Structural valve dysfunction (SVD) is the most common and life threatening complication in patients treated by aortic valve replacement. A calcification process is frequently involved in SVD but its pathophysiology remains unclear. In the hypothesis of an active metabolic phenomenon of calcification, as previously shown in native aortic valve stenosis, rather than a passive deposit of calcium in valve tissue, positon emission tomography (PET) imaging with 18F-Fluoride could emphasize increased osteoblastic activity in SVD tissue.

This study will include patients with echocardiography-confirmed SVD. Echocardiographic parameters and other current parameters analyzed in SVD patients such as bioprosthesis calcium scoring derived from CT will be compared to 18F-Fluoride activity.

Inclusion Criteria:

• age > 18
• written informed consent
• SVD defined on echocardiography by an alteration of bioprosthesis leaflets function with a mean transvalvular gradient > 20 mmHg and maximal velocity ≥ 3 m/s and effective orifice area ≤1.2 cm², and/or an aortic regurgitation more or equal to grade 2 on 4.

Exclusion Criteria:

• Inability to give informed consent
• Pregnancy
• Concurrent antibiotherapy
• Certain infectious endocarditis
• Concurrent anti-inflammatory therapy, including corticosteroid therapy