Revised Cardiac Risk Index (RCRI)

The Revised Cardiac Risk Index (RCRI), also known as the Lee Index, is the most widely used and validated clinical prediction tool for estimating the risk of major adverse cardiac events (MACE) in patients undergoing non-cardiac surgery. It was derived by Thomas H. Lee and colleagues and published in Circulation in 1999, based on a prospective cohort of 4,315 patients aged 50 or older undergoing elective non-cardiac surgery at two academic hospitals in the United States. MACE in the RCRI context includes non-fatal myocardial infarction, non-fatal cardiac arrest, pulmonary oedema, complete heart block, and cardiac death occurring within 30 days of surgery. These complications collectively represent the most serious cardiovascular outcomes of the perioperative period and carry significant mortality, morbidity, and resource burden. The RCRI identifies six independent, equally weighted predictors of perioperative MACE. Each predictor present scores 1 point, for a maximum score of 6. The resulting score stratifies patients into four risk categories with well-characterised MACE rates: 0 factors (~0.5%), 1 factor (~1.3%), 2 factors (~4%), and 3 or more factors (~9% or greater). The RCRI was subsequently validated in multiple large independent cohorts, most notably by Devereaux PJ and colleagues in a systematic review of over 790,000 patients. It is incorporated into the 2022 ESC/ESA Guidelines on Cardiovascular Assessment and Management of Patients Undergoing Non-cardiac Surgery, the 2014 ACC/AHA Guidelines on Perioperative Cardiovascular Evaluation, and national anaesthesia and surgical society guidelines worldwide. The RCRI informs key perioperative decisions including preoperative cardiology referral, the use of perioperative beta-blockers and statins, the need for preoperative cardiac investigations (e.g., echocardiography, stress testing), monitoring intensity, and the setting and level of postoperative care required. It remains the reference standard for preoperative cardiac risk stratification due to its simplicity, widespread validation, and clinical utility.

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1. 1Identify the planned surgical procedure and classify its cardiac risk tier. High-risk procedures (suprainguinal vascular, intrathoracic, intraperitoneal surgery) score 1 point for high-risk surgery. Intermediate-risk procedures (orthopaedic, prostate, head and neck surgery) and low-risk procedures (surface, endoscopic, cataract surgery) do not score this criterion. Cardiac risk of surgery is independently the strongest predictor in the RCRI.
2. 2Systematically review the patient's cardiovascular history for ischaemic heart disease. Ask specifically about prior MI (and approximate date), angina symptoms at rest or on exertion, use of sublingual or long-acting nitrates, and any prior positive stress test (exercise ECG, myocardial perfusion imaging, or stress echocardiography). Review the resting ECG for pathological Q waves (> 40 ms duration, > 1 mm depth, in two or more contiguous leads). Assign 1 point if any of these features is present.
3. 3Assess for congestive heart failure by history, examination, and available investigations. Ask about symptoms of breathlessness at rest or on minimal exertion, orthopnoea, paroxysmal nocturnal dyspnoea, and ankle swelling. Examine for raised JVP, S3 gallop, and bibasal crepitations. Review chest X-ray for cardiomegaly and pulmonary vascular redistribution. Review prior echocardiography for reduced ejection fraction. Assign 1 point if CHF is present or previously documented.
4. 4Screen for cerebrovascular disease by asking directly about prior strokes (with or without residual deficits) and transient ischaemic attacks (TIAs). TIAs — sudden-onset focal neurological deficits resolving within 24 hours — are frequently underreported by patients. Review medical records for neurology letters, imaging (CT/MRI brain), and carotid duplex reports if available. Assign 1 point for any prior stroke or TIA.
5. 5Determine insulin use in patients with diabetes. Only insulin-dependent diabetes scores 1 point in the RCRI — patients managing diabetes with diet alone or oral hypoglycaemics (metformin, GLP-1 agonists, SGLT-2 inhibitors) do not meet this criterion. Document the current diabetes regimen and glycaemic control (HbA1c). Poorly controlled diabetes (HbA1c > 8.5%) may warrant optimisation prior to elective surgery.
6. 6Review preoperative blood results for serum creatinine. A creatinine > 177 µmol/L (> 2.0 mg/dL) scores 1 point and reflects significant chronic kidney disease (approximately CKD stage 3b-4). Note that creatinine alone underestimates renal impairment in cachectic, elderly, or low-muscle-mass patients — consider eGFR alongside absolute creatinine. Preoperative CKD also has implications for contrast-based investigations, nephrotoxic drug avoidance, and postoperative fluid management.
7. 7Sum all six criteria to calculate the RCRI score (0–6). Apply the validated risk thresholds: RCRI 0 = very low risk (~0.5% MACE, surgery safe to proceed); RCRI 1 = low risk (~1.3%, generally safe with standard monitoring); RCRI 2 = intermediate risk (~4%, consider preoperative cardiology input, perioperative monitoring escalation, statin optimisation); RCRI ≥ 3 = high risk (~9%+, strong consideration for cardiology referral, functional capacity assessment, and discussion of surgical risk-benefit with patient and surgical team).

• !Applying the RCRI to patients undergoing cardiac surgery — the tool was specifically derived and validated for non-cardiac surgery only. For cardiac surgical risk (e.g., CABG, valve replacement), use the EuroSCORE II or STS risk calculator.
• !Scoring insulin-dependent diabetes incorrectly — only patients using insulin therapy score this criterion. Patients managed with diet, metformin, GLP-1 agonists, SGLT-2 inhibitors, or other oral hypoglycaemics alone do not score, regardless of HbA1c or diabetes severity.
• !Missing ischaemic heart disease by not asking about nitrate use — patients with stable angina managed with sublingual or long-acting nitrates often do not volunteer this history without direct questioning. Nitrate use alone is a positive IHD criterion even if the patient reports no chest pain at the time of assessment.
• !Classifying laparoscopic surgery as equivalent to open intraperitoneal surgery — laparoscopic cholecystectomy and appendicectomy carry lower cardiac risk than open intraperitoneal procedures. The RCRI high-risk surgery criterion was derived in an era of predominantly open surgery. The 2022 ESC guidelines note that minimally invasive alternatives to open surgery are associated with reduced MACE and should be preferred in high-RCRI patients when technically feasible.
• !Using RCRI in isolation without assessing functional capacity — a RCRI score of 2 in a patient who walks 5 km daily without symptoms carries a very different clinical profile from RCRI 2 in a patient who is dyspnoeic washing their face. The 2022 ESC guidelines explicitly require functional capacity assessment to be combined with RCRI to guide the need for preoperative investigations.
• !Failing to document and communicate the RCRI assessment to the perioperative team — a RCRI calculation that does not reach the anaesthetist, scrub nurse, and postoperative ward team loses its clinical value. RCRI findings should be documented in the preoperative assessment letter, surgical clerking, and anaesthetic plan, with clear implications stated for intraoperative monitoring level, postoperative care setting, and troponin surveillance.