What are the anesthesia considerations for a cardiac patient undergoing non-cardiac surgery?

Anesthesia Considerations in Cardiac Patients for Non-Cardiac Surgery

Pre-operative Risk Stratification Algorithm

All cardiac patients undergoing non-cardiac surgery must undergo systematic risk assessment following a stepwise approach that prioritizes urgency, cardiac stability, surgical risk, and functional capacity. 1

Step 1: Determine Urgency

• Urgent/Emergency surgery: Proceed directly to surgery with optimal medical management and perioperative monitoring—do not delay for cardiac testing 1
• Elective surgery: Continue systematic evaluation 1

Step 2: Screen for Active/Unstable Cardiac Conditions

If any of the following are present, surgery must be postponed and a multidisciplinary team should optimize the patient before proceeding: 1

• Unstable angina
• Acute heart failure or decompensated heart failure
• Significant arrhythmias
• Severe valvular disease
• Recent myocardial infarction (<30 days)

Step 3: Classify Surgical Risk

Surgical procedures are stratified into three risk categories for 30-day cardiac death or MI: 1

• Low risk (<1%): Proceed to surgery with baseline ECG if clinical risk factors present 1
• Intermediate risk (1-5%): Continue to functional capacity assessment 1
• High risk (>5%): Continue to functional capacity assessment 1

Step 4: Assess Functional Capacity

Functional capacity is measured in metabolic equivalents (METs): 1

• ≥4 METs (good functional capacity): Proceed to surgery without further testing 1
  • For vascular surgery specifically, initiate statin therapy preoperatively 1
• <4 METs (poor functional capacity): Proceed to cardiac risk factor assessment 1

Step 5: Evaluate Clinical Risk Factors

Count the number of clinical risk factors present: 1

• Ischemic heart disease
• Heart failure
• Cerebrovascular disease
• Diabetes mellitus requiring insulin
• Renal insufficiency (creatinine >2 mg/dL)

Management based on risk factor count:

• <2 risk factors + intermediate-risk surgery: Consider echocardiography and biomarkers (BNP/troponin) for prognostic information 1
• ≥3 risk factors OR high-risk surgery: Consider non-invasive stress testing to guide perioperative management and surgical decision-making 1

Step 6: Interpretation of Stress Testing

If extensive stress-induced ischemia is detected, individualized management is required weighing surgical benefit against cardiac risk, considering medical optimization and/or coronary revascularization. 1

Pre-operative Medical Optimization

Beta-Blocker Therapy

Beta-blockers should be continued in patients already taking them for angina, arrhythmias, or hypertension. 1

• For patients with known ischemic heart disease or myocardial ischemia undergoing intermediate/high-risk surgery: Initiation of titrated low-dose beta-blocker regimen may be considered, starting 30 days to at least 2 days before surgery 1
• Target heart rate: 60-70 bpm with systolic blood pressure >100 mmHg 1
• Contraindication: Do not give beta-blockers to patients with absolute contraindications 1

ACE Inhibitor Therapy

In patients with heart failure and systolic dysfunction, ACE inhibitors should be considered and initiated at least 1 week before surgery. 1

Statin Therapy

For patients undergoing vascular surgery with or without clinical risk factors, statin use is reasonable and should be initiated preoperatively. 1

Antiplatelet Management in Patients with Coronary Stents

Timing of surgery after stent placement is critical to minimize stent thrombosis risk: 1

• Balloon angioplasty: Surgery can be performed >2 weeks after intervention with aspirin continuation 1
• Bare-metal stent (BMS): Surgery can be performed >4 weeks after intervention; dual antiplatelet therapy (DAPT) should be continued for at least 4 weeks 1
• Drug-eluting stent (DES): Surgery should be delayed 6 months for new-generation DES or 12 months for old-generation DES 1

If urgent surgery is required within 4-6 weeks of stent placement, DAPT should be continued unless bleeding risk outweighs stent thrombosis risk. 1

Aspirin continuation versus discontinuation must be individualized based on bleeding risk versus thrombotic risk. 1

Intraoperative Anesthetic Management

Choice of Anesthetic Agent

For cardiac patients, volatile anesthetic agents (particularly sevoflurane) are preferred over total intravenous anesthesia due to cardioprotective effects. 1, 2

• Sevoflurane with remifentanil (0.15-0.25 μg/kg/min) or fentanyl (1-2 μg/kg slow IV) provides balanced anesthesia with minimal hemodynamic impact 2
• Maintenance: Sevoflurane 0.5-1 MAC with opioid infusion maintains hemodynamic stability 2
• Cardioprotective benefits: Volatile anesthetics decrease troponin release, enhance left ventricular function, and reduce ICU length of stay compared to propofol 1, 2

