BNP Evaluation Before Surgery Study: an Observational Study of Natriuretic Peptide Levels Prior to Surgery.

Identification of high-risk surgical patients requires risk stratification. Current clinical risk stratification tools, e.g. Revised Cardiac Risk Index (RCRI), only have a moderate ability to identify these patients. International guidelines, like Canadian Cardiovascular Society on perioperative cardiovascular risk assessment, advocate that all patients 45 yrs and older or patients >18y rs who have significant cardiovascular disease and who are coming for intermediate to high-risk surgery, should get natriuretic peptide (NP) testing. This is because raised preoperative B-type natriuretic peptides have a strong association with postoperative cardiac complications according to observational studies and meta-analyses.

However, in these patients with significant cardiovascular disease coming for intermediate to high-risk surgery it is unknown how many patients will actually have raised B-type natriuretic peptides. That is, which group of patients have an even higher risk in this already high-risk group. Natriuretic peptide (NP) testing is also expensive.

Further identification of patients that need NP testing will reduce costs and focus efforts on those patients who really need it.

Inclusion criteria

• Age ≥ 45 years of age.
• Undergoing intermediate or major non-cardiac surgery requiring an overnight stay in hospital.
• With at least one of the following criteria:

• History of ischaemic heart disease or peripheral vascular disease (coronary equivalent)
• History of stroke or transient ischaemic attack
• History of congestive cardiac failure
• Diabetes currently on an oral hypoglycaemic agent or insulin
• Serum creatinine >175 µmol/L (>2.0mg/dl)

Exclusion criteria

• Patient refusal to participate.
• Patients presenting for cardiac and obstetric or emergency surgery.