I20.0 Unstable angina

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Accelerated angina
• Crescendo angina
• De novo effort angina
• Intermediate coronary syndrome
• Preinfarction syndrome
• Worsening effort angina

Applies from I20 Angina pectoris

Excludes1 (never code together)

• angina pectoris with atherosclerotic heart disease of native coronary arteries (I25.1-)
• atherosclerosis of coronary artery bypass graft(s) and coronary artery of transplanted heart with angina pectoris (I25.7-)
• postinfarction angina (I23.7)

Use additional code

• code to identify:
• exposure to environmental tobacco smoke (Z77.22)
• history of tobacco dependence (Z87.891)
• occupational exposure to environmental tobacco smoke (Z57.31)
• tobacco dependence (F17.-)
• tobacco use (Z72.0)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 229 — Unstable Angina and Other Acute Ischemic Heart Disease
• CMS-HCC V22: HCC 87 — Unstable Angina and Other Acute Ischemic Heart Disease
• RxHCC V08: HCC 188 — Coronary Artery Disease
• ESRD V24: HCC 87

MS-DRG index

Defines the logic of DRG(s) 311 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 411.1 Intermediate coronary syndrome (approximate)

Code annotations containing back-references to I20.0

Back-references to I20.0

• Type 1 Excludes: I25.110 Atherosclerotic heart disease of native coronary artery with unstable angina pectoris ("unstable angina without atherosclerotic heart disease (I20.0)")
• Type 1 Excludes: I25.700 Atherosclerosis of coronary artery bypass graft(s), unspecified, with unstable angina pectoris ("unstable angina pectoris without atherosclerosis of coronary artery bypass graft (I20.0)")
• Type 1 Excludes: I25.710 Atherosclerosis of autologous vein coronary artery bypass graft(s) with unstable angina pectoris ("unstable angina without atherosclerosis of autologous vein coronary artery bypass graft(s) (I20.0)")
• Type 1 Excludes: I25.720 Atherosclerosis of autologous artery coronary artery bypass graft(s) with unstable angina pectoris ("unstable angina without atherosclerosis of autologous artery coronary artery bypass graft(s) (I20.0)")
• Type 1 Excludes: I25.730 Atherosclerosis of nonautologous biological coronary artery bypass graft(s) with unstable angina pectoris ("unstable angina without atherosclerosis of nonautologous biological coronary artery bypass graft(s) (I20.0)")
• Type 1 Excludes: I25.790 Atherosclerosis of other coronary artery bypass graft(s) with unstable angina pectoris ("unstable angina without atherosclerosis of other coronary artery bypass graft(s) (I20.0)")

Back-references to I20

• Type 1 Excludes: I24 Other acute ischemic heart diseases ("angina pectoris (I20.-)")

Diagnosis Index entries for I20.0

• Angina (attack) (cardiac) (chest) (heart) (pectoris) (syndrome) (vasomotor) › unstable
• Impending › coronary syndrome
• Impending › myocardial infarction
• Infarct, infarction › impending (myocardium)
• Syndrome › coronary › insufficiency or intermediate
• Syndrome › impending coronary
• Syndrome › intermediate coronary (artery)
• Syndrome › preinfarction

Nearby codes

• I20 Angina pectoris
• I20.0 Unstable angina (this code)
• I20.1 Angina pectoris with documented spasm
• I20.2 Refractory angina pectoris
• I20.8 Other forms of angina pectoris
• I20.81 Angina pectoris with coronary microvascular dysfunction
• I20.89 Other forms of angina pectoris