Vascular Medicine. Thomas Zeller

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alt=""/> Obligatory shunt placement

      

Optional shunt placement after neuromonitoring

      The advantages of general shunt placement have been reported to include in particular the safe maintenance of perfusion to the internal carotid artery, enlargement of the artery by the shunt, and educational and training considerations. Arguments in favor of optional shunt placement, by contrast, include the relatively infrequent need for shunting, the greater effort involved, and the risk of injury to or dissection of the distal internal carotid artery. However, the results with the two procedures in relation to perioperative mortality and morbidity are probably similar (Girn et al. 2008; Woodworth et al. 2007).

      Methods of evaluating cerebral perfusion intraoperatively include measuring pressure in the stump of the internal carotid artery, assessment of somatosensory evoked potentials (SSEPs) or electroencephalography (EEG), and transcranial Doppler ultrasonography. However, there is controversy regarding the validity and practicality of these methods in the operating room. The use of such methods therefore depends on the preferences and experience of each surgical team.

      Intraoperative quality control

      Intraoperative quality control allows timely identification and correction of lesions capable of causing a cerebral insult. Such lesions include free-floating flaps > 2 mm and dissections with residual stenoses of more than 25%. Quality control can be carried out using the following methods:

      

Duplex ultrasonography

      

Continuous-wave (CW) Doppler

      

Angioscopy

      

Electromagnetic flowmetry

      

Angiography at two levels

      Postoperative follow-up

      

Frequent checking of blood pressure and heart rate is needed. Normotensive blood-pressure values should be achieved before the patient is discharged from the hospital.

      

Attention should be given to ipsilateral headaches/hyperperfusion (hemicephalalgia).

      

A neurological status check by personnel managing postoperative care should be carried out to survey for defects.

      

The patient should be allowed to drink clear fluids immediately. A normal diet can be resumed postoperatively after 6 h (or 3 h with regional anesthesia).

      

The patient should be mobilized after 6 h—e.g., sitting in a chair or walking in the corridor (if this is possible in view of prior neurological deficits).

      

A postoperative neurological examination should be carried out.

      

Long-term inhibition of platelet function should be managed with aspirin (100 mg/d), plus clopidogrel (75 mg/d) for a period of 6 weeks.

      

Plaque stabilization should be achieved with statins.

      

Risk factors should be checked (hypertension, diabetes, etc.).

      

For the period of the hospital stay, low-molecular-weight heparin should also be administered for prophylaxis against thrombosis (medium risk or higher due to other diseases).

      

Duplex ultrasonography check-up examinations of the carotid vessels are performed before discharge, after 4 weeks, after 6 months, and then annually.

      Clinical results

      High-grade hemodynamically relevant recurrent stenoses > 70% occur much less frequently in the carotid artery (2%) than in other arteries such as the superficial femoral artery (BQS-Bundesauswertung 2007). If they develop within 1 year, they are most often caused by intimal hyperplasia, while luminal strictures occurring later are usually due to progression of the atherosclerosis. Since recurrent stenoses and those secondary to radiation injury are rarely embolic, invasive therapy is only required if they have hemodynamic effects. However, surgical correction and prior cervical surgery are associated with a much higher risk of neural injury (5%) due to adhesions in the wound area (Mozes 2005). Paralysis of the contralateral vocal cord significantly increases the perioperative morbidity. Carotid artery stenting (CAS) therefore offers theoretical advantages given the lack of cranial nerve injury with the percutaneous procedure.

      False aneurysms are extremely rare surgical sequelae. They may be caused by incorrect surgical technique, such as an incorrect dissection level during endarterectomy, or by tearing or breakage of the patch suture. Very rarely, deep wound infection needs to be taken into consideration in aneurysms following alloplastic patch placement (with an incidence < 0.5%) (BQS-Bundesauswertung 2007). Treatment consists of complete removal of the patch and replacement with an autologous patch or bridging graft (from the great saphenous vein).

      General complications

      

Death (< 1%)

      

Cardiovascular complications (decompensated cardiac insufficiency, severe cardiac dysrhythmia, cardiac infarction) (1.9%)

      

Perioperative stroke (2.2%); 5–10% of cases are caused by intracerebral hemorrhage and the remainder are ischemic (BQS-Bundesauswertung 2007)

      Local complications

      

Postoperative hemorrhage requiring surgery (2.5%)

      

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