Residency · Residency · Interventional Radiology
Hepatic and Renal Trauma Embolization
Introduction
The liver and kidneys are among the most commonly injured solid organs in abdominal trauma. Non-operative management (NOM) is the standard for hemodynamically stable patients, with transcatheter arterial embolization (TAE) serving as a critical adjunct to improve NOM success rates. Understanding the vascular anatomy, injury patterns, and embolization techniques specific to each organ is essential for the interventional radiologist.
Hepatic Trauma
Anatomy
Dual blood supply: hepatic artery (25-30% of blood flow) and portal vein (70-75%). The common hepatic artery arises from the celiac trunk and gives rise to the proper hepatic artery, which bifurcates into right and left hepatic arteries. Variant anatomy is common: replaced or accessory right hepatic artery from SMA (15-20%), replaced left hepatic artery from left gastric artery (10-15%). Understanding variant anatomy is critical for complete angiographic evaluation.
AAST Liver Injury Scale
| Grade | Description | Management |
|---|---|---|
| I | Subcapsular hematoma <10% surface; laceration <1 cm depth | Conservative |
| II | Subcapsular hematoma 10-50%; laceration 1-3 cm depth | Conservative |
| III | Laceration >3 cm depth; subcapsular hematoma >50% | NOM +/- embolization |
| IV | Parenchymal disruption 25-75% of lobe; active hemorrhage | Embolization or surgery |
| V | Parenchymal disruption >75% of lobe; juxtahepatic venous injury | Surgery or embolization |
Grades III-V with CTA extravasation or pseudoaneurysm are candidates for embolization.
Embolization Technique
Celiac arteriography followed by selective hepatic arteriography. Identify bleeding branch and advance microcatheter to the bleeding site. Superselective embolization is preferred to preserve hepatic parenchyma. Embolic agents: microcoils for named branches; Gelfoam for diffuse hemorrhage. The dual blood supply of the liver provides a safety margin; hepatic artery embolization is generally well tolerated. Completion angiography must include evaluation for variant anatomy sources of hepatic blood supply.
Complications of Hepatic Embolization
Hepatic infarction: usually well tolerated due to portal venous supply; may cause transient LFT elevation. Liver abscess: 1-3%; risk increases with large areas of devitalized tissue; managed with percutaneous drainage. Biloma: bile collection from ductal injury; managed with percutaneous drainage and possible ERCP. Gallbladder ischemia: if the cystic artery is inadvertently embolized. Re-bleeding: 5-10%; may require repeat embolization or surgery.
Special Hepatic Considerations
Hepatic pseudoaneurysm: may present with delayed hemorrhage (days to weeks); requires embolization even if asymptomatic. Hemobilia: GI bleeding from communication between hepatic artery and biliary tree; classic triad of RUQ pain, jaundice, and GI bleeding. Arterioportal fistula: abnormal communication between hepatic artery and portal vein; may cause portal hypertension.
Renal Trauma
Anatomy
Renal arteries arise from the aorta at L1-L2; typically single but accessory arteries present in 25-30%. Segmental arteries are end arteries with no significant collateral supply. The kidney is less tolerant of embolization than the liver; superselective technique is critical.
AAST Kidney Injury Scale
Grade I: contusion or non-expanding subcapsular hematoma. Grade II: non-expanding perinephric hematoma; laceration < 1 cm depth without collecting system injury. Grade III: laceration > 1 cm without collecting system injury. Grade IV: laceration into collecting system; segmental renal artery or vein injury with hemorrhage; segmental infarction. Grade V: shattered kidney; main renal artery or vein avulsion/thrombosis.
Indications for Renal Embolization
Active extravasation on CTA in a hemodynamically stable patient. Pseudoaneurysm or arteriovenous fistula identified on CTA. Persistent or delayed hematuria with identifiable vascular injury. Grade IV-V injuries with arterial hemorrhage in patients being managed non-operatively. Hemodynamic instability with renal source refractory to resuscitation may require nephrectomy.
Embolization Technique
Aortography to assess bilateral renal arteries and identify accessory vessels. Selective renal arteriography followed by superselective microcatheter advancement. Microcoil embolization of the specific bleeding segmental or subsegmental artery. Minimize the volume of infarcted parenchyma; every nephron counts. Gelfoam may be used as an adjunct for diffuse hemorrhage within a segment. Avoid proximal main renal artery embolization unless the kidney is unsalvageable.
Complications of Renal Embolization
Renal infarction: expected consequence of segmental embolization; minimize volume. Loss of renal function: risk is proportional to the volume of embolized parenchyma. Post-embolization syndrome: flank pain, fever; managed supportively. Renal abscess: rare; managed with percutaneous drainage. Hypertension: Page kidney (compression of renal parenchyma by hematoma) or renal artery stenosis from injury.
Post-Procedure Management for Both Organs
ICU monitoring: serial hemoglobin, vitals, urine output. Repeat CTA at 48-72 hours for high-grade injuries. Monitor for delayed pseudoaneurysm formation (weeks after injury). Hepatic injuries: follow LFTs, monitor for biloma and abscess. Renal injuries: follow creatinine, monitor for hypertension and delayed urinoma.
Key Clinical Pearls
Superselective embolization is the goal for both hepatic and renal trauma to preserve maximum parenchyma. The liver tolerates embolization well due to dual blood supply; the kidney is less forgiving as segmental arteries are end arteries. Variant hepatic arterial anatomy must be identified to avoid missing a bleeding source. Delayed pseudoaneurysm is a recognized complication of both hepatic and renal injuries; follow-up imaging is essential. Non-operative management with adjunctive embolization is the standard for hemodynamically stable solid organ injuries.
References
- Defined the Core Practice Guidelines. AAST Organ Injury Scaling 2018 Update. Journal of Trauma and Acute Care Surgery. 2018;85(6):1119-1122.
- Defined the Core Practice Guidelines. Defined the Clinical Standards. EAST Practice Management Guidelines: Non-operative Management of Blunt Hepatic Injury. 2012.
- Defined the Core Clinical Practice. Defined the Practice Standards. Morey AF et al. AUA Uropelvic Guidelines for Renal Trauma. Journal of Urology. 2014;192(2):316-324.
- Defined the Core Competencies. Defined the Practice Standards. SIR Guidelines for Trauma Embolization. 2020.