinotubular junction and aortic annulus diameter are then measured. Subsequently, based on the measurements of each cusp, the shape of each pericardial patch is traced onto the template fabric or glutaraldehyde-treated pericardium (Figure 3A). In Figure 3B, the dimension B to D equals to the diameter of the sinotubular junction plus 15% of this diameter to account for eventual loss resulting from the progressive shrinkage of the fresh pericardium over time. In the case of glutaraldehyde-fixed autologous or heterologous pericardium, this 15% oversizing of the dimensions B to D is not necessary. The G to I equals to the length of the cuspal free edge. The height of both the commissural extensions (A-F and E-J) is equal to 3 mm. The C-H is designed according to the distance between the middle of each cusp’s axis and the level of sinotubular junction and oversized by approximately 2 mm to allow for suturing the patch on the cuspal free edge of each corresponding aortic cusp. The G to H equals to the length of the free edge of each corresponding aortic cusp. Suturing of the patches on the free edge of each corresponding aortic cusp starts at the midpoint of the cusp and goes up to both the opposite commissures using the two arms of the 5-0 monofilament suture material. These running sutures are finally brought out through the aortic wall between the native commissure and its above placed pericardial extension fixed on the aortic wall by two 5-0 monofilament mattress stitches tied outside the aorta. The running sutures of neighboring aortic
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Figure 3. Surgical technique of cusp extension. Reproduced with permission from Kalangos et al.22
cusps brought out through the commissural part of the aorta, as described previously, are tied together outside the aorta. The cusps are thinned, and a concomitant commissurotomy is performed if their mobility is restricted. The eventual occlusion of the coronary ostia by direct apposition of the patches to the wall of sinuses of Valsalva can be avoided by not exceeding the height of the extended cusps above the level of sinotubular junction as well as by not exceeding the length of each cusp free edge more than the diameter of the sinotubular junction in the case of glutaraldehyde-treated pericardium and plus 15% of this diameter in case of fresh autologous pericardium. Figure 3H shows that the shape of each of the three pericardial extensions is different, due to the variable intensity of retraction and deformity of each of the native aortic cusps.
Mid- and Long-term Results of Aortic Cusp Extension for the Surgical Management of Rheumatic Aortic Insufficiency We previously reviewed our mid-25 and long-term18 results of aortic cusp extension in children with rheumatic aortic insufficiency. From 2003 to 2007, 78 consecutive children underwent
aortic cusp extension for this indication. The material used for cusp extension was fresh autologous pericardium in 53 (68%) patients. In 25 (32%) patients, the pericardium was not deemed usable and an alternative, off-the-shelf pericardium was used, PhotoFix bovine pericardium (Cardiofix, Sorin CarboMedics) in 16 (21%) patients and glutaraldehyde-fixed bovine pericardium (St Jude Medical Inc, St Paul, Minnesota) in 9 (12%) patients when Cardiofix was discontinued. There was one early death from ventricular failure and one late death from sudden cardiac arrhythmia. During a mean follow-up of 12.8 + 5.9 years, there were 16 (20.5%) reoperations on the aortic valve, at a median of 3.4 years (range, 2 months to 18.3 years) from repair. There were ten reoperations in the fresh autologous pericardium group (18.9%), three in the bovine pericardium group (33.3%) and three in the PhotoFix group (18.8%, Fisher exact test, P ¼ .62). Freedom from aortic valve reoperation was 96.2% + 2.2% at 1 year, 94.9% + 2.5% at 2 years, 88.5% + 3.6% at 5 years, 81.7% + 4.4% at 10 years, 79.7% + 4.8% at 15 years, and 76.2% + 5.7% at 20 years (see Figure 4). Contrary to our first analysis,18 the higher reoperation rate in the bovine pericardium group (33% vs 18% in the remainder) did not reach statistical significance in this updated follow-up (log-rank test, P ¼ .22, see Figure 5). This result was also confirmed when comparing the freedom from reoperation in bovine pericardium compared to all other materials (log-rank test, P ¼ .09). There are limited data available on the results of the aortic valve repair with cusp extension in children with rheumatic aortic insufficiency. Grinda et al reported 89 patients (mean age 16 + 5 years) who underwent cusp extension for rheumatic aortic valve disease.26 Five-year survival and freedom from aortic reoperation were 96% and 92%, respectively. Similarly, Bozbuga et al reported 46 patients with rheumatic valve disease (mean age 35 + 12 years) with survival of 98% at 8.6 years and freedom from reoperation of 76.1% at 7.5 years.27 The longest available results with this technique, with a follow-up of up to 16 years, were reported by Al Halees et al for 92 patients (mean age, 30 years), with mostly rheumatic valve disease.8 The survival rate was 85%. There were no episodes of thromboembolism, and freedom from reoperation was 68% at 10 years and 47% at 16 years.
