Dual-energy CT for the assessment of carotid artery stenoses: is this the way forward?

This study sought to determine the frequency of noncircular lumens in patients with significant carotid atherosclerotic disease and to evaluate the effect of noncircular lumens on stenosis measurement derived from angiographic projections. One hundred consecutive patients presenting with an internal carotid artery stenosis of at least 50% were imaged with spiral CT angiography. The transverse morphology of the diseased lumen was assessed on axial images, and the frequency of noncircular lumens was determined. In these cases, maximum intensity projection angiograms were reconstructed in standardized angiographic planes and in a plane selected according to the luminal obliquity, which was chosen to optimize the angiographic representation of the maximal stenosis. North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurements were calculated from the maximum intensity projection images, and differences between values obtained from standard and optimized projections were recorded. Noncircular lumens were observed in 18 of 100 patients and consisted of elliptical and linear transverse profiles. The transverse orientation of the lumen in these cases ranged from +90 degrees to -87 degrees relative to the anteroposterior plane. An increase in the calculated NASCET stenosis was demonstrated when measurements were obtained from angiographic reconstructions obtained in the exact plane of the luminal obliquity compared with standard angiographic projections. As a result, the stenosis severity was upgraded from moderate to severe in 2 patients. Noncircular transverse luminal profiles are not uncommon and may introduce error into NASCET calculations obtained from standard angiographic projections.

One of the great achievements of modern medicine is the successful prevention of stroke and other cardiovascular diseases. Although the incidence of stroke has substantially declined over the last 30 years, ≈200 000 preventable stroke deaths still occur annually in the United States. According to a recent study based on the Greater Cincinnati/Northern Kentucky Stroke Study, annually ≈41 000 strokes in the United States are attributed to extracranial internal carotid artery stenosis. Early revascularization for symptomatic carotid stenosis—that is, in patients with recent ipsilateral stroke or TIA—is well established as effective at preventing ipsilateral stroke. Carotid stenosis in the absence of symptoms is extremely common, but the best treatment is unclear. While 2 randomized trials showed a benefit of carotid endarterectomy (CEA) over antiplatelet therapy with aspirin, the number needed to treat approaches 200. Does aggressive risk factor control change that balance? Population screening for carotid stenosis followed by revascularization is considered to cause net harm. Are complication rates from endarterectomy and stenting now low enough to justify expanding their indications in asymptomatic patients? The National Institute of Neurological Disorders and Stroke (NINDS)–funded CREST-2 trial (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial) is an ambitious attempt to further refine the treatment of asymptomatic carotid stenosis. As one of the largest randomized stroke prevention trials, the first CREST (Carotid Revascularization Endarterectomy Versus Stenting Trial) was designed to compare the safety and efficacy of 2 stroke prevention procedures for carotid artery narrowing—CEA and carotid artery stenting (CAS)—in symptomatic and asymptomatic individuals. Starting in December 2000, this NINDS-funded trial enrolled >2500 patients at 117 sites in the United States and Canada. Because of slow enrollment, the trial took 9 years to complete. In 2010, the results of CREST indicated that the 2 revascularization procedures were equivalent for …

Carotid endarterectomy reduces the risk of stroke in certain patients with recently symptomatic carotid stenosis1 and to a lesser extent inpatients with severe asymptomatic stenosis.2 Screening of patients for inclusion in the randomized controlled trials (RCTs) was usually performed with Doppler ultrasound (DU), but conventional arterial angiography (CAA) was required prior to randomization in the RCTs in symptomatic stenosis1 and prior to surgery in ACAS.2 However, CAA is costly, time-consuming, and can cause stroke. A systematic review of prospective studies of the risks of CAA inpatients with cerebrovascular disease reported a 0.1% risk of death and a 1.0% risk of permanent neurological sequelae.3 More recent studies have reported lower risks in both academic centers and community hospitals,4 but many centers have already adopted a policy of operating on the basis of DU alone.5 The main advantage of DU over CAA is the absence of a procedural risk. However, it should be noted that most studies of the risk of CAA classified all strokes that occurred within 24 hours of CAA as procedural complications. Given that the risk of stroke shortly after presentation with symptomatic carotid stenosis and …

Part One: For the Motion Carotid Disease is Rarely Responsible for Stroke after Coronary Bypass Surgery

Perioperative cerebral and myocardial ischemia and injury in surgical patients having known carotid artery stenosis.

