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

1. Asymptomatic carotid stenosis

Stenosis is classified as asymptomatic if there have been no stenosis-associated symptoms within the prior six months.

According to current guidelines, surgical desobliteration in asymptomatic carotid stenosis of least 60% may be recommended, provided that the perioperative risk of stroke is <3%. Moreover, patients should have a life expectancy of more than 5 years.

In asymptomatic carotid stenosis, patients with the following particular risk factors benefit from invasive treatment:

• Progressive stenosis under optimized medication including smoking cessation
• Occlusion of the contralateral internal carotid artery
• Contralateral symptomatic stenosis and ipsilateral high-grade asymptomatic stenosis
• Statin intolerance
• Adverse morphology of the carotid plaque, e.g., floating thrombi or ulcers
• Bleeding into plaque on MRI
• Microembolism in transcranial Doppler ultrasonography
• Silent infarction on CT or MR imaging
• Reduced cerebrovascular reserve

2.  Symptomatic carotid stenosis

Symptomatic carotid stenosis with luminal narrowing of 50% or more should undergo surgery, with a perioperative risk of stroke of <6%.

Timing

• In TIA or non-disabling stroke, if possible within the first 2 weeks (ruptured plaque with increased rate of re-embolization and increased risk of stroke)
• In crescendo TIA (recurrent carotid-associated TIAs in ever shorter intervals) as emergent surgery for secondary prevention
• In stable patients with regressive neurological symptoms of manifest stroke as early as possible; preoperative MRI detection of impaired intracranial barrier and progressive bleeding mandatory; interdisciplinary indication!

Carotid stenosis staging

• EEA is not suited for long stenosis of the internal carotid artery reaching far downstream; it is reserved for short stenosis close to the ICA origin
• Severe transmural calcification of the carotid bifurcation extending into the cranium
• History of neck dissection with radiotherapy
• Rarely morbid obesity with loss of neck contour
• Local florid infection, including ENT and dentistry
• Major cardiopulmonary comorbidity
• Severe neurological deficit requiring nursing care

Medical history

• Vascular risk factors Smoking, arterial hypertension, dyslipidemia, diabetes

Clinical neurological examination

• >90% of stenoses and occlusions of supraaortic vessels (ICA, vertebral artery, etc.) often remain clinically asymptomatic and are incidental findings during screening examinations or preoperative imaging studies
• Symptoms of a lesion in the vessels supplying the brain depend on the vessel involved, the course over time, and the prevailing collateral blood supply (e.g., via the cerebral arterial circle)
• Typical symptoms of impaired blood flow in the region supplied by the carotid artery (internal carotid artery) are:

         → Motor or sensory hemisyndrome (e.g. "hemiplegia")

         → Amaurosis fugax (transient unilateral blindness: opthalmic artery)

         → Cortical dysfunction (language, visuospatial perception)

         → Rather atypical: homonymous bilateral visual field impairment 

• Important: Carotid artery auscultation is inadequate for stenosis detection!

Cardiology examination

• 30% of patients present with CHD requiring treatment

Color flow Doppler imaging

Ultrasonography of the extracranial vessels supplying the brain should always study all vessels in both the transverse and axial plane:

• Common carotid artery from proximal to carotid bifurcation
• Carotid bifurcation with the posterolateral origin of the ICA
• External carotid artery
• Segments V1 to V3 of vertebral artery
• Subclavian artery and axillary artery

Search for hemodynamically relevant plaques and their morphological description ( B-mode):

• Hyperechoic versus hypoechoic
• Homogeneous versus inhomogeneous
• Smooth versus irregular contour

Plaque parameters with unfavorable prognosis:

• Hypoechoic internal plaque structure
• Extended plaque >1 cm
• Plaque diameter >4 mm
• Axial pulsation of the distal plaque

By international agreement, stenoses should be quantified according to the NASCET criteria.

Contrast-enhanced MR angiography or alternatively, CT angiography

• Validation of the findings or for treatment planning
• Assessment of intracranial vessels and possible parenchymal lesions (prior cerebral infarctions)

Digital subtraction angiography (DSA) of the arteries supplying the brain (rarely required)

• Only if the noninvasive procedures have proved inconclusive resulting in therapeutic consequences
• Example: stenotic kinking not evident on MRI or CT scan

CT or MRI of the brain

• In symptomatic patients, parenchymal imaging prior to elective revascularization
• In asymptomatic patients, such imaging can provide important additional insight, e.g., evidence of clinically silent cerebral infarction

Chest x-ray

Laboratory panels

• Blood count
• Electrolytes
• Coagulation
• Kidney function parameters
• Liver function parameters
• Blood lipids
• Blood group

In all patients with arteriosclerotic carotid stenosis, other sequelae of arteriosclerosis (coronary artery disease [CAD], peripheral arterial occlusive disease [PAOD]) should be assessed!

