Asymptomatic carotid artery stenosis--medical therapy alone versus medical therapy plus carotid endarterectomy or stenting

Seven years of the transcarotid artery revascularization surveillance project, comparison to transfemoral stenting and endarterectomy

OBJECTIVE

This study utilizes the latest data from the Vascular Quality Initiative (VQI), which now encompasses over 50,000 transcarotid artery revascularization (TCAR) procedures, to offer a sizeable dataset for comparing the effectiveness and safety of TCAR, transfemoral carotid artery stenting (tfCAS), and carotid endarterectomy (CEA). Given this substantial dataset, we are now able to compare outcomes overall and stratified by symptom status across revascularization techniques.

METHODS

Utilizing VQI data from September 2016 to August 2023, we conducted a risk-adjusted analysis by applying inverse probability of treatment weighting to compare in-hospital outcomes between TCAR vs tfCAS, CEA vs tfCAS, and TCAR vs CEA. Our primary outcome measure was in-hospital stroke/death. Secondary outcomes included myocardial infarction and cranial nerve injury.

RESULTS

A total of 50,068 patients underwent TCAR, 25,361 patients underwent tfCAS, and 122,737 patients underwent CEA. TCAR patients were older, more likely to have coronary artery disease, chronic kidney disease, and undergo coronary artery bypass grafting/percutaneous coronary intervention as well as prior contralateral CEA/CAS compared with both CEA and tfCAS. TfCAS had higher odds of stroke/death when compared with TCAR (2.9% vs 1.6%; adjusted odds ratio [aOR], 1.84; 95% confidence interval [CI], 1.65-2.06; P < .001) and CEA (2.9% vs 1.3%; aOR, 2.21; 95% CI, 2.01-2.43; P < .001). CEA had slightly lower odds of stroke/death compared with TCAR (1.3% vs 1.6%; aOR, 0.83; 95% CI, 0.76-0.91; P < .001). TfCAS had lower odds of cranial nerve injury compared with TCAR (0.0% vs 0.3%; aOR, 0.00; 95% CI, 0.00-0.00; P < .001) and CEA (0.0% vs 2.3%; aOR, 0.00; 95% CI, 0.0-0.0; P < .001) as well as lower odds of myocardial infarction compared with CEA (0.4% vs 0.6%; aOR, 0.67; 95% CI, 0.54-0.84; P < .001). CEA compared with TCAR had higher odds of myocardial infarction (0.6% vs 0.5%; aOR, 1.31; 95% CI, 1.13-1.54; P < .001) and cranial nerve injury (2.3% vs 0.3%; aOR, 9.42; 95% CI, 7.78-11.4; P < .001).

CONCLUSIONS

Although tfCAS may be beneficial for select patients, the lower stroke/death rates associated with CEA and TCAR are preferred. When deciding between CEA and TCAR, it is important to weigh additional procedural factors and outcomes such as myocardial infarction and cranial nerve injury, particularly when stroke/death rates are similar. Additionally, evaluating subgroups that may benefit from one procedure over another is essential for informed decision-making and enhanced patient care in the treatment of carotid stenosis.

A deep learning-based calculation system for plaque stenosis severity on common carotid artery of ultrasound images

OBJECTIVES

Assessment of plaque stenosis severity allows better management of carotid source of stroke. Our objective is to create a deep learning (DL) model to segment carotid intima-media thickness and plaque and further automatically calculate plaque stenosis severity on common carotid artery (CCA) transverse section ultrasound images.

METHODS

Three hundred and ninety images from 376 individuals were used to train (235/390, 60%), validate (39/390, 10%), and test (116/390, 30%) on a newly proposed CANet model. We also evaluated the model on an external test set of 115 individuals with 122 images acquired from another hospital. Comparative studies were conducted between our CANet model with four state-of-the-art DL models and two experienced sonographers to re-evaluate the present model's performance.

