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Ann Thorac Surg 1996;61:1355-1358
© 1996 The Society of Thoracic Surgeons

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Original Articles: Cardiovascular

Aortic Valve Repair and Replacement After Balloon Aortic Valvuloplasty in Children

Division of Cardiothoracic Surgery and Pediatric Cardiology, Departments of Surgery and Pediatrics, University of Utah and Primary Children's Medical Center, Salt Lake City, Utah

Accepted for publication December 19, 1995.

	Abstract

Top Footnotes Abstract Introduction Material and Methods Results Comment Acknowledgments References

 
Background. Little is known about the incidence, indications, and results of surgical repair or replacement of the aortic valve after balloon aortic valvuloplasty (BAV) for congenital aortic stenosis in children. This study was designed to evaluate patterns of failure requiring operation after BAV for congenital aortic stenosis and to review our experience with successful repair, rather than replacement, of selected aortic valves after BAV.

Methods. From March 1986 to June 1995, 60 patients with congenital aortic stenosis aged 1 day to 27 years (mean plusmn; standard deviation, 7.3 plusmn; 6 years) underwent BAV. Twenty-three patients (38%) required operation a mean of 44 plusmn; 37 months (range, 1 to 110 months) after BAV, because of severe aortic insufficiency in 13 patients and recurrent or residual aortic stenosis in 10 patients. Severe aortic insufficiency was invariably due to avulsion of a cusp from the annulus, with resulting cusp prolapse and insufficiency. Operative intervention consisted of valve replacement in 14 patients and valve repair in 9 patients. Repair techniques included reattachment of an avulsed cusp to the aortic annulus, relief of commissural fusion, and debridement of thickened cusps.

Results. Actuarial freedom from surgical intervention after BAV was 88% plusmn; 4% at 1 year, 70% plusmn; 6% at 5 years, and 51% plusmn; 12% at 9 years. The need for aortic valve operation was unrelated to age at the time of BAV, indication for operation (aortic insufficiency versus aortic stenosis), age at operation, or preoperative gradient. All patients survived aortic valve operation; there was one late death at an average follow-up of 27 plusmn; 20 months (range, 2 to 61 months) after aortic valve operation. Stenosis was well relieved in all patients undergoing valve replacement. The 9 valve repair patients have been followed for 22 plusmn; 14 months (range, 1 to 47 months). Echocardiographic follow-up of the valve repair patients revealed a mean residual aortic stenosis peak instantaneous gradient of 32 mm Hg and mild aortic insufficiency or less in all patients.

Conclusions. Aortic valve operation is required in 5% to 7% of patients yearly after BAV. The need for operation appears to be unrelated to age at the time of BAV; aortic insufficiency predominates over aortic stenosis as an indication for operative intervention. Valve repair can be applied in some patients after BAV with good intermediate-term results and may delay the need for aortic valve replacement.

	Introduction

Top Footnotes Abstract Introduction Material and Methods Results Comment Acknowledgments References

 
Balloon aortic valvuloplasty (BAV) is a widely accepted treatment modality, and in many institutions it represents the primary treatment for children of all ages with congenital valvar aortic stenosis [1–4]. Early results are good, but a number of patients experience an in crease in aortic insufficiency or recurrent or residual aortic stenosis [3]. The need for aortic valve operation after BAV is relatively unknown. The growing infant or child who requires a subsequent aortic valve operation presents a challenge for the surgeon to provide a treatment that ideally will allow annular growth and not require anticoagulation therapy. Valve repair has been described in preliminary form after BAV [5, 6] and can meet these challenges for children who require subsequent surgical intervention.

For editorial comment, see page 1297.

Since 1990, we have selectively used surgical valvuloplasty techniques to repair the aortic valve when surgical intervention is required after BAV. From this experience, we have determined the time-related incidence of failure after BAV and the need for operation on the aortic valve. We describe our techniques for aortic valve repair and the intermediate-term results using both valve repair and replacement after BAV in children.

