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Ann Thorac Surg 2002;74:122-126
© 2002 The Society of Thoracic Surgeons

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Original article: cardiovascular

Konno aortoventriculoplasty in children and adolescents: from prosthetic valves to the ross operation

^a Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine, Atlanta, Georgia, USA

* Address reprint requests to Dr Kanter, Division of Cardiothoracic Surgery, Emory University School of Medicine, 1365 Clifton Rd, Atlanta, GA 30322 USA
e-mail: kkanter{at}emory.edu

Presented at the Poster Session of the Thirty-seventh Annual Meeting of The Society of Thoracic Surgeons, New Orleans, LA, Jan 29–31, 2001.

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
Background. In children with complex multilevel left ventricular outflow tract obstruction (LVOTO), the Konno aortoventriculoplasty is used to enlarge the aortic root and increase the size of the aortic valve implanted. We present our experience with the evolution of this surgical approach from prosthetic valves to the Ross operation.

Methods. Between March 1982 and July 2000, 60 patients (36 males and 24 females) had 72 Konno aortoventriculoplasties (prosthetic valve and Konno group [57 patients; redo, 12] and Ross-Konno group [15 patients]). The patients’ ages ranged from 5 days to 18 years (mean, 8.2 years). The underlying anatomic diagnoses were congenital aortic stenosis and LVOTO in 51 patients, coarctation of the aorta with bicuspid aortic valve in 13, severe aortic insufficiency associated with a ventricular septal defect in 8, interrupted aortic arch in 6, mitral stenosis in 6, atrioventricular septal defect in 5, and endocarditis in 3. There was no statistical difference in age or diagnosis between the two groups. The prosthetic valve group included 42 mechanical valves, 9 homografts, and 6 xenografts.

Results. Follow-up ranged from 10 months to 18.5 years (mean, 9.7 years) in the prosthetic valve and Konno group compared with 5 months to 3.7 years (mean, 2.1 years) in the Ross-Konno group (p < 0.05). There were 10 early deaths and four late deaths in the prosthetic valve and Konno group as compared with one early death and two late deaths in the Ross-Konno group (p = not significant). Reoperations for LVOTO and aortic valve replacement were significantly higher in the prosthetic valve and Konno group as opposed to the Ross-Konno group (16 vs 0, p < 0.05) mainly because of the biological valve and Konno subgroup. There were no statistical differences in reexploration for bleeding, pacemaker insertion, and reoperations for indications other than LVOTO and aortic valve replacement between the two groups.

Conclusions. The Konno aortoventriculoplasty is a good surgical option for complex LVOTO. Patients with a prosthetic valve and Konno carry a high rate of reoperation. Early operative results with the Ross-Konno operation seem promising.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
The combination of aortic stenosis and subaortic obstruction (multilevel left ventricular outflow tract obstruction [LVOTO]) in children poses a complex surgical problem that often requires enlargement of the aortic root at the time of aortic valve replacement (AVR). Several surgical techniques are used to enlarge the aortic annulus [1–3]. The anterior aortoventriculoplasty (Konno procedure) [1] is the most effective of these techniques.

In the past this approach has enabled the insertion of a larger prosthesis in the aortic position in young growing patients postponing reoperation due to prosthetic valve outgrowth. Clearly there are some major therapeutic limitations for the Konno AVR using mechanical or bioprosthetic valves in children. These include the risk of chronic anticoagulation, endocarditis and, most importantly, valve outgrowth or degeneration [4–6].

