World Journal for Pediatric and Congenital Heart Surgery http://pch.sagepub.com/
Systematic Approach to Aortic Valvuloplasty in Children and Young Adults Chawki ElZein, Sujata Subramanian, Anastasios C. Polimenakos, David Roberson and Michel N. Ilbawi World Journal for Pediatric and Congenital Heart Surgery 2013 4: 412 DOI: 10.1177/2150135113504598 The online version of this article can be found at: http://pch.sagepub.com/content/4/4/412
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On behalf of:
World Society for Pediatric and Congential Heart Surgery
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Review Article
Systematic Approach to Aortic Valvuloplasty in Children and Young Adults
World Journal for Pediatric and Congenital Heart Surgery 4(4) 412-417 ª The Author(s) 2013 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/2150135113504598 pch.sagepub.com
Chawki ElZein, MD1,2, Sujata Subramanian, MD1,2, Anastasios C. Polimenakos, MD1,2, David Roberson, MD1,2 and Michel N. Ilbawi, MD1,2
Abstract Valve repair in children and young adults is an attractive alternative to replacement or Ross procedure. In the past, the various valvuloplasty techniques have addressed isolated valve pathology. Recently, however, a holistic approach involving repair of all aortic root structures has evolved and promised to be an excellent alternative to valve replacement. It provides good long-term results and avoids all the drawback of prosthetic valve insertion in this age group. Development of ideal patch material needed for valve repair and better understanding of the anatomy and function of the aortic root may further improve the short- and long-term outcomes of aortic valvuloplasty. Keywords annuloplasty (indicate location), aortic operation, aortic valve, repair, aortic root Submitted July 31, 2013; Accepted August 15, 2013. Presented at the Congenital Heart Surgery Symposium of the 49th annual meeting of the Society of Thoracic Surgeons, Los Angeles, USA, January 2013.
The lack of ideal valve substitute in children with aortic valve disease has prompted the search for a better alternative to valve replacement. The uncertainty of the long-term results of the Ross procedure, especially in patients with regurgitation and dilated aortoventricular junction, makes valvuloplasty an attractive option in this age group.1 Several aortic valvuloplasty techniques have been described. Most have focused on tackling one aspect of valve pathology. Little emphasis has been placed on comprehensive repair based on a thorough evaluation of the pathology and the pathophysiology of the diseased valve. This has led to suboptimal longterm results. Recently, the cumulative experience with aortic valve repair both in children and in adults has identified a very important principle that is essential for optimal outcome, namely, that aortic valve disease is a root disease. As a result, pre- and intraoperative evaluations are currently directed at the aortic root as a whole, and the techniques being used target all the defective root structures thus optimizing outcome.2
The Pathology of the Aortic Root in Aortic Valve Disease Normal valve function depends on several root structures and their interaction throughout the cardiac cycle. These structures are listed subsequently.
Zone I: The Aortoventricular Junction (So-Called Annulus) The dynamic nature of this zone is very important for appropriate opening and closure of the valve leaflets. The subcommissural or interleaflet triangles follow the ventricular contraction and allow optimal leaflet retraction during systole. In patients with aortic valvar stenosis, this junction is usually hypoplastic, with or without fibrous attachments to the leaflets. The subcommissural triangle is attenuated, limiting normal leaflet excursion. On the other hand, in patients with regurgitation, the aortoventricular junction is dilated, resulting in flattening and stretching of the leaflets.
Zone II: The Leaflets and Sinuses The parabolic shape of the leaflets (suspension bridge) allows free movement during systole and coaptation during diastole. In stenosis, the valve is frequently bicuspid, the leaflets are 1 Division of Pediatric Cardiology and Cardiac Surgery, Hope Children’s Hospital, Oak Lawn, IL, USA 2 Division of Cardiothoracic Surgery, University of Illinois, IL, USA
Corresponding Author: Chawki ElZein, Advocate Christ Medical Center, The Heart Institute for Children, 4440 West 95th Street, Oak Lawn, IL, USA. Email: [email protected]
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attenuated both in length and in depth, and the fusion of two leaflets results in eccentric valve opening. In regurgitation, the leaflet edges are usually thickened, rolled, and often stretched and flat. The root sinuses are often dilated.
