Abstract 16032: Damage Analysis of Crimping Pericardial Leaflets in TAVI
Objectives: Transcatheter aortic valve replacement (TAVR) is an emerging technology that is gaining expanded indications for the treatment of severe aortic stenosis. An important difference that may affect longevity between surgically implanted bioprosthetic and transcatheter aortic valves is the process of crimping, which is used in preparation of transcatheter valves. Through the use of advanced microscopy we sought to quantify the damage to the pericardial leaflets caused by crimping.
Methods: Scanning Electron Microscopy (SEM) and Second Harmonic Generation (SHG) Microscopy were used to examine the structural changes in the surface and deep layers of glutaraldehyde-fixed bovine pericardial tissue before and after crimping. A control sample of intact or un-crimped tissue was first imaged. Samples were then crimped to 14F, 16F or 18F for 20 minutes. Each of the crimped samples was then imaged immediately following crimping then 20 minutes and 60 minutes after crimping.
Results: A “Damage Index” which was based on the structural changes observed on SEM and SHG was defined. Based on comparisons to the un-crimped sample, it was observed that crimping does induce measurable structural damage to the pericardial tissue leaflets that persists with time. As crimping is increased to conform the valve to lower profiles, the damage induced by crimping is seen on deeper tissue layers, and persists (Figure 1).
Conclusions: Induced damage to the tissue leaflets may have a significant impact on the longevity of TAVR when compared to surgically implanted valves. Additionally, structural changes may result in complications such as thrombosis, early calcification or endocarditis. This information provides a potential mechanism for early device failure, and should be taken into consideration when choosing the best option for patients.
- © 2013 by American Heart Association, Inc.