Should we assess both Major Adverse Cardiac Events (MACE) and the Revised Cardiac Risk Index (RCRI) in peri‑operative patients with a known cardiac condition?

Perioperative Cardiac Risk Assessment: RCRI and MACE Evaluation

You should use the RCRI to calculate the risk of MACE, not assess them as separate entities—MACE is the outcome that RCRI predicts. The RCRI is a validated tool that estimates the probability of major adverse cardiac events (MACE) occurring perioperatively, making them intrinsically linked rather than independent assessments 1.

Understanding the Relationship Between RCRI and MACE

The RCRI serves as the primary risk stratification tool that predicts the likelihood of MACE (defined as myocardial infarction, cardiac arrest, pulmonary edema, ventricular fibrillation, or complete heart block) 1. The 2024 AHA/ACC guidelines explicitly recommend using RCRI >1 or a calculated risk of MACE >1% as the threshold to identify patients at elevated risk 1.

The Integrated Assessment Algorithm

Step 1: Calculate RCRI Score

• Assign one point for each of six predictors: history of ischemic heart disease, congestive heart failure, cerebrovascular disease, insulin-dependent diabetes, chronic kidney disease (creatinine >2 mg/dL), and high-risk surgery 1, 2

Step 2: Interpret MACE Risk Based on RCRI

• RCRI 0-1 (Low Risk): <1% risk of MACE—proceed directly to surgery without additional cardiac testing 1, 3
• RCRI = 2 (Moderate Risk): 4-7% risk of MACE—assess functional capacity; if ≥4 METs, proceed to surgery 1, 2
• RCRI ≥3 (High Risk): 9-11% risk of MACE—implement comprehensive cardiac monitoring and consider stress testing only if results would change management 1, 2

Enhanced Risk Stratification Beyond Basic RCRI

For patients with RCRI ≥1 undergoing elevated-risk surgery, the 2024 guidelines recommend augmenting RCRI with:

Functional Capacity Assessment

• Use the Duke Activity Status Index (DASI) to measure functional capacity 1, 2
• DASI scores ≤34 are associated with increased odds of 30-day death or MI 2
• Adding functional capacity to RCRI significantly increases predictive power 2, 4

Biomarker Enhancement

• Preoperative BNP/NT-proBNP measurement (Class 2a recommendation): Improves discrimination with median delta c-statistic of 0.08 for NT-proBNP and 0.15 for BNP compared to RCRI alone 1, 4
• Preoperative troponin (Class 2b recommendation): Median delta c-statistic improvement of 0.14 when added to RCRI 4
• The combination of NT-proBNP and troponin provides median delta c-statistic improvement of 0.12 4
• Abnormal thresholds: troponin >99th percentile, BNP >92 ng/L, NT-proBNP ≥300 ng/L 1

Perioperative Troponin Surveillance

• For patients with RCRI ≥2, consider postoperative troponin surveillance at 48-72 hours 5
• Perioperative increases in hs-cTnT ≥14 ng/L above baseline identifies acute myocardial injury and provides net prognostic benefit over RCRI alone 6

Alternative Risk Calculators

When RCRI may be insufficient:

• The ACS NSQIP MICA calculator uses 21 components and may provide superior predictive discrimination, particularly in broader surgical populations (median delta c-statistic 0.11 higher than RCRI for predicting MI and cardiac arrest) 1, 5, 4
• The universal ACS NSQIP Surgical Risk Calculator provides procedure-specific risk estimates using CPT codes rather than broad surgical categories 2, 5
• For thoracic surgery specifically, consider the Thoracic RCRI (ThRCRI) instead of standard RCRI 5

Common Pitfalls to Avoid

Do not order stress testing reflexively for elevated RCRI scores. Stress testing should only be performed if: (1) the patient has poor functional capacity (<4 METs) or unknown functional capacity, AND (2) abnormal results would lead to coronary revascularization, medication changes, or surgical cancellation 1, 5.

Do not perform routine preoperative coronary angiography—it is not recommended to improve perioperative outcomes (Class 3: No Benefit) 1, 5.

Emergency surgery increases cardiac risk regardless of RCRI score, so focus should shift to immediate perioperative medical optimization rather than extensive testing 5.

RCRI performs poorly in vascular surgery populations, where alternative tools like NSQIP MICA should be considered 5, 7.

Clinical Decision Framework

For patients with known cardiac conditions:

1. Calculate RCRI to estimate MACE risk (not as separate assessments) 1
2. If RCRI ≥1 with elevated-risk surgery: Add functional capacity assessment via DASI 1, 2
3. If RCRI ≥2: Consider preoperative BNP/NT-proBNP measurement 1, 4
4. If poor functional capacity (<4 METs) and RCRI ≥2: Consider stress testing only if results would change management 1
5. Proceed to surgery with guideline-directed medical therapy (continue beta-blockers, statins, consider ACE inhibitors/ARBs) 3