Trauma Embolization — Principles & Approach

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Indications & Contraindications

Patient selection, injury grading, hemodynamic criteria

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Indications

Active arterial extravasation on CTA — contrast blush in arterial phase with expansion on delayed images
Contained vascular injury — pseudoaneurysm, arteriovenous fistula identified on cross-sectional imaging
Solid organ injury with contrast blush — liver, spleen, kidney injuries (AAST grade III–V) with evidence of active or contained hemorrhage
Pelvic fracture with arterial bleeding — first-line therapy per SIR guidelines when intrathoracic/intraabdominal sources excluded
Hemodynamically stable or stabilizing patients — responding to initial resuscitation; unstable patients not responding = OR
Persistent arterial hemorrhage despite surgical packing/intervention

Contraindications

Hemodynamic instability requiring emergent surgery — patient not responding to resuscitation; embolization takes ≥30 min and is not a substitute for damage-control surgery
Contrast allergy without adequate prep time (emergent setting may preclude steroid prep)
Grade V renal injury with shattered/devascularized kidney — typically requires surgical intervention
Relative: Severe coagulopathy — coils require functioning coagulation cascade; Gelfoam may be preferred
Relative: Major venous injury as primary bleeding source (not amenable to arterial embolization)

AAST Organ Injury Grading: For solid organ grading scales (spleen, liver, kidney), see the Body Trauma reference section — includes full AAST scale tables with CT criteria and management thresholds for each organ.

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Pre-Procedure Planning

ATLS, imaging, resuscitation, team communication

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ATLS & Imaging

Primary & secondary survey completed — ABCDE assessment prior to IR activation
CTA (arterial phase) — the roadmap; localizes bleeding source, identifies pseudoaneurysm/AVF/extravasation; sensitivity up to 80–85% for arterial injury
Delayed phase images helpful for localizing venous bleeding or slow extravasation
CTA may show: contrast extravasation, pseudoaneurysm, vessel cutoff, hemoperitoneum, sentinel clot sign
Consider proceeding directly to angiography if high clinical suspicion and hemodynamic instability precludes CT

Resuscitation & Labs

Massive transfusion protocol (MTP) activated if indicated — balanced resuscitation with 1:1:1 ratio (pRBC:FFP:platelets)
Permissive hypotension: target SBP ~90 mmHg; avoid aggressive crystalloid
2 large-bore IV access (14–16G) minimum
Type & screen / crossmatch — blood products available in IR suite
Labs: CBC, BMP, coagulation panel (PT/INR, fibrinogen), lactate, ABG
Foley catheter for urine output monitoring; NG tube if indicated

CTA reviewed. Bleeding source identified on arterial phase. Reformats reviewed for vascular anatomy and access planning.

Trauma surgery notified. Joint decision-making: IR embolization vs OR vs nonoperative management. Surgeon aware and available.

MTP activated if ongoing hemorrhage. Blood products in IR suite or immediately available.

Access planned. CFA access on side opposite to injury when possible. Groin assessed for hematoma or injury.

IR suite prepared. Anesthesia team notified (GA vs moderate sedation). Warming devices active. Hypothermia prevention measures in place.

Embolic agents stocked: Gelfoam, microcoils (multiple sizes), microcatheter system, 5F diagnostic catheters ready.

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Relevant Anatomy

Major vascular territories, organ supply, collateral pathways

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Major Vascular Territories

Aorta / great vessels — thoracic aortic injury (deceleration) at isthmus; endovascular repair (TEVAR) increasingly first-line for contained injuries
Liver (hepatic artery) — dual blood supply (hepatic artery + portal vein); hepatic artery embolization generally well-tolerated; right/left hepatic artery branches targeted selectively
Spleen (splenic artery) — goal is splenic preservation; proximal vs distal embolization; immune function preserved after embolization (unlike splenectomy)
Kidney (renal artery) — end-artery supply; superselective embolization critical to preserve parenchyma; segmental branches targeted
Pelvis (internal iliac artery) — anterior and posterior divisions; rich collateral network; nonselective embolization of internal iliac often tolerated
Extremities — paired vessel territories (anterior/posterior tibial, radial/ulnar); embolize only if collateral flow confirmed
Face / neck — external carotid branches (maxillary, facial); rich anastomoses but risk of cranial nerve injury

