What are the recent American Heart Association (AHA) guidelines for preventing myocardial infarction (MI) in patients undergoing non-cardiac surgery?

Prevention of Myocardial Infarction in Patients Undergoing Non-Cardiac Surgery: AHA/ACC Guidelines

Immediate Preoperative Medical Management

Continue statins perioperatively in all patients already taking them, and initiate statins in statin-naïve patients with atherosclerotic cardiovascular disease or elevated 10-year ASCVD risk who are undergoing vascular or elevated-risk surgery. 1

• Statin therapy reduces major adverse cardiac events (MACE) by approximately 60% in vascular surgery patients (composite endpoint reduced from 26% to 8% with atorvastatin 20 mg daily started 30 days preoperatively). 1
• Large cohort data demonstrates 9.9% lower surgical mortality in patients receiving perioperative lipid-lowering therapy. 1
• Statins should be initiated with intention for long-term continuation beyond the perioperative period, not just as a short-term intervention. 1

Continue beta-blockers in patients already taking them, but do NOT routinely initiate beta-blockers in beta-blocker-naïve patients, particularly within 1 day of surgery. 1

• Withdrawal of chronic beta-blockers increases 1-year mortality dramatically (HR: 2.7), and postoperative discontinuation carries 50% mortality versus 1.5% with continuation. 1
• However, initiating beta-blockers ≤1 day before surgery increases nonfatal stroke (RR: 1.76), hypotension (RR: 1.47), bradycardia (RR: 2.61), and all-cause mortality (RR: 1.30). 1
• The 2007 ACC/AHA guidelines recommend beta-blockers for patients at high cardiac risk due to ischemia on preoperative testing who are undergoing vascular surgery (Class IIa). 2

Continue aspirin perioperatively for secondary prevention unless bleeding risk is extremely high (e.g., intracranial surgery). 1

• Routine low-dose aspirin (100 mg/d) does not decrease cardiovascular events but does increase surgical bleeding in unselected patients. 3
• For patients with recent coronary stents, maintain dual antiplatelet therapy and delay elective surgery: ≥14 days after balloon angioplasty, ≥30 days (4-6 weeks) after bare-metal stent, ≥6-12 months after drug-eluting stent. 1

Consider omitting RAAS inhibitors 24 hours before elevated-risk surgery in patients with controlled hypertension to limit intraoperative hypotension (Class IIb). 1

• However, continue RAAS inhibitors perioperatively in patients taking them for heart failure with reduced ejection fraction (Class IIa). 1
• Meta-analysis shows more intraoperative hypotension with continuation but no difference in MACE. 1

Risk Stratification Algorithm

Step 1: Identify active cardiac conditions requiring evaluation and treatment BEFORE surgery (Class I, Level B). 2

Active cardiac conditions that mandate delay or cancellation of elective surgery include:

• Unstable coronary syndromes: Unstable or severe angina (CCS class III or IV), recent MI (>7 days but ≤30 days). 2
• Decompensated heart failure: NYHA class IV, worsening or new-onset HF. 2
• Significant arrhythmias: High-grade AV block, Mobitz II or third-degree heart block, symptomatic ventricular arrhythmias, supraventricular arrhythmias with uncontrolled ventricular rate (HR >100 bpm at rest), symptomatic bradycardia, newly recognized ventricular tachycardia. 2
• Severe valvular disease: Severe aortic stenosis (mean gradient >40 mmHg, valve area <1.0 cm², or symptomatic), symptomatic mitral stenosis. 2

Step 2: Assess functional capacity using metabolic equivalents (METs). 2

• Patients with excellent functional capacity (≥10 METs or ability to climb >2 flights of stairs) can proceed to surgery without further cardiac testing, even with elevated risk factors (Class IIa). 2
• Patients with poor functional capacity (<4 METs or inability to climb 2 flights of stairs) require further risk stratification. 2, 3
• Functional capacity assessment is more predictive than many noninvasive tests for perioperative risk. 3

Step 3: Stratify surgical risk. 2

• High-risk surgery: Emergent major operations, aortic and major vascular surgery, peripheral vascular surgery, prolonged procedures with large fluid shifts and blood loss. 2
• Intermediate-risk surgery: Carotid endarterectomy, major head and neck, intraperitoneal and intrathoracic, orthopedic, prostate surgery. 2
• Low-risk surgery: Endoscopic procedures, superficial procedures, cataract, breast surgery. 2

