How do I use the predicted major adverse cardiac events (MACE) rate to evaluate cardiac risk before non‑cardiac surgery?

Using MACE Prediction in Preoperative Risk Evaluation

Use the Revised Cardiac Risk Index (RCRI) as your primary tool to calculate predicted MACE rates, then apply risk-stratified management protocols based on the score: patients with RCRI 0-1 proceed directly to surgery, RCRI=2 requires functional capacity assessment, and RCRI≥3 mandates comprehensive cardiac monitoring with troponin surveillance. 1, 2

Understanding MACE Definition and Baseline Rates

• MACE is defined as the composite endpoint of nonfatal myocardial infarction or cardiac death occurring within 30 days after noncardiac surgery 3
• The overall MACE incidence in high-risk surgical populations ranges from 2.6% to 15.2% within 30 days, increasing to 20.6% at one year 3, 4
• Among patients undergoing noncardiac surgery, the vulnerable period for elevated MACE risk extends approximately 3-5 months postoperatively 4

Primary Risk Stratification: The RCRI System

RCRI Components (1 point each)

• History of ischemic heart disease (strongest independent predictor) 2, 5
• Congestive heart failure 2, 5
• Cerebrovascular disease 2, 5
• Preoperative insulin-dependent diabetes mellitus 2, 5
• Chronic kidney disease (creatinine >2.0 mg/dL) 2, 5
• High-risk surgery 2, 5

Risk Categories and Predicted MACE Rates

Low Risk (RCRI 0-1): <1% MACE

• RCRI=0: 0.4-0.5% predicted MACE 2
• RCRI=1: 0.9-1.3% predicted MACE 2
• Management: Proceed directly to surgery without additional cardiac testing 1, 2

Moderate Risk (RCRI=2): 4-7% MACE

• Management algorithm: 2, 5
  • First, assess functional capacity using the Duke Activity Status Index (DASI)
  • If functional capacity ≥4 METs (able to climb two flights of stairs): proceed to surgery without further testing 2
  • If functional capacity <4 METs or unknown: consider pharmacologic stress testing only if results would change management (lead to revascularization, medication adjustment, or surgical cancellation) 2, 5

High Risk (RCRI≥3): 9-11% MACE (up to 40.2% including myocardial injury)

• Management protocol: 2, 5
  • Measure baseline cardiac troponin preoperatively 5
  • Implement comprehensive intraoperative cardiac monitoring 2, 5
  • Measure troponin at 24 hours, 48 hours, and 48-72 hours postoperatively 5
  • Assess functional capacity with DASI; if <4 METs, stress testing only if results alter management 2
  • Document blood pressure, heart rate, and cardiac physical examination within 2 hours before surgery 5

Enhancing RCRI Predictive Accuracy

Functional Capacity Assessment (Class IIa)

• Use the 12-item DASI questionnaire for patients with RCRI≥1 undergoing elevated-risk surgery 2
• DASI scores ≤34 indicate increased odds of 30-day death or MI 1, 2
• Functional capacity <4 METs confers a 1.63-fold higher rate of death, MI, acute heart failure, or life-threatening arrhythmias 2
• The two-flight stairs test provides a practical bedside alternative: inability to climb two flights indicates <4 METs 5, 6

Biomarker Enhancement (Class IIa)

• Measure preoperative BNP or NT-proBNP in patients with RCRI≥2 to improve risk discrimination 1, 2
• BNP adds a median Δc-statistic of 0.15 to RCRI alone; NT-proBNP adds 0.08 1, 2
• Abnormal thresholds: BNP >92 ng/L; NT-proBNP ≥300 ng/L 2
• Combining BNP with troponin yields an additional median Δc-statistic improvement of 0.12 2

Alternative Risk Calculators for Specific Populations

When RCRI Is Insufficient

Vascular Surgery Patients:

• The RCRI substantially underestimates cardiac risk in vascular surgery by 1.7- to 7.4-fold 5
• Use the ACS NSQIP Myocardial Infarction and Cardiac Arrest (MICA) calculator instead 1, 2
• The MICA calculator incorporates 21 variables and demonstrates a median Δc-statistic increase of ≈0.11 compared to RCRI 1, 2
• The MICA calculator has excellent predictive ability for MACE (AUC 0.93) comparable to RCRI in validation studies 7

Thoracic Surgery Patients:

• Use the Thoracic Revised Cardiac Risk Index (ThRCRI) instead of standard RCRI 2, 5
• ThRCRI weights factors such as ischemic heart disease, cerebrovascular disease, serum creatinine, and pneumonectomy specifically for thoracic procedures 2

Critical Pitfalls in MACE Risk Assessment

Timing of Surgery After Coronary Stenting

• Early surgery (within required dual-antiplatelet therapy period): 13.3% MACE rate 3
• Late surgery (after dual-antiplatelet therapy period): 0.6% MACE rate 3
• Discontinuation of antiplatelet therapy in the early-surgery group resulted in 30.7% MACE (all fatal) versus 0% in patients who continued therapy 3
• Bare-metal stents require 4-6 weeks for endothelialization; delay elective surgery accordingly 3
• Drug-eluting stents: sirolimus stents require 3 months, paclitaxel stents require 6 months before elective surgery 3

Special High-Risk Populations

• Adults aged ≥75 years: 9.5% MACE rate versus 4.8% in younger adults 2, 6
• Patients with coronary stents: 8.9% MACE rate versus 1.5% without stents 2, 6
• Carotid endarterectomy patients with CAD: 18.8% MACE incidence; preoperative coronary revascularization reduces this risk (OR 0.184) 8

Interventions to Avoid (Class III: No Benefit)

• Do not perform routine preoperative coronary angiography—it does not improve perioperative outcomes 2, 5, 6
• Do not initiate high-dose beta-blockers (e.g., metoprolol 100 mg) 2-4 hours before surgery—associated with higher stroke rates (1.0% vs 0.5%) and mortality (3.1% vs 2.3%) 2, 6
• Do not use routine low-dose aspirin (≈100 mg/day) perioperatively—does not reduce cardiovascular events but increases surgical bleeding 2, 6
• Do not perform routine coronary revascularization solely to lower perioperative risk 2, 6

Recommended Perioperative Medical Management

• Continue beta-blockers in all patients already taking them chronically (Class I) 5
• Continue statins in all patients currently taking them (Class I); associated with lower mortality (1.8% vs 2.3%) 5, 6
• Continue ACE inhibitors or ARBs perioperatively (Class IIa) 5
• Continue aspirin in patients with bare-metal stents; weigh bleeding risk against stent thrombosis risk 3