Discussion Compared to the above-mentioned series, we reported significantly improved results with the three separate fresh autologous pericardial patch aortic cusp extension technique, which takes into account the real dimensions of the retracted native aortic cusps by the rheumatic process. On one hand, the improvement in terms of durability is mainly due to the fact that this technique—contrary to the stereotypic use of excessive patch dimensions—prevents cuspal distortion, redundancy, malalignement inducing turbulences, and on the other hand, it leads to better stress distribution preventing precarious shrinkage of the fresh autologous pericardial patches. Another potential factor that might explain the improved durability could be the avoidance of glutaraldehyde-treated material, which predisposes calcification in children who are subject to
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Figure 4. Kaplan-Meier estimate of freedom from aortic valve reoperation.
a more accelerated calcium metabolism compared to adult population. Causes of early reoperation during the first postoperative six months are technical failures, surgery during the acute phase of pancarditis, the use of autologous pericardium already affected by inflammatory rheumatic pancarditis characterized by the presence of adhesions between pericardium and epicardium, as well as the application of the cusp extension only to one or two more affected cusps and not to all of them. As technical failure, we have noticed in one case a hole within the suturing line between the native cusp and its extension patch. Surgery during the acute phase of pancarditis predisposes to technical problems due to the friable consistency of the inflammatory aortic cusps and the fast conversion of the inflammatory process into fibrous contracture under anti-inflammatory medication. The use of autologous pericardium already affected by pancarditis accelerates the fibrous shrinkage of the pericardial extension patches. For this reason precisely, in our series, we explored the use of alternative patch materials such as PhotoFix and glutaraldehyde-treated bovine pericardium after the manufacturing of the PhotoFix patch was discontinued. In the case of incomplete cusp extension, recurrent aortic insufficiency occurs earlier during the postoperative course
due to the borderline coaptation surface between the extended and the unextended aortic cusps, which are more prone to be affected by progressive fibrous contracture. The causes of reoperation in mid-term and long-term are due to the progressive shrinkage of the fresh autologous pericardium that can also be affected with the same intensity as the native aortic cusps by the repeat postoperative episodes of rheumatic fever due to the noncompliance of the patients to antibiotic prophylaxis in developing countries. In the cases of glutaraldehyde-treated pericardial patches, the progressive calcifying degenerative changes are at the origin of reoperation. The progressive loss of pliability of the extended cusps over the postoperative course usually generates mixed-type aortic valve dysfunction with the regurgitant component being more predominant. The speed with which the fresh pericardium contracts or the glutaraldehyde-treated pericardium calcifies is unpredictable, and certainly depending upon the metabolic factors currently unknown. This review focuses on the specific technique of aortic cusp extension for rheumatic aortic valve disease in children. Although there are numerous patient series on aortic valve repair in children that were recently reviewed,28 most of these series include patients of different ages and with mixed
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Figure 5. Kaplan-Meier estimates of freedom from aortic valve reoperation, stratified by extension patch material.
underlying etiologies of aortic valve disease, predominantly congenital, and few with rheumatic heart disease. Any comparison with these prior publications would thus not focus on the results of the technique but focus on the underlying etiology and mechanism of aortic valve failure and was beyond the scope of this review. Aortic valve replacement using xenograft, homograft, or pulmonary autograft as alternate surgical option to aortic valve repair with cusp extension has not demonstrated any superiority in rheumatic valvular disease.8,29-31 Although it is not recommended by the current guidelines, mechanical prosthesis in the aortic position may carry less risk of thromboembolism, as outcomes in patients only on antiplatelet regimens have been reported to be noninferior to coumadin.32 However, significant drawbacks such as panus formation and acquired patientprosthesis mismatch from somatic growth make mechanical prosthesis less ideal in the pediatric population. In conclusion, although aortic cusp extension is technically more demanding and time consuming, it remains especially more suitable in the context of evolving rheumatic aortic insufficiency in children
with small aortic annulus as a bridge surgical approach to late aortic valve replacement with a larger valvular prosthesis. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Ross DN. Surgical reconstruction of the aortic valve. Lancet. 1963;1(7281): 571-574. 2. Al Fatig MR, Al Kasab SM, Ashmeg A. Aortic valve repair using bovine pericardium for cusp extension. J Thorac Cardiovasc Surg. 1988;96(5): 760-764.
