9  Trauma - Endo

Authors: Kevin Kniery, Marlin “Wayne” Causey, Nakia Sarad, and Todd Rasmussen

These trauma episodes were developed in collaboration with Behind the Knife: The Premier Surgery Podcast. In addition, Dr. Causey is a co-host for WarDocs: Military Medicine Podcast.

Vascular trauma requires close collaboration between vascular surgeons and trauma surgeons. The decision of which specialty should manage which injuries vary across different centers. Through these trauma chapters we will discuss what management decisions the majority of vascular surgeons should be comfortable managing as a part of a multidisciplinary trauma team.

Take a Listen

Check our debate between leading trauma and vascular surgeons about how to best develop a collaborative team to manage vascular trauma.

For relevant images and a more in-depth discussion of this topic, please review Chapter 11: Resuscitative Endovascular Balloon Occlusion of the Aorta(Yi, Fox, and Moore 2022)and Chapter 17: Blunt Thoracic Aortic Injury(Demetriades, Talving, and Inaba 2022) in Dr. Rasmussen’s 4th Edition of Rich’s Vascular Trauma.

Although open surgical treatment is the mainstay of trauma management, there are some unique injuries where endovascular management has become the standard of care in centers with the resources and expertise to perform it.(Katsanos et al. 2009)

9.1 Blunt Thoracic Aortic Injury (BTAI)

9.1.1 Demographics

9.1.1.1 Guidelines

SVS Guidelines for Blunt Thoracic Aortic Injury(Lee et al. 2011)

9.1.1.2 Epidemiology

  • Rare, but lethal. Less than 1% of all blunt traumas but second leading cause of death in blunt trauma.

  • Due to high velocity mechanism of injury, usually are polytrauma patients with other severe injuries (i.e. intracranial injury)

  • Common mechanisms

    • High-speed motor vehicle collision

    • Motorcycle collisions

    • Pedestrian vs. motor vehicle

    • Falls from heights

  • Most patients have unsurvivable devastating injuries (75%) and pass prior to arrival to hospital for definitive care

  • Rates of paraplegia, rates of blood utilization, and mortality rates have decreased with prominence of endovascular repair of injuries

Further Reading

Seminal Papers in Blunt Thoracic Aortic Injury (BTAI) outlining the evolution of management from open to endovascular treatment.

  • Fabian et al. (1997). Prospective study of blunt aortic injury: Multicenter Trial of the American Association for the Surgery of Trauma. The Journal of Trauma, 42(3), 374–380(Fabian et al. 1997)

  • Demetriades et al. (2008). Diagnosis and treatment of blunt thoracic aortic injuries: Changing perspectives. The Journal of Trauma, 64(6), 1415–1418(Demetriades et al. 2008)

  • Alarhayem et al. (2021). Timing of repair of blunt thoracic aortic injuries in the thoracic endovascular aortic repair era. Journal of Vascular Surgery, 73(3), 896–902(Alarhayem et al. 2021)

9.1.1.3 Anatomy

  • Aortic arch >> relatively mobile

    • Not common location for blunt injury

  • Descending Thoracic aorta

    • Tethered

    • Junction just distal to left subclavian artery is where most injuries occur (within 0.5-2cm)

    • Tear injury due to deceleration

9.1.1.4 Grading Systems

SVS BTAI Grading System(Lee et al. 2011)

  • Grade I: Intimal Tear

  • Grade II: Intramural Hematoma

  • Grade III: Pseudoaneurysm

  • Grade IV: Rupture

Harborview Grading System(Heneghan et al. 2016; Starnes et al. 2012; Quiroga et al. 2019) - Classification scheme helps dictate which patients can be managed operatively vs. non-operatively

  • Minimal Injury

    • Absence of aortic external contour abnormality

    • Intimal tear and/or thrombus of <10mm in length or width

    • Treatment: No intervention and surveillance with follow-up imaging

      • Antiplatelet therapy

      • CTA at least within 30 days of injury, progression is rare (5-7%) and often identified early(Osgood et al. 2014)

  • Moderate Injury

    • External contour abnormality, includes pseudoaneurysms

    • Intimal tear >10mm in length or width

    • Treatment: Delayed repair, semi-elective

      • Stabilization of concomitant injuries(Azizzadeh et al. 2009)

      • Impulse control

        • Short-acting beta blocker (i.e. esmolol)

      • SBP < 120 (coordinate with neurosurgery for TBI patients)

      • Repair within 1 week (TEVAR)

        • For those patients with severe TBI who are unable to undergo anti-impulse therapy due to maintenance of cerebral perfusion pressure, will recommend repair sooner

    • Repeat CTA chest within 5-7 days for follow-up

  • Severe Injury

    • Active extravasation (free contrast extravasation or hemothorax at thoracotomy)

    • Hemodynamic instability

    • Left subclavian artery (LSA) hematoma > 15 mm

    • Treatment: Emergent repair

      • BTAI takes first priority
Take a Listen

Check the BTK episode with Dr. Benjamin Starnes discussing blunt thoracic aortic trauma and this classification scheme.

