Sex Differences in Plaque Composition and Morphology Among Symptomatic Patients With Mild-to-Moderate Carotid Artery Stenosis.

BACKGROUND AND PURPOSE: Incidence of ischemic stroke differs between men and women, with substantially higher rates in men. The underlying mechanism of this difference remains poorly understood but may be because of differences in carotid atherosclerosis. Using an in-depth imaging-based approach, we investigated differences between carotid plaque composition and morphology in male and female patients with stroke, taking into account differences in total plaque burden. Additionally, we investigated all possible within-artery combinations of plaque characteristics to explore differences between various plaque phenotypes. METHODS: We included 156 men and 68 women from the PARISK (Plaque At Risk) study, a prospective cohort study of patients with recent ischemic cerebrovascular symptoms and <70% ipsilateral carotid stenosis. Plaque characteristics (intraplaque hemorrhage [IPH], lipid-rich necrotic core [LRNC], calcifications, thin-or-ruptured fibrous cap, ulcerations, total plaque volume) were assessed with magnetic resonance imaging and multidetector-row computed tomography angiography. We used multivariable logistic and linear regression analyses to assess sex differences in plaque characteristics. RESULTS: We found significant difference in total plaque volume between men and women (ß=22.9 mm3 [95% CI, 15.4-30.5]; mean volume in men 1399±425 mm3, in women 1011±242 mm3). Additionally, men were more likely to have IPH (odds ratio [OR]=2.8 [95% CI, 1.3-6.3]; IPH proportion in men 49%, in women 16%) and LRNC (OR=2.4 [95% CI, 1.2-4.7]; LRNC proportion in men 73%, in women 41%) even after adjustment for total plaque volume. We found no sex-specific differences in plaque volume-corrected volumes of IPH, LRNC, and calcifications. In terms of coexistence of plaque characteristics, we found that men had more often a plaque with coexistence of calcifications, LRNC, and IPH (OR=2.7 [95% CI, 1.2-7.0]), with coexistence of thin-or-ruptured fibrous cap/ulcerations, LRNC, and IPH (OR=2.4 [95% CI, 1.1-5.9]), and with coexistence of all plaque characteristics (OR=3.0 [95% CI, 1.2-8.6]). CONCLUSIONS: In symptomatic patients with mild-to-moderate carotid stenosis, men are more likely to have a high-risk carotid plaque with IPH and LRNC than women, regardless of total plaque burden. Men also have more often a plaque with multiple vulnerable plaque components, which could comprise an even higher stroke risk. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01208025.

[Assessment of peripheral artery disease in proven coronary patients in Abidjan Heart Institute of Côte d'Ivoire]. / Évaluation des lésions artérielles périphériques chez le coronarien avéré à l'Institut de cardiologie d'Abidjan en Côte d'Ivoire.

BACKGROUND: Coronary artery disease is mainly due to atherosclerosis. The aim of this study was to evaluate the frequency of peripheral arterial disease in proven coronary artery disease and to determine the associated factors in our context. MATERIAL AND METHODS: We included in a cross-sectional descriptive and analytical study 224 patients with proven coronary artery disease confirmed on coronary angiography from March 1 to October 30, 2019. It took place in the external exploration department of the Abidjan Heart Institute. An ultrasonographic exploration of the supra-aortic trunks and arteries of the lower extremity with measurement of the ankle brachial index (ABI) was carried out. RESULTS: The mean age was 57.4±10.9 years (27-81years). There was a clear male predominance with a sex-ratio of 5. The prevalence of carotid artery disease was 56.4% of patients. The main factors associated with elevated Intima Media Thickness (IMT) and the presence of carotid plaques were male sex (OR=8.8; P=0.038), smoking (OR=2.5; P=0.049) and multi-truncular involvement (OR=3.2; P=0.014). In the lower extremities, there was a prevalence of peripheral arterial disease of 48.5%. The main factors associated with the decrease of ABI were age ≥50 years (OR=2.6; P=0.043), diabetes (OR=2.8; P=0.02), dyslipidemia (OR=3.8; P=0.001) and pluri-truncular involvement (OR=4.5; P<0.0001). CONCLUSION: The presence of significant coronary artery disease in our context is associated with a high prevalence of peripheral carotid artery and lower extremity artery disease. This is all the more so as we are male, over 50 years old, pluri-truncular with many cardiovascular risk factors.

