Asymptomatic carotid artery stenosis and the risk of ischemic stroke according to subtype in patients with clinical manifest arterial disease

The risk of ischemic events increased in patients with asymptomatic carotid stenosis with decreased cerebrovascular reserve

Identifying high-risk patients with asymptomatic carotid stenosis (ACS) is necessary regardless of whether intensive medical therapy or aggressive treatment is applied. In order to assess the relationship between cerebrovascular reserve (CVR) measured by perfusion CT with inhalation of CO2and the risk of ischemic events in ACS, this long-term follow-up study was conducted. Forty-five patients with ACS who underwent the examination of CVR measured by perfusion CT with inhalation of CO2were collected and followed-up for at least 5 years. The primary end point was the occurrence of ipsilateral cerebral ischemic events. HRs and their 95% CI were calculated by Kaplan-Meier survival analysis and Cox regression models. The mean follow-up time was 68.7±10.7 months (40.0–84.0 months). 13 (28.9%) ipsilateral ischemic events were observed. The annual risk of ipsilateral ischemic events was 4.8%. Kaplan-Meier survival analysis and univariate Cox regression analysis indicated that patients with less CVR experienced more ischemic events (p=0.006 and p=0.013, respectively), which was confirmed by multiple Cox regression analysis (p=0.012). CVR measured by perfusion CT may potentially be the factor which can predict the risk of ipsilateral ischemic events in patients with ACS. Multidisciplinary management is necessary for these high-risk patients.

Current smoking is associated with extracranial carotid atherosclerotic stenosis but not with intracranial large artery disease

Background

Accumulating evidence has shown that cigarette smoking is an important risk factor for ischemic stroke. However, it is not clear about the potential mechanisms through which cigarette smoking affects stroke risk. In the study, we aimed to investigate the relationship between cigarette smoking and the occurrence of extracranial (ECAS) and intracranial atherosclerotic stenosis (ICAS).

Methods

We analyzed patients enrolled in the Chinese intracranial atherosclerosis (CICAS), which was a prospective, multicenter, hospital-based cohort study. Smoking status was classified into never, former and current smoking. For those patients with current smoking, data on time duration (year) and extent (the number of cigarette smoked per day) was recorded and pack year of smoking was calculated. ICAS was evaluated with 3-dimentional time-of-flight MRA and ECAS was evaluated with cervical ultrasonography or contrast-enhanced MRA. Multivariable Logistic regression was performed to identify the association between smoking status and the occurrence of ECAS and ICAS.

Results

A total of 2656 patients (92.7%) of acute ischemic stroke and 208 (7.3%) of transient ischemic attack were analyzed. The mean age was 61.9 ± 11.2 and 67.8% were male. There were 141 (4.9%) patients had only ECAS, 1074 (37.5%) had only ICAS, and 261 (9.1%) had both ECAS and ICAS. Current smoking was significantly associated with the occurrence of ECAS (adjusted OR = 1.47, 95% CI = 1.09–1.99, P < 0.01). In addition, with 1 year of smoking increment, the risk of ECAS increased by 1.1% (adjusted OR = 1.011; 95% CI = 1.003–1.019; P = 0.005); with one cigarette smoked per day increment, the risk of ECAS increased by 1.0% (adjusted OR = 1.010; 95% CI = 1.001–1.020; P = 0.03); and with one pack year of smoking increment, the risk of ECAS increased by 0.7% (adjusted OR = 1.007; 95% CI = 1.002–1.012; P < 0.01). However, no significant association was found between smoking status and the occurrence of ICAS.

Conclusion

A dose–response relationship was identified between cigarette smoking and the occurrence of ECAS, but not ICAS. Further studies on molecular mechanisms were warranted.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-017-0873-7) contains supplementary material, which is available to authorized users.

Carotid Artery Stenting and Blood-Brain Barrier Permeability in Subjects with Chronic Carotid Artery Stenosis

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.

