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Indications & Contraindications
AAST grading, patient selection, proximal vs distal debate
Indications
- Blunt splenic injury AAST grade III–V with contrast blush or pseudoaneurysm on CTA in hemodynamically stable or stabilizing patients
- Grade I–III with direct vascular injury — contrast extravasation, pseudoaneurysm (PSA), or arteriovenous fistula (AVF) on CTA regardless of grade
- Grade IV–V injuries regardless of direct signs of vascular injury — referred for angiography per WTA algorithm
- Grade I–II without vascular injury — typically observation only
- Proximal vs distal embolization: proximal preferred for multifocal/diffuse injury; distal (superselective) for focal extravasation or PSA; combined for AAST IV–V
Contraindications
- Hemodynamic instability refractory to resuscitation — patient requires emergent splenectomy
- Peritonitis / signs of hollow viscus injury requiring laparotomy
- Grade V shattered spleen without residual vascularization
- Uncorrectable coagulopathy
- Relative: severe contrast allergy (prep with steroids if time permits)
- Relative: inappropriate triage to nonoperative management (up to 40% of major complications from SAE occur in inappropriately triaged patients)
AAST Splenic Injury Grading
| Grade | Hematoma | Laceration / Vascular |
|---|---|---|
| I | Subcapsular, <10% surface area | Capsular tear, <1 cm depth |
| II | Subcapsular 10–50%; intraparenchymal <5 cm | 1–3 cm depth, no trabecular vessel |
| III | Subcapsular >50% or expanding; ruptured | >3 cm depth or involving trabecular vessels |
| IV | — | Segmental/hilar vessel injury, >25% devascularization |
| V | — | Shattered spleen or hilar vascular injury with complete devascularization |
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Pre-Procedure Planning
CTA review, labs, trauma team coordination, MTP
Imaging & Labs
- CTA abdomen/pelvis: review AAST grade, identify contrast blush, PSA, AVF, extent of hemoperitoneum, and associated injuries
- Arterial phase improves sensitivity for active splenic hemorrhage — request if not already obtained
- Evaluate splenic artery origin (celiac trunk vs aortic origin variant ~8%) and degree of tortuosity
- Labs: CBC (serial H/H), PT/INR, PTT, fibrinogen, type & screen / crossmatch
- Lactate, base deficit — markers of resuscitation adequacy
Coordination & Preparation
- Communicate with trauma surgery — confirm patient appropriate for nonoperative management; OR on standby for potential splenectomy
- Activate massive transfusion protocol (MTP) if needed — pRBC, FFP, platelets available in IR suite
- Ensure large-bore IV access ×2, arterial line if hemodynamically borderline
- Consent: risks of splenic infarction, rebleeding, abscess, need for splenectomy, contrast reaction
CTA reviewed. AAST grade assigned, vascular injury identified, splenic artery anatomy assessed for tortuosity and variant origins.
Trauma surgery notified. Nonoperative management confirmed; OR on standby for conversion to splenectomy if needed.
Blood products available. Type & crossmatch sent; MTP activated or on standby; pRBC in IR suite.
Coagulopathy addressed. INR, platelets, fibrinogen checked; correct with FFP, platelets, cryoprecipitate as needed.
Access & monitoring. Large-bore IV ×2, arterial line if borderline, Foley catheter for UOP monitoring.
Consent obtained. Risks: splenic infarction, rebleeding, abscess, splenectomy, OPSI, pancreatitis, contrast reaction.
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Relevant Anatomy
Splenic artery, branches, collateral pathways
Splenic Artery
- Origin: celiac trunk (most common), arising from abdominal aorta at ~T12 level; variant origins include directly off aorta (~8%) or SMA (<1%)
- Course: tortuous path along the superior border of the pancreas toward the splenic hilum
- Dorsal pancreatic artery: first major branch, arises within first few cm of splenic artery origin; connects to transverse pancreatic artery — critical collateral pathway
- Greater pancreatic artery (pancreatica magna): arises more distally; its connection to the dorsal pancreatic artery via the transverse pancreatic artery is the key collateral for proximal embolization
- Terminal branches: polar arteries (superior and inferior) divide into segmental branches at the hilum
Collateral Supply & End-Organ Considerations
▶ Splenic artery anatomy — dorsal pancreatic & pancreatica magna
Splenic artery anatomy: dorsal pancreatic artery (red) and pancreatica magna (purple) — preserve these pancreatic branches when performing distal superselective splenic embolization.