Key Collateral Pathways

Liver: portal venous supply sustains parenchyma after hepatic artery embolization; gastroduodenal artery collaterals
Pelvis: extensive collateral network between internal iliac divisions and across midline; lumbar, circumflex iliac, inferior mesenteric artery pathways
Pelvis: Corona mortis — anastomosis between inferior epigastric and obturator arteries; runs posterior to superior pubic ramus; vulnerable in pelvic fractures
Spleen: short gastric arteries provide limited collateral supply; proximal splenic embolization reduces perfusion pressure while preserving some flow
Kidney: minimal collateral supply — end-artery system; capsular collaterals insufficient to prevent infarction after main branch occlusion
Extremities: geniculate network around knee; palmar/plantar arches provide hand/foot collaterals

Pelvic Fracture & Arterial Injury Correlation

The pattern of pelvic fracture predicts the likely arterial injury. Anteroposterior compression injuries are associated with posterior division internal iliac artery injury; lateral compression injuries correlate with anterior division injury. Vertical shear fractures and combined mechanisms carry the highest risk of arterial hemorrhage. Always assess for bilateral injury and remember the corona mortis anastomosis.

4

Technique & Embolic Agents

Access, catheter selection, embolic agent principles

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1

Vascular Access

Common femoral artery (CFA) access — use the side opposite to the injury when possible (e.g., right CFA for left-sided pelvic injury). Ultrasound-guided access preferred, especially if groin hematoma or hypotension. Place 5F vascular sheath. Consider upsizing to 6F if stent-graft or larger devices anticipated.

2

Diagnostic Angiography

5F diagnostic catheter (Cobra, SOS Omni, pigtail) for initial aortogram or selective angiogram based on CTA findings. Abdominal aortogram if multifocal injury suspected. Selective catheterization of target vessel (celiac, SMA, renal, internal iliac) guided by CTA roadmap. Use DSA with adequate contrast volume and injection rate to opacify target territory.

3

Superselective Catheterization

Coaxial microcatheter (2.4–2.8F) advanced through diagnostic catheter to the target vessel as close to the injury as possible. Superselective positioning preserves maximal organ parenchyma. Use microwire (0.014–0.018") for navigation. Confirm position with selective angiogram before embolization.

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Embolization

Choose embolic agent based on injury type and target. Embolize as selectively as possible to preserve organ function. For pseudoaneurysms: coil embolization with “sandwich” technique (pack coils distal to injury, then proximal to exclude the pseudoaneurysm sac). For solid organ parenchymal bleeding: Gelfoam pledgets or slurry (temporary occlusion allows healing). Completion angiogram from diagnostic catheter to confirm hemostasis and assess for additional injuries.

5

Completion & Access Closure

Final angiogram to confirm no residual extravasation and no non-target embolization. Assess for additional injuries not seen on initial CTA. Sheath removal with manual compression or closure device. In coagulopathic patients, consider leaving sheath in place for potential re-access.

Embolic Agent Selection

Agent	Type	Best Use in Trauma
Gelfoam	Temporary	Solid organ trauma (spleen, liver, kidney) — inexpensive, reliable, works through microcatheter, allows vessel recanalization and organ healing
Coils	Permanent	Pseudoaneurysm, focal vessel injury, high-flow AVF — precise placement; require functioning coagulation; “sandwich” technique for PSA
Gelfoam + Coils	Combined	Coagulopathic patients — Gelfoam provides mechanical occlusion where coils alone may fail; sandwich technique
Glue (NBCA)	Permanent	Rarely used; high-flow situations where coils inadequate; operator experience required
Microspheres	Permanent	Generally avoided in trauma — risk of non-target embolization and end-organ infarction

Key Principles

Embolize as selectively as possible — preserve organ function and collateral pathways
Gelfoam is your workhorse — first-choice for solid organ trauma; temporary occlusion allows healing and vessel recanalization
Coagulopathy affects coil efficacy — coils rely on thrombus formation; in coagulopathic patients, supplement with Gelfoam for mechanical occlusion
Sandwich technique for pseudoaneurysm — coils distal, then proximal to exclude PSA and prevent backfill
Always perform completion angiogram — check for additional injuries, confirm hemostasis, assess non-target embolization

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Angiographic Landmarks & CTA Correlation