Asymptomatic carotid stenosis: Medicine alone or combined with carotid revascularization

Two positive randomized trials established carotid endarterectomy (CEA) as a superior treatment to medical management alone for the treatment of asymptomatic carotid artery stenosis. However, advances in medical therapy have led to an active and spirited debate about the best treatment for asymptomatic carotid stenosis. The Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis (CREST 2) trial aims to better define the best treatment for the average patient with severe asymptomatic carotid stenosis. Enrollment in the trial may be hampered by strong opinions on either side of the debate. It is important to realize that equipoise exists and that neither the old data on CEA nor the new data on optimal medical therapy provide a rigorous answer. The assumption that medical therapy has already been proven superior to revascularization procedures may hinder both enrollment in the trial and technical advancements in revascularization procedures.

Anesthesia for Patients with Peripheral Vascular Disease and Cardiac Dysfunction

Patients with vascular disease and cardiac dysfunction present particular challenges to the anesthesiologist. They are hemodynamically brittle, at high risk of morbidity and mortality during surgery, and often carry additional comorbidities that increase their complexity and risk. Those with peripheral vascular disease should be assumed to have coronary artery disease and tend to have other systemic vascular problems. Poor cardiac function further worsens perfusion in an already compromised peripheral vascular system. Care of these patients requires judicious monitoring, an anesthetic that optimizes hemodynamic function, and avoidance of particularly likely complications such as perioperative myocardial ischemia, stroke, and bleeding.

Reciprocal regulation of eNOS, H2S and CO-synthesizing enzymes in human atheroma: Correlation with plaque stability and effects of simvastatin

The molecular and cellular mechanisms underlying plaque destabilization remain obscure. We sought to elucidate the correlation between NO, H₂S and CO-generating enzymes, nitro-oxidative stress and plaque stability in carotid arteries. Carotid atherosclerotic plaques were collected from 62 patients who had undergone endarterectomy due to internal artery stenosis. Following histological evaluation the plaques were divided into stable and unstable ones. To investigate the impact of simvastatin we divided patients with stable plaques, into those receiving and to those not receiving simvastatin. Expression and/or levels of p-eNOS/eNOS, pAkt/t-Akt, iNOS, cystathionine beta synthase (CBS), cystathionine gamma lyase (CSE), heme oxygenase-1(HO-1), soluble guanyl cyclase sGCα1, sGCβ1, NOX-4 and HIF-1α were evaluated. Oxidative stress biomarkers malondialdehyde (MDA) and nitrotyrosine (NT) were measured. NT levels were decreased in stable plaques with a concomitant increase of eNOS phosphorylation and expression and Akt activation compared to unstable lesions. An increase in HIF-1α, NOX-4, HO-1, iNOS, CBS and CSE expression was observed only in unstable plaques. 78% of patients under simvastatin were diagnosed with stable plaques whereas 23% of those not receiving simvastatin exhibited unstable plaques. Simvastatin decreased iNOS, HO-1, HIF-1α and CSE whilst it increased eNOS phosphorylation. In conclusion, enhanced eNOS and reduced iNOS and NOX-4 were observed in stable plaques; CBS and CSE positively correlated with plaque vulnerability. Simvastatin, besides its known effect on eNOS upregulation, reduced the HIF-1α and its downstream targets. The observed changes might be useful in developing biomarkers of plaque stability or could be targets for pharmacothepary against plaque vulnerability.

Carotid stenosis in women: time for a reappraisal

The treatment approach for patients with internal carotid artery stenosis is receiving increased scrutiny. Major advances in optimal medical therapy have been associated with a declining stroke rate for symptomatic and asymptomatic patients with carotid stenosis. Customising treatment according to gender is worthy of consideration, since earlier clinical trials showed reduced benefit with carotid endarterectomy in women compared to men. In this review, clinical trial results in women are summarised, studies pertaining to carotid plaque imaging in men and women are discussed and new clinical trials are identified. Finally, the rationale for a women's carotid trial is provided.

The urgent need for contemporary clinical trials in patients with asymptomatic carotid stenosis

Asymptomatic extracranial internal carotid artery atherosclerotic stenosis increases with age and is more common in men. Studies performed more than 2 decades ago showed that carotid endarterectomy reduced the rate of stroke in carefully selected patients with asymptomatic carotid stenosis compared with medical therapy in the long term. Those trials were completed more than 20 years ago and with advances in the treatment of atherosclerotic disease, the question has been raised to as to whether endarterectomy is still of value for patients with asymptomatic narrowing. Perioperative risk of carotid revascularization procedures has also declined. Due to improvements in both medical and surgical treatments for carotid artery stenosis, it is timely to reevaluate the efficacy of carotid intervention relative to medical treatment for patients with asymptomatic stenosis.

