**2. Indications of valve-in-valve TAVR**

#### **2.1 Outcomes of redo aortic valve replacement**

The use of bioprosthetic valve in AVR has been expanding. That will inevitably lead to increased number of patients who need re-aortic valve replacement for degenerated bioprostheses. Redo aortic valve replacement carries a higher operative risk compared to primary aortic valve replacement.

Kaneko et al. investigated 3,380 patients from The Society of Thoracic Surgeons database who underwent elective, isolated redo aortic valve replacement (AVR) after a previous AVR [3]. The operative mortality was 4.6%, and the incidence of



*The Current Perspectives in Valve-in-Valve Transcatheter Aortic Valve Replacement DOI: http://dx.doi.org/10.5772/intechopen.97521*

*TAVR: transcatheter aortic valve replacement; SAVR: surgical aortic valve replacement; PPM: prosthesis-patient mismatch.*

#### **Table 1.**

*Previous studies which reported the clinical outcomes of valve-in-valve TAVR.*

mortality, morbidity, stroke, postoperative aortic insufficiency mild or greater, pacemaker implantation and vascular complications was higher in redo AVR group compared to primary AVR patients.
