Background and aim of the study: Although severe tricuspid regurgitation (TR) is a well-recognized, long-term complication of rheumatic mitral valve replacement that impairs the functional results of surgery, its exact basis remains unclear and its management is unsatisfactory. The study aim was to obtain a detailed assessment of tricuspid valve morphology and function using 2D transesophageal echocardiography (TEE) with 3D reconstruction, and to determine long-term clinical outcome in patients after surgery for rheumatic mitral valve disease.
Methods: A total of 42 patients (mean age 50 +/- 10 years) was followed up; 39 patients had mitral replacement and three had valvotomy. Thirty patients had developed impaired exercise tolerance, fluid retention and echocardiographic evidence of severe TR at 8.2 +/- 2.6 years after surgery; the remainder had mild regurgitation.
Results: Follow up showed greater mortality in the severe TR group, with approximately 50% survival at 60 months after diagnosis compared with mild TR. None of the patients with severe TR had a dysfunctional mitral prosthesis. In these patients, transthoracic echo-Doppler showed enlarged right atrium and right ventricle, a mean transtricuspid retrograde pressure drop of 15 +/- 4 mmHg and apparently normal leaflet anatomy. Twenty patients (15 with severe TR) underwent a TEE and 3D reconstruction study for further evaluation. Abnormal leaflet anatomy was demonstrated in all patients with severe TR, with restricted leaflet motion in 10, leaflet shortening and thickening in the remainder, and dilatation of tricuspid valve annular insertion suggestive of rheumatic involvement. Although diastolic transtricuspid velocities were increased (peak flow 0.8 +/- 0.1 m/s) in these patients due to increased stroke volume, significant tricuspid stenosis was present in only two cases (mean gradient 4 and 3 mmHg respectively). Histopathology confirmed the presence of leaflet vascularization and extensive fibrosis in two patients who underwent tricuspid valve replacement.
Conclusion: Rheumatic leaflet involvement contributes to severe TR occurring long after mitral valve replacement, though overt stenosis is uncommon. Knowledge of the structural basis of this condition may thus improve its long-term management, possibly with early tricuspid valve repair.