Patients with impaired renal function are at elevated risk for development of contrast-medium induced acute kidney injury (CI-AKI). CI-AKI is associated with increased risk for cardiovascular morbidity and mortality. Effective CI-AKI prevention strategies are needed.

The RenPro-II-WINE Trial was designed to test the hypothesis whether moderate red wine consumption prior to contrast-medium use is effective in CI-AKI prevention.

Consecutive patients with impaired renal function undergoing elective coronary angiography will be assigned in one of four treatment arms: a. control patients receiving standard care b. patients receiving standard care plus red wine c. patients receiving standard care plus white wine d. patients receiving standard care plus beer This study will give important answers on how to prevent CI-AKI in patients with impaired renal function undergoing contrast media exposure.

Inclusion Criteria:

• age >= 18 years
• impaired renal function (baseline estimated glomerular filtration rate of <60 ml/min)
• at least three of following comorbidities: hypertension, diabetes mellitus without insulin therapy, heart failure NYHA III and/or left ventricular ejection fraction <35%, peripheral artery disease, coronary artery disease

Exclusion Criteria:

• known alcohol addiction
• severe renal impairment (estimated glomerular filtration rate <15 ml/min and/or in chronic dialysis program
• Recent (<=30 days) contrast media exposure
• insulin therapy
• Patients enrolled in concomitant studies
• fertile women