Background: Major uncertainties remain regarding disease activity within the retained native aortic valve, and regarding bioprosthetic valve durability, after transcatheter aortic valve implantation (TAVI). We aimed to assess native aortic valve disease activity and bioprosthetic valve durability in patients with TAVI in comparison with subjects with bioprosthetic surgical aortic valve replacement (SAVR). Methods: In a multicenter cross-sectional observational cohort study, patients with TAVI or bioprosthetic SAVR underwent baseline echocardiography, computed tomography angiography, and ¹⁸ F-sodium fluoride ( ¹⁸ F-NaF) positron emission tomography. Participants (n=47) were imaged once with ¹⁸ F-NaF positron emission tomography/computed tomography either at 1 month (n=9, 19%), 2 years (n=22, 47%), or 5 years (16, 34%) after valve implantation. Patients subsequently underwent serial echocardiography to assess for changes in valve hemodynamic performance (change in peak aortic velocity) and evidence of structural valve dysfunction. Comparisons were made with matched patients with bioprosthetic SAVR (n=51) who had undergone the same imaging protocol. Results: In patients with TAVI, native aortic valves demonstrated ¹⁸ F-NaF uptake around the outside of the bioprostheses that showed a modest correlation with the time from TAVI ( r =0.36, P =0.023). ¹⁸ F-NaF uptake in the bioprosthetic leaflets was comparable between the SAVR and TAVI groups (target-to-background ratio, 1.3 [1.2–1.7] versus 1.3 [1.2–1.5], respectively; P =0.27). The frequencies of imaging evidence of bioprosthetic valve degeneration at baseline were similar on echocardiography (6% versus 8%, respectively; P =0.78), computed tomography (15% versus 14%, respectively; P =0.87), and positron emission tomography (15% versus 29%, respectively; P =0.09). Baseline ¹⁸ F-NaF uptake was associated with a subsequent change in peak aortic velocity for both TAVI ( r =0.7, P <0.001) and SAVR ( r =0.7, P <0.001). On multivariable analysis, ¹⁸ F-NaF uptake was the only predictor of peak velocity progression ( P <0.001). Conclusions: In patients with TAVI, native aortic valves demonstrate evidence of ongoing active disease. Across imaging modalities, TAVI degeneration is of similar magnitude to bioprosthetic SAVR, suggesting comparable midterm durability. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02304276.

In the current era of transcatheter device therapy, the prevalence of prosthetic aortic valves and their associated complications is increasing. Echocardiography remains the first-line imaging investigation for the assessment of prosthetic valve complications, however, this often fails to identify the underlying mechanism of prosthesis failure. Recently, cardiac CT has emerged as an imaging technique capable of providing high isotropic spatial resolution of the prosthetic valve and its utility can provide important complementary diagnostic information. In this pictorial review, we present a series of common prosthetic aortic valve complications imaged with cardiac CT and demonstrate how use of this modality can enhance diagnostic accuracy.