Digital subtraction angiography (DSA) is considered the reference method for the assessment of carotid artery stenosis; however, the procedure is invasive and accompanied by ionizing radiation. Velocity estimation with duplex ultrasound (DUS) is widely used for carotid artery stenosis assessment since no radiation or intravenous contrast is required; however, the method is angle-dependent. Vector concentration (VC) is a parameter for flow complexity assessment derived from the angle independent ultrasound method vector flow imaging (VFI), and VC has shown to correlate strongly with stenosis degree. The aim of this study was to compare VC estimates and DUS estimated peak-systolic (PSV) and end-diastolic velocities (EDV) for carotid artery stenosis patients, with the stenosis degree obtained with DSA. Eleven patients with symptomatic carotid artery stenosis were examined with DUS, VFI, and DSA before and after stent treatment. Compared to DSA, VC showed a strong correlation (r = −0.79, p < 0.001), while PSV (r = 0.68, p = 0.002) and EDV (r = 0.51, p = 0.048) obtained with DUS showed a moderate correlation. VFI using VC calculations may be a useful ultrasound method for carotid artery stenosis and stent patency assessment.

Background: Common angiography or digital subtraction angiography (DSA) is the gold standard protocol for diagnosis of carotid artery stenosis. However, this method has very high delivered X-ray doses to patient and personnel as an invasive diagnostic protocol. The progress of noninvasive or minimally invasive diagnostic techniques like Doppler ultrasonography (DUS), CT angiography (CTA), and MR angiography (MRA) has improved the detection and evaluation of stenosis lesions. The aim of this study was to evaluate the usefulness and accuracy of non-invasive DUS and CTA, attempting in this way to restrict DSA only for final proof of high-grade stenosis. Methods: 25 male patients with carotid artery stenosis were examined with CTA, DUS, and DSA. The lumen diameter of carotid artery was measured and compared with CTA and DUS. The results of CTA and DUS were compared and correlated with DSA results as a reference. Results: Data of lumen diameter measurements in ultrasonography and CTA (for internal and common carotid artery) showed no significant differences between the two methods. Mean internal/common lumen artery in stenosis region was 3.745/5.114 and 3.643/5.000 millimeters for CTA and DUS, respectively. The results (mean ± standard deviation) of moderate to severe carotid stenosis obtained from CTA, DUS, and DSA in stenoses ≥ 50% were 67.8 ± 10.82, 65.6 ± 13.25, and 71.2 ± 11.2 (in percentage), respectively. The Spearman correlations of CTA and DUS results with DSA results were 0.865 and 0.812, respectively. Conclusions: Significant correlations were found in our study between CTA/DSA and DUS/DSA. We showed that the accuracy of CTA and Doppler ultrasonography was appropriate in comparison with DSA results for male patients with carotid stenosis ≥ 50%. We also showed that measurement of PSV could be a good parameter for evaluating carotid stenosis like PSVr in Doppler ultrasonography.

The diagnosis and treatment of asymptomatic and symptomatic patients with carotid artery stenosis.

Prevalence and the Risk Factors for Asymptomatic Carotid Artery Stenosis Among Type II Diabetes Mellitus Patients

