The Revised Cardiac Risk Index (RCRI) calculator assesses perioperative cardiac risks by taking into account six specific risk factors associated with the patient. Each factor corresponds to a condition or characteristic, and if the patient exhibits that factor, it scores 1 point. The total score, ranging from 0 to 6, represents the overall cardiac risk.

The six risk factors analyzed are as follows:
1. High-risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular surgery)
2. History of ischemic heart disease (including myocardial infarction, positive exercise test, ECG with pathological Q waves, current ischemic chest pain, or use of nitrate)
3. History of congestive heart failure (with manifestations such as pulmonary edema, bilateral rales, S3 gallop, paroxysmal nocturnal dyspnea, or pulmonary vascular redistribution on chest X-ray)
4. History of cerebrovascular disease (transient ischemic attack or stroke)
5. Use of insulin for diabetes
6. Preoperative creatinine level above 2 mg/dL or 178 mcmol/L

A boolean input for each risk factor determines its presence, scoring 1 point if true and 0 if false. The sum of these points results in the total score.

Based on the computed score, the calculator provides an interpretation reflecting the patient's estimated risk of experiencing a major cardiac event (MI, cardiac arrest, or mortality) within 30 days post-surgery:

- Score of 0: Risk is 3.9%
- Score of 1: Risk is 6.0%
- Score of 2: Risk is 10.1%
- Score of 3 or more: Risk is 15.0%

The calculator simplifies the complex assessment of cardiac perioperative risks into a quantifiable measure, guiding healthcare providers in evaluating and mitigating potential cardiac complications in surgical patients. Here is the summary of how scores are interpreted in relation to risk percentages:

| Score | Risk Interpretation                                  |
|-------|------------------------------------------------------|
| 0     | Risk of 30-day MI, cardiac arrest, or mortality is 3.9% |
| 1     | Risk of 30-day MI, cardiac arrest, or mortality is 6.0% |
| 2     | Risk of 30-day MI, cardiac arrest, or mortality is 10.1% |
| 3 or more | Risk of 30-day MI, cardiac arrest, or mortality is 15.0% |

This structured approach helps balance the decision-making process by providing a clear estimate of cardiac risk based on specific, patient-related factors.

The Revised Cardiac Risk Index (RCRI) is a clinical calculator used to estimate the risk of cardiac complications during the perioperative period in patients undergoing non-cardiac surgery. It is particularly useful for stratifying patients into different risk categories based on six identified risk factors: high-risk surgery, history of ischemic heart disease, history of congestive heart failure, history of cerebrovascular disease, insulin therapy for diabetes, and preoperative serum creatinine >2.0 mg/dL. 

The RCRI is not applicable to patients undergoing cardiac surgery, as it was specifically designed for non-cardiac surgical procedures. It also may not be as accurate in populations not represented in the original study, such as those with less common comorbidities or undergoing less common surgical procedures.

Revised Cardiac Risk Index for perioperative risks (RCRI)