ANTIPLATELET THERAPY IN CHILDREN WITH LEFT-SIDED MECHANICAL PROSTHESES

Valve replacement in children has always been associated with a high m ortality, outgrowth of the prosthetic valve and difficulty in managing anticoagulation. Between January 1985 and April 1991, 20 patients (14 males and 6 females) underwent replacement of a left-sided cardiac va lve. The median age at diagnosis was 21.6 months (1 to 120 months) and the median age at surgery was 85 months (11 to 213 months). Six patie nts were under 4 years of age. The site of valve replacement was aorti c in 11 patients and left atrioventricular (AV) valve in 9 patients. T he indications for aortic valve replacement were stenosis (6) and inco mpetence (5). The left AV valve was replaced in three patients followi ng repair of AV septal defect, in one patient with corrected transposi tion of the great arteries (L TGA), in one patient with severe dysplas ia and insufficiency, and in four patients for congenital mitral steno sis. A Bjork-Shiley prosthesis was used in three mitral and one aortic position, all the other patients receiving a St. Jude prosthesis: six mitral and ten aortic. All patients were anticoagulated (warfarin) fo r 3 months post implantation and then switched to a regimen of aspirin and persantine. There was no early or late death. Median follow-up wa s 12.3 months (4 to 72 months). Total follow-up was 59 patient-years o r 708 months. There was one incident of thromboembolism (1.7%/patient- year) and four instances of bleeding (6.8%/patient-year). There was no valve thrombosis. Our regime of early warfarin followed by long-term antiplatelet therapy has been associated with a low incidence of throm boembolism and no valve thrombosis.