ICD-10-CM > I00-I99 > I70-I79 > I71 > I71.2 I71.2 Thoracic aortic aneurysm, without rupture Non-Billable/Non-Specific Codes I71.20Thoracic aortic aneurysm, without rupture, unspecifiedI71.21Aneurysm of the ascending aorta, without ruptureI71.22Aneurysm of the aortic arch, without ruptureI71.23Aneurysm of the descending thoracic aorta, without rupture