Cardiology Coding Alert

One-to-one code crosswalks aren’t always what they seem.

Knowing the variety of synonyms for intermediate coronary syndrome is a good start for finding the proper code, but you’ll have some other elements to keep in mind when ICD-10 is implemented.

ICD-9-CM Code

• 411.1, Intermediate coronary syndrome 

ICD-10-CM Code

• I20.0, Unstable angina

Unstable angina is the name for unexpected chest pain that generally occurs when the patient is resting. A typical patient has coronary atherosclerosis that injures the vessel, leading to blood clots that reduce blood flow to the heart.

ICD-9 coding rules: ICD-9 uses the terminology “intermediate coronary syndrome” for the code. The long synonym list includes impending infarction, preinfarction angina, preinfarction syndrome, and unstable angina.

You should not use 411.1 for angina (pectoris). An Excludes note points you to 413.9 (Other and unspecified angina pectoris) for that diagnosis. The Excludes note also lists decubitus, pointing you to 413.0 (Angina decubitus).

ICD-10 changes: The most obvious change between ICD-9 and ICD-10 for this diagnosis is the terminology chosen for the official descriptor. ICD-10 chooses “unstable angina,” a term ICD-9 listed as a synonym. ICD-10 lists the ICD-9 term “intermediate coronary syndrome” as a synonym, along with accelerated angina, crescendo angina, de novo effort angina, preinfarction syndrome, and worsening effort angina.

Documentation: Documenting unstable angina for I20.0 may seem fairly straightforward under ICD-10, but you may also need details on atherosclerosis to choose the most appropriate codes, as the next section explains.

Coder tips: ICD-10 offers combination codes for unstable angina and atherosclerosis, so if the cardiologist documents both, you should choose from the following codes (bold added) instead of reporting I20.0:

• I25.110, Atherosclerotic heart disease of native coronary artery with unstable angina pectoris

• I25.700, Atherosclerosis of coronary artery bypass graft(s), unspecified, with unstable angina pectoris

• I25.710, Atherosclerosis of autologous vein coronary artery bypass graft(s) with unstable angina pectoris

• I25.720, Atherosclerosis of autologous artery coronary artery bypass graft(s) with unstable angina pectoris

• I25.730, Atherosclerosis of nonautologous biological coronary artery bypass graft(s) with unstable angina pectoris

• I25.750, Atherosclerosis of native coronary artery of transplanted heart with unstable angina

• I25.760, Atherosclerosis of bypass graft of coronary artery of transplanted heart with unstable angina

• I25.790, Atherosclerosis of other coronary artery bypass graft(s) with unstable angina pectoris.

Remember: CMS has announced Oct. 1, 2015, as the compliance date for ICD-10. When ICD-10-CM goes into effect, you should apply the code set and official guidelines in effect for the date of service reported. Learn more at www.cms.gov/ICD10/ and www.cdc.gov/nchs/icd/icd10cm.htm#10update.