What is the recommended approach for cardiopulmonary evaluation and risk stratification in a surgical patient with potential cardiopulmonary risk factors?

Cardiopulmonary Evaluation and Risk Stratification in Surgical Patients

Base your preoperative cardiopulmonary evaluation on clinical history, physical examination, and functional capacity assessment—not routine testing—then selectively order tests only when results will change perioperative management. 1

Initial Risk Assessment Framework

Step 1: Clinical History and Physical Examination

The cornerstone of risk stratification begins with targeted assessment of specific risk factors rather than blanket testing 1, 2:

• Cardiovascular symptoms: Assess for chest pain, dyspnea, orthopnea, palpitations, syncope, or edema 1
• Cardiac risk factors: Document history of coronary disease, heart failure, cerebrovascular disease, diabetes mellitus, and renal insufficiency 1, 3
• Pulmonary risk factors: Identify COPD (OR 1.79), age >60 years (OR 2.09-3.04), ASA class ≥II (OR 4.87), functional dependence (OR 1.65-2.51), congestive heart failure (OR 2.93), albumin <35 g/L, and current smoking (OR 1.26) 4
• Functional capacity: Determine if patient can achieve ≥4 METs (climb 2 flights of stairs, walk up a hill, or perform heavy housework) 1

Step 2: Surgical Risk Categorization

Classify the planned procedure 1:

• Low-risk (<1% cardiac event rate): Endoscopic, superficial, cataract, breast surgery
• Intermediate-risk (1-5%): Intraperitoneal, intrathoracic, carotid, orthopedic, prostate surgery
• High-risk (>5%): Aortic/major vascular surgery, prolonged procedures >3 hours (OR 2.14), emergency surgery (OR 4.47) 1, 4

Cardiovascular Testing Algorithm

Electrocardiography

Order ECG for 1:

• High-risk surgery (all patients)
• Intermediate-risk surgery with ≥1 cardiac risk factor
• Known cardiovascular disease, arrhythmias, or structural heart disease

Do NOT order ECG for 1:

• Low-risk surgery in asymptomatic patients
• Routine screening without clinical indication

Stress Testing (Exercise or Pharmacological)

Consider noninvasive stress testing ONLY when 1:

• Patient has elevated surgical risk AND
• Poor functional capacity (<4 METs) AND
• Results will change management (e.g., guide medical optimization or revascularization decisions)

Do NOT perform stress testing for 1:

• Low-risk surgery (regardless of patient factors)
• Patients with excellent functional capacity (>10 METs)—it is reasonable to forgo testing even with elevated surgical risk 1
• Routine screening when results won't alter management 1

Important caveat: Prophylactic coronary revascularization before noncardiac surgery has NOT been shown to reduce perioperative risk, so stress testing should guide medical therapy (beta-blockers, statins) rather than trigger automatic catheterization 1

Echocardiography

Assess left ventricular function when 1:

• Clinical heart failure with unknown ejection fraction
• Dyspnea of unclear etiology
• Worsening heart failure symptoms

Do NOT routinely assess LV function 1:

• Stable, compensated heart failure with known recent LVEF
• Absence of clinical heart failure symptoms

The relationship between reduced LVEF and complications is strongest when LVEF <35%, but adds only modest predictive value beyond clinical factors 1

Cardiopulmonary Exercise Testing (CPET)

May consider for 1:

• Elevated-risk procedures when functional capacity is unknown or uncertain
• Major abdominal, vascular, or thoracic surgery candidates

An anaerobic threshold <10-11 mL O₂/kg/min predicts increased cardiovascular complications and mortality 1

Cardiac Risk Scoring

Use the Thoracic Revised Cardiac Risk Index (ThRCRI) rather than standard RCRI for thoracic surgery patients 1:

• ThRCRI >1.5: Refer for cardiology consultation
• Any cardiac condition requiring medication: Refer for evaluation
• Newly suspected cardiac condition: Refer for workup
• Limited exercise tolerance (cannot climb 2 flights of stairs): Refer for assessment 1

Pulmonary Testing Algorithm

Routine Testing NOT Recommended

Do NOT routinely order 4, 5:

• Preoperative spirometry for risk prediction
• Chest radiography for risk prediction
• These tests do not reduce complications and should only be obtained when results will change management 1

When to Obtain Chest X-Ray

Order chest radiography only for 1:

• Patients at risk of postoperative pulmonary complications IF results would change perioperative management
• Acute cardiopulmonary symptoms requiring evaluation

Albumin Measurement

Measure serum albumin in 4:

• All patients clinically suspected of hypoalbuminemia
• Patients with ≥1 risk factor for postoperative pulmonary complications
• Low albumin (<35 g/L) is one of the most powerful predictors of pulmonary complications 4

Special Population Considerations

Severely Obese Patients

Assessment approach 1:

• Functional exercise testing is preferred when feasible
• If unable to exercise due to weight/orthopedic issues, use pharmacological stress testing
• Consider transesophageal dobutamine stress echocardiography for poor acoustic windows
• Evaluate for obesity cardiomyopathy, diabetic cardiomyopathy, or hibernating myocardium 1

Elderly Patients (>80 Years)

Do NOT dismiss surgery based solely on age 1:

• Fully evaluate cardiopulmonary fitness without age prejudice
• Consider tumor stage, life expectancy, performance status, and comorbidities
• Careful patient selection with thorough preoperative evaluation is mandatory 1

Patients with Congenital Heart Disease

Refer to specialized centers 3:

• Prior Fontan procedure
• Severe pulmonary arterial hypertension
• Cyanotic congenital heart disease
• Complex congenital heart disease
• Left ventricular assist devices

Laboratory Testing Principles

Order selectively based on clinical indication 1:

• Electrolytes/creatinine: Chronic disease, medications predisposing to abnormalities
• Glucose: High risk of undiagnosed diabetes; HbA1c only if results change management
• Complete blood count: Diseases increasing anemia risk, anticipated significant blood loss
• Coagulation studies: Bleeding history, conditions predisposing to bleeding, anticoagulant use
• Urinalysis: Invasive urologic procedures, foreign material implantation

Critical Pitfalls to Avoid

• Do NOT order routine preoperative testing batteries—this increases costs, delays surgery, and rarely changes management 1
• Do NOT perform stress testing or angiography unless results will change management—coronary revascularization specifically for surgery provides limited benefit 1
• Do NOT use right-heart catheterization solely for reducing pulmonary complication risk 4
• Do NOT rely on prediction scores alone—assess all patient-related risk factors individually 4
• Avoid aggressive cardiac interventions specifically for surgery—reserve these only for patients who need them irrespective of the surgical procedure 1

Postoperative Monitoring for High-Risk Patients

Obtain ECGs 3:

• At baseline
• Immediately after surgery
• On postoperative days 1 and 2

Monitor cardiac biomarkers in 3:

• High-risk patients
• Those with clinical, ECG, or hemodynamic evidence of cardiovascular dysfunction