Myocardial injury after non-cardiac surgery: Time to shed the ignorance
Perioperative cardiovascular complications are common and place a significant burden on public healthcare systems. A large proportion of such complications are due to a new clinical entity, i.e. myocardial injury after non-cardiac surgery (MINS). It is important to understand MINS, its prognosis and management in the perioperative period. A literature review of MINS was done. MINS is defined as an elevated postoperative cardiac troponin level that was considered as resulting from myocardial ischaemia without evidence of a non-ischaemic cause for the troponin elevation. The perioperative milieu (surgical stress response, sympathetic activation, hypercoagulability, hypotension, bleeding, anaemia and pain) contributes to the pathophysiology of a relative myocardial hypoperfusion and ischaemia, which differentiates MINS from myocardial infarction in non-surgical patients. Globally, >7% of adults ≥45 years of age suffer MINS, with South African (SA) studies confirming similar event rates. More than 80% of MINS patients are asymptomatic for myocardial ischaemia, and therefore would not fulfil the universal definition of myocardial infarction, despite having a similar prognosis to those with the latter condition. Accurate diagnosis of MINS therefore relies on routine daily postoperative cardiac troponin surveillance for 48 - 72 hours postoperatively in patients with a >5% risk of major perioperative cardiovascular complications. This approach is cost-effective in SA. One in 10 patients with MINS dies within 30 days of surgery, and 1 in 5 develops major cardiovascular complications. Short- and long-term mortality could be improved by simple treatment strategies, including cardiovascular therapy intensification, and by ensuring aspirin use and statin therapy. All recommendations promote the involvement of a multidisciplinary team. MINS is a common, serious perioperative cardiovascular complication with public healthcare implications that has been underappreciated in SA. A multidisciplinary approach with simple treatment strategies should be adopted.