ICD-10 Code I71.21 – Aneurysm of the ascending aorta, without rupture (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I71.21 – Aneurysm of the ascending aorta, without rupture
What it is
I71.21 identifies a localized enlargement of the ascending aorta that has not ruptured. Use it when documentation states an ascending aortic aneurysm without mention of dissection or rupture.
Clinical signs
Clinical features vary; refer to documentation. Many patients are asymptomatic, and the finding may come from imaging that shows dilation of the ascending aorta.
When to use this code
Use this code when the provider documents an aneurysm limited to the ascending aorta and explicitly notes no rupture. It also fits follow-up visits for a known ascending aortic aneurysm when the condition remains unruptured.
Check documentation if the record mentions dissection, rupture, or a different aortic segment. Code the most specific aortic diagnosis supported by the note or imaging report.
Do not use for
Do not use I71.21 for ruptured aneurysm, aortic dissection, or aneurysm in another aortic location. If the documentation is unclear, check documentation.
Coding tip
Confirm the exact aortic segment and whether rupture is excluded before assigning I71.21.