A novel detachable filter to prevent thromboembolism during endovascular surgery

Objective

Thromboembolism remains a serious complication during endovascular surgery. Commercially available filter devices, which are unified with the stenting systems, provide short-time performance owing to the adhesion of thrombus to the filters themselves. We have, therefore, developed a new detachable filter that can be used in all major aortic branches and shows greater longevity. The present study assessed the efficacy of the new detachable filter and examined the feasibility of deploying and retrieving the filters.

Methods

We first performed in vitro studies. Our experimental flow model used silicon tubing to simulate the aortic branches. Polystyrene-divinylbenzene microspheres (100 and 200 μm in diameter), which simulated embolic particles, were injected into the tubing after the detachable filter was deployed. The capture efficacy (number of microspheres trapped in the detachable filter/total injected microspheres) was calculated. In the in vivo studies, the detachable filters were implanted into the carotid, visceral, and renal arteries of 5 mongrel dogs. Angiography was performed every 30 minutes. At 5 hours after implantation, each detachable filter was retrieved by a gooseneck snare catheter.

Results

In the in vitro studies, our detachable filters showed high capture efficacy, capturing 99.2% of the 100-μm microspheres and 99.4% of the 200-μm microspheres. In the in vivo studies, all detachable filters were successfully deployed into the major branches. Each angiographic study revealed smooth flow without any embolic obstruction of the filter. At 5 hours after deployment, all devices were completely retrieved by the snare catheter without aortic injury.

Conclusions

The new detachable filter showed high efficacy in capturing the particles. All detachable filters were successfully deployed for 5 hours, and the filters were retrieved from the aortic branches without any complications. This novel detachable filter can help prevent serious distal thromboembolism during endovascular surgery.