9.1.2 Evaluation

  • Be aware that patients likely have other injuries

  • Recommend CTA chest, abdomen, pelvis

  • Perform CTA follow-through to upper/lower extremities if those areas are of concern for injury

9.1.3 Management

Overview

  • Endovascular repair of BTAI has better outcomes than Open repair

  • Need to consider that most TEVAR devices are designed for aneurysmal disease

    • Generally require a larger diameter and their compliance is not ideal for these smaller/normal caliber aortic arch sizes

    • Average size of aorta proximal to injury site is 19mm (smallest devices are at 22mm)

    • Previously, iliac devices used to treat aortic injuries

  • There are new advanced TEVAR devices that are available for non-aneurysmal disease with normal caliber aortic sizes.

    • ex: GORE TAG Conformable Thoracic Stent Graft with ACTIVE CONTROL System

  • Recommend heparinization if not contraindicated

    • i.e. TBI, femoral shaft fracture with hematoma, solid organ injury, etc.

    • TEVAR can still be performed safely without heparin

    • Higher threshold for heparinization in COVID+ patients due to their hypercoagulable state

    • Goal Activated Clotting Time (ACT) > 250 - Ensure that ACT machine is available prior to start of case

Methods of Endograft Size Measurement

  • CTA imaging

    • Used to help measure aortic size

    • Need to consider that patient is usually hypovolemic, constricted, and young (so aorta more compliant/elastic) — true aortic size may be under-represented, 40% discrepancy between pre- and post-resuscitation, on imaging when choosing the appropriate device for repair

    • Recommend over-sizing stent graft by 20-25% from original measurement

  • Intravascular Ultrasound (IVUS)

Access

  • If iliac size is >7-8 mm, can use transfemoral access

  • Small iliacs (< 6mm) may need conduits

    • Recommend retroperitoneal approach for exposing common femoral and/or external iliac and using a Dacron conduit(Criado 2007)

  • If iliacs are diseased (i.e. calcium burden), use of conduits would be difficult

    • Can consider putting mineral oil over sheath to help pass and deliver the endograft

  • Femoral cutdowns considered to ensure safe delivery and removal of device

Positioning of Device

  • Most important aspect is to cover the proximal defect and seal the entry point

  • Average distance between the injury and the LSA is approximately 5.8mm (located at aortic isthmus)

  • Recommend 2cm coverage proximally of healthy vessel and 2cm coverage distally

    • With these recommendations, approximately 40% of TEVAR repairs cover the LSA

    • Preemptive revascularization of LSA is not necessarily required, most patients do fine without arm claudication

      • Complications to consider when covering LSA

        • Stroke

          • If there is concern for vertebral perfusion, LSA must be revascularized prior to covering

          • Left vertebral artery may be dominant or significant disease in right vertebral artery

        • Arm claudication and ischemia

        • Spinal cord ischemia

          • Rare

          • Collateral pathways between LSA and IMA (internal mammary artery) can be compromised

          • Spinal cord ischemia can present at end of case or delayed 24-72 hours post-operatively

          • Spinal cord drainage not routinely done to prevent paraplegia unless there is concern if abnormal neuro-exam.

            • If abnormal neuro exam at the end of the case, elevate blood pressure to improve perfusion and consider placing a drain at that time

            • There is high risk of placing and monitoring drains if not needed

      • Relative contraindications to covering LSA without revascularization

        • Dominant Left Vertebral Artery perfusion to brain

        • Right Vertebral Artery atherosclerotic disease

        • Hemodialysis access on ipsilateral arm

        • Prior CABG with LIMA (left internal mammary) to LAD (left anterior descending artery)

  • Some devices (i.e. GORE conformable as above) allow control of first stent ring to better conform/lay down the stent within the arch

Dealing with Malpositioned Devices

  • Can deploy too proximal or too distal

  • “Bird Beaking” - Where the lesser curve of the graft is not well approximated to the lesser curve of the aorta (i.e. the lifting of the inferior aspect of the most proximal endograft with the first covered stent ring now lifted off into the inner curve of the aortic arch)(Frohlich et al. 2020) This can cause endoleaks. Methods to avoid “bird beaking”

