RCRI Scoring and Risk Stratification for Noncardiac Surgery
The Revised Cardiac Risk Index (RCRI) stratifies perioperative cardiac risk using six independent predictors, with 0 factors indicating low risk (0.4-0.5% MACE), 1 factor indicating low-moderate risk (0.9-1.3% MACE), 2 factors indicating intermediate risk (4-7% MACE), and ≥3 factors indicating high risk (9-11% MACE). 1, 2
The Six RCRI Risk Factors
The RCRI assigns one point for each of the following clinical predictors 3, 4:
- High-risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular procedures) 3, 2
- History of ischemic heart disease (prior MI, positive stress test, current angina, nitroglycerin use, or Q waves on ECG) 3, 4
- History of congestive heart failure (prior heart failure, pulmonary edema, paroxysmal nocturnal dyspnea, S3 gallop, or pulmonary vascular redistribution on chest X-ray) 3, 4
- History of cerebrovascular disease (prior stroke or transient ischemic attack) 3, 2
- Preoperative insulin treatment for diabetes mellitus 3, 4
- Preoperative renal insufficiency (serum creatinine >2.0 mg/dL or GFR <30 mL/min) 3, 2
Risk Categories and Associated MACE Rates
Low Risk (RCRI = 0)
- Major adverse cardiac event rate: 0.4-0.5% 1, 2, 4
- Proceed directly to surgery without additional cardiac testing 2, 5
- Continue chronic beta-blockers and statins if already prescribed 2
Low-Moderate Risk (RCRI = 1)
- Major adverse cardiac event rate: 0.9-1.3% 1, 2, 4
- Proceed to surgery without additional cardiac testing 2
- Continue chronic medications including beta-blockers and statins 2
Intermediate Risk (RCRI = 2)
- Major adverse cardiac event rate: 4-7% 1, 2, 4
- Assess functional capacity using metabolic equivalents (METs) 1, 2
- Consider pharmacological stress testing only if functional capacity is poor (<4 METs) and results would change management 1, 2
- Continue chronic beta-blockers and statins 2
High Risk (RCRI ≥3)
- Major adverse cardiac event rate: 9-11% 1, 2, 4
- Implement comprehensive cardiovascular examination including vital signs, carotid pulse assessment, jugular venous pressure, lung auscultation for crackles, and peripheral vascular examination 1, 5
- Consider pharmacological stress testing if functional capacity is poor or unknown and results would impact management 1, 5
- Initiate beta-blockers more than 1 day before surgery to assess safety and tolerability 1, 5
- Continue statins in all patients currently taking them, and initiate statin therapy preoperatively in patients with atherosclerotic cardiovascular disease 1
- Implement comprehensive cardiac monitoring during surgery with continuous ECG monitoring 1, 5
- Consider postoperative surveillance for myocardial injury after noncardiac surgery (MINS) with serial troponin measurements 1, 5
Active Cardiac Conditions That Override RCRI Scoring
The presence of any active cardiac condition mandates intensive management and may require delay or cancellation of elective surgery 3:
- Unstable coronary syndromes 3, 1
- Unstable or severe angina 3
- Recent MI (within 7 days to 1 month with evidence of ischemic risk) 3
- Decompensated heart failure 3, 1
- Significant arrhythmias 3
- Severe valvular disease 3
Important Caveats and Limitations
The RCRI may underestimate risk in vascular surgery patients, particularly those undergoing lower extremity bypass, endovascular AAA repair, and open AAA repair, where actual event rates can be 1.7- to 7.4-fold higher than predicted 6. For vascular surgery specifically, the Vascular Study Group Cardiac Risk Index (VSG-CRI) demonstrates superior predictive accuracy 6.
Adding biomarkers improves RCRI performance: NT-proBNP and troponin addition to the RCRI improves discrimination for MACE prediction, with median delta c-statistics of 0.08 and 0.14, respectively 7. When used alone, BNP and NT-proBNP may outperform the RCRI with median delta c-statistics of 0.15 and 0.12, respectively 7.
Functional capacity assessment is critical: Patients who cannot achieve ≥4 METs during daily activities have poor functional capacity and warrant additional evaluation regardless of RCRI score 1, 2, 5.
Anemia correction is essential: Hematocrits <28% are associated with increased perioperative ischemia and complications, particularly in vascular surgery patients 3, 5.