What are the next steps for a patient with a history of cardiovascular disease, diabetes, hypertension, and impaired renal function, who has a borderline preoperative electrocardiogram (EKG) prior to high-risk surgery?

Management of Borderline Preoperative EKG in High-Risk Patient

In a patient with cardiovascular disease, diabetes, hypertension, and renal impairment facing high-risk surgery with a borderline preoperative EKG, further evaluation is reasonable to refine cardiovascular risk assessment before proceeding, focusing on functional capacity assessment and consideration of noninvasive stress testing if it will change perioperative management. 1

Initial Assessment Steps

Define "Borderline" EKG Findings

Compare the current EKG with previous tracings to determine if findings are new or chronic 1. Borderline abnormalities that warrant concern include:

• Nonspecific ST-T wave changes 1
• Minor T-wave inversions 1
• Left ventricular hypertrophy with strain pattern 2
• First-degree AV block 1
• Isolated premature ventricular contractions 2

Assess for Active Cardiac Conditions Requiring Surgery Delay

The following findings would mandate postponing elective surgery 2:

• Unstable or severe arrhythmias (symptomatic ventricular arrhythmias, high-grade AV block, newly recognized ventricular tachycardia) 2
• Acute decompensated heart failure 2
• Dynamic ST-segment changes suggesting active ischemia 3

If none of these active conditions are present, proceed with risk stratification. 2

Risk Stratification Algorithm

Calculate Clinical Risk Factors

This patient has 4 clinical risk factors 1:

• Known cardiovascular disease 1
• Diabetes mellitus 1
• Renal insufficiency 1
• Hypertension (implied by history) 1

Assess Functional Capacity

Functional capacity is more predictive than EKG findings alone. 2, 4

• If functional capacity ≥4 METs (can climb 2 flights of stairs): Patient can generally proceed to surgery despite borderline EKG findings 1, 4
• If functional capacity <4 METs: Noninvasive stress testing is reasonable if results will change management 1

For high-risk surgery with ≥3 clinical risk factors and poor functional capacity, stress testing is a Class IIa recommendation (reasonable to perform) 1, 2

Additional Preoperative Testing

Cardiac Biomarkers

Obtain troponin levels to rule out recent or acute myocardial damage, particularly given the borderline EKG 3. This establishes a baseline for postoperative comparison 1.

Left Ventricular Function Assessment

Given the multiple cardiovascular risk factors, assess LV function if: 1

• Patient has new or worsening dyspnea 1
• Physical examination suggests heart failure 1
• Suspected new or worsening ventricular dysfunction 1

Echocardiography is reasonable in patients with known heart failure and changing clinical status 1. However, routine LV function assessment in asymptomatic, clinically stable patients is not recommended 1.

When Stress Testing Changes Management

Stress testing should only be pursued if results would alter the approach to 1, 4:

• Perioperative medical therapy optimization 4
• Anesthesia technique selection 4
• Surgical approach or timing 4

Critical caveat: Stress testing does not predict which coronary artery to revascularize, and routine preoperative coronary revascularization does not decrease MI or death rates 5. Incidental Q-waves or bundle branch block should not automatically lead to coronary revascularization 1.

Perioperative Medical Optimization

Beta-Blocker Considerations

For patients with ≥1 risk factor, consider low-dose beta-blocker started 1 month before surgery (e.g., bisoprolol 2.5-5 mg daily, titrated to heart rate <70 bpm and systolic BP ≥120 mmHg) 5.

Major pitfall to avoid: High-dose beta-blockers (e.g., metoprolol succinate 100 mg) administered 2-4 hours before surgery increase stroke risk (1.0% vs 0.5%) and mortality (3.1% vs 2.3%) 4. Do not initiate high-dose beta-blockers acutely perioperatively 4.

Statin Therapy

All patients with atherosclerotic cardiovascular disease undergoing high-risk surgery should receive statins 4. Ideally start 30 days before surgery using long-acting formulations 5. Statins reduce postoperative cardiovascular complications and mortality (1.8% vs 2.3% without statins) 4.

Aspirin Management

Routine perioperative low-dose aspirin (100 mg daily) does not decrease cardiovascular events but does increase surgical bleeding 4. Decision should be individualized based on bleeding risk of the specific procedure 4.

Timing Considerations

When to Obtain Cardiology Consultation

Consult cardiology before proceeding if 2:

• New pathological Q-waves with unknown cardiac history (requires echocardiography) 2
• High-grade conduction abnormalities (Mobitz type II or complete heart block) 2
• Prolonged QT interval that may affect anesthetic selection 2
• Patient has ≥3 risk factors with poor functional capacity and stress testing is being considered 1

Optimal Timing for Surgery

If stress testing reveals significant ischemia requiring medical optimization, allow 30 days for medical therapy optimization before proceeding with surgery 5. This period allows for beta-blocker and statin initiation and titration 5.

Perioperative Monitoring Plan

Intraoperative Management

• Continuous ECG monitoring during surgery 3
• Hemodynamic monitoring appropriate for high-risk surgery 1

Postoperative Surveillance

• Serial postoperative ECGs, especially in first 48 hours 3
• Troponin monitoring at 24 and 48 hours after surgery 6
• Continuous cardiac monitoring for minimum 48-72 hours 6

The preoperative borderline EKG serves as a critical baseline for comparison if postoperative complications develop 1, making its documentation essential even if it doesn't change immediate management.

Common Pitfalls to Avoid

• Do not order routine stress testing without assessing functional capacity first 2. Patients with good functional capacity (≥4 METs) can proceed without stress testing 1.
• Do not pursue coronary revascularization solely to "get through surgery" 5, 7. Revascularization should only be performed for indications independent of the planned surgery 4.
• Do not fail to compare with previous EKGs 2. Chronic findings misinterpreted as acute may unnecessarily delay surgery 2.
• Do not start high-dose beta-blockers acutely before surgery 4. This increases stroke and mortality risk 4.