RESULTS

On the internal test set, our CANet model outperformed the four comparative models with Dice values of 95.22% versus 90.15%, 87.48%, 90.22%, and 91.56% on lumen-intima (LI) borders and 96.27% versus 91.40%, 88.94%, 91.19%, and 92.88% on media-adventitia (MA) borders. On the external test set, our model still produced excellent results with a Dice value of 92.41%. Good consistency of stenosis severity calculation was observed between CANet model and experienced sonographers, with Intraclass Correlation Coefficient (ICC) of 0.927 and 0.702, Pearson's Correlation Coefficient of 0.928 and 0.704 on internal and external test set, respectively.

CONCLUSIONS

Our CANet model achieved excellent performance in the segmentation of carotid IMT and plaques as well as automated calculation of stenosis severity.

Establishing a carotid artery stenosis disease cohort for comparative effectiveness research using natural language processing

OBJECTIVE

Investigation of asymptomatic carotid stenosis treatment is hindered by the lack of a contemporary population-based disease cohort. We describe the use of natural language processing (NLP) to identify stenosis in patients undergoing carotid imaging.

METHODS

Adult patients with carotid imaging between 2008 and 2012 in a large integrated health care system were identified and followed through 2017. An NLP process was developed to characterize carotid stenosis according to the Society of Radiologists in Ultrasound (for ultrasounds) and North American Symptomatic Carotid Endarterectomy Trial (NASCET) (for axial imaging) guidelines. The resulting algorithm assessed text descriptors to categorize normal/non-hemodynamically significant stenosis, moderate or severe stenosis as well as occlusion in both carotid ultrasound (US) and axial imaging (computed tomography and magnetic resonance angiography [CTA/MRA]). For US reports, internal carotid artery systolic and diastolic velocities and velocity ratios were assessed and matched for laterality to supplement accuracy. To validate the NLP algorithm, positive predictive value (PPV or precision) and sensitivity (recall) were calculated from simple random samples from the population of all imaging studies. Lastly, all non-normal studies were manually reviewed for confirmation for prevalence estimates and disease cohort assembly.

RESULTS

A total of 95,896 qualifying index studies (76,276 US and 19,620 CTA/MRA) were identified among 94,822 patients including 1059 patients who underwent multiple studies on the same day. For studies of normal/non-hemodynamically significant stenosis arteries, the NLP algorithm showed excellent performance with a PPV of 99% for US and 96.5% for CTA/MRA. PPV/sensitivity to identify a non-normal artery with correct laterality in the CTA/MRA and US samples were 76.9% (95% confidence interval [CI], 74.1%-79.5%)/93.1% (95% CI, 91.1%-94.8%) and 74.7% (95% CI, 69.3%-79.5%)/94% (95% CI, 90.2%-96.7%), respectively. Regarding cohort assembly, 15,522 patients were identified with diseased carotid artery, including 2674 exhibiting equal bilateral disease. This resulted in a laterality-specific cohort with 12,828 moderate, 5283 severe, and 1895 occluded arteries and 326 diseased arteries with unknown stenosis. During follow-up, 30.1% of these patients underwent 61,107 additional studies.

CONCLUSIONS

Use of NLP to detect carotid stenosis or occlusion can result in accurate exclusion of normal/non-hemodynamically significant stenosis disease states with more moderate precision with lesion identification, which can substantially reduce the need for manual review. The resulting cohort allows for efficient research and holds promise for similar reporting in other vascular diseases.

Long-term stroke risk with carotid endarterectomy in patients with severe carotid stenosis

OBJECTIVE

Informed debate regarding the optimal use of carotid endarterectomy (CEA) for stroke risk reduction requires contemporary assessment of both long-term risk and periprocedural risk. In this study, we report long-term stroke and death risk after CEA in a large integrated health care system.

METHODS

All patients with documented severe (70%-99%) stenosis from 2008 to 2012 who underwent CEA were identified and stratified by asymptomatic or symptomatic indication. Those with prior ipsilateral interventions were excluded. Patients were followed up through 2017 for the primary outcomes of any stroke/death within 30 days of intervention and long-term ipsilateral ischemic stroke; secondary outcomes were any stroke and overall survival.

