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Revised Cardiac Risk Index (RCRI)の包括的な教育ガイドを準備中です。ステップバイステップの解説、数式、実例、専門家のヒントをお届けしますので、もうしばらくお待ちください。
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.
RCRI Score = sum of the following 6 binary criteria (each = 1 point if present): 1. High-risk surgery: Suprainguinal vascular surgery (aortic, iliac, femoral), intrathoracic surgery (thoracotomy, lung resection, oesophagectomy), or intraperitoneal surgery (open abdominal procedures including bowel resection, gastrectomy, hepatic resection) 2. Ischaemic heart disease (IHD): History of myocardial infarction (prior MI), current or prior angina pectoris, use of nitrates, positive exercise or pharmacological stress test, or pathological Q waves on resting ECG 3. Congestive heart failure (CHF): History of heart failure, pulmonary oedema, bilateral basal crackles on examination, S3 gallop, paroxysmal nocturnal dyspnoea, or radiographic evidence of pulmonary vascular redistribution 4. Cerebrovascular disease: History of ischaemic stroke, transient ischaemic attack (TIA), or carotid artery stenosis with associated neurological symptoms 5. Insulin-dependent diabetes mellitus: Current use of insulin therapy for diabetes control (not metformin or other oral hypoglycaemics alone) 6. Preoperative creatinine > 177 µmol/L (> 2.0 mg/dL): Elevated preoperative serum creatinine indicating significant chronic kidney disease Maximum RCRI score = 6 MACE Risk: Score 0 = ~0.5%, Score 1 = ~1.3%, Score 2 = ~4%, Score ≥ 3 = ~9%+
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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).
Very low perioperative cardiac risk — proceed with standard care
Hip replacement is intermediate-risk surgery (not suprainguinal vascular, intrathoracic, or intraperitoneal), so the high-risk surgery criterion is not met. No IHD, CHF, cerebrovascular disease, insulin-dependent diabetes, or elevated creatinine. With a RCRI of 0 and excellent functional capacity (> 4 METs), preoperative cardiac investigation is not indicated. Routine ECG and bloods suffice. Standard intraoperative monitoring is appropriate.
High perioperative cardiac risk — cardiology referral and preoperative optimisation recommended
Three RCRI criteria are present: intraperitoneal surgery (colectomy) scores for high-risk surgery; nitrate use for stable angina confirms IHD; prior TIA confirms cerebrovascular disease. Metformin-only diabetes does not score. Creatinine is normal. Despite adequate functional capacity, a score of 3 places this patient in the high-risk category. A preoperative cardiology review should be sought. Statin therapy should be started or optimised. Perioperative beta-blocker continuation is indicated (already on bisoprolol). Enhanced postoperative monitoring — including high-dependency or troponin surveillance — should be considered.
Very high perioperative cardiac risk — multidisciplinary team discussion essential
Five of six RCRI criteria are present: suprainguinal vascular surgery (aortic aneurysm repair) is the highest-risk surgical category; prior MI and PCI confirm IHD; ischaemic cardiomyopathy with EF 35% confirms CHF; insulin-dependent diabetes scores; creatinine > 177 µmol/L confirms significant CKD. No prior cerebrovascular events. With a score of 5 and severely reduced functional capacity (< 4 METs), this patient requires urgent cardiology and anaesthetic review. Consideration should be given to endovascular repair (EVAR) as a lower-risk alternative, optimisation of heart failure therapy, perioperative haemodynamic monitoring, and a frank risk-benefit discussion with the patient. Postoperative troponin surveillance and high-dependency care should be planned.
Urgent surgery — RCRI provides baseline cardiac risk context; clinical urgency overrides routine preoperative assessment
Intraperitoneal surgery (laparotomy) scores 1 point for high-risk surgery. No other RCRI criteria are present. However, this is an emergency procedure — clinical urgency mandates proceeding to theatre without delay. The RCRI score characterises cardiac risk but does not alter the decision to operate. Importantly, emergency surgery carries independently higher cardiac risk than the same elective procedure. Intraoperative arterial line monitoring, postoperative troponin surveillance at 24 and 48 hours (as per ESC VISION protocol), and early senior anaesthetic involvement are appropriate measures.