Cost Effectiveness of Assessing Ultrasound Plaque Characteristics to Risk Stratify Asymptomatic Patients With Carotid Stenosis.

Background Imaging may play an important role in identifying high-risk plaques in patients who have carotid disease and who could benefit from surgical revascularization. We sought to evaluate the cost effectiveness of a decision-making rule based on the ultrasound imaging assessment of plaque echolucency in patients with asymptomatic carotid stenosis. Methods and Results We used a decision-analytic model to project lifetime quality-adjusted life years and costs for 5 stroke prevention strategies: (1) medical therapy only; (2) revascularization if both plaque echolucency and stenosis progression to >90% are present; (3) revascularization only if plaque echolucency is present; (4) revascularization only if stenosis progression >90% is present; or (5) either plaque echolucency or stenosis progression is present. Risks of clinical events, costs, and quality-of-life values were estimated based on published sources and the analysis was conducted from a healthcare system perspective for asymptomatic patients with 70% to 89% carotid stenosis at presentation. Patients who did not undergo revascularization had the highest stroke events (17.6%) and lowest life-years (8.45), while those who underwent revascularization on the basis of either presence of plaque echolucency on ultrasound or progression of carotid stenosis had the lowest stroke events (12.0%) and longest life-years (14.41). The either plaque echolucency or progression-based revascularization group had an incremental cost-effectiveness ratio of $110 000/quality-adjusted life years compared with the plaque echolucency-based strategy, which had an incremental cost-effectiveness ratio of $29 000/quality-adjusted life years compared with the joint echolucency and progression-based strategy. Conclusions Plaque echolucency on ultrasound can be a cost-effective tool to identify patients with asymptomatic carotid artery stenosis most likely to benefit from carotid endarterectomy.

Application of a decision tree to establish factors associated with a nomogram of aortic stiffness.

Aortic stiffness is a marker of vascular aging and may reflect occurrence of cardiovascular (CV) diseases. Aortic pulse wave velocity (PWV), a marker of aortic stiffness, can be measured by applanation tonometry. A nomogram of aortic stiffness was evaluated by the calculation of PWV index. Theoretical PWV can be calculated according to age, gender, mean blood pressure, and heart rate, allowing to form an individual PWV index [(measured PWV - theoretical PWV)/theoretical PWV]. The purpose of the present cross-sectional study was to investigate the determinants of the PWV index, by applying a decision tree. A cross-sectional study was conducted from 2012 to 2017, and 597 individuals were included. A training decision tree was constructed based on seventy percent of these subjects (N = 428). The remaining 30% (N = 169) were used as the testing dataset to evaluate the performance of the decision trees. The input variables for the models were clinical and biochemical parameters. The different input variables remained in the model were diabetes, tobacco status, carotid plaque, albuminuria, C-reactive protein, total cholesterol, BMI, and previous CV diseases. For the validation decision model, the sensitivity, specificity, and accuracy values for identifying the related risk factors of PWV index were 70%, 78%, and 0.73. Since determinants of PWV index were all well-accepted CV risk factors, a nomogram of aortic stiffness could be considered as an integrator of CV risk factors on their duration of exposure and could be utilized to develop future programs for CV risk assessment and reduction strategies.

Clinical Effect and Cost-Effectiveness of Screening for Asymptomatic Carotid Stenosis: A Markov Model.

