Residency · Residency · Vascular Surgery

Endovascular Approaches to Vascular Trauma

Overview

Endovascular techniques have become increasingly prominent as either first-line or adjunctive treatments for vascular trauma. These approaches offer several advantages, including reduced operative time, decreased blood loss, avoidance of hostile surgical fields, and rapid hemorrhage control. The key modalities employed in this context include Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA), covered stent grafts, coil or plug embolization, and Thoracic Endovascular Aortic Repair (TEVAR) specifically for blunt thoracic aortic injury. For complex injuries, hybrid approaches that combine open surgical and endovascular techniques often provide the optimal management strategy.

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA)

Concept

REBOA involves the temporary occlusion of the aorta using an endovascular balloon to control hemorrhage and augment proximal blood pressure. It serves as the endovascular equivalent of a resuscitative thoracotomy with aortic cross-clamping but is less invasive. This procedure can be performed rapidly in the emergency department or trauma bay, providing a critical bridge to definitive hemorrhage control.

Aortic Zones for REBOA

The aorta is divided into three zones for REBOA placement. Zone I extends from the left subclavian artery to the celiac trunk and is targeted for abdominal hemorrhage involving organs such as the liver, spleen, mesentery, aorta, or pelvis. Zone II, spanning the paravisceral aorta between the celiac artery and the lowest renal artery, is avoided because balloon inflation here risks ischemia to vital visceral and renal arteries. Zone III covers the infrarenal aorta, from below the renal arteries to the aortic bifurcation, and is used for pelvic or junctional hemorrhage, such as from pelvic fractures or iliac artery injuries.

Technique

Access is typically obtained via the common femoral artery, either by surgical cutdown or percutaneous ultrasound-guided puncture. A sheath ranging from 7 to 12 French is inserted depending on the device used. The ER-REBOA catheter (Prytime Medical) is commonly employed and allows for partial occlusion. The catheter is advanced to the target zone under fluoroscopic guidance, or by external landmarks if fluoroscopy is unavailable. For Zone I, the catheter tip is positioned approximately 45 cm from the femoral access site, while for Zone III, it is about 25 cm. The balloon is then inflated to achieve proximal hemodynamic support, after which the patient is transitioned to definitive hemorrhage control in the operating room or angiography suite.

Partial REBOA (pREBOA)

Partial REBOA involves controlled partial inflation of the balloon to allow some distal blood flow, thereby reducing ischemia-reperfusion injury compared to complete occlusion. The ER-REBOA catheter is specifically designed for titrated occlusion, which extends the safe duration of balloon inflation.

Limitations and Complications

The maximum safe occlusion time is approximately 60 to 90 minutes for Zone I, with somewhat longer tolerances for Zone III. Ischemia-reperfusion injury remains a significant concern, manifesting as distal ischemia affecting the kidneys, gut, and lower extremities, along with metabolic acidosis and hyperkalemia upon balloon deflation. Access-related complications include iliac artery injury and dissection, particularly in patients with small or atherosclerotic vessels. Importantly, REBOA does not treat the source of hemorrhage but only temporizes bleeding to allow time for definitive repair. It is not indicated for thoracic hemorrhage because the bleeding is proximal to the balloon placement.

<image>Anatomical diagram showing REBOA balloon catheter placement in Zones I and III of the aorta, with labeled aortic zones, and the femoral artery access site with deployment of the occlusion balloon</image>

Covered Stent Grafts for Traumatic Arterial Injuries

Indications

Covered stent grafts are indicated for arterial injuries located in anatomically challenging sites such as the subclavian, axillary, and iliac arteries. They are also used to treat traumatic pseudoaneurysms, arteriovenous fistulae, and active hemorrhage that is amenable to endovascular exclusion. These devices are particularly valuable in patients who are too unstable to tolerate prolonged open surgical repair.

Subclavian and Axillary Artery Injuries

Proximal subclavian artery injuries are notoriously difficult to access surgically, often requiring sternotomy or thoracotomy. Covered stent grafts such as Viabahn or iCAST/Atrium can be deployed percutaneously or via surgical cutdown, offering excellent results with reduced morbidity compared to open approaches. When deploying stents in this region, coverage of the vertebral artery must be considered; fortunately, this is usually well tolerated if the contralateral vertebral artery is patent. However, long-term patency data for these devices in young trauma patients remain limited.

Iliac Artery Injuries

Iliac artery injuries often occur in association with pelvic fractures and are frequently seen in hemodynamically unstable patients. Covered stent grafts provide rapid hemorrhage control and can serve either as a bridge to definitive repair or as definitive treatment themselves. For internal iliac artery injuries, coil embolization is generally preferred over stent graft placement.