Preoperative anaesthetic assessment clinics — RCRI is calculated as part of routine preoperative workup for all patients undergoing intermediate- or high-risk elective non-cardiac surgery, guiding the need for cardiology referral, echocardiography, stress testing, and preoperative medication optimisation
Perioperative beta-blocker and statin management — patients with RCRI ≥ 2 undergoing high-risk surgery are identified for preoperative statin initiation (if not already prescribed) and cautious perioperative beta-blocker management in line with 2022 ESC guideline recommendations
Surgical consent and shared decision-making — RCRI risk estimates are used to communicate personalised 30-day MACE risk in plain language to patients, supporting informed consent and enabling shared decisions about whether to proceed with elective surgery or pursue non-surgical alternatives
Postoperative surveillance planning — patients with RCRI ≥ 1 undergoing intermediate- or high-risk surgery are flagged for postoperative high-sensitivity troponin measurement at 24 and 48 hours (MINS surveillance), with those in elevated-risk categories allocated to high-dependency or intensive care postoperative settings
Clinical audit and quality improvement — RCRI scores are documented as part of national perioperative quality registries (e.g., PQIP in the UK, ACS NSQIP in the US) to benchmark cardiac risk-adjusted surgical outcomes across institutions and identify practice variation in preoperative cardiac optimisation
Emergency and urgent surgery
When surgery is required urgently or emergently (e.g., perforated viscus, ruptured AAA, acute bowel obstruction, trauma), there is insufficient time for standard preoperative cardiac optimisation. In these situations, RCRI provides useful background context to guide intraoperative monitoring intensity and postoperative surveillance, but it cannot and should not delay life-saving surgery. The 2022 ESC guidelines recommend ensuring optimal haemodynamic management intraoperatively and implementing troponin surveillance at 24 and 48 hours postoperatively (MINS — myocardial injury after non-cardiac surgery) in high-risk patients identified by RCRI.
Patients already on beta-blockers
RCRI does not directly guide decisions about beta-blocker initiation — that requires separate clinical judgment. However, patients already taking beta-blockers (for IHD, CHF, hypertension, or rate control) should have these continued perioperatively without interruption. Abrupt withdrawal of beta-blockers before surgery is associated with rebound sympathetic activation, tachycardia, and increased ischaemia risk. The RCRI finding of IHD or CHF in a patient already on beta-blockers supports continuation, and any dose adjustments should be made in consultation with anaesthetics and cardiology.
Chronic kidney disease and the creatinine criterion
The RCRI creatinine threshold of > 177 µmol/L (> 2.0 mg/dL) captures patients with significant CKD (roughly CKD stage 3b-4). However, in elderly, frail, or cachectic patients with low muscle mass, creatinine can significantly underestimate renal impairment — a creatinine of 130 µmol/L may represent eGFR < 30 mL/min/1.73m² in a 75-year-old woman. For these patients, eGFR should be reviewed alongside absolute creatinine. CKD independently elevates cardiovascular risk through mechanisms beyond RCRI including accelerated atherosclerosis, autonomic dysfunction, and fluid dysregulation, and should prompt careful perioperative fluid and medication management even if the creatinine criterion is technically not met.
Postoperative troponin surveillance (MINS)
Myocardial Injury after Non-cardiac Surgery (MINS) — defined as troponin elevation within 30 days of surgery without an alternative non-ischaemic cause — affects approximately 8% of patients over 45 years old and is associated with 30-day mortality of 10%. The 2022 ESC guidelines recommend routine postoperative troponin measurement at 24 and 48 hours in patients with RCRI ≥ 1 undergoing intermediate- or high-risk surgery. Most MINS episodes are silent — the patient does not experience classic chest pain — making surveillance troponin the only detection method. MINS warrants urgent cardiology review and initiation of aspirin and statins.
