Key Takeaways
- Adopt the new stepwise framework to determine when pre‑operative cardiac evaluation is required.
- Use RCRI, NSQIP, or AUB‑HAS2 tools to identify patients with ≥1% risk of major adverse cardiovascular events.
- Recognize Myocardial Injury after Noncardiac Surgery (MINS) as a distinct, high‑risk entity.
- Assess functional capacity with METs; 4 METs (e.g., climbing two flights of stairs) marks lower perioperative risk.
- Involve a multidisciplinary team for complex cases, avoiding reflex testing that does not change management.
1. Introduction: A New Standard for Surgical Safety
Surgery remains a massive component of American healthcare, with approximately 14.4 million inpatient and 19.2 million ambulatory procedures performed annually in the United States. Given the high prevalence of cardiovascular disease among these patients—where nearly 25% of surgical inpatients have diagnosed atherosclerotic cardiovascular disease (ASCVD)—managing perioperative risk is a non-negotiable clinical priority.
The newly released 2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM Guideline officially supersedes the 2014 version. As medical educators, we must emphasize that this update is not just a revision; it is a paradigm shift toward an integrated, evidence-based, team-centered approach.
What’s Changed The 2024 update standardizes the "Stepwise" cardiac assessment, provides rigorous timing for modern therapies like SGLT2 inhibitors, and emphasizes the elimination of low-value care. Critically, it recognizes Myocardial Injury after Noncardiac Surgery (MINS) as a distinct clinical entity with significant prognostic implications.
2. The Stepwise Framework: Navigating Preoperative Assessment
The guidelines introduce a "Stepwise Approach to Perioperative Cardiac Assessment" to clarify when surgery should proceed and when clinical logic dictates a pause for further evaluation.
The Decision Flow
- Emergency vs. Elective: Immediate threats to life or limb (Emergency) or urgent cases (within 24 hours) typically proceed to surgery with minimal evaluation.
- Acute Conditions: For elective cases, clinicians must first screen for Acute Coronary Syndrome (ACS), unstable cardiac arrhythmias, or decompensated heart failure.
- Multidisciplinary Team (MDT) Discussion: Complex cases, such as those involving patients with congenital heart disease or unstable conditions, require a team-based discussion to decide between surgery, noninvasive treatment, or palliation.
The Core Philosophy Screening and treatment for surgical patients must adhere to the same indications as for non-surgical patients. We must avoid "reflex testing" that delays surgery without changing management. Only order tests that would be indicated independent of the planned procedure.
3. Risk Stratification: Tools Beyond the Stethoscope
Estimating the likelihood of a Major Adverse Cardiovascular Event (MACE) is the cornerstone of planning. The guidelines define Elevated Risk as a calculated ≥1% risk of MACE.
Primary Risk Assessment Tools
| Tool | Description | Components | Threshold for Elevated Risk |
|---|---|---|---|
| Revised Cardiac Risk Index (RCRI) | A simple, 6-predictor tool for major complications. | History of HF, CAD, cerebrovascular disease, insulin use, creatinine ≥2.0 mg/dL, high-risk surgery. | RCRI >1 |
| Universal NSQIP Surgical Risk Calculator | A 21-component comprehensive tool. | Functional status, age, emergency status, and extensive comorbidities. | Calculated Risk ≥1% |
Clinical Synthesis: Beyond these tools, the AUB-HAS2 index is highlighted for its ease of calculation using six data elements. Furthermore, a high-impact synthesis point for modern practice is that risk stratification can be enhanced by combining these tools with existing coronary calcium burden findings from non-gated chest CTs performed within one year of surgery.
4. Functional Capacity and the "Stair Climb" Test
Clinicians must prioritize the assessment of functional capacity, as it is one of the strongest predictors of outcomes. We use Metabolic Equivalents (METs), with 4 METs serving as the critical threshold.
- The Practical Test: If a patient can climb two flights of stairs, they generally exceed the 4-MET threshold and are considered lower risk.
- Duke Activity Status Index (DASI): This structured, patient-reported tool is superior to subjective clinician assessment.
- The Threshold: A DASI score of ≤34 is a major red flag, associated with significantly increased odds of 30-day death or MI.
5. Pruning the Protocol: Avoiding Low-Value Care
To eliminate unnecessary surgical delays, we must stop ordering tests that provide no clinical benefit.
- 12-Lead ECG: Not recommended for asymptomatic patients in low-risk procedures. It adds little prognostic value beyond standard risk tools.
- Stress Testing: Perform this only if it would be indicated independent of the surgery.
- LV Function Assessment: Do not order routine echoes for stable, asymptomatic patients. It does not improve outcomes.
- CCTA: Not for routine assessment. Clinical Rationale: CCTA is more than five times as likely to inappropriately overestimate risk in patients who will not experience a MACE, leading to dangerous delays and unnecessary invasive interventions.
Clinical Pearl: If a patient has a documented Coronary Calcium Score of 0 within the last two years, they are effectively "cleared" to proceed without further preoperative cardiac testing.
6. The SGLT2i Alert: Crucial Medication Timing
Sodium-glucose cotransporter 2 (SGLT2) inhibitors pose a unique risk for perioperative euglycemic ketoacidosis. We must be authoritative in our instructions to withhold these medications:
- Discontinue 3 Days Before Surgery: Canagliflozin, dapagliflozin, and empagliflozin.
- Discontinue 4 Days Before Surgery: Ertugliflozin.
7. Managing Comorbidities: CAD and Hypertension
- Coronary Artery Disease (CAD): Routine preoperative revascularization is not recommended for non-left main CAD solely to reduce perioperative events. However, we must identify patients with Left Main stenosis ≥50%—these patients are the exception and require a pause for revascularization and deferral of elective surgery.
- Blood Pressure Management: To reduce the risk of myocardial injury, we must maintain intraoperative Mean Arterial Pressure (MAP) ≥60–65 mm Hg AND Systolic Blood Pressure (SBP) ≥90 mm Hg.
- Atrial Fibrillation (AF): New-onset perioperative AF (POAF) is not a benign event; it is associated with increased stroke risk and requires diligent long-term anticoagulation assessment.
8. Conclusion: The "Heart-Smart" Checklist
The 2024 guidelines demand a shift from "clearing" a patient to "managing" a patient through shared decision-making.
Actionable Checklist
- Utilize Team-Based Care: Involve surgeons and anesthesiologists early for any high-risk anatomy or unstable disease.
- Apply Validated Risk Tools: Identify patients with ≥1% MACE risk using RCRI or NSQIP.
- Assess Functional Capacity: Prioritize DASI scores; flag any score ≤34.
- Order Biomarkers Judiciously: Measure BNP/NT-proBNP in patients Age ≥65 or Age ≥45 with symptoms suggestive of CVD to refine risk.
- Screen for Calcium: Check for a Calcium Score of 0 within the last 2 years to avoid further testing.
- Monitor for MINS: Treat myocardial injury after noncardiac surgery as a distinct, high-risk disease process.
- Timed Medication Cessation: Ensure SGLT2i are stopped 3–4 days prior to surgery as specified.
The ultimate goal of perioperative management is a patient-centered approach where every test is weighed against its power to actually change the outcome. Stay heart-smart, and keep your patients safe.