OBJECTIVE/BACKGROUND: The cost-effectiveness of screening depends on the cost of screening, prevalence of asymptomatic carotid artery stenosis (ACAS), and the potential effect of medical intervention in reducing the risk of stroke. The aim of the study was to determine the threshold values for these parameters in order for screening for ACAS to be cost-effective. METHODS: The clinical effect and cost-effectiveness of ultrasound screening for ACAS with subsequent initiation of preventive therapy versus not screening was assessed in a Markov model with a lifetime perspective. Key parameters, including stroke risk, all cause mortality, and costs, were based on contemporary published data, population statistics, and data from an ongoing screening program in Uppsala county (population 300,000), Sweden. Prevalence of ACAS (2%) and the rate of best medical treatment (BMT; 40%) were based on data from a male Swedish population recently screened for ACAS. The required stroke risk reduction from BMT, incremental cost-efficiency ratio (ICER), absolute risk reduction for stroke (ARR), and number needed to screen (NNS) were calculated. RESULTS: Screening was cost-effective at an ICER of €5744 per incremental quality adjusted life year (QALY) gained. ARR was 135 per 100,000 screened, NNS was 741, and QALYs gained were 6700 per 100,000 invited. At a willingness to pay (WTP) threshold of €50,000 per QALY the minimum required stroke risk reduction from BMT was 22%. The assumed degree of stroke risk reduction was the most important determinant of cost-efficiency. CONCLUSION: A moderate (22%) reduction in the risk of stroke was required for an ACAS screening strategy to be cost-effective at a WTP of €50,000/QALY. Targeting populations with a higher prevalence of ACAS could further improve cost-efficiency.

Carotid Ultrasound for Assessment of Nonobstructive Carotid Atherosclerosis in Young Adults with Cryptogenic Stroke.

BACKGROUND: The role of nonobstructive (<50% stenosis) carotid atherosclerosis (NOCA) in young adults with ischemic stroke is not well understood. In the present study, we investigated the prevalence and the ultrasonic characteristics of NOCA in a consecutive series of young adults with cryptogenic stroke (CS). METHODS: Patients aged 18-54, consecutively treated in a tertiary hospital for first-ever CS (defined as an ischemic stroke without ASCOD (A: atherosclerosis; S: small-vessel disease; C: cardiac pathology; O: other causes) grade 1 potential cause) in the carotid artery territory, were prospectively enrolled. NOCA was assessed using carotid duplex ultrasonography. RESULTS: Of 148 patients with first-ever ischemic stroke, 70 had CS, including 44 patients with carotid CS. NOCA was found in 22 of 44 (50%) patients. All but 1 plaque were echolucent. NOCA was bilateral in 15 patients and unilateral in 7 patients. All unilateral plaques were on the symptomatic side (P = .02). Plaque thickness, plaque length, and plaque volume were greater on the symptomatic side than on the asymptomatic side (P = .001, P < .001, and P < .001, respectively). Discrimination between the symptomatic and the asymptomatic side using any of these plaque metrics was good with areas under the curve (95% confidence interval) of .82 (.69-0.95), .85 (.74-0.96), and .87 (.75-0.99) for plaque thickness, plaque length, and plaque volume, respectively. CONCLUSIONS: NOCA is frequent in young adults with CS. Measurement of the plaque burden with carotid duplex may help to identify symptomatic NOCA.

Web-based accurate measurements of carotid lumen diameter and stenosis severity: An ultrasound-based clinical tool for stroke risk assessment during multicenter clinical trials.

