Randomized controlled, single-center trial randomizing patients with chronic kidney disease and symptomatic severe aortic valve stenosis undergoing transcatheter aortic valve implantation (TAVI). Patients are randomized in a 1:1 ratio to periprocedural intravenous hydration matched to urine output using the RenalGuard system and to standard hydration. The purpose of the study is to test, wether the controlled intravenous hydration with the RenalGuard system is superior to standard hydration to prevent acute kidney injury after TAVI.

Acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) is associated with worse outcome. The RenalGuard system was developed to prevent AKI by a controlled furosemide-induced diuresis with matched isotonic intravenous hydration. It is based on the theory, that a high urinary output prevents contrast media-induced nephropathy (CIN).

The present study is a prospective, randomized trial to investigate wether a matched intravenous hydration using the RenalGuard system is superior to standard pre- and postprocedural intravenous hydration in patients with severe aortic valve stenosis and chronic kidney disease undergoing TAVI. Primary endpoint is the occurrence of AKI after TAVI.

Inclusion Criteria:

• Symptomatic severe aortic valve stenosis undergoing transcatheter aortic valve implantation
• Chronic kidney disease (baseline glomerular filtration rate ≤ 60 ml/min)
• Written informed consent

Exclusion Criteria:

• Hemodynamic instability
• Dialysis-dependent chronic kidney injury
• Emergency transcatheter aortic valve stenosis