Tools for Surgical Risk Assessment
The most widely validated and recommended tools for assessing surgical risk include the Revised Cardiac Risk Index (RCRI), American Society of Anesthesiologists Physical Status Classification (ASA-PS), and specialized calculators like the National Surgical Quality Improvement Program (NSQIP) risk calculator. 1, 2, 3
Cardiac Risk Assessment Tools
The Revised Cardiac Risk Index (RCRI) is the most extensively validated tool for predicting major adverse cardiac events (MACE) post-operatively, with six independent predictors: ischemic heart disease, heart failure, cerebrovascular disease, insulin-dependent diabetes, renal dysfunction, and high-risk surgery 1, 2, 3
RCRI stratifies patients into risk categories: 0 factors (low risk, <1% MACE), 1 factor (low-moderate risk), 2 factors (moderate risk), and ≥3 factors (high risk) 2, 4, 3
The American College of Surgeons NSQIP Myocardial Infarction and Cardiac Arrest (MICA) risk calculator provides potentially superior predictive discrimination in some populations 3
The American University of Beirut (AUB) HAS2 cardiovascular risk index is a newer tool that stratifies patients into low (score 0-1), intermediate (score 2-3), and high risk (score >3) based on 6 clinical elements 4, 3
Nutritional Risk Assessment Tools
The Nutritional Risk Screening (NRS-2002) is recommended by the European Society for Clinical Nutrition and Metabolism (ESPEN) and validated for both elective surgical and critically ill patients 1
Other validated nutritional screening tools include:
The Global Leadership Initiative on Malnutrition developed a 2-step approach for diagnosing malnutrition that has been validated as both sensitive and specific 1
General Surgical Risk Tools
The American Society of Anesthesiologists Physical Status Classification (ASA-PS) is a reliable independent predictor of medical complications and mortality following surgery, with increasing levels (1-5) corresponding to significantly higher risks 5, 6
The Surgical Outcome Risk Tool (SORT) comprises six variables: ASA-PS grade, urgency of surgery, high-risk surgical specialty, surgical severity, cancer, and age ≥65 years, demonstrating better discrimination than ASA-PS alone 7
Combining ASA-PS with surgeon risk estimates has shown improved prediction of postoperative complications, with model discrimination comparable to traditional clinical data-based models 5
Functional Capacity Assessment
Functional capacity assessment is a reliable predictor of perioperative and long-term cardiac events 1
The Duke Activity Status Index (DASI) is recommended to be combined with risk scores for better stratification 3
Poor functional capacity (inability to achieve 4 METs) indicates increased risk of perioperative adverse cardiovascular events 3
Biomarker Assessment
B-type natriuretic peptide (BNP) levels can provide additional risk stratification beyond standard risk scores 3
The American Heart Association suggests that biomarker assessment (BNP/NT-proBNP) may be reasonable for additional risk stratification (Class 2a recommendation) 2
Practical Application
For low-risk patients (RCRI 0-1), proceed with standard monitoring during surgery 1, 2, 3
For high-risk patients (RCRI ≥3), implement comprehensive cardiac monitoring and consider surveillance for myocardial injury after noncardiac surgery 3
Combining multiple assessment tools (e.g., RCRI with functional capacity assessment) provides more comprehensive risk stratification than any single tool alone 1, 2, 3
Limitations and Considerations
No single risk score has been definitively proven superior to others for all surgical populations 3
Risk scores have poorer discrimination in patients undergoing vascular surgery, likely due to underestimation of cardiac risk 3
ASA-PS on its own is not a complete predictor of operative risk, which also depends on procedural factors and provider expertise 8
Patients with ASA grade of 3 or 4 benefit from preoperative consultation with a senior anesthesiologist to optimize their condition 8