Replacement of the systemic atrioventricular valve with a mechanical prosthesis in children aged less than 6 years:: Late clinical results of survival and subsequent replacement

Objective: We analyzed the survival, clinical course, and role of prosthesis - patient mismatch after systemic atrioventricular valve replacement in children. Methods: From 1974 to 2006, 69 patients underwent systemic atrioventricular valve replacement (median age 1.2 years, range 1.1 months to 5.4 years), with 17 patients requiring re-replacement of the systemic atrioventricular valve. Prosthesis - patient relationship was analyzed by comparing (1) the prosthetic valve diameter and the predicted annulus diameter based on the body surface area and (2) the prosthetic valve diameter and the measured annulus diameter. Results: Survival was 73% at 1 year and 65% at 5, 10, and 15 years. Age, weight, body surface area, predicted annulus diameter, prior surgery, underlying disease, and ratio of prosthetic valve diameter to body weight were significant predictors of death. Variables associated with re- replacement of the systemic atrioventricular valve were body surface area, prosthetic valve diameter, predicted annulus diameter, and presence of multiple left- sided obstructive lesions. The majority of patients received a prosthesis larger than the predicted annulus diameter. There was good correlation between the prosthetic valve diameter and the measured annulus diameter (r = 0.85). Mismatch, as described by the difference in z scores of prosthetic valve diameter and measured annulus diameter, was not a significant predictor of death or re-replacement of the systemic atrioventricular valve. Conclusions: Although valve replacement is considered the last therapeutic option after failed attempts of valvuloplasty, long-term outcome is favorable. Selection of the prosthesis is made on the basis of the measured annulus diameter. An elevated ratio of prosthetic valve diameter to body weight is associated with patients with low body weight or a large native annulus in dilated ventricles.