What are the new guidelines for preventing perioperative myocardial infarction (MI) in high-risk patients?

Perioperative MI Prevention Guidelines

For high-risk patients undergoing noncardiac surgery, continue beta-blockers in patients already taking them (Class I), start statins at least 30 days preoperatively (Class I for continuation, Class IIa for vascular surgery), and maintain antiplatelet therapy perioperatively unless bleeding risk is prohibitive. 1

Beta-Blocker Therapy

Mandatory Continuation (Class I)

• Patients already on beta-blockers must continue them throughout the perioperative period 1
• Withdrawal increases 1-year mortality dramatically (HR: 2.7) compared to continuous use 1
• Postoperative discontinuation carries 50% mortality versus 1.5% with continuation 1

Initiation Strategy (Class IIa)

• Start beta-blockers in patients with:
  • Inducible ischemia on preoperative testing undergoing vascular surgery 1
  • Known coronary artery disease or ≥3 clinical risk factors undergoing high-risk surgery 1
  • Multiple clinical risk factors undergoing vascular surgery 1

Dosing Protocol

• Initiate bisoprolol 2.5-5 mg daily starting 7-30 days before surgery 1, 2
• Titrate to achieve resting heart rate 50-60 bpm preoperatively 1
• Maintain heart rate <70-80 bpm intraoperatively and postoperatively 1
• Long-acting formulations superior to short-acting 1

Critical Pitfall

• Do NOT initiate beta-blockers de novo on the day of surgery or in emergency settings - this increases stroke and death rates 3, 4
• Starting therapy the day before surgery provides inadequate beta-blockade and may worsen outcomes 1

Statin Therapy

Mandatory Continuation (Class I)

• All patients currently taking statins must continue them perioperatively 1
• Withdrawal >4 days postoperatively independently predicts myonecrosis 1

Initiation Recommendations (Class IIa)

• Start statins for all patients undergoing vascular surgery regardless of risk factors 1
• Fluvastatin 80 mg daily or atorvastatin 20 mg daily 1, 2
• Ideally initiate 30 days before surgery 1, 3, 2

Evidence Base

• 59% mortality reduction in vascular surgery (1.7% vs 6.1%) 1
• 44% mortality reduction across all noncardiac surgery (2.2% vs 3.2%) 1
• Mechanisms: pleiotropic effects including endothelial stabilization, reduced inflammation, and plaque stabilization 1

For Intermediate-Risk Patients (Class IIb)

• May consider statins for patients with ≥1 clinical risk factor undergoing intermediate-risk procedures 1

Antiplatelet Therapy Management

Continuation Strategy

• Continue aspirin perioperatively for secondary prevention unless bleeding risk is very high (e.g., intracranial surgery) 5
• Dual antiplatelet therapy should continue in patients with recent coronary stents 1

Timing After Coronary Intervention

• Delay elective surgery:
  • ≥14 days after balloon angioplasty 1
  • ≥30 days (4-6 weeks) after bare-metal stent 1
  • ≥6-12 months after drug-eluting stent 1

Urgent Surgery in Stented Patients (Class IIa)

• Continue aspirin if possible 1
• Restart thienopyridine as soon as possible postoperatively 1

Risk Stratification Framework

Revised Cardiac Risk Index (Lee Index)

Use to quantify perioperative cardiac risk based on: 3

• High-risk surgery (vascular, intraperitoneal, intrathoracic)
• Ischemic heart disease
• Congestive heart failure
• Cerebrovascular disease
• Insulin-dependent diabetes mellitus
• Renal failure (creatinine >2 mg/dL)

Management Algorithm by Risk Score

• 0 risk factors: No routine beta-blocker or stress testing needed 3
• 1-2 risk factors: Consider low-dose beta-blocker 1 month preoperatively; stress testing only delays surgery without benefit 3
• ≥3 risk factors: Mandatory beta-blocker therapy; stress testing only if surgery can be delayed 30 days for medical optimization 3

Coronary Revascularization (Class III)

Routine prophylactic coronary revascularization is NOT recommended before noncardiac surgery in stable coronary artery disease 1

• Revascularization does not decrease MI or death rates at 1 month or 6 years 3
• Only perform revascularization for standard indications (left main disease, 3-vessel disease, high-risk unstable angina) 1

Additional Considerations

RAAS Inhibitors

• Can generally be continued perioperatively if patients are hemodynamically stable with normal renal function and electrolytes 5, 6
• Recent evidence suggests continuation may not increase risk 6

Stress Testing

• NOT routinely recommended - does not predict which vessels to revascularize or prevent MI/death 3
• Only indicated for unstable angina, active arrhythmia, or ≥3 risk factors when surgery can be delayed for optimization 3