MONOCUSP VALVE AND TRANSANNULAR PATCH RECONSTRUCTION OF THE RIGHT-VENTRICULAR OUTFLOW TRACT - AN EXPERIMENTAL-STUDY

Repair of congenital right ventricular outflow tract obstruction often requires reconstruction with a transannular patch to alleviate pulmon ary stenosis. Post repair pulmonary insufficiency with right ventricul ar dilatation and volume overload may result and lead to acute or prog ressive right heart failure. The use of a monocusp valve has been prop osed as a means to prevent this problem. Fresh pericardium is well kno wn to fail clinically, leading to pulmonary insufficiency limiting mid - and long-term results. In a chronic dog model (147 +/- 34 days), thr ee valve types were evaluated: 1) polytetrafluoroethylene (PTFE; n = 9 ), 2) fresh pericardium (PERI; n = 6), and glutaraldehyde fixed perica rdium (GLU; n = 6). Hemodynamics, angiography, and echocardiography we re performed at implantation and sacrifice. Cross and microscopic path ology were evaluated. No significant differences were found among the three groups with regard to stenosis as evaluated by echocardiography, measured right ventricular wall thickness, and hemodynamic pressure g radients across the valve. By echocardiography, both PTFE (1 of 9) and GLU (0 of 6) showed less regurgitation than PERI (5 of 6) (p < 0.05). This was confirmed by angiography. PTFE showed less neo-intimal hyper plasia, less thrombus formation, and less calcification than GLU or PE RI (p = NS). The PTFE monocusp developed no prohibitive gradients, no early pathologic deterioration, and maintained competence compared wit h the GLU and PERI groups. Although continued investigation of long-te rm durability and competence of the PTFE monocusp valve is warranted, both PTFE and GLU values seem to demonstrate less regurgitation than t he PERI monocusp valve in an adult dog model of right ventricular outf low tract reconstruction.