What scores are used to evaluate surgical risk in patients with comorbidities like coronary artery disease, diabetes, or hypertension?

Surgical Risk Assessment Scores for Patients with Comorbidities

Use the Revised Cardiac Risk Index (RCRI) as your initial risk stratification tool for all patients undergoing non-cardiac surgery, then enhance prediction with the Duke Activity Status Index (DASI) for functional capacity assessment and consider the ACS NSQIP Surgical Risk Calculator for comprehensive risk estimation. 1, 2

Primary Risk Stratification: RCRI

The RCRI assigns 1 point for each of 6 risk factors present: 1, 2

• History of ischemic heart disease (including coronary artery disease)
• History of congestive heart failure
• History of cerebrovascular disease
• Preoperative insulin-dependent diabetes mellitus
• Preoperative serum creatinine >2.0 mg/dL or chronic kidney disease
• High-risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular procedures)

Risk interpretation: 2

• RCRI 0-1: Low risk (<1% MACE rate) - proceed directly to surgery without additional cardiac testing
• RCRI 2: Moderate risk - assess functional capacity; additional testing only if functional capacity is poor or unknown AND results would change management
• RCRI ≥3: High risk (14.4% complication rate) - comprehensive cardiac monitoring, functional capacity assessment, and consider pharmacological stress testing if it would alter management

Functional Capacity Assessment: DASI

The Duke Activity Status Index should be used for all patients with RCRI ≥1 undergoing elevated-risk surgery, as it significantly increases predictive power when added to RCRI. 1, 2

The DASI is a 12-item questionnaire scoring 0-58.2 points based on ability to perform daily activities: 1

• DASI >34 or ≥4 METs: Good functional capacity - patients can proceed to surgery even with elevated RCRI scores
• DASI ≤34 or <4 METs: Poor functional capacity - identifies patients at 1.63 times higher rate of death, MI, acute heart failure, or life-threatening arrhythmias; consider pharmacological stress testing if results would change management

Key threshold activity: Ability to climb 2 flights of stairs indicates >4 METs and adequate functional capacity. 1

Enhanced Risk Prediction: ACS NSQIP Surgical Risk Calculator

For patients with multiple comorbidities (hypertension, diabetes, coronary artery disease), use the ACS NSQIP Surgical Risk Calculator as it provides superior predictive accuracy with procedure-specific risk estimates. 2

This calculator incorporates 21 patient-specific variables including: 2

• Age, sex, BMI
• Dyspnea status
• Previous MI
• Functional status
• Specific comorbidities: diabetes, hypertension, cardiovascular disease
• Specific CPT codes for procedure-specific assessment

The calculator provides percentage risk for 8 different outcomes including MACE and mortality, with better discrimination (median delta c-statistic 0.11 higher than RCRI). 2

Biomarker Enhancement for High-Risk Patients

Measure NT-proBNP and/or troponin preoperatively for patients with RCRI ≥2 to enhance risk prediction. 2

• NT-proBNP and troponin combination improves discrimination with median delta c-statistic of 0.12
• BNP alone shows median delta c-statistic 0.15 higher than RCRI for MACE prediction
• Measure troponin at 48-72 hours postoperatively in high-risk patients (RCRI ≥2) 2

Special Population Considerations

For thoracic surgery patients, use the Thoracic Revised Cardiac Risk Index (ThRCRI) instead of standard RCRI, as it provides more accurate risk assessment with weighted factors specific to thoracic procedures. 2

For vascular surgery patients, the NSQIP MICA (Myocardial Infarction or Cardiac Arrest) calculator may outperform RCRI, particularly in predicting cardiac arrest and MI. 2

For severely obese patients (BMI ≥40 kg/m²), consider the obesity surgery mortality score for gastric bypass procedures, and recognize that age, male sex, cardiorespiratory fitness, electrolyte disorders, and heart failure are independent predictors of surgical mortality. 1

Critical Pitfalls to Avoid

Do not perform stress testing or coronary angiography unless abnormal results would lead to coronary revascularization, medication changes, or surgical cancellation. 1, 2 Several studies have been unable to document benefits of coronary revascularization before noncardiac surgery. 1

Do not use the American Society of Anesthesiology Physical Status Classification as the primary risk tool due to poor inter-rater reliability. 2

Do not automatically cancel surgery for blood pressure 160/95 mmHg, as this level does not mandate postponement and each postponed month adds a 1% relative increase in cardiovascular risk due to patient aging. 3

For patients with diabetes, ensure HbA1c is optimally <8% before elective surgery, hold metformin on the day of surgery, and discontinue SGLT2 inhibitors 3-4 days before surgery to prevent euglycemic diabetic ketoacidosis. 3

For patients with hypertension, hold ACE inhibitors/ARBs 24 hours before surgery to reduce intraoperative hypotension, but continue beta blockers and clonidine to avoid rebound hypertension. 3