RESULTS

Overall, 1949 patients (63.2% male; mean age, 71.3 ± 8.9 years) underwent 2078 primary CEAs, 1196 (58%) for asymptomatic stenosis and 882 (42%) for symptomatic stenosis. Mean follow-up was 5.5 ± 2.7 years. Median time to surgery was 72.0 (interquartile range, 38.5-198.0) days for asymptomatic patients and 21.0 (interquartile range, 5.0-55.0) days for symptomatic patients (P < .001). Most of the patients' demographics and characteristics were similar in both groups. Controlled blood pressure rates were similar at the time of CEA. Baseline statin use was seen in 60.5% of the asymptomatic group compared with 39.9% in the symptomatic group (P < .001), and statin adherence by 80% medication possession ratio was 19.3% asymptomatic vs 12.4% symptomatic (P < .001). The crude overall 30-day any stroke/death rates were 0.9% and 1.5% for the asymptomatic group and the symptomatic group, respectively. The 5-year risk of ipsilateral stroke and a combined end point of any stroke/death by Kaplan-Meier survival analysis were 2.5% and 28.7% for the asymptomatic group and 4.0% and 31.4% for the symptomatic group, respectively. Unadjusted cumulative all-cause survival was 74.2% for the asymptomatic group and 71.8% for the symptomatic group at 5 years.

CONCLUSIONS

In a contemporary review of CEA, outcomes for either operative indication show low adverse events perioperatively and low long-term stroke risk up to 5 years. These results are well within consensus guidelines and published trial outcomes and should help inform the discussion around optimal CEA use for severe carotid stenosis.

Clinical impact of sex on carotid revascularization

BACKGROUND

The impact of sex in the management of carotid disease is unclear in the current literature. Therefore, we evaluated the effect of sex on perioperative outcomes following carotid endarterectomy (CEA) and carotid artery stenting (CAS).

METHODS

We included patients who underwent CEA or CAS between 2012 and 2017 in the Vascular Quality Initiative database. Our primary outcome was perioperative stroke/death. Secondary outcomes were in-hospital stroke, 30-day mortality, and in-hospital MI. We compared perioperative outcomes between female and male patients, stratified by treatment modality and symptom status, and used multivariable regression to account for differences in baseline characteristics.

RESULTS

A total of 83,436 patients underwent either a CEA (71,383) or CAS (12,053). Asymptomatic and symptomatic CEA females were less likely to be on a preoperative antiplatelet agent, when compared to males. Females overall, were less likely to be on a preoperative statin and more likely to have chronic obstructive pulmonary disease. Within the CAS cohort, females were more likely to have a previous ipsilateral CEA. There were no differences between males and females in major adverse events following CEA for asymptomatic disease. Following CEA for symptomatic disease, there was no difference in stroke/death rate or in-hospital stroke. However, females experienced a higher 30-mortality after adjustment (univariate: 1.0% vs 0.7%, P = .04; adjusted: odds ratio [OR], 1.4:1.02-1.94). Following CAS for asymptomatic disease, females experienced a higher rate of perioperative stroke/death (2.9% vs 1.9% P = .02; OR, 1.5: 1.05-2.03) and in-hospital stroke (2.1% vs 1.2% P = .01; OR, 1.8: 1.20-2.60). There were no differences in outcomes for symptomatic females vs males undergoing CAS.

CONCLUSIONS

Females with carotid disease less frequently receive optimal medical treatment with antiplatelet agents and statins. This is an important target area for quality improvement issue in both females and males. Furthermore, among symptomatic CEA patients the female sex is associated with higher mortality and among asymptomatic CAS patients, females experience higher rates of stroke/death. These findings suggest that careful patient selection is necessary in the treatment of female patients. Quality improvement projects should be created to further investigate and eliminate the disparities of optimal medical management between the sexes.

Ultrasound-based carotid stenosis measurement and risk stratification in diabetic cohort: a deep learning paradigm

BACKGROUND

Stroke is in the top three leading causes of death worldwide. Non-invasive monitoring of stroke can be accomplished via stenosis measurements. The current conventional image-based methods for these measurements are not accurate and reliable. They do not incorporate shape and intelligent learning component in their design.

