Complications - Left carotid bifurcation eversion endarterectomy (EEA) in symptomatic carotid bifurcation stenosis – Vascular Surgery

Perioperative stroke

The rate of perioperative stroke after carotid endarterectomy is 1-3%, in specialized centers <1%. 

1. CCA cross-clamping ischemia in the presence of inadequate intracranial collateral blood flow (circle of Willis)

• Awake patient (regional anesthesia): neurological symptoms such as unconsciousness, loss of speech, paralysis, restlessness
• Sleeping patient (general anesthesia):  e.g., non-pulsatile dark red back-bleeding; significant changes in EEG or SSEP (somatosensory evoked potentials) to below 50% of baseline despite adequate blood pressure; significant decrease in flow velocity in middle cerebral artery
• Recommendation: Before cross-clamping the CCA administer 3000-5000 IU of heparin i.v. (weight-adapted)
• → place a shunt with matching lumen from the common carotid artery into the internal carotid artery

2. Inadequate revascularization with turbulent flow

• Cause: residual plaque, elongation, stenotic kinking, endpoint edge/step-up in eversion TEA
• Effect: turbulent flow activating coagulation (platelet clotting)
• May result in perioperative stroke and early occlusion
• Prevention: technically correct repair, additional anticoagulation with 3000 -5000 IU heparin i.v. prevents thrombus formation
• Intraoperative angiography for quality assurance
• → operative revision/ mechanical recanalization
• → Immediate postoperative intraarterial lysis once cerebral hemorrhage has been reliably ruled out (imaging!); immediate postoperative systemic lysis is contraindicated in principle

3. Mobilization of plaque material during dissection and embolization

• Prevention: subtle dissection in no-touch technique
• → operative revision/ mechanical recanalization, possibly endovascular approach

4. Inadequate flushing of all run-in and run-off vessels to remove any clots from stasis

• → operative revision/ mechanical recanalization

5. Intimal cross-clamping injury in severe sclerosis of the common carotid artery run-in

• Local dissection remaining undetected
• May result in thromboembolism
• → operative revision/ mechanical recanalization

Hematoma/secondary bleeding

• According to the NASCET trial, 7.1% of all carotid endarterectomies, of which 3.9% were minor (no revision), 3% moderate (revision), and 0.3% major complications with permanent deficits or fatal outcome
• Episodes of hypertension during recovery and the early postoperative period increase the risk of secondary bleeding → intense monitoring for at least 8–12 hours
• Intubation made difficult or impossible due to airway obstruction, therefore rapid hematoma relief (if necessary at the bedside with provisional digital hemostasis, then intubation and surgical revision)
• Warning signs: inspiratory stridor, slurred or nasal speech, dysphagia

Wound infection

• Incidence about 1%
• Deep infections <0.5%
• Management of early and late superficial/deep infections of the soft tissues of the neck based on common standards
• Open and drain putrid infections early, AST-guided antibiotics
• Szilagyi grade III: synthetic material must be replaced by autologous material (autologous vein)

Szilagyi classifiction of extracavitary vascular graft infection

*Szilagyi DE, Smith RF, Elliott JP, Vrandecic MP. "Infection in arterial reconstruction with synthetic grafts." Ann Surg, 1972, 176 pp. 321-333.

Nerve injuries

1. Cutaneous nerves

• Depending on the literature reference, the injury rate for cutaneous nerves in the immediate postoperative period is as high as 69%, with a permanent injury rate of up to 26%.
• Sensory recovery is possible, but may take months
• Prognosis for recovery of protopathic sensitivity (pain and temperature sensation) more favorable, since the fibers terminate blindly in the subcutaneous tissue
• Persistent neuropathic pain after cutaneous nerve lesion is quite rare

2. Cranial nerves

• Incidence about 5–15%
• Mostly temporary and often reversible within one year
• Treatment: corticosteroids

Injury to neural structures in the surgical field of the carotid artery

Prevention of nerve injury

• Sound mastery of anatomy
• Careful dissection to identify and expose nervous structures in the surgical field
• Anticipate atypical anatomic variants and dissect them with special care
• Do not coagulate perineurial bleeders
• Avoid nerve compression by retractors

Hyperperfusion syndrome

• Rare neurological complication after TEA or stenting of ICA (incidence: 0.4–3%).
• Onset on postoperative day 5–7, with peak incidence on day 5
• Characteristic triad: severe headache, seizures, intracerebral hemorrhage
• Intracranial hemorrhage: 0.8–1.8%, mortality: 40–60% (!)
• Pathophysiology: Loss of intracerebral blood flow autoregulation
• Sequelae:
  • Stenosis-related primary hypoperfusion resulting in reactive maximum vasodilation of intracerebral vessels downstream
  • Following restoration of normal perfusion by TEA or stenting: edematous transmural transsudation owing to "capillary leaks" → cerebral edema, possibly also intracranial hemorrhage
• Risk factors: 
  • Marked postoperative hypertension
  • High-grade contralateral stenosis or occlusion of ICA
  • Status post ischemia and prior contralateral carotid TEA within the last 3 months
  • Also: significant correlation between clamping time and postoperative ipsilateral hyperperfusion
• Prevention:
  • Avoiding postoperative blood pressure spikes requires appropriate monitoring
• Management:
  • Forced reduction in blood pressure
  • Anticonvulsants
  • Anti edematous treatment of cerebral edema
  • Intubation/ventilation

Recurrent stenosis

• Incidence: around 1% per year
• Causes:
  • Progression of arteriosclerosis
  • Technical errors
  • Surgical technique  Eversion TEA, TEA + patch, stent PTA; patch type (vein, synthetic, homologous patch material)
• Treatment:
  • Indication: symptomatic or ICA stenosis >80%
  • Surgical; endovascular: stent PTA possible in recurrent stenosis following surgery

Pseudoaneurysm

• Rarely after TEA, usually years after use of synthetic materials
• Treatment: vein patch/graft