Treatment of Recurrent Stenosis After Previous Carotid Endarterectomy



Treatment of Recurrent Stenosis After Previous Carotid Endarterectomy



Boudewijn L. Reichmann, Gert Jan de Borst and Frans L. Moll


Carotid endarterectomy (CEA) is the gold standard in the treatment of carotid occlusive disease and prevention of stroke. However, the benefit of carotid revascularization is hampered by restenosis, which is associated with a modestly increased risk for stroke. Symptomatic recurrent stenosis has been reported to range between 0.6% and 3.6%, and asymptomatic restenosis, based on noninvasive studies, ranges from 8.8% to 19%. A systematic review in 1998 concluded that the risk of developing restenosis after CEA was 10% in the first year, 3% in the second year, and only 1% per year thereafter. The potential of a carotid restenosis to cause a stroke seems to be highly variable, but in general it is smaller than that of the primary lesion. The optimal treatment strategy for recurrent stenosis, especially when asymptomatic, remains a challenge.


Symptomatic patients with a recurrent stenosis greater than 70% or asymptomatic patients with a recurrent stenosis greater than 80% may be considered for reintervention. The site of recurrent stenosis is primarily situated at the ends of or within the confines of the original endarterectomy site and the suture lines. The recurrence lesion therefore is located in the internal carotid artery (ICA), the distal common carotid artery (CCA), or both. The majority (70%) of lesions are localized within the origin of the ICA. Some regions of the artery wall are exposed simultaneously to low wall shear stress and high mechanical stress, and these regions correspond to the areas where atherosclerotic lesions develop. It makes the carotid bulb a focus for disease because of its geometry coupled with pulsatile flow that produces low shear rates, which in turn promotes atherosclerosis.



Optimal Imaging for Assessment of Carotid Restenosis


In the distant past, conventional angiography was required to determine the degree of a carotid stenosis. However, an accurate alternative with no need to use intra arterial contrast agents was found in duplex ultrasonography. The severity of a stenosis has been defined using specific threshold velocities, including the peak systolic velocity (PSV), the end diastolic velocity (EDV), and/or the ICA/CCA PSV ratio. Most vascular laboratories use the (modified) Strandness criteria to grade restenosis after CEA. However, these criteria, established for evaluating primary carotid stenosis, might not be applicable in grading recurrent stenosis because of hemodynamic changes in the treated vessel.


Closing the arteriotomy with a patch widens the carotid diameter and decreases the stiffness of the arterial wall. This phenomenon is known as the dilatation or pantaloon effect following CEA. Hirschl and colleagues conducted a study to determine if patch angioplasty or direct closure of the ICA after CEA resulted in any hemodynamic or pathologic differences. Patients undergoing carotid patching with broadened bulb lumen exhibited statistically elevated turbulent flow disturbances with increased flow velocity in the ICA just distal to the patch. However, quantitative flow volume measurement did not reveal any differences between the two groups. Several papers have proposed new and revised ultrasound criteria, but there is still no consensus on the optimal criteria for grading recurrent carotid artery stenosis. It is therefore helpful to combine ultrasonography with an additional diagnostic modality, such as magnetic resonance imaging (MRI) or computed tomography (CT), to accurately evaluate the degree of stenosis.



Treatment Options for Recurrent Carotid Artery Stenosis


Whether recurrent carotid stenosis must be treated or not remains arbitrary. However, most authors agree that symptomatic restenoses warrant repeated intervention because of the risk of subsequent cerebrovascular events. Unfortunately, there are no reliable prognostic tests to differentiate between which highly stenotic lesions will cause a stroke and which will not. Most institutions therefore follow the consensus that reintervention should be considered in symptomatic patients with a recurrent stenosis of more than 70%, asymptomatic patients with a recurrent stenosis of more than 80%, patients with severe four-vessel disease, or patients with a contralateral occlusion. A second open procedure or endovascular intervention requires that the proposed treatment has a low periprocedural risk and provides long-term freedom from further cerebrovascular events.



Repeat CEA for Recurrent Carotid Stenosis


Repeat CEA for recurrent carotid stenosis in experienced hands can be performed with approximately the same complication rates as primary CEA. However, published complication rates for redo surgery vary. In guidelines by the American Heart Association, a stroke and death rate of less than 6% for symptomatic and less than 3% for asymptomatic patients have been considered acceptable for primary CEA versus a remarkable 10% threshold for repeat CEA. A major concern during redo surgery is the feared possibility of injuring adjacent structures such as cranial nerves and the internal jugular vein. The mandibular branch of the facial, vagus, glossopharyngeal, and hypoglossal nerves are all at risk. The structures tend to become adherent to the previous dissection plane and therefore can be harder to dissect during redo surgery. Reported rates of cranial nerve injury during repeat CEA are 0% to 7%; however, most of these injuries are transient. Such complications are within ranges suggested for primary carotid surgery.


If the site of the restenosis is predominantly situated in the distal part of the ICA, obtaining cephalad control may be very difficult. Mandibular subluxation or resection of the styloid process might be necessary in order to accurately place the clamp distal of the stenotic lesion. If the use of a Javid shunt is inevitable because of changes or asymmetry on cerebral monitoring, obtaining control of the distal ICA is of key importance. It is important to continue the dissection until 1 to 2 cm of uninvolved artery are circumferentially mobilized both proximally and distally.


In most cases, the restenotic plaque can be removed en toto through the cleavage plane that was used during primary surgery. The neointima and atherosclerotic plaque are usually not very adherent to the arterial wall. Most authors agree that the arteriotomy during redo surgery should not be closed primarily, but a patch closure should be performed.


De Borst and coworkers published a series of 73 consecutive procedures in 72 patients in which redo CEA was performed. The cumulative freedom from all stroke was 98% and from ipsilateral stroke 100% during a follow-up of 5 years. The cumulative freedom of re-restenosis (≥50%) was 85%, with five patients needing a tertiary carotid reconstruction. Other authors have also published large series (Table 1) with excellent long-term results (stroke-free survival 83%–100% and restenosis-free survival 84%–95% during long-term follow-up) and concluded that repeat CEA as a treatment for recurrent stenosis is a feasible, durable, and safe option.


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Aug 25, 2016 | Posted by in CARDIOLOGY | Comments Off on Treatment of Recurrent Stenosis After Previous Carotid Endarterectomy

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