Cardiovascular Evaluation

Cardiac Risk Assessment - Heart Checkup Time

• Goal: Identify patients at ↑ risk of perioperative Major Adverse Cardiac Events (MACE: MI, HF, CVA, death).
• Key Components:
  • Clinical History: Prior MI, HF, angina, arrhythmia, valvular disease.
  • Functional Capacity: Metabolic Equivalents (METs).
    • <4 METs (e.g., can't climb 1 flight of stairs) = Poor capacity, ↑ risk.

    • 4-10 METs = Moderate.

    • 10 METs = Excellent.

• Risk Stratification Tools:
  • Revised Cardiac Risk Index (RCRI) - 6 predictors (1 point each):
    • High-risk surgery
    • Ischemic Heart Disease (IHD)
    • Congestive Heart Failure (CHF)
    • History of Cerebrovascular Accident (CVA/TIA)
    • Insulin-dependent Diabetes Mellitus
    • Preoperative serum Creatinine >2 mg/dL
  • NSQIP MICA, Gupta MICA.

⭐ Functional capacity (METs) is a cornerstone of cardiac risk assessment; inability to perform activities ≥4 METs significantly increases perioperative cardiac risk.

Functional Capacity & METs - Stairway to Surgery

• METs (Metabolic Equivalents): Measure of exercise capacity. $1 \text{ MET} = \text{resting oxygen consumption} \approx 3.5 \text{ mL O}_2\text{/kg/min}$.
• Crucial for assessing perioperative risk; quantifies physiological reserve.
• Key MET Levels & Activities:
  • <4 METs (Poor): Self-care (e.g., eating, dressing), walking indoors, walking 1-2 blocks slowly. Associated with ↑ risk.
  • 4-10 METs (Moderate/Good): Climbing 1-2 flights of stairs (📌 1 flight $\approx$ 4 METs), running a short distance, heavy housework (e.g., scrubbing floors), moderate recreational activities (e.g., golf, dancing).
  • >10 METs (Excellent): Strenuous sports (e.g., swimming, singles tennis, football). Associated with ↓ risk.

⭐ Patients unable to achieve 4 METs of activity (e.g., cannot climb one flight of stairs or walk 4 blocks on level ground) have a significantly increased risk of postoperative cardiopulmonary complications, including MACE (Major Adverse Cardiac Events).

Key Cardiac Conditions - Red Flag Hearts

• Ischemic Heart Disease (IHD):
  • ⚠️ Recent MI (<1 month)/ACS: Postpone elective surgery. Very high risk.
  • Unstable Angina: Absolute contraindication for elective surgery.
  • PCI Stenting: Delay surgery (BMS: >30 days; DES: >6-12 months). Maintain DAPT.
• Heart Failure (HF):
  • ⚠️ Decompensated HF (NYHA Class IV): Postpone. Optimize first.
  • Severe LV dysfunction (LVEF <35%): ↑ perioperative risk.
• Valvular Heart Disease (VHD):
  • ⚠️ Severe Aortic Stenosis: AVA <$1.0 \text{ cm}^2$, mean gradient >40 mmHg. Symptomatic AS = very high risk.
  • Symptomatic Severe Mitral Stenosis: High risk; optimize/intervene.
• Arrhythmias & Conduction Defects:
  • High-grade AV block (Mobitz II, 3rd degree).
  • Symptomatic ventricular arrhythmias / sustained VT.
  • SVT with uncontrolled ventricular rate (>100 bpm at rest).
  • Pacemaker/ICD: Preoperative interrogation & management plan.

⭐ Critical Aortic Stenosis (symptomatic, or AVA <$1.0 \text{ cm}^2$ with mean gradient >40 mmHg) is a major predictor of perioperative cardiac MACE.

Investigations & Management - Test & Treat Plan

• ECG: All patients. Note Q, LVH, ST-TΔ, rhythm.
• Echocardiography: HF Sx, valvular dz, LVEF <40%.
• Stress Test (TMT/DSE): Poor METs (<4) & RCRI ≥1 for high/int-risk surgery.
• Management Strategy:
  • β-blockers: Continue. Start if ≥3 RCRI/CAD (vascular surg). HR 55-70 bpm.

    ⭐ Start days-weeks pre-op, not acutely.

  • Statins: Continue. Start: vascular surgery/CAD.
  • Aspirin: 2° prevention (stents): continue. Primary: stop 7d.
  • DAPT: BMS: delay 4-6w. DES: delay 6-12m. Urgent: ASA on.
  • Anticoagulants: Warfarin: stop 5d (INR <1.5), bridge high risk. NOACs: stop 1-5d.
  • Revascularization: Standard indications only.

High‑Yield Points - ⚡ Biggest Takeaways

• RCRI predicts MACE; assess for all surgical patients.
• <4 METs signifies poor functional capacity and ↑ cardiac risk.
• Active cardiac conditions (e.g., unstable angina, recent MI, severe valve disease, decompensated HF) need pre-op optimization.
• Continue beta-blockers if on them; consider for high-risk (≥3 RCRI) or known CAD.
• Continue aspirin for secondary prevention (stents/CAD); balance risks.
• DAPT duration post-stent dictates elective surgery timing.
• Severe symptomatic aortic stenosis is high-risk; consider pre-op intervention.