Safe and Effective Diagnosis of Microvascular Dysfunction in ANOCA: Insights from the NL-CFT Study

 1. Safe Diagnosis of ANOCA with Invasive Testing

• Invasive coronary functional testing can safely identify the cause of angina in patients with nonobstructive coronary artery disease (ANOCA).
• The testing was performed across 15 hospitals in the Netherlands, including both tertiary and nontertiary centers.
• The Netherlands Registry of Invasive Coronary Vasomotor Function Testing (NL-CFT) showed a high diagnostic yield and low complication rates.

2. Guidelines and Recommendations

• According to the 2024 European Society of Cardiology (ESC) guidelines, invasive coronary angiography with functional testing is recommended to:
  • Confirm or exclude obstructive coronary disease.
  • Diagnose ANOCA and identify treatable endotypes.
• In the US, invasive testing is considered reasonable for diagnosing persistent chest pain without coronary obstruction.

3. High Prevalence of Microvascular Dysfunction

• Around 50% of patients undergoing coronary angiography for angina show no coronary obstruction.
• Many patients, especially women, experience significant symptoms even without obstruction, affecting their physical function, mental health, and quality of life.
• Physicians are encouraged to investigate microvascular dysfunction instead of stopping at angiography.

4. Study Findings (NL-CFT Data)

• The study involved 1,207 patients (mean age: 60 years; 81% female).
• Testing included:
  • Intracoronary acetylcholine to provoke coronary spasm.
  • Measurements of coronary flow reserve and microvascular resistance using intravenous adenosine.
• Results:
  • 78% had abnormal test results:
    • 9% had coronary microvascular dysfunction (CMD).
    • 31% had isolated epicardial spasm.
    • 12% had epicardial spasm with CMD.
    • 17% had isolated microvascular spasm.
    • 9% had both microvascular spasm and CMD.

5. Safety and Complications

• The major complication rate was 0.9%, including:
  • Coronary dissections.
  • Ventricular tachycardia or ventricular fibrillation.
  • Hemodynamic instability.
• The complication rate was similar between tertiary and nontertiary centers.
• Atrial fibrillation requiring conversion occurred in 0.8% of patients.

6. Tailored Therapy and Treatment Recommendations

• Identification of specific ANOCA endotypes enables personalized treatment:
  • Calcium channel blockers for isolated vasospasm (Class I, Level A).
  • Nitrates to prevent recurrence (Class II, Level B).
  • Beta-blockers for microvascular angina (Class IIa, Level B).
  • Combination therapies for overlapping conditions (Class IIb, Level B).
• CorMicA study demonstrated improved symptoms and quality of life with tailored treatments.

7. Recommendations for Testing Centers

• Invasive functional testing should be integrated into centers performing angiography.
• No special expertise is required beyond standard angiographic procedures.

---

Take-Home Points:

• Invasive coronary functional testing is safe and provides a high diagnostic yield for patients with ANOCA.
• Many patients with angina have no obstructive coronary disease but may still suffer from microvascular dysfunction.
• Diagnosis through invasive testing can guide tailored treatments, improving both symptoms and quality of life.
• Complication rates are low, making this testing approach feasible in both experienced and less-experienced centers.
• Guidelines recommend combining therapies for patients with overlapping vasomotor dysfunctions.