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3. Duran C, Kumar N, Gometza B, Al Halees Z. Indications and limitations of aortic valve reconstruction. Ann Thorac Surg. 1991;52(3): 447-454. 4. Duran C, Gometza B. Aortic valve reconstruction in the young. J Card Surg. 1994;9(suppl 2): 204-208. 5. Duran C, Gometza B, Kumar N, Gallo R, Bjornstad K. From aortic cusp extension to valve replacement with stentless pericardium. Ann Thorac. 1995;60(suppl 2): S428-S432. 6. Duran C, Gallo R, Naresh K. Aortic valve replacement with autologous pericardium: surgical technique. J Card Surg. 1995;10(1): 1-9. 7. Duran C, Gometza B, Kumar N, Gallo R, martin-Duran R. Aortic valve replacement with freehand autologous pericardium. J Thorac Cardiovasc Surg. 1995;110(2): 511-516. 8. Al Halees Z, Al Shadid M, Al Sanei A, Sallehuddin A, Duran C. Up to 16 years follow-up of aortic valve reconstruction with pericardium: a stentless readily available cheap valve? Eur J Cardiothorac Surg. 2005;28(2): 200-205. 9. Tapia M, Brizard C, Fremont D, et al. Chirurgie conservatrice pour insuffisance aortique rhumatismale [in French]. Arch Mal Coeur. 1998;90(12): 1611-1614. 10. Grinda JM, Latremouille C, Berrebi AJ, et al. Aortic cusp extension valvuloplasty for rheumatic aortic valve disease: midterms results. Ann Thorac Surg. 2002;74(4): 438-443. 11.. Senning A. Fascia lata replacement of the aortic valves. J Thorac Cardiovasc Surg. 1988;2: 217-223. 12. Batista RJ, Dobrianskij A, Comazzi M, et al. Clinical experience with stentless pericardial monopatch for aortic valve replacement. J Thorac cardiovasc Surg. 1987;93(1): 19-26. 13. Yacoub M, Khaghani A, Dhalla N, et al. Aortic valve replacement using unstented dura or calf pericardium: early and medium term results. In: Bodnar E, Yacoub M, eds. Biological and Bioprosthetic Valves. New York, NY: Yorke Medical Books; 1986:684-690. 14. Liao K, Frater RW, LaPietra A, Ciuffo G, Ilardi CF, Seifter E. Time-dependent effect of glutaraldehyde on the tendency to calcify of both autografts and xenografts. Ann Thorac Surg. 1995; 60(suppl 2): S343-S347. 15. Carpentier A. Le concept de bioprothe`ses et son application a` la fabrication de mate´riaux biologiques [PhD thesis]. Paris, Orsay: Universite´ d’Orsay; 1975. 16. Kumar SP, Prabhakar G, Kumar M, et al. Comparaison of fresh and glutaraldehyde-treated autologous stented pericardium as pulmonary valve replacement. J Card Surg. 1995;10(5): 545-551. 17. Chauvaud S, Jebara V, Chachques JC, et al. Valve extension with glutaraldehyde-preserved autologous pericardium: results in mitral valve repair. J Thorac Cardiovasc Surg. 1991;102(2): 171-178. 18. Myers PO, Tissot C, Christenson J, Cikirikcioglu M, Aggoun Y, Kalangos A. Aortic valve repair by cusp extension for rheumatic aortic insufficiency in children: Long-term results and impact of
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extension material. J Thorac Cardiovasc Surg. 2010;140(4): 836-844. Badylak SF. The extracellular matrix as a scaffold for tissue reconstruction. Semin Cell Dev Biol. 2002;13(5): 377-383. Quarti A, Nardone S, Colaneri M, Santoro G, Pozzi M. Preliminary experience in the use of an extracellular matrix to repair congenital heart diseases. Interact Cardiovasc Thorac Surg. 2011; 13(6): 569-572. Myers PO, Khalpey Z, Baird CW, Nathan M, del Nido PJ. In vivo valvulogenesis: initial experience with atrioventricular valve leaflet augmentation with cormatrix1 extracellular matrix scaffolds. Circulation. 2012;126: A16130. Nosal M, Poruban R, Valentik P, Sagat M, Nagi AS, Kantorova A. Initial experience with polytetrafluoroethylene leaflet extensions for aortic valve repair. Eur J Cardiothorac Surg. 2012;41(6): 1255-1257. El Khoury G, Vohra HA. Polytetrafluoroethylene leaflet extensions for aortic valve repair. Eur J Cardiothorac Surg. 2012; 41(6): 1258-1259. Farivar RS, Shernan SK, Cohn LH. Late rupture of polytetrafluoroethylene neochordae after mitral valve repair. J Thorac Cardiovasc Surg. 2009;137(2): 504-506. Kalangos A, Beghetti M, Baldovinos A, et al. Aortic valve repair by cusp extension with the use of fresh autologous pericardium in children with rheumatic aortic insufficiency. J Thorac Cardiovasc Surg. 1999;118(2): 225-236. Grinda JM, Latremouille C, Berrebi AJ, et al. Aortic cusp extension valvuloplasty for rheumatic aortic valve disease: midterm results. Ann Thorac Surg. 2002;74(2): 438-443. Bozbuga N, Erentug V, Kirali K, Akinci E, Isik O, Yakut C. Midterm results of aortic valve repair with the pericardial cusp extension technique in rheumatic valve disease. Ann Thorac Surg. 2004;77(4): 1272-1276. Baird CW, Myers PO, del Nido PJ. Aortic valve reconstruction in the young infants and children. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2012;15(1): 9-19. Walker WE, Duncan JM, Frazier OH Jr, et al. Early experience with the Ionescu-Shiley pericardial xenograft valve. Accelerated calcification in children. J Thorac Cardiovasc Surg. 1983;86(4): 570-575. Gerosa G, McKay R, Davies J, Ross DN. Comparison of the aortic homograft and the pulmonary autograft for aortic valve or root replacement in children. J Thorac Cardiovasc Surg. 1991; 102(1): 51-61. Choudhary SK, Mathur A, Sharma R, et al. Pulmonary autograft: should it be used in young patients with rheumatic disease? J Thorac Cardiovasc Surg. 1999;118(3): 483-491. Bradley SM, Sade RM, Crawford FA Jr, Stroud MR. Anticoagulation in children with mechanical valve prostheses. Ann Thorac Surg. 1997;64(1): 30-34.
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Aortic Cusp Extension for Surgical Correction of Rheumatic Aortic Valve Insufficiency in Children Afksendiyos Kalangos and Patrick O. Myers World Journal for Pediatric and Congenital Heart Surgery 2013 4: 385 DOI: 10.1177/2150135113498785 The online version of this article can be found at: http://pch.sagepub.com/content/4/4/385
Published by: http://www.sagepublications.com
On behalf of:
World Society for Pediatric and Congential Heart Surgery
Additional services and information for World Journal for Pediatric and Congenital Heart Surgery can be found at: Email Alerts: http://pch.sagepub.com/cgi/alerts Subscriptions: http://pch.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
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Review Article
Aortic Cusp Extension for Surgical Correction of Rheumatic Aortic Valve Insufficiency in Children
World Journal for Pediatric and Congenital Heart Surgery 4(4) 385-391 ª The Author(s) 2013 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/2150135113498785 pch.sagepub.com
Afksendiyos Kalangos, MD, PhD1, and Patrick O. Myers, MD1
Abstract Surgical management of aortic insufficiency in the young is problematic because of the lack of an ideal valve substitute. Potential advantages of aortic valve repair include low incidences of thromboembolism and endocarditis, avoiding conduit replacements, the maintenance of growth potential, and improved quality of life. Aortic valve repair is still far from fulfilling the three key factors that have allowed the phenomenal development of mitral valve repair (standardization, reproducibility, and stable long-term results); however, techniques of aortic valve repair have been refined, and subsets of patients amenable to repair have been identified. We have focused on the oldest technique of aortic valve repair, cusp extension, focusing on children with rheumatic aortic insufficiency. Among 77 children operated from 2003 to 2007, there was one early death from ventricular failure and one late death from sudden cardiac arrhythmia. During a mean follow-up of 12.8 + 5.9 years, there were 16 (20.5%) reoperations on the aortic valve, at a median of 3.4 years (range, 2 months to 18.3 years) from repair. Freedom from aortic valve reoperation was 96.2% + 2.2% at 1 year, 94.9% + 2.5% at 2 years, 88.5% + 3.6% at 5 years, 81.7% + 4.4% at 10 years, 79.7% + 4.8% at 15 years, and 76.2% + 5.7% at 20 years. Although aortic cusp extension is technically more demanding, it remains particularly more suitable in the context of evolving rheumatic aortic insufficiency in children with a small aortic annulus as a bridge surgical approach to late aortic valve replacement with a larger valvular prosthesis. Keywords aortic valve repair, congenital heart surgery, heart valve, rheumatic Submitted April 26, 2013; Accepted July 01, 2013. Presented at The Sixth World Congress of Paediatric Cardiology and Cardiac Surgery, Cape Town, South Africa; February 17-22, 2013.