	Material and Methods

Top Footnotes Abstract Introduction Material and Methods Results Comment Acknowledgments References

 
Patients
All patients who underwent BAV for isolated congenital aortic stenosis from March 1986 until June 1995 at Primary Children's Medical Center were reviewed retrospectively. Patients with subaortic stenosis, supravalvar aortic stenosis, or mixed forms of left ventricular outflow tract obstruction were excluded from the study. Patients who had undergone a previous open valvotomy and subsequently required BAV were included. Balloon aortic valvuloplasty was performed using standard techniques and with early results that have been described previously in detail [3]. These patients were then followed clinically and with two-dimensional and Doppler echocardiography for late development of important aortic valve insufficiency or stenosis. Standard indications were used to refer patients for operation, including a residual or recurrent peak-to-peak aortic outflow gradient greater than 60 mm Hg by Doppler echocardiography or the onset of severe aortic valve regurgitation. Patients who subsequently required surgical intervention on their aortic valve formed the study group.

Operative Technique
The surgical approach was individualized for each patient to treat aortic valve insufficiency or stenosis that occurred after BAV. Standard cardiopulmonary bypass techniques and retrograde coronary sinus cardioplegic arrest were used routinely. Aortic valve replacement was performed using a prosthetic valve, an allograft valve, or a pulmonary autograft. Surgical repair of the valve was undertaken at the surgeon's discretion and judgment. The aortic valve was inspected, and any cusp dehiscence was treated by reattachment of the torn leaflet to the annulus using interrupted monofilament suture (Fig 1). Residual commissural fusion was then relieved using standard aortic valvotomy techniques by incising the commissural fusion back to the annulus (Fig 2A). Rudimentary commissures in bicuspid valves were not incised if commissure support was lacking and cusp prolapse would likely result. Thinning of dysplastic aortic valve leaflets or removal of dysplastic nodules was performed whenever possible (Fig 2B).

View larger version (92K): [in this window] [in a new window]   Fig 1. . Pathologic process and repair of aortic insufficiency after balloon aortic valvuloplasty in a patient with a bicuspid valve. In patients with severe aortic insufficiency, typically there is avulsion of one cusp from the annulus with resulting cusp prolapse (A). Repair in this situation involves reattachment of the avulsed leaflet to the annulus using interrupted monofilament suture (B).

View larger version (106K): [in this window] [in a new window]   Fig 2. . Relief of aortic stenosis after reattachment of an avulsed cusp following balloon aortic valvuloplasty. Commissural fusion is relieved by sharp valvotomy to the annulus (A) and debridement and thinning of dysplastic leaflets (B).

Statistical Methods
Patient survival and event-free survival were determined according to the actuarial method of Kaplan and Meier [8]. Multiple stepwise logistic regression analysis was performed using the S plus statistical program (Stat Sci, Inc, Seattle, WA) to determine which of seven preoperative patient characteristics were predictive of valve repair rather than valve replacement. The factors considered included patient age at the time of BAV, patient age at the time of aortic valve operation, preoperative left ventricular outflow gradient, primary indication for operation (aortic stenosis or aortic valve insufficiency), interval between BAV and aortic valve operation, and the year of aortic valve operation. Unless otherwise noted, all values are reported as mean plusmn; standard deviation.

	Results

Top Footnotes Abstract Introduction Material and Methods Results Comment Acknowledgments References

 
From March 1986 until June 1995, 60 patients underwent BAV for isolated congenital aortic stenosis. Ages at the time of BAV ranged from 1 day to 27 years (mean, 7.3 plusmn; 6 years). Overall, 23 patients (23 of 60, 38%) underwent an aortic valve operation after BAV. Two of these 23 patients had undergone an aortic valvotomy before BAV. Ages of the patients at the time of aortic valve operation ranged from 4 months to 21 years (mean, 11.8 plusmn; 6.4 years), and the interval between BAV and aortic valve operation was 35 plusmn; 28 months (range, 1 to 110 months). The need for aortic valve operation was relatively linear over time; the freedom from aortic valve operation after BAV is represented in actuarial form in Figure 3.

