Inclusion Criteria:  Provision of signed and dated, written Informed Consent prior to any study specific proce-dures Patient: males and females must be ≥ 70 years old Patients who will undergo a TAVI procedure  Exclusion Criteria:  - No obtained signed, dated and written Informed Consent. Known thyroid dysfunction (for example: Basedow, Hashimoto,...) Patients receiving any of the following: Lithium, Strumazol or a recent treatment of radio-Iode