The theoretical reduction of these complications has made the use of the pulmonary autograft (Ross operation) an attractive option for AVR in children and young adults. Its growth potential and long-term durability are the main advantages when compared with the aortic homograft [7–9]. The increased surgical experience with the Ross operation has extended the use of the pulmonary autograft to neonates and infants. In recent years the pulmonary autograft combined with the anterior aortoventriculoplasty (the Ross-Konno operation) has emerged as an appealing treatment for the management of multilevel LVOTO [10, 11]. We present our experience with the evolution of this surgical approach with the Konno and AVR from using prosthetic valves to the Ross-Konno operation.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
Between March 1982 and July 2000, 60 children had AVR with anterior root enlargement (Konno aortoventriculoplasty). Patient data were analyzed retrospectively from hospital records and our cardiac database. Data included preoperative diagnosis, investigations, operative reports, postoperative course and follow-up.

Forty-five patients, 29 males and 16 females had a total of 57 combined Konno AVR operations using a prosthetic valve. Forty-two patients had a mechanical valve, 9 had an aortic homograft valve, and 6 had a xenograft valve. Previous aortic root enlargement using the posterior root technique as described by Manouguian and Seybold-Epting [2] had been performed in 3 patients at the first AVR. Patient age at operation ranged from 5 days to 18 years (mean, 7.3 years). There were no statistically significant differences in patient characteristics between the biological and mechanical prosthesis subgroups. Five surgeons performed all the operations on this group of patients between March 1982 and March 2000.

The second group consisted of 15 patients (7 males and 8 females) who had a combined Ross-Konno operation. Patient age at operation ranged from 7 days to 14.9 years (mean, 5.4 years), which was not statistically significantly different from the prosthetic valve and Konno group. Two of the 5 surgeons who operated on group A patients performed all 15 Ross-Konno operations between March 1997 and July 2000. During the same time only three prosthetic valve and Konno operations were performed; all three were redo Konno procedures.

The underlying anatomic diagnoses are presented in Table 1. The principal diagnosis in both groups was congenital aortic stenosis with LVOTO. Previous interventions are summarized in Table 2. Additional procedures with the Konno and AVR operation are presented in Table 3.

In patients who had a repeat Konno procedure, the ventricular septal incision was taken across the previously placed septal patch. A Dacron patch (Boston Scientific Company, Oakland, NJ) was then used to enlarge the subvalvular area as well as the aortic annulus. The new valve prosthesis was generally secured in place using pledgetted horizontal mattress sutures for stented valves and continuous sutures for homografts. When stented valves were implanted, a Dacron patch (Boston Scientific) was used to close the aortotomy with or without additional enlargement of the ascending aorta. Typically the incision in the right ventricular outflow tract was enlarged with a patch of autologous or bovine pericardium.

In Ross-Konno patients, after excising the aortic valve, the pulmonary trunk was opened distally through a transverse incision. The pulmonary valve was inspected. If normal, it was explanted as a pulmonary autograft. Then an incision across the aortic annulus into the ventricular septum was carried out as described for the prosthetic valve and Konno patients to relieve the LVOTO and to accommodate the larger pulmonary autograft. The pulmonary autograft was inserted mainly using a continuous suture technique. A homograft-valved conduit was then sewn in the right ventricular outflow tract.

The collected information was entered into a study database as either continuous or categorical variables for comparative statistical analysis. For comparison of the two groups, ² analysis and Fisher’s exact test were used when appropriate for quantitative data and the t test was used for normal variables. Time interval curves were constructed using the Kaplan-Meier product limit method. These curves were compared by using the Mantel-Cox log rank test. A probability of 0.05 or less was accepted as statistically significant.

	Results

Top Abstract Introduction Patients and methods Results Comment References

 
There were 10 operative deaths (10 of 57; 17.5%) in the prosthetic valve and Konno group compared with one operative death (1 of 15; 6.7%) in the Ross-Konno group (p = not significant). The operative mortality in the prosthetic valve and Konno group for the last 10 years has been reduced to 10% (3 of 30). Nine of 57 prosthetic valve and Konno operations (15.8%) had bleeding complications requiring reexploration compared with 1 of 15 Ross-Konno operations (6.7%) (p = NS). Five prosthetic valve and Konno patients (8.8%) had complete heart block develop that required permanent pacemaker insertion compared with 1 of 15 Ross-Konno patients (6.7%) (p = not significant). One prosthetic valve and Konno patient had a hemodynamic significant residual ventricular septal defect (1.7%).

