Faculty Bibliography

BACKGROUND AND PURPOSE:Multicenter clinical trials attempt to select sites that can move rapidly to randomization and enroll sufficient numbers of patients. However, there are few assessments of the success of site selection. METHODS:In the CREST-2 (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trials), we assess factors associated with the time between site selection and authorization to randomize, the time between authorization to randomize and the first randomization, and the average number of randomizations per site per month. Potential factors included characteristics of the site, specialty of the principal investigator, and site type. RESULTS:For 147 sites, the median time between site selection to authorization to randomize was 9.9 months (interquartile range, 7.7, 12.4), and factors associated with early site activation were not identified. The median time between authorization to randomize and a randomization was 4.6 months (interquartile range, 2.6, 10.5). Sites with authorization to randomize in only the carotid endarterectomy study were slower to randomize, and other factors examined were not significantly associated with time-to-randomization. The recruitment rate was 0.26 (95% confidence interval, 0.23-0.28) patients per site per month. By univariate analysis, factors associated with faster recruitment were authorization to randomize in both trials, principal investigator specialties of interventional radiology and cardiology, pre-trial reported performance >50 carotid angioplasty and stenting procedures per year, status in the top half of recruitment in the CREST trial, and classification as a private health facility. Participation in StrokeNet was associated with slower recruitment as compared with the non-StrokeNet sites. CONCLUSIONS:Overall, selection of sites with high enrollment rates will likely require customization to align the sites selected to the factor under study in the trial. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT02089217.

BACKGROUND AND PURPOSE:Patients undergoing carotid endarterectomy (CEA) for symptomatic stenosis of the internal carotid artery benefit from early intervention. Heterogeneous data are available on the influence of timing of carotid artery stenting (CAS) on procedural risk. METHODS:We investigated the association between timing of treatment (0-7 days and >7 days after the qualifying neurological event) and the 30-day risk of stroke or death after CAS or CEA in a pooled analysis of individual patient data from 4 randomized trials by the Carotid Stenosis Trialists' Collaboration. Analyses were done per protocol. To obtain combined estimates, logistic mixed models were applied. RESULTS:value for interaction with time interval 0.06). CONCLUSIONS:In randomized trials comparing stenting with CEA for symptomatic carotid artery stenosis, CAS was associated with a substantially higher periprocedural risk during the first 7 days after the onset of symptoms. Early surgery is safer than stenting for preventing future stroke. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT00190398; URL: http://www.controlled-trials.com. Unique identifier: ISRCTN57874028; Unique identifier: ISRCTN25337470; URL: http://www.clinicaltrials.gov. Unique identifier: NCT00004732.

OBJECTIVE:To determine whether the obesity paradox exists in patients who undergo carotid artery stenting (CAS) or carotid endarterectomy (CEA) for symptomatic carotid artery stenosis. METHODS:. Primary outcome was stroke or death, investigated separately for the periprocedural and postprocedural period (≤120 days/>120 days after randomization). This outcome was compared between different BMI strata in CAS and CEA patients separately, and in the total group. We performed intention-to-treat multivariable Cox regression analyses. RESULTS:= 0.48). Within the total group, patients with BMI 25-<30 had lower postprocedural risk of stroke or death than patients with BMI 20-<25 (BMI 25-<30 vs BMI 20-<25; hazard ratio 0.72; 95% confidence interval 0.55-0.94). CONCLUSIONS:BMI is not associated with periprocedural risk of stroke or death; however, BMI 25-<30 is associated with lower postprocedural risk than BMI 20-<25. These observations were similar for CAS and CEA.

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.

Non-vitamin K antagonist oral anticoagulants (NOACs) are frequently used to prevent stroke in patients with atrial fibrillation. These patients are often also on aspirin or other antiplatelet agents. It is possible that treatment with both NOACs and aspirin or other antiplatelet drug may be effective in decreasing stroke, but data are sparse regarding the efficacy and safety of using both agents for stroke prevention.To address these issues, data were pooled from the four recent randomized controlled trials of NOACs apixaban, rivaroxaban, dabigatran and edoxaban, which included 42,411 patients; 14,148 (33.4%) were also on aspirin or other antiplatelet drug. The number of thromboembolic events among participants on NOAC and aspirin/antiplatelet was compared to the number of events in patients on NOAC alone. Bleeding rates were also compared among those on NOAC + aspirin/antiplatelet to NOAC alone. These results were compared to thromboembolic and bleeding events in the warfarin + aspirin/antiplatelet vs. warfarin alone. No greater risk for thromboembolism was seen in patients on NOACs compared to patients on both NOACs and aspirin/antiplatelet drug. In this non-randomized comparison, there was initially a signal towards higher thromboembolic rates among NOAC users also on aspirin/antiplatelet drugs (RR 1.16; 95% CI 1.05, 1.29) compared to NOAC alone. This likely reflected the higher CHADS2 scores of those on aspirin/antiplatelet drugs. When the analysis was limited to studies that included aspirin rather than other antiplatelet drugs, no difference was seen for thromboembolic rates comparing dual therapy to NOAC alone (RR 1.02; 95% CI 0.90, 1.15). Higher rates of bleeding were seen with aspirin/antiplatelet drug in conjunction with NOAC. In this meta-analysis and nonrandomized comparison of aspirin/antiplatelet users and nonusers also on anticoagulation, there was no additional benefit seen of anticoagulation and antiplatelet therapy for stroke 4 prevention compared to anticoagulation alone. There was, however, an increased risk of bleeding. Careful assessment of the indications for antiplatelet drugs in patients with atrial fibrillation who are also receiving oral anticoagulation is warranted, and future randomized comparisons are needed.