- Short gastric arteries: connect splenic artery to left gastric artery; major collateral pathway maintaining splenic perfusion after proximal embolization
- Left gastroepiploic artery: distal branch of splenic artery; anastomoses with right gastroepiploic artery (from GDA) along the greater curvature of the stomach
- Dorsal pancreatic–transverse pancreatic–greater pancreatic pathway: maintains perfusion distal to proximal coil/plug placement
- Spleen is effectively an end-organ with limited intrinsic collateral — distal embolization carries higher infarction risk than proximal
- Proximal embolization reduces perfusion pressure while preserving splenic function via collateral pathways
Ideal Site for Proximal Embolization
The midsplenic artery, distal to the origin of the dorsal pancreatic artery but proximal to the origin of the greater pancreatic artery, is the ideal location for proximal coil or plug placement. This preserves the dorsal pancreatic–transverse pancreatic–greater pancreatic artery collateral pathway, which along with the short gastric arteries and gastroepiploic arcade, maintains adequate splenic parenchymal perfusion at reduced systolic pressure, allowing the spleen to heal.
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Technique
Proximal, distal, and combined embolization approaches
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Arterial Access
Right common femoral artery access using micropuncture set under ultrasound guidance. Place 5-Fr vascular sheath. Consider left CFA or transradial approach if right CFA unavailable (arterial line, pelvic binder).
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Celiac Trunk Selection & Angiography
Advance 5-Fr catheter (Cobra 2, Simmons 1, or SOS Omni) to the celiac trunk. Perform celiac angiography at 5 cc/sec for 25 cc total to evaluate splenic artery anatomy, identify contrast extravasation, PSA, or AVF, and map branch anatomy including the dorsal pancreatic and greater pancreatic arteries.
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Selective Splenic Artery Catheterization
Advance into the splenic artery. For tortuous vessels, a microcatheter (2.4–2.8 Fr) and microwire may be required. Perform selective splenic arteriography to further delineate injury, identify all sites of active hemorrhage, and plan embolization strategy.
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Strategy Decision: Proximal vs Distal vs Combined
Proximal SAE (pSAE): Preferred for multifocal injury, grade III–V without focal bleed, or as a rapid technique. Deploy coils or vascular plug in the midsplenic artery (distal to dorsal pancreatic artery, proximal to greater pancreatic artery). Reduces perfusion pressure while preserving splenic function via collaterals. — Distal SAE (dSAE): Preferred for focal extravasation or single PSA. Advance microcatheter to the bleeding branch, embolize with coils, Gelfoam, or particles. Endpoint is stasis in the target vessel. — Combined pSAE + dSAE: Consider for AAST grade IV–V injuries. Superselective embolization of focal bleed(s) followed by proximal coil/plug to reduce overall perfusion pressure.
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Proximal Embolization Technique
Deploy endovascular coils (pushable or detachable) or vascular plug in the midsplenic artery. Pack coils tightly for high-flow vessel. A single vascular plug may be sufficient but requires selective catheterization with larger delivery system. If stasis not achieved in reasonable time, supplement with gelatin sponge slurry. Confirm placement distal to dorsal pancreatic artery to preserve collateral pathway.
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Distal / Superselective Embolization Technique
Advance microcatheter (2.4–2.8 Fr) coaxially to the bleeding branch(es). Embolize using microcoils, Gelfoam pledgets/slurry, particles, or N-butyl cyanoacrylate (NBCA). Endpoint: stasis within the target vessel(s). Perform post-embolization arteriography to confirm cessation of extravasation.
