The Bicuspid Valve: Does TAVR Compete with SAVR? Are We Ready for a Randomized Trial, and in Whom?

2.3  /  IAGS 2019
Session 1: Structural Session 1: Aortic
The Bicuspid Valve: Does TAVR Compete with SAVR? Are We Ready for a Randomized Trial, and in Whom?
Problem Presenter:  David A. Wood, MD

 

Statement of problem or issue

Transcatheter aortic valve replacement (TAVR) is an alternative therapy to surgery for patients with calcific aortic stenosis irrespective of surgical risk. However, patients with bicuspid valve anatomy have been excluded from the landmark randomized controlled trials. Procedural concerns that may impact transcatheter heart valve (THV) deployment in bicuspid patients include elliptical annuli, asymmetric and bulky calcium distribution, and lower coronary artery heights. All the above may adversely impact both THV positioning and expansion as well as increase the incidence of paravalvular leak and procedural complications. Despite a lack of evidence from randomized controlled trials, successful implants have been performed in a number of bicuspid aortic valve patients with favorable short-term results. However, the long-term durability remains unknown.

Gaps in knowledge

Current gaps in knowledge include optimal sizing, THV selection, the effect of concomitant aortopathy, and mechanical durability. There is currently considerable variability in THV sizing for bicuspid patients. Some sites use a “supra-annular” approach for sizing; however, there is no standardized or reproducible approach to bicuspid valve sizing. The optimal THV platform for bicuspid patients is also poorly understood. In addition, the implications of a concomitant aortopathy is poorly understood. In some patients with an associated aortopathy and aortic valve stenosis, surgery may be a better option. Finally, it is unclear if the long-term durability of TAVR in bicuspid valve patients will be similar to patients with degenerative trileaflet calcific aortic valve stenosis.

Possible solutions and future directions

As TAVR expands to lower-risk and younger patients, where there is a greater likelihood of bicuspid anatomy, the results of an adequately powered randomized trial will be crucial to help address the existing knowledge gaps. In younger patients, an understanding of factors that may impact durability will help guide THV selection. While THV platforms designed specifically to accommodate the unique challenges of bicuspid valve anatomy are still on the horizon, novel techniques have recently been developed that involve laceration of the bicuspid valve leaflets to facilitate procedural success and mitigate the risk of coronary obstruction. While promising, these techniques are still in their infancy.