Step 4: Apply clinical risk indices (Revised Cardiac Risk Index). 2, 4

Clinical risk factors include:

• History of ischemic heart disease
• History of compensated or prior heart failure
• History of cerebrovascular disease
• Diabetes mellitus requiring insulin
• Chronic kidney disease (creatinine >2 mg/dL)
• High-risk surgery type 4

Step 5: Determine need for preoperative cardiac testing. 2

• Routine preoperative stress testing is NOT useful for low-risk noncardiac surgery (Class III, Level B). 2
• For patients with elevated risk and poor/unknown functional capacity undergoing high-risk surgery, pharmacological stress testing (dobutamine stress echo or myocardial perfusion imaging) is reasonable IF results will change management (Class IIa). 2
• Preoperative resting 12-lead ECG is reasonable for patients with known coronary disease or significant structural heart disease, except for low-risk surgery (Class IIa). 2
• Routine preoperative ECG is NOT useful for asymptomatic patients undergoing low-risk procedures (Class III). 2

Coronary Revascularization Strategy

Do NOT perform routine prophylactic coronary revascularization before noncardiac surgery in patients with stable coronary artery disease (Class III, Level B). 2, 1

• CABG is rarely indicated simply to "get a patient through" noncardiac surgery. 2
• Coronary revascularization before noncardiac surgery is ONLY indicated for standard indications independent of the planned surgery. 1

Coronary revascularization IS indicated before noncardiac surgery in the following situations (Class I, Level A): 2

• Significant left main coronary artery stenosis
• 3-vessel disease (survival benefit greater when LVEF <0.50)
• 2-vessel disease with significant proximal LAD stenosis and either LVEF <0.50 or demonstrable ischemia on noninvasive testing
• High-risk unstable angina or non-ST-elevation MI
• Acute ST-elevation MI 2

Postoperative Surveillance for MI

Measure troponin and obtain ECG when signs or symptoms of ischemia, MI, or arrhythmia are present (Class I). 1, 5

• Postoperative troponin measurement is recommended in patients with ECG changes or chest pain typical of acute coronary syndrome. 2
• Routine postoperative screening with troponin or ECG in asymptomatic high-risk patients has uncertain benefit (Class IIb). 1
• Postoperative troponin measurement is NOT recommended in asymptomatic stable patients who have undergone low-risk surgery (Class III). 2

Obtain ECGs at baseline, immediately after surgery, and on the first two postoperative days for patients with cardiovascular abnormalities undergoing high-risk procedures. 4

Management of Perioperative MI

All patients with perioperative MI should receive standard medical therapy including aspirin, beta-blockers, ACE inhibitors, and high-intensity statin therapy immediately. 5

• Aspirin should be initiated immediately and continued indefinitely unless bleeding risk is prohibitive. 5
• Beta-blockers reduce myocardial oxygen demand through heart rate and blood pressure control. 5
• ACE inhibitors are especially beneficial in patients with low ejection fractions or anterior infarctions. 5
• High-intensity statin therapy should be initiated or continued. 5

For perioperative STEMI (Type 1 MI with acute plaque rupture), consider invasive coronary angiography, carefully balancing bleeding and thrombotic risks (Class I). 5

• The 2024 ACC/AHA guidelines recognize that acute coronary occlusion requires rapid intervention. 5
• Angioplasty should be considered when symptomatic perioperative ST-segment elevation MI occurs due to sudden thrombotic occlusion. 2

For Type 2 MI (supply-demand mismatch), focus on correcting underlying causes such as hypotension, tachycardia, anemia, or hypertension. 5

All patients who sustain perioperative MI must have left ventricular function evaluated before hospital discharge. 5

Common Pitfalls

• Perioperative MI carries 40-70% mortality for symptomatic MI and substantially increases risk of future cardiac events. 5
• Patients aged ≥75 years have nearly double the risk of perioperative MI and MACE (9.5% vs 4.8% for younger adults). 3
• Patients with coronary stents have 6-fold higher risk of perioperative complications (8.9% vs 1.5% for those without stents). 3
• B-type natriuretic peptide level before surgery serves as an additional risk stratification factor beyond clinical indices. 4
• Long operations with hemodynamic instability requiring large-volume fluid replacement are associated with increased perioperative mortality. 4