Pathologic Analysis of Transcatheter Aortic Valve Explants.
Elena R Ladich, Naima Carter-Monroe, Robert Kutys, Raoul Bonan, Renu Virmani. CVPath Institute Inc, Gaithersburg; Montreal Heart Institute, Canada
Background: Transcatheter aortic valve implantation (TAVI) is a therapeutic option for high-risk patients with aortic stenosis not considered to be suitable candidates for surgical aortic valve replacement. Two primary transcatheter technologies are currently utilized: the Edwards percutaneous heart valve (PHV) (Edwards Lifesciences, Irvine, CA) and the CoreValve aortic prosthesis (Medtronic, Minnapolis, MN). Gross and histopathologic examination provide insights into the pathologic changes that occur over time in explanted valves.
Design: 11 Edwards PHV valves and 5 CoreValve explants were examined. Gross observations included prosthetic valve location, stent expansion, apposition to the aortic root and integrity of the prosthetic valve leaflets. All sections were examined by light microscopy for the presence of neointima, inflammation, calcification, thrombus/vegetations and degeneration of pericardial leaflets. In addition, clinical records were reviewed when available.
Results: Implant durations for the Edwards PHV ranged from 1 day to 4 years (age 81-91 years). The stent frames were intact and anchored in the native annulus. Histologically, there was early platelet/fibrin deposition which eventually formed a thin layer of neointima around the devices. Leaflets showed mild inflammation and over time basal pannus formation. In one acute death, there was obstruction of the left main ostium by native calcified leaflet evulsing over the device. A Type I aortic dissection associated with extensive nodular calcification of the native leaflets was identified at 3 years. One valve showed infective endocarditis. The 5 CoreValves had postimplant times ranging from 3 days to 350 days (age range: 77-85 yrs). The self-expanding frames conformed to the aortic root with patent coronary ostia. The mitral leaflet was intact in all explants. Postmortem analysis showed early platelet/fibrin deposition and formation of thin pannus over time. One autopsy case (3 days) showed a perforation in the aortic root close to the left main ostium. Another device was placed too low with a valve in valve implanted as bail out. There was thick pannus formation around leaflet bases in one patient with cardiac amyloidosis (350 days).
Conclusions: There were no device fractures even as late as 4 years. Tissue growth around the devices, leaflet inflammation, basal leaflet pannus growth, and endocarditis were similar to those previously reported for surgically implanted valves. The degree of native leaflet calcification may play a role in early and late complications and deserves further study.
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 37, Wednesday Afternoon