View larger version (17K): [in this window] [in a new window]   Fig 3. . Actuarial freedom from aortic valve operation after balloon aortic valvuloplasty (BAV) in 60 patients.

All patients survived aortic valve operation; there has been one late death in an infant 3 months after aortic root replacement with a homograft. The remaining survivors have been followed for an average of 27 plusmn; 20 months (range, 2 to 61 months) after aortic valve operation; specifically, valve repair patients were followed 22 plusmn; 14 months, and valve replacement patients for 27 plusmn; 21 months. Late echocardiograms have been obtained in all patients to determine left ventricular function, left ventricular outflow gradient, and the degree of aortic valve insufficiency. The patients undergoing valve replacement showed a mean late Doppler echocardiographic gradient of 24 plusmn; 9 mm Hg and only trivial aortic valve insufficiency. The patients undergoing repair of the aortic valve demonstrated a mean Doppler echocardiographic gradient of 32 plusmn; 10 mm Hg (range, 25 to 45 mm Hg) at late follow-up, with mild aortic valve insufficiency (1+ to 2+) in 7 patients and trivial aortic valve insufficiency (none to 1+) in 2 patients. No operative or balloon reinterventions have been required to date in either the valve repair or replacement patients.

Multiple stepwise logistic regression analysis was performed to determine factors associated with a successful valve repair rather than valve replacement. The most important factors included a shorter interval between BAV and aortic valve operation (p = 0.02) and a more recent year of operation (1991 to 1995) (p = 0.03). The primary indication for operation (aortic insufficiency or aortic stenosis) (p = 0.30), preoperative left ventricular outflow gradient (p = 0.52), age at BAV (p = 0.97), and age at aortic valve operation (p = 0.97) were not associated with the ability to repair the valve.

	Comment

Top Footnotes Abstract Introduction Material and Methods Results Comment Acknowledgments References

 
Balloon aortic valvuloplasty has emerged over the last decade as the procedure of choice in many centers for the treatment of isolated congenital aortic stenosis [1–4]. The rationale for the use of BAV instead of operative valvotomy has included avoidance of an operative procedure, lower mortality rate in infants, and a comparable incidence of late aortic valve insufficiency or stenosis. These reasons are certainly controversial, and it is beyond the scope of this study to attempt to answer the question of the advantages or disadvantages of BAV compared with valvotomy. Rather, we have attempted to look at the need for aortic valve operations after BAV and the possibility of aortic valve repair in selected patients. From this study, we have found a relatively linear relation between the need for aortic valve operation and time after BAV, implying that aortic valve operation is not a phenomenon that occurs only early after BAV (see Fig 3). Aortic valve repair appears possible and in the short term seems to offer a viable alternative to valve replacement with either a prosthetic, allograft, or autograft valve.

Early results with BAV appear to be good, with a 40% to 60% gradient reduction and an incidence of immediate and late aortic valve insufficiency of 15% to 30% [1–4]. At first glance, this study appears to have a higher incidence of failure and need for aortic valve operation than previously reported studies. Others have reported an incidence of late aortic valve repair or replacement of 10% to 17% [3–6], in contrast to the incidence of 38% in this study. However, the first aortic valve operation in this series did not take place until June 1990, more than 4 years after the first BAV procedure, which emphasizes the importance of long-term follow-up in determining the true incidence of late aortic valve operations. Presentation of time-related events in valve operations in a raw form underestimates the true incidence; such events should be presented in an actuarial form, as we have in this study [9, 10]. The relatively higher incidence of operative intervention after BAV in our series may also be partially explained by our relatively aggressive approach to both recurrent and residual aortic stenosis and substantial aortic valve insufficiency. Our approach to recurrent aortic stenosis has been operative intervention rather than repeat BAV, as others have reported [4]. We believe that if aortic stenosis is unrelieved or recurrent after initial BAV, then a second balloon procedure is less likely to succeed, and thus we proceed directly to operation. We have also elected to perform aortic valve operation in patients with pronounced aortic regurgitation and left ventricular dilatation or decreased systolic function, even in the absence of symptoms. The proper timing of aortic valve operation in children with aortic valve insufficiency is difficult and somewhat controversial.