Long-Term Outcomes of Carotid Artery Stenting in Clinical Practice

Background—

There is a lack of long-term data and data outside of controlled clinical trials in carotid artery stenting. Thus, we sought to evaluate the long-term effectiveness in stroke prevention by carotid artery stenting in a large number of patients in a real-world setting.

Methods and Results—

The present work represents an all-comer registry with a strict, prospectively designed, follow-up protocol, including an independent pre- and postprocedural neurological assessment. Between November 1999 and March 2015, 1000 procedures in 901 patients were consecutively performed in a single center. Mean age was 71±9 years, and symptomatic stenosis was present in 262 patients (29.1%). The population was also characterized by a high comorbidity: 289 patients (32.1%) would have been excluded according to the CREST protocol (Carotid Revascularization Endarterectomy Versus Stent Trial). The median length of follow-up was 5.5 (interquartile range, 2.6–7.9) years and complete in 93% of the patients. The rate of the primary end point (composite of stroke, death, and myocardial infarction [major adverse cardiac or cerebrovascular event] by day 30 plus ipsilateral stroke beyond 30 days) was 6.9% (9.9% in symptomatic versus 5.7% in asymptomatic patients; P =0.03). The rate was higher in CREST ineligible than in CREST eligible patients (11.4% versus 4.9%; P =0.001).

Conclusions—

Long-term stroke prevention by carotid artery stenting is effective in experienced centers. A high percentage of patients who would have been excluded from controlled clinical trials undergoes carotid artery stenting in daily clinical practice. However, these patients have a substantially higher risk for an acute major adverse cardiac or cerebrovascular event.

Perfusion computed tomography: 4 cm versus 8 cm coverage size in subjects with chronic carotid artery stenosis

OBJECTIVE

The impact of coverage size on global cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and time to peak (TTP) parameters has not been investigated in patients with chronic carotid artery stenosis.

METHODS

63 patients with stenosis of >70% within a single internal carotid artery and neurological symptoms were randomly assigned to two well-matched groups. Differences in CT perfusion scan over a 4 cm or 8 cm range of the brain were compared between the two groups.

RESULTS

The CBF and CBV values were higher in the 4 cm coverage size than in the 8 cm coverage size (by 14.7 and 10.7% on the ipsilateral side and 17.2 and 7.8% on the contralateral side, respectively; all p < 0.001). The MTT value was higher in the 4 cm coverage size than in the 8 cm coverage size on the ipsilateral side (9.6%; p < 0.001). There was no difference between MTT values in the contralateral size. There were no differences between TTP values on the ipsilateral and contralateral sides. The relative indices rMTT and rTTP were higher in the 4 cm coverage size than in the 8 cm coverage size (8.2%, p < 0.001, and 1.1%, p < 0.005, respectively).

CONCLUSION

Absolute CBF and CBV values and relative rMTT and rTTP indices in patients with low CBF and low CBV are highly dependent on coverage size. We recommend using a 4 cm coverage size to assess global cerebral perfusion parameters owing to better accuracy and quicker post-processing.

ADVANCES IN KNOWLEDGE

To the best of our knowledge, this is the first article to compare the influence of 4 cm vs 8 cm coverage size on cerebral perfusion parameters such as CBF, CBV, MTT and TTP in subjects with chronic carotid artery stenosis.

Simultaneous Bilateral Carotid Stenting for Symptomatic Bilateral High-Grade Carotid Stenosis: A Retrospective Clinical Investigation

Background

This retrospective clinical investigation aimed to evaluate the short-term effectiveness and safety of SBCAS for symptomatic bilateral high-grade CS.

Material/Methods

From 2009 to 2014, 145 patients were recruited. Among them, 70 underwent SBCAS, and other 75 patients underwent SAMM and served as controls. The immediate postprocedural complications and postprocedural neurological evaluation, as well as restenosis at 6-month and 1-year follow-ups in the SBCAS group are reported. Additionally, baseline risk factors for ischemic stroke, adverse effects of drugs, and outcomes at 30-day, 6-month, and 1-year follow-ups were compared between the 2 groups.

