Chronic kidney disease (CKD) and (subsequent) acute kidney injury are frequent in patients undergoing transcatheter aortic valve implantation (TAVI). Moreover, these patients are easily hypervolemic and susceptible for cardiac decompensation. Prevention of contrast induced nephropathy (CIN) has not yet been studied in these patients, and evidence on different strategies is urgently needed. The objective of this study is to evaluate the efficacy of 250ml 1.4% sodium bicarbonate versus hypotone saline (0.65% sodiumchloride) hydration prior to TAVI in patients with CKD to prevent CIN.

Inclusion Criteria:

1. Patient has provided written informed consent.
2. Patient is undergoing TAVI.
3. Patient has an estimated GFR <60ml/min/1.73m2.

Exclusion Criteria:

1. Patient has end-stage kidney disease requiring dialysis.
2. Emergent TAVI (planned before next working day).
3. Recent exposure to radiographic contrast agents (within 2 days prior to the TAVI).
4. Allergy to contrast agent.
5. Planned administration of dopamine, mannitol, fenoldopam or N-acetylcysteine during the intended time of the study.
6. Need for continuous hydration therapy (e.g. sepsis).
7. Multiple myeloma.
8. Contra-indication to sodium bicarbonate.