Presented at the World Society for Pediatric and Congenital Heart Surgery Symposium on Surgery for Rheumatic Heart Disease at The Sixth World Congress of Paediatric Cardiology and Cardiac Surgery, Cape Town, South Africa; February 17-22 2013.
Introduction Significant limitations of prosthetic valve replacement in the young stimulated the development of valve repair techniques. Standardized, reproducible, and stable long-term results of mitra valve repair are three key factors that encouraged surgeons to apply this conservative approach on the aortic valve. Despite the fact that surgeons are currently far from fulfilling these three key factors in aortic valve repair, they have been able to refine the techniques of aortic valve repair with time and identify a subset of patients amenable to repair.
Rheumatic Aortic Valve Disease: Lesions and Mechanism of Aortic Valve Dysfunction The mitral and aortic valves are the most frequently affected heart valves by rheumatic heart disease, and surgery is usually
required within five to ten years after diagnosis. Progressive transformation of the inflammatory process into fibrosis over time is responsible for impairing valve function. In rheumatic aortic valve involvement, fibrosis increases the cuspal tissue thickness, retracts and sometimes elongates the free edge of one or more cusps, deforms them gradually, and subsequently predisposes them to calcification. In children, the mobility of the thickened and retracted cusps is somewhat preserved, the cusp involvement by fibrosis being attenuated, with a macroscopically thinned and normal appearance in some patients. Cusp prolapse caused by the elongation of the free edge of one or more aortic leaflets can be seen in 40% to 55% of the patients. The aortic annulus usually remains normal or minimally dilated in children. 1 Division of Cardiovascular Surgery, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland
Corresponding Author: Afksendiyos Kalangos, Division of Cardiovascular Surgery, Geneva University Hospitals and Faculty of Medicine, 4, Rue Gabrielle-Perret-Gentil, 1211 Geneva, Switzerland. Email: [email protected]
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In the majority of patients, the resulting dysfunction is central aortic insufficiency. However, in some patients, the central leak is associated with a varying degree of mild to moderate stenosis due to the inconsistent intensity of commissural fusion.
Aortic Cusp Extension as the Oldest of the Aortic Valve Repair Techniques The aim of aortic cusp extension is to correct the lack of coaptation between the aortic cusps resulting in aortic valve regurgitation, by establishing a new surface of coaptation by extending the cusps using different patch materials, up to the level of the sinotubular junction. With respect to the shape of the extension patch, the tendency has evolved over the past 30 years from a single-patch to a three-patch configuration.1-10 In none of these published series, the real dimensions of native aortic cusps had been taken into account in the tailoring process of the extension patches, probably due to the fact that in some of them, the cusps were either totally or partially excised by eliminating the thickened part of the cusps, leaving an equal height of the remaining tissue in each cusp before reconstruction. In the majority of patients with rheumatic aortic insufficiency, cusps have a varying degree of retraction and deformity, rendering them nonidentical to each other in terms of cusp height, length of free edge, and thickness. For precisely this reason, we have conceived a more geometric concept of cusp extension by reestablishing only the dimensions required to reconstruct three identical cusps in terms of height and cuspal free edge, by moving the new coaptation level up to the sinotubular junction. The choice of extension material is the second important point, which could potentially influence the durability of aortic valve repair over time. After the first attempts by Yacoub and Senning who utilized the dura mater and the fascia lata as patch material, respectively, promising mid-term clinical results have been reported by authors who used glutaraldehyde-treated bovine pericardium after partially excising aortic cusps.11-13 Interest was then focused on using autologous pericardium, probably triggered also by the rapid structural deterioration and primary tissue failure observed with heterograft bioprostheses and homograft valves in children. The literature concerning the use of fresh or glutaraldehydetreated autologous pericardium seems to be divided. Fresh autologous pericardium shows progressive retraction with gradual loss of pliability due to fibrous degenerative changes over time (Figure 1). Autologous pericardium treated in 0.62% glutaraldehyde-buffered solution for 30 minutes behaves like glutaraldehyde-treated heterologous pericardium in terms of calcification tendency.14 Shorter treatment (15 minutes) was proposed for slowing down the excessive fibrous tissue formation observed in the case of fresh autologous pericardium and the calcification observed in the case of glutaraldehyde treatment of longer duration.15 Although the promising experimental and clinical studies showed that the short glutaraldehyde-treated autologous pericardium does not calcify and shrink after implantation,14,16,17 Liao et al found that even short treatment may be enough to change the biologic identity of the autologous
Figure 1. Microscopic section of leaflet after cusp extension with fresh autologous pericardium (hematoxylin & eosin stain). The arrowhead denotes the junction between the native leaflet tissue (below), which is relatively thin and mobile, and the extension material (above), which has retracted and calcified.
