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Mechanical valve replacement in congenital heart disease in children.

BACKGROUND AND AIM OF THE STUDY
The study aim was to analyze predictive factors of long-term results after mechanical heart valve replacement in children.


METHODS
Forty-four patients (19 males, 25 females; mean age 8.9+/-3.9 years, median 7.0 years, range: 1.3 to 15 years) underwent heart valve replacement with mechanical prostheses. Of these patients, 25 had left atrioventricular valve replacement (LavVR) (18 mitral, six tricuspid in corrected transposition of the great arteries (TGA), one common in a univentricular heart), 13 had aortic valve replacement (AVR) and six had tricuspid valve replacement (TVR). The etiology of the valvular disease was congenital in all patients, and complicated by infective endocarditis in seven (16%). Fifteen patients had undergone previous procedures and 16 required simultaneous repair of associated lesions. The mean size of the implanted prosthesis was 26 mm (range: 19-29 mm) for LavVR, 29.7 mm (range: 23-33 mm) for TVR, and 21.9 mm (range: 19-25 mm) for AVR. Postoperatively, all patients received oral anticoagulation. The mean follow up was 6.8+/-3.5 years (total 290 patient-years).


RESULTS
There was no early mortality, but three patients (7%) died later; all late deaths occurred in patients with LavVR. There were two sudden deaths, both in patients with complex congenital heart disease and heart failure (before the ACE inhibitor era), and one valve-related death from thrombotic occlusion of a mitral prosthesis. Five patients were reoperated on; three for patient-prosthesis mismatch, one for periprosthetic leak, and one for aortic dissection due to Marfan's syndrome. Thrombotic obstruction occurred in three patients; two in the tricuspid position were treated successfully with thrombolysis, but one in the left atrioventricular position proved fatal. After seven years, the survival rate was 93.4%.


CONCLUSIONS
Mechanical heart valve replacement in children aged over one year with congenital heart disease can be performed with satisfactory early and late results. Mechanical valves of >23 mm diameter in the atrioventricular position in the systemic ventricle, and >21 mm in the aortic orifice, can offer excellent long-lasting hemodynamic performance. However, mechanical valves in the tricuspid position are prone to develop thrombotic occlusion.