Zone III: The Sinotubular Bar The sinotubular bar marks the junction with the ascending aorta. It acts as a suspension post that supports the peripheral attachment of the leaflets. In stenotic valves, the bar is restrictive, while in regurgitation it is dilated, and the intercommissural distance is increased.
Techniques of Aortic Valvuloplasty Surgical intervention should be guided by a comprehensive preand intraoperative two- and three-dimensional echocardiographic evaluation to identify the different pathologies in the three aortic root zones and tailor the technical steps accordingly.
Operative Steps: Zone I In patients with stenotic ventricular aortic junction, thorough mobilization of the subcommissural triangle is achieved by deep perpendicular incision extending proximally into the ventricular muscle and distally into the fused commissures. The incision also mobilizes the crowded and narrow area of attachment of the leaflets in both the directions along the aortic wall. Dissection of any subvalvar fibrous tissue, whether in the triangle or at the leaflet attachments, is performed (Figure 1). Reduction in the dilated junction is achieved by either internal or external annuloplasty. In the internal approach, a double row of nonabsorbable sutures is passed in and out along the perimeter of the junction. The suture is tightened over a dilator or valve sizer to achieve a diameter of þ1 to þ2 Z value (11 + 1 mm/m2). External annuloplasty on the other hand requires mobilization of the coronary arteries and the structures surrounding the root. A band of polyterafluoroethylene or other material (3-5 mm in width) is passed around the root and tightened on a sizer to achieve the desired Z value (Figure 2).
Operative Steps: Zone II Leaflet perforation is easily repaired using a patch sutured to the perimeters of the hole. Direct closure of these defects should be avoided (Figure 3). Several techniques have been used to address leaflet prolapse. A half purse-string suture, passed along the edge of the leaflet and tightened after securing its ends to the aortic wall, achieves the desired effect (Figure 4). Plication of the redundant leaflet and resuspension of the plicated segment to the aortic wall can also be used as an alternative, provided that the leaflet does not become distorted (Figure 4). Another option is resection of a triangle wedge of the prolapsed cusp. Implantation of chordae on the prolapsing leaflet has been described.3 Commissural fusion has to be completely relieved. The incision is extended into the aortic wall on both sides of the
Figure 1. Extended commissurotomy with complete relief of leaflet fusion and mobilization of the subcommissural triangle.
commissure to mobilize the leaflet and the subcommissural triangle.4 The thickened and rolled leaflet edges are thinned out and nodules shaved. Bicuspid valves with eccentric openings are tricupidized to achieve a central opening (Figure 5).5-8 Attenuated leaflets or leaflets without adequate commissural support resulting from the extended commissuratory or tricuspidization are augmented with patch material to achieve the normal leaflet configuration (Figure 6). The patch is tailored to fit the depth and length of the leaflets (Figure 7).8 The extent of augmentation should not be excessive to avoid crowding of the root and is based on direct relationship between the intercommissural distance and the leaflet dimensions (Figures 8 and 9).9 Management of dilated aortic root sinuses is evolving. Wrapping the root externally with a semirigid cylinder (15 + 1, 5 mm/m2 at the sinuses) may halt the dilatation but would affect growth potential (Figure 10). Replacement of the dilated sinus with rigid patches may be helpful.10
Operative Steps: Zone III A stenotic or hypoplastic sinotubular bar is managed by cutting through it and enlarging the area with a patch to normalize its diameter (Z value 0-1).10 On the other hand, the dilated bar should be reduced by cutting a triangular wedge of the aortic root wall to normalize its diameter. Intussusception of the dilated sinotubular bar into a normal diameter ascending aorta has also been used.11
Results Reported short- and long-term results of aortic valvuloplasty have varied considerably. Factors that contributed to durability of the repair included anatomic features of the valve, the etiology of the valve pathology, the age at repair, and the techniques used. In a review of 316 adult patients operated on between 1995 and 2008, hospital mortality was 0.63%, and the tenyear survival was 92%. Freedom from reoperation was 81%
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Figure 2. Internal and external annuloplasty.