Peripheral Artery Injuries

Covered stent grafts are also used for femoral and popliteal artery pseudoaneurysms and arteriovenous fistulae. Caution is warranted in the popliteal region due to the risk of stent fracture from knee flexion. In young patients, the long-term implications of stent durability and the need for surveillance should be carefully considered.

Embolization for Branch Vessel Hemorrhage

Techniques

Several embolization techniques are employed to control hemorrhage from branch vessels. Coil embolization involves deploying metallic coils, either detachable or pushable, to occlude bleeding vessels. Gelfoam embolization uses a temporary agent that allows vessel recanalization within two to four weeks. Vascular plugs, such as the Amplatzer device, are used for occluding larger vessels. Liquid embolics like n-butyl cyanoacrylate (glue) are effective for small vessels and arteriovenous fistulae.

Common Applications

Pelvic fracture hemorrhage is the most common indication for traumatic embolization, typically involving branches of the internal iliac artery. Bilateral internal iliac embolization may be necessary, with Gelfoam preferred to preserve collateral flow. Embolization is also used for solid organ injuries, targeting the splenic artery (where proximal embolization helps preserve splenic function), hepatic artery branches, and renal artery branches. Intercostal and lumbar artery hemorrhage following thoracolumbar trauma, as well as facial and neck hemorrhage involving branches of the external carotid artery (such as the internal maxillary and facial arteries), are other common indications.

Pelvic Fracture Hemorrhage Algorithm

In patients who are hemodynamically unstable with pelvic fractures, initial management includes application of a pelvic binder to reduce pelvic volume and provide tamponade, along with activation of a massive transfusion protocol. If arterial bleeding is suspected, angiography with embolization is performed. When venous or bony bleeding predominates, preperitoneal packing serves as damage control. REBOA placed in Zone III can be used as an adjunct or bridge to definitive control. Hybrid approaches combining preperitoneal packing and selective embolization in a hybrid operating room are increasingly utilized.

<image>Angiographic images showing active hemorrhage from an internal iliac artery branch following pelvic fracture, with successful coil embolization achieving hemostasis on completion angiography</image>

Blunt Thoracic Aortic Injury (BTAI)

Mechanism

Blunt thoracic aortic injury typically results from rapid deceleration mechanisms such as high-speed motor vehicle collisions or falls from height. The aortic isthmus, located just distal to the left subclavian artery, is the most common site of injury, accounting for over 90% of cases. This region is a fixed point due to the ligamentum arteriosum, which creates differential shear stress during sudden deceleration. Mortality is high, with 80 to 90% of patients dying at the scene; those who reach the hospital usually have contained injuries.

Classification (Azizzadeh/SVS)

The injury is classified into four grades. Grade I represents an intimal tear without external contour abnormality. Grade II involves an intramural hematoma characterized by an intimal flap or a small pseudoaneurysm involving less than 50% of the aortic circumference. Grade III is a pseudoaneurysm involving more than 50% of the circumference. Grade IV denotes free rupture, which leads to hemodynamic collapse.

Diagnosis

CT angiography with intravenous contrast is the gold standard for diagnosis, offering greater than 98% sensitivity and specificity. Imaging findings include pseudoaneurysm formation, intimal flaps, periaortic hematoma, and mediastinal hematoma. Chest X-ray may show signs such as a widened mediastinum, abnormal aortic contour, a left apical cap, or depression of the left mainstem bronchus, but these findings have low sensitivity and CTA is required for definitive evaluation.

Management

For Grade I intimal tears, non-operative management with serial imaging (CTA at 1, 3, and 6 months) is appropriate, as most lesions resolve or remain stable. Anticoagulation is not indicated in the trauma setting. Grades II and III, involving intramural hematoma or pseudoaneurysm, are primarily managed with TEVAR, which now treats over 90% of such injuries. Delayed repair, typically 24 to 72 hours after injury, is preferred when possible to allow stabilization of associated injuries. During observation, medical management focuses on heart rate control (less than 100 beats per minute) and blood pressure control (systolic blood pressure below 120 mmHg) using agents such as esmolol and nicardipine. Early repair is indicated for hemodynamic instability, expanding pseudoaneurysm, or uncontrolled hemorrhage. Grade IV injuries with free rupture require emergent intervention, either open repair or TEVAR, depending on institutional resources, but mortality remains high regardless of approach.

