ICD-10 Code I20.81 – Angina pectoris with coronary microvascular dysfunction (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I20.81 – Angina pectoris with coronary microvascular dysfunction
What it is
This code identifies angina caused by coronary microvascular dysfunction, where the small coronary vessels do not supply enough blood flow. Use it when documentation links angina symptoms to microvascular disease rather than obstructive coronary artery disease.
Clinical signs
Patients typically have angina-type chest discomfort, often with exertional or stress-related symptoms. Clinical features vary; refer to documentation for evidence of microvascular dysfunction, such as a provider-documented diagnosis or testing consistent with impaired microvascular perfusion.
When to use this code
Use this code when the provider specifically documents angina pectoris with coronary microvascular dysfunction. It is appropriate when the record shows chest pain or angina attributed to microvascular disease and not explained by a larger-vessel coronary blockage. Check documentation if the cause is unclear.
Do not use for
Do not use this code for unspecified chest pain, stable angina without microvascular dysfunction, or angina due to obstructive coronary artery disease. If the record does not clearly link the angina to microvascular dysfunction, check documentation.
Coding tip
Code I20.81 only when the diagnosis is explicitly stated or clearly supported in the chart.