A Prospective, Comparative Study of Intravenous Iron Isomaltoside 1000 (Monofer®) Administered by Infusions to Non-Anaemic Patients Undergoing Elective or Sub-Acute Coronary Artery Bypass Graft, Valve Replacement or a Combination Thereof

Inclusion Criteria: 1. Men and women, aged more than 18 years. 2. Subjects undergoing elective or sub-acute CABG, valve replacement or a combination thereof 3. Female Hb ≥ 12.0 g/dl (7.45 mmol/l), Male Hb ≥ 13.0 g/dl (8.1 mmol/l). 4. Willingness to participate after informed consent. Exclusion Criteria: 1. Subjects receiving blood transfusion less than 30 days before screening and/or during the elective or sub-acute CABG, valve replacement, or a combination thereof. 2. Iron overload or disturbances in utilization of iron (e.g. haemochromatosis and haemosiderosis). 3. Serum Ferritin \> 800 ng/ml. 4. Known hypersensitivity to any excipients in the investigational drug products. 5. Patients with a history of multiple allergies. 6. Decompensated liver cirrhosis and hepatitis. 7. Alanine Aminotransferase (ALT) \> 3 times normal upper value. 8. Acute infections (assessed by clinical judgement). 9. Rheumatoid arthritis with symptoms or signs of active joint inflammation. 10. Pregnant or nursing. (To avoid pregnancy, women have to be postmenopausal (at least 12 months must have elapsed since last menstruation), surgically sterile, or women of child bearing potential must use one of the following contraceptives during the whole study period and after the study has ended for at least 5 times plasma biological half-life of the investigational medicinal product: Contraceptive pills, Intrauterine Devices (IUD), contraceptive depot injections (prolonged-release gestagen), subdermal implantation, vaginal ring, and transdermal patches). 11. Participation in any other clinical trial where the study drug has not passed five half-lives prior to screening. 12. Untreated Vitamin B12 or folate deficiency. 13. Other IV or oral iron treatment within 4 weeks prior to screening visit. 14. Erythropoietin treatment within 4 weeks prior to screening visit 15. Impaired renal function defined by se-creatinin \> 150 µmol/l