Cone reconstruction for severe tricuspid valve dysplasia in a dog.

Tricuspid valve dysplasia (TVD) is a congenital cardiac malformation in dogs characterized by abnormal tricuspid valve morphology, leaflet tethering, impaired leaflet coaptation, and right atrial and ventricular remodelling. This report describes cone reconstruction for severe TVD in a dog. A three-year-and-10-month-old female Labrador retriever presented with a grade IV/VI systolic murmur and exercise intolerance. Echocardiography revealed severe tricuspid regurgitation, a right atrial-to-left atrial ratio of 1.57, malformed and tethered tricuspid valve leaflets, impaired leaflet coaptation, and marked right-sided cardiac enlargement, consistent with severe TVD. Surgery involved tricuspid valve leaflet mobilization, delamination of adherent leaflet tissue and abnormal subvalvular attachments, annular reduction, and reconstruction of the available leaflet tissue into a cone-like valve with leaflet rotation and reattachment. A small, thin, dysplastic portion of the right ventricular free wall was also excluded from the functional right ventricular cavity by longitudinal plication. The dog was discharged on postoperative day seven without other major complications. On postoperative day 294, echocardiography showed a reduction in the colour Doppler tricuspid regurgitant jet, a decrease in the right atrial-to-left atrial ratio to 0.50, and a reduction in right atrial size. Exercise intolerance resolved, although a grade III/VI systolic murmur persisted. Cone reconstruction, adapted from the technique used in human patients with Ebstein's anomaly, may improve tricuspid valve function and clinical signs in selected dogs with severe TVD. However, its indications, reproducibility, and long-term durability in dogs remain unestablished. Further studies are needed to evaluate patient selection, long-term benefits, and potential complications.