BACKGROUND: This pilot study presents a completely automated, novel, smart, cloud-based, point-of-care system for (a) carotid lumen diameter (LD); (b) stenosis severity index (SSI) and (c) total lumen area (TLA) measurement using B-mode ultrasound. The proposed system was (i) validated against manual reading taken by the Neurologist and (ii) benchmarked against the commercially available system. METHOD: One hundred patients (73 M/27 F, mean age: 68 ± 11 years), institutional review board approved, written informed consent, consisted of left/right common carotid artery (200 ultrasound scans) were acquired using a 7.5-MHz linear transducer. RESULTS: The measured mean LD for left and right carotids were (in mm): (i) for proposed system (6.49 ± 1.77, 6.66 ± 1.70); and (ii) for manual (6.29 ± 1.79, 6.45 ± 1.63), respectively and coefficient of correlation between cloud-based automated against manual were 0.98 (P < 0.0001) and 0.99 (P < 0.0001), respectively. The corresponding TLA error, Precision-of-Merit, and Figure-of-Merit when measured against the manual were: 4.56 ± 3.54%, 96.18 ± 3.21%, and 96.85%, respectively. The AUC for the receiving operating characteristics for the cloud-based system was: 1.0. Four statistical tests such as: Two-tailed z-test, Mann-Whitney test, Kolmogorov-Smirnov (KS) and one-way ANOVA were performed to demonstrate consistency and reliability. CONCLUSIONS: The proposed system is reliable, accurate, fast, completely automated, anytime-anywhere solution for multi-center clinical trials and routine vascular screening.

High Prevalence of Multiple Arterial Bed Lesions in Patients With Fibromuscular Dysplasia: The ARCADIA Registry (Assessment of Renal and Cervical Artery Dysplasia).

Fibromuscular dysplasia (FMD) commonly affects the renal and cervical arteries but has been described to affect other vascular beds as well. The prevalence of and clinical characteristics associated with multisite FMD (string-of-beds or focal stenoses affecting at least 2 vascular beds) are not known. In the prospective ARCADIA registry (Assessment of Renal and Cervical Artery Dysplasia), symptomatic patients with renal artery (RA) FMD underwent tomographic- or magnetic resonance-angiography from the aortic arch to the intracranial arteries and those with cervical FMD from the diaphragm to the pelvis. Of 469 patients (84.0% women), 225 (48.0%) had multisite FMD. In addition, 86 of 244 patients with single-site disease had dissections or aneurisms affecting other vascular beds, totaling 311 patients (66.3%) with lesions in >1 vascular bed. Among patients with a cerebrovascular presentation, the prevalence of RA lesions was higher in patients with than in those without hypertension (odds ratio, 3.4; 95% confidence interval, 1.99-6.15). Among patients with a renal presentation, the prevalence of cervical lesions was higher in patients with bilateral than in those with unilateral RA lesions (odds ratio, 1.9; 95% confidence interval, 0.99-3.57). In conclusion, FMD is a systemic arterial disease. At least 2 vascular beds were affected by dysplastic stenoses in 48.0% of cases and by dysplastic stenoses, aneurysms, and dissections in 66.1% of cases. RA imaging should be proposed to hypertensive patients with a cerebrovascular presentation. Cervical artery imaging should be considered in patients with a renal presentation and bilateral RA lesions. CLINICAL TRIAL REGISTRATION: URL: www.Clinicaltrials.gov. Unique identifier: NCT02884141.

Investigation into drivers of cost of stenting for carotid stenosis.

OBJECTIVE: We aimed to identify factors associated with cost of carotid artery stenting (CAS). METHODS: Patient and hospital characteristics affecting cost of admission for CAS were identified using the Vizient national database of hospital-reported outcomes. Patients who underwent CAS for either asymptomatic or symptomatic carotid stenosis were identified using surgical Medicare Severity-Diagnosis Related Groups and appropriate International Classification of Diseases, Ninth Revision and Tenth Revision codes. RESULTS: There were 166 hospitals that reported outcomes from 7369 inpatient admissions for CAS. Each institution reported a mean value for cost related to patient care per admission for CAS; the average cost across all reporting institutions was $12,834.14 (standard error of the mean [SEM], 492.88). Institutions in the lowest 25th percentile with respect to frequency of intensive care unit admission after CAS had lower cost of admission than institutions above the 75th percentile ($10,971.30 [SEM, 460.67] vs $14,992.90 [964.29]; P = .002), without any differences in incidence of stroke during admission (2.2% [SEM, 0.3] vs 2.0% [0.4]; P = .877) or 30-day readmission (1.9% [SEM, 0.4] vs 2.5 [0.6]; P = .329). Admissions for patients with symptomatic stenosis were more expensive than those with asymptomatic stenosis ($20,462.10 [SEM, 819.93] vs $11,285.20 [347.11]; P < .001). Obesity was also associated with greater costs of admission ($14,176.20 [SEM, 597.13] vs $12,287.10 [395.73]; P < .001). CONCLUSIONS: Admission to an intensive care unit, symptomatic stenosis, and obesity were associated with increased costs in patients undergoing CAS. These data may aid in identifying opportunities to improve the cost-effectiveness of this procedure.

