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Ann Thorac Surg 2005;80:1622-1627
© 2005 The Society of Thoracic Surgeons
a Division of Pediatric Cardiac Surgery, The Johns Hopkins University Hospital, Baltimore, Maryland
b Division of Pediatric Cardiology, The Johns Hopkins University Hospital, Baltimore, Maryland
Accepted for publication April 26, 2005.
* Address correspondence to Dr Vricella, Division of Cardiac Surgery, The Johns Hopkins Hospital, 600 N Wolfe St, Blalock 618, Baltimore, MD 21287; (Email: lvricella{at}jhmi.edu).
Presented at the Forty-first Annual Meeting of The Society of Thoracic Surgeons, Tampa, FL, Jan 24–26, 2005.
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Abstract |
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METHODS: A retrospective clinical study was undertaken to examine results of aortic valve-sparing operations in pediatric patients at a single institution. Clinical and echocardiographic data were obtained from chart review and outpatient follow-up examination.
RESULTS: Between 1997 and 2004, 19 children underwent aortic valve-sparing root replacement. Mean age was 12.2 ± 4.4 years, and mean weight was 51.5 ± 22.9 kg. Median length of clinical follow-up was 58 months (range, 5 to 91). Fifteen of 19 patients (78.9%) had Marfan syndrome and 1 had aortic root dilation late after the arterial switch operation. Mean preoperative root diameter was 4.7 ± 0.6 cm, with an average Z score of 7.7 ± 1.9. Fourteen patients (73.7%) underwent root remodeling, whereas 5 (26.3%) had a reimplantation procedure. One patient required concomitant mitral valve repair. There was no operative mortality and only 1 reoperation for bleeding (5.3%). Median length of hospital stay was 5 days (range, 3 to 12). At latest follow-up, 3 of 19 patients (15.8%) have required late aortic valve replacement. Fifteen patients have no or mild aortic valve insufficiency, and 1 has moderate but stable valve regurgitation. No patient with a reimplantation procedure has had a reoperation or more than mild insufficiency, and no patient has suffered endocarditis or thromboembolism.
CONCLUSIONS: Valve-sparing aortic root replacement is a viable alternative to root replacement with mechanical or biological prostheses in children, and can be accomplished with minimal morbidity and mortality. Reimplantation procedures appear to have more durable results than root remodeling techniques, and should be strongly considered for pediatric patients with aortic root enlargement secondary to connective tissue disorders and other forms of congenital heart disease.
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Introduction |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
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Patients and Methods |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
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A retrospective analysis of the pediatric subgroup was undertaken after approval from the Institutional Review Board (April 24, 2004). Preoperative and intraoperative data was compiled from chart review. All patients were contacted by telephone interview or during outpatient visits to define functional class (New York Heart Association [NYHA] I to IV) and identify any subsequent cardiac intervention.
Preoperative and immediate postoperative echocardiograms were obtained from digital archives; maximal root, annular, sinotubular junction and ascending aortic diameters were measured, and the respective Z scores (based on patient height and weight) were calculated. Maximal root diameter was defined on two-dimensional echocardiography as the largest diameter measured between aortic root (annulus) and distal ascending aorta (proximal to the ostium of the right brachiocephalic artery). Aortic valve insufficiency (AI) was scored as 0 to 4+ (none, trivial, mild, moderate, or severe). Latest follow-up echocardiograms were either obtained during an apposite outpatient visit or were forwarded by the referring cardiologist. All preoperative and follow-up materials were evaluated and scored by a single echocardiographer (W.J.R.). "Adverse late events" were defined at follow-up as 3+ or 4+ AI on latest echocardiography or need for reintervention with aortic root/valve replacement.
All data are presented as mean ± SD unless otherwise specified. Actuarial freedom from adverse late events was plotted with the Kaplan-Meyer method, utilizing commercially available statistical analysis software (SPSS, Chicago, Illinois).
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Results |
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Associated connective tissue disorders were Marfan syndrome (n = 15, 78.9%), Ehlers-Danlos syndrome (n = 1), and an unspecified connective disorder (n = 1). One patient presented with the recently described association of bifid uvula, aortic root enlargement with vascular tortuosity, and hypertelorism [5]. A 13-year-old patient disclosed significant aortic root enlargement late after an arterial switch procedure. One child had an aneurysm associated with a bicuspid aortic valve.
