What is the best approach to assess and mitigate preoperative risk in surgical patients using a preoperative risk calculator, such as the Revised Cardiac Risk Index (RCRI) or American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) risk calculator?

Preoperative Risk Assessment for Surgical Patients

The American College of Surgeons NSQIP Surgical Risk Calculator is the most effective tool for assessing and mitigating preoperative risk in surgical patients, as it provides procedure-specific risk assessment for multiple outcomes including mortality and major cardiac complications. 1

Understanding Risk Assessment Tools

Several validated risk calculators are available for preoperative risk assessment, each with specific strengths:

1. Revised Cardiac Risk Index (RCRI)

• Simple, validated tool with 6 predictors of major cardiac complications 1:
  • High-risk surgery (suprainguinal vascular, intraperitoneal, or intrathoracic)
  • History of ischemic heart disease
  • History of heart failure
  • History of cerebrovascular disease
  • Preoperative insulin treatment for diabetes
  • Preoperative creatinine >2.0 mg/dL
• Risk stratification:
  • 0-1 factors: Low risk (<1% risk of MACE)
  • ≥2 factors: Elevated risk

2. ACS NSQIP Surgical Risk Calculator

• Comprehensive tool based on >1 million operations 1, 2
• Includes 21 patient-specific variables and CPT code for procedure specificity
• Predicts risk for multiple outcomes including:
  • Mortality
  • Major cardiac complications
  • Pneumonia
  • Surgical site infection
  • Length of stay
• Advantages: Procedure-specific risk assessment, more comprehensive than RCRI 1

3. ACS NSQIP MICA Risk Calculator

• Specifically focuses on myocardial infarction and cardiac arrest
• Includes adjusted odds ratios for different surgical sites 1
• Good discrimination for cardiac events, particularly in vascular surgery patients

Algorithmic Approach to Preoperative Risk Assessment

1. Determine surgical risk level:

   • Low risk (<1% risk of MACE)
   • Elevated risk (≥1% risk of MACE) 1

2. For elevated-risk surgery, perform structured assessment:

   • Apply validated risk calculator (RCRI or ACS NSQIP)
   • Assess functional capacity using Duke Activity Status Index (DASI) 1
   • Consider patient's ability to perform >4 METs of activity (e.g., climb 2 flights of stairs) 1

3. Based on risk calculation:

   • Low risk: Proceed to surgery without further cardiac testing 1
   • Elevated risk: Consider additional evaluation or risk mitigation strategies

4. Risk mitigation strategies:

   • Optimize medical management of existing conditions
   • Consider prehabilitation for high-risk patients 3
   • Discuss risks with patients using visual risk calculator outputs

Practical Implementation Tips

• Use the ACS NSQIP calculator (www.riskcalculator.facs.org) for most comprehensive assessment 1
• Supplement with functional capacity assessment using DASI questionnaire 1
• Present risks visually to patients - research shows 90% of patients want to review their ACS calculator report before surgical consent 3
• Consider biomarker testing in selected high-risk patients - addition of biomarkers (hsCRP, H-FABP) can improve predictive accuracy of risk calculators 4

Important Caveats and Pitfalls

1. Risk calculator limitations:

   • NSQIP calculator has not been validated in external populations outside NSQIP 1
   • RCRI may underestimate risk in vascular surgery patients 1
   • Definition of MI varies between calculators, affecting risk estimates 1

2. Patient-specific considerations:

   • High-risk patients often underestimate their surgical risk (3× more likely than low-risk patients) 3
   • Consider GFR <30 mL/min as a better predictor than elevated creatinine alone 5

3. Risk communication:

   • Sharing calculated risks with patients decreases anxiety in 71% of patients 3
   • 70% of patients would consider prehabilitation after seeing their risk profile 3
   • 40% would consider delaying surgery to reduce risk 3

The 2024 AHA/ACC guideline specifically states that while many risk scores exist, data are lacking to support the use of one risk index over another 1. However, the ACS NSQIP Surgical Risk Calculator offers the most comprehensive assessment by incorporating procedure-specific risks and multiple patient factors, making it the preferred option for most clinical scenarios.