Assessment of 'on-treatment platelet reactivity' and relationship with cerebral micro-embolic signals in asymptomatic and symptomatic carotid stenosis.

INTRODUCTION: The relationship between on-treatment platelet reactivity and cerebral micro-embolic signals (MES) is unknown, and has not been previously simultaneously assessed in asymptomatic and symptomatic carotid stenosis patients. METHODS: Consecutive eligible patients with ≥50% asymptomatic or recently symptomatic carotid stenosis (≤4weeks following TIA/ischaemic stroke) were recruited to this pilot study. Symptomatic patients were followed up to the 'late' phase (≥3months) following symptom onset or carotid intervention; longitudinal data were analysed from symptomatic patients with data available at both time-points. Platelet function/reactivity was assessed with the PFA-100® to measure collagen-ADP (C-ADP) and collagen-epinephrine (C-EPI) closure times in citrate-anticoagulated whole blood. Bilateral simultaneous 1-hour transcranial Doppler ultrasound (TCD) monitoring of the middle cerebral arteries was performed to classify patients as MES +ve or MES -ve. RESULTS: 31 patients with ≥50% asymptomatic and 46 with early symptomatic carotid stenosis or occlusion were included. 35 symptomatic patients were followed up to the late phase (23 following carotid intervention). Prevalence of 'high on-treatment platelet reactivity' (HTPR) on the C-EPI cartridge did not differ between asymptomatic and symptomatic patients overall, but was lower in 'symptomatic post-intervention' than asymptomatic patients on aspirin monotherapy (10% vs. 50%; p=0.03). The prevalence of HTPR on the C-EPI cartridge decreased between the early and late phases in symptomatic patients (63% vs. 34%; p=0.017), including those on aspirin monotherapy (p=0.016). There were no significant differences in HTPR status between asymptomatic vs. early or late symptomatic MES +ve or MES -ve patients. DISCUSSION: Carotid interventional treatment, presumably in combination with resolution of the acute phase response, may decrease the prevalence of HTPR in patients with recently symptomatic carotid stenosis over time. Preliminary subgroup analysis suggests that successful intervention may reduce the prevalence of aspirin-HTPR in symptomatic patients to lower levels than asymptomatic medically-treated patients on aspirin monotherapy. Larger, longitudinal studies are warranted to reassess the impact of more intensive secondary preventive treatment on ex vivo platelet function at different levels of shear stress in carotid stenosis patients.

The Association between Ideal Cardiovascular Health Metrics and Extracranial Carotid Artery Stenosis in a Northern Chinese Population: A Cross-Sectional Study.

Past epidemiologic studies have indicated that the ideal cardiovascular health (CVH) metrics are associated with a lower risk of cardiovascular diseases (CVDs) and stroke. Carotid artery stenosis (CAS) causes approximately 10% of ischemic strokes. The association between ideal CVH and extracranial CAS has not yet been assessed. In the current study, extracranial CAS was assessed by carotid duplex ultrasonography. Logistic regression was used to analyze the association between ideal CVH metrics and extracranial CAS. A total of 3297 participants (52.2% women) aged 40 years and older were selected from the Jidong community in China. After adjusting for sex, age and other potential confounds, the odds ratios (95% confidence intervals) for extracranial CAS were 0.57 (0.39-0.84), 0.46 (0.26-0.80) and 0.29 (0.15-0.54), and for those quartiles, quartile 2 (9-10), quartile 3 (11) and quartile 4 (12-14), respectively, compared with quartile 1 (≤8). This negative correlation was particularly evident in women and the elderly (≥60 years). This cross-sectional study showed a negative correlation between the ideal CVH metrics and the prevalence of extracranial CAS in northern Chinese adults.

