What is the RCRI?
The Revised Cardiac Risk Index (RCRI), also known as the Lee Index, was published by Thomas H. Lee and colleagues in 1999 in the journal Circulation. It is the most widely used and validated tool for estimating the risk of major perioperative cardiac complications in patients undergoing non-cardiac surgery.
The RCRI simplified the original Goldman Cardiac Risk Index (1977) from 9 variables to just 6 easily assessed clinical criteria. Its simplicity and reasonable predictive accuracy have made it the standard initial assessment tool recommended by the ACC/AHA guidelines for perioperative cardiovascular evaluation.
Scoring System
Each of the six criteria contributes exactly 1 point. The total score ranges from 0 (no risk factors present) to 6 (all risk factors present).
Score Interpretation
| RCRI Score | Lee Class | Estimated Risk of Major Cardiac Event | Risk Category |
|---|---|---|---|
| 0 | I | 3.9% | Low |
| 1 | II | 6.0% | Low-Moderate |
| 2 | III | 10.1% | Moderate |
| ≥3 | IV | 15% (or higher) | High |
Major cardiac events include: myocardial infarction, pulmonary edema, ventricular fibrillation or primary cardiac arrest, and complete heart block.
Risk Stratification Diagram
The Six Criteria Explained
1. High-Risk Surgery
This criterion applies to intraperitoneal (abdominal), intrathoracic (chest), or suprainguinal vascular procedures. These surgeries are associated with greater hemodynamic stress, fluid shifts, and longer operative times. Low-risk surgeries (endoscopic, superficial, cataract, breast) do not meet this criterion.
2. Ischemic Heart Disease
Includes any history of myocardial infarction, pathological Q waves on ECG, positive stress test, current angina with nitrate use, or prior coronary revascularization (CABG or PCI). Stable coronary artery disease that has been appropriately revascularized may carry less risk than suggested by this simple criterion.
3. Congestive Heart Failure
History of CHF or current signs/symptoms including paroxysmal nocturnal dyspnea, bilateral rales or crackles, S3 gallop, or chest X-ray showing pulmonary vascular redistribution. Both systolic (HFrEF) and diastolic (HFpEF) heart failure count.
4. Cerebrovascular Disease
History of stroke (ischemic or hemorrhagic) or transient ischemic attack (TIA). This criterion reflects underlying atherosclerotic burden that often coexists with coronary artery disease.
5. Insulin-Dependent Diabetes
Only diabetes treated with insulin meets this criterion. Diabetes managed with oral agents alone or diet does not qualify. Insulin-dependent diabetes is a marker for more advanced disease with greater vascular complications.
6. Preoperative Renal Insufficiency
Serum creatinine greater than 2.0 mg/dL (>177 micromol/L). Renal insufficiency is both a marker for vascular disease and an independent predictor of perioperative cardiac complications due to volume overload, electrolyte abnormalities, and impaired drug clearance.
Preoperative Evaluation
The RCRI is typically used as part of a stepwise approach to preoperative cardiac risk assessment:
- Assess urgency: Emergency surgery proceeds regardless of cardiac risk
- Screen for active cardiac conditions: Unstable angina, decompensated heart failure, severe arrhythmias, and severe valvular disease require evaluation before elective surgery
- Apply RCRI: Calculate the score to estimate perioperative risk
- Assess functional capacity: Patients who can perform ≥4 METs of activity (climb 2 flights of stairs) generally have adequate cardiac reserve
- Consider further testing: Noninvasive cardiac testing may be indicated for high-risk patients with poor functional capacity undergoing high-risk surgery
RCRI vs. Gupta Calculator
| Feature | RCRI (Lee Index) | Gupta Perioperative Calculator |
|---|---|---|
| Year Published | 1999 | 2011 |
| Variables | 6 (yes/no) | 5 (continuous + categorical) |
| Predicts | Major cardiac events | Myocardial infarction or cardiac arrest |
| Derivation Cohort | 4,315 patients | 211,410 patients (NSQIP) |
| Ease of Use | Very simple (mental math) | Requires calculator |
| ASA Classification | Not included | Included |
| Surgery Type | Binary (high-risk yes/no) | Specific procedure codes |
| Best For | Quick bedside assessment | More precise risk estimation |
Worked Example
A 68-year-old patient scheduled for elective colectomy (intraperitoneal surgery) with a history of myocardial infarction 3 years ago and insulin-dependent diabetes:
Ischemic heart disease: +1
Insulin-dependent diabetes: +1
CHF: 0 | CVD: 0 | Cr >2: 0
RCRI Score = 3 → Lee Class IV → 15% risk
With an RCRI score of 3, this patient is at high risk for major cardiac events. Further evaluation including functional capacity assessment and potentially noninvasive cardiac testing would be indicated before proceeding with elective surgery.
Frequently Asked Questions
Is the RCRI valid for all types of surgery?
The RCRI was derived and validated for non-cardiac surgery only. It should not be applied to cardiac surgery (CABG, valve replacement), which has its own risk scoring systems (STS score, EuroSCORE). It is also less well-validated for very low-risk procedures (cataract surgery, endoscopy) where cardiac events are extremely rare.
Does a score of 0 mean the surgery is risk-free?
No. A score of 0 indicates the lowest risk category (Lee Class I) with an estimated 3.9% risk of major cardiac events. This is not zero risk. The baseline risk accounts for age, anesthesia effects, and other factors not captured by the six criteria.
Should I get additional cardiac testing if my RCRI is high?
Not necessarily. The ACC/AHA guidelines recommend a stepwise approach. Additional testing is most useful when the results would change management. If surgery is urgent, if the patient has excellent functional capacity (≥4 METs), or if the results would not alter the surgical plan, further testing may not be indicated despite a high RCRI score.
How accurate is the RCRI?
The RCRI has been validated in numerous studies with a C-statistic (area under the ROC curve) of approximately 0.75, which indicates moderate discriminatory ability. It tends to underestimate risk in very high-risk populations (vascular surgery patients) and overestimate risk in low-risk populations. For vascular surgery specifically, the Gupta calculator may provide better discrimination.