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Completion Angiography & Closure
Perform completion celiac/splenic arteriography to confirm: (1) no residual extravasation, (2) adequate flow reduction (proximal), (3) collateral supply via short gastric and gastroepiploic arteries is maintained. Remove catheter and sheath. Manual compression or closure device at femoral access site.
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Landmarks & Key Findings
Angiographic landmarks and identification of injury
Angiographic Landmarks
- Celiac trunk: first major anterior branch of abdominal aorta at ~T12/L1; trifurcates into left gastric, common hepatic, and splenic arteries
- Splenic artery origin: typically leftward from celiac trunk; identify tortuosity early for catheter selection
- Dorsal pancreatic artery: first major branch — marks the proximal boundary for safe coil placement
- Greater pancreatic artery: marks the distal boundary — coils placed between these two landmarks
- Short gastric arteries: small branches to gastric fundus; key collaterals visible on post-embolization runs
Signs of Vascular Injury on Angiography
- Active extravasation: contrast blush that persists and increases in density on subsequent phases; irregular, amorphous contrast pooling outside the vascular lumen
- Pseudoaneurysm (PSA): focal, well-circumscribed contrast collection that fills and empties with arterial phase; contained rupture
- Arteriovenous fistula (AVF): early opacification of splenic or portal vein during arterial phase
- Vessel truncation / irregularity: abrupt cutoff or spasm of intrasplenic branches suggesting parenchymal disruption
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Troubleshooting
Tortuous anatomy, persistent bleeding, technical challenges
Tortuous Splenic Artery
Unable to Advance Catheter to Target
Extremely common in elderly patients. Switch to coaxial microcatheter system (2.4–2.8 Fr) over a shapeable microwire. Consider using a guide catheter or long sheath for additional support. Simmons or SOS catheter may provide better purchase in the celiac trunk. If tortuosity is extreme and proximal embolization is planned, deploy coils where catheter reaches in the midsplenic artery.
Multiple Bleeding Sites
Diffuse Extravasation From Multiple Branches
Switch strategy to combined approach: perform proximal embolization (coils/plug in midsplenic artery) to reduce overall perfusion pressure, then superselectively embolize the most active bleeding sites. If too many sites to individually treat, proximal embolization alone may suffice as it reduces pressure to all branches.
Persistent Bleeding Post-Embolization
Ongoing Extravasation After Initial Embolization
Re-evaluate with repeat angiography. Check for collateral supply feeding the bleeding site (short gastric, gastroepiploic). Consider additional coiling of collateral feeders. If persistent despite repeat embolization, communicate with trauma surgery for conversion to splenectomy. Do not delay surgical intervention for uncontrolled hemorrhage.
Splenic Artery Spasm
Small-Caliber or Spastic Splenic Artery
Vasospasm can mimic small vessel caliber. Administer intra-arterial nitroglycerin 100–200 mcg to relieve spasm. Wait 1–2 minutes and re-image. Use hydrophilic microcatheter and wire to navigate. Avoid excessive catheter manipulation which worsens spasm. If true small caliber, vascular plug may not be deliverable — use coils via microcatheter.
Coil Migration
Coil Pack Migrating in High-Flow Splenic Artery
High-flow environment of the splenic artery can lead to coil migration. Anchor first coil securely; slightly oversize coils relative to vessel diameter (1–2 mm larger). Deploy multiple coils to create a dense pack. Consider vascular plug as an alternative — single device often sufficient for proximal occlusion. Gelatin sponge slurry can supplement coils for faster stasis.
