dissection

DEFINITION of dissection

Vascular dissection is a life-threatening condition in which a longitudinal tear occurs in the tunica intima (innermost layer) of an arterial wall, allowing blood to track between the intima and the tunica media, or between the media and adventitia, forming a false lumen parallel to the true lumen. As blood fills this false channel, it can compress the true lumen (causing ischemia), propagate proximally or distally, rupture through the outer wall (causing hemorrhage or tamponade), or occlude branch vessels. Dissections can be spontaneous (from hypertension, connective tissue disease, or fibromuscular dysplasia), traumatic (blunt/penetrating injury), or iatrogenic (from catheterization). The aorta is the most commonly affected vessel, though dissections can occur in carotid, vertebral, coronary, renal, iliac, and cerebral arteries. In surgical contexts, “dissection” also refers to the deliberate technique of separating tissue planes — but in the diagnostic/coding context, it refers exclusively to the pathological vessel wall injury described above.

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ETYMOLOGY of dissection

latin

Component	Origin	Meaning
dis-	Latin dis-	Apart, asunder, away
-section	Latin secare (to cut), sectio	A cutting; a division

Literally: “a cutting apart” — originally describing both the surgical act of separating tissues and the pathological splitting of vessel wall layers. In vascular pathology, it specifically denotes the spontaneous or traumatic separation of arterial wall layers.

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🔀 ALIASES / ALTERNATE TERMS

• Aortic dissection (most common clinical usage)
• Dissecting aneurysm (older/historical term — a misnomer, as dissection ≠ true aneurysm)
• Dissecting hematoma (emphasizes the blood-filled false lumen)
• Stanford Type A dissection — involves the ascending aorta (surgical emergency)
• Stanford Type B dissection — does not involve the ascending aorta (often managed medically)
• DeBakey Type I — ascending + descending aorta involved
• DeBakey Type II — ascending aorta only
• DeBakey Type III — descending aorta only (IIIa = thoracic; IIIb = thoracoabdominal)
• Spontaneous coronary artery dissection (SCAD) — distinct entity, common in young women
• Cervical artery dissection — carotid or vertebral; often cause of stroke in young adults
• Traumatic aortic injury (TAI) — dissection from blunt chest trauma

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🔗 RELATED TERMS

• Intimal tear — the initiating event
• False lumen — the blood-filled channel created within the wall
• True lumen — the original vessel channel, often compressed
• Aortic aneurysm — different pathology (dilation without wall tear); may coexist
• Intramural hematoma (IMH) — related entity; blood within wall without intimal tear
• Penetrating aortic ulcer (PAU) — atherosclerotic ulcer that can progress to dissection
• Tamponade — life-threatening complication of Type A dissection
• Hemothorax / Hemoperitoneum — rupture complications
• Malperfusion syndrome — branch vessel occlusion from propagating false lumen
• Fibromuscular dysplasia (FMD) — predisposing condition, especially for cervical dissection
• Marfan syndrome / Ehlers-Danlos syndrome — connective tissue diseases predisposing to dissection
• TEVAR — Thoracic Endovascular Aortic Repair (treatment for Type B)
• Open aortic repair — surgical treatment for Type A

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🩻 CODING CORNER

🏥 ICD-10-CM CODES

Aortic Dissection (Category I71.0x)

Code	Description
I71.00	Dissection of unspecified site of aorta
I71.010	Dissection of ascending aorta (Stanford Type A / DeBakey Type II)
I71.011	Dissection of aortic arch (Stanford Type A / DeBakey Type I)
I71.012	Dissection of descending thoracic aorta (Stanford Type B / DeBakey Type III)
I71.019	Dissection of thoracic aorta, unspecified
I71.02	Dissection of abdominal aorta
I71.03	Dissection of thoracoabdominal aorta (DeBakey Type I / IIIb)

Cervical / Precerebral Artery Dissection (Category I77.7x)

Code	Description
I77.70	Dissection of unspecified artery
I77.71	Dissection of carotid artery
I77.72	Dissection of iliac artery
I77.73	Dissection of renal artery
I77.74	Dissection of vertebral artery
I77.75	Dissection of other precerebral arteries
I77.76	Dissection of artery of upper extremity
I77.77	Dissection of artery of lower extremity
I77.79	Dissection of other specified artery

Cerebral & Coronary Dissection

Code	Description
I67.0	Dissection of cerebral arteries, nonruptured
I25.42	Coronary artery dissection (includes SCAD)

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🔧 COMMON CPT CODES (Dissection-Related Procedures & Imaging)

Aortic Repair — Open

CPT Code	Description
33860	Ascending aorta graft, with cardiopulmonary bypass (Type A repair)
33870	Transverse aortic arch graft, with cardiopulmonary bypass
33875	Descending thoracic aorta graft (Type B open repair)
35082	Repair of ruptured aneurysm, abdominal aorta

Aortic Repair — Endovascular (TEVAR/EVAR)

CPT Code	Description
33880	TEVAR, descending thoracic aorta (covering left subclavian)
33881	TEVAR, descending thoracic aorta (not covering left subclavian)
33883	Placement of proximal extension prosthesis for TEVAR
33884	Each additional proximal extension for TEVAR
34701	EVAR, infrarenal abdominal aorta

Carotid / Vertebral Dissection Procedures

CPT Code	Description
35301	Carotid thromboendarterectomy (may be needed post-dissection)
37215	Carotid stenting with embolic protection
37216	Carotid stenting without embolic protection

Diagnostic Imaging

CPT Code	Description
71275	CT angiography, thoracic aorta
74175	CT angiography, abdominal aorta
75956	Endovascular repair of descending thoracic aorta (radiological supervision)
93567	Injection for aortography (during cardiac cath)
70498	CT angiography, neck (carotid/vertebral dissection)
70553	MRI brain with and without contrast
70549	MRA neck with and without contrast

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⚠️ Coding Note: Aortic dissection codes under I71.0x are MCC (Major Complication/Comorbidity) and are among the highest-weighted diagnoses in MS-DRG grouping. Always code to the most specific site — “ascending,” “arch,” “descending thoracic,” “abdominal,” or “thoracoabdominal” — using operative/imaging reports. The Stanford and DeBakey classifications are not directly reflected in ICD-10 code titles but map as shown above. For SCAD (spontaneous coronary artery dissection), use I25.42 — it is distinct from atherosclerotic coronary artery disease and should not be coded with I25.1x codes. Cervical artery dissection (I77.71 carotid, I77.74 vertebral) is a common cause of stroke/TIA in younger patients — always check for a concurrent I63.x or G45.x code when documented.

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DERIVATIONS of dissection

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Med roots Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms