Perioperative Management of Angina

1. Preoperative Risk Stratification

Step 1: Urgency of Surgery

• Emergency surgery: Proceed immediately. Use clinical risk factors to guide perioperative monitoring; no cardiac workup required.
• Elective/urgent surgery: Full stepwise evaluation is warranted.

Step 2: Screen for Active Cardiac Conditions (Unstable Angina = Major Risk)

• Unstable angina (ACS) — highest priority; treat per ACS guidelines first
• Decompensated heart failure
• Significant arrhythmias
• Severe valvular disease

"The presence of unstable angina has been associated with a high perioperative risk of myocardial infarction (MI). The perioperative period is associated with a hypercoagulable state and surges in catecholamines." — Barash, Cullen, and Stoelting's Clinical Anesthesia, 9e

"Chronic stable (mild to moderate) angina does not seem to increase perioperative risk substantially." — Morgan and Mikhail's Clinical Anesthesiology, 7e

Step 3: Estimate MACE Risk (Clinical + Surgical)

1. High-risk surgery (intraperitoneal, intrathoracic, suprainguinal vascular)
2. History of ischemic heart disease
3. History of congestive heart failure
4. History of cerebrovascular disease
5. Diabetes mellitus on insulin
6. Preoperative creatinine >2.0 mg/dL

2. Perioperative Assessment Algorithm

Functional Capacity Assessment (METs)

• ≥4 METs without symptoms: Proceed to surgery — no further testing needed
• <4 METs or unknown capacity: Further testing warranted only if it will change management

3. Preoperative Investigations

"A normal dobutamine stress echocardiogram (DSE) or myocardial perfusion imaging (MPI) result suggests a low risk for perioperative cardiac complications." — Barash, Clinical Anesthesia, 9e

4. Perioperative Medication Management

β-Blockers (ACC/AHA Recommendations)

"Acutely initiating therapy with β-blockers in at-risk patients who will undergo surgery is no longer recommended." — Morgan and Mikhail's Clinical Anesthesiology, 7e

Statins

Antiplatelet Therapy (Aspirin/DAPT)

• Chronic aspirin for CAD: continue perioperatively in most cases unless bleeding risk outweighs benefit
• DAPT in patients with coronary stents: critical — see stent timing below

Nitrates

• Continue long-acting nitrates perioperatively
• Administer sublingual GTN if angina occurs; have IV nitrates available in high-risk cases
• Avoid hypotension (especially with neuraxial anesthesia)

ACE Inhibitors / ARBs

• Continue in patients with HF or LV dysfunction
• Many anesthesiologists hold on the morning of surgery to prevent refractory intraoperative hypotension — an individualized decision

5. Coronary Revascularization Before Noncardiac Surgery

Timing of Elective Surgery After PCI

"Elective noncardiac surgery should not be performed in patients in whom DAPT will need to be discontinued perioperatively within 30 days after BMS or within 12 months after DES implantation." — Morgan and Mikhail's Clinical Anesthesiology, 7e

6. Intraoperative Management

Anesthetic Goals

• Avoid tachycardia — most important determinant of myocardial O₂ demand; heart rate <80 bpm is the target
• Avoid hypotension — maintain coronary perfusion pressure (MAP ≥65 mmHg)
• Prevent hypertension — avoids increased afterload and wall stress
• Avoid hypothermia — causes shivering and catecholamine surges

Monitoring

• ST-segment monitoring is mandatory: lead II (inferior MI) + lead V5 (anterior MI) detects ~95% of intraoperative ischemia
• Invasive arterial line for high-risk patients undergoing major surgery
• PA catheter / TEE: reserved for high-risk patients with known severe ventricular dysfunction

Anesthetic Technique

• Both regional and general anesthesia are acceptable; neither has been conclusively proven superior
• Neuraxial (epidural/spinal) provides excellent analgesia, blunts sympathetic response — but risk of hypotension must be managed, particularly in tight coronary stenosis
• Avoid high-dose inhalational agents that may cause excessive vasodilation

Treatment of Intraoperative Ischemia

7. Postoperative Management

• Troponin monitoring: measure in patients with signs/symptoms suggesting myocardial injury; routine surveillance in high-risk patients is debated but increasingly practiced (MINS — myocardial injury after noncardiac surgery)
• Continue or restart all cardiac medications (β-blockers, statins, nitrates, antiplatelets) promptly
• Adequate analgesia is critical — inadequate pain control causes catecholamine surges and tachycardia
• Epidural analgesia post-major vascular/thoracic surgery blunts sympathoadrenal response
• Monitor for: MI, arrhythmias, acute HF
• Resume DAPT as soon as surgical hemostasis is secured in patients with coronary stents

8. Special Situations

Unstable Angina / NSTEMI Before Planned Surgery

• Postpone all non-emergency surgery
• Treat as ACS: anticoagulation, antiplatelets, β-blockers, nitrates, statins
• Revascularize if indicated; re-assess timing of surgery after stabilization (DES stent timing applies)

Vasospastic (Prinzmetal's) Angina

• Calcium channel blockers and nitrates are the mainstay — continue perioperatively
• Avoid vasoconstrictors (ergotamine, high-dose vasopressors) that may trigger spasm
• Avoid hyperventilation (causes coronary vasoconstriction)

Combination Therapy Caution

"Patients with ventricular dysfunction may not tolerate the combined negative inotropic effect of a β-blocker and a calcium channel blocker together; an ACE inhibitor or ARB is better tolerated. The additive effect of a β-blocker and calcium channel blocker on the AV node may precipitate heart block in susceptible patients." — Morgan and Mikhail's Clinical Anesthesiology, 7e

Summary

• Morgan and Mikhail's Clinical Anesthesiology, 7e — Chapter 21 (Preoperative Management/CAD)
• Barash, Cullen, and Stoelting's Clinical Anesthesia, 9e — Chapter 23 (Cardiovascular System/Preoperative Assessment)
• Sabiston Textbook of Surgery, 21e — Chapter 19 (Perioperative Cardiac Assessment)
• Harrison's Principles of Internal Medicine, 22e — Perioperative Cardiac Risk Assessment