ICD-10-CM 2027
ICD-10 code for intrathoracic nonsyphilitic aneurysm
From the official ICD-10-CM alphabetic index entry “Aneurysm (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular) › intrathoracic (nonsyphilitic)”. Page updated September 29, 2026.
About coding intrathoracic nonsyphilitic aneurysm
The ICD-10-CM code for intrathoracic nonsyphilitic aneurysm is I71.20 (Thoracic aortic aneurysm, without rupture, unspecified). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I71.20.
Within I71.2, choose I71.20 (unspecified) only when documentation doesn't support a more specific option: aneurysm of the ascending aorta, without rupture (I71.21), aneurysm of the aortic arch, without rupture (I71.22) and aneurysm of the descending thoracic aorta, without rupture (I71.23).
Code first , if applicable: syphilitic aortic aneurysm (A52.01) and traumatic aortic aneurysm (S25.09, S35.09).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
More specific intrathoracic nonsyphilitic aneurysm codes (official index)
Common questions about intrathoracic nonsyphilitic aneurysm ICD-10 codes
What is the ICD-10 code for intrathoracic nonsyphilitic aneurysm?
- I71.20 — Thoracic aortic aneurysm, without rupture, unspecified. More specific codes apply when the documentation supports them: I71.10, A52.01.
What is the ICD-10 code for ruptured intrathoracic nonsyphilitic aneurysm?
- I71.10 — Thoracic aortic aneurysm, ruptured, unspecified.
What is the ICD-10 code for syphilitic intrathoracic nonsyphilitic aneurysm?
- A52.01 — Syphilitic aneurysm of aorta.
Is I71.20 billable?
- Yes. I71.20 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I71.20 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I71.20 as a principal diagnosis.
Is I71.20 a CC or MCC?
- No. I71.20 is neither a CC nor an MCC under MS-DRG v44.0.