Figure 3. Management of leaflet perforation.
Figure 4. Techniques for repair of leaflet prolapse.
Figure 5. Tricuspidization of bicuspid aortic valve with eccentric opening. The rudimentary commissure is opened.
at ten years. Dilated aortoventricular diameter, effective cusp height, and subcommissural plication were found to contribute to repair failure.12 Luciani et al reported on singular group of 147 patients operated on between 2002 and 2011. There was no hospital mortality and three late deaths. Freedom from reoperation was 95% + 3% at eight-year follow-up.13 The longest experience in pediatric patients was reported by Polimenakos et al. Median follow-up was 14.4 years. There was no early or late death in the group. Freedom from reoperation (repair or replacement) was 60% + 7.2% at 18 years. Tricuspidization to achieve central valve orifice and absence of small ventricular aortic junction were among the factors that contributed to longer longevity of the repair.5 In a report of another large series, d’Udekem et al cautioned against tricuspidization and cusp extension because of potential occlusion of the coronary ostia by the extended cusps, a finding not reported by others.14 In the same series,
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Figure 9. Completed augmentation and resuspension of the constructed leaflets.
Figure 6. Patch augmentation of defective leaflet. The reconstructed leaflet is suspended to aortic wall.
Figure 10. External support to minimize sinus dilatation.
Figure 7. The depth and length of leaflet augmentation is based on the relationship between the intercommissural triangle and the leaflet depth.
seven-year freedom from reoperation was 80%. Infants did not fare well. Other experiences with valvuloplasty had similar long-term results.15,16 When patient matching is applied to repair versus replacement populations, repair was found to have results comparable or better than patients with bioprosthesis.17
Comments
Figure 8. Resuspension of the constructed leaflets.
The improved short- and long-term results of aortic valvuloplasty in congenital and acquired aortic valve disease are due to the improved understanding of the pathology and pathophysiology of the diseased aortic valve as well as better valve imaging techniques. Data reported from different centers have shown acceptable long-term outcomes following valvuloplasty with very low rates of morbidity or mortality. When compared with the Ross procedure, valvuloplasty provides a good alternative, especially in patients with bicuspid aortic valve or dilated ventricular aortic junction, in whom the pulmonary autograft has demonstrated early postoperative dilatation and dysfunction. Valvuloplasty improves aortic valvar function without compromising the pulmonary valve, thus leaving all other surgical options open for future use. It has a distinct advantage over tissue valve implantation, as it can be used in smaller children whose ventriculoaortic junction (annulus) is smaller than commercially available tissue or even mechanical valves.
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It also does not restrict the growth of the junction as the rigid ring of the prosthetic valve does. In addition, the strut of the tissue valve can interrupt the coordinated movement of the left ventricle, aortic valve, aortic sinuses, and ascending aorta.18 These factors, combined with no need for anticoagulation, make valve repair the most optimal option in smaller children with serious valve dysfunction. Although there has been no controlled prospective study, the long-term performance of aortic valvuloplasty has been acceptable and is definitely better than that reported for tissue valves in the young population. The continued modifications and improvements in the repair techniques make comparison with the standard tissue valve insertion difficult to validate. Moreover, old valve repair techniques have tackled only one of the many pathological features of the dysfunctional aortic valve. The improved understanding of the different lesions affecting the congenital aortic valve and the holistic approach to the aortic root should certainly improve the results, especially as different centers gain experience with a large number of patients on whom a comprehensive approach to repair has been used. One of the factors that have compromised the long-term outcome of valve repair is the absence of tissue material that is optimal for valve reconstruction. In