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Feasibility of transcatheter techniques for intracardiac and extracardiac cavocaval connection in principle for Fontan completion in chronic animal models.

OBJECTIVES
We report the safety and feasibility of various transcatheter techniques of cavocaval connection in principle for the completion of Fontan circulation in viable, chronic and ovine heart models. Surgically simulated preparations of both intracardiac and extracardiac cavocaval connections were studied.


METHODS
Sixteen sheep were divided into two groups per the type of surgical preparation. All animals underwent standard right thoracotomy with interposition of a 20-mm Gore-tex(®) conduit between the superior vena cava (SVC) and the right atrium (RA). Nitinol rings were placed around the SVC and the inferior vena cava (IVC). In Group I (intracardiac, n = 10), the SVC-RA junction was closed using a polytetrafluoroethylene (PTFE) membrane 1 cm below the SVC-Gore-tex(®) anastomosis. In Group II (extracardiac, n = 6), a 20-mm Gore-tex conduit de-aired and filled with heparinized saline was anastomosed to connect the SVC and the IVC. The IVC end was anastomosed in a termino-lateral fashion and the SVC end in a termino-terminal fashion; both the ends were occluded with a PTFE membrane. Animals were scheduled for transcatheter cavocaval connection after a variable healing period.


RESULTS
Four animals in Group I died; three early and one late after surgical preparation. After a median interim period of 1 month (0-9 months), five sheep from Group I and six from Group II underwent successful transcatheter cavocaval connection. Perforation of the PTFE membrane was successful in all animals. Covered stents were deployed precisely and with good stability ensured by the nitinol rings. All animals survived transcatheter completion and were sacrificed after a median follow-up of 4 months (0-8 months) per protocol. No stent migration, thromboembolic events, residual shunts or paraprosthetic leak was noticed on angiographic evaluation or at autopsy in any animal.


CONCLUSIONS
Transcatheter techniques for completion of cavocaval connection in surgically simulated, chronic animal models is safe and feasible. Both techniques were equally successful with no failures or short-term complications. Such techniques should work in principle for completion of intracardiac and extracardiac Fontan circulation.