Redo TAVR: The impact of implanting balloon-expandable valves in failed self-expanding valves
Redo transcatheter aortic valve replacement (TAVR) that involves implanting a balloon-expandable valve into a degenerated and calcified self-expanding valve appears to be an effective treatment option, according to a new ex vivo bench study published in EuroIntervention.[1] However, certain size combinations worked better than others—and some resulted in below-average valve performance.
“Redo TAVR has emerged as a viable therapeutic option for patients with a failed transcatheter aortic valve (TAV),” wrote first author David Meier, MD, an interventional cardiologist with Lausanne University Hospital in Switzerland, and colleagues. “Redo TAVR serves as a minimally invasive alternative to surgical TAV explant, which has been shown to be associated with high morbidity and mortality due to patient risk factors and technical challenges, such as valve adherence, tissue ingrowth, and damage to surrounding structures. However, redo TAVR has many complexities and potential pitfalls. This procedure may not be feasible in all patients due to the risk of coronary obstruction and impaired coronary access, which requires careful consideration in procedural planning with respect to device combinations.”
Meier et al. performed ex vivo hydrodynamic testing on four Sapien 3 balloon-expandable TAVR valves from Edwards Lifesciences implanted into failed self-expanding CoreValve/Evolut TAVR valves from Medtronic. The failed devices were a 23-mm Evolut R, 29-mm CoreValve, 29-mm Evolut Pro and 34-mm Evolut R. All devices were surgically explanted from a TAVR patient due to structural valve degeneration that resulted in aortic stenosis or mixed stenosis and concomitant regurgitation.
Redo TAVR procedures were all performed on the bench with brand new Sapien 3 valves. A 20-mm Sapien 3 was implanted within the 23-mm Evolut R, a 26-mm Sapien 3 was implanted within the 29-mm CoreValve, a 26-mm Sapien 3 was implanted within the 29-mm Evolut Pro and a 29-mm Sapien 3 was implanted within the 34-mm Evolut R. In all instances, the Sapien 3 devices were implanted with their outflow at node 5 of the self-expanding valve. Depth was chosen based on prior experiences with bench testing redo TAVR procedures as well as CT-based simulation studies that tested multiple options. Hydrodynamic bench testing was performed using a HDTi-6000 heart valve pulse duplicator system from BDC Laboratories.
Overall, three of the four valve combinations were associated with “adequate” valve performance based on hydrodynamic testing. The one combination that did not deliver a positive performance was the 29-mm Sapien 3 with the 34-mm Evolut R, which resulted in a regurgitant fraction significantly higher than the predetermined 20% cutoff point. This may have been due to Sapien 3 underexpansion, the authors explained.
Median mean gradient, effective orifice area and peak velocity were 9.9 mm Hg, 2.1 cm2 and 1.9 m/s, respectively. Neoskirt heights ranged from 19.9 mm to 24 mm. Leaflet overhang ranged from 24.8% to 37.3%. Geometric orifice area (GOA) for the self-expanding valves ranged from 3.2 cm2 to 5.2 cm2. GOA for the balloon-expandable valves, meanwhile, ranged from 2.8 cm2 to 4.2 cm2.
Sapien 3 pinwheeling was observed in all four combinations, ranging from 12.5% to 29.8%. It was the highest when the 26-mm Sapien 3 was implanted within the 29-mm Evolut Pro.
The group also emphasized that coronary access did not appear to be negatively impacted by these redo TAVR simulations. This suggests patients undergoing these procedures will be able to be treated with percutaneous coronary intervention, for instance, if necessary following aortic valve replacement.
Meier and colleagues also noted that the wide range of data they observed highlight just how crucial it is to be careful when selecting device types and sizes, both during redo TAVR and the initial procedures. This grows even more crucial when treating a younger patient expected to outlive their TAV.
“These findings bring important focus on the importance of optimizing TAV type and size selection at the time of the index TAVR procedure in order to maximize the chances of successful redo TAVR,” they wrote. “Indeed, when considering the lifetime management of young patients, it is critical to consider the potential need for a subsequent intervention at the time of the index TAVR procedure.”
One key limitation of this research is that the procedures were not performed on patients. Many more studies are still required to help care teams learn more about how different TAVR valve types and sizes interact with one another during redo TAVR.
Medtronic did help fund this study. Some researchers had prior working relationships with both Medtronic and Edwards Lifesciences. Read the full study here.
Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.