the authors’ experience, the use of autologous pericardium, whether fresh or fixed with variable concentrations of glutaraldehyde, has resulted in early disruption or hardening and calcification of the constructed leaflet. Bovine pericardium fixed with infrared waves resulted in early disruption of the repaired leaflets. Currently, the use of porcine decellularized small intestinal submucosa is favored, but short- and long-term results are lacking. Obviously, once an ideal patch is available, the valvuloplasty technique would become the procedure of choice. Another limitation to surgical valvuloplasty is the stenotic or subnormal valve ventriculoaortic junction (the annulus). In these cases, the repair might result in crowding of the root and early restenosis. The selective operative approach in which this subgroup of patients are treated with Ross or Ross/Konno procedures has decreased the failure rate of the valvuloplasty. Better understanding of the role played by the different components of the aortic root should further improve the valvuloplasty results. Data from the ongoing study of the relationship between the different dimensions of the leaflets and their commissural attachments in the normal and abnormal valve are likely to result in a more anatomic and functional valve repair. One aspect that needs further evaluation is the role of the sinus of Valsalva in valve function. Although it is well known that vortex patterns forming in the sinuses soon after systole modulate leaflet movements and ensure synchronous, homogeneous, and stress-free closure, little is known about the role of the sinuses in valve opening.19 Moreover, the degree of pathology of the sinuses in aortic valve disease is variable and relatively not well known. Therefore, a comprehensive knowledge of the pathology and function of the sinuses is needed in order to plan a sound surgical approach and achieve successful valve repair.20-22
Conclusion Surgical aortic valvuloplasty provides an excellent alternative for management of valve disease in small children. Selective approach, whereby the repair is used primarily in instances of dilated valve annulus and bicuspid valves, provides very satisfactory short- and long-term results. Further studies on the patch material used in the repair and better understanding of the pathophysiology of the aortic root may yield improved results in the future. 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. Charitos EI, Takkenberg JJ, Hanke T, et al. Reoperations on the pulmonary autograft and pulmonary homograft after the Ross procedure: an update on the German Dutch Ross registry. J Thorac Cardiovasc Surg. 2012;144(4): 813-823. 2. Pettersson GB, Crucean AC, Savage R, et al. Toward predictable repair of regurgitant aortic valves. J Am Coll Cardiol. 2008;52(1): 40-49. 3. Fattouch K, Sampognaro R, Bianco G, et al. Implantation of Gore-Tex chordae on aortic valve leaflet to treat prolapse using ‘‘the chordae technique’’: surgical aspects and clinical results. Ann Thorac Surg. 2008;85(6): 2019-2025. 4. Schafers HJ, Aicher D, Riodionycheva S, et al. Bicuspidization of the unicuspid aortic valve: a new reconstructive approach. Ann Thorac Surg. 2008;85(6): 2012-2018. 5. Polimenakos AC, Sathananda S, ElZein C, Barth MJ, Higgens SD, Ilbawi MN. Aortic cusp extension valvuloplasty with or without tricuspidization in children and adolescents: long-term results and freedom from aortic valve replacement. J Thorac Cardiovasc Surg. 2010;139(4): 933-941. 6. Doss M, Moid R, Wood JP, Miskovic A, Martens S, Moritz A. Pericardial patch augmentation for reconstruction of incompetent bicuspid aortic valves. Ann Thorac Surg. 2005;80(1): 304-308. 7. McMullan DM, Oppido G, Davies B, et al. Surgical strategy for the bicuspid aortic valve: tricuspidization with cusp extension versus pulmonary autograft. J Thorac Cardiovasc Surg. 2007; 134(1): 90-98. 8. Pretre R, Kadner A, Dave H, Bettex D, Genoni M. Tricuspidisation of the aortic valve with creation of a crown-line annulus is able to restore a normal valve function in bicuspid aortic valves. Eur J Cardiothorac Surg. 2006;29(6): 1001-1006. 9. Bierbach BO, Aicher D, Abu Issa O, et al. Aortic root and cusp configuration determine aortic valve function. Eur J Cardiothorac Surg. 2010;38(4): 400-406. 10. Kirklin JK, Johnson WH, Cook BB, et al. Novel technique of valve-sparing aortic root replacement in two children younger than 3 years of age. Ann Thorac Surg. 2012;94(1): 299-301.
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11. Kaczorowski DJ, Woo YJ. Aortic valve repair by sinotubular junctional remodeling to eliminate aortic regurgitation in donor cardiac allograft. J Thorac Cardiovas Surg. 2012;144(3): 722-724. 12. Aicher D, Kunihara T, Abu Issa O, Brittner B, Graber S, Schafers HJ. Valve configuration determines long-term results after repair of the bicuspid aortic valve. Circulation. 2011;123(2): 178-185. 13. Luciani GB, DeRita F, Lucchese G, et al. Repair of congenitally dysplastic aortic valve by bicuspidization: midterm results. Ann Thorac Surg. 2012;94(4): 1173-1179. 14. d’Udekem Y, Siddiqui J, Seaman CS, et al. Long-term results of a strategy of aortic valve repair in the pediatric population. J Thorac Cardiovasc Surg. 2013;145(2): 461-469. 15. Bacha EA, McElhinnery DB, Guleserian KJ, et al. Surgical aortic valvuloplasty in children and adolescents with aortic regurgitation: acute and intermediate effects on aortic valve function and left ventricular dimensions. J Thorac Cardiovasc Surg. 2008; 135(3): 552-529. 16. Hawkins JA, Kouretas PC, Holubkov R, et al. Intermediateterm results of repair for aortic, neoaortic, and truncal valve
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insufficiency in children. J Thorac Cardiovasc Surg. 2007; 133(5): 1311-1317. Ashikhmina E, Sundt TM III, Dearani JA, Connolly HM, Li A, Schaff HV. Repair of the bicuspid aortic valve: a viable alternative to replacement with a bioprosthesis. J Thorac Cardiovasc Surg. 2010;139(6): 1395-1401. Kawase I, Ozaki S, Yamashita H, et al. Aortic valve reconstruction of unicuspid aortic valve by tricuspidization using autologous pericardium. Ann Thorac Surg. 2012;94(4): 1180-1184. Pisani G, Scaffa R, Ieropoli O, et al. Role of the sinuses of Valsalva on the opening of the aortic valve. J Thorac Cardiovasc Surg. 2013;145(4): 999-1003. Chen LW, Dai XF, Wu XJ, Zhang GC. Valve-sparing root replacement with root reduction plasty and patch neointima placement. Ann Thorac Surg. 2013;95(4): 1459-1461. Lansac E, Lim HS, Shomura Y, et al. A four dimensional study of the aortic root dynamics. Eur J Cardiothorac Surg. 2002;22(4): 497-403. Price J, De Kerchove L, Glineur D, Vanoverschelde JL, Noirhomme P, El Khoury G. Risk of valve-related events after aortic valve repair. Ann Thorac Surg. 2013;95(2): 606-613.
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Systematic Approach to Aortic Valvuloplasty in Children and Young Adults Chawki ElZein, Sujata Subramanian, Anastasios C. Polimenakos, David Roberson and Michel N. Ilbawi World Journal for Pediatric and Congenital Heart Surgery 2013 4: 412 DOI: 10.1177/2150135113504598 The online version of this article can be found at: http://pch.sagepub.com/content/4/4/412
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
>> Version of Record - Oct 10, 2013 What is This?
Downloaded from pch.sagepub.com at UCSF LIBRARY & CKM on December 8, 2014
Review Article
Systematic Approach to Aortic Valvuloplasty in Children and Young Adults
World Journal for Pediatric and Congenital Heart Surgery 4(4) 412-417 ª The Author(s) 2013 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/2150135113504598 pch.sagepub.com
Chawki ElZein, MD1,2, Sujata Subramanian, MD1,2, Anastasios C. Polimenakos, MD1,2, David Roberson, MD1,2 and Michel N. Ilbawi, MD1,2
Abstract Valve repair in children and young adults is an attractive alternative to replacement or Ross procedure. In the past, the various valvuloplasty techniques have addressed isolated valve pathology. Recently, however, a holistic approach involving repair of all aortic root structures has evolved and promised to be an excellent alternative to valve replacement. It provides good long-term results and avoids all the drawback of prosthetic valve insertion in this age group. Development of ideal patch material needed for valve repair and better understanding of the anatomy and function of the aortic root may further improve the short- and long-term outcomes of aortic valvuloplasty. Keywords annuloplasty (indicate location), aortic operation, aortic valve, repair, aortic root Submitted July 31, 2013; Accepted August 15, 2013. Presented at the Congenital Heart Surgery Symposium of the 49th annual meeting of the Society of Thoracic Surgeons, Los Angeles, USA, January 2013.
