What is the interpretation and management of an elevated Rcri (Renal Chronic Risk Index) score?

Understanding and Managing the Revised Cardiac Risk Index (RCRI)

What is the RCRI?

The RCRI is a validated 6-point scoring system used to predict perioperative cardiac complications in patients undergoing non-cardiac surgery, with each risk factor contributing 1 point to calculate a patient's total score. 1, 2

The six RCRI components are:

• History of ischemic heart disease 1, 3
• History of congestive heart failure 1, 3
• History of cerebrovascular disease (stroke/TIA) 1, 3
• Preoperative insulin-dependent diabetes mellitus 1, 3
• Chronic renal dysfunction (serum creatinine >2.0 mg/dL or >177 µmol/L) 1, 3
• High-risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular procedures) 1, 3

Risk Stratification Based on RCRI Score

Patients are classified into risk categories based on their total RCRI score, which directly determines the need for additional testing and perioperative management intensity. 2, 4

Low Risk (RCRI 0-1)

• Predicted major adverse cardiac event (MACE) risk: <1% 2, 4
• These patients can proceed directly to surgery without additional cardiac testing 2, 4
• Consider initiating guideline-directed medical therapy for long-term cardiovascular risk reduction 2
• A 12-lead ECG is reasonable in patients with established cardiovascular disease or symptoms 2

Moderate Risk (RCRI = 2)

• Predicted MACE risk: approximately 6.7% 5
• Functional capacity assessment is mandatory using the Duke Activity Status Index (DASI) 2, 4
• If functional capacity is excellent (≥4 METs), proceed to surgery without further testing 2, 4
• If functional capacity is poor (<4 METs) or unknown, pharmacological stress testing is reasonable only if results would change management (coronary revascularization, medication changes, or surgical cancellation) 2, 4
• Preoperative resting 12-lead ECG is reasonable for patients with known coronary disease or significant structural heart disease 2

High Risk (RCRI ≥3)

• Predicted MACE risk: 11.6-40.2% 3, 5
• Comprehensive preoperative cardiac monitoring is required with troponin measurement pre-operatively and at 24 and 48 hours post-surgery 3
• Functional capacity assessment using DASI is mandatory 3
• Consider pharmacological stress testing only if results would alter management decisions 3
• Blood pressure, heart rate, and cardiac physical examination must be documented within 2 hours before surgery 3
• Comprehensive preoperative laboratory evaluation including baseline cardiac troponin, complete blood count, renal function, and coagulation profile 3

Perioperative Medical Management

Continue all chronic cardiovascular medications perioperatively with specific attention to beta-blockers, statins, and ACE inhibitors/ARBs. 1, 2, 3

Beta-Blockers

• Continue beta-blockers in all patients already taking them chronically (Class I recommendation) 1, 2, 3
• Abrupt discontinuation can cause rebound hypertension 1
• For patients with RCRI ≥3 not on beta-blockers, it may be reasonable to initiate them before surgery, preferably more than 1 day in advance to assess safety and tolerability 1, 2
• Starting beta-blockers ≤1 day before surgery is ineffective and potentially harmful 1
• Manage beta-blockers after surgery based on clinical circumstances (hypotension, bradycardia, bleeding) 1

Statins

• Continue statins in all patients currently taking them (Class I recommendation) 2, 3

ACE Inhibitors/ARBs

• Continuation of ACE inhibitors or ARBs is reasonable perioperatively (Class IIa recommendation) 2, 3
• These medications have been associated with increased risk of intraoperative hypotension when continued 1

Blood Pressure Management

• Maintain intraoperative mean arterial pressure (MAP) ≥60-65 mm Hg or systolic blood pressure (SBP) ≥90 mm Hg to reduce risk of myocardial injury 1
• In patients with untreated hypertension and ≥1 RCRI component, preoperative SBP >160 mm Hg is associated with increased cardiac, neurological, or renal complications 1
• Intraoperative hypotension (MAP <65 mm Hg or SBP <90 mm Hg) for approximately 15 minutes is associated with postoperative myocardial injury, acute kidney injury, and mortality 1

Important Limitations and Special Populations

The RCRI substantially underestimates cardiac risk in vascular surgery patients by 1.7- to 7.4-fold, and alternative risk calculators should be used for these patients. 3, 6

Vascular Surgery

• The Vascular Study Group Cardiac Risk Index (VSG-CRI) more accurately predicts cardiac complications in vascular surgery patients 3, 6
• The RCRI predicted actual event rates of 2.6%, 6.7%, 11.6%, and 18.4% for patients with 0,1,2, and ≥3 risk factors in vascular surgery, compared to the originally predicted lower rates 6

Thoracic Surgery

• Use the Thoracic Revised Cardiac Risk Index (ThRCRI) instead of standard RCRI for thoracic surgery patients 2, 3, 7
• The ThRCRI uses weighted factors: ischemic heart disease (1.5 points), cerebrovascular disease (1.5 points), renal disease (1 point), and pneumonectomy (1.5 points) 2, 7
• The ThRCRI has higher discrimination (c-index 0.72 vs 0.62) compared to standard RCRI in lung resection candidates 7

Enhanced Risk Prediction

• Measuring NT-proBNP and/or troponin preoperatively enhances risk prediction for patients with RCRI ≥2 4
• The combination of NT-proBNP and troponin provides a median delta c-statistic improvement of 0.12 over RCRI alone 4
• The NSQIP MICA (Myocardial Infarction or Cardiac Arrest) calculator may provide superior discrimination compared to RCRI, with a median delta c-statistic of 0.11 higher 4

Postoperative Monitoring

Measure cardiac troponin at 48-72 hours after surgery in all patients with RCRI ≥2. 4, 3

• Use the surgical Apgar score <7 to identify patients requiring biomarker monitoring regardless of preoperative RCRI 4, 3
• Monitor creatinine weekly in patients with suspected immune checkpoint inhibitor-related nephritis 1

Common Pitfalls to Avoid

• Do not perform routine preoperative coronary angiography 2, 3
• Do not order stress testing unless abnormal results would change management 4, 3
• Do not use standard RCRI for vascular or thoracic surgery patients without considering procedure-specific risk calculators 3, 6, 7
• Do not start beta-blockers on the day of surgery or the day before—this is harmful 1
• Do not defer surgery solely based on elevated blood pressure <180/110 mm Hg in patients without RCRI components 1
• Emergency surgery increases cardiac risk regardless of RCRI score, and focus should be on immediate perioperative medical optimization rather than extensive testing 4