Gender differences in patients with carotid stenosis.

This overview analyses gender differences in prevalence, epidemiology, risk factors and therapy in patients with carotid stenosis in a systematic review. Ischemic stroke is a leading cause of death in Western society, where about 20% of cases are triggered by a carotid stenosis or occlusion, which occurs more frequently in men than in women. The stroke-protective effect of carotid endarterectomy is greater in men. Men have lower peri-procedural stroke and death rates. Particularly men with carotid stenosis and a life expectancy of at least 5 years benefit from surgical treatment. Also, the recurrence rate of ipsilateral stroke 5 years after initial surgery is lower in men than in women. It is not yet fully clarified whether there are significant gender differences regarding the outcome after endovascular versus surgical treatment. Gender differences in the outcome of carotid artery repair may be caused by biological, anatomical (smaller vessel diameter in women) or hormonal differences as well as a protracted development of atherosclerotic changes in women and different plaque morphology. Moreover, women are on average older at the time of surgery and their surgical treatment is often delayed. To reduce the risk of stroke and to improve treatment outcome especially for women, further research on gender differences and their causes is mandatory and promising.

Prevalence of carotid artery stenosis in neurologically asymptomatic patients undergoing coronary artery bypass grafting for coronary artery disease: Role of anesthesiologist in preoperative assessment and intraoperative management.

OBJECTIVE(S): This study aimed to determine the prevalence of carotid artery stenosis (CAS) due to atherosclerosis in neurologically asymptomatic patients undergoing coronary artery bypass grafting (CABG) for coronary artery disease (CAD). It contemplated a greater role for the cardiac anesthesiologist in the perioperative management of such patients with either previously undiagnosed carotid artery disease or towards re-assessment of severity of CAS. DESIGN: Prospective, observational clinical study. SETTING: Operation room of a cardiac surgery centre of a tertiary teaching hospital. PARTICIPANTS: A hundred adult patients with New York Heart Association (NYHA) classification I to III presenting electively for CABG. INTERVENTIONS: All patients included in this study were subjected to ultrasonic examination by means of acarotid doppler scan to access for presence of CAS just prior to induction of general anesthesia. MEASUREMENTS AND MAIN RESULTS: Based on parameters measured using carotid doppler, the presence of CAS was defined using standard criteria. The prevalence of CAS was found to be as high as 38% amongst the patients included in our study. The risk factors for CAS were identified to be advanced age, history of smoking, diabetes mellitus, dyslipidaemia and presence of a carotid bruit. CONCLUSION: This study points towards the relatively wide prevalence of carotid artery disease in neurologically asymptomatic patients undergoing CABG for CAD in the elective setting. It highlights the need to routinely incorporate carotid ultrasonography in the armamentarium of the cardiac anesthesiologist as standard of care for all patients presenting for CABG.

Physician specialty and variation in carotid revascularization technique selected for Medicare patients.

