I21.A9: Other myocardial infarction type

Clinical notes

Code also

Two codes may be needed to fully describe a condition, but unlike Code First/Use Additional Code, the sequencing order is not mandated by convention.

complication, if known and applicable, such as:
(acute) stent occlusion (T82.897-)
(acute) stent stenosis (T82.855-)
(acute) stent thrombosis (T82.867-)
cardiac arrest due to underlying cardiac condition (I46.2)
complication of percutaneous coronary intervention (PCI) (I97.89)
occlusion of coronary artery bypass graft (T82.218-)

Code first

This code represents a manifestation of an underlying disease. Coding convention requires the underlying (etiology) code to be sequenced first, with this code listed second.

, if applicable, postprocedural myocardial infarction following cardiac surgery (I97.190), or postprocedural myocardial infarction during cardiac surgery (I97.790)

Also known as

Alternate wording, synonyms, or specific conditions that fall under this code, listed to help confirm you've picked the right one.

Myocardial infarction associated with revascularization procedure
Myocardial infarction type 3
Myocardial infarction type 4a
Myocardial infarction type 4b
Myocardial infarction type 4c
Myocardial infarction type 5

Documentation support

General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.

•This code represents a manifestation. Documentation should identify the underlying condition, which must be coded first.
•As a general rule, code to the highest level of specificity supported by the documentation in the medical record.

Related codes in this category

I21.A1Myocardial infarction type 2
I21.A9Other myocardial infarction type

ICD-9-CM equivalent

Informational only — GEM mappings are approximate, not guaranteed one-to-one equivalents. Verify before use in billing.

41090Approximate match
41091Approximate match
41092Approximate match

View full ICD-10 → ICD-9 crosswalk →

Associated MS-DRGs

I21.A9 can serve as the principal diagnosis for these Medicare Severity Diagnosis-Related Groups.

Informational only — actual DRG assignment also depends on procedures, complications/comorbidities (CC/MCC), discharge status, and payer-specific rules not reflected here.