Arterial occlusive disease is a systemic phenomenon frequently coexisting in more than one arterial system. Often in one arterial bed disease is manifested with symptoms, in another is asymptomatic. There are only several reports indicating the prevalence of carotid stenosis in patients with peripheral vascular disease. Asymptomatic carotid stenosis is defined as the presence of internal carotid/carotid bifurcation stenotic or occlusive lesions in patients with no signs or symptoms of cerebrovascular disease. Lesions are important causative factors in unheralded stroke. Two factors are particularly important: severity of stenosis and morphologic characteristics of the stenotic plaque. The recent largest completed clinical trial concerning asymptomatic carotid artery stenosis (completed 1995) ACAS (Asymptomatic Carotid Artery Study) established the benefit of surgical treatment vs. best medical treatment. The reduction in relative risk of stroke was 55% in favor of surgery. Population screening for carotid stenosis is inefficient and expensive. The current interest is focused on the efficacy of screening population at risk. The aim of the study was to establish prevalence of asymptomatic carotid artery stenosis in patients with symptomatic lower extremities atherosclerosis. Furthermore, possibility for limiting screening to subgroups of patients concerning risk factors, carotid bruit and severity of lower extremities atherosclerosis, was examined. Over the study period 109 patients with symptomatic lower extremities atherosclerosis underwent routine carotid duplex examinations (on Acuson 128 XP-10) to detect the presence of asymptomatic carotid disease. Indication for hospitalization was pain at rest in 60% of patients, ulcer or gangrene in 25% and claudication in 15%. Patients with a history of previous carotid endarterectomy or symptomatic cerebrovascular disease, patients who underwent emergency operations, and patients with nonatherosclerotic disease were not included in the analysis. Internal carotid stenosis was determined by duplex ultrasound blood flow velocities according to a criterion of ACAS. Plaque morphology was classified according to Gray-Weale as type I (echolucent) to type IV (echogenic). Plaque surface was graded as smooth, irregular and ulcerated. Secondary analysis was performed to find out a subgroup of patients with symptomatic lower extremities atherosclerosis at significant risk for carotid artery stenosis in order to be maximally effective. We examined the relationship of carotid artery stenosis of 60% or grater or occlusion to the 1st degree of lower extremities atherosclerosis (determined by previous vascular surgery, preoperative ankle-systolic blood pressure index, clinical severity of disease); 2. age and gender; 3. risk factors of atherosclerosis (arterial hypertension, diabetes mellitus, hyperlipidaemia, smoking history, and alcohol consumption); and 4. carotid bruit. Data were analyzed using two-way contingency tables and chi 2 test, two-sample Student's test, and multivariate, stepwise logistic regression analysis. According to the criterion of ACAS, forty patients (36.69%) had haemodynamically significant carotid artery stenosis > 60% or occlusion, and 32 patients (29%) carotid artery stenosis > 70% or occlusion. These results confirm that patients with symptomatic lower extremities atherosclerosis are at risk for increased prevalence for simultaneous asymptomatic carotid artery stenosis. Using B-mode we assessed carotid plaque characteristics in a group of 40 patients with asymptomatic 50-99% carotid artery stenosis. Distribution of plaque morphology was as follows: type I (echolucent with thin echogenic cap) in 4 patients (9.30%), type II (substantially echolucent) in 10 (23.26%), type III (dominantly echogenic) in 19 (44.18%), and type IV (homogenous echogenic) in 10 patients (23.26%). Plaque types III and IV were more common in asymptomatic patients, but there was no significant association with fibrous component of plaque. Degree of internal carotid stenosis was unrelated to plaque morphology. Plaque surface was as follows: smooth in 8 patients (18.60%), irregular in 25 (58.14%) and ulcerated in 10 patients (23.26%). Presence of ulcerated surface in 6 plaques (14%) with 50-69% of carotid artery stenosis is worth mentioning because these patients could be a subgroup likely to suffer stroke without warning. Secondary analysis examined the relationship of carotid artery stenosis of 60% or grater or occlusion to different patient's characteristics. By multivariant analysis we found that significant carotid artery stenosis was associated with prior vascular surgery, in patients over 60 years of age, arterial hypertension, ASPI < 0.5, and carotid bruit (results were considered significant if p < 0.05). Probability that various factors influenced the prevalence of carotid artery stenosis was assessed by multivariate stepwise logistic regression analysis. Only carotid bruit was associated with carotid artery stenosis > 60% (t = 0.50; p = 0.01), with sensitivity of 67% and specificity of 56%. Prevalence of asymptomatic carotid artery stenosis in patients with lower extremities atherosclerosis is relatively high. Limiting screening of specific subgroups for any demographic or medical characteristics is ineffective. Screening for asymptomatic carotid artery stenosis is indicated in all patients with lower extremities atherosclerosis except in whom prophylactic carotid endarterectomy is not recommended because of comorbid disease or extreme age.