• Mark affected side
• Have patient fast 2–6 hours as per department protocol
• Continue platelet inhibitors; in combined anticoagulation, decide case-by-case based on cardiac risk profile

General surgical risks

• Major bleeding, blood transfusions, transmission of hepatitis/HIV through allogeneic blood transfusions
• Allergy/intolerance
• Wound infection
• Thrombosis/embolism
• Skin/vascular/nerve damage, e.g. due to patient positioning
• Keloid

Procedure-specific risks

• Cerebrovascular disorder/stroke
• Impaired blood supply to the eyes and even blindness
• Injury to cervical nerves: Hoarseness; loss of voice; dysphagia and dyspnea; angular palsy; shoulder elevation palsy
• Secondary bleeding, hematoma-induced tracheal compression, emergency surgical decompression
• Injury to carotid body (glomus caroticum): arrhythmia, blood pressure fluctuation
• Cardiopulmonary complications: myocardial infarction, pneumonia, pulmonary embolism
• Hyperperfusion syndrome:  seizures, neurological deficits, migraine-like headaches, cerebral edema/bleeding
• Suture aneurysm → re-operation
• Intraoperative angiography: contrast-induced renal failure

Risks specific to surgery with regional anesthesia (cervical plexus)

• Horner syndrome (drooping eyelid)
• Sensation of facial warmth, hoarseness, dyspnea
• Numbness of adjacent structures: brachial plexus, cervical spinal cord

• General anesthesia
• Regional anesthesia (cervical plexus) in cooperative patients; not in extremely high carotid lesions

Supine position with head moderately reclined (introduce a cushion under the shoulder blades) and rotated to the contralateral side. Both arms are adducted.

Pay special attention to patient positioning because older patients in particular present with varying degrees of cervical spine osteochondrosis, which may result in vertebral damage if positioning is unduly forced. If blood pressure is stable, the patient can be positioned in 10° anti-Trendelenburg position. This improves exposure of the carotid bifurcation, and helps to reduce venous pressure and venous bleeding somewhat.

The surgeon stands on the side to be operated on, with the assistant facing him/her and the scrub nurse next to the first assistant and toward the patient‘s feet. The second assistant stands beside the surgeon, toward the patient’s head. The upper wound angle can be exposed with a carotid retractor in lieu of the second assistant (Caution: pressure injury of facial nerve branches!).

In addition to the usual vascular instruments:

• Shunts of different diameters
• Retractors (e.g. Martin Retractor)
• Carotid retractor
• Special vascular clamps (e.g., Gregory-soft carotid clamps)
• Possibly equipment for intraoperative neuromonitoring  

Postoperative Analgesie

Folgen Sie hier dem Link zu PROSPECT (Procedures Specific Postoperative Pain Management) und zur aktuellen Leitlinie Behandlung akuter perioperativer und posttraumatischer Schmerzen.

Medizinische Nachbehandlung

• Überwachung auf Intermediare Care für 24 Stunden
• Kontrolle des OP-Situs: Halsumfang, Wundgebiet und Drainage
• Kreislaufüberwachung
• Laborkontrolle
• neurologische Kontrollen: am OP-Tag postop. sowie 2.-3. Tag postop.
• Entfernung Redondrainage am Folgetag sofern < 50 ml Sekret; Zug ohne Sog, um eine Läsion des N. vagus zu vermeiden
• Duplexkontrolle ab 3. Tag postop.
• ASS 100 1x1 , ggf. in Kombination mit Clopridogel
• Entlassung meist ab 5. Tag postop. möglich

Thromboseprophylaxe

•  i. Allg. niedermolekulares Heparin s.c. perioperativ alle 24 h    

Mobilisation

• normale Mobilisation ab dem 1. postop. Tag möglich

Krankengymnastik

•  in der Regel entbehrlich

Kostaufbau

• Trinken 6 Std. und kleine Mahlzeit  8 Std. postop.

Stuhlregulierung

•  in der Regel entbehrlich

Arbeitsunfähigkeit

• 2 – 4 Wochen

Follow up: Duplex-Sonografie nach 4-6 Wochen, nach ½ Jahr und dann jährlich. Risikofaktoren minimieren!