Establishment Of Patent Foramen Ovale Model And Experimental Study Of Paradoxical Embolism

Objective: To investigate the feasibility of developing a patent foramen ovale (PFO) model in piglets by percutaneous technique, and to evaluate the association between the Valsalva maneuvers and the paradoxical embolism in animals with this model. Methods: Percutaneous atrial trans-septal puncture and balloon dilation was conducted in eleven healthy piglets (one as pre-experimental animal, ten as experimental animals). The experimental piglets then received an intravenous injection of emboli. During the injection, five piglets (group 1) experinced the Valsalva-provoking activity, and five other ones (group 2) did not. Results: Artificial PFO was successfully created in all 11 piglets. Though no reversal of inter-atrium mean pressure gradient was found in 5 piglets of group1, a reversal of inter-atrium instantaneous pressure gradient (RIIP) occurred in 4 of the 5 piglets, and two of them suffered from the paradoxical embolism, verified by MRI and pathological examinations. Neither reversal of RIIP nor the paradoxical embolism was observed in any one of group 2. Conclusion: Artificial creation of PFO in piglets is feasible by percutaneous techeique. The Valsalva maneuver which leads to a reversal of inter-atrium instantaneous pressure gradient is associated with the paradoxical embolism in animals with PFO.