Two articles were published in February 2001 that will have a significant impact on our understanding of human development, the pathogenesis of many human diseases, and the discovery of new therapies for many disorders.1 2 These articles deal with the mapping of the human genome. Two different entities, one a publicly traded company (Celera) and the other the Human Genome Project (HGP, sponsored and funded by NIH), published somewhat different versions of the human genome. The HGP began in 1990 (although extensive sequencing of the human genome began in 1995) and cost approximately $3 billion, while the Celera effort began in 1998.1 2 The HGP involved multiple laboratories in the United States and abroad. The 2 projects produced maps that differ from each other in terms of completeness, order of some genetic markers, and the ability to search the database for specific DNA sequences. A comparison of some features of both projects is in Table 1⇓. The challenge of sequencing the 3 billion base pairs of the human genome required the development of unique tools and approaches. Celera constructed a facility capable of high-throughput sequencing at a rate of 175 000 reads per day and conducted sequencing 24 hours a day, 7 days a week. The HGP divided the sequencing task among several large laboratories with demonstrated expertise in large-scale DNA sequencing. The strategy employed by the HGP focused on subcloning the human genome into bacterial artificial chromosomes (BAC), which were then sequenced and properly arranged.1 Each BAC could hold an insert of 150 000 bases on average. Celera used a shotgun whole genome approach to sequencing, which involved generating many small, random fragments of DNA for sequencing.2 After the sequence was determined, advanced computational algorithms combined with publicly available mapping and sequence information …

Friday, September 28, 2018 10:30 AM–12:00 PM abstracts: complications of cervical spine surgery: 161. Incidence of postoperative stroke after anterior cervical discectomy and fusion in patients who have carotid stenosis

Carotid artery stenting versus endarterectomy for carotid stenosis – Authors' reply

Stroke ranks as the third leading cause of death in the United States. It is now estimated that there are more than 700 000 incident strokes annually and 4.4 million stroke survivors.1 2 The economic burden of stroke was estimated by the American Heart Association to be $51 billion (direct and indirect costs) in 1999.3 Despite the advent of treatment of selected patients with acute ischemic stroke with tissue plasminogen activator and the promise of other experimental therapies, the best approach to reducing the burden of stroke remains prevention.4 5 High-risk or stroke-prone individuals can be identified and targeted for specific interventions.6 This is important because epidemiological data suggest a substantial leveling off of prior declines in stroke-related mortality and a possible increase in stroke incidence.7 8 The Stroke Council of the American Heart Association formed an ad hoc writing group to provide a clear and concise overview of the evidence regarding various established and potential stroke risk factors. The writing group was chosen based on expertise in specific subject areas, and it used literature review, reference to previously published guidelines, and expert opinion to summarize existing evidence and formulate recommendations (Table 1⇓). View this table: Table 1. Levels of Evidence and Grading of Recommendations As given in Tables 2 through 4⇓⇓⇓, risk factors or risk markers for a first stroke were classified according to potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented, less well documented).5 The tables give the estimated prevalence, population attributable risk, relative risk, and risk reduction with treatment for each factor when known. Population attributable risk reflects the proportion of ischemic strokes in the population that can be attributed to a particular risk factor and is given by the formula 100×[prevalence(relative risk−1)/prevalence(relative risk−1)+1]). …