However, either volatile anesthetic or total intravenous anesthesia is reasonable, with choice determined by factors other than MI prevention alone. 1

Propofol Considerations in Cardiac Patients

If propofol is used, critical precautions are mandatory: 3

• Avoid rapid bolus administration—propofol causes dose-dependent arterial hypotension (>30% decrease), decreased cardiac output, and apnea 3
• Slow induction rate: Approximately 20 mg every 10 seconds (0.5-1.5 mg/kg total) 3
• Maintenance infusion: Not less than 100 mcg/kg/min when propofol is primary agent; reduce by 30-50% after first 15 minutes 3
• Elderly/debilitated patients: Require significantly lower doses due to higher peak plasma concentrations and increased cardiorespiratory depression risk 3
• Propofol should NOT be used with high-dose opioid technique in cardiac patients as this increases hypotension likelihood 3

Regional Anesthesia Considerations

Neuraxial anesthesia (epidural) for postoperative pain relief can be effective to reduce MI in patients undergoing abdominal aortic surgery. 1

Preoperative epidural analgesia may be considered to decrease cardiac events in patients with hip fracture. 1

Intraoperative Monitoring

Routine invasive monitoring is NOT recommended, but selective use is appropriate: 1

• Pulmonary artery catheterization: May be considered when underlying conditions significantly affecting hemodynamics cannot be corrected preoperatively, but routine use is NOT recommended 1
• Transesophageal echocardiography (TEE): Emergency use is reasonable for acute, persistent, life-threatening hemodynamic instability; routine use is NOT recommended 1
• Prophylactic intravenous nitroglycerin: NOT effective in reducing myocardial ischemia and is NOT recommended 1

Temperature Management

Maintenance of normothermia is recommended to reduce perioperative cardiac events, except during periods when mild hypothermia provides organ protection. 1

Hemodynamic Goals During Anesthesia

Optimize coronary perfusion by controlling: 4

• Heart rate (target 60-70 bpm)
• Maintain diastolic/mean arterial pressure
• Optimize right and left ventricular end-diastolic pressures
• Avoid excessive fluid administration that may cause fluid overload in compromised cardiac function 2

Management of Intraoperative Myocardial Infarction

If MI occurs intraoperatively, immediate recognition and differentiation of MI type is critical: 4, 5

Immediate Actions

• Obtain troponin measurement and serial ECGs immediately 4, 5
• Perform urgent echocardiography to assess ventricular function and detect mechanical complications 4
• Optimize hemodynamics: Control heart rate, maintain arterial pressure, optimize ventricular filling pressures 4

Medical Therapy

All patients with perioperative MI should receive: 4, 5

• Aspirin: Initiate immediately and continue indefinitely unless bleeding prohibitive 4, 5
• Beta-blockers: Start immediately targeting heart rate 60-70 bpm and systolic BP >100 mmHg 4, 5
• ACE inhibitors: Especially beneficial in low ejection fraction or anterior infarctions 4, 5
• High-intensity statin therapy 5

Revascularization Decision

Type 1 MI (acute coronary occlusion) with STEMI or hemodynamic instability: Consider emergency coronary angiography and PCI if bleeding risk permits, or emergency CABG if PCI fails or anatomy suitable 4, 5

Type 2 MI (supply-demand mismatch): Focus on correcting underlying causes (hypotension, tachycardia, anemia, hypoxemia) rather than invasive intervention 4, 5

Fibrinolytic therapy is CONTRAINDICATED in the immediate postoperative period due to substantial bleeding risk. 4

Common Pitfalls to Avoid

• Do not perform routine preoperative cardiac testing in low-risk patients—it is time-consuming, costly, and does not improve outcomes 6
• Do not use rapid bolus induction in elderly or hemodynamically compromised patients—this causes severe cardiorespiratory depression 2, 3
• Do not routinely use pulmonary artery catheters—they do not improve outcomes 1
• Do not administer prophylactic nitroglycerin—it is ineffective and may cause hypotension 1
• Do not delay urgent surgery for cardiac testing—proceed with optimal medical management 1
• Do not perform elective surgery within 4-6 weeks of coronary stent placement—stent thrombosis risk is prohibitive 1

Post-operative Management

All patients who sustain perioperative MI must have: 5

• Left ventricular function evaluated with echocardiography before discharge
• Standard post-infarction medical therapy prescribed (aspirin, beta-blockers, ACE inhibitors, high-intensity statins)
• Risk stratification with stress testing
• Aggressive cardiovascular risk factor modification

Perioperative MI carries extremely high mortality risk (40-70% for symptomatic MI) with nearly one-third mortality or readmission rate at 30 days. 4, 5