Cardiac Risk Calculator
Revised Cardiac Risk Index (RCRI/Lee Index) for estimating perioperative major cardiac event risk.
About this calculator
Before major non-cardiac surgery, clinicians need a quick, reliable way to estimate a patient's risk of a serious cardiac complication -- a heart attack, cardiac arrest, pulmonary edema, or complete heart block -- in the days after the operation. The Revised Cardiac Risk Index, developed by Lee and colleagues in 1999 and often called the Lee Index, remains one of the most widely used tools for this because it needs only six pieces of information available from a standard preoperative history and basic labs: whether the planned surgery is itself high-risk (intraperitoneal, intrathoracic, or suprainguinal vascular surgery), a history of ischemic heart disease, a history of congestive heart failure, a history of cerebrovascular disease (stroke or TIA), insulin-dependent diabetes, and a preoperative creatinine above 2.0 mg/dL indicating reduced kidney function. Each factor present contributes one point to a score from 0 to 6.
This calculator uses the pooled event rates published in the 2017 Canadian Cardiovascular Society perioperative guidelines (Duceppe et al.), a large-scale update covering roughly 792,000 patients across 24 studies, which reported cardiac event rates of 3.9% at a score of 0, 6.0% at a score of 1, 10.1% at a score of 2, and 15.0% at a score of 3 or higher -- notably higher than the original 1999 derivation estimates, reflecting the inclusion of more sensitive troponin-based outcome detection and higher-risk surgical populations in the newer pooled data. The RCRI is deliberately simple, and that simplicity is both its strength (ease of bedside use, wide validation) and its known limitation -- it does not directly capture factors like frailty, exercise tolerance, or the specific severity of heart failure, which is why higher-risk patients identified by RCRI are often referred for further cardiac workup rather than the score alone determining surgical clearance.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
RCRI Score
0
Estimated MACE Risk
3.9%
Figures current as of 2017. Sources: Lee TH, Marcantonio ER, Mangione CM, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation. 1999;100(10):1043-1049., Duceppe E, Parlow J, MacDonald P, et al. Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery. Can J Cardiol. 2017;33(1):17-32.
How to Use This Calculator
- Select Yes or No for each RCRI risk factor: high-risk surgery, ischemic heart disease, CHF, cerebrovascular disease, insulin-dependent diabetes, and creatinine > 2 mg/dL.
- Review RCRI Score, Risk Class, and Estimated MACE Risk (%).
- Class I (0 pts, ~3.9%) and Class II (1 pt, ~6.0%) are lower risk; Class IV (3+ pts, ~15.0%) warrants cardiology consultation.
What each input means
- High-risk surgery
- Intraperitoneal, intrathoracic, or suprainguinal vascular surgery.
- Ischemic heart disease
- History of MI, positive stress test, angina, nitrate use, or Q waves on ECG.
- Congestive heart failure
- History of CHF, pulmonary edema, PND, S3 gallop, or bilateral rales.
- Cerebrovascular disease
- History of stroke or TIA.
- Insulin-dependent diabetes
- Diabetes mellitus requiring insulin therapy.
- Creatinine > 2 mg/dL
- Preoperative serum creatinine > 2.0 mg/dL.
What each result means
- RCRI Score
- Total score 0-6. Each risk factor adds 1 point.
- Risk Class
- Class I (0 pts), II (1 pt), III (2 pts), IV (3+ pts).
- Estimated MACE Risk
- Estimated risk of major cardiac event (MI, pulmonary edema, VF/cardiac arrest, complete heart block).
- Risk Level
- 1 = Low, 2 = Moderate, 3 = Elevated, 4 = High.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersHigh-risk surgery = 0, Ischemic heart disease = 0, Congestive heart failure = 0, Cerebrovascular disease = 0 = 6 input(s) provided
- Calculate RCRI ScoreRCRI Score0 = 0
- Calculate Estimated MACE Risk3.9 = 3.9
- Calculate Risk Class1 = 1
- Calculate Risk Level1 = 1
Figures and sources
- Revised Cardiac Risk Index (Lee Index) for perioperative cardiac risk (1999) — Lee TH, Marcantonio ER, Mangione CM, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation. 1999;100(10):1043-1049.
- 2017 Canadian Cardiovascular Society perioperative guideline (pooled RCRI event rates) (2017) — Duceppe E, Parlow J, MacDonald P, et al. Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery. Can J Cardiol. 2017;33(1):17-32.
Engine last updated . Checked against 3 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why did the estimated risk percentages for each RCRI class change from the original 1999 study?
The pooled event rates this calculator uses come from the 2017 Canadian Cardiovascular Society guideline update, a systematic review of roughly 792,000 patients across 24 studies, rather than Lee's original single-cohort derivation. The newer, larger dataset reported higher cardiac event rates at every RCRI class -- partly because modern studies more sensitively detect perioperative myocardial injury using troponin testing, which the original 1999 study did not have available, and partly because the pooled population includes a broader mix of surgical risk than the original derivation cohort.
Does an RCRI score of 0 mean a patient has no cardiac risk at all for surgery?
No -- a score of 0 corresponds to the lowest risk category in this tool, with a pooled estimated event rate of roughly 3.9%, not zero risk. The RCRI identifies six specific, well-established risk factors, but it does not capture every possible cardiac risk contributor (such as frailty, functional capacity, or valvular disease severity), so a low RCRI score should be read as "low relative risk on this specific tool," not as a guarantee of an uncomplicated perioperative course.
Why does creatinine above 2.0 mg/dL count as a cardiac risk factor rather than a kidney-specific one?
Significant renal impairment is strongly associated with underlying cardiovascular disease and independently predicts perioperative cardiac complications, likely reflecting shared risk factors (diabetes, hypertension, atherosclerosis) as well as fluid and electrolyte instability that can stress the heart during and after surgery. Lee's original analysis found it to be one of the six strongest independent predictors of perioperative cardiac events, which is why it is included in the index alongside more obviously cardiac-specific factors like ischemic heart disease and heart failure.
What typically happens clinically when a patient scores in the highest RCRI risk class?
A score of 3 or more points, with a pooled estimated cardiac event rate around 15%, generally prompts closer preoperative evaluation -- which may include further cardiac testing, optimization of heart failure or ischemic heart disease management before surgery, and a more detailed discussion between the surgical and anesthesia teams about perioperative monitoring. The RCRI itself does not dictate a specific intervention; it is a triage tool that flags who benefits from that closer look.
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