Small intestinal submucosa tricuspid valve tube graft shows growth potential, remodelling and physiological valve function in a porcine model†.

OBJECTIVES: Tricuspid valve reconstruction using small intestinal submucosal extracellular matrix (ECM) designed as a tube graft is possible in severe valve pathology. Using cardiac magnetic resonance imaging (MRI) and digital photograph imaging, valves were evaluated after 6 months in a porcine model.

METHODS: Ten 60 kg pigs received a tricuspid valve tube graft. A baseline MRI was performed after 2 weeks ( n  = 8). A follow-up MRI was performed in three of five 6 months' survivors to assess function and haemodynamics of the tricuspid tube graft. Valves were explanted in five animals for gross examination. No statistical comparisons were made due to low numbers.

RESULTS: : Compared to the original tube graft, leaflet area and leaflet height decreased after 6 months (32  ±  0 vs 14.7  ±   4 cm 2 and 3.2  ±   0 vs 1.7  ±   0.3 cm, respectively). Both imaging modalities showed septal dehiscence in all tube grafts after 6 months causing haemodynamically severe paravalvular regurgitation. Cardiac MRI showed a significant remodelling of the right ventricular and annular dimensions. The cardiac output decreased (67  ±  16 vs 34  ±  5 ml/min/kg), while right ventricular stroke volume increased from 64.4  ±  14.6 to 107  ±  63.9 ml. This corresponded to a paravalvular regurgitant volume increasing from 7.2  ±  7.3 to 71.7  ±  69.6 ml.

CONCLUSIONS: The ECM tube grafts seemed to remodel over time with loss of redundant ECM material. However, tube graft dehiscence caused severe tricuspid paravalvular regurgitation and heart failure. These data suggest that surgical reinforcement, e.g. adjunct annuloplasty, should be considered to improve durability.