The rheumatic mitral valve and repair techniques in children

Abstract

The mitral valve is the most commonly affected valve in acute and chronic rheumatic heart disease in the first and second decades of life. Pure or predominant mitral regurgitation with non-significant stenosis (mitral valve area > 1.5 cm(2) on echocardiography) is the most frequently encountered valvular dysfunction in children. In our experience, based on 428 children operated between 1993 and 2011 at our institution, functional classification based on leaflet motion assessed by echocardiography and reconfirmed peroperatively revealed pure annulus dilatation (type I) in 7% of patients, anterior leaflet prolapse (type IIa) in 33%, combination of anterior leaflet pseudoprolapse with restricted motion of the posterior leaflet (type pseudoIIa/IIIp) in 34%, and restricted anterior and posterior leaflet motion (type IIIa/p) in 26%. Patients with type III were older than those with type IIa and type pseudoIIa/IIIp. Different techniques can be used to repair rheumatic mitral valve lesions: prolapse of the anterior leaflet caused by chordal elongation or rupture can be treated by chordal shortening, chordal transfer, or artificial chordal replacement; restricted motion of the anterior and/or posterior leaflet can be treated by commissurotomy, splitting of the papillary muscles, resection of the secondary, or sometimes primary posterior chordae, posterior leaflet free edge suspension, leaflet thinning, and leaflet enlargement using autologous pericardium. Because mitral annulus dilatation is present in almost all patients with mitral regurgitation, concomitant ring annuloplasty offers more stability in valve repair, improving long-term outcome. The major causes for failure of rheumatic mitral valve repair are the presence of ongoing rheumatic inflammation at the time of surgery, use of inappropriate techniques, technical failures requiring early reoperation, lack of concomitant ring annuloplasty, and progression of leaflet and chordal disease further resulting in more leaflet retraction, thickening, and deformity. Freedom from reoperation depends on mitral regurgitation functional type, the type IIa and type pseudoIIa/IIIp having a better long-term outcome than type I and type III, in our series. In conclusion, mitral valve repair should be a preferred strategy in children with rheumatic heart disease whenever feasible, providing stable actuarial survival with fewer thromboembolic complications in a pediatric population noncompliant to anticoagulation.