Ryding AD et al. Prognostic value of brain natriuretic peptide in noncardiac surgery: a meta-analysis. Anesthesiology. 2009 Aug;111(2):311-9. This metanalysis was designed to assess the prognostic value of elevated BNP or NT-proBNP levels in predicting mortality and major adverse cardiovascular events (MACE). Data from 15 publications (n=4,856) were included in the analysis. The metanalysis concluded that preoperative BNP elevation is associated with significantly increased risk of short-term MACE, cardiac mortality and all-cause mortality as well as longer term MACE and all cause mortality after major non-cardiac surgery. Generally accepted normal values for BNP (less than 100 pg/ml and NT-Pro-BNP (less than 300 pg/ml) would have a negative predictive value of at least 95-99% for short term MACE. The authors are hopeful that measurement of BNPs may be a simple method of risk stratifying patients before non-cardiac surgery and deciding which patients would benefit from further investigation of ventricular function and or inducible ischaemia.

Take home message: It is likely that BNP elevation identifies patients with impaired cardiac function or a significant ischaemic burden who may have poor outcomes when challenged with the haemodynamic and pro-inflammatory stresses of general anaesthesia and major surgery.

For related reading this month:
- Oscarsson A et al. N-terminal fragment of pro-B-type natriuretic peptide is a predictor of cardiac events in high-risk patients undergoing acute hip fracture surgery. Br J Anaesth. 2009 Aug;103(2):206-12.