Concomitant cardiac anomalies included patent foramen ovale (n = 10), severe mitral regurgitation (n = 1), branch pulmonary artery stenosis (n = 1), and patent ductus arteriosus (n = 2). Extracardiac anomalies included clinically significant scoliosis (n = 5), severe pectus carinatum (n = 2), and pectus excavatum (n = 3). One patient had an uneventful Ravitch-type correction of pectus deformity late after AVSRR.
A "Yacoub" or "David II" (root remodeling) technique was used in the first 6 patients in this series. The subsequent 8 patients underwent a "David III" remodeling procedure, in which the suture line along the nadir of the noncoronary sinus was reinforced with a Teflon felt strip (Impra, subsidiary of L.R. Bard, Tempe, Arizona). With the exception of an infant who underwent reimplantation within a 24-mm straight Dacron graft (David I procedure), a modified David V procedure was performed in the remaining patients. In this latter group (although it will be referred to as "David V" in this manuscript), the native aortic valve was resuspended within a commercially commercially available Dacron tube with pseudosinuses (Gelweave Valsalva graft) [6]. The distribution of graft sizes is shown in Figure 1; the majority of patients received either a 28-mm or 30-mm graft, and no specific formula was utilized in choosing diameter of aortic root replacement grafts. Mean cardiopulmonary bypass and cross-clamp times were 154 ± 26 minutes and 111 ± 25 minutes, respectively. Additional procedures included closure of patent foramen ovale (n = 10), ligation of the arterial duct (n = 2), De Vega mitral annuloplasty (n = 1), and pulmonary arterioplasty (n = 1). Two patients required revision of the right coronary anastomosis, and in 1 infant, delayed primary sternal closure was performed on the first postoperative day. During the period of the study, no pediatric patient underwent root replacement with a composite mechanical valve graft as a result of intraoperative conversion from a failed AVSRR.
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Postoperative complications included mediastinal reexploration for bleeding (n = 1, 5.3%), and pneumothorax requiring chest tube reinsertion (n = 2). Aside from 1 child requiring readmission for a pneumothorax, no short-term postdischarge complications were observed.
Intermediate-term clinical follow-up was complete for all patients and updated to December 2004. Median length of clinical follow-up for the entire cohort was 58 months (range, 5 to 91); echocardiograms were also obtained in the last 6 months of 2004 for all children who have not undergone reoperation. For these children, median length of echocardiographic follow-up was 46 months.
Actuarial freedom from adverse late events (development of 3+/4+ aortic regurgitation or need for aortic valve or root replacement) is reported in Figure 2. In Figures 3, 4, and 5, the preoperative, early postoperative, and late echocardiographic maximal aortic root diameters are outlined as they relate to the different techniques utilized. Three of 19 patients (15.8%) required late mechanical aortic valve replacement; in 2 patients, simultaneous chordal sparing mitral valve replacement was performed. Cause of late aortic regurgitation was annular dilation and cusp prolapse in all 3 cases. All 3 patients had undergone AVSRR with a root remodeling technique, partially reinforced with a Teflon strip (David III modification) in 2 patients. Of the remaining 16 patients, only 1 has stable 3+ AI at latest follow-up after root remodeling; all others were found to have trivial (n = 9), mild (n = 3) or no (n = 3) aortic insufficiency.
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Comment |
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Aortic root aneurysms in children carry the same risks as in adults, namely rupture, dissection, and loss of valvular competence. However, the risks of these complications as they relate to aneurysm size and the optimal timing for intervention have never been precisely defined in children as they have been in adults. In extrapolating from data available in adult literature, weight should be given to absolute maximal root diameter and its progression over time [7]. It has been our practice to advise root replacement when the aortic diameter exceeds 5.0 cm, when enlargement increases at a rate greater than 1.0 cm per year, or if valvular insufficiency progresses [8]. In patients younger than 12 years, indications are even less defined. Incidence of rupture and dissection in very young patients is in fact low, as these catastrophic events tend to occur in the late teenage years. In a meta-analysis of 286 patients aged less than 20 years with Marfan syndrome, Knirsh and coworkers [9] reported aortic dissection in 5 patients (1.7%) and rupture in 3 (1.0%). All but 1 patient (14 years old) were 19 years of age at the time of the acute event involving the aortic root [9]. Aortic catastrophe nevertheless remains an important cause of death in untreated patients, followed by the sequelae of chronic valvular incompetence. For younger children and infants, strong consideration should therefore be given to elective replacement in case of giant root enlargement. A lower threshold to intervene is also reasonable in case of progressive valvular insufficiency, ventricular enlargement, family history of aortic dissection/rupture or onset of symptoms [10].