OBJECTIVE: Carotid artery stenting (CAS) has become an alternative to carotid endarterectomy (CEA) for select patients with carotid atherosclerosis. We hypothesized that the choice of CAS vs CEA varies as a function of treating physician specialty, which would result in regional variation in the relative use of these treatment types. METHODS: We used Medicare claims (2002-2010) to calculate annual rates of CAS and CEA and examined changes by procedure type over time. To assess regional preferences surrounding CAS, we calculated the proportion of revascularizations by CAS, across hospital referral regions, defined according to the Dartmouth Atlas of Healthcare. We then examined relationships between patient factors, physician specialty, and regional use of CAS. RESULTS: The annual number of all carotid revascularization procedures decreased by 30% from 2002 to 2010 (3.2 to 2.3 per 1000; P = .005). Whereas rates of CEA declined by 35% during these 8 years (3.0 to 1.9 per 1000; P < .001), CAS utilization increased by 5% during the same interval (0.30 to 0.32 per 1000; P = .014). Variation in utilization of carotid revascularization varied across the Unites States, with some regions performing as few as 0.7 carotid procedure per 1000 beneficiaries (Honolulu, Hawaii) and others performing nearly 8 times as many (5.3 per 1000 in Houma, La). Variation in procedure type (CEA vs CAS) was evident as well, as the proportion of carotid revascularization procedures that were constituted by CAS varied from 0% (Casper, Wyo, and Meridian, Miss) to 53% (Bend, Ore). The majority of CAS procedures were performed by cardiologists (49% of all CAS cases), who doubled their rates of CAS during the study period from 0.07 per 1000 in 2002 to 0.15 per 1000 in 2010. CONCLUSIONS: Variation in rates of carotid revascularization exists. Whereas rates of carotid revascularization have declined by more than 30% in recent years, utilization of CAS has increased. The proportion of all carotid revascularization procedures performed as CAS varies markedly by geographic region, and regions with the highest proportion of cardiologists perform the most CAS procedures. Evidence-based guidelines for carotid revascularization will require a multidisciplinary approach to ensure uniform adoption across specialties that care for patients with carotid artery disease.

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.

Relationship Between Physician and Hospital Procedure Volume and Mortality After Carotid Artery Stenting Among Medicare Beneficiaries.

BACKGROUND: Clinical trials demonstrated the efficacy of carotid artery stenting (CAS) relative to carotid endarterectomy when performed by physicians with demonstrated proficiency. It is unclear how CAS performance may be influenced by the diversity in CAS and non-CAS provider volumes in routine clinical practice. METHODS AND RESULTS: We linked Medicare claims to the Centers for Medicare and Medicaid Services' CAS Database (2005-2009). We assessed the association between 30-day mortality and past-year physician (0, 1-4, 5-9, 10-19, ≥20) and hospital (<10, 10-19, 20-39, ≥40) CAS volumes and past-year hospital coronary and peripheral stenting volumes (<200, 200-399, 400-849, ≥850) among beneficiaries at least 66 years of age. Unadjusted 30-day mortality risk was 1.8% (95% confidence interval [CI], 1.6-2.0) for 19 724 patients undergoing CAS by 2045 physicians in 729 hospitals. Median past-year CAS volume was 9 (interquartile range, 4-19) for physicians and 23 (interquartile range, 12-41) for hospitals. Compared to physicians performing ≥20 CAS in the past year, lower CAS volumes were associated with higher adjusted risks of 30-day morality (P value for trend < 0.05): 1.4 (95% CI, 0.9-2.3) for 0 past-year CAS, 1.3 (95% CI, 0.9-1.8) for 1 to 4, 1.1 (95% CI, 0.8-1.6) for 5 to 9, and 0.9 (95% CI, 0.7-1.4) for 10 to 19. An inverse relationship between 30-day mortality and past-year CAS hospital volume as well as past-year hospital non-CAS volume, past-year hospital non-CAS volume, and 30-day mortality was also noted. CONCLUSIONS: Among Medicare patients, an inverse relationship exists between physician and hospital CAS volumes and hospital non-CAS stenting volume and 30-day mortality, even after adjusting for all pertinent patient- and hospital-level factors.

The Association of Publication of Center for Medicaid and Medicare Services Guidelines for Carotid Artery Angioplasty and Stenting (CAS) and CREST Results on the Utilization of CAS in Carotid Revascularization.

