View clinical trials related to Carotid Artery Plaque.
Filter by:Stroke is the second leading cause of death in the Western world and the leading cause of major lifelong disability. About 15% of strokes are secondary to thrombosis or embolization of an unstable atheromatous carotid plaque. In these symptomatic patients, the degree of carotid stenosis is correlated with the risk of early recurrence. Patients with stenosis over 70% are therefore offered an endarterectomy, an operation to remove carotid plaque, to prevent future strokes[1]. In asymptomatic patients, the degree of stenosis is a limited predictor, and better risk stratification is required to assess the degree of plaque vulnerability and stroke risk of the patient. The therapeutic decision towards endarterectomy in addition to drug therapy is debated because of a variable and dependent benefit/risk balance for each patient. A number of imaging parameters have been studied: ulceration, heterogeneity, vascularization of the plaque for example, but their place is not well defined [2]. The usual evaluation of carotid stenosis is by conventional Doppler ultrasound with calculation of the degree of stenosis according to the NASCET criteria. For symptomatic stenoses the intervention is recommended when above 70% and is discussed from 50% to 70% of NASCET stenosis degree. For asymptomatic stenoses, the procedure is discussed when above 60% taking into account the patient's life expectancy, the risk of the surgery and the unstable nature of the plaque [2]. Destabilization of the carotid plaque is partially induced by inflammation associated with neo-vascularization. The detection of these new vessels by conventional contrast ultrasound has already shown a distinction between stable and unstable plaques, by the presence or absence of microbubbles in the plaque. However, this assessment is not very precise and only the most vascularized plaques can be detected. Ultrafast ultrasound Imaging is a new ultrasonic Imaging modality that allows detecting low speed flows, a tiny vascular structure within the vessel wall. RESEARCH HYPOTHESIS Plaques neo-vascularization would be more precisely detected and characterized by ultrafast imaging coupled with microbubble injection than conventional ultrasound imaging. A better assessment of plaque instability could improve the selection of patients for carotid endarterectomy and increase the benefit/risk ratio of this preventive surgery.
Stroke is a major cause of death and disability worldwide. Stenotic carotid arteries can lead to stroke if the cause of the stenosis is a vulnerable atherosclerotic plaque. Recent studies reveal that if a patient has a plaque in the carotid artery it is highly probable that he/she will develop plaques in other superficial arteries like the femoral artery. Currently, duplex ultrasound is used to determine the grade of stenosis and is the main criterion for intervention (endarterectomy) planning. However, the stability, or instability of the plaque cannot be determined non-invasively. Photoacoustics is a novel, non-invasive imaging modality that uses pulsed laser light to generate laser induced ultrasound in the absorbing region of the tissue. Photoacoustic imaging provides optical contrast of biological tissue chromophores with an acoustic resolution and imaging depth, which is promising for visualization of plaque composition. The advantage of photoacoustics is the use of multiple wavelengths, since different tissues respond differently to different wavelengths. Hence, non-invasive, in vivo, morphology assessment is a future application of this new modality that would improve diagnosis and clinical decision making. The drawback is the limited penetration depth of the laser light and the signals generated by surrounding tissue. A new, integrated photoacoustic device has been developed that meets all safety requirements and has an improved penetration depth, suitable for imaging of carotid arteries with the aim to distinguish between plaques with different morphology.
While 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging has been used as an early marker of drug efficacy in numerous clinical cardiovascular drug trials, as a glucose analog, its signal in the vasculature lacks inflammatory cell-specificity. Moreover, high background 18F-FDG signals from the myocardium often preclude coronary artery imaging, despite attempts to suppress myocardial tracer uptake by dietary manipulation. These limitations of 18F-FDG for measuring changes in vascular inflammation arising from drug intervention highlight important unmet needs, which might be overcome by using a somatostatin receptor subtype-2 (SST2) PET tracer.
Stroke is a leading cause of death and disability in the United States and around the world. The goal of this work is to develop and test a noninvasive ultrasound-based imaging technology to better identify patients at high risk of stroke so that appropriate and timely intervention may be administered to prevent it.
As of today, no suitable multiparametric predictive method is available to properly estimate stroke risk in patients with carotid artery stenosis. Carotid artery stenosis is one of the proven risk factors of stroke incidence, but the indication of its intervention is merely the grade of stenosis itself. The current international guidelines suggest intervention for asymptomatic patients only with potentially high risk plaques but pharmacological treatment is advised to low risk patients. Unfortunately there is no proven and widely accepted system to distinguish these two categories of patients with carotid artery stenosis. In this project the following parameters will be assessed both in asymptomatic and symptomatic patients: 1, preoperative stroke risk prediction based on comparative analysis of CT angiography (CTA) results of plaque morphology and ultrasound (US) based plaque elastography analysis, 2) intracranial bloodflow will be measured by transcranial Doppler sonography(TCD), 3) presence recent of silent brain ischemia on diffusion weighted imaging (DWI) MR (magnetic resonance), 4) retinal perfusion measurement by optical coherence tomography angiography (OCT). The investigators aim to establish a clinically meaningful and more accurate (than stenosis grade) stroke risk prediction algorithm for asymptomatic carotid stenosis patients based on these parameters.
The purpose of the research is to understand structural plaque abnormalities that make a carotid plaque unstable and brake off (embolize) which would help to predict and treat individuals who are likely to suffer not only classic episodic major strokes but also cognitive impairment.