Arterial Injuries: Overview and Types

Arterial Injuries

• Definition: Sudden interruption of arterial supply to an organ or limb due to injury.

• Incidence: Common due to car accidents, war injuries, falls, or iatrogenic causes (like invasive procedures).

• Etiology:

• Open Injury: Stab wounds, gunshot wounds, or iatrogenic injuries.

• Closed Injury:

• Direct: Plaster or tourniquet compression, road traffic accidents.

• Indirect: Fractures or dislocations of bones (e.g., supracondylar humerus fracture causing brachial artery injury, supracondylar femur fracture causing popliteal artery injury).

• Types of Arterial Injury (Without Division):

• Arterial Spasm: Due to irritation near the artery (e.g., missile, cannulation). Often associated with intimal flap, thrombosis, or occlusion.

• Arterial Contusion: Outer arterial coat remains intact but can be associated with an intimal tear and superimposed thrombosis.

• Types of Arterial Injury (With Division):

• Complete Division: Both ends bleed profusely initially, but bleeding reduces due to intimal curls and media contraction. Divided stumps retract. Pulse is lost distally.

• Partial Division: Bleeding continues (pulsating hematoma). The pulse is weak distally.

• Mechanism of Injury: Trauma may cause spasm, intimal flap, subintimal hematoma, thrombosis/occlusion, hemorrhage, laceration, transection, or arteriovenous fistula.

• Clinical Picture: Includes history of trauma, general exam (vital signs to assess blood loss), and local exam (hard signs vs soft signs).

• Hard Signs: 6 Ps (pain, pulse, pallor, paresthesia, paralysis, poikilothermia), pulsatile hemorrhage, pulsatile hematoma, palpable thrill, bruit, and absent distal pulse. Urgent exploration without investigations needed.

• Soft Signs: Hematoma (non-pulsating, non-expanding), nerve injury, wound near major vessel, and delayed capillary refill time. Urgent investigations (angiography, Doppler, X-ray).

• Investigations: Blood tests (CBC, RBS, KFT, cross-matching), plain X-ray to detect foreign bodies (bullets) or fractures, Doppler and duplex scans to detect collaterals, and angiography (most accurate) to pinpoint the site of traumatic arteriovenous fistulas (AV fistula).

• Management:

• First Aid: Temporary control of bleeding (external compression, elevation, tourniquet). Anti-shock measures, antibiotics, and analgesics. Heparin injection. Fix associated fractures (stabilize repair.

• Definitive Treatment: Immediate exploration and fasciotomy (to prevent compartment syndrome), then treatment based on the type of arterial injury.

• No Division:

• Spasm: Intra-arterial papaverine injection or Fogarty balloon catheter dilatation. If unsuccessful, arteriotomy to identify intimal tear, excise spastic segment, and graft.

• Contusion: Excise the contused segment and graft.

• With Division:

• No gap: Direct end-to-end anastomosis.

• Gap: Small artery: natural graft (saphenous vein). Large artery: synthetic graft (Dacron or PTFE), or bypass.

• Partial Division:

• Longitudinal tear: Small artery: vein patch graft. Large artery: direct suture.

• Transverse tear: <1/2 circumference: direct anastomosis. > 1/2 circumference: turning the tear to complete before treatment.

• Intra-arterial Drug Injection: Drug addicts or anesthetists may inject into arteries instead of veins, leading to burning discomfort, coolness, cyanosis, and potential digital gangrene.

• Treatment: Heparin, dexamethasone, low molecular weight dextran, strong analgesics, and amputation for severe gangrene.

• Etiology: Drug addiction or during anesthesia induction.

Acute Compartment Syndrome

• Definition: Increased pressure within a closed compartment compromises blood circulation and tissue function.

• Limb Compartment Syndrome: Acutely raised pressure in the osseo-facial compartment of a limb, commonly in legs or forearms, but can occur in thighs, buttocks, feet or arms.

• Anatomy: Number of compartments in each limb are noted (e.g., Thigh: 3 compartments; Leg, Foot, Arm, Forearm, Hand = 4 each;).

• Common Causes: Ischemia and reperfusion injury, combined arterial and venous injuries, bone fractures, tight bandages (cast), and circumferential burns.

• Management: Remove constrictive bandages or casts, avoid elevating the affected limb, hydrate the patient with diuretics, and perform fasciotomy (surgical incision to relieve pressure).