CAVIAR is a multicentre prospective observational study. Centres for cardiac and vascular surgery assess and manage patients in different ways before surgery. Some centres have introduced the use of intravenous iron therapy for patients with anaemia in the preoperative setting. Consequently regional variation exists in the assessment and management of patients before cardiac and vascular surgery. We aim to observe and measure these differing pathways and observe if there is variation in iron deficiency and anaemia and the impact of these variables on patient cardiorespiratory function as well as post-operative outcomes.

[Sub-Study] For patients who are receiving intravenous iron therapy as part of their routine clinical care, we wish to observe this effect in more detail. We will assess the impact of the treatment on well-being, blood count and fitness. Information will be collected through Quality of Life questionnaires, total haemoglobin mass test (via blood collection) and fitness testing.

Inclusion Criteria:

1. Male and female adults aged 18 years or older

2. Screening [Hb] < 120 g/L (for females) or < 130g/L (for males)

3. Undergoing elective cardiac OR vascular surgery:

   • Coronary artery bypass (CABG), or valvular surgery, or combined CABG and valve surgery.
   • Repair or replacement of thoracic or abdominal aorta (open or endovascular).

4. Able to provide informed consent

5. (if applicable) Able to perform CPET or 6MWT if consented to take part in the sub study

Exclusion Criteria:

1. Pregnancy or lactation
2. Adults with known underlying history of learning disabilities, or adults who do not have mental capacity to consent for themselves
3. Prisoners
4. Renal dialysis (current or planned within the next 12 months)

Patients requiring major cardiac or vascular surgery will be identified from routine clinical care. Most patients are routinely referred for pre-operative assessment, although local protocols vary between centres. Assesments at the pre-operative assessment clinic (PAC) may include (but not limited to) routine blood tests (full blood count, urea and electrolytes, etc.), history and examination, cardiorespiratory fitness assessment by 6 minute walk test (6MWT) or cardiopulmonary exercise testing (CPET). In some centres, patients with anaemia will receive intravenous iron at PAC or in a separate anaemia clinic.