**2.2 Outcomes of valve-in-valve TAVR**

Overall the outcomes of valve-in-valve TAVR have been reported to equivalent or better compared to those of redo surgical AVR.

The Valve-in-Valve International Data (VIVID) reported the outcomes of valvein-valve TAVR for 459 patients in 55 centers [4]. The thirty-day mortality was 7.6%. Overall one-year survival rate was 83.2% Patients with bioprosthetic stenosis had worse 1-year survival compared with the patients with bioprosthetic regurgitation. Patients with small valves had worse 1-year survival compared to intermediate or large valves.

The Transcatheter Valve Therapy (TVT) Registry showed that unadjusted 30-day mortality after valve-in-valve TAVR was 2.9%, and it was better than that of native valve TAVR (4.8%) [5].

The PARTNER (Placement of Aortic Transcatheter Valves) 2 trial showed that 30-day mortality was 2.7%, stroke was 2.7%, major vascular complication was 4.1%, conversion to surgery was 0.6%, coronary occlusion was 0.8%, new pacemaker insertion was 1.9%, and one year all-cause mortality was 12.4% [6]. Recently 3-year outcomes after valve-in-valve TAVR in the Partner 2 registry was published [7]. The mean age of the patients was 78.9 ± 10.2 years. At 3 years, the estimate all-cause mortality was 32.7%. Quality of life of the patients improved compared to baseline.

Neupane et al. conducted a meta-analysis of the previously reported studies to determine outcomes after valve-in-valve TAVR and redo AVR [8]. Their analysis showed no difference in 30-day mortality between valve-in-valve TAVR and redo AVR for failed bioprosthetic aortic valve.

Previous studies which reported the clinical outcomes of valve-in-valve TAVR are listed in **Table 1**.
