The prognostic implication of perioperative cardiac enzyme elevation in patients with fractured neck of femur: A systematic review and meta-analysis

BACKGROUND

Neck of Femur (NOF) fractures are a common injury in comorbid elderly patients which are associated with increased rates of morbidity and mortality following fracture. Because of their injury, patients can experience reductions in quality of life and independent living leading to transfer to nursing home or dependent levels of care. Numerous factors are associated with either complications or reductions in survival following fractured NOF. From the VISION cohort there is evidence that troponin elevation in the post-operative period following a diverse range of non-cardiac surgical procedures may lead to an increased risk of mortality in the absence of classical ischaemic or cardiac symptoms. The aim of this systematic review and meta-analysis is to validate the utility of perioperative troponin elevation as a prognostic indicator for mortality and cardiac morbidity in those with fractured NOF.

METHODS

The PRISMA guidelines for the conduct of meta-analyses were followed. An electronic search was conducted of the EMBASE, MEDLINE (Ovid) and Biosis databases. Studies were included for analysis if they stratified outcomes by perioperative troponin elevation in surgically managed fractured NOF and reported sufficient data on troponin elevation and mortality following surgery. Primary and secondary outcomes assessed were all-cause post-operative mortality and a composite measure of cardiac complications (myocardial infarction, cardiac failure and arrhythmia) respectively.

RESULTS

Eleven studies met inclusion criteria giving a total of 1363 patients. Overall, 497 patients (36.5%) experienced an elevation in troponin levels following surgery. Perioperative troponin elevation was significantly associated with all-cause mortality (OR 2.6; 95% CI 1.5 - 4.6; p <0.001) and cardiac complications (OR 7.4; 95% CI 3.5 - 15.8; p <0.001). Patient factors significantly associated with troponin elevation included pre-existing coronary artery disease, cardiac failure, hypertension, previous stroke and previous myocardial infarction.

CONCLUSION

Perioperative troponin elevation is significantly associated with increased mortality and post-operative cardiac complications following fractured NOF and may be a useful prognostic indicator in these patients. Future research should further stratify patients by the magnitude of troponin elevation and further refine the risk factors.