Functional capacity as a complementary assessment
RCRI does not incorporate functional capacity (exercise tolerance), yet the 2022 ESC guidelines consider functional capacity a key modifier of cardiac risk. Patients with RCRI ≥ 2 but excellent functional capacity (≥ 10 METs — competitive sport level) may not need additional cardiac investigations before surgery. Conversely, patients with RCRI 1 but severely limited functional capacity (< 4 METs) may warrant further evaluation. The Duke Activity Status Index (DASI) or a simple question — 'Can you climb two flights of stairs without stopping?' — provides a rapid functional capacity screen. Poor functional capacity combined with elevated RCRI is the highest-risk combination.
| RCRI Score | Number of Risk Factors | Estimated MACE Risk | Clinical Action |
|---|---|---|---|
| 0 | None | ~0.5% | Very low risk — proceed with routine preoperative care; no additional cardiac workup needed |
| 1 | 1 factor | ~1.3% | Low risk — standard monitoring; ensure existing cardiac medications are optimised and continued perioperatively |
| 2 | 2 factors | ~4% | Intermediate risk — consider cardiology review; assess functional capacity; optimise statin and antihypertensive therapy; plan enhanced monitoring |
| ≥ 3 | 3 or more factors | ~9%+ | High risk — cardiology referral recommended; preoperative investigations as indicated (ECG, echocardiography, NT-proBNP); MDT discussion for high-risk cases; plan HDU/ICU postoperative care |
What does the RCRI measure and when should it be used?
The RCRI estimates the probability of major adverse cardiac events (MACE) — including non-fatal MI, non-fatal cardiac arrest, pulmonary oedema, complete heart block, and cardiac death — occurring within 30 days of non-cardiac surgery. It should be applied to any patient aged 18 or older undergoing elective or semi-elective non-cardiac surgery where preoperative cardiac risk assessment is clinically appropriate, particularly for intermediate- and high-risk surgical procedures. It is not designed for emergency surgery (where urgency overrides risk-guided workup) or cardiac surgery itself.
Does a high RCRI score mean surgery should be cancelled?
No. A high RCRI score does not in itself contraindicate surgery. Rather, it triggers additional evaluation, optimisation, and planning. For elective procedures, a high RCRI warrants preoperative cardiology assessment, optimisation of heart failure, IHD, and diabetic management, consideration of lower-risk surgical alternatives (e.g., EVAR instead of open AAA repair, laparoscopic instead of open bowel resection), and planning for enhanced perioperative monitoring and postoperative care. The ultimate decision is a shared one between surgeon, anaesthetist, cardiologist, and patient, weighing the benefit of surgery against the cardiovascular risk.
How does the RCRI differ from the ESC surgical risk classification?
The ESC/ESA 2022 guidelines use a two-layer approach: first, surgical risk category (low < 1%, intermediate 1–5%, high > 5% 30-day MACE) based on procedure type alone; second, patient-specific risk estimation using tools such as the RCRI. The ESC surgical risk category assigns inherent risk to the operation regardless of the patient, whereas RCRI integrates patient comorbidities with surgery type to give a personalised risk estimate. Both tools are complementary and are both used in the 2022 ESC perioperative guidelines.
Which patients need preoperative cardiac investigations beyond the RCRI?
The 2022 ESC guidelines recommend preoperative echocardiography or stress testing when the RCRI is ≥ 2 and functional capacity is < 4 METs (i.e., unable to climb two flights of stairs or walk briskly on flat ground), or when new cardiac symptoms have not been previously investigated. Patients with known severe valvular disease (particularly severe aortic stenosis), reduced ejection fraction, or pulmonary hypertension may need additional evaluation regardless of RCRI score. Routine ECG is recommended for patients undergoing intermediate- or high-risk surgery. Routine echocardiography is not indicated for low RCRI scores.
Should perioperative beta-blockers be started based on the RCRI?