Results

Our data did not reveal significant differences between the 2 groups in baseline risk factors for ischemic stroke. In the SBCAS group, both HPS (5.7%) and HD (40%) occurred, but they were not very severe, and no patients had postprocedural neurological deficit. Moreover, restenosis only occurred in 3 patients at 3 stent placement sites (4.3%) at 1-year follow-up. Adverse effects of drugs did not occur in SBCAS group, but adverse effects of Bayer aspirin and Lipitor occurred in 4 patients (5.4%) and 18 patients (24.3%), respectively, at 6-month follow-up in the control group. Furthermore, there were significant differences in outcomes between the 2 groups at 30-day, 6-month, and 1-year follow-ups, in that NIHSS, CS ratio, and incidence of endpoint events, as well as 1-year cumulative probability of endpoint events, were all lower in the SBCAS group than in the control group (p<0.05).

Conclusions

Compared to SAMM, we found that SBCAS was more effective and safer for symptomatic bilateral high-grade CS.

Intervention versus Aggressive Medical Therapy for Cognition in Severe Asymptomatic Carotid Stenosis

BACKGROUND AND PURPOSE

Asymptomatic carotid stenosis of ≥70% increases the incidence of microembolism and/or chronic hypoperfusion, which may consequently impair neurocognition and brain connections. We sought controlled evidence for any cognitive benefit of aggressive medical therapy and combined carotid revascularization.

MATERIALS AND METHODS

Patients with asymptomatic, unilateral, ≧70% stenosis of the extracranial ICA chose either aggressive medical therapy alone or in combination with carotid artery stent placement in this nonrandomized controlled study. They were examined with a battery of neuropsychological tests, structural MR imaging, DTI, and resting-state fMRI before and 3 months after treatment.

RESULTS

Forty patients were included with 15 in the medical group and 25 in the stent-placement group. Among them, 13 and 21 in the respective groups completed neuroimaging follow-up. The baseline characteristics and the changes in cognitive performance during 3 months showed no differences between treatment groups. Nevertheless, compared with the medical group, the stent-placement group showed subjective dizziness alleviation (P = .045) and a small increase in fractional anisotropy at the splenium of the corpus callosum and the posterior periventricular white matter ipsilateral to carotid artery stent placement. Moreover, only the stent-placement group showed interval improvement in immediate memory and visuospatial performance, which was accompanied by an increase of functional connectivity at the insular cortex of the dorsal attention network and the medial prefrontal cortex of the default mode network.

CONCLUSIONS

Both aggressive medical therapy alone and combined carotid revascularization in ≧70% asymptomatic carotid stenosis similarly preserved cognition during 3-month follow-up, though the latter had the potential for dizziness alleviation and cognitive and connectivity enhancement.

Stroke due to large vessel atherosclerosis: Five new things

Purpose of review

Extracranial (EC) and intracranial (IC) large vessel atherosclerosis account for about 20% of ischemic stroke cases. In recent years, new treatments have emerged for treatment of both EC and IC disease.

Recent findings

The stroke rate in patients with carotid stenosis is decreasing with modern medical therapy. For patients with asymptomatic stenosis, the stroke rate is likely <1% per year. Some subsets of patients with symptomatic carotid disease benefit less from revascularization, and medical management can be considered in these patients. A second clinical trial has confirmed that aggressive medical management is the treatment of choice for IC atherosclerotic disease. Vessel wall imaging may be useful to define pathophysiology in patients with IC stenosis and could ultimately help tailor therapy, but further studies are needed. Medical therapy is preferred to stenting for patients with vertebral artery-origin stenosis.

Summary

Recent data and emerging concepts regarding large vessel atherosclerosis are provided.

Randomized Trial of Stent versus Surgery for Asymptomatic Carotid Stenosis

BACKGROUND

Previous clinical trials have suggested that carotid-artery stenting with a device to capture and remove emboli ("embolic protection") is an effective alternative to carotid endarterectomy in patients at average or high risk for surgical complications.