METHODS

In this study, we propose a deep learning (DL)-based methodology for accurate measurement of stenosis in common carotid artery (CCA) ultrasound (US) scans using a class of AtheroEdge system from AtheroPoint, USA. Three radiologists manually traced the lumen-intima (LI) for the near and the far walls, respectively, which served as a gold standard (GS) for training the DL-based model. Three DL-based systems were developed based on three types of GS.

RESULTS

IRB approved (Toho University, Japan) 407 US scans from 204 patients were collected. The risk was characterized into three classes: low, moderate, and high-risk. The area-under-curve (AUC) corresponding to three DL systems using receiver operating characteristic (ROC) analysis computed were: 0.90, 0.94 and 0.86, respectively.

CONCLUSIONS

Novel DL-based strategy showed reliable, accurate and stable stenosis severity index (SSI) measurements.

Angioplasty in asymptomatic carotid artery stenosis vs. endarterectomy compared to best medical treatment: One-year interim results of SPACE-2

BACKGROUND

Treatment of individuals with asymptomatic carotid artery stenosis is still handled controversially. Recommendations for treatment of asymptomatic carotid stenosis with carotid endarterectomy (CEA) are based on trials having recruited patients more than 15 years ago. Registry data indicate that advances in best medical treatment (BMT) may lead to a markedly decreasing risk of stroke in asymptomatic carotid stenosis. The aim of the SPACE-2 trial (ISRCTN78592017) was to compare the stroke preventive effects of BMT alone with that of BMT in combination with CEA or carotid artery stenting (CAS), respectively, in patients with asymptomatic carotid artery stenosis of ≥70% European Carotid Surgery Trial (ECST) criteria.

METHODS

SPACE-2 is a randomized, controlled, multicenter, open study. A major secondary endpoint was the cumulative rate of any stroke (ischemic or hemorrhagic) or death from any cause within 30 days plus an ipsilateral ischemic stroke within one year of follow-up. Safety was assessed as the rate of any stroke and death from any cause within 30 days after CEA or CAS. Protocol changes had to be implemented. The results on the one-year period after treatment are reported.

FINDINGS

It was planned to enroll 3550 patients. Due to low recruitment, the enrollment of patients was stopped prematurely after randomization of 513 patients in 36 centers to CEA (n = 203), CAS (n = 197), or BMT (n = 113). The one-year rate of the major secondary endpoint did not significantly differ between groups (CEA 2.5%, CAS 3.0%, BMT 0.9%; p = 0.530) as well as rates of any stroke (CEA 3.9%, CAS 4.1%, BMT 0.9%; p = 0.256) and all-cause mortality (CEA 2.5%, CAS 1.0%, BMT 3.5%; p = 0.304). About half of all strokes occurred in the peri-interventional period. Higher albeit statistically non-significant rates of restenosis occurred in the stenting group (CEA 2.0% vs. CAS 5.6%; p = 0.068) without evidence of increased stroke rates.

INTERPRETATION

The low sample size of this prematurely stopped trial of 513 patients implies that its power is not sufficient to show that CEA or CAS is superior to a modern medical therapy (BMT) in the primary prevention of ischemic stroke in patients with an asymptomatic carotid stenosis up to one year after treatment. Also, no evidence for differences in safety between CAS and CEA during the first year after treatment could be derived. Follow-up will be performed up to five years. Data may be used for pooled analysis with ongoing trials.

Improvement of Pituitary Function after Carotid Revascularization in Patients with Abnormal Cerebral Perfusion - A Pilot Study

Background

Brain ischemia may affect hypothalamic-pituitary axis function, which may influence the outcomes of patients with internal carotid artery (ICA) stenosis/occlusion. The objective of this study was to determine the influence of successful carotid revascularization on pituitary function in patients with severe ICA stenosis/occlusion.

Methods

This study was conducted from April 2009 to December 2014. Patients receiving successful endovascular interventions for severe ICA stenosis/occlusion were enrolled. The patients were divided into 2 groups: group 1 with abnormal ipsilateral cerebral perfusion, and group 2 without. Endocrine profiles were measured before and > 1 year after the procedure. Computed tomography perfusion studies were used to assess brain perfusion.