TEVAR for Blunt Thoracic Aortic Injury

Technical considerations for TEVAR include the landing zone, which often necessitates coverage of the left subclavian artery origin due to the proximity of the injury. Coverage of the left subclavian artery is generally well tolerated if the left vertebral artery and the circle of Willis are intact. Revascularization with carotid-subclavian bypass is considered if the left vertebral artery is dominant, if the patient has had prior coronary artery bypass grafting using the left internal mammary artery, or if there is an arteriovenous fistula in the left arm. Device selection typically involves thoracic stent grafts such as Gore TAG, Medtronic Valiant or Captivia, and Cook Zenith TX2. These devices are often oversized relative to the aortic diameter in young patients, which is a significant concern, although some devices have conformable designs suitable for smaller aortas. Access is usually via the femoral or iliac arteries, with iliac conduits sometimes required in young patients with small vessels. The risk of spinal cord ischemia is very low for isolated descending TEVAR covering less than 20 cm of the aorta.

There is controversy regarding TEVAR in young patients because the long-term durability of these devices is unknown; they were originally designed for elderly patients with aneurysmal disease. The young aorta continues to grow, raising concerns about graft migration, endoleak, and the need for reintervention. Material fatigue and stent fracture over decades are also potential issues. Despite these concerns, TEVAR has become the standard of care due to dramatically lower perioperative mortality rates (7-8%) compared to open repair (15-20%). Lifelong surveillance is required, and future reinterventions may be necessary.

Open Repair (Historical Standard)

Open repair involves a left posterolateral thoracotomy with aortic cross-clamping or left heart bypass/cardiopulmonary bypass, followed by interposition grafting with Dacron. This approach carries higher perioperative mortality (15-20%), a risk of paraplegia (5-15%), and increased morbidity. Open repair remains indicated when TEVAR is not feasible due to anatomical or access issues, when concomitant thoracic injuries require thoracotomy, or in very young patients such as neonates and children.

<image>CT angiography showing a Grade III blunt thoracic aortic injury with contained pseudoaneurysm at the aortic isthmus, and post-TEVAR image demonstrating stent graft exclusion of the pseudoaneurysm with preserved aortic flow</image>

Hybrid Approaches

Hybrid Operating Room

Hybrid operating rooms combine open surgical and endovascular capabilities within a single suite. They feature fixed fluoroscopy systems, either ceiling or floor-mounted C-arms, and angiographic tables. This setup allows for damage control laparotomy alongside simultaneous angiographic evaluation and intervention, and is becoming standard in major trauma centers.

Combined Techniques

Hybrid approaches may involve open surgical control combined with endovascular repair, such as femoral artery exposure for sheath placement followed by stent graft deployment for iliac or aortic injuries. Other combinations include open thrombectomy with completion endovascular stenting for residual injury, surgical bypass coupled with endovascular embolization of excluded segments, or open vascular repair alongside endovascular treatment of associated injuries at different sites.

Clinical Pearls

REBOA should be viewed as a temporizing measure rather than a definitive treatment; occlusion time must be minimized, and definitive hemorrhage control should be achieved as soon as possible. In blunt thoracic aortic injury, anti-impulse therapy aimed at maintaining a heart rate below 100 beats per minute and systolic blood pressure under 120 mmHg is the initial treatment regardless of the timing of repair and should be initiated promptly in the emergency department. TEVAR has largely supplanted open repair for blunt thoracic aortic injury due to its dramatically lower mortality, but young patients require lifelong surveillance for device-related complications. Coverage of the left subclavian artery during TEVAR is frequently necessary and generally well tolerated; however, assessment of the posterior circulation is essential before coverage. In pelvic fracture hemorrhage, the bleeding source is most often venous or bony; angiographic embolization targets arterial bleeding, while preperitoneal packing addresses the larger venous component. Covered stent grafts for subclavian artery injuries avoid the morbidity associated with sternotomy or thoracotomy and yield excellent short-term outcomes. In young trauma patients, the benefits of endovascular repair must be weighed against the unknown long-term durability of devices, but in the acute setting, survival takes precedence over theoretical long-term concerns.

References

• Starnes BW, et al. Management of blunt aortic injury: AAST/WTA practice management guideline. J Trauma Acute Care Surg. 2020;89(6):1150-1161.
• DuBose JJ, et al. AORTA registry: multicenter analysis of TEVAR for traumatic aortic injury. J Trauma Acute Care Surg. 2015;78(4):721-727.
• Brenner ML, et al. Use of REBOA for hemorrhage control. J Trauma Acute Care Surg. 2014;77(6):921-925.
• Fox CJ, et al. The role of endovascular approach in vascular trauma. Perspect Vasc Surg Endovasc Ther. 2011;23(3):165-170.
• Azizzadeh A, et al. An outcome analysis of endovascular versus open repair of blunt traumatic aortic injuries. J Vasc Surg. 2013;57(1):108-115.

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