Partial atrioventricular canal defect: the early and late results of operation.

Thirty-five patients underwent repair of a partial atrioventricular canal defect and have been followed for a mean of 8 years. Seventeen patients had either moderate or severe mitral incompetence prior to operation. The mitral valve was treated as a bileaflet structure. The cleft in its anterior leaflet was closed in each patient in whom the valve was incompetent. The septal defect was closed with pericardium, and the coronary sinus was left on the right atrium. Two patients required reoperation, 1 to close a recurrent septal defect and 1 to replace a mitral valve that had been competent for the first several years after the initial repair. All 33 survivors remain in New York Heart Association Functional Class I. Nineteen patients have no mitral incompetence, and the remaining 14 have only mild incompetence. These data demonstrate that excellent late results from repair of partial atrioventricular canal are possible when the mitral valve is managed as a bileaflet structure.