Project description:Symptomatic carotid artery disease is a significant cause of ischemic stroke, and these patients are at high risk for recurrent vascular events. Patients with symptoms of stroke or transient ischemic attack attributable to a significantly stenotic vessel (70-99% luminal narrowing) should be treated with intensive medical therapy. Intensive medical therapy is a combination of pharmacologic and lifestyle interventions consistent with best-known practices as follows: initiation of antiplatelet agent or anticoagulation if medically indicated, high potency statin medication, blood pressure control with goal blood pressure of greater than 140/90, Mediterranean-style diet, exercise, and smoking cessation. Further, patients who have extracranial culprit lesions should be considered for revascularization with either carotid endarterectomy or carotid angioplasty and stenting depending on several factors including the patient's anatomy, age, gender, and procedural risk. Based on current evidence, patients with symptomatic intracranial stenosis should be managed with intensive medical therapy, including the use of dual antiplatelet therapy with aspirin and clopidogrel for the first 90 days following the ischemic event. While the literature has shown a stronger benefit of revascularization of extracranial symptomatic disease among certain subgroups of patients with greater than 70% stenosis, there is less benefit from revascularization with endarterectomy in patients with moderate stenosis of 50-69% if the surgeon's risk of perioperative stroke or death rate is greater than 6%.
Project description:With the aging of the general population and the availability of noninvasive imaging studies, carotid artery stenosis is a disease commonly seen in general medical practice. Differentiation between symptomatic and asymptomatic disease is critical to the treatment course because the natural history differs markedly between them. Antiplatelet therapy and aggressive treatment of vascular risk factors are the mainstays of medical therapy. Class I evidence shows that carotid endarterectomy (CEA) is effective in preventing ipsilateral ischemic events in patients with symptomatic moderate- and high-grade stenosis. The procedure is also effective in selected patients with asymptomatic stenosis, but the benefit is marginal. In the past decade, carotid angioplasty and stenting has been proposed as a valid alternative to CEA. Currently, it is unclear whether carotid angioplasty and stenting is as safe as CEA in patients with carotid artery stenosis who need invasive treatment. Large clinical trials are under way to answer this question.
Project description:Various surgical treatments are available for occlusive subclavian and common carotid artery diseases. Nevertheless, to date, when cerebral endovascular treatment is utilized, revascularization via direct surgery may be required. This study reported five symptomatic cases of revascularization for CCA and SCA occlusive and stenotic lesions that were expected to be challenging to treat with endovascular treatment. We performed subclavian artery-common carotid artery or internal carotid artery bypass using artificial blood vessels or saphenous vein grafts in five patients with subclavian steal syndrome, symptomatic common carotid artery occlusion, and severe proximal common carotid artery stenosis. In this study, good bypass patency was achieved in all five cases. Although there were no intraoperative complications, one patient had a postoperative lymphatic leak. Moreover, there was no recurrence of stroke during postoperative follow-up for an average of 2 years. Conclusively, subclavian artery-common carotid artery bypass can be an effective surgical treatment for common carotid artery occlusion, proximal common carotid artery stenosis, and subclavian artery occlusion.
Project description:Failure of the blood-brain barrier (BBB) is a critical event in the development and progression of diseases such as acute ischemic stroke, chronic ischemia or small vessels disease that affect the central nervous system. It is not known whether BBB breakdown in subjects with chronic carotid artery stenosis can be restrained with postoperative recovery of cerebral perfusion. The aim of the study was to assess the short-term effect of internal carotid artery stenting on basic perfusion parameters and permeability surface area-product (PS) in such a population. Forty subjects (23 males) with stenosis of >70% within a single internal carotid artery and neurological symptoms who underwent a carotid artery stenting procedure were investigated. Differences in the following computed tomography perfusion (CTP) parameters were compared before and after surgery: global cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP) and PS. PS acquired by CTP is used to measure the permeability of the BBB to contrast material. In all baseline cases, the CBF and CBV values were low, while MTT and TTP were high on both the ipsi- and contralateral sides compared to reference values. PS was approximately twice the normal value. CBF was higher (+6.14%), while MTT was lower (-9.34%) on the contralateral than on the ipsilateral side. All perfusion parameters improved after stenting on both the ipsilateral (CBF +22.66%; CBV +18.98%; MTT -16.09%, TTP -7.62%) and contralateral (CBF +22.27%, CBV +19.72%, MTT -14.65%, TTP -7.46%) sides. PS decreased by almost half: ipsilateral -48.11%, contralateral -45.19%. The decline in BBB permeability was symmetrical on the ipsi- and contralateral sides to the stenosis. Augmented BBB permeability can be controlled by surgical intervention in humans.