Results

Thirty-seven patients received successful interventions. Three patients were excluded due to re-stenosis before 1 year. There were 23 and 11 patients in group 1 and 2, with mean ages of 68 and 69 years, respectively. In the female patients, follicular stimulating hormone (FSH) and luteinizing hormone (LH) increased significantly (p = 0.043) after the interventions with a stable estradiol level in group 1. In contrast, FSH, LH and estradiol showed a decreasing trend in group 2. In the male patients, FSH and LH increased significantly (p < 0.01) after the interventions with a stable testosterone level in group 1, while testosterone showed a decreasing trend in group 2. Thyroid stimulating hormone increased significantly in the women in both groups, and in the men in group 1.

Conclusions

Successful revascularization for severe ICA stenosis/occlusion may improve their pituitary function, especially FSH and LH levels.

Carotid endarterectomy should not be based on consensus statement duplex velocity criteria

OBJECTIVE

Randomized trials support carotid endarterectomy (CEA) in asymptomatic patients with ≥60% internal carotid artery (ICA) stenosis. The widely referenced Society for Radiologists in Ultrasound Consensus Statement on carotid duplex ultrasound (CDUS) imaging indicates that an ICA peak systolic velocity (PSV) ≥230 cm/s corresponds to a ≥70% ICA stenosis, leading to the potential conclusion that asymptomatic patients with an ICA PSV ≥230 cm/s would benefit from CEA. Our goal was to determine the natural history stroke risk of asymptomatic patients who might have undergone CEA based on consensus statement PSV of ≥230 cm/s but instead were treated medically based on more conservative CDUS imaging criteria.

METHODS

All patients who underwent CDUS imaging at our institution during 2009 were retrospectively reviewed. The year 2009 was chosen to ensure extended follow-up. Asymptomatic patients were included if their ICA PSV was ≥230 cm/s but less than what our laboratory considers a ≥80% stenosis by CDUS imaging (PSV ≥430 cm/s, end-diastolic velocity ≥151 cm/s, or ICA/common carotid artery PSV ratio ≥7.5). Study end points included freedom from transient ischemic attack (TIA), freedom from any stroke, freedom from carotid-etiology stroke, and freedom from revascularization.

RESULTS

Criteria for review were met by 327 patients. Mean follow-up was 4.3 years, with 85% of patients having >3-year follow-up. Four unheralded strokes occurred during follow-up at <1, 17, 25, and 30 months that were potentially attributable to the index carotid artery. Ipsilateral TIA occurred in 17 patients. An additional 12 strokes occurred that appeared unrelated to ipsilateral carotid disease, including hemorrhagic events, contralateral, and cerebellar strokes. Revascularization was undertaken in 59 patients, 1 for stroke, 12 for TIA, and 46 for asymptomatic disease. Actuarial freedom from carotid-etiology stroke was 99.7%, 98.4%, and 98.4% at 1, 3, and 5 years, respectively. Freedom from TIA was 98%, 96%, and 95%, freedom from any stroke was 99%, 96%, and 93%, and freedom from revascularization was 95%, 86%, and 81% at 1, 3, and 5 years, respectively.

CONCLUSIONS

Patients with intermediate asymptomatic carotid stenosis (ICA PSV 230-429 cm/s) do well with medical therapy when carefully monitored and intervened upon using conservative CDUS criteria. Furthermore, a substantial number of patients would undergo unnecessary CEA if consensus statement CDUS thresholds are used to recommend surgery. Current velocity threshold recommendations should be re-evaluated, with potentially important implications for upcoming clinical trials.

