Dataset Information

Comparing Long-term Mortality After Carotid Endarterectomy vs Carotid Stenting Using a Novel Instrumental Variable Method for Risk Adjustment in Observational Time-to-Event Data.

ABSTRACT:

Importance

Choosing between competing treatment options is difficult for patients and clinicians when results from randomized and observational studies are discordant. Observational real-world studies yield more generalizable evidence for decision making than randomized clinical trials, but unmeasured confounding, especially in time-to-event analyses, can limit validity.

Objectives

To compare long-term survival after carotid endarterectomy (CEA) and carotid artery stenting (CAS) in real-world practice using a novel instrumental variable method designed for time-to-event outcomes, and to compare the results with traditional risk-adjustment models used in observational research for survival analyses.

Design, setting, and participants

A multicenter cohort study was performed. The Vascular Quality Initiative, an observational quality improvement registry, was used to compare long-term mortality after CEA vs CAS. The study included 86 017 patients who underwent CEA (n = 73 312) or CAS (n = 12 705) between January 1, 2003, and December 31, 2016. Patients were followed up for long-term mortality assessment by linking the registry data to Medicare claims. Medicare claims data were available through September 31, 2015.

Exposure

Procedure type (CEA vs CAS).

Main outcomes and measures

The hazard ratios (HRs) of all-cause mortality using unadjusted, adjusted, propensity-matched, and instrumental variable methods were examined. The instrumental variable was the proportion of CEA among the total carotid procedures (endarterectomy and stenting) performed at each hospital in the 12 months before each patient's index operation and therefore varies over the study period.

Results

Participants who underwent CEA had a mean (SD) age of 70.3 (9.4) years compared with 69.1 (10.4) years for CAS, and most were men (44 191 [60.4%] for CEA and 8117 [63.9%] for CAS). The observed 5-year mortality was 12.8% (95% CI, 12.5%-13.2%) for CEA and 17.0% (95% CI, 16.0%-18.1%) for CAS. The unadjusted HR of mortality for CEA vs CAS was 0.67 (95% CI, 0.64-0.71), and Cox-adjusted and propensity-matched HRs were similar (0.69; 95% CI, 0.65-0.74 and 0.71; 95% CI, 0.65-0.77, respectively). These findings are comparable with published observational studies of CEA vs CAS. However, the association between CEA and mortality was more modest when estimated by instrumental variable analysis (HR, 0.83; 95% CI, 0.70-0.98), a finding similar to data reported in randomized clinical trials.

Conclusions and relevance

The study found a survival advantage associated with CEA over CAS in unadjusted and Cox-adjusted analyses. However, this finding was more modest when using an instrumental variable method designed for time-to-event outcomes for risk adjustment. The instrumental variable-based results were more similar to findings from randomized clinical trials, suggesting this method may provide less biased estimates of time-dependent outcomes in observational analyses.

SUBMITTER: Columbo JA

PROVIDER: S-EPMC6324509 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundCarotid artery stenting (CAS) and carotid endarterectomy (CEA) are alternative strategies for stroke prevention in patients with atherosclerotic carotid disease. CEA has been considered the first-line treatment for carotid stenosis worldwide, and the safety and efficacy of CAS compared to CEA remains in question.ObjectiveThe purpose of this study is to compare the practice and outcomes of CAS and CEA in a real-world setting within public university hospitals in Brazil.MethodsThis study will be a prospective 5-year analysis of treatment for atherosclerotic carotid stenosis with CEA and CAS performed at 5 centers affiliated with the Vascular Study Group at public university hospitals in Brazil. The indications for the procedures will be determined by each surgeon's individual discretion, in accordance with preoperative risk evaluation. The primary outcome measures will be (1) any in-hospital stroke or death, and (2) any per-procedural stroke, death, or myocardial infarction (MI). Patients undergoing CEA in conjunction with cardiac surgery will be excluded from the study. Multivariate logistic regression will be performed to identify predictors of stroke or death in patients undergoing CEA and CAS. All tests of significance will be performed at the .05 level. This study was approved by the Committee of Ethics in Research at the University Hospital of Ribeirao Preto Medical School, and in all other participating institutions linked to National Research System and National Board of Health in Brazil (Process 15695/2011).ResultsThis study is currently in the recruitment phase, and the final patient is expected to be enrolled by the end of 2018. We hope to recruit approximately 800 patients to the study. Analyses will focus on primary end points for patients that are allocated to each treatment group. During the per-procedural period, the occurrence of the primary end point components (stroke, MI, or death) for CAS and CEA will be analyzed for symptomatic or asymptomatic subjects.ConclusionsThe analyses of the primary endpoints (and all others variables of the study) are expected to be published in 2019 in a peer reviewed journal, and results will be presented at scientific meetings, with summary results published online. This study will obtain new data related to the quality of treatment for carotid disease in Brazil at the primary training centers of future vascular surgeons, but the initial data that will be obtained and published (with the outcomes and complications) are restricted to the first 30 days postprocedure. This time restriction limits the comparison of the results that relate to the main goal of treatment, which is to decrease the risk of stroke over 5 years. The purpose of the study group is to continue the monitoring of patient records, and evaluate the follow-up data in the 5 years following the initial evaluation. This study protocol will contribute very significantly to improving the care of patients with carotid disease, in addition to qualifying the level of assistance provided in public university hospitals in the state of São Paulo, Brazil.Trial registrationClinicaltrials.gov NCT02538276; https://www.clinicaltrials.gov/ct2/show/NCT02538276 (Archived by WebCite at http://www.webcitation.org/6m7APnFLD).

