Residency · Residency · Anesthesiology
Preoperative Cardiac Risk Assessment: Guidelines in Practice
Introduction
Cardiovascular complications remain the leading cause of perioperative morbidity and mortality in noncardiac surgery. The anesthesiologist plays a central role in preoperative cardiac risk assessment, integrating patient history, functional capacity, surgical risk, and evidence-based guidelines to determine whether further evaluation, optimization, or modification of the surgical plan is warranted. The 2014 ACC/AHA guideline (updated 2024) and the 2022 ESC/ESA guideline provide the primary frameworks.
Stepwise Approach to Cardiac Risk Assessment
Step 1: Is the Surgery Emergent?
If the surgery is emergent, it should proceed with appropriate monitoring and perioperative risk mitigation. Further cardiac testing should not delay emergent intervention. Clinical risk stratification and perioperative beta-blockade or monitoring can be applied simultaneously.
Step 2: Does the Patient Have an Acute Coronary Syndrome (ACS)?
Unstable angina, NSTEMI, or STEMI within the past 60 days are active cardiac conditions that mandate evaluation and treatment before elective surgery. Other active conditions requiring evaluation include decompensated heart failure, significant arrhythmias (high-grade AV block, symptomatic ventricular arrhythmias, supraventricular tachycardia with uncontrolled rate), and severe valvular disease (symptomatic aortic stenosis, symptomatic mitral stenosis).
Step 3: Estimate Surgical Risk
| Risk Category | Cardiac Risk (<1% / 1-5% / >5%) | Examples |
|---|---|---|
| Low risk | <1% | Endoscopy, superficial procedures, cataract surgery, breast biopsy |
| Intermediate risk | 1-5% | Intraperitoneal, intrathoracic, orthopedic, head and neck, prostate |
| High risk | >5% | Aortic/major vascular, peripheral vascular surgery, prolonged procedures with large fluid shifts |
Step 4: Assess Functional Capacity
Functional capacity is measured in metabolic equivalents (METs). A capacity of 4 METs or greater without symptoms is generally adequate for most noncardiac surgery, and the patient can proceed without further testing. Four METs corresponds to activities such as climbing one flight of stairs, walking uphill, or performing heavy housework. When functional capacity is less than 4 METs or unknown, the number of clinical risk factors and surgical risk are considered to determine whether further testing is indicated. The Duke Activity Status Index (DASI) is a validated questionnaire for objective functional capacity assessment.
Step 5: Apply the Revised Cardiac Risk Index (RCRI)
The RCRI (Lee Index) uses six independent predictors of major cardiac events: high-risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular), history of ischemic heart disease, history of heart failure, history of cerebrovascular disease, diabetes mellitus requiring insulin, and preoperative creatinine greater than 2.0 mg/dL.
| RCRI Score | Estimated Cardiac Risk |
|---|---|
| 0 | 3.9% |
| 1 | 6.0% |
| 2 | 10.1% |
| >=3 | 15% |
Preoperative Cardiac Testing
When to Order (and When Not To)
A resting ECG is reasonable for patients with known cardiovascular disease, significant risk factors, or symptoms undergoing intermediate-to-high-risk surgery, but it is not indicated for asymptomatic patients undergoing low-risk procedures. Resting echocardiography is indicated for new or worsening dyspnea of unknown origin, known heart failure with a change in clinical status, or suspected significant valvular disease, but is not recommended as routine preoperative screening. Stress testing (exercise or pharmacologic) should be considered only when results will change management and the patient has elevated risk (RCRI of 2 or more) with poor or unknown functional capacity undergoing high-risk surgery; routine stress testing rarely changes outcomes. Coronary angiography is pursued only if indicated independently of surgery, such as for an acute coronary syndrome or a positive stress test with high-risk features.
Key Principle
A test should not be ordered unless the result will change perioperative management. Preoperative revascularization has not been shown to improve outcomes compared to optimal medical therapy in stable coronary artery disease, as demonstrated by the CARP trial and DECREASE-V.
Biomarkers
BNP and NT-proBNP are useful preoperative biomarkers, with elevated levels (BNP greater than 92 pg/mL, NT-proBNP greater than 300 pg/mL) independently predicting postoperative cardiac events and mortality. The ESC/ESA guidelines recommend preoperative natriuretic peptide measurement for high-risk patients. Preoperative troponin elevation indicates myocardial injury, and postoperative troponin surveillance may be considered for high-risk patients. The VISION study demonstrated an association between postoperative troponin elevation and 30-day mortality.