METHODS

In this trial, we compared carotid-artery stenting with embolic protection and carotid endarterectomy in patients 79 years of age or younger who had severe carotid stenosis and were asymptomatic (i.e., had not had a stroke, transient ischemic attack, or amaurosis fugax in the 180 days before enrollment) and were not considered to be at high risk for surgical complications. The trial was designed to enroll 1658 patients but was halted early, after 1453 patients underwent randomization, because of slow enrollment. Patients were followed for up to 5 years. The primary composite end point of death, stroke, or myocardial infarction within 30 days after the procedure or ipsilateral stroke within 1 year was tested at a noninferiority margin of 3 percentage points.

RESULTS

Stenting was noninferior to endarterectomy with regard to the primary composite end point (event rate, 3.8% and 3.4%, respectively; P=0.01 for noninferiority). The rate of stroke or death within 30 days was 2.9% in the stenting group and 1.7% in the endarterectomy group (P=0.33). From 30 days to 5 years after the procedure, the rate of freedom from ipsilateral stroke was 97.8% in the stenting group and 97.3% in the endarterectomy group (P=0.51), and the overall survival rates were 87.1% and 89.4%, respectively (P=0.21). The cumulative 5-year rate of stroke-free survival was 93.1% in the stenting group and 94.7% in the endarterectomy group (P=0.44).

CONCLUSIONS

In this trial involving asymptomatic patients with severe carotid stenosis who were not at high risk for surgical complications, stenting was noninferior to endarterectomy with regard to the rate of the primary composite end point at 1 year. In analyses that included up to 5 years of follow-up, there were no significant differences between the study groups in the rates of non-procedure-related stroke, all stroke, and survival. (Funded by Abbott Vascular; ACT I ClinicalTrials.gov number, NCT00106938.).

Modulation of stroke risk in chronic kidney disease

Stroke is the second most common cause of death and the leading cause of neurological disability worldwide, with huge economic costs and tragic human consequences. Both chronic kidney disease (CKD) and end-stage kidney disease are associated with a significantly increased risk of stroke. However, to date this has generated far less interest compared with the better-recognized links between cardiac and renal disease. Common risk factors for stroke, such as hypertension, hypercholesterolaemia, smoking and atrial fibrillation, are shared with the general population but are more prevalent in renal patients. In addition, factors unique to these patients, such as disorders of mineral and bone metabolism, anaemia and its treatments as well as the process of dialysis itself, are all also postulated to further increase the risk of stroke. In the general population, advances in medical therapies mean that effective primary and secondary prevention therapies are available for many patients. The development of specialist stroke clinics and acute stroke units has also improved outcomes after a stroke. Emerging therapies such as thrombolysis and thrombectomy are showing increasingly beneficial results. However, patients with CKD and on dialysis have different risk profiles that must be taken into account when considering the potential benefits and risks of these treatments. Unfortunately, these patients are either not recruited or formally excluded from major clinical trials. There is still much work to be done to harness effective stroke treatments with an acceptable safety profile for patients with CKD and those on dialysis.

Plaque Echolucency and the Risk of Ischaemic Stroke in Patients with Asymptomatic Carotid Stenosis Within the First Asymptomatic Carotid Surgery Trial (ACST-1)

OBJECTIVE/BACKGROUND

On ultrasound, potentially "high risk" carotid plaques may appear echolucent. In this study, whether a confident classification of echolucent plaque was a predictor of future ipsilateral ischaemic stroke in asymptomatic patients randomized to medical therapy in the Asymptomatic Carotid Surgery Trial-1 (ACST-1) was assessed.

METHODS

We performed a post-hoc analysis of 814 ACST-1 patients randomized to medical therapy alone with baseline plaque assessment classified as definitely echolucent (> 25% soft plaque) or nonecholucent (< 25% soft plaque). Kaplan-Meier survival curves were used to compare cumulative rates of ipsilateral ischaemic stroke in both groups.

RESULTS

In the first 5 years after randomization, a significantly higher risk of ipsilateral stroke was observed in patients with definitely echolucent plaques (8.0%; 95% confidence interval [CI] 6.4-9.6) when compared with patients with definitely nonecholucent plaques (3.1%; 95% CI 2.1-4.1; p = .009). After adjustments for other risk factors, plaque echolucency was associated with a 2.5-times increased risk of ipsilateral ischaemic stroke (hazard ratio 2.52; 95% CI 1.20-5.25; p = .014). Use of lipid-lowering therapy was low in both groups during the first 5 years after randomization but rose sharply during years 5-10 of follow-up, and was significantly more likely to be prescribed for patients with echolucent plaques (p = .001). The risk of ipsilateral ischaemic stroke at 10 years was similar for both groups of patients (p = .233).