pericardium, resulting in a ‘‘foreign body’’ reaction by the host, characterized by pericardial inflammation.14 In our series, the PhotoFix bovine pericardium (Cardiofix; Sorin Carbomedics, Milano, Italy), which uses dye-mediated photooxidation rather than chemical cross-linking of the collagen fibers, showed better durability than glutaraldehyde-treated bovine pericardium,18 although calcification in long term is not excluded (Figure 2). As the manufacturing of this material is currently discontinued, the search for the ideal patch material is still ongoing, and many groups have focused their attention on extracellular matrix (ECM) bioscaffolds in aortic valve repair. The ECM scaffolds that remain essentially unchanged from native ECM elicit a host response that promotes cell infiltration and rapid scaffold degradation, deposition of host-derived neomatrix, and constructive tissue remodeling with minimal scar tissue; this represents a fundamentally different scaffold material than ECM that has been chemically or otherwise modified.19 CorMatrix (CorMatrix, Roswell, Georgia) is a bioscaffold made from intestinal submucosa which has been approved by the US Food and Drug Administration for intracardiac repair.20 Based on the in vitro and in vivo animal studies, this bioscaffold was shown to be progressively replaced with autologous tissue from autologous tissue on the edge of the patch. The patch needs to be entirely encircled by autologous tissue (ie, implanted at the base of the leaflet rather than on the free edge) or colonization of the patch before biodegradation would not be
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387 theoretical advantage of being relatively stable and noncalcifing. Although used at other sites in the heart, the reported clinical experience in aortic valve repair with this material is limited to just 13 adult patients with a mean follow-up of 14.8 months,22 and there are no reports on cusp extension with this patch material in children. From a theoretical standpoint, PTFE is a durable monofilament plastic polymer that has unique characteristics, including flexibility, remarkable breaking strength, negative charge (like the native endothelium), and biostability.23 Larger mid- and long-term follow-up data and reports of its use in aortic valve repair in children are still pending, and this material may be at risk of calcification23 or late fracture.24
Aortic Cusp Extension Technique
Figure 2. PhotoFix pericardium cusp extension. A, PhotoFix pericardium cusp extension five years later. Surgical view of the repaired aortic valve (AV) in a patient requiring reoperation for mitral valve (MV) repair five years after PhotoFix (Sorin CarboMedics) cusp extension. The extensions were pliable, and presented no calcifications or retraction. Reproduced with permission from Myers et al.18 B, Leaflets 12 years after PhotoFix cusp extension, showing thickening and calcification.