BACKGROUND: Since the 2004 approval of carotid artery angioplasty and stenting (CAS), there have been 2 seminal publications about CAS reimbursement (Center for Medicaid and Medicare Several guidelines [CMSG]; 2008) and clinical outcomes (Carotid Revascularization Endarterectomy versus Stent Trial [CREST]; 2010). We explored trends in CAS utilization after these publications nationally. METHODS: The most recent datasets of the nationwide inpatient sample (NIS) was queried for patients undergoing carotid revascularization. Utilization proportions of CAS were calculated quarterly from 2005 to 2011 for NIS. Three-time intervals related to CMSG and CREST publication were selected 2005-2008, 2008-2010, and after 2010. Logistic regression with piecewise linear trend for time was used to estimate different trends in CAS utilization for overall samples and for neurologically asymptomatic and symptomatic cases. RESULTS: The majority (95%) of the carotid revascularizations were performed on asymptomatic patients. Overall, CAS utilization constituted 12.5% of carotid revascularization procedures with a significant period increase of CAS; from 9.4% to 14%; P < 0.001. There was a small but significant decrease in the rate of CAS utilization after CMSG were published corresponding to a 2% decline in the odds ratio (OR) of CAS per quarter (OR, 0.98; 95% confidence interval, 0.97-0.99; P = 0.001). After CREST, CAS utilization continued to increase in both NIS but the rate of increase did not change significantly from the prepublication to the postpublication time interval. The odds of in-hospital mortality and postoperative stroke were independently and significantly higher for CAS patients in both overall and within the symptomatic cohorts. In all 3 periods of the study, and compared to carotid endarterectomy, the odds of mortality and postoperative stroke were significantly higher among patients who underwent CAS. CONCLUSIONS: Although overall utilization of CAS increased since 2005, it was not uniformly associated by the publication of CMSG or CREST. Despite increased utilization, the odds of adverse outcomes were independently higher among CAS patients.

Readmissions after carotid artery revascularization in the Medicare population.

BACKGROUND: In appropriately selected patients with severe carotid stenosis, carotid revascularization reduces ischemic stroke. Prior clinical research has focused on the efficacy and safety of carotid revascularization, but few investigators have considered readmission as a clinically important outcome. OBJECTIVES: The aims of this study were to examine frequency, timing, and diagnoses of 30-day readmission following carotid revascularization; to assess differences in 30-day readmission between patients undergoing carotid endarterectomy (CEA) and carotid artery stenting (CAS); to describe hospital variation in risk-standardized readmission rates (RSRR); and to examine whether hospital variation in the choice of procedure (CEA vs. CAS) is associated with differences in RSRRs. METHODS: We used Medicare fee-for-service administrative claims data to identify acute care hospitalizations for CEA and CAS from 2009 to 2011. We calculated crude 30-day all-cause hospital readmissions following carotid revascularization. To assess differences in readmission after CAS compared with CEA, we used Kaplan-Meier survival curves and fitted mixed-effects logistic regression. We estimated hospital RSRRs using hierarchical generalized logistic regression. We stratified hospitals into 5 groups by their proportional CAS use and compared hospital group median RSRRs. RESULTS: Of 180,059 revascularizations from 2,287 hospitals, CEA and CAS were performed in 81.5% and 18.5% of cases, respectively. The unadjusted 30-day readmission rate following carotid revascularization was 9.6%. Readmission risk after CAS was greater than that after CEA. There was modest hospital-level variation in 30-day RSRRs (median: 9.5%; range 7.5% to 12.5%). Variation in proportional use of CAS was not associated with differences in hospital RSRR (range of median RSRR across hospital groups 9.49% to 9.55%; p = 0.771). CONCLUSIONS: Almost 10% of Medicare patients undergoing carotid revascularization were readmitted within 30 days of discharge. Compared with CEA, CAS was associated with a greater readmission risk. However, hospitals' RSRR did not differ by their proportional CAS use.