Perioperative beta-blocker use is nuanced and must follow current evidence, not RCRI alone. Patients already on beta-blockers should continue them perioperatively — abrupt discontinuation increases rebound ischaemia risk. The 2022 ESC guidelines recommend considering initiating beta-blockers preoperatively for patients with known IHD or myocardial ischaemia undergoing high-risk surgery. However, the POISE trial demonstrated that starting high-dose metoprolol immediately before surgery in unselected patients increased stroke risk and mortality despite reducing MI. Beta-blockers should be initiated at low dose, well before surgery (at least 7–30 days), and titrated to heart rate. Cardiology guidance is essential.
Is the RCRI validated in patients undergoing vascular surgery?
The RCRI was derived in a mixed surgical population and performs reasonably well in vascular surgery, but its discriminative accuracy is lower in high-risk vascular populations where baseline cardiac risk is already high. Some vascular surgery guidelines supplement RCRI with functional capacity assessment, NT-proBNP measurement, or stress imaging in high-RCRI patients. The Vascular Quality Initiative (VQI) Cardiac Risk Index was developed specifically for vascular surgery and may offer superior discrimination in that subgroup. The ESC 2022 perioperative guidelines retain RCRI as the primary screening tool across all non-cardiac surgical specialties.
What role does NT-proBNP or BNP play alongside the RCRI?
Measurement of NT-proBNP or BNP is endorsed by the 2022 ESC guidelines as an adjunct to RCRI for intermediate- and high-risk non-cardiac surgery. Elevated preoperative NT-proBNP (> 300 ng/L) or BNP (> 92 ng/L) independently predicts 30-day MACE and mortality, even in patients with a low or intermediate RCRI. The VISION cohort study showed that preoperative NT-proBNP significantly improves cardiac risk stratification beyond clinical risk scores alone. In patients with RCRI ≥ 1 undergoing intermediate- or high-risk surgery, baseline NT-proBNP measurement is now a Class IIa recommendation in ESC 2022 guidelines.
How should RCRI results be communicated to patients?
Patients should receive a clear, jargon-free explanation of their perioperative cardiac risk before consenting to surgery, particularly for elective procedures. Rather than presenting the RCRI score as a number, frame the risk in absolute terms: for example, 'Based on your medical history, approximately 4 in 100 patients like you experience a serious heart complication within 30 days of this operation.' Explain what this means for their care — additional monitoring, optimisation of medications, specialist review — and ensure they understand it does not necessarily mean surgery should not proceed. Shared decision-making is fundamental, especially when the surgical indication is non-urgent.
プロのヒント
Always combine RCRI with a functional capacity assessment before deciding whether preoperative cardiac investigations are needed. A patient with RCRI ≥ 2 who can climb two flights of stairs without symptoms (≥ 4 METs) can often proceed to intermediate-risk surgery without further cardiac workup, while a patient with RCRI 1 and severely limited exercise tolerance may warrant echocardiography or stress testing. Also measure NT-proBNP in RCRI ≥ 1 patients undergoing intermediate- or high-risk surgery — a normal NT-proBNP is highly reassuring even in the presence of comorbidities.
ご存知でしたか？
The RCRI was derived from just 4,315 patients in 1999 using only six simple clinical questions, yet it has been validated in studies involving over 790,000 surgical patients across multiple countries, healthcare systems, and surgical specialties. Despite 25 years of research and the development of many competing risk scores (ACS-NSQIP, NSQIP MICA, vascular-specific tools), no subsequent model has consistently outperformed the RCRI in external validation studies for general non-cardiac surgical populations — a remarkable testament to the power of carefully selected, clinically intuitive predictors over statistical complexity.
参考文献
- ›Lee TH et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery — Circulation 1999
- ›Devereaux PJ et al. Characteristics and short-term prognosis of perioperative myocardial infarction in patients undergoing noncardiac surgery — Ann Intern Med 2011
- ›Halvorsen S et al. 2022 ESC Guidelines on cardiovascular assessment and management of patients undergoing non-cardiac surgery — Eur Heart J 2022
- ›Devereaux PJ et al. Association of Postoperative High-Sensitivity Troponin Levels With Myocardial Injury and 30-Day Mortality Among Patients Undergoing Noncardiac Surgery (VISION) — JAMA 2017
- ›Fleisher LA et al. 2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery — J Am Coll Cardiol 2014