SURGICAL TREATMENT OF STRADDLING TRICUSPID VALVES

Six patients whose cardiac malformations included a large ventricular septal defect (VSD) in the inlet portion of the septum and straddling tricuspid valve underwent corrective intracardiac operations. In four patients, both the tricuspid valve annulus and its tensor apparatus occupied part of each ventricle. In one, only the annulus overrode the ventricular septum and in one the annulus was normally positioned, but a portion of the tensor apparatus crossed through the VSD from its origin in the left ventricle. This last patient had related mitral valve incompetence. One patient had an isolated VSD and one had isolated, multiple VSDs and a previously banded pulmonary artery. Associated malformations in the other four included tetralogy of Fallot, double outlet right ventricle, transposition of the great arteries with severe tricuspid incompetence, and corrected transposition. Hypoplasia of the sinus portion of the right ventricle was present to some degree in four patients. Preoperatively the diagnosis was definitively established by axial cineangiocardiograms in three and suspected in one. The straddling tricuspid valve was preserved in the repair in five patients, but tricuspid valve replacement was used in the patient with severe tricuspid incompetence. In one case, intraoperative electrophysiologic mapping studies were performed and showed abnormal conduction pathways. Five patients survived the hospital period. Postoperative cardiac catheterization studies were performed in four, one of whom died 16 months postoperatively from chronic congestive heart failure. The remaining four survivors have had a good clinical result.