Perioperative Medical Therapy
Beta-Blockers
Beta-blockers should be continued in patients already taking them chronically, as abrupt withdrawal increases cardiac risk. High-dose beta-blockers should not be started on the day of surgery; the POISE trial demonstrated that while perioperative metoprolol reduced myocardial infarction, it increased stroke and overall mortality. If initiating beta-blocker therapy perioperatively, it should be started days to weeks before surgery, titrated to a heart rate of 60 to 80 bpm, and hypotension should be avoided.
Statins
Statins should be continued perioperatively because abrupt discontinuation may increase the risk of plaque instability. Initiating statins preoperatively should be considered in vascular surgery patients, where evidence supports benefit.
Antiplatelet Agents
Detailed management is covered in the dedicated lecture on perioperative anticoagulant and antiplatelet management (Lecture 71). Aspirin should be continued in patients with coronary stents within 6 weeks of bare-metal stent placement or 6 months of drug-eluting stent placement; otherwise, the benefits of continuation are debated.
ACE Inhibitors/ARBs
These agents are associated with intraoperative hypotension refractory to vasopressors. It is reasonable to hold them on the morning of surgery for patients undergoing procedures with expected hemodynamic shifts, with resumption postoperatively when the patient is euvolemic. They should be continued in heart failure patients who are volume-optimized.
Anticoagulants
Bridging and management are covered in Lecture 71.
Coronary Stents and Surgery Timing
| Stent Type | Minimum Delay for Elective Surgery | DAPT Requirement |
|---|---|---|
| Balloon angioplasty | 2 weeks | Aspirin |
| Bare-metal stent (BMS) | 30 days (minimum); 3 months ideal | DAPT 1 month minimum |
| Drug-eluting stent (DES) | 6 months (minimum); 12 months ideal | DAPT 6-12 months |
Premature discontinuation of dual antiplatelet therapy (DAPT) is the strongest predictor of stent thrombosis, which carries a mortality of 20 to 40%. If surgery cannot be delayed, aspirin should be continued and P2Y12 inhibitor management should be discussed with cardiology.
Special Considerations
Aortic Stenosis
Severe symptomatic aortic stenosis (valve area less than 1.0 cm2, mean gradient greater than 40 mmHg) carries the highest perioperative cardiac risk among valvular lesions. Elective noncardiac surgery should be deferred for valve replacement or TAVR. If urgent surgery is needed, management includes invasive monitoring, avoidance of hypotension (maintaining SVR), maintenance of sinus rhythm, and avoidance of tachycardia.
Heart Failure
Decompensated heart failure is an active cardiac condition requiring optimization before elective surgery. Optimized, stable HFrEF patients can proceed with appropriate monitoring. BNP and NT-proBNP trending is useful for assessing optimization.
Pulmonary Hypertension
A mean pulmonary artery pressure greater than 25 mmHg increases perioperative risk significantly. Hypoxia, hypercarbia, and acidosis must be avoided because all increase pulmonary vascular resistance. Pulmonary vasodilators should be continued perioperatively, and a pulmonary hypertension specialist should be consulted.
Key Clinical Pearls
Functional capacity is the most powerful clinical predictor of perioperative cardiac risk; a patient who can climb two flights of stairs without symptoms rarely needs further testing. The RCRI is a useful screening tool but underestimates risk in vascular surgery patients, where additional biomarkers such as BNP and NT-proBNP add value. Preoperative revascularization does not improve outcomes in stable coronary artery disease, and optimal medical therapy should be pursued instead, as shown by the CARP trial. Beta-blockers and statins should never be abruptly discontinued perioperatively. The most common perioperative cardiac event is myocardial injury after noncardiac surgery (MINS), which is often asymptomatic and detected only by troponin surveillance.
References
- Fleisher LA, Fleischmann KE, Auerbach AD, et al. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery. Circulation. 2014;130(24):e278-e333.
- Halvorsen S, Mehilli J, Cassese S, et al. 2022 ESC Guidelines on cardiovascular assessment and management of patients undergoing non-cardiac surgery. Eur Heart J. 2022;43(39):3826-3924.
- Devereaux PJ, Sessler DI. Cardiac complications in patients undergoing major noncardiac surgery. N Engl J Med. 2015;373(23):2258-2269.
- McFalls EO, Ward HB, Moritz TE, et al. Coronary-artery revascularization before elective major vascular surgery (CARP trial). N Engl J Med. 2004;351(27):2795-2804.