SURGICAL APPROACHES FOR DOUBLE-OUTLET RIGHT VENTRICLE OR TRANSPOSITION OF THE GREAT-ARTERIES ASSOCIATED WITH STRADDLING ATRIOVENTRICULAR VALVES

The surgical management of patients with double-outlet right ventricle or transposition of the great arteries and straddling atrioventricula r valves remains a subject of controversy. Biventricular repair has th eoretic advantages because it establishes normal anatomy and physiolog y. In some instances, however, it seems to carry too high operative ri sk, and a univentricular heart repair is preferred. Since 1984, we hav e operated on 34 patients with double-outlet right ventricle (n = 15) or transposition of the great arteries (n = 19) with isolated straddli ng tricuspid valve (n = 17), isolated straddling mitral valve (n = 9), both mitral and tricuspid straddling (n = 2), or abnormal insertion o f tricuspid (n = 7) or mitral (n = 2) chordae in the left ventricular outlet, precluding an adequate tunnel construction. Straddling was cat egorized according to the location of the papillary muscle insertion i n the opposite ventricular chamber: type A, on the edge of the ventric ular septal defect (n = 14); type B, on the opposite side of the ventr icular septum away from the edge of the defect (n = 8); type C, on the free wall of the opposite ventricular chamber (n = 8). Abnormal chord al insertions were classified according to the location of their attac hments around the edges of the defect. Three types of chordal distribu tion were identified: on the aortic conus, on the pulmonary conus cros sing the ventricular septal defect, or around the defect closing it li ke a curtain. All but three patients had two ventricles of adequate si ze. Sixteen patients underwent palliation. Median age at the definitiv e operation was 6.5 months (range 1 to 130 months). Thirty patients un derwent a biventricular repair and four had a univentricular repair. B iventricular repair was achieved by an arterial switch operation in 18 patients and by tunnel construction from the left ventricle to the ao rta in 12. In isolated straddling of types A and B, the ventricular se ptal defect was closed by adjusting the septal patch on the ventricula r side above the straddled papillary muscle. In type C, the patch was sewn over the papillary muscle by applying it on the septum. In double straddling, the ventricular septum was incised between the two papill ary muscles, and an ellipsoid patch was used to reconstruct the septal defect, directing each subvalvular apparatus into its own ventricular chamber. When the abnormal chordae in the left outflow tract inserted on the aortic or pulmonary conus, the conus was incised and tailored to make a flap, leaving an unobstructed left ventricular outflow tract . In two patients the subvalvular apparatus was resected and reattache d to the patch, Curtainlike chordae were a contraindication to biventr icular repair in double-outlet right ventricle but not in transpositio n, There were four early deaths and one late death, all occurring in t he group having biventricular repair, Death was due to myocardial isch emia (n = 1), right ventricular hypoplasia (n = 1), pulmonary hyperten sion (n = 1), and residual subaortic stenosis (n = 1). Two patients ha d moderate to severe postoperative atrioventricular valve incompetence , caused by a cleft in the mitral valve in one patient. Three patents were reoperated on for subaortic stenosis (n = 1), pulmonary stenosis (n = 1), and mitral regurgitation (n = 1). Mean follow-up of 30.7 +/- 19.4 months was achieved in the survivors. All but one patient (univen tricular repair) were in New York Heart Association class I, without a trioventricular valve incompetence. Actuarial survival at 4 years was 85.3% +/- 3%. We conclude that straddling or abnormal distribution of chordae tendineae of the atrioventricular valves does not preclude biv entricular repair in double-outlet right ventricle or transposition of the great arteries provided that the ventricles are of adequate size. Curtainlike abnormal tricuspid chordae remain a contraindication to b iventricular repair in double outlet right ventricle.