I71.23

Billable

Aneurysm of the descending thoracic aorta, without rupture

HCC Category Mapping

V24HCC 108 — Vascular Disease

0.297

ESRDHCC 108 — Vascular Disease

0.000

What This Code Means

A weakened, bulging area in the descending thoracic aorta (the lower portion of the main artery in the chest) that has not burst or ruptured.

Coding Tips

•Ensure documentation clearly specifies 'descending thoracic' to differentiate from abdominal aortic aneurysms
•Monitor for progression and document any imaging findings regarding size and stability

Clinical Significance

Thoracic aortic aneurysm without rupture (descending thoracic aorta) represents pathological dilation of the thoracic aorta that has not yet ruptured but carries ongoing risk of rupture, dissection, and compression of adjacent structures. Risk of rupture increases with aneurysm size, and patients require lifelong imaging surveillance and blood pressure management. While less acute than a ruptured aneurysm, this is a chronic condition with significant resource utilization for serial imaging, specialist follow-up, and potential elective surgical repair.

Documentation Requirements

✓Thoracic aortic aneurysm documented — location: descending thoracic aorta
✓Non-ruptured status confirmed (absence of rupture, contained rupture explicitly excluded)
✓Aneurysm size documented (critical for determining surveillance interval and surgical threshold)
✓Imaging modality and findings (CT angiography, MRI, echocardiography)
✓Growth rate compared to prior imaging when available
✓Current management plan (blood pressure control targets, surveillance imaging schedule, surgical repair threshold)
✓Associated conditions documented (bicuspid aortic valve, connective tissue disorders such as Marfan syndrome, aortic regurgitation)

Commonly Confused Codes

I71.10-I71.13 — Thoracic aortic aneurysm WITH rupture (critical distinction — ruptured carries much higher acuity and different HCC mapping)I71.00-I71.03 — Aortic dissection (different pathology — intimal tear vs. aneurysmal dilation)I71.40-I71.41 — Abdominal aortic aneurysm without rupture (different anatomical location)I77.810-I77.812 — Aortic ectasia (mild dilation that does not meet aneurysm size criteria — typically less than 1.5 times normal diameter)