An update on predictive biomarkers for major adverse cardiovascular events in patients undergoing vascular surgery

Cardiovascular complications signify a major cause of morbidity and mortality in patients undergoing vascular surgery adversely affecting both short- and long-term prognosis. During the last decade, unmet needs for a distinct cardiovascular risk assessment have led to an intensive research for establishment of biomarkers with sufficient predictive value. This literature review aims in examining the value of several biomarkers in predicting the incidence of major adverse cardiac events in vascular surgery patients. We reviewed the English language literature and analyzed the biomarkers as independent predictors or in correlation with other factors. We found several biomarkers showing a significant predictive value for a major adverse cardiovascular event in patients undergoing vascular surgery. These biomarkers can be used in clinical practice as outcome predictors, although sensitivity and specificity varies. Detection of subclinical cardiovascular damage may improve total risk estimation and facilitate clinical assessment of patients at risk for future cardiovascular events. The wide variety of sensitivity and specificity in predicting a MACE of these biomarkers exert the need for future trials in which these markers will be tested as adjunctive tools of cardiovascular risk estimation scoring systems.

The value and economic analysis of routine postoperative carotid duplex ultrasound surveillance after carotid endarterectomy

BACKGROUND

Several studies have reported on the role of postoperative duplex ultrasound surveillance after carotid endarterectomy (CEA) with varying results. Most of these studies had a small sample size or did not analyze cost-effectiveness.

METHODS

We analyzed 489 of 501 CEA patients with patch closure. All patients had immediate postoperative duplex ultrasound examination and were routinely followed up both clinically and with duplex ultrasound at regular intervals of 1 month, 6 months, 12 months, and every 12 months thereafter. A Kaplan-Meier analysis was used to estimate the rate of ≥50% and ≥80% post-CEA restenosis over time and the time frame of progression from normal to ≥50% or ≥80% restenosis. The cost of post-CEA duplex surveillance was also estimated.

RESULTS

Overall, 489 patients with a mean age of 68.5 years were analyzed. Ten of these had residual postoperative ≥50% stenosis, and 37 did not undergo a second duplex ultrasound examination and therefore were not included in the final analysis. The mean follow-up was 20.4 months (range, 1-63 months), with a mean number of duplex ultrasound examinations of 3.6 (range, 1-7). Eleven of 397 patients (2.8%) with a normal finding on immediate postoperative duplex ultrasound vs 4 of 45 (8.9%) with mild stenosis on immediate postoperative duplex ultrasound progressed to ≥50% restenosis (P = .055). Overall, 15 patients (3.1%) had ≥50% restenosis, 9 with 50% to <80% and 4 with 80% to 99% (2 of these had carotid artery stenting reintervention), and 2 had late carotid occlusion. All of these were asymptomatic, except for one who had a transient ischemic attack. The mean time to ≥50% to <80% restenosis was 14.7 months vs 19.8 months for ≥80% restenosis after the CEA. Freedom from restenosis rates were 98%, 96%, 94%, 94%, and 94% for ≥50% restenosis and 99%, 98%, 97%, 97%, and 97% for ≥80% restenosis at 1 year, 2 years, 3 years, 4 years, and 5 years, respectively. Freedom from myocardial infarction, stroke, and deaths was not significantly different between patients with and without restenosis (100%, 93%, 83%, and 83% vs 94%, 91%, 86%, and 79% at 1 year, 2 years, 3 years, and 4 years, respectively; P = .951). The estimated charge of this surveillance was 3.6 × 489 (number of CEAs) × $800 (charge for carotid duplex ultrasound), which equals $1,408,320, to detect only four patients with ≥80% to 99% restenosis who may have been potential candidates for reintervention.

CONCLUSIONS

This study shows that the value of routine postoperative duplex ultrasound surveillance after CEA with patch closure may be limited, particularly if the finding on immediate postoperative duplex ultrasound is normal or shows minimal disease.

An Update on Italian Stroke Organization Guidelines on Carotid Endarterectomy and Stenting

One hundred and fifty-three authors, 45 Italian scientific societies, and two Italian patients' associations participated in drafting the Italian Stroke Organization document, which has become the national guideline for the prevention and treatment of stroke in Italy. For the surgical therapy section of the Italian Stroke Organization document, the main trials on carotid endoarterectomy and stenting were critically reviewed in order to formulate recommendations for these procedures. Recommendations are presented here for the referral of patients to either carotid endarterectomy or stenting on the basis of whether carotid stenosis is symptomatic or asymptomatic.