Follow-up ranged from 10 months to 18.5 years (mean, 9.7 years) in the prosthetic valve and Konno operative survivors compared with 5 months to 3.7 years (mean, 2.1 years) in the Ross-Konno operative survivors. There were four late deaths in the prosthetic valve and Konno group compared with two late deaths in the Ross-Konno group (p = not significant). Freedom from aortic valve or left ventricular outflow tract reoperation is shown in Figure 1 for Konno and mechanical AVR, Konno and biological AVR, and Ross-Konno patients. At 10 years, freedom from reoperation for biological valves was 0 (Fig 2). For the mechanical valve patients, freedom from reoperation at 10 years was 80% and by 15 years this value had declined to 52%. There was a statistically significant difference in reoperation rate between Konno and mechanical AVR and Konno and biological AVR (p < 0.0001). There was no significant difference in patient characteristics between the biological and mechanical prosthesis subgroups. The main reason for reoperation in patients with Konno and biological valves was structural failure (7 patients). In patients with Konno and mechanical valves, indications for reoperation were valve outgrowth in 6 and prosthetic valve endocarditis in 3.

View larger version (16K): [in this window] [in a new window]   Fig 1. Percentage freedom from reoperation on the aortic valve or left ventricular outflow tract by Kaplan-Meier analysis; p < 0.0001 between mechanical and biological valves.

View larger version (14K): [in this window] [in a new window]   Fig 2. Percentage patient survival by Kaplan-Meier analysis. (NS = not significant; PV = prosthetic valves.)

	Comment

Top Abstract Introduction Patients and methods Results Comment References

 
Children with multilevel LVOTO consisting of subaortic narrowing and aortic valve stenosis may require initial palliation to relieve the critical level of obstruction. This may involve open aortic valvotomy [12] or balloon aortic valvuloplasty [13] for congenital aortic stenosis or subaortic membrane and muscle resection [14] to relieve subvalvular obstruction. Often this initial approach will achieve long-term clinical improvement despite some degree of residual stenosis or insufficiency avoiding a more extensive operation in the first years of life. This was the initial treatment in the majority of our patients with congenital aortic stenosis (Table 2).

In the past when the first option for an aortic valve substitute was a prosthetic valve, every effort was made to delay the operation as much as possible to allow for the child’s growth. The combination of subvalvular and valvular aortic stenosis may require an extensive operation including enlargement of the aortic root and aortic valve replacement. Several methods to enlarge the aortic root have been described [1–3]; one is the anterior aortoventriculoplasty described by Konno and colleagues [1] in 1975. The advantage of the Konno technique is that it addresses all levels of LVOTO (ie, the diffuse muscular subvalvar stenosis, the small aortic annulus, and the small proximal ascending aorta). This technique will achieve a larger increase of the left ventricular outflow tract compared with other techniques.

A problem seen with Konno aortic root enlargement is development of complete heart block. The incidence of pacemaker insertion after the Konno procedure in our series was 6 of 72 (8.3%). This compares with 9% to 12.5% in earlier reports [10, 15] to 0% to 6% in later reports [16, 17].

Mechanical valves for Konno and AVR work well short term, yet the potential exists for a number of complications over the long term including thromboembolism or anticoagulation-related hemorrhage, prosthetic valve endocarditis, and prosthetic valve outgrowth. Thromboembolism and hemorrhage were not seen in either our series or others with long-term follow-up [15, 16]. Prosthetic valve endocarditis [16] was the cause of one late death and three reoperations in our patients. The main cause for late reoperation was mechanical valve outgrowth in 6 children.

