Transcatheter treatment of tricuspid regurgitation by caval valve implantation--experimental evaluation of decellularized tissue valves in central venous position.

BACKGROUND: Caval valve implantation has been suggested for transcatheter treatment of severe tricuspid regurgitation (TR). Combining the interventional technique with the promising surgical experience with decellularized valves, we sought to evaluate the functional and structural outcome of decellularized pericardial tissue valves (dTVs) in the low-pressure venous circulation in a chronic model of TR. METHODS AND RESULTS: Sixteen pericardial tissue valves were heterotopically implanted in the inferior and superior vena cava in a sheep model (54-98 kg; median 74.5 kg, n = 8) of severe TR. The devices were assembled using self-expanding nitinol stents and bovine pericardia decellularized by a detergent-based protocol (group dTV; n = 8). Glutaraldehyde-fixed pericardial tissue valves served as control (GaTV, n = 8). After 6 months, device function and structural maturation were analyzed using echocardiographic, histologic, immunohistologic, and electron microscopic approaches. After implantation, cardiac output increased significantly from 3.7 ± 1.1 l/min to 4.8 ± 1.1 l/min (P < 0.05) and competent valve function was verified by angiography. At 6 months, angiographic and echocardiographic evaluation revealed moderate to severe regurgitation in all GaTV. In contrast, five of the eight dTVs functioned well with only minor regurgitation. In these animals, autopsy revealed preserved valve structure with tender leaflets without signs of thrombosis or calcification. Conversely, GaTV showed severe degeneration with large calcification areas. Microscopic and histologic analysis confirmed endothelial repopulation in both valve types. However, additional interstitial reseeding was observed in decellularized valves. CONCLUSIONS: In the venous circulation in severe TR, decellularized valves show superior functional performance compared to Ga-fixed tissue valves. Macroscopic and microscopic analyses suggest preserved structural integrity and advanced endothelial and interstitial repopulation with evidence of less degradation in dTV. © 2014 Wiley Periodicals, Inc.

Percutaneous caval stent valve implantation: investigation of an interventional approach for treatment of tricuspid regurgitation.

AIMS: Severe tricuspid regurgitation (TR) reduces cardiac output (CO) and increases central venous pressure leading to secondary organ dysfunction. To date, the open surgical approach is the only option to treat TR. Herein, we report our experience of treatment by percutaneous implantation of valved stents in the inferior vena cava (IVC) and superior vena cava (SVC) to substitute tricuspid valve function in a model of acute insufficiency. METHODS AND RESULTS: Acute TR grades III-IV was created in 13 sheep (54-75 kg) via papillary muscle and chordae avulsion using a 0.07 inch wire blade. Successful creation of TR was confirmed using angiography and by a prominent ventricular wave in central venous pressure recording. Two self-expanding nitinol stents containing a porcine pulmonary valve were then implanted in the IVC and SVC in a transcatheter approach. Implantation was performed through the right jugular vein by means of a 21 F catheter and guided by fluoroscopy. Haemodynamics were continuously monitored and valve function was verified by angiography and epicardial echocardiography. After successful implantation and proof of concept in the acute study (acute group, n = 9), chronic studies were (n = 4, 4 weeks follow-up) performed. Tricuspid regurgitation grades III-IV was successfully created in all animals and resulted in a significant reduction of CO. A ventricular wave in the IVC of 16.2 +/- 2.33 mmHg (acute group) and 14.9 +/- 1.71 mmHg (chronic group) confirmed the presence of severe TR. After deployment of the IVC and the SVC valve, the ventricular wave in the IVC significantly decreased to 13.9 +/- 2.97 mmHg (acute group) and 12.7 +/- 1.15 (chronic group), whereas CO significantly increased to 4.20 +/- 0.84 L/min (acute group) and 5.4 +/- 0.67 L/min (chronic group). At autopsy, correct device position was verified in all successfully implanted animals, no macroscopic damage resulting from the implantation procedure was observed. CONCLUSION: In high-grade tricuspid insufficiency, percutaneous implantation of valved stents in the central venous position reduces venous regurgitation and improves haemodynamics in the animal experiment. Implantation of one or two valves in central venous position is technically feasible. Functional replacement of the insufficient tricuspid valve leads to an increase in CO. This technique expands the potential therapeutic options for patients with relevant tricuspid valve regurgitation having a high risk for open heart surgery.