Neurocognitive functioning after carotid revascularization: a systematic review

BACKGROUND

The objective of this study was to review the recent literature regarding the neurocognitive consequences of carotid endarterectomy (CEA) and carotid stenting (CAS).

METHODS AND RESULTS

A PubMed and Web of Science search was conducted using the key words 'carotid' in combination with 'cognitive', 'cognition', 'neurocognition', 'neurocognitive', 'neuropsychology', and 'neuropsychological'. Bibliographies of relevant articles were cross-referenced. We included 37 studies published since 2007 of which 18 examined CEA, 12 CAS, and 7 compared CEA to CAS. There is a wide variability in the reported neurocognitive outcome following CEA and CAS. Nonetheless, none of the included studies unveiled significant differences between CEA and CAS on postoperative neurocognitive functioning. Postoperative changes observed for CEA and CAS separately seem limited to a small percentage (around 10-15%) of patients and can either present as an improvement or impairment.

KEY MESSAGES

The available data seem to suggest that no obvious cognitive differences between CAS and CEA can be observed after intervention. Both improvement and deterioration in cognitive functioning can be observed following CAS or CEA. Methodological differences such as patient heterogeneity, implementation and type of control groups, type of psychometric tests used, statistical analyses, or timing of the assessments play an important role in explaining the sometimes divergent results of the included studies. Large-scale and methodologically solid studies comparing CEA and CAS on neurocognitive outcome remain warranted. Future studies should implement adequate control groups to correct for practice effects in the target groups.

Asymptomatic carotid stenosis: immediate revascularization or watchful waiting?

Based on several randomized clinical trials, carotid revascularization has been shown to reduce future stroke risk among individuals with severe asymptomatic carotid stenosis. However, a well-recognized problem with such prophylactic intervention is the risk of periprocedural stroke, death, or myocardial infarction. If actual stroke risk with asymptomatic carotid stenosis can be reduced significantly by aggressive medical management, carotid revascularization may yield marginal benefit or even cause harm especially in those with limited life expectancy. Based on recent observational data, it is becoming apparent that the stroke risk in this population has been declining with better medical management alone. This has prompted a few to avoid carotid revascularization for asymptomatic carotid stenosis altogether. Others feel such conclusions cannot be made with observational data alone. In the midst of this controversy, it is important that clinicians perform carotid revascularization on a case by case basis while ensuring optimal medical management in all patients. An algorithmic approach to decision making based on available evidence will enable clinicians to personalize patient management with efficiency.

Application of Porter’s Five Forces Model and generic strategies for vascular surgery: should be stuck in the middle?

There are many stakeholders in the vascular marketplace from clinicians to hospitals, third party payers, medical device manufacturers and the government. Economic stress, threats of policy reform and changing health-care delivery are adding to the challenges faced by vascular surgeons. Use of Porter's Five Forces analysis to identify the sources of competition, the strength and likelihood of that competition existing, and barriers to competition that affect vascular surgery will help our specialty understand both the strength of our current competition and the strength of a position that our specialty will need to move to. By understanding the nature of the Porter's Five Forces as it applies to vascular surgery, and by appreciating their relative importance, our society would be in a stronger position to defend itself against threats and perhaps influence the forces with a long-term strategy. Porter's generic strategies attempt to create effective links for business with customers and suppliers and create barriers to new entrants and substitute products. It brings an initial perspective that is convenient to adapt to vascular surgery in order to reveal opportunities.Vascular surgery is uniquely situated to pursue both a differentiation and high value leadership strategy.