Recognizing injury patterns on angiography

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CTA Findings to Correlate

Active extravasation — high-density contrast outside vessel lumen; increases on delayed phase; correlates with active bleeding on angiogram
Pseudoaneurysm — smooth-walled contrast outpouching from artery; “yin-yang” sign on Doppler US; saccular outpouching on angiogram
Vessel truncation / cutoff — abrupt termination of contrast column; may indicate transection, thrombosis, or severe spasm
AV fistula — early venous filling on arterial phase CTA; on angiogram, rapid opacification of draining vein with arterialized waveform
Hemoperitoneum / sentinel clot sign — highest-density clot adjacent to bleeding source on CT helps localize injury

Angiographic Signs of Injury

Contrast extravasation — amorphous contrast blush outside vessel that persists and expands on delayed images
Pseudoaneurysm — contained saccular outpouching that fills and empties with cardiac cycle
Vessel irregularity / spasm — smooth narrowing (spasm) vs irregular narrowing (dissection/injury); spasm typically resolves with vasodilators
Vessel occlusion — complete absence of antegrade flow; may be thrombotic or from transection with retracted vessel ends
Arteriovenous fistula — rapid early venous filling with high-flow shunting; color bruit artifact on Doppler
Intimal flap — linear filling defect within vessel lumen suggesting dissection

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Troubleshooting

Occult bleeding, vasospasm, multifocal injury, coagulopathy

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Occult Bleeding

Cannot Identify Bleeding Source on Angiography Despite Positive CTA

This occurs in up to 15–20% of cases. Consider: (1) Empiric embolization of the vascular territory identified on CTA — embolize the branch supplying the area of extravasation seen on CT even if angiogram is negative. (2) Provocative angiography — administer intraarterial heparin (3,000–5,000 units), vasodilators (nitroglycerin 100–200 mcg), or low-dose tPA to unmask the bleeding site. (3) Vasospasm may be masking the injury — wait 10–15 min and repeat angiogram. (4) Bleeding may be intermittent; delayed imaging may reveal the source.

Vasospasm

Diffuse Vessel Narrowing Mimicking Injury or Obscuring Bleeding

Trauma patients are prone to vasospasm from hypovolemia, catecholamine surge, and direct vessel trauma. Vasospasm typically appears as smooth, symmetric narrowing. Administer intraarterial nitroglycerin (100–200 mcg) or verapamil (2.5–5 mg) to differentiate spasm from true injury. Wait 5–10 minutes and repeat angiogram. Spasm resolves; true injury does not. Avoid embolizing a spastic vessel — this can cause unnecessary organ infarction.

Multifocal Injuries

Multiple Bleeding Sites Requiring Prioritization

Triage based on: (1) Hemodynamic impact — treat the most life-threatening source first (usually the largest-volume extravasation on CTA). (2) Solid organ > pelvic > extremity in general priority. (3) Complete embolization of the primary source before addressing secondary sites. (4) If bilateral pelvic hemorrhage, consider nonselective bilateral internal iliac embolization with Gelfoam for rapid temporization. (5) Communicate with trauma team about prioritization and potential need for staged procedures.

Coagulopathy

Coagulopathic Patient — Embolic Agents Not Achieving Hemostasis

The “lethal triad” (hypothermia, acidosis, coagulopathy) impairs coil-dependent thrombosis. Strategies: (1) Use Gelfoam preferentially — provides mechanical occlusion independent of coagulation cascade. (2) Gelfoam + coil sandwich for larger vessels. (3) Coordinate with trauma team for correction of coagulopathy (FFP, cryoprecipitate, TXA, calcium). (4) Avoid over-relying on coils alone in coagulopathic patients. (5) Consider NBCA glue for high-flow situations where mechanical occlusion is needed immediately.

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Complications

Procedural risks and post-embolization sequelae

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Procedural Complications

Non-target embolization — embolic material migrating to unintended vascular territory; risk increased with Gelfoam slurry and coagulopathy; can cause bowel or organ infarction
Organ infarction — overly aggressive or non-selective embolization; splenic infarction (may still avoid splenectomy), hepatic infarction (usually tolerated due to portal supply), renal infarction (parenchymal loss)
Access site complications — hematoma, pseudoaneurysm, dissection at CFA puncture; higher risk in coagulopathic and hypotensive patients
Contrast-induced nephropathy — compounded by pre-existing hypovolemia/shock, prior CTA contrast load, and renal hypoperfusion
Vessel dissection or perforation — catheter/wire injury to already traumatized vessels