The lack of ideal valve substitute in children with aortic valve disease has prompted the search for a better alternative to valve replacement. The uncertainty of the long-term results of the Ross procedure, especially in patients with regurgitation and dilated aortoventricular junction, makes valvuloplasty an attractive option in this age group.1 Several aortic valvuloplasty techniques have been described. Most have focused on tackling one aspect of valve pathology. Little emphasis has been placed on comprehensive repair based on a thorough evaluation of the pathology and the pathophysiology of the diseased valve. This has led to suboptimal longterm results. Recently, the cumulative experience with aortic valve repair both in children and in adults has identified a very important principle that is essential for optimal outcome, namely, that aortic valve disease is a root disease. As a result, pre- and intraoperative evaluations are currently directed at the aortic root as a whole, and the techniques being used target all the defective root structures thus optimizing outcome.2
The Pathology of the Aortic Root in Aortic Valve Disease Normal valve function depends on several root structures and their interaction throughout the cardiac cycle. These structures are listed subsequently.
Zone I: The Aortoventricular Junction (So-Called Annulus) The dynamic nature of this zone is very important for appropriate opening and closure of the valve leaflets. The subcommissural or interleaflet triangles follow the ventricular contraction and allow optimal leaflet retraction during systole. In patients with aortic valvar stenosis, this junction is usually hypoplastic, with or without fibrous attachments to the leaflets. The subcommissural triangle is attenuated, limiting normal leaflet excursion. On the other hand, in patients with regurgitation, the aortoventricular junction is dilated, resulting in flattening and stretching of the leaflets.
Zone II: The Leaflets and Sinuses The parabolic shape of the leaflets (suspension bridge) allows free movement during systole and coaptation during diastole. In stenosis, the valve is frequently bicuspid, the leaflets are 1 Division of Pediatric Cardiology and Cardiac Surgery, Hope Children’s Hospital, Oak Lawn, IL, USA 2 Division of Cardiothoracic Surgery, University of Illinois, IL, USA
Corresponding Author: Chawki ElZein, Advocate Christ Medical Center, The Heart Institute for Children, 4440 West 95th Street, Oak Lawn, IL, USA. Email: [email protected]
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attenuated both in length and in depth, and the fusion of two leaflets results in eccentric valve opening. In regurgitation, the leaflet edges are usually thickened, rolled, and often stretched and flat. The root sinuses are often dilated.
Zone III: The Sinotubular Bar The sinotubular bar marks the junction with the ascending aorta. It acts as a suspension post that supports the peripheral attachment of the leaflets. In stenotic valves, the bar is restrictive, while in regurgitation it is dilated, and the intercommissural distance is increased.
Techniques of Aortic Valvuloplasty Surgical intervention should be guided by a comprehensive preand intraoperative two- and three-dimensional echocardiographic evaluation to identify the different pathologies in the three aortic root zones and tailor the technical steps accordingly.
Operative Steps: Zone I In patients with stenotic ventricular aortic junction, thorough mobilization of the subcommissural triangle is achieved by deep perpendicular incision extending proximally into the ventricular muscle and distally into the fused commissures. The incision also mobilizes the crowded and narrow area of attachment of the leaflets in both the directions along the aortic wall. Dissection of any subvalvar fibrous tissue, whether in the triangle or at the leaflet attachments, is performed (Figure 1). Reduction in the dilated junction is achieved by either internal or external annuloplasty. In the internal approach, a double row of nonabsorbable sutures is passed in and out along the perimeter of the junction. The suture is tightened over a dilator or valve sizer to achieve a diameter of þ1 to þ2 Z value (11 + 1 mm/m2). External annuloplasty on the other hand requires mobilization of the coronary arteries and the structures surrounding the root. A band of polyterafluoroethylene or other material (3-5 mm in width) is passed around the root and tightened on a sizer to achieve the desired Z value (Figure 2).
