ICD-10 Code I71.23 – Aneurysm of the descending thoracic aorta, without rupture (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I71.23 – Aneurysm of the descending thoracic aorta, without rupture
What it is
This code identifies a localized dilation of the descending thoracic aorta that has not ruptured. Use it when documentation names a descending thoracic aortic aneurysm and does not describe dissection or rupture.
Clinical signs
Many cases are found on imaging and may be asymptomatic. When present, features can include chest or back discomfort, a pulsatile mediastinal finding, or evidence of aneurysmal enlargement on CT, MRI, or echocardiography; clinical features vary, refer to documentation.
When to use this code
Use I71.23 when the provider documents an aneurysm specifically involving the descending thoracic aorta and there is no mention of rupture. It also fits follow-up visits, surveillance imaging, or preoperative evaluation for a known, unrepaired aneurysm. If the record is unclear about location or complication status, check documentation.
Do not use for
Do not use this code for thoracic aortic dissection, ruptured aneurysm, or aneurysms in other aortic segments. If the documentation only says “thoracic aortic aneurysm” without specifying the descending portion, check documentation.
Coding tip
Confirm both the anatomic site and the absence of rupture before assigning I71.23.