CONCLUSION

Although the numbers of events in this study was low, definite plaque echolucency (> 25% soft plaque) was associated with a higher 5-year ipsilateral stroke risk in ACST-1 and may therefore help to identify patients at increased risk of stroke for whom carotid intervention may be particularly beneficial.

Systematic Review of Guidelines for the Management of Asymptomatic and Symptomatic Carotid Stenosis

BACKGROUND AND PURPOSE

We systematically compared and appraised contemporary guidelines on management of asymptomatic and symptomatic carotid artery stenosis.

METHODS

We systematically searched for guideline recommendations on carotid endarterectomy (CEA) or carotid angioplasty/stenting (CAS) published in any language between January 1, 2008, and January 28, 2015. Only the latest guideline per writing group was selected. Each guideline was analyzed independently by 2 to 6 authors to determine clinical scenarios covered, recommendations given, and scientific evidence used.

RESULTS

Thirty-four eligible guidelines were identified from 23 different regions/countries in 6 languages. Of 28 guidelines with asymptomatic carotid artery stenosis procedural recommendations, 24 (86%) endorsed CEA (recommended it should or may be provided) for ≈50% to 99% average-surgical-risk asymptomatic carotid artery stenosis, 17 (61%) endorsed CAS, 8 (29%) opposed CAS, and 1 (4%) endorsed medical treatment alone. For asymptomatic carotid artery stenosis patients considered high-CEA-risk because of comorbidities, vascular anatomy, or undefined reasons, CAS was endorsed in 13 guidelines (46%). Thirty-one of 33 guidelines (94%) with symptomatic carotid artery stenosis procedural recommendations endorsed CEA for patients with ≈50% to 99% average-CEA-risk symptomatic carotid artery stenosis, 19 (58%) endorsed CAS and 9 (27%) opposed CAS. For high-CEA-risk symptomatic carotid artery stenosis because of comorbidities, vascular anatomy, or undefined reasons, CAS was endorsed in 27 guidelines (82%). Guideline procedural recommendations were based only on results of trials in which patients were randomized 12 to 34 years ago, rarely reflected medical treatment improvements and often understated potential CAS hazards. Qualifying terminology summarizing recommendations or evidence lacked standardization, impeding guideline interpretation, and comparison.

CONCLUSIONS

This systematic review has identified many opportunities to modernize and otherwise improve carotid stenosis management guidelines.

[Treatment reality of internal carotid artery stenosis in Germany : requirement and reality in international comparison and in light of the current S3 guidelines]

BACKGROUND

Severe atherosclerotic extracranial carotid artery stenosis accounts for 5-10 % of all ischemic strokes. Currently, therapeutic recommendations are undergoing changes, particularly regarding the treatment of asymptomatic stenosis. Consolidated knowledge on the indications, nationwide distribution and numbers of cases are not available. Moreover, the impact and grade of implementation of the recently published national S3 guidelines on the reality of medical treatment remain unclear.

METHODS

Analysis of administrative hospital data involving the diagnosis-related groups (DRG) statistics and structured quality reports for 2010 and 2013 to evaluate the procedural therapy trends concerning operative and interventional approaches for symptomatic and asymptomatic carotid artery stenoses.

RESULTS

In Germany approximately 37,000 carotid endarterectomies (CEA) and approximately 5,000 carotid angioplasties with stenting (CAS) are carried out per year. Approximately 94 % of CEA and 62 % of CAS are performed in centers with more than 25 procedures per year. Only 33 % of CEA and 39 % of CAS are related to symptomatic stenosis.

CONCLUSION

Mathematically, an undertreatment of symptomatic and an overtreatment of asymptomatic carotid artery stenoses become apparent. Efforts should be made to achieve inpatient medical treatment conforming to the national S3 guidelines, in particular to adequately reduce the risk of stroke recurrence in patients with atherosclerotic symptomatic carotid artery stenosis.