Aortic root replacement with a composite mechanical valve graft has been the "gold standard" of care in young patients for several decades. In pediatric patients whose annulus can accommodate a mechanical prosthesis (with or without concomitant root enlargement procedures) root replacement has been accomplished with safety and long-term durability [8, 10]. Excellent operative and long-term survival has been reported, with actuarial freedom from adverse aortic events (thromboembolism, endocarditis, reoperation) at 20 years better than 70% [11, 12].
Aortic valve preservation offers intuitive and important advantages over the Bentall procedure, although its durability awaits confirmation by analysis of long-term data. Avoidance of anticoagulation and a low incidence of endocarditis and thromboembolism have been reported [3, 13], but improved freedom from late reintervention and annular dilation with valvular incompetence remain unproven. As summarized eloquently by Miller [14], most of the numerous technical variations of AVSRR reflect the quest for a technique that secures both valve preservation and protection from late recurrent root enlargement. We have initially used a remodeling technique with scalloped "Dacron tongues" because of the theoretical advantage of a more physiologic excursion of the aortic leaflets within the artificial sinuses [15–17]. However, as reported by other authors [13, 18], we observed a trend toward late root/annular enlargement as probable consequence of retained abnormal native tissue near the valve hinge points and around the commissural posts. We subsequently moved to a "supported" remodeling technique with Teflon strip reinforcement and, eventually, to root reimplantation. Since May 2002, we have almost exclusively utilized a commercially available graft with prefabricated pseudosinuses. This graft combines the advantages of root remodeling (preservation of physiologic leaflet excursion) with those of reimplantation (root support below the nadir of the sinuses of Valsalva and superior hemostasis), and we speculate that greater freedom from late valve failure and root replacement will be observed when long-term data become available. We currently reserve valvar resuspension within a straight Dacron conduit only for children with aortic root external diameter measuring less than 24 mm, this being the smallest size of commercially available grafts with pseudosinuses.
Patient selection plays as important a role as does surgical technique with regard to late outcomes. In a previous report from our institution [3], a 4.5-fold increase in significant (3+/4+) late AI was noted in patients who had preoperative moderate to severe AI (3+ to 4+). When this degree of regurgitation is present and is due to asymmetric cusp prolapse or multiple leaflet fenestrations, a more conventional Bentall-type approach may be preferable. Aortic valve preservation should be attempted in the presence of a competent and nonstenotic bicommissural valve [19, 20], and considered when a simple repair technique (for example, free-margin shortening) can restore competency. If transesophageal echocardiography reveals moderate regurgitation upon weaning from cardiopulmonary bypass, the native aortic valve is excised, and a mechanical prosthesis can be easily and expeditiously inserted in the subcoronary position.
Three patients required aortic valve replacement due to late valvular regurgitation. A 10-year-old girl underwent aortic commissuroplasty at the time of AVSRR, and although her initial postoperative echocardiogram disclosed only mild regurgitation, she progressed to aortic valve replacement 26 months postoperatively; a 1-year-old child with trivial regurgitation in the early postoperative phase had progressive aortic and mitral regurgitation and required combined mitral and aortic valve replacement with root enlargement 57 months after the initial procedure. A third patient with initial mild aortic regurgitation had progressive root dilation with severe AI and mitral regurgitation, and underwent aortic and mitral valve replacement 31 months after AVSRR. All 3 patients initially underwent AVSRR with a root remodeling technique, reinforced with Teflon strips in the latter 2 patients. No patient with a reimplantation procedure using a Gelweave Valsalva graft has had progression of AI or need for reintervention.
At latest follow-up, 2 patients are in NYHA functional class II; 1 child has undergone late aortic and mitral replacement, while the second is developing progressive mitral regurgitation and is currently being evaluated for mitral valve repair. All other patients (89.5%) currently enjoy unrestricted physical activity.
In conclusion, valve-sparing aortic root replacement can be accomplished in pediatric patients with congenital heart disease or connective tissue disorders with minimal morbidity and mortality. Valve preservation and annular stabilization provided by aortic valve reimplantation within a graft with pseudosinuses may prove to be the most durable alternative to composite prosthetic replacement in children.
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Discussion |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
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DR VRICELLA: I don't think I would repair a pectus deformity simultaneously. In our case, the repair was undertaken several years after the initial aortic root replacement.
DR KANTER: In our patient we separated the operations by a year.
DR VRICELLA: Most of these patients were followed with either some degree of aortic regurgitation or root enlargement, and those were in our view the most pressing clinical issues. I would find it probably easier to address the aneurysm first and then, after recovery, correct the pectus deformity with a conventional repair rather than a Nuss procedure.