Project description:Identification of novel pathophysiological mechanisms of carotid artery disease at systemic level by studying the gene expression profile of peripheral blood of affected patients with respect to control subjects.
Project description:BackgroundSignificant genetic association has been found in patients with severe carotid artery stenosis (CAS). The present study wished to investigate if metabolites may also act as biomarkers for CAS.MethodsConsecutive patients with at least one carotid artery stenosis > = 60% on cerebral angiography were prospectively recruited from May 2007 to January 2016. Normal controls were recruited from outpatient clinic who had no stroke and coronary artery disease (CAD) history, and the brain magnetic resonance or computed tomographic angiography showed bilateral CAS < 30%. Risk factor profile, clinical characteristics, age, and clinical features were recorded. All subjects were male, and none had diabetes. 1H-NMR spectroscopy-based metabolomics analysis was carried out for plasma samples.ResultsTotally, 130 male subjects were recruited. Age had no significant difference between the controls and CAS group (60.2 ± 5.9 vs. 63.3 ± 6.0, p = 0.050). The CAS group had significantly higher frequency of CAD, hypertension, smoking and alcohol but lower body mass index than the controls (p < 0.05). The laboratory tests showed CAS group had significantly higher level of homocysteine but lower levels of cholesterol, high-density lipoprotein and hemoglobin than the controls (p < 0.05). The 1H-NMR based plasma metabolomics analysis indicated that choline was significantly lower in CAS patients. The VIP values of lipids were greater than 1.0, which were considered significantly different.ConclusionsOur results suggest homocysteine, choline and lipids in association with traditional risk factors may be involved in the pathogenesis of CAS. Diet adjustment to control homocysteine, choline and lipids may be helpful for the prevention of CAS.
Project description:BackgroundPopulation-based studies have estimated that about 15% of ischemic strokes are caused by large-vessel cerebrovascular disease. We determined the types of large-vessel atherosclerosis responsible for ischemic strokes in a population-based stroke study.MethodsPatients with first-ever or recurrent ischemic stroke in the Greater Cincinnati area were identified during 2005 at all local hospitals. Study physicians assigned ischemic stroke subtypes. Overall event rates and incidence rates for first-ever events were calculated, and age-, race- and sex-adjusted to the 2000 US population.ResultsThere were 2,204 ischemic strokes, including 365 strokes of large-vessel subtype (16.6% of all ischemic strokes). Extracranial internal carotid artery (ICA) stenosis was associated with 8.0% of all ischemic strokes, while extracranial ICA occlusion and intracranial atherosclerosis were each associated with 3.5% of strokes. The annual rate of first-ever and recurrent stroke attributed to extracranial ICA was 13.4 (11.4-15.4) per 100,000 persons. We conservatively estimate that about 41,000 strokes may be attributed to extracranial ICA stenosis annually in the United States.ConclusionsLarge-vessel atherosclerosis is an important cause of stroke, with extracranial ICA stenosis being significantly more common than extracranial ICA occlusion or intracranial atherosclerotic disease.