complete. Its application in heart valve repair is relatively new, and there is a paucity of data available. Currently, there are no reported data available on the results of aortic valve with CorMatrix. In a retrospective study of 25 children with congenital mitral or tricuspid lesions who underwent leaflet patch augmentation with CorMatrix, the reoperation rate was similar to matched controls who had leaflet patch augmentation with glutaraldehyde-treated pericardium at 12-month follow-up, although the mechanism of failure tended to differ, with more patch retractions in the pericardium group.21 Expanded polytetrafluoroethylene (PTFE) has been proposed as a leaflet repair patch material. The PTFE has the
A large rectangular piece of anterior autologous pericardium is harvested and applied on a wet woven Dacron patch or a surgical wrap fabric with its mesothelial surface upward if the surgeon decides to use it as a fresh material. In this case, the Dacron patch or the piece of surgical wrap fabric serves as a template for sizing, trimming, and handling these template materials are not being necessary if the autologous pericardium is treated with glutaraldehyde. The loose fatty areolar tissue is removed by blunt dissection. After obtaining cardiac arrest by selective cardioplegia into both coronary ostia through a transverse aortotomy, the aortic valve is exposed with three stay sutures placed at the lower and upper flaps of the aortotomy. All aortic cusps are first inspected with particular regard to the valve morphology, commissural fusion, cusp prolapse, degree of retraction, cusp calcification, and appearance of the sinuses of Valsalva. The length of each cuspal free edge and height as well as the sinotubular junction and aortic annulus diameter are then measured. Subsequently, based on the measurements of each cusp, the shape of each pericardial patch is traced onto the template fabric or glutaraldehyde-treated pericardium (Figure 3A). In Figure 3B, the dimension B to D equals to the diameter of the sinotubular junction plus 15% of this diameter to account for eventual loss resulting from the progressive shrinkage of the fresh pericardium over time. In the case of glutaraldehyde-fixed autologous or heterologous pericardium, this 15% oversizing of the dimensions B to D is not necessary. The G to I equals to the length of the cuspal free edge. The height of both the commissural extensions (A-F and E-J) is equal to 3 mm. The C-H is designed according to the distance between the middle of each cusp’s axis and the level of sinotubular junction and oversized by approximately 2 mm to allow for suturing the patch on the cuspal free edge of each corresponding aortic cusp. The G to H equals to the length of the free edge of each corresponding aortic cusp. Suturing of the patches on the free edge of each corresponding aortic cusp starts at the midpoint of the cusp and goes up to both the opposite commissures using the two arms of the 5-0 monofilament suture material. These running sutures are finally brought out through the aortic wall between the native commissure and its above placed pericardial extension fixed on the aortic wall by two 5-0 monofilament mattress stitches tied outside the aorta. The running sutures of neighboring aortic
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Figure 3. Surgical technique of cusp extension. Reproduced with permission from Kalangos et al.22
cusps brought out through the commissural part of the aorta, as described previously, are tied together outside the aorta. The cusps are thinned, and a concomitant commissurotomy is performed if their mobility is restricted. The eventual occlusion of the coronary ostia by direct apposition of the patches to the wall of sinuses of Valsalva can be avoided by not exceeding the height of the extended cusps above the level of sinotubular junction as well as by not exceeding the length of each cusp free edge more than the diameter of the sinotubular junction in the case of glutaraldehyde-treated pericardium and plus 15% of this diameter in case of fresh autologous pericardium. Figure 3H shows that the shape of each of the three pericardial extensions is different, due to the variable intensity of retraction and deformity of each of the native aortic cusps.
Mid- and Long-term Results of Aortic Cusp Extension for the Surgical Management of Rheumatic Aortic Insufficiency We previously reviewed our mid-25 and long-term18 results of aortic cusp extension in children with rheumatic aortic insufficiency. From 2003 to 2007, 78 consecutive children underwent
aortic cusp extension for this indication. The material used for cusp extension was fresh autologous pericardium in 53 (68%) patients. In 25 (32%) patients, the pericardium was not deemed usable and an alternative, off-the-shelf pericardium was used, PhotoFix bovine pericardium (Cardiofix, Sorin CarboMedics) in 16 (21%) patients and glutaraldehyde-fixed bovine pericardium (St Jude Medical Inc, St Paul, Minnesota) in 9 (12%) patients when Cardiofix was discontinued. There was one early death from ventricular failure and one late death from sudden cardiac arrhythmia. During a mean follow-up of 12.8 + 5.9 years, there were 16 (20.5%) reoperations on the aortic valve, at a median of 3.4 years (range, 2 months to 18.3 years) from repair. There were ten reoperations in the fresh autologous pericardium group (18.9%), three in the bovine pericardium group (33.3%) and three in the PhotoFix group (18.8%, Fisher exact test, P ¼ .62). Freedom from aortic valve reoperation was 96.2% + 2.2% at 1 year, 94.9% + 2.5% at 2 years, 88.5% + 3.6% at 5 years, 81.7% + 4.4% at 10 years, 79.7% + 4.8% at 15 years, and 76.2% + 5.7% at 20 years (see Figure 4). Contrary to our first analysis,18 the higher reoperation rate in the bovine pericardium group (33% vs 18% in the remainder) did not reach statistical significance in this updated follow-up (log-rank test, P ¼ .22, see Figure 5). This result was also confirmed when comparing the freedom from reoperation in bovine pericardium compared to all other materials (log-rank test, P ¼ .09). There are limited data available on the results of the aortic valve repair with cusp extension in children with rheumatic aortic insufficiency. Grinda et al reported 89 patients (mean age 16 + 5 years) who underwent cusp extension for rheumatic aortic valve disease.26 Five-year survival and freedom from aortic reoperation were 96% and 92%, respectively. Similarly, Bozbuga et al reported 46 patients with rheumatic valve disease (mean age 35 + 12 years) with survival of 98% at 8.6 years and freedom from reoperation of 76.1% at 7.5 years.27 The longest available results with this technique, with a follow-up of up to 16 years, were reported by Al Halees et al for 92 patients (mean age, 30 years), with mostly rheumatic valve disease.8 The survival rate was 85%. There were no episodes of thromboembolism, and freedom from reoperation was 68% at 10 years and 47% at 16 years.