Project description:BackgroundThe Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST) found a higher risk of stroke after carotid artery stenting and a higher risk of myocardial infarction (MI) after carotid endarterectomy.Methods and resultsCardiac biomarkers and ECGs were performed before and 6 to 8 hours after either procedure and if there was clinical evidence of ischemia. In CREST, MI was defined as biomarker elevation plus either chest pain or ECG evidence of ischemia. An additional category of biomarker elevation with neither chest pain nor ECG abnormality was prespecified (biomarker+ only). Crude mortality and risk-adjusted mortality for MI and biomarker+ only were assessed during follow-up. Among 2502 patients, 14 MIs occurred in carotid artery stenting and 28 MIs in carotid endarterectomy (hazard ratio, 0.50; 95% confidence interval, 0.26 to 0.94; P=0.032) with a median biomarker ratio of 40 times the upper limit of normal. An additional 8 carotid artery stenting and 12 carotid endarterectomy patients had biomarker+ only (hazard ratio, 0.66; 95% confidence interval, 0.27 to 1.61; P=0.36), and their median biomarker ratio was 14 times the upper limit of normal. Compared with patients without biomarker elevation, mortality was higher over 4 years for those with MI (hazard ratio, 3.40; 95% confidence interval, 1.67 to 6.92) or biomarker+ only (hazard ratio, 3.57; 95% confidence interval, 1.46 to 8.68). After adjustment for baseline risk factors, both MI and biomarker+ only remained independently associated with increased mortality.ConclusionsIn patients randomized to carotid endarterectomy versus carotid artery stenting, both MI and biomarker+ only were more common with carotid endarterectomy. Although the levels of biomarker elevation were modest, both events were independently associated with increased future mortality and remain an important consideration in choosing the mode of carotid revascularization or medical therapy.Clinical trial registrationURL: http://www.ClinicalTrials.gov. Unique identifier: NCT00004732.

Project description:ObjectivesThe purpose of this study was to compare health-related quality of life (HRQOL) outcomes in patients treated with carotid artery stenting (CAS) versus carotid endarterectomy (CEA).BackgroundIn CREST (Carotid Revascularization Endarterectomy versus Stenting Trial), the largest randomized trial of carotid revascularization to date, there was no significant difference in the primary composite endpoint, but rates of stroke and myocardial infarction (MI) differed between CAS and CEA. To help guide individualized clinical decision making, we compared HRQOL among patients enrolled in the CREST study. We also performed exploratory analyses to evaluate the association between periprocedural complications and HRQOL.MethodsWe measured HRQOL at baseline, and after 2 weeks, 1 month, and 1 year among 2,502 patients randomly assigned to either CAS or CEA in the CREST study. The HRQOL was assessed using the Medical Outcomes Study Short-Form 36 (SF-36) and 6 disease-specific scales designed to study HRQOL in patients undergoing carotid revascularization.ResultsAt both 2 weeks and 1 month, CAS patients had better outcomes for multiple components of the SF-36, with large differences for role physical function, pain, and the physical component summary scale (all p < 0.01). On the disease-specific scales, CAS patients reported less difficulty with driving, eating/swallowing, neck pain, and headaches but more difficulty with walking and leg pain (all p < 0.05). However, by 1 year, there were no differences in any HRQOL measure between CAS and CEA. In the exploratory analyses, periprocedural stroke was associated with poorer 1-year HRQOL across all SF-36 domains, but periprocedural MI or cranial nerve palsy were not.ConclusionsAmong patients undergoing carotid revascularization, CAS is associated with better HRQOL during the early recovery period as compared with CEA-particularly with regard to physical limitations and pain-but these differences diminish over time and are not evident after 1 year. Although CAS and CEA are associated with similar overall HRQOL at 1 year, event-specific analyses confirm that stroke has a greater and more sustained impact on HRQOL than MI. (Carotid Revascularization Endarterectomy versus Stenting Trial [CREST]; NCT00004732)

