[The effect of oversized occluder on endothelialization after percutaneous closure of experimental atrial septal defect in dogs].

OBJECTIVE

To observe the effect of oversized occluder on endothelialization post percutaneous closure of experimental atrial septal defect (ASD) in dogs.

METHODS

ASD was established with the help of transthoracic echocardiography in 18 dogs. ASD size was (6.0 ± 0.2) mm. Dogs were randomly divided into normal size group (implanted with 8 mm occlude, n = 9) and oversized group (implanted with 12 mm occluder, n = 9). Dogs were randomly killed at 3, 6 and 14 months after percutaneous closure. The endothelialization process on device surface was observed by scanning electron microscope.

RESULTS

Four animals died around 1 month post procedure. Microscopic sections from normal group showed nearly complete endothelialization at 3 months after device implantation and complete endothelialization at 6 and 14 months after device implantation. While microscopic sections showed lack of endothelialization at 3 months post implantation, nearly endothelialization at 6 months, and complete endothelialization at 14 months after device implantation in oversized group.

CONCLUSION

Incomplete endothelialization of occluder surface is observed at 6 months after implantation of an oversized ASD occluder device in this model.