What are the primary goals of anesthesia in patients with Ischemic Heart Disease (IHD)?

Anesthesia Goals in Ischemic Heart Disease

The primary goals of anesthesia in patients with IHD are to maintain myocardial oxygen supply-demand balance by preventing tachycardia, preserving coronary perfusion pressure, and avoiding perioperative myocardial ischemia and infarction. 1, 2

Core Hemodynamic Targets

Heart Rate Control

• Maintain target heart rate of 60-70 beats per minute to maximize diastolic coronary perfusion time and minimize myocardial oxygen demand 1
• Beta-adrenoceptor antagonists are the most effective means to prevent deleterious increases in heart rate throughout the perioperative period 2
• Tachycardia is particularly dangerous as it reduces oxygen supply to ischemic myocardium while simultaneously increasing oxygen demand 2

Blood Pressure Management

• Maintain systolic blood pressure >100 mmHg to preserve coronary perfusion pressure 1
• Avoid mean arterial pressure <60 mmHg for cumulative periods >30 minutes, as prolonged hypotension is associated with adverse outcomes 1
• Decreases in diastolic arterial pressure in the presence of severe coronary stenoses will critically reduce myocardial blood flow 2
• Preservation of perfusion pressure may require fluid administration, phenylephrine, or reduction in anesthetic concentration 2

Myocardial Oxygen Balance Strategy

Reduce Oxygen Demand

• Decrease myocardial contractility using beta-adrenoceptor antagonists or volatile anesthetics to reduce oxygen consumption 2
• Prevent sympathetic nervous system activation by reducing preoperative anxiety and blocking the stress response with appropriate opioids or volatile anesthetics 2
• Continue anti-ischemic therapy (beta-blockers, calcium antagonists, nitrates) throughout the perioperative period 3

Optimize Oxygen Supply

• Preserve coronary perfusion pressure as detailed above 2
• Consider coronary vasodilation with glyceryl trinitrate (GTN) when indicated, and do not withhold it 4
• Maintain adequate diastolic time through heart rate control 2

Anesthetic Technique Selection

General vs. Regional Anesthesia

• Either volatile anesthetic agents or total intravenous anesthesia is reasonable, as no cardioprotective benefit has been demonstrated for either approach in noncardiac surgery 1
• Neuraxial anesthesia (epidural or spinal) shows no cardioprotective benefit over general anesthesia for intraoperative management, with equivalent 4% MI rates in comparative studies 1
• The choice of anesthetic technique should be determined by surgical factors, patient comorbidities, and patient preferences rather than cardiac protection alone 1

Monitoring Requirements

• All patients with IHD should have plethysmographic or arterial pressure monitoring during procedures, as electrocautery may interfere with ECG recording 1
• Use optimal ECG lead configurations for continuous ischemia monitoring, recognizing that sensitivity is not 100% 4
• Consider goal-directed therapy in patients with high cardiac and surgical risk 1

Perioperative Medical Management

Beta-Blocker Therapy

• Initiate beta-blocker therapy ideally between 30 days and at least 2 days before surgery and continue postoperatively 1
• Beta-blockers are definitively proven to prevent intraoperative myocardial ischemia, rhythm disorders, and pathologic arterial pressure rises 3
• Early use of beta-blocking drugs should be considered even with normal blood pressures and heart rates 4

Analgesic Considerations

• Avoid NSAIDs (especially COX-2 inhibitors) as first-line analgesics in patients with IHD, as they promote heart failure, renal failure, and thromboembolic events 1
• Consider neuraxial analgesia for postoperative pain control when not contraindicated 1

Critical Pitfalls to Avoid

Silent Myocardial Ischemia

• Recognize that ischemia commonly occurs without hemodynamic aberrations throughout the perioperative period, with the greatest incidence and severity in the postoperative period when anesthetic effects dissipate 5
• Continuous monitoring is essential as ischemia may occur even with appropriately used anesthetic techniques 5

Timing Considerations

• Anesthesiologic risk is minimal six months after myocardial infarction in the presence of stable angina 3
• The duration since previous MI and severity of angina manifestations determine perioperative risk 3

Postoperative Monitoring

• Consider measuring high-sensitivity troponin and natriuretic peptides postoperatively in high-risk patients (METs ≤4, revised cardiac risk index >1 for vascular surgery or >2 for non-vascular surgery) 1
• Early identification of postoperative complications with aggressive management may decrease morbidity and mortality 1