The advantages of bioprosthetic valves include no need for anticoagulation and superior hemodynamic performance compared with mechanical valves (especially homograft valves), yet they degenerate rapidly in children, especially on the left side of the heart [6, 15]. Degeneration was the main indication for reoperation in our subgroup of Konno and biological valves with actuarial freedom from reoperation at 10 years of 0% (Fig 1).

Operative mortality in the prosthetic valve and Konno group has declined over the 18 years of this series from 25.9% for the initial portion of the study to 10% (3 of 30) for the last 10 years. Other studies from the last 10 years have reported an operative mortality rate ranging from 16% to 22% in similar series that included patients aged less than 2 years old [18, 19]. This compares to reports of older patients where the mortality rate ranged from 4.7% to 8.3% [15, 16]. In general, operative mortality tends to be lower in Ross-Konno patients compared with the prosthetic valve and Konno patients [10, 17]. The cause might be that the Ross-Konno reports are based on more recent experience.

When we looked into the freedom from reoperation due to recurrent LVOTO or the need for redo AVR, we separated the prosthetic valve and Konno patients into two subgroups: (1) mechanical valves and (2) biological valves. At 10 years, freedom from reoperation for biological valves was 0 (Fig 1). For the mechanical valve patients, although freedom from reoperation at 10 years was 80%, by 15 years this value declined to 52% mainly because of valve outgrowth and prosthetic valve endocarditis. Thus in children undergoing a Konno procedure, the long-term reoperation rate is prohibitive for biological valves, and even for mechanical valves it is not inconsequential (Fig 1).

In recent years the pulmonary autograft has emerged as an attractive valve substitute for AVR, particularly in younger children. It has low thrombogenicity, low risk for infection, excellent hemodynamic performance and even growth potential with long-term durability [7–9]. With the experience gained from using prosthetic valves with the Konno aortoventriculoplasty, it was a natural evolution to use the pulmonary autograft with an anterior aortoventriculoplasty (Ross-Konno procedure) with excellent results in patients beyond the neonatal period [10, 11, 17]. Unfortunately, the urgent neonatal Ross-Konno operation still carries a high mortality rate [11]. Clearly, with the experience gained from the prosthetic valve and Konno operation, our early experience with the Ross-Konno operation has been favorable. During our follow-up there were two late deaths. Both deaths resulted from infectious complication in patients with DiGeorge syndrome. Both patients were born with interrupted aortic arch and severe LVOTO treated with a neonatal Norwood procedure followed by a bidirectional Glenn anastomosis and finally a Ross-Konno operation as a biventricular repair. This approach to interrupted aortic arch and severe LVOTO does not represent the typical patient undergoing a Ross-Konno operation in our series. Certainly the immunodeficiency combined with extensive surgical interventions increased the morbidity and mortality in this group.

The significant difference in reoperations between the prosthetic valve and Konno group and the Ross-Konno group of patients was mainly because of the greater number of reoperations in the biological AVR and Konno group. There was no difference between mechanical AVR and Konno and the Ross-Konno groups as far as reoperation to date, because the mean follow-up of the Ross-Konno group is significantly shorter at 2.1 years.

In conclusion, the Konno procedure in children is an effective option for enlargement of the left ventricular outflow tract in the face of multilevel obstruction. Morbidity tends to be higher with prosthetic valves compared with pulmonary autografts (the Ross-Konno operation) in neonates and infants. On follow-up, biological valves uniformly require reoperation, and by 15 years almost half of the mechanical valves need to be replaced. Early results with the Ross-Konno operation are promising, although data concerning long-term outcome are lacking. We believe that with increased experience the results of the neonatal Ross-Konno operation will improve significantly.

	References

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This Article Abstract Full Text (PDF) 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): Eldad Erez Kirk R. Kanter Vincent K.H. Tam Willis H. Williams Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Erez, E. Articles by Williams, W. H. Search for Related Content PubMed PubMed Citation Articles by Erez, E. Articles by Williams, W. H. Related Collections Congenital - acyanotic