Carotid Disease Management: Surgery, Stenting, or Medication

Internal carotid artery stenosis accounts for about 7-10 % of ischemic strokes. Conventional risk factors such as aging, hypertension, diabetes mellitus, and smoking increase the risk for carotid atherosclerosis. All patients with carotid stenosis should receive aggressive medical therapy. Carotid revascularization with either endarterectomy or stenting can benefit select patients with severe stenosis. New clinical trials will examine the contemporary role of carotid revascularization relative to optimal medical therapy.

Temporal trends in safety of carotid endarterectomy in asymptomatic patients: systematic review

OBJECTIVE

To systematically review temporal changes in perioperative safety of carotid endarterectomy (CEA) in asymptomatic individuals in trial and registry studies.

METHODS

The MEDLINE and EMBASE databases were searched using the terms "carotid" and "endarterectomy" and "asymptomatic" from 1947 to August 23, 2014. Articles dealing with 50%-99% stenosis in asymptomatic individuals were included and low-volume studies were excluded. The primary endpoint was 30-day stroke or death and the secondary endpoint was 30-day all-cause mortality. Statistical analysis was performed using random-effects meta-regression for registry data and for trial data graphical interpretation alone was used.

RESULTS

Six trials (n = 4,431 procedures) and 47 community registries (n = 204,622 procedures) reported data between 1983 and 2013. Registry data showed a significant decrease in postoperative stroke or death incidence over the period 1991-2010, equivalent to a 6% average proportional annual reduction (95% credible interval [CrI] 4%-7%; p < 0.001). Considering postoperative all-cause mortality, registry data showed a significant 5% average proportional annual reduction (95% CrI 3%-9%; p < 0.001). Trial data showed a similar visual trend.

CONCLUSIONS

CEA is safer than ever before and high-volume registry results closely mirror the results of trials. New benchmarks for CEA are a stroke or death risk of 1.2% and a mortality risk of 0.4%. This information will prove useful for quality improvement programs, for health care funders, and for those re-examining the long-term benefits of asymptomatic revascularization in future trials.

Risk of Stroke and Cardiac Events in Medically Treated Asymptomatic Carotid Stenosis

BACKGROUND

The risk of stroke in patients with 50% or more asymptomatic carotid stenosis (ACS) on intensive medical treatment is low. Hence, the optimal treatment of ACS remains controversial at this point of time.

AIM

We assessed the risk of stroke/transient ischemic attack (TIA) and cardiac events in patients with 50% or more ACS on intensive medical treatment.

METHODS

All patients with TIA/minor stroke (National Institutes of Health Stroke Scale score ≤5) who had undergone vessel imaging as part of their evaluation and patients with coronary artery disease who had undergone vessel imaging before cardiac intervention were screened for the presence of asymptomatic carotid stenosis. The risk of TIA/stroke, cardiac events, and vascular deaths were evaluated.

RESULTS

Of 1,800 patients, 92 patients (.05%) had ACS having 50% to 99% stenosis; 63 had TIA/minor stroke, and 29 had coronary artery disease, of whom 7 patients had bilateral ACS, thus constituting 99 study units of ACS. The mean follow-up was 34.7 months (range 3-120 months). Two patients developed ischemic events on the side ipsilateral to the ACS and 9 patients developed cardiac events during the follow-up. The average annual event rate for cerebral ischemic events was .93% (95% confidence interval [CI], .11-3.37), 4.21% (95% CI, 1.92-7.98) for cardiac events, and 3.27% (95% CI, 1.31-6.74) for death.

CONCLUSIONS

Although the risk of stroke in patients with ACS is low, acute coronary events and vascular deaths were significant. This highlights the importance of intensive risk factor modification to reduce adverse cardiovascular events in ACS rather than revascularization of the carotid stenosis.

Medical and Revascularization Therapies for Asymptomatic Carotid Stenosis

Asymptomatic internal carotid artery stenosis increases with age and is more common in men. Carotid endarterectomy and stenting have reduced stroke rates in patients with asymptomatic carotid stenosis in clinical trials. A variety of risk stratification methods are available for selection of patients with carotid stenosis for revascularization. In the past decade, there is increasing evidence that the rate of stroke declined with the use of aggressive multi-modal medical therapy. These developments have led to new clinical trials to compare revascularization versus aggressive medical therapy in patients with asymptomatic carotid stenosis.