DR KANTER: The second group of patients who we've had difficulty with are the rare patients with an enlarged ascending aorta and a bicuspid aortic valve. Did any of the patients in this series have bicuspid valves and, if so, how did you manage them?
DR VRICELLA: Only 1 patient in this series had a bicuspid aortic valve. I think that if the valve is competent and does not show any significant deterioration, it can be preserved. Preserving a competent valve with possible long-term competency is still a valid alternative to a composite valve graft.
The groups in Germany have reported a remarkable experience with reimplantation or remodeling of roots with bicuspid aortic valves, with good intermediate-term results. So we would not regard the presence of a competent bicuspid aortic valve as a contraindication to valve preservation.
DR MARSHALL L. JACOBS (Philadelphia, PA): My compliments to you on a very, very fine presentation and to you and your group and, of course, to Duke Cameron on really leading the effort in applying these techniques to children.
The most interesting I thought of your slides showed the patient-by-patient evolution from the degree of aortic insufficiency by echo preoperatively to most recent follow-up. And as you flashed on the last portion, you revealed that 1 of the patients preoperatively had 3+ aortic regurgitation. And if the height of the column between 2 and 3 indicated some quantitative difference, there were a lot of 2.5+ or something of that sort.
In choosing between the valve-sparing technique and the composite root replacement, what factors give you the confidence in the setting of 2.5+ or 3+ aortic insufficiency in the preop status to predict that you'll be able to spare the valve and wind up with competence?
DR VRICELLA: Thank you for your comment, Dr Jacobs. With regard to the first part of your question, the Y axis of the graph simply categorized the degree of preoperative aortic regurgitation as 2+, without further subdividing the patients with mild AR.
With regards to the issue of when not to do the operation, one must understand that even when they present with very large aneurysms, the vast majority of patients with Marfan syndrome don't typically have a lot of aortic regurgitation. Extrapolating from the experience with adult Marfan patients, more than 90% of pediatric patients should present with no more than mild aortic regurgitation in the setting of significant aortic root enlargement. I think that if you can restore good coaptation of the leaflets, and if there's no major valvar abnormality you should proceed with a valve sparing procedure, reserving composite valve-graft replacement to those cases with asymmetric prolapse or in which competency cannot be restored by simple additional techniques such as shortening of the free margin.
With transesophageal echocardiography, we are of course immediately able to assess competency of the valve shortly after releasing the aortic cross-clamp. If there is more than 2+ aortic regurgitation, we'll simply rearrest the heart, transect the graft, excise the valve, and implant a mechanical prosthesis in the subcoronary position. If we are concerned about bleeding, we then proceed to a root replacement with a composite valve-graft.
DR HENRY L. WALTERS III (Detroit, MI): I enjoyed your series. This is a follow-up on Dr Jacob's question concerning a technical issue. You're using a graft that mimics the aortic sinuses. How do you match the native commissures and the remnant of the aortic wall that you leave behind to the height of the new sinotubular junction that is incorporated into the prosthetic graft? It seems to me that the matching of those structures would have to be just perfect in order to avoid the development of aortic insufficiency. I'm sure that you have a way of estimating this intraoperatively. Also, do you have a way of altering the prosthetic graft with the incorporated sinuses of Valsalva to obtain this ideal fit with the remnant of the native aortic root?
DR VRICELLA: Actually, a lot of patients with Marfan syndrome have very high commissural posts and deep sinuses. The question then is: how do you reimplant the posts high enough so that you can still maintain leaflet coaptation by preserving the geometry of the sinotubular junction and the height of the posts?
These grafts are not sized by height but only by diameter. Whereas in the other techniques (such as the David V technique), the graft is plicated proximally and distally and its height fashioned by the surgeon, with commercially available grafts with pseudosinuses the surgeon picks the size of the proximal and distal anastomosis, but cannot adjust the height of the sinuses. We have found this to be actually fairly forgiving in terms of being able to match the reimplantation suture line to the height of the graft. By stretching the graft and compensating with the running suture line we have found this not to be a problem with regards to height of the posts, apposition of the leaflets, and hemostatic quality of the proximal suture line.
DR E. DEAN MCKENZIE (Houston, TX): Did any of your patients have a bicuspid valve? And if not, what will be your recommendation with a healthy appearing bicuspid valve that's regurgitant because of anular dilation?
DR VRICELLA: This is a follow-up from the previous question. One patient in this series had a bicuspid valve. If the valve is otherwise competent and pliable, we would definitely pursue aortic valve-sparing root replacement.
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Acknowledgments |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
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References |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
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