Approximately 30 million surgical procedures are performed each year in the United States, of which 1 million patients have coronary artery disease and another 2-3 million are at risk for coronary artery disease. These patients have a high incidence of perioperationmyocardialinfarction (PMI), cardiogenic death. In recent years, the incidence of coronary artery disease in China has been increasing year by year, while the number of patients with coronary artery disease or suspected coronary artery disease requiring non-cardiac surgery is increasing due to the continuous improvement of surgical and anesthesia methods and relaxation of surgical indications. The American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for perioperative cardiovascular assessment of noncardiac surgery, published in 1996 and updated in 2002 [2], aim to develop long- and short-term cardiac treatment plans and provide clinical risk predictions to optimize patient management. . The diagnosis and management of PMI in patients undergoing noncardiac surgery is discussed in the context of the guidelines.
The incidence of PMI in adults undergoing noncardiac surgery has been estimated to be 0.15%. The recurrence of PMI after surgery for old myocardial infarction is about 6%. One study found that the incidence of postoperative PMI was 4.1% in coronary artery disease (risk stratified as high risk), 0.8% in those with peripheral vascular disease but lacking evidence of coronary artery disease (intermediate risk), and 0% in those with high risk factors for atherosclerosis but without manifestations of atherosclerosis (low risk). Patients with coronary artery disease who underwent interventions for larger procedures had a PMI of 2.7% and an overall mortality rate of 3.3%. The two rates were 0.8% and 1% for those who underwent similar surgery without coronary artery disease. 50% of PMI patients were painless, which is higher than the 20%-40% of general myocardial infarction painless patients [2]. 10%-15% of PMI morbidity and mortality are similar to non-surgical procedures.
The pathophysiological alterations and mechanisms of PMI are not yet clear.PMI mostly occurs in the first three days after surgery, which is also the most dangerous period for thrombosis. However, surgical stimulation and postoperative pain cause a large secretion of catecholamines in patients, and elevated heart rate and blood pressure lead to an imbalance between postoperative diffuse myocardial oxygen supply and oxygen demand, while the postoperative hypercoagulable state further promotes plaque rupture and intracoronary thrombosis. Therefore, plaque rupture combined with thrombosis may be an important pathogenesis of PMI.
I. Perioperative cardiac risk assessment: including patient assessment and assessment of surgical risk.
1. Cardiac risk stratification: ACC/AHA guidelines classify predictors of increased perioperative cardiovascular risk into 3 categories. High risk: Recent acute coronary syndrome such as acute myocardial infarction (>265.2 μmol/L (3.0 mg/dl), elevated SGOT, chronic liver disease signs and bedridden for non-cardiac reasons.
2. Preoperative examination: The purpose is to identify the presence of heart disease, determine the severity and stability of the disease, etc. In addition to routine examinations, cardiac catheterization and cardiovascular angiography will be performed if necessary. The intensity of the tests is divided into I, IIa, IIb and III according to the recommended guidelines; I is a mandatory test, IIa is the best test, IIb is an optional test, and III is not necessary.
(1) Left ventricular function measurement.
Category I: If the heart failure is currently poorly controlled, it is not necessary to repeat the test if previous assessment has confirmed severe left ventricular function abnormalities.
Category IIa: Previous heart failure with unexplained dyspnea.
Class III: No previous heart failure, as a routine examination of left ventricular function.
(2) 12-lead electrocardiogram.
Intraoperative and postoperative ST-segment changes suggest that myocardial ischemia is a strong predictor of the occurrence of PMI and a long-term risk factor for cardiogenic death. Resting ECG in low-risk surgical patients does not identify increased perioperative risk, but abnormal ECG is a clinical predictor of perioperative and long-term cardiovascular risk in intermediate- and high-risk patients.
Class I: Moderate-to-high-risk patients proposed for moderate-to-high-risk surgery with recent chest pain or ischemic attack.
Category IIa: asymptomatic diabetes mellitus.
Category IIb: Previous PCI, male >45 years, female >55 years or multiple atherosclerotic risk factors, previous hospitalization for cardiac disease.
Category III: Asymptomatic individuals who have undergone low-risk procedures.
(3) Exercise or drug loading test.
Category I: adults with suspected or confirmed coronary artery disease for diagnostic evaluation; evidence of myocardial ischemia prior to coronary angioplasty; evaluation of treatment; prognostic evaluation of acute coronary syndrome.
Class IIa: When subjective assessment is not credible to evaluate exercise capacity.
Class IIb: Diagnosis of patients with low and high risk factors, resting ST-segment depression.