Occlusion of canine atrial appendage using an expandable silicone band

Because the left atrial appendage is thought to be a major source of stroke in patients with atrial fibrillation, a new device and technique were developed for thoracoscopic isolation of the left atrial appendage.

The left and right atrial appendages were approached from an 11.5-mm port in the left thorax in 15 canines. With an atraumatic grasper for appendage positioning, expandable silicone bands covered with polyester fabric were placed at the base of the left and right atrial appendages. The location of the bands was marked with radiopaque clips to assess migration, and radiopaque dye was injected to confirm occlusion. The animals were killed at 1 week (n = 3), 2 weeks (n = 6), or 12 weeks (n = 6).

The bands were deployed on 30 appendages without complications. The appendages were 100% occluded, and there was no migration of any bands at death. There was no indication of bleeding, rupture, or systemic emboli in any of the 15 animals. Following complete occlusion, the appendages became necrotic and were replaced by scar tissue. The healed atrial surface was consistently smooth and devoid of thrombus. There was evidence of mild-to-moderate inflammation associated with a foreign body-type reaction to the fabric material but no pericarditis.

Permanent occlusion of the left atrial appendage is feasible via a thoracoscopic epicardial approach with this novel silicone band. As the atrial tissue becomes necrotic, the silicone band continues to constrict, ensuring that the appendage remains isolated. Band occlusion of the left atrial appendage could potentially improve overall treatment outcome in patients at high risk of atrial thrombus formation.