Clinical Electrophysiology -> Atrial Fibrillation & Atrial Flutter: -> Left Atrial Appendage Closure D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-036 - Histologic Failure To Endothelialize Watchman And Watchman FLX LAAO Devices At Autopsy (ID 55)

Abstract

Background: LAA occlusion (LAAO) with Watchman or Watchman FLX is associated with device related thrombi (DRT) and subsequent embolic events. Post implant drug regimen assumes adequate endothelium formation beyond 3-6 months, allowing transition to aspirin as monotherapy. Little is known about the course or degree of human endothelium formation on LAAO devices at autopsy.
Objective: Evaluate gross and histologic appearance of the endoluminal surface on Watchman or Watchman FLX 6-24 months post-implant for the presence of endothelium.
Methods: Three patients followed at Vanderbilt Medical Center underwent analysis. Watchman case 1 died suddenly 9 months post LAAO (72yr M, CHADS2Vasc score 5), Watchman case 2 underwent CABG with excision of the LAA and the device implanted 2 years prior (86yr M, CHADS2Vasc 4). A Watchman FLX patient died from a DRT related embolic stroke with hemorrhagic conversion 6 months post implant (68yr M, CHADS2Vasc 4).
Results: All patients had complete seal of the LAA with no peri-device leak by TEE or CTA at 6-12 weeks post implant. This was confirmed at autopsy. Specimens were evaluated by gross inspection, H and E stain, Exakt sectioning and scanning electron micrography (SEM). No case had complete endothelial layering, and in all three, histology confirmed 20-35% of luminal surface area was completely bare PTFE fabric. Example Figure 1 (Case 1): Panel A-gross inspection; B-Exakt section with H and E, C-SEM region showing endothelium, D-SEM with bare PTFE.
Conclusion: Incomplete luminal endothelium on Watchman or Watchman FLX devices may account for late embolic events and sudden death from DRT. This appears independent of complete LAA occlusion by the device.
Collapse