Angioplasty and Stenting
♦ Preoperative
Operative Planning
- Routine preoperative evaluation similar to that for CEA
- Imaging studies: magnetic resonance angiography, computed tomography angiography, Doppler
- Premedication with antiplatelet medications
- Aspirin 325 mg daily beginning 3 days prior and continuing indefinitely
- Clopidogrel 300 mg load (75 mg for 4 days prior to surgery preferred; single 300 mg dose before procedure acceptable) then 75 mg daily for 4 to 6 weeks postprocedure
- Aspirin 325 mg daily beginning 3 days prior and continuing indefinitely
- Special equipment
- As for retrograde percutaneous femoral artery puncture
- One 5 French (F) catheter (for diagnostic angiogram)
- One 6F guiding sheath or 7F guiding catheter
- Filtration protection device on 0.014 nitinol wire, self expanding stent—choose to assure compatibility with artery size (exact device varies with vendor)
- 0.035-inch guide wire and micro–guide wires
- As for retrograde percutaneous femoral artery puncture
Anesthetic Issues
- Administer minimal intravenous sedation and perform under local anesthesia at puncture site as much as possible.
- General anesthesia is rarely given and is generally discouraged.
- Intravenous anticholinergic agent such as atropine or glycopyrronium bromide may be given immediately before carotid sinus manipulation.
- Protamine should be readily available in the unlikely event that intraoperative rupture occurs.
- Electrocardiogram and invasive blood pressure monitoring
- Electroencephalogram monitoring or transcranial Doppler monitoring are optional.
♦ Intraoperative
- Positioning
- The patient is placed in the supine position.
- Intravenous antibiotics, if needed, are given.
- A Foley catheter is placed.
- The proper radiation shielding is placed on the patient.
- Both inguinal areas are shaved and prepped with iodine solution.
- A sterile drape is placed over the prepped areas.
- The head is positioned in neutral position and gently taped in place.
- The patient is placed in the supine position.
- Technique
- Femoral artery puncture is performed, and a 5F sheath for diagnostic angiography and 6F sheath for stent deployment are inserted.
- Femoral sheath is sutured in place.
- Introducing catheter is advanced in retrograde fashion up to the aortic arch.
- A complete diagnostic four-vessel angiogram is useful to assess collaterals.
- Intravenous heparin up to 70 U/kg initially, and then an hourly dose of 35 U/kg is administered to maintain activated clotting time 2 to 2.5 × baseline (usually 250 to 300 second)
- A 6F guiding sheath is placed in the cervical carotid; caution must be taken to maintain flow and prevent iatrogenic vasospasm.
- Several characteristics of the lesion must be measured: length, tapering segments, diameter of the artery proximal and distal to the lesion
- Most commonly, if the stenosis is not severe, a filtration protection device can be placed primarily across the stenosis and deployed in a relatively normal segment of the internal carotid artery beyond the stenosis.
- Occasionally, predilatation with a small caliber angioplasty balloon (1.5 to 3 mm) is necessary over a micro–guide wire before placement of the filtration device, although this is discouraged.
- Angiogram is performed to ensure appropriate placement of the filtration device and adequacy of blood flow in the carotid artery.
- After crossing the stenosis, the tip of the exchange wire is maintained in a stable, distal location during tracking of the stent and balloon delivery to prevent damage to the carotid artery or generation of cerebral emboli.
- If the microcatheter is necessary, exchange for the stent microcatheter (primary stent angioplasty) or balloon microcatheter (secondary sent angioplasty).
- Exchange wire removed only after lesion is visualized with high-resolution control angiography
- Blood flow is evaluated throughout to detect signs of proximal vasospasm or dissection.
- Primary angioplasty is used if balloon-mounted stent catheter is too cumbersome to pass lesion.
- Balloon angioplasty and stent placement should cover area of lesion; extension of the stent into the common carotid artery is often performed to ensure coverage of the entire plaque.
- If a stent cannot be accepted primarily, an undersized balloon is inflated to create necessary caliber.
- Balloon is passed over guide wire and inflated to appropriate pressure (12 to 21 atm) depending upon the type of balloon used and the appropriate diameter required to treat the stenosis; complete luminal restoration is not required.
- Careful monitoring of vital signs during balloon expansion is mandatory as severe hypotension and asystole are potential complications.
- Femoral sheath is usually removed immediately following the procedure using one of several available arteriotomy closure devices; anticoagulation should not be reversed to facilitate sheath removal.
- An arterial access catheter may be maintained in position and removed once activated clotting time has normalized although there may be a small risk of resultant bacteremia.
- Patient is usually hospitalized for a minimum of 24 hours.
- After crossing the stenosis, the tip of the exchange wire is maintained in a stable, distal location during tracking of the stent and balloon delivery to prevent damage to the carotid artery or generation of cerebral emboli.
- Femoral artery puncture is performed, and a 5F sheath for diagnostic angiography and 6F sheath for stent deployment are inserted.
♦ Postoperative
- Postoperative check includes inspection of femoral artery site for hematoma and distal leg for ischemia secondary to thrombosis.
- Intensive care monitoring of vital signs and neurologic status
- Hemodynamic support to maintain systolic blood pressure 100 to 140, adjusting as needed based on comorbidities
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