Project description:Importance:The Carotid Revascularization Endarterectomy vs Stenting Trial (CREST) showed greater safety of carotid artery stenting (CAS) in patients younger than 70 years and carotid endarterectomy (CEA) in those older than 70 years. It is unknown how the result of CREST has influenced carotid revascularization choices in the United States. Objective:To evaluate national patterns in CAS performance in patients older than 70 years in the post-CREST (2011-2014) compared with the pre-CREST (2007-2010) era. Design, Setting, and Participants:All adults older than 70 years undergoing carotid revascularization in the United States from 2007 to 2014 were retrospectively identified from the 2007-2014 National Inpatient Sample using International Classification of Disease, Ninth Revision procedural codes. From 61 324 882 unweighted hospitalizations contained in the 2007-2014 National Inpatient Sample, 494 733 weighted carotid revascularization admissions in adults older than 70 years were identified using International Classification of Disease, Ninth Revision procedural codes. Main Outcomes and Measures:The proportion of CAS performed in all age groups over time was estimated and multivariable-adjusted models were used to compare the odds of receiving CAS in the pre-CREST with those in the post-CREST era in adults older than 70 years. Results:A total of 41.8% of all patients were women, and mean (SE) age at presentation was 78.1 (0.03) years. A total of 16.3% of CAS and 10.1% of CEA procedures were performed in patients with symptomatic stenosis. The proportion of patients older than 70 years receiving CAS increased from 11.9% in the pre-CREST to 13.8% in the post-CREST era (P = .005). In multivariable models, the odds of receiving CAS increased by 13% in all patients older than 70 years in the post-CREST compared with the pre-CREST period (odds ratio [OR], 1.13, 95% CI, 1.00-1.28, P = .04), including symptomatic women (OR, 1.31, 1.05-1.65, P = .02). Symptomatic stenosis (OR 1.39; 95% CI, 1.27-1.52; P < .001), congestive heart failure (OR, 1.48; 95% CI, 1.35-1.63; P < .001), and peripheral vascular disease (OR, 1.35; 95% CI, 1.27-1.43; P < .001) were associated with higher odds of CAS; comorbid hypertension (OR, 0.70; 95% CI, 0.66-0.74; P < .001), smoking (OR, 0.84; 95% CI, 0.78-0.91; P < .001), and weekend admission (OR, 0.77; 95% CI, 0.68-0.88; P < .001) were negatively associated with the odds of CAS. Conclusions and Relevance:Despite concerns for higher periprocedural complications with CAS in elderly patients, the odds of CAS increased in the post-CREST compared with pre-CREST era in patients older than 70 years, including symptomatic women.

Project description:BackgroundCarotid-artery stenting and carotid endarterectomy are both options for treating carotid-artery stenosis, an important cause of stroke.MethodsWe randomly assigned patients with symptomatic or asymptomatic carotid stenosis to undergo carotid-artery stenting or carotid endarterectomy. The primary composite end point was stroke, myocardial infarction, or death from any cause during the periprocedural period or any ipsilateral stroke within 4 years after randomization.ResultsFor 2502 patients over a median follow-up period of 2.5 years, there was no significant difference in the estimated 4-year rates of the primary end point between the stenting group and the endarterectomy group (7.2% and 6.8%, respectively; hazard ratio with stenting, 1.11; 95% confidence interval, 0.81 to 1.51; P=0.51). There was no differential treatment effect with regard to the primary end point according to symptomatic status (P=0.84) or sex (P=0.34). The 4-year rate of stroke or death was 6.4% with stenting and 4.7% with endarterectomy (hazard ratio, 1.50; P=0.03); the rates among symptomatic patients were 8.0% and 6.4% (hazard ratio, 1.37; P=0.14), and the rates among asymptomatic patients were 4.5% and 2.7% (hazard ratio, 1.86; P=0.07), respectively. Periprocedural rates of individual components of the end points differed between the stenting group and the endarterectomy group: for death (0.7% vs. 0.3%, P=0.18), for stroke (4.1% vs. 2.3%, P=0.01), and for myocardial infarction (1.1% vs. 2.3%, P=0.03). After this period, the incidences of ipsilateral stroke with stenting and with endarterectomy were similarly low (2.0% and 2.4%, respectively; P=0.85).ConclusionsAmong patients with symptomatic or asymptomatic carotid stenosis, the risk of the composite primary outcome of stroke, myocardial infarction, or death did not differ significantly in the group undergoing carotid-artery stenting and the group undergoing carotid endarterectomy. During the periprocedural period, there was a higher risk of stroke with stenting and a higher risk of myocardial infarction with endarterectomy. (ClinicalTrials.gov number, NCT00004732.)