I71.012

HCC Category Mapping

What This Code Means

A tear in the inner lining of the main artery that carries blood down through the chest, causing blood to flow between the layers of the artery wall. This is a serious condition that requires immediate medical attention.

Coding Tips

• •Verify the specific location is documented as descending thoracic aorta (not ascending or abdominal) before assigning this code
• •This code may require additional codes for complications (rupture, thrombosis) or associated conditions; review the complete clinical documentation for any secondary diagnoses

Clinical Significance

Dissection of the descending thoracic aorta is a life-threatening emergency where a tear in the aortic intima allows blood to enter the vessel wall, creating a false lumen that can propagate and compromise branch vessel perfusion. Aortic dissection carries high mortality without prompt diagnosis and treatment, and survivors require lifelong surveillance for aneurysm development, re-dissection, and end-organ damage. This is a high-acuity diagnosis that significantly impacts risk adjustment, reflecting the intensive acute care and ongoing management these patients require.

Documentation Requirements

• ✓Aortic dissection explicitly documented at the descending thoracic aorta
• ✓Classification type documented when possible (Stanford Type A or B, DeBakey I, II, or III)
• ✓Imaging confirmation (CT angiography, MRI, transesophageal echocardiography, or surgical findings)
• ✓Acute vs. chronic status clarified — this code may be used for both, but clinical context should be clear
• ✓Extent of dissection (which segments of aorta are involved)
• ✓Complications documented (malperfusion syndrome, aortic regurgitation, pericardial effusion, end-organ ischemia)
• ✓Current management plan (medical, endovascular, or open surgical repair)

Commonly Confused Codes