Operative Steps: Zone II Leaflet perforation is easily repaired using a patch sutured to the perimeters of the hole. Direct closure of these defects should be avoided (Figure 3). Several techniques have been used to address leaflet prolapse. A half purse-string suture, passed along the edge of the leaflet and tightened after securing its ends to the aortic wall, achieves the desired effect (Figure 4). Plication of the redundant leaflet and resuspension of the plicated segment to the aortic wall can also be used as an alternative, provided that the leaflet does not become distorted (Figure 4). Another option is resection of a triangle wedge of the prolapsed cusp. Implantation of chordae on the prolapsing leaflet has been described.3 Commissural fusion has to be completely relieved. The incision is extended into the aortic wall on both sides of the
Figure 1. Extended commissurotomy with complete relief of leaflet fusion and mobilization of the subcommissural triangle.
commissure to mobilize the leaflet and the subcommissural triangle.4 The thickened and rolled leaflet edges are thinned out and nodules shaved. Bicuspid valves with eccentric openings are tricupidized to achieve a central opening (Figure 5).5-8 Attenuated leaflets or leaflets without adequate commissural support resulting from the extended commissuratory or tricuspidization are augmented with patch material to achieve the normal leaflet configuration (Figure 6). The patch is tailored to fit the depth and length of the leaflets (Figure 7).8 The extent of augmentation should not be excessive to avoid crowding of the root and is based on direct relationship between the intercommissural distance and the leaflet dimensions (Figures 8 and 9).9 Management of dilated aortic root sinuses is evolving. Wrapping the root externally with a semirigid cylinder (15 + 1, 5 mm/m2 at the sinuses) may halt the dilatation but would affect growth potential (Figure 10). Replacement of the dilated sinus with rigid patches may be helpful.10
Operative Steps: Zone III A stenotic or hypoplastic sinotubular bar is managed by cutting through it and enlarging the area with a patch to normalize its diameter (Z value 0-1).10 On the other hand, the dilated bar should be reduced by cutting a triangular wedge of the aortic root wall to normalize its diameter. Intussusception of the dilated sinotubular bar into a normal diameter ascending aorta has also been used.11
Results Reported short- and long-term results of aortic valvuloplasty have varied considerably. Factors that contributed to durability of the repair included anatomic features of the valve, the etiology of the valve pathology, the age at repair, and the techniques used. In a review of 316 adult patients operated on between 1995 and 2008, hospital mortality was 0.63%, and the tenyear survival was 92%. Freedom from reoperation was 81%
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Figure 2. Internal and external annuloplasty.
Figure 3. Management of leaflet perforation.
Figure 4. Techniques for repair of leaflet prolapse.
Figure 5. Tricuspidization of bicuspid aortic valve with eccentric opening. The rudimentary commissure is opened.
at ten years. Dilated aortoventricular diameter, effective cusp height, and subcommissural plication were found to contribute to repair failure.12 Luciani et al reported on singular group of 147 patients operated on between 2002 and 2011. There was no hospital mortality and three late deaths. Freedom from reoperation was 95% + 3% at eight-year follow-up.13 The longest experience in pediatric patients was reported by Polimenakos et al. Median follow-up was 14.4 years. There was no early or late death in the group. Freedom from reoperation (repair or replacement) was 60% + 7.2% at 18 years. Tricuspidization to achieve central valve orifice and absence of small ventricular aortic junction were among the factors that contributed to longer longevity of the repair.5 In a report of another large series, d’Udekem et al cautioned against tricuspidization and cusp extension because of potential occlusion of the coronary ostia by the extended cusps, a finding not reported by others.14 In the same series,
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Figure 9. Completed augmentation and resuspension of the constructed leaflets.
Figure 6. Patch augmentation of defective leaflet. The reconstructed leaflet is suspended to aortic wall.
Figure 10. External support to minimize sinus dilatation.