    • Use stiff wire to get into the aortic root (i.e. Amplatz or Lunderquist wires) with forward pressure to have a constant tension

    • Wire should be snug against the greater curvature of the aorta

    • Can consider taking the graft over the origin of the LSA

    • Allows more room in the flatter inner arch to lay the graft down

Timing of Repair

  • SVS Grade 3 or Harborview Classification of Moderate Injury

    • Delayed repair 24-48 hours after injury is acceptable and there is a survivable benefit(Alarhayem et al. 2021)

    • Some delays can be up to 5-7 days with medical management

    • Allows time for operative planning and optimization with anti-impulse therapy/resuscitation

    • Also enables evaluation of any underlying infectious process that may compromise and infect the endograft

  • SVS Grade 4 or Evolving SVS Grade 3/Harborview Moderate injuries

    • More urgent repair (within 24 hours)

9.2 Blunt Abdominal Aortic Injuries

9.2.1 Demographics

9.2.1.1 Epidemiology

  • Very Rare

  • Commonly associated with polytrauma patients, especially with concomitant blunt thoracic aortic injuries

  • Similar mechanisms of injury as BTAI

9.2.1.2 Anatomy

  • Zone 1: Diaphragm to SMA (superior mesenteric artery)

  • Zone 2: SMA to renal arteries

  • Zone 3: Inferior renal artery to aortic bifurcation

9.2.2 Evaluation

  • CTA

  • IVUS - Also used for operative planning and evaluating extent of defects into branches of the mesentery

9.2.3 Management

Overview

  • Zone 1 and 3 can be repaired endovascularly (above the SMA and below the renal arteries)

  • Can cover the celiac artery safely if there is no obvious compromise of the other mesenteric arteries (i.e. inferior mesenteric artery, internal iliac arteries, prior gastrectomy or other complex intra-abdominal operation)(Banno et al. 2020)

  • Zone 2 injuries typically repaired with open approach

  • Endovascular approach can minimize risk of contamination if there is bowel spillage etc.

  • Want to use minimum amount of endograft that will appropriately cover injury 2cm coverage proximally and 2 cm coverage distally

  • Injury can sometimes result in occlusion, which can also be treated endovascularly.

Types of Endografts Used - Can use combination of all grafts types to get the appropriate coverage

  • TEVARs

  • Covered stents

  • Aortic cuffs

9.3 Blunt Axillo-Subclavian Injuries

9.3.1 Demographics

Epidemiology

  • Very rare, 9% of all vascular trauma

  • Low incidence due to protection of vessels from surrounding bony structures and high degree of exsanguination with devastating injuries

  • Endovascular repair preferred due to location of these injuries and highly morbid open repair due to central hemorrhage and risk of brachial plexus injury.(Branco et al. 2016; DuBose et al. 2012)

  • Difficult to access via open methods with proximal/distal control due to protective anatomic nature of overlying skeleton

Anatomy

  • Thoracic Outlet

    • Axillo-subclavian vein located anterior to anterior scalene and runs between the first rib and clavicle through the subclavius muscle/tendon

    • Axillo-subclavian artery is located in the arterial triangle

      • More lateral than the axillo-subclavian vein

      • Courses posteriorly to anterior scalene

9.3.2 Management

Access

  • Transbrachial or transradial access preferred

  • Can combine transbrachial and transfemoral

    • Provides more options for delivering stent grafts with difficult aortic arches (anterograde and retrograde approach) via a through wire

  • With transbrachial access, brachial cutdown can be more reliable in trauma setting

  • Can also consider HYBRID approach

    • Gain proximal and distal control via through wires from transbrachial/transradial and then perform the open repair

    • Can perform coil embolization of subclavian arteries to gain control

      • Caution to vertebral perfusion

    • Stent graft to temporize injury and maintain in-line flow, then have interval axillary artery repair with a bypass (within a week to a month later)

Types of Endografts used

  • Self-expanding stents (i.e. Viabahn)

    • Traditional approach

    • May provide greater flexibility - important for mid-subclavian penetrating trauam due to mobility of this region. Stents in the axilla have particularly poor patency for this reason.(Chopra et al. 2016; Gray et al. 2017; Shalhub et al. 2011)

    • Helpful for more distal injuries

  • Balloon-expandable stents

    • Newer devices, also flexible

    • Has more precise landing (especially if injury is near branch points)