In most series, the pathologic process seen after BAV demonstrates aortic insufficiency predominating over residual aortic valve stenosis. Typically for patients with severe aortic insufficiency, there is avulsion of a cusp from the annulus with varying degrees of cusp prolapse [7, 11]. In addition, a tear in the aortic wall can result, with intimal dissection or even annular disruption [12]. Sholler and associates [4] found that substantial aortic insufficiency was 21% when a balloon to annulus ratio greater than 1.0 was used, compared with 11% when a ratio of less than 1.0 was used. Others also have found that this complication can be minimized, but not eliminated, by the use of a balloon to annulus size ratio of 0.8 to 1.0 [3, 11]. Recurrent or residual stenosis after BAV is usually due to valve morphology, with either a severely dysplastic or unicommissural valve resulting in an inability to achieve a commissural tear and adequate valvuloplasty [4]. We found that reattachment of a torn leaflet to the annulus often ``recreates'' the stenosis that was originally present with typical commissural fusion. Unless there is severe retraction of the leaflet tissue, the narrowing often can be relieved by performing a commissurotomy in the usual position and depth. Because severe insufficiency was invariably associated with a torn cusp, which can be seen with two-dimensional echocardiography [7], we recommend early referral for operative repair. This may avoid increased cusp retraction and shortening of torn leaflets with time, so the valve may be repaired rather than replaced.

It must be emphasized that our follow-up of aortic valve repair after BAV was relatively short, and it is possible that late failure of the valve repair can occur. Surgical aortic valvotomy for congenital aortic stenosis has a defined success rate in children that approximates an 80% to 90% freedom from reoperation at 10 years [13–15]. We speculate that valve repair or valvotomy for relatively pure aortic stenosis after BAV would have nearly the same success rate as an initial aortic valvotomy. Furthermore, aortic valve repair in the setting of a previous BAV and severe aortic regurgitation has an unknown longevity. However, with intermediate-term follow-up averaging 22 months, there have not been any late failures due to increased gradient, and residual aortic valve insufficiency seems to be minimal and has not been progressive.

The emergence of the pulmonary autograft procedure certainly raises the issue of the best procedure for the child who needs aortic valve operation after failed BAV. Elkins [16] believes that a pulmonary autograft procedure is clearly the best choice for recurrent aortic stenosis and may be the best procedure for congenital aortic stenosis, even for the first operation. Although we previously performed a large number of prosthetic valve replacements, our current approach is to select a pulmonary autograft as the first choice when valve replacement is necessary in the young child who requires operation after BAV. However, we would select valve repair over any type of valve replacement if valve repair can be accomplished with a good reduction in left ventricular gradient and reduction of aortic insufficiency to acceptable levels. Only with long-term follow-up and further experience with both pulmonary autograft procedures and aortic valve repair will we be able to determine the best approach to aortic valve operations for children after BAV.

	Acknowledgments

Top Footnotes Abstract Introduction Material and Methods Results Comment Acknowledgments References

 
We thank Marlene Eggers, PhD, of the Department of Biostatistics, University of Utah, for assistance with statistical analysis.

	Footnotes

Top Footnotes Abstract Introduction Material and Methods Results Comment Acknowledgments References

 
Presented at the Thirty-first Annual Meeting of the American College of Cardiology, New Orleans, LA, Mar 19–23, 1995.

Address reprint requests to Dr Hawkins, Cardiothoracic Surgery, Primary Children's Medical Center, 100 North Medical Dr, Salt Lake City, UT 84113.

	References

Top Footnotes Abstract Introduction Material and Methods Results Comment Acknowledgments References

 

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This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): John A. Hawkins Edwin C. McGough Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hawkins, J. A. Articles by McGough, E. C. Search for Related Content PubMed PubMed Citation Articles by Hawkins, J. A. Articles by McGough, E. C. Related Collections Related Article