1.1.6 Treatment
1.1.6.1 Conservative treatment
Medical treatment is indicated in both internal carotid artery stenosis and vertebral artery stenosis, in order to limit atherosclerotic progression and reduce the risk of a neurological event. This treatment recommendation is independent of the decision on whether to offer interventional or surgical revascularization therapy. Treatments currently available include inhibition of platelets using acetylsalicylic acid (ASA), dipyridamole plus acetylsalicylic acid, or clopidogrel. In addition, treatment with statins is advised due to their anti-inflammatory and thus plaque-stabilizing effect in other vascular territories. Medical treatment alone is recommended in patients with stenosis of the internal carotid artery who either have a low risk of stroke (symptomatic stenoses < 50%, asymptomatic stenoses < 60%) or who are at high perioperative or peri-interventional risk due to comorbid conditions, or who have a limited life expectancy.
Drug treatment was the only form of therapy available for cerebral ischemia in the posterior flow region prior to the advent of endovascular approaches. Unfortunately, there is still a lack of data from randomized studies comparing drug treatment with surgical or interventional therapy for extracranial stenoses of the vertebral artery. The results of the Vertebral Artery Stenting Trial (VAST), which is currently still recruiting, will probably be able to provide important information. At present, 180 patients with symptomatic vertebral artery stenosis > 50% have been randomly assigned either to endovascular treatment (stent implantation) or to the conservatively treated group in the study.
1.1.6.2 Endovascular treatment
Patient preparation
Peri-interventional therapy
Technique of carotid artery stenting (CAS)
Access route
It is important to establish a safe vascular access route in order to minimize complications during carotid stent implantation, and access via the femoral artery is the approach most often employed. The common femoral artery is punctured using a Seldinger needle, and a 12-cm long 5–6F sheath is placed. This initial sheath is then exchanged during the procedure for a 90-cm long sheath (e.g., Cook Shuttle sheath.). If a guiding catheter is to be used, a 12-cm long 8–9F sheath is needed. In patients in whom the pelvic arteries are occluded or who have high-grade stenosis, or in situations in which the access route via the femoral artery is unavailable for other reasons, access via the brachial or radial artery is obtained (Fig. 1.1-11). The right brachial artery is preferable for interventions on both the right internal carotid artery and the left internal carotid artery. If neither access route is possible, direct cervical common carotid access (percutaneous or open surgical) can be considered.
Engaging the common carotid artery
Angiography of the aortic arch is generally performed prior to any selective carotid angiography in order to identify possible difficult anatomic conditions that might make it necessary to exchange the typically employed diagnostic catheters (e.g., Berenstein, Judkins Right, Head Hunter, IMA, JB-1) for an alternative one (e.g., Simmons or Vitek catheter) (Fig. 1.1-12). To engage the common carotid artery, the 5F diagnostic catheter (e.g., Berenstein, Right Judkins, Head Hunter, IMA) is positioned over a 0.035-inch hydrophilic guidewire in the ascending aorta with the catheter tip pointing downward. This technique reduces the likelihood of embolization from aortic plaque or traumatic injury to the intima of the aortic arch and prevents the catheter from becoming caught in a vascular ostium. As soon as the catheter reaches the ascending aorta, it is rotated 180°. This places the tip of the catheter in a vertical, upright position on fluoroscopy. The catheter is then carefully withdrawn until it slides into the brachiocephalic trunk, and the hydrophilic wire is then advanced into the right common carotid artery and the catheter is advanced over this wire into the common carotid artery. To intubate the left common carotid artery, the catheter is slowly withdrawn from the ostium of the brachiocephalic trunk. It should be rotated 20° counterclockwise, so that the catheter tip points slightly anteriorly. When the aortic arch becomes unwound with advancing age, the origin of the left common carotid artery is located slightly further posterior. In these cases, it may be necessary to rotate the catheter posteriorly instead.
Fig. 1.1–11a, b Access via the brachial artery.
Fig. 1.1–12a, b (a) Simple anatomic conditions. (b) More difficult anatomic conditions. The catheter is capable of prolapsing into the ascending aorta.
Once the left common carotid artery has been entered, the catheter should be rotated back 20° clockwise, so that the tip is once again pointing vertically or slightly posteriorly. The catheter position is checked by administering a small amount of contrast. This can exclude subintimal contrast flow or reduced blood flow. The hydrophilic wire is advanced to the distal common carotid artery, followed by the catheter.
Exploring the common carotid artery in difficult anatomy
If engagement of the common carotid artery is unsuccessful with the standard catheter, then a switch