Discussion Compared to the above-mentioned series, we reported significantly improved results with the three separate fresh autologous pericardial patch aortic cusp extension technique, which takes into account the real dimensions of the retracted native aortic cusps by the rheumatic process. On one hand, the improvement in terms of durability is mainly due to the fact that this technique—contrary to the stereotypic use of excessive patch dimensions—prevents cuspal distortion, redundancy, malalignement inducing turbulences, and on the other hand, it leads to better stress distribution preventing precarious shrinkage of the fresh autologous pericardial patches. Another potential factor that might explain the improved durability could be the avoidance of glutaraldehyde-treated material, which predisposes calcification in children who are subject to
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Figure 4. Kaplan-Meier estimate of freedom from aortic valve reoperation.
a more accelerated calcium metabolism compared to adult population. Causes of early reoperation during the first postoperative six months are technical failures, surgery during the acute phase of pancarditis, the use of autologous pericardium already affected by inflammatory rheumatic pancarditis characterized by the presence of adhesions between pericardium and epicardium, as well as the application of the cusp extension only to one or two more affected cusps and not to all of them. As technical failure, we have noticed in one case a hole within the suturing line between the native cusp and its extension patch. Surgery during the acute phase of pancarditis predisposes to technical problems due to the friable consistency of the inflammatory aortic cusps and the fast conversion of the inflammatory process into fibrous contracture under anti-inflammatory medication. The use of autologous pericardium already affected by pancarditis accelerates the fibrous shrinkage of the pericardial extension patches. For this reason precisely, in our series, we explored the use of alternative patch materials such as PhotoFix and glutaraldehyde-treated bovine pericardium after the manufacturing of the PhotoFix patch was discontinued. In the case of incomplete cusp extension, recurrent aortic insufficiency occurs earlier during the postoperative course
due to the borderline coaptation surface between the extended and the unextended aortic cusps, which are more prone to be affected by progressive fibrous contracture. The causes of reoperation in mid-term and long-term are due to the progressive shrinkage of the fresh autologous pericardium that can also be affected with the same intensity as the native aortic cusps by the repeat postoperative episodes of rheumatic fever due to the noncompliance of the patients to antibiotic prophylaxis in developing countries. In the cases of glutaraldehyde-treated pericardial patches, the progressive calcifying degenerative changes are at the origin of reoperation. The progressive loss of pliability of the extended cusps over the postoperative course usually generates mixed-type aortic valve dysfunction with the regurgitant component being more predominant. The speed with which the fresh pericardium contracts or the glutaraldehyde-treated pericardium calcifies is unpredictable, and certainly depending upon the metabolic factors currently unknown. This review focuses on the specific technique of aortic cusp extension for rheumatic aortic valve disease in children. Although there are numerous patient series on aortic valve repair in children that were recently reviewed,28 most of these series include patients of different ages and with mixed
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Figure 5. Kaplan-Meier estimates of freedom from aortic valve reoperation, stratified by extension patch material.
underlying etiologies of aortic valve disease, predominantly congenital, and few with rheumatic heart disease. Any comparison with these prior publications would thus not focus on the results of the technique but focus on the underlying etiology and mechanism of aortic valve failure and was beyond the scope of this review. Aortic valve replacement using xenograft, homograft, or pulmonary autograft as alternate surgical option to aortic valve repair with cusp extension has not demonstrated any superiority in rheumatic valvular disease.8,29-31 Although it is not recommended by the current guidelines, mechanical prosthesis in the aortic position may carry less risk of thromboembolism, as outcomes in patients only on antiplatelet regimens have been reported to be noninferior to coumadin.32 However, significant drawbacks such as panus formation and acquired patientprosthesis mismatch from somatic growth make mechanical prosthesis less ideal in the pediatric population. In conclusion, although aortic cusp extension is technically more demanding and time consuming, it remains especially more suitable in the context of evolving rheumatic aortic insufficiency in children
with small aortic annulus as a bridge surgical approach to late aortic valve replacement with a larger valvular prosthesis. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
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