RCRI calculator

The Revised Cardiac Risk Index, often called Lee's index after the 1999 Circulation derivation, is a six-item preoperative score for major cardiac complications after noncardiac surgery. This calculator accepts six clinical flags—high-risk surgery, ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, and a creatinine above 2.0 mg/dL—and returns the integer score from zero through six, risk class I through IV, and the published Lee major-cardiac-event percentage.

What the Revised Cardiac Risk Index measures and how Lee's six points work

The Revised Cardiac Risk Index is a bedside additive rule that Lee and colleagues derived and then prospectively validated for adults undergoing elective major noncardiac surgery, and it remains one of the most taught preoperative cardiac scores in anesthesia, cardiology, and surgical clerkships. Each of six independent predictors contributes exactly one point when present and zero when absent. The first factor is high-risk surgery, meaning intraperitoneal, intrathoracic, or suprainguinal vascular procedures rather than low-risk ambulatory work.

The second is a history of ischemic heart disease, including prior myocardial infarction, a positive exercise test, current ischemic chest pain, nitrate therapy, or pathologic Q waves. The third is a history of congestive heart failure, including pulmonary edema, paroxysmal nocturnal dyspnea, bilateral rales, an S3 gallop, or a chest radiograph with pulmonary vascular redistribution. The fourth is cerebrovascular disease, meaning a prior transient ischemic attack or stroke.

The fifth is diabetes mellitus treated with insulin in the preoperative period. The sixth is a preoperative serum creatinine greater than 2.0 milligrams per decilitre, equivalent to 177 micromoles per litre. The score is the count of those six flags, so it ranges from zero to six.

Class I is zero points, class II is one point, class III is two points, and class IV is three or more points. In the original derivation cohort the rates of major cardiac complications—myocardial infarction, pulmonary edema, ventricular fibrillation or primary cardiac arrest, and complete heart block—were 0.4 percent, 0.9 percent, 6.6 percent, and 11 percent respectively.

How to read risk classes, where the calculator belongs, and what it does not decide

Risk class I is low risk, with a Lee derivation major-cardiac-event rate of 0.4 percent, and is the usual teaching band when none of the six factors is present. Class II is low-intermediate risk at 0.9 percent with a single factor. Class III is intermediate risk at 6.6 percent with two factors, which is the band where many teaching discussions start to mention further testing or closer perioperative surveillance rather than routine discharge planning.

Class IV is high risk at 11 percent once three or more factors are present; scores of three, four, five, and six share that class rather than inventing extra bands that the original paper did not publish. Those percentages are historical cohort figures from 1999, not a personal prognosis, and they do not replace functional-capacity assessment, the inherent risk of the planned procedure beyond the high-risk flag, natriuretic peptides, stress testing, or a clinician's view of comorbidities this table never captures.

Use the calculator for education, exam keys, research coding of preoperative rows, and product prototypes that need a deterministic RCRI step before handing off to licensed systems. Neighbouring tools such as the Gupta myocardial infarction or cardiac arrest calculator, NSQIP, or an eGFR engine answer different search intents and should keep their own landings rather than being overloaded here.