Figure 7. The depth and length of leaflet augmentation is based on the relationship between the intercommissural triangle and the leaflet depth.
seven-year freedom from reoperation was 80%. Infants did not fare well. Other experiences with valvuloplasty had similar long-term results.15,16 When patient matching is applied to repair versus replacement populations, repair was found to have results comparable or better than patients with bioprosthesis.17
Comments
Figure 8. Resuspension of the constructed leaflets.
The improved short- and long-term results of aortic valvuloplasty in congenital and acquired aortic valve disease are due to the improved understanding of the pathology and pathophysiology of the diseased aortic valve as well as better valve imaging techniques. Data reported from different centers have shown acceptable long-term outcomes following valvuloplasty with very low rates of morbidity or mortality. When compared with the Ross procedure, valvuloplasty provides a good alternative, especially in patients with bicuspid aortic valve or dilated ventricular aortic junction, in whom the pulmonary autograft has demonstrated early postoperative dilatation and dysfunction. Valvuloplasty improves aortic valvar function without compromising the pulmonary valve, thus leaving all other surgical options open for future use. It has a distinct advantage over tissue valve implantation, as it can be used in smaller children whose ventriculoaortic junction (annulus) is smaller than commercially available tissue or even mechanical valves.
Downloaded from pch.sagepub.com at UCSF LIBRARY & CKM on December 8, 2014
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It also does not restrict the growth of the junction as the rigid ring of the prosthetic valve does. In addition, the strut of the tissue valve can interrupt the coordinated movement of the left ventricle, aortic valve, aortic sinuses, and ascending aorta.18 These factors, combined with no need for anticoagulation, make valve repair the most optimal option in smaller children with serious valve dysfunction. Although there has been no controlled prospective study, the long-term performance of aortic valvuloplasty has been acceptable and is definitely better than that reported for tissue valves in the young population. The continued modifications and improvements in the repair techniques make comparison with the standard tissue valve insertion difficult to validate. Moreover, old valve repair techniques have tackled only one of the many pathological features of the dysfunctional aortic valve. The improved understanding of the different lesions affecting the congenital aortic valve and the holistic approach to the aortic root should certainly improve the results, especially as different centers gain experience with a large number of patients on whom a comprehensive approach to repair has been used. One of the factors that have compromised the long-term outcome of valve repair is the absence of tissue material that is optimal for valve reconstruction. In the authors’ experience, the use of autologous pericardium, whether fresh or fixed with variable concentrations of glutaraldehyde, has resulted in early disruption or hardening and calcification of the constructed leaflet. Bovine pericardium fixed with infrared waves resulted in early disruption of the repaired leaflets. Currently, the use of porcine decellularized small intestinal submucosa is favored, but short- and long-term results are lacking. Obviously, once an ideal patch is available, the valvuloplasty technique would become the procedure of choice. Another limitation to surgical valvuloplasty is the stenotic or subnormal valve ventriculoaortic junction (the annulus). In these cases, the repair might result in crowding of the root and early restenosis. The selective operative approach in which this subgroup of patients are treated with Ross or Ross/Konno procedures has decreased the failure rate of the valvuloplasty. Better understanding of the role played by the different components of the aortic root should further improve the valvuloplasty results. Data from the ongoing study of the relationship between the different dimensions of the leaflets and their commissural attachments in the normal and abnormal valve are likely to result in a more anatomic and functional valve repair. One aspect that needs further evaluation is the role of the sinus of Valsalva in valve function. Although it is well known that vortex patterns forming in the sinuses soon after systole modulate leaflet movements and ensure synchronous, homogeneous, and stress-free closure, little is known about the role of the sinuses in valve opening.19 Moreover, the degree of pathology of the sinuses in aortic valve disease is variable and relatively not well known. Therefore, a comprehensive knowledge of the pathology and function of the sinuses is needed in order to plan a sound surgical approach and achieve successful valve repair.20-22
Conclusion Surgical aortic valvuloplasty provides an excellent alternative for management of valve disease in small children. Selective approach, whereby the repair is used primarily in instances of dilated valve annulus and bicuspid valves, provides very satisfactory short- and long-term results. Further studies on the patch material used in the repair and better understanding of the pathophysiology of the aortic root may yield improved results in the future. 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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