Screening for carotid artery stenosis and renal artery stenosis in patients undergoing tunneled cuffed hemodialysis catheter placement

In this study, we noted the common risk factors with atherosclerosis and chronic renal disease. We, therefore, hypothesized that the placement of a dialysis catheter would be a useful marker in identifying populations at increased risk of vascular disease (carotid, renal, and aortic). To further explore this issue, we examined the results of duplex scanning of the carotid arteries and aortorenal arteries in patients undergoing dialysis catheter placement. Over 49 months, each of the 123 patients who underwent permanent tunneled dialysis catheter placement received a carotid duplex study. Twelve patients (9.8%) had ≥ 60% stenosis and 8 patients (6.5%) had 70% to 99% stenosis. Furthermore, 109 patients who underwent a aortorenal artery duplex study were also analyzed. The study population demonstrated a prevalence rate of 3.7% for abdominal aorta aneurysm (AAA) and 4.6% for renal artery stenosis (RAS). Based upon these data, we suggest performing routine carotid duplex scans in patients who will also receive dialysis catheter placement. However, the data did not support routine screening of AAA or RAS.

Recommendations for management of patients with carotid stenosis

Stroke is a one of the leading causes of morbidity and mortality in the world. Carotid atherosclerosis is recognized as an important factor in stroke pathophysiology and represents a key target in stroke prevention; multiple treatment modalities have been developed to battle this disease. Multiple randomized trials have shown the efficacy of carotid endarterectomy in secondary stroke prevention. Carotid stenting, a newer treatment option, presents a less invasive alternative to the surgical intervention on carotid arteries. Advances in medical therapy have also enabled further risk reduction in the overall incidence of stroke. Despite numerous trials and decades of clinical research, the optimal management of symptomatic and asymptomatic carotid disease remains controversial. We will attempt to highlight some of the pivotal trials already completed, discuss the current controversies and complexities in the treatment decision-making, and postulate on what likely lies ahead. This paper will highlight the complexities of decision-making optimal treatment recommendations for patients with symptomatic and asymptomatic carotid stenosis.

Carotid stenting improves cognitive function in asymptomatic cerebral ischemia

OBJECTIVES

Asymptomatic critical internal carotid artery (ICA) stenosis may lead to cognitive impairment. Carotid stenting (CS) may improve cerebral perfusion, but its impact on neuro-cognitive function has been controversial.

METHODS

We prospectively enrolled 34 asymptomatic patients with unilateral ICA stenosis or occlusion, in whom CS was attempted. Computed tomography cerebral perfusion (CTP), and functional assessments including National Institutes of Health Stoke Scale (NIHSS), Bathel Index (BI), and a battery of neuropsychological tests including Mini-Mental State Examination (MMSE), Alzheimer Disease Assessment Scale-Cognitive Subtest (ADAS-Cog), verbal fluency, and Color Trail Making A and B, were done prior to and 3 months after the procedure.

RESULTS

Successful CS was achieved in 28 of 34 patients (82%). Based on the baseline CTP finding and intervention result, patients were divided into three groups: group I (n=6) as ipsilateral cerebral ischemia with failed CS procedure, group II (n=17) as ipsilateral cerebral ischemia with successful CS procedure, and group III (n=11) as normal baseline CTP with successful CS procedure. The demographics and baseline cognitive performances were similar among the three groups. In group II, there were significant improvement in Alzheimer Disease Assessment Scale (pre 6.8 ± 4.3 vs post 4.9 ± 2.8, p=0.033), Mini-Mental State Examination Score (pre 25.8 ± 3.8 vs post 27.4 ± 3.5, p=0.007), and Color Trail test A (pre 120.4 ± 73.9s vs post 95.8 ± 57.6s, p=0.004) after CS. In groups I and III, however, no significant difference was observed in any of the cognitive tests.

CONCLUSIONS

Successful CS improves neurocognitive function in asymptomatic ICA stenosis or occlusion with objective ipsilateral ischemia.

Update on surgical management for asymptomatic carotid stenosis

The management of asymptomatic carotid stenosis has been a topic of considerable debate. In this article, we aim to critically review the recent literature as it pertains to surgical management of asymptomatic carotid stenosis. We will explore the most recent trials looking at advancements in best medical therapy, as well as trials that compare traditional carotid endarterectomy to carotid stenting. In addition, we will review the current literature on surgical technique and perioperative risk management. Overall, our current recommendation is for surgical management of asymptomatic carotid disease for stenoses ≥ 80% in patients who are of reasonable perioperative risk.