BACKGROUND Carotid artery stenting is an alternative to carotid endarterectomy for the treatment of atherosclerotic carotid artery stenosis. This review updates a previous version first published in 1997 and subsequently updated in 2004, 2007, and 2012. OBJECTIVES To assess the benefits and risks of stenting compared with endarterectomy in people with symptomatic or asymptomatic carotid stenosis. SEARCH METHODS We searched the Cochrane Stroke Group Trials Register (last searched August 2018) and the following databases: CENTRAL, MEDLINE, Embase, and Science Citation Index to August 2018. We also searched ongoing trials registers (August 2018) and reference lists, and contacted researchers in the field. SELECTION CRITERIA Randomised controlled trials (RCTs) comparing stenting with endarterectomy for symptomatic or asymptomatic atherosclerotic carotid stenosis. In addition, we included RCTs comparing carotid artery stenting with medical therapy alone. DATA COLLECTION AND ANALYSIS One review author selected trials for inclusion, assessed trial quality and risk of bias, and extracted data. A second review author independently validated trial selection and a third review author independently validated data extraction. We calculated treatment effects as odds ratios (OR) and 95% confidence intervals (CI), with endarterectomy as the reference group. We quantified heterogeneity using the I² statistic and used GRADE to assess the overall certainty of evidence. MAIN RESULTS We included 22 trials involving 9753 participants. In participants with symptomatic carotid stenosis, compared with endarterectomy stenting was associated with a higher risk of periprocedural death or stroke (the primary safety outcome; OR 1.70, 95% CI 1.31 to 2.19; P < 0.0001, I² = 5%; 10 trials, 5396 participants; high-certainty evidence); and periprocedural death, stroke, or myocardial infarction (OR 1.43, 95% CI 1.14 to 1.80; P = 0.002, I² = 0%; 6 trials, 4861 participants; high-certainty evidence). The OR for the primary safety outcome was 1.11 (95% CI 0.74 to 1.64) in participants under 70 years old and 2.23 (95% CI 1.61 to 3.08) in participants 70 years old or more (interaction P = 0.007). There was a non-significant increase in periprocedural death or major or disabling stroke with stenting (OR 1.36, 95% CI 0.97 to 1.91; P = 0.08, I² = 0%; 7 trials, 4983 participants; high-certainty evidence). Compared with endarterectomy, stenting was associated with lower risks of myocardial infarction (OR 0.47, 95% CI 0.24 to 0.94; P = 0.03, I² = 0%), cranial nerve palsy (OR 0.09, 95% CI 0.06 to 0.16; P < 0.00001, I² = 0%), and access site haematoma (OR 0.32, 95% CI 0.15 to 0.68; P = 0.003, I² = 27%). The combination of periprocedural death or stroke or ipsilateral stroke during follow-up (the primary combined safety and efficacy outcome) favoured endarterectomy (OR 1.51, 95% CI 1.24 to 1.85; P < 0.0001, I² = 0%; 8 trials, 5080 participants; high-certainty evidence). The rate of ipsilateral stroke after the periprocedural period did not differ between treatments (OR 1.05, 95% CI 0.75 to 1.47; P = 0.77, I² = 0%). In participants with asymptomatic carotid stenosis, there was a non-significant increase in periprocedural death or stroke with stenting compared with endarterectomy (OR 1.72, 95% CI 1.00 to 2.97; P = 0.05, I² = 0%; 7 trials, 3378 participants; moderate-certainty evidence). The risk of periprocedural death or stroke or ipsilateral stroke during follow-up did not differ significantly between treatments (OR 1.27, 95% CI 0.87 to 1.84; P = 0.22, I² = 0%; 6 trials, 3315 participants; moderate-certainty evidence). Moderate or higher carotid artery restenosis (50% or greater) or occlusion during follow-up was more common after stenting (OR 2.00, 95% CI 1.12 to 3.60; P = 0.02, I² = 44%), but the difference in risk of severe restenosis was not significant (70% or greater; OR 1.26, 95% CI 0.79 to 2.00; P = 0.33, I² = 58%; low-certainty evidence). AUTHORS' CONCLUSIONS Stenting for symptomatic carotid stenosis is associated with a higher risk of periprocedural stroke or death than endarterectomy. This extra risk is mostly attributed to an increase in minor, non-disabling strokes occurring in people older than 70 years. Beyond the periprocedural period, carotid stenting is as effective in preventing recurrent stroke as endarterectomy. However, combining procedural safety and long-term efficacy in preventing recurrent stroke still favours endarterectomy. In people with asymptomatic carotid stenosis, there may be a small increase in the risk of periprocedural stroke or death with stenting compared with endarterectomy. However, CIs of treatment effects were wide and further data from randomised trials in people with asymptomatic stenosis are needed.