Transcatheter Aortic Valve Replacement for Failed Surgical or Transcatheter Bioprosthetic Valves: A Comprehensive Review.

Transcatheter aortic valve replacement (TAVR) has proven to be a safe, effective, and less invasive approach to aortic valve replacement in patients with aortic stenosis. In patients who underwent prior aortic valve replacement, transcatheter and surgical bioprosthetic valve dysfunction may occur as a result of structural deterioration or nonstructural causes such as prosthesis-patient mismatch (PPM) and paravalvular regurgitation. Valve-in-Valve (ViV) TAVR is a procedure that is being increasingly utilized for the replacement of failed transcatheter or surgical bioprosthetic aortic valves. Data regarding long-term outcomes are limited due to the recency of the procedure's approval, but available data regarding the short- and long-term outcomes of ViV TAVR are promising. Studies have shown a reduction in perioperative and 30-day mortality with ViV TAVR procedures compared to redo surgical repair of failed bioprosthetic aortic valves, but 1-year and 5-year mortality rates are more controversial and lack sufficient data. Despite the reduction in 30-day mortality, PPM and rates of coronary obstruction are higher in ViV TAVR as compared to both redo surgical valve repair and native TAVR procedures. New transcatheter heart valve designs and new procedural techniques have been developed to reduce the risk of PPM and coronary obstruction. Newer generation valves, new procedural techniques, and increased operator experience with ViV TAVR may improve patient outcomes; however, further studies are needed to better understand the safety, efficacy, and durability of ViV TAVR.