About 8-15% of patients with coronary artery disease sustain a postoperative myocardial ischemic event annually.
Associated mortality rate of 17-42%.
Incidence 2-3% in patients undergoing major noncardiac surgery.
Perioperative myocardial infarction is an important complication after cardiac surgery that leads to excessive perioperative mortality, and may be caused by inadequately treated preoperative ischemia, insufficient interoperative myocardial protection, or untoward surgical events such as incomplete revascularization, graft failure, or embolization.
The incidence of perioperative myocardial infarction is about 0.9%.
Mortality in high-risk groups such as those undergoing vascular surgery can be as high as 34%.
Fatal perioperative myocardial infarction commonly associated with advanced left main coronary artery disease and or three-vessel disease.
Activation of neurohumoral pathways, increase in catecholamines levels, decrease in endogenous tissue plasminogen activator, increased shear stress, platelet activation and possibly coronary artery spasm proposed mechanism of plaque disruption.
Treatment with beta-blockers in the perioperative period can decrease the incidence of myocardial infarction and death after noncardiac surgery in high-risk but not low risk patients.
Risk of acute myocardial infarction following total hip or knee replacement was elevated during the first two weeks after the procedure (Lalmohamed A et al).
In the above study thee absolute six-week risk of acute myocardial infarction was 0.51% for hip replacement, and 0.21% for knee replacement.
In the above studies the risk of AMI is substantially increased in the first two weeks after THR, 25-fold, and TKR, 31-fold, surgery compared with controls.
Risk assessment of AMI should be considered during the first six weeks after total hip replacement surgery and during the first two weeks after total knee replacement surgery.
POISE trial demonstrated use of B-blocker in patients undergoing noncardiac surgery reduces risk of cardiac death, nonfatal myocardial infarction or cardiac arrest, at the expense of increased risk of total mortality and stroke.
POISE-2 study demonstrated that using aspirin or clonidine did not reduce rate of composite death or nonfatal myocardial infarction in patients undergoing noncardiac surgery.