PTFE Monocusp Valve for RVOT Reconstruction
Patient Selection
The surgical management of patients with tetralogy of Fallot and significant right ventricular outflow tract obstruction (RVOTO) remains controversial. For patients who have a congenitally small pulmonary valve annulus who are not candidates for a valve-sparing repair, there have historically been two options: (1) transannular patch or (2) valved conduit insertion. The advantage of the transannular patch is that it relieves the RV pressure immediately and the child usually will not require reoperation for RV outflow tract stenosis.
A disadvantage of this technique is the sudden hemodynamic change for the RV from a pressure-loaded to a volume-loaded ventricle, which, when combined with VSD closure on one side and ventriculotomy on the other, often causes temporary RV dysfunction. The chronic volume overload can lead to ventricular dysfunction from chronic pulmonary valve insufficiency, and require late pulmonary valve insertion Ä1Å.
The advantage of the valved conduit technique is that it results in a reliable, fully competent pulmonary valve. This is particularly useful in patients who have peripheral unrepaired pulmonary stenosis. The disadvantage is that all conduits (or pulmonary valves) are subject to progressive stenosis, either from patient growth or calcification of the valves, and conduit replacement is eventually needed.
An interesting alternative strategy is the creation of a monocusp RV outflow tract patch. A monocusp may be created with autologous or bovine pericardium Ä2Å, homograft pulmonary valve cusp, or as reported in this technique section, the use of PTFE pericardial membrane (0.1 mm PTFE patch) Ä3Å. The monocusp has been shown, particularly in the immediate postoperative period, to prevent pulmonary valve insufficiency Ä4Å. This may be associated with faster recovery of RV function, a lower central venous pressure, and less chest tube drainage.
The construction of the monocusp is simple, very inexpensive, and reproducible. The potential disadvantage in comparison to insertion of a pulmonary valve or valved conduit is that, at least in some patients, there appears to be a faster progression to recurrent pulmonary valve insufficiency, although late stenosis is rarely, if ever, seen using this technique.
The patient selected for this procedure would be one for whom the surgeon would consider either a transannular patch or a pulmonary valve insertion at the time of initial tetralogy of Fallot repair, or a patient having a reoperation after initial transannular patch or valved conduit placement.
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