26. Vascular trauma: complications; pseudoaneurysms

Vascular trauma: complications and pseudoaneurysms

Vascular trauma may be blunt, penetrating, iatrogenic or associated with fractures/dislocations. Injuries include laceration, transection, intimal flap, thrombosis, spasm, arteriovenous fistula and pseudoaneurysm.
Arterial injury threatens haemorrhage and distal ischaemia; venous injury causes haemorrhage, venous obstruction or embolic risk. The anatomical site and collateral circulation determine limb threat.

Hard signs of arterial injury include active/pulsatile bleeding, expanding haematoma, bruit/thrill, absent distal pulses with ischaemia and shock. These usually require immediate intervention.
Soft signs include history of bleeding, small stable haematoma, proximity to a major vessel, neurological deficit or diminished pulse. Compare bilateral pulses, capillary refill, temperature, motor and sensory function.
Document neurovascular status before and after reduction, splinting or intervention. Associated nerve, bone and compartment injuries are common.

An ankle-brachial or arterial pressure index may help screen stable extremity injuries; abnormal results require imaging or intervention.
Duplex ultrasound assesses flow, pseudoaneurysm and arteriovenous fistula. CT angiography is commonly used in stable patients to map injury and plan repair.
Catheter angiography may be diagnostic and therapeutic. Do not delay haemorrhage control in unstable patients with hard signs.

A pseudoaneurysm is a contained arterial wall disruption in which blood escapes through the wall but is confined by surrounding tissue, forming a communicating sac.
Causes include penetrating/blunt trauma, arterial puncture, catheterisation, surgery and infection. Common sites include femoral, radial and traumatic peripheral arteries.
Features include a pulsatile mass, bruit, pain, swelling, distal embolisation, nerve compression or skin compromise. A pseudoaneurysm may thrombose or rupture.
Duplex ultrasound demonstrates a sac communicating with an artery and a characteristic 'to-and-fro' waveform at the neck. CT angiography is useful for deep or complex lesions.

Control haemorrhage with direct pressure, tourniquet when indicated, resuscitation and urgent vascular consultation. Repair options include primary repair, patch angioplasty, interposition graft, bypass or endovascular stent/embolisation.
Pseudoaneurysm treatment depends on size, site, symptoms, neck anatomy, infection and distal perfusion. Options include observation for selected small stable lesions, ultrasound-guided compression, thrombin injection, covered stent or open repair.
Infected pseudoaneurysms generally require surgical source control and antimicrobial therapy; thrombin injection is inappropriate in infection.
Complications include exsanguination, thrombosis, distal emboli, compartment syndrome, nerve injury, infection, limb loss and recurrent pseudoaneurysm.