ICD-10-CM 2027
ICD-10 code for mitral deformity
From the official ICD-10-CM alphabetic index entry “Deformity › mitral (leaflets) (valve)”. Page updated September 29, 2026.
About coding mitral deformity
The ICD-10-CM code for mitral deformity is I05.8 (Other rheumatic mitral valve diseases). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I05.8.
Within I05, choose I05.8 (Other rheumatic mitral valve diseases) only when documentation doesn't support a more specific option: rheumatic mitral stenosis (I05.0), rheumatic mitral insufficiency (I05.1), rheumatic mitral stenosis with insufficiency (I05.2) and rheumatic mitral valve disease, unspecified (I05.9).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 306 (Cardiac Congenital and Valvular Disorders with MCC, relative weight 1.546) and DRG 307 (Cardiac Congenital and Valvular Disorders without MCC, relative weight 0.9148), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific mitral deformity codes (official index)
Common questions about mitral deformity ICD-10 codes
What is the ICD-10 code for mitral deformity?
- I05.8 — Other rheumatic mitral valve diseases. More specific codes apply when the documentation supports them: Q23.2, Q23.2.
What is the ICD-10 code for parachute mitral deformity?
- Q23.2 — Congenital mitral stenosis.
Is I05.8 billable?
- Yes. I05.8 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I05.8 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I05.8 as a principal diagnosis.
Is I05.8 a CC or MCC?
- No. I05.8 is neither a CC nor an MCC under MS-DRG v44.0.