Measurement Of NT-proBNP to Predict Outcomes in Surgery

The team is investigating whether N-terminal pro B-type natriuretic peptide (NT-proBNP) and other cardiac markers are useful for predicting outcomes for patients undergoing vascular surgery. By measuring NT-proBNP before and after surgery, the investigators may be able to determine which patients are at risk of an adverse outcome, such as a heart attack or death.

Almost 1 in 5 patients who have elective major vascular surgery experience death or a myocardial infarction (MI) at 18 months post-surgery. Research has shown that peri-operative interventions may improve outcomes for high-risk patients. Cardiac bio-markers may be used to identify these high-risk patients, in particular pre- and post-operative NT-proBNP.

Mahla found that by comparing surgery outcomes with NT-proBNP concentrations peri-operatively, high-risk patients could be identified and subsequent therapeutic decisions could be made to minimise adverse outcomes.

Van Kimmenade evaluated patients with acute heart failure and found that galectin-3 (Gal-3) was the best predictor of 60-day mortality compared with NT-proBNP and apelin (another cardiac marker), whereas NT-proBNP was the most useful for diagnosing HF. The authors also found that the combination of both markers (Gal-3 and NT-proBNP) have an even higher predictive value for outcome.

The predictive role of troponin I (cTnI) has been observed in a paper by Bursi et al. (2005) where patients undergoing elective major vascular surgery were stratified using the American College of Cardiology/American Heart Association (ACC/AHA) guidelines and followed up over a period of 24 months. Patients in every group with an elevated post-operative cTnI (≥100ng/L) were at greater risk of either MI or death.

The successful identification of high-risk patients can go on to have interventional risk-reducing pharmacological, therapeutic, diagnostic, or observational measures.

Prevention of cardiovascular events, particular for an aging population, can have positive impact on both the patient and society as a whole as it may result in patients maintaining their independence, avoiding major illness, avoiding nursing home care and living longer.

Eligibility Criteria:
Inclusion Criteria:

* Patients who are equal to or over 18 years old
* Patients scheduled to undergo elective surgery for the following procedures:
* Infrainguinal arterial reconstruction
* Aortic aneurysm
* Aorto-bifemoral bypass / or aortic endarterectomy
* Femoro-popliteal bypass
* Femoro-distal bypass
* Femoral endarterectomy
* Femoro-femoral crossover
* Axillo-femoral bypass
* Elective carotid surgery
* Patients having either general or regional anaesthesia for their surgery

Exclusion Criteria:-

* Patients undergoing emergency surgery
* Those who are unable or unwilling to give informed consent
* Patients with unstable coronary syndromes (acute or recent MI with evidence of important ischemic risk by clinical symptoms or stress testing or unstable or severe angina pectoris)
* Patients with decompensated heart failure (new onset shortness of breath and rales together with echocardiographic evidence of cardiac dysfunction or deterioration of chronic heart failure despite heart failure therapy)
* Patients with chronic atrial fibrillation