OBJECTIVE: The Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) demonstrated a higher periprocedural stroke and death (S+D) rate among patients randomized to carotid artery stenting (CAS) than to carotid endarterectomy (CEA). Herein, we seek factors that affect the CAS-CEA treatment differences and potentially to identify a subgroup of patients for whom CAS and CEA have equivalent periprocedural S+D risk. METHODS: Patient and arterial characteristics were assessed as effect modifiers of the CAS-CEA treatment difference in 2502 patients by the addition of factor-by-treatment interaction terms to a logistic regression model. RESULTS: Lesion length and lesions that were contiguous or were sequential and noncontiguous extending remote from the bulb were identified as influencing the CAS-to-CEA S+D treatment difference. For those with longer lesion length (>/=12.85 mm), the risk of CAS was higher than that of CEA (odds ratio [OR], 3.42; 95% confidence interval [CI], 1.19-9.78). Among patients with sequential or remote lesions extending beyond the bulb, the risk for S+D was higher for CAS relative to CEA (OR, 9.01; 95% CI, 1.20-67.8). For the 37% of patients with lesions that were both short and contiguous, the odds of S+D in those treated with CAS was nonsignificantly 28% lower than for CEA (OR, 0.72; 95% CI, 0.21-2.46). CONCLUSIONS: The higher S+D risk for those treated with CAS appears to be largely isolated to those with longer lesion length and/or those with sequential and remote lesions. In the absence of those lesion characteristics, CAS appears to be as safe as CEA with regard to periprocedural risk of S+D.

BACKGROUND: Age was reported to be an effect-modifier in four randomised controlled trials comparing carotid artery stenting (CAS) and carotid endarterectomy (CEA), with better CEA outcomes than CAS outcomes noted in the more elderly patients. We aimed to describe the association of age with treatment differences in symptomatic patients and provide age-specific estimates of the risk of stroke and death within narrow (5 year) age groups. METHODS: In this meta-analysis, we analysed individual patient-level data from four randomised controlled trials within the Carotid Stenosis Trialists' Collaboration (CSTC) involving patients with symptomatic carotid stenosis. We included only trials that randomly assigned patients to CAS or CEA and only patients with symptomatic stenosis. We assessed rates of stroke or death in 5-year age groups in the periprocedural period (between randomisation and 120 days) and ipsilateral stroke during long-term follow-up for patients assigned to CAS or CEA. We also assessed differences between CAS and CEA. All analyses were done on an intention-to-treat basis. FINDINGS: Collectively, 4754 patients were randomly assigned to either CEA or CAS treatment in the four studies. 433 events occurred over a median follow-up of 2.7 years. For patients assigned to CAS, the periprocedural hazard ratio (HR) for stroke and death in patients aged 65-69 years compared with patients younger than 60 years was 2.16 (95% CI 1.13-4.13), with HRs of roughly 4.0 for patients aged 70 years or older. We noted no evidence of an increased periprocedural risk by age group in the CEA group (p=0.34). These changes underpinned a CAS-versus CEA periprocedural HR of 1.61 (95% CI 0.90-2.88) for patients aged 65-69 years and an HR of 2.09 (1.32-3.32) for patients aged 70-74 years. Age was not associated with the postprocedural stroke risk either within treatment group (p>/=0.09 for CAS and 0.83 for CEA), or between treatment groups (p=0.84). INTERPRETATION: In these RCTs, CEA was clearly superior to CAS in patients aged 70-74 years and older. The difference in older patients was almost wholly attributable to increasing periprocedural stroke risk in patients treated with CAS. Age had little effect on CEA periprocedural risk or on postprocedural risk after either procedure. FUNDING: None.

BACKGROUND: In the Carotid Revascularization Endarterectomy versus Stenting Trial, we found no significant difference between the stenting group and the endarterectomy group with respect to the primary composite end point of stroke, myocardial infarction, or death during the periprocedural period or any subsequent ipsilateral stroke during 4 years of follow-up. We now extend the results to 10 years. METHODS: Among patients with carotid-artery stenosis who had been randomly assigned to stenting or endarterectomy, we evaluated outcomes every 6 months for up to 10 years at 117 centers. In addition to assessing the primary composite end point, we assessed the primary end point for the long-term extension study, which was ipsilateral stroke after the periprocedural period. RESULTS: Among 2502 patients, there was no significant difference in the rate of the primary composite end point between the stenting group (11.8%; 95% confidence interval [CI], 9.1 to 14.8) and the endarterectomy group (9.9%; 95% CI, 7.9 to 12.2) over 10 years of follow-up (hazard ratio, 1.10; 95% CI, 0.83 to 1.44). With respect to the primary long-term end point, postprocedural ipsilateral stroke over the 10-year follow-up occurred in 6.9% (95% CI, 4.4 to 9.7) of the patients in the stenting group and in 5.6% (95% CI, 3.7 to 7.6) of those in the endarterectomy group; the rates did not differ significantly between the groups (hazard ratio, 0.99; 95% CI, 0.64 to 1.52). No significant between-group differences with respect to either end point were detected when symptomatic patients and asymptomatic patients were analyzed separately. CONCLUSIONS: Over 10 years of follow-up, we did not find a significant difference between patients who underwent stenting and those who underwent endarterectomy with respect to the risk of periprocedural stroke, myocardial infarction, or death and subsequent ipsilateral stroke. The rate of postprocedural ipsilateral stroke also did not differ between groups. (Funded by the National Institutes of Health and Abbott Vascular Solutions; CREST ClinicalTrials.gov number, NCT00004732.).