Post-Embolization Sequelae

Post-embolization syndrome — fever, pain, nausea, leukocytosis 24–72h post-procedure; common after splenic and hepatic embolization; supportive care
Rebleeding — Gelfoam is temporary (recanalization in 2–4 weeks); may require repeat embolization if clinically significant
Missed injuries — additional bleeding sources not identified on initial angiogram; require repeat CTA and possible second embolization
Splenic abscess / infarction — risk after proximal splenic embolization; monitor with clinical assessment and imaging
Hepatic abscess / biloma — may require delayed percutaneous drainage
Pelvic ischemia — rare but reported after bilateral internal iliac embolization; gluteal necrosis, bladder ischemia

8

Pearls & Pitfalls

High-yield tips for trauma embolization

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CTA is the roadmap. Always review the CTA before going to the angio suite. Identify the bleeding source, plan your catheter approach, and anticipate the vascular anatomy. Time spent reviewing CTA saves time on the table.

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Hemodynamically unstable = OR, not IR. Embolization takes at minimum 30 minutes. Patients not responding to resuscitation need damage-control surgery, not catheter-based intervention. IR is for patients who are stabilizing or stable.

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Gelfoam is your friend in solid organ trauma. It is inexpensive, readily available, easy to use through a microcatheter, provides reliable mechanical occlusion, and is temporary — allowing vessel recanalization and organ healing. It is the first-choice embolic agent in most trauma scenarios.

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Always check for additional injuries on the completion angiogram. Trauma patients frequently have multifocal injuries. A thorough completion angiogram from the diagnostic catheter position can identify bleeding not apparent on the initial selective run.

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Communication with the trauma team is key. IR is part of the resuscitation team, not an isolated consultant. Maintain ongoing communication about hemodynamic status, blood product needs, and the decision between IR and OR. Joint decision-making leads to better patient outcomes.

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Do not rely on coils alone in a coagulopathic patient. Coils depend on a functioning coagulation cascade to form occlusive thrombus. In patients with the lethal triad, coils alone may fail to achieve hemostasis. Always supplement with Gelfoam for mechanical occlusion.

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Do not mistake vasospasm for vessel transection. Spasm is common in trauma patients and can mimic vessel injury. Use vasodilators (intraarterial nitroglycerin) before committing to embolization of a spastic segment.

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Negative angiogram does not mean no injury. Up to 15–20% of CTA-positive patients may have negative initial angiograms due to vasospasm, intermittent bleeding, or low-flow states. Empiric embolization or provocative angiography may be necessary.

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Avoid microspheres in most trauma settings. Particles are difficult to control, risk non-target embolization, and cause end-organ infarction. Gelfoam pledgets provide similar temporary occlusion with better safety profile in the acute setting.

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References & Resources

Primary sources, guidelines, and related procedures

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Related Trauma Procedures

Splenic Trauma Embolization — proximal vs distal technique, splenic salvage
Hepatic Trauma Embolization — selective hepatic artery embolization, bile duct considerations
Renal Trauma Embolization — superselective technique for parenchymal preservation
Pelvic Trauma Embolization — internal iliac approach, fracture-guided targeting

Guidelines & Key References

EAST Practice Management Guidelines for hemorrhage in pelvic fracture
Western Trauma Association (WTA) algorithms for solid organ injury management
SIR Position Statement on Endovascular Intervention for Trauma (Padia SA et al. JVIR 2020)

Primary References

Kord A, Kuwahara JT, Rabiee B, Ray CE Jr. Basic Principles of Trauma Embolization. Semin Intervent Radiol. 2021;38(2):144–152.
Salazar GMM, Walker TG. Evaluation and Management of Acute Vascular Trauma. Tech Vasc Interventional Rad. 2009;12:102–116.
Velmahos GC, Toutouzas KG, Vassiliu P, et al. A prospective study on the safety and efficacy of angiographic embolization for pelvic and visceral injuries. J Trauma. 2002;53(2):303–308.
Padia SA, Ingraham CR, Moriarty JM, et al. Society of Interventional Radiology position statement on endovascular intervention for trauma. J Vasc Interv Radiol. 2020;31(3):363–369.e2.
Kozar RA, Crandall M, Shanmuganathan K, et al. Organ injury scaling 2018 update: spleen, liver, and kidney. J Trauma Acute Care Surg. 2018;85(6):1119–1122.
Lopera JE. Embolization in trauma: principles and techniques. Semin Intervent Radiol. 2010;27(1):14–28.