Carotid Endarterectomy

Carotid endarterectomy (CEA) is used to treat symptomatic extracranial internal carotid artery stenosis. The occult stroke of CEA patients evaluated by magnetic resonance imaging 3 days after operation was as high as 17%. Cerebral blood flow autoregulation (CA) is the ability of the brain to maintain the relative stability of cerebral blood flow, and cerebral oxygen index (COx) can be used to reflect CA. A negative value of cerebral oxygen index or a value near zero indicates that CA is complete, and cerebral oxygen index close to 1 indicates that CA has lost its ability. In theory, real-time monitoring of CA function by cerebral oxygen index and individualized management strategy with this goal can potentially reduce perioperative ischemic brain injury. The purpose of this study is to explore the influence of the management strategy of monitoring CA function based on regional cerebral oxygen saturation on the postoperative neurological complications of CEA patients.

To compare the safety and efficacy of carotid revascularization performed within 48 hours versus after 14 days in patients with symptomatic carotid stenosis accompanied with MRI-confirmed acute infarction (high signal on diffusion-weighted imaging accompanied by low apparent diffusion coefficient signal) in the responsible vascular territory.

Approximately 20% of strokes originate from the rupture of an atherosclerotic plaque in the carotid artery. Surgical revascularization, i.e. carotid endarterectomy (CEA), is the treatment of choice for patients with a symptomatic carotid stenosis each year about 3,000 procedures are performed in the Netherlands. Currently, two surgical procedures are performed in clinical practice. Most frequently an endarterectomy is performed using a length incision over the artery, followed by a patch plasty (CEAP), in order to reduce the risk of restenosis. As an alternative the eversion technique (ET) was introduced, in which transversal arteriotomy is performed and the plaque is removed from within. After reconstruction with a patch a \>50% restenosis has been described in 6-36% of patients during long-term follow-up. When using the eversion technique this is seen in 1.7-2.5%, while also the risk on adverse events seem to be lower. One of the drivers for atherosclerosis in general is a disturbance of local blood flow. This may lead to turbulence, recirculation and stasis of blood. The subsequent low Wall Shear Stress may lead to the ne formation of plaque that in turn may become instable and cause recurrent ischemic events. Recently, a breakthrough was achieved in the imaging options of flow in the carotid arteries, using Vector Flow Imaging. Using a fully programmable ultrasound machine, over 10,000 frames per second can be captured, in comparison to about 50 in regular ultrasound. This enables the tracking of particles that, after processing will provide the needed flow information. A recent study, comparing flow before and after CEAP has shown that there is significant recirculation after reconstruction. This raises the question whether this would be more optimal after ET, which would support the potential lower incidence of recurrent stenosis.

This study is aimed at patients suffering from carotid atherosclerosis. In the presence of atherosclerosis of the carotid arteries, one of the treatments that can be proposed is carotid endarterectomy, the aim of which is to remove the atherosclerotic plaque that obstructs the carotid artery and therefore increases the risk of developing a stroke. The risk of rupture of these plaques is primarily assessed by anatomical medical imaging: the degree of stenosis (narrowing) that the plaque causes most often informs the decision whether or not to proceed with surgery. However, it is well established that the degree of stenosis is not a very precise decision criterion: some plaques would never have ruptured, while others have ruptured even though no surgical intervention had been performed. It has since been discovered that the degree of inflammation is a much more accurate predictor of future rupture, but there is currently no reliable non-invasive imaging marker to measure plaque inflammation. In this study, the investigators therefore evaluate a new marker, the perfluorocarbon ABL-101, for non-invasive imaging of inflammation in atherosclerotic plaque. To assess the marker's effectiveness in quantifying inflammation in plaque, the plaque will be analyzed microscopically after removal to obtain a more accurate measure of the degree of inflammation. This will enable us to assess the effectiveness of the non-invasive marker injection method versus the more invasive microscopic analysis of the removed plaque. ABL-101 consists of a perfluorocarbon (PFC) emulsion, a liquid mixture in which PFC particles are dispersed. PFCs are chemical compounds containing only carbon and fluorine, and are known for their ability to transport large quantities of oxygen. Totally inert, PFCs cannot be broken down by the body and are eliminated naturally. Due to their small size, these particles are also captured by certain immune system cells and, combined with 19F-MRI, constitute a marker of inflammation.

Postoperative delirium (POD) is a common perioperative complication, which can lead to adverse outcomes. Patients undergoing carotid endarterectomy (CEA) were elderly, complicated with vascular risk factors, cognitive dysfunction, some also had a history of stroke, and the circulation fluctuated greatly during the operation, often resulting in hypoperfusion of cerebral tissue and hypoxia. Therefore, they're the high-risk group of POD. Near-infrared Spectroscopy (NIRS) can continuously and noninvasively monitor local cerebral oxygen saturation (SctO2) to identify the mismatch of oxygen supply and demand in brain tissue. However, for CEA patients, the association between intraoperative SctO2 changes and POD remains unclear. This study intends to explore the association between them and determine the SctO2 threshold for predicting POD. We will monitor SctO2 intraoperatively, follow up and collect data postoperatively.

Patients undergoing carotid endarterectomy may suffer from neurologic deficits (ND) during the carotid cross-clamping due to cerebral hypoperfusion. An associated risk of postoperative stroke incidence is also well established. The aim of this study is to evaluate the predictive factors associated with ND during CEA performed with RA. The perioperative implications of the ND were also evaluated.