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Complications
Expected effects, major and minor complications
Minor / Expected Complications
- Partial splenic infarction — expected with embolization, especially distal; usually asymptomatic or self-limited LUQ pain; more common with dSAE than pSAE
- Post-embolization syndrome — low-grade fever, LUQ pain, leukocytosis for 2–5 days; supportive management with antipyretics and analgesics
- Pleural effusion — left-sided; usually small and self-resolving; monitor clinically
- Coil/plug migration (minor) — if asymptomatic and does not cause ischemia; monitor
Major Complications
- Rebleeding requiring re-embolization or splenectomy — failure rate ~8% overall; higher for grade IV–V without SAE; repeat angiography + embolization vs surgical rescue
- Splenic abscess (~5%) — infected infarct; presents with fever, LUQ pain, leukocytosis; CT-guided drainage or splenectomy
- Pancreatitis — if coils migrate to or occlude pancreatic branches; monitor lipase
- Overwhelming post-splenectomy infection (OPSI) — if total splenic infarction results in functional asplenia; encapsulated organisms (Streptococcus pneumoniae, Neisseria meningitidis, H. influenzae); lifelong risk; requires vaccination
- Access-site complication — pseudoaneurysm, hematoma at CFA puncture site
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Pearls & Pitfalls
Clinical tips, vaccination protocol, splenic salvage outcomes
✦
Proximal embolization reduces perfusion pressure but preserves splenic function via short gastric, gastroepiploic, and dorsal pancreatic collateral pathways. Immunologic function is maintained after SAE, unlike splenectomy.
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Superselective (distal) embolization preferred when a focal injury is identified. Targets the specific bleeding vessel while preserving the remainder of splenic parenchymal perfusion. Higher minor complication rate (infarction) than proximal approach.
✦
Combined proximal + distal approach for AAST grade IV–V. Treat focal bleeds superselectively first, then deploy proximal coils/plug to reduce overall perfusion pressure. Note: combined approach has somewhat higher complication rates than either technique alone.
✦
Splenic salvage success rate >85% when SAE is used as adjunct to nonoperative management. SAE significantly reduces failure of nonoperative management, especially for grade IV–V injuries.
✦
Vaccination protocol if functional asplenia results: pneumococcal (PCV13 + PPSV23), meningococcal (MenACWY + MenB), and Haemophilus influenzae type B (Hib) vaccines. Administer 14 days post-procedure if possible, or at discharge. Coordinate with trauma and primary care teams.
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Do not delay splenectomy for uncontrolled hemorrhage. Nonoperative management with SAE is for hemodynamically stable or stabilizing patients. If the patient decompensates, communicate immediately with the surgical team.
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Up to 40% of major SAE complications occur in patients inappropriately triaged to nonoperative management. Multidisciplinary protocol adherence improves outcomes — ensure institutional protocols are followed for patient selection.
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Place proximal coils between the dorsal pancreatic and greater pancreatic artery origins. Coils placed too proximally risk occluding pancreatic branches (pancreatitis). Coils placed too distally fail to reduce perfusion pressure to the injury.
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References & Resources
Primary sources and key literature
Proximal vs Distal Approach Summary
- Proximal: shorter procedure time, lower minor complication rate, reduces perfusion pressure, preserves collateral flow; cannot easily re-embolize distally
- Distal: selective, treats focal injury, higher minor complication rate (infarction, abscess); can use coils, particles, Gelfoam, NBCA
- Both techniques show similar clinical efficacy for splenic salvage
Primary References
- Haan JM, Bochicchio GV, Kramer N, Scalea TM. Nonoperative management of blunt splenic injury: a 5-year experience. J Trauma. 2005;58(3):492–498.
- Bhullar IS, Frykberg ER, Siragusa D, et al. Selective angiographic embolization of blunt splenic traumatic injuries in adults decreases failure rate of nonoperative management. J Trauma Acute Care Surg. 2012;72(5):1127–1134.
- Habash M, Ceballos D, Gunn AJ. Splenic artery embolization for patients with high-grade splenic trauma: indications, techniques, and clinical outcomes. Semin Intervent Radiol. 2021;38(1):105–112.
- Banerjee A, Duane TM, Wilson SP, et al. Trauma center variation in splenic artery embolization and spleen salvage: a multicenter analysis. J Trauma Acute Care Surg. 2013;75(1):69–74.
- Schnuriger B, Inaba K, Konstantinidis A, et al. Outcomes of proximal versus distal splenic artery embolization after trauma: a systematic review and meta-analysis. J Trauma. 2011;70(1):252–260.
- Arvieux C, Frandon J, Tidadini F, et al. Splenic arterial embolization to avoid splenectomy (SPLASH) study group. JAMA Surg. 2020;155(12):1102–1111.