Project description:ObjectivePatients with contralateral carotid occlusion (CCO) have been excluded from randomized clinical trials because of a deemed high risk for adverse neurologic outcomes with carotid endarterectomy (CEA). Evidence for this rationale is limited and conflicting. Therefore, we aimed to compare outcomes after CEA between patients with and without CCO and varying degrees of contralateral carotid stenosis (CCS).MethodsWe identified patients undergoing CEA from 2003 to 2015 in the Vascular Study Group of New England (VSGNE) registry. Patients were stratified by preoperative symptom status and presence of CCO. Multivariable analysis was used to account for differences in demographics and comorbidities. Our primary outcome was 30-day stroke/death risk.ResultsOf 15,487 patients we identified who underwent CEA, 10,377 (67%) were asymptomatic. CCO was present in 914 patients, of whom 681 (75%) were asymptomatic. Overall, the 30-day stroke/death was 2.0% for symptomatic patients (CCO: 2.6%) and 1.1% for asymptomatic patients (CCO: 2.3%). After adjustment, including symptom status, CCO was associated with higher 30-day stroke/death (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.4-3.3; P = .001), any in-hospital stroke (OR, 2.8; 95% CI, 1.7-4.6; P < .001), in-hospital ipsilateral stroke (OR, 2.2; 95% CI, 1.2-4.0; P = .02), in-hospital contralateral stroke (OR, 5.1; 95% CI, 2.2-11.4; P < .001), and prolonged length of stay (OR, 1.6; 95% CI, 1.3-1.9; P < .001). CCS of 80% to 99% was only associated with a prolonged length of stay (OR, 1.3; 95% CI, 1.1-1.6; P = .01), not with in-hospital stroke. Neither CCO nor CCS was associated with 30-day mortality.ConclusionsAlthough CCO increases the risk of 30-day stroke/death, in-hospital strokes, and prolonged length of stay after CEA, the 30-day stroke/death rates in symptomatic and asymptomatic patients with CCO remain within the recommended thresholds set by the 14 societies' guideline document. Thus, CCO should not qualify as a high-risk criterion for CEA. Moreover, there is no evidence that patients with CCO have lower stroke/death rates after carotid artery stenting than after CEA. We believe that CEA remains a valid and safe option for patients with CCO and that CCO should not be applied as a criterion to promote carotid artery stenting per se.
Project description:ObjectiveWe have shown that almost 50% of patients with asymptomatic carotid stenosis (ACS) will demonstrate cognitive impairment. Recent evidence has suggested that cerebral hypoperfusion is an important cause of cognitive impairment. Carotid stenosis can restrict blood flow to the brain, with consequent cerebral hypoperfusion. In contrast, cross-hemispheric collateral compensation through the Circle of Willis, and cerebrovascular vasodilation can also mitigate the effects of flow restriction. It is, therefore, critical to develop a clinically relevant measure of net brain perfusion in patients with ACS that could help in risk stratification and in determining the appropriate treatment. To determine whether ACS results in cerebral hypoperfusion, we developed a novel approach to quantify interhemispheric cerebral perfusion differences, measured as the time to peak (TTP) and mean transit time (MTT) delays using perfusion-weighted magnetic resonance imaging (PWI) of the whole brain. To evaluate the utility of using clinical duplex ultrasonography (DUS) to infer brain perfusion, we also assessed the relationship between the PWI findings and ultrasound-based peak systolic velocity (PSV).MethodsStructural and PWI of the brain and magnetic resonance angiography of the carotid arteries were performed in 20 patients with ≥70% ACS. DUS provided the PSV, and magnetic resonance angiography provided plaque geometric measures at the stenosis. Volumetric perfusion maps of the entire brain from PWI were analyzed to obtain the mean interhemispheric differences for the TTP and MTT delays. In addition, the proportion of brain volume that demonstrated a delay in TTP and MTT was also measured. These proportions were measured for increasing severity of perfusion delays (0.5, 1.0, and 2.0 seconds). Finally, perfusion asymmetries on PWI were correlated with the PSV and stenosis features on DUS using Pearson's correlation coefficients.ResultsOf the 20 patients, 18 had unilateral stenosis (8 right and 10 left) and 2 had bilateral stenoses. The interhemispheric (left-right) TTP delays measured for the whole brain volume identified impaired perfusion in the hemisphere ipsilateral to the stenosis in 16 of the 18 patients. More than 45% of the patients had had ischemia in at least one half of their brain volume, with a TTP delay >0.5 second. The TTP and MTT delays showed strong correlations with PSV. In contrast, the correlations with the percentage of stenosis were weaker. The correlations for the PSV were strongest with the perfusion deficits (TTP and MTT delays) measured for the whole brain using our proposed algorithm (r = 0.80 and r = 0.74, respectively) rather than when measured on a single magnetic resonance angiography slice as performed in current clinical protocols (r = 0.31 and r = 0.58, respectively).ConclusionsInterhemispheric TTP and MTT delay measured for the whole brain using PWI has provided a new tool for assessing cerebral perfusion deficits in patients with ACS. Carotid stenosis was associated with a detectable reduction in ipsilateral brain perfusion compared with the opposite hemisphere in >80% of patients. The PSV measured at the carotid stenosis using ultrasonography correlated with TTP and MTT delays and might serve as a clinically useful surrogate to brain hypoperfusion in these patients.