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Subaortic stenosis in the spectrum of atrioventricular septal defects. Solutions may be complex and palliative
G S Van Arsdell1, W G Williams, C Boutin
1Division of Cardiovascular Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.
Insights
Subaortic stenosis in children with atrioventricular septal defects often requires reoperation after standard fibromyectomy. Leaflet augmentation combined with fibromyectomy may reduce the need for repeat surgeries.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease Surgery
- Cardiac Anatomy
Background:
- Subaortic stenosis (SAS) frequently coexists with atrioventricular septal defects (AVSDs) in children.
- Operative management of SAS in this population presents unique challenges due to complex cardiac anatomy.
Purpose of the Study:
- To evaluate the long-term outcomes of surgical treatment for subaortic stenosis in children with atrioventricular septal defects.
- To investigate factors influencing reoperation rates and explore potential improvements in surgical techniques.
Main Methods:
- Retrospective analysis of 19 children undergoing operative treatment for SAS associated with AVSD between 1982 and 1994.
- Review of surgical procedures, including fibrous resection, myectomy, and left atrioventricular valve procedures.
- Measurement of the angle between the outlet septum and septal crest in normal and AVSD hearts.
Main Results:
- Seven children (36.8%) required reoperation for SAS, with a 6-year actuarial freedom from reoperation of 66% +/- 15%.
- A significant difference in the outlet septum angle was observed between normal hearts and those with AVSDs (p < 0.01).
- Fibrous resection and myectomy were the primary surgical interventions for obstruction relief.
Conclusions:
- Standard fibromyectomy for SAS in children with AVSD is associated with a high rate of reoperation.
- Augmenting the superior bridging leaflet and performing fibromyectomy may decrease the likelihood of reoperation by normalizing outflow tract geometry.
Unlabelled:
From July 1982 through September 1994, 19 children had operative treatment of subaortic stenosis associated with an atrioventricular septal defect. Specific diagnosis were septum primum defects in 7, Rastelli type A defects in 6, transitional defects in 4, inlet ventricular septal defect with malattached chordae in 1, and tetralogy of Fallot with Rastelli type C defect in 1. Twenty-seven operations for subaortic stenosis were performed. Surgical treatment of the outlet lesion was performed at initial atrioventricular septal defect repair in 3 children and in the remaining 16 from 1.2 to 13.1 years (mean 4.9 years, median 3.9 years) after repair. Eighteen of the 19 children had fibrous resection and myectomy for relief of obstruction. Seven children had an associated left atrioventricular valve procedure. One child received an apicoaortic conduit. Seven children (36.8%) required 8 reoperations for previously treated subaortic stenosis. Time to the second procedure was 2.8 to 7.4 years (mean 4.9 years). Follow-up is 0.4 to 14.0 years (median 5.6 years). Six-year actuarial freedom from reoperation is 66% +/- 15%. The angle between the plane of the outlet septum and the plane of the septal crest was measured in 10 normal hearts (86.4 +/- 13.7) and 10 hearts with atrioventricular septal defects (22.2 +/- 26.0; p < 0.01). The outflow tract can be effectively shortened, widened, and the angle increased toward normal by augmenting the left side of the superior bridging leaflet and performing a fibromyectomy.
Conclusion:
Standard fibromyectomy for subaortic stenosis in children with atrioventricular septal defects leads to a high rate of reoperation. Leaflet augmentation and fibromyectomy may decrease the likelihood of reoperation.