Markers of inflammation associated with plaque progression and instability in patients with carotid atherosclerosis

Atherosclerosis is the focal expression of a systemic disease affecting medium- and large-sized arteries, in which traditional cardiovascular risk factor and immune factors play a key role. It is well accepted that circulating biomarkers, including C-reactive protein and interleukin-6, reliably predict major cardiovascular events, including myocardial infarction or death. However, the relevance of biomarkers of systemic inflammation to atherosclerosis progression in the carotid artery is less established. The large majority of clinical studies focused on the association between biomarkers and subclinical atherosclerosis, that is, carotid intima-media thickening (cIMT), which represents an earlier stage of the disease. The aim of this work is to review inflammatory biomarkers that were associated with a higher atherosclerotic burden, a faster disease progression, and features of plaque instability, such as inflammation or neovascularization, in patients with carotid atherosclerotic plaque, which represents an advanced stage of disease compared with cIMT. The association of biomarkers with the occurrence of cerebrovascular events, secondary to carotid plaque rupture, will also be presented. Currently, the degree of carotid artery stenosis is used to predict the risk of future cerebrovascular events in patients affected by carotid atherosclerosis. However, this strategy appears suboptimal. The identification of suitable biomarkers could provide a useful adjunctive criterion to ensure better risk stratification and optimize management.

Comparative outcomes of carotid artery stenting for asymptomatic and symptomatic carotid artery stenosis: a single-center prospective study

Background

Carotid artery stenting (CAS) for symptomatic carotid artery stenosis (SCS) has been proved to be safe and effective in many randomized controlled trials, but the safety and efficacy of CAS for asymptomatic carotid artery stenosis (ACS) is not clear.

Objective

To prospectively compare the outcomes of CAS between patients with ACS and SCS.

Methods

402 consecutive patients, 233 with ACS and 169 with SCS, underwent CAS. The primary outcome was a composite of death, stroke or myocardial infarction at 30 days and during the follow-up period. Procedural success and complications such as hyperperfusion, sinus-cardiac reflex, gastrointestinal hemorrhage, myocardial infarction, acute thrombosis, and vagus nerve reflex were also compared between the ACS and SCS groups.

Results

CAS was successful in all patients. There were no significant differences in baseline characteristics of the patients (age, gender, hypertension, diabetes, smoking, alcohol consumption and dyslipidemia) and in 30-day or long-term follow-up outcomes between the ACS and SCS groups.

Conclusions

Periprocedural and long-term follow-up outcomes of CAS appear similar for ACS and SCS.

Prediction of asymptomatic carotid artery stenosis in the general population: identification of high-risk groups

BACKGROUND AND PURPOSE

Because of a low prevalence of severe carotid stenosis in the general population, screening for presence of asymptomatic carotid artery stenosis (ACAS) is not warranted. Possibly, for certain subgroups, screening is worthwhile. The present study aims to develop prediction rules for the presence of ACAS (>50% and >70%).

METHODS

Individual participant data from 4 population-based cohort studies (Malmö Diet and Cancer Study, Tromsø Study, Carotid Atherosclerosis Progression Study, and Cardiovascular Health Study; totaling 23 706 participants) were pooled. Multivariable logistic regression was performed to determine which variables predict presence of ACAS (>50% and >70%). Calibration and discrimination of the models were assessed, and bootstrapping was used to correct for overfitting.

RESULTS

Age, sex, history of vascular disease, systolic and diastolic blood pressure, total cholesterol/high-density lipoprotein ratio, diabetes mellitus, and current smoking were predictors of stenosis (>50% and >70%). The calibration of the model was good confirmed by a nonsignificant Hosmer and Lemeshow test for moderate (P=0.59) and severe stenosis (P=0.07). The models discriminated well between participants with and without stenosis, with an area under the receiver operating characteristic curve corrected for over optimism of 0.82 (95% confidence interval, 0.80-0.84) for moderate stenosis and of 0.87 (95% confidence interval, 0.85-0.90) for severe stenosis. The regression coefficients of the predictors were converted into a score chart to facilitate practical application.

CONCLUSIONS

A clinical prediction rule was developed that allows identification of subgroups with high prevalence of moderate (>50%) and severe (>70%) ACAS. When confirmed in comparable cohorts, application of the prediction rule may lead to a reduction in the number needed to screen for ACAS.