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Durability of Stroke Prevention with Carotid Endarterectomy and Carotid Stenting

Published:September 18, 2018DOI:https://doi.org/10.1016/j.surg.2018.06.041

      Abstract

      Background

      Carotid artery stenting remains an effective alternative to carotid endarterectomy for stroke prevention; however, the long-term durability of carotid artery stenting remains poorly defined. We performed a 10-year “real-world” comparative analysis of carotid endarterectomy and carotid artery stenting to help evaluate the success of these procedures in preventing late ischemic stroke events.

      Methods

      This was a single-center retrospective review of 996 patients (symptomatic and asymptomatic) treated with carotid endarterectomy or carotid artery stenting from January 2001 through December 2011 at a tertiary academic medical center. All-cause death, stroke, and myocardial infarction event rates were analyzed using log-rank analysis.

      Results

      Among the 996 patients treated with carotid endarterectomy (n = 787) or carotid artery stenting (n = 209), the 30-day, 1-year, 5-year, and 10-year survival rates for carotid endarterectomy patients were 99.1%, 95.3%, 77.9%, and 54.8%; carotid artery stenting rates were 99.5%, 96.2%, 67.8%, and 40.2%, respectively (P = .005, at 10 years). There was no significant difference in early stroke rates or myocardial infarction rates between the groups. Subgroup analysis comparing symptomatic status demonstrated no statistically significant differences in overall survival, stroke, or myocardial infarction rates at 10 years. In addition to reduced long-term overall survival, carotid artery stenting patients had a higher long-term restenosis rate as compared to carotid endarterectomy (6.3% vs 2.8%, P < .0001) and reduced restenosis-free survival (P = .01).

      Conclusions

      Early death, stroke, and myocardial infarction rates are comparable after carotid endarterectomy and carotid artery stenting. Carotid artery stenting is an effective means of preventing stroke among patients with carotid artery stenosis. Symptomatic status does not seem to affect rates of stroke, myocardial infarction, or death. Carotid endarterectomy continues to be the preferred long-term solution for extracranial carotid artery occlusive disease as it is associated with better long-term survival and lower restenosis rates.

      Introduction

      Stroke is the fourth leading cause of death for Americans, and over 88% of these strokes are ischemic. Almost one-quarter of ischemic strokes can be attributed to atherosclerotic narrowing of the carotid arteries.
      • Litsky J
      • Stilp E
      • Njoh R
      • Mena-Hurtado C
      Management of symptomatic carotid disease in 2014.
      Carotid endarterectomy (CEA) has long been considered the gold standard treatment for carotid stenosis.
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      • Barr HW
      • Clagett GP
      • Barnes RW
      • Wallace MC
      • et al.
      The North American Symptomatic Carotid Endarterectomy Trial: surgical results in 1415 patients.
      Large landmark trials, including the North American Symptomatic Carotid Endarterectomy Trial, demonstrated a reduction in the risk of stroke for patients undergoing CEA when compared to best medical therapy, particularly in symptomatic patients with severe stenosis.
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      • et al.
      NASCET Collaborators
      Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis.
      More recently, carotid artery stenting (CAS) has emerged as a less invasive alternative to CEA. A landmark study, the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), found that CAS and CEA had similar results when comparing the primary outcome of any periprocedural stroke, myocardial infarction (MI), death, or postprocedure ipsilateral stroke.
      • Brott TG
      • 2nd HobsonRW
      • Howard G
      • Roubin GS
      • Clark WM
      • Brooks W
      • et al.
      Stenting versus endarterectomy for treatment of carotid-artery stenosis.
      CREST also found that CAS was associated with higher rates of perioperative stroke, whereas CEA was associated with a greater risk of perioperative MI.
      CREST provided a great deal of information regarding the safety and efficacy of CAS when compared to CEA but had a large number of exclusion criteria and restrictions related to study inclusion.
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      Design of the Carotid Revascularization Endarterectomy vs.
      The goal of our study was to analyze the long-term outcomes of these 2 therapies in a real-world experience at an urban academic medical center.

      Methods

      Approval from the Northwestern University Institutional Review Board was obtained before conducting this single-center retrospective chart review of patients who underwent either CEA or CAS between January 2001 and December 2011. Dates were selected to include a large cohort of patients while also allowing the possibility for several years of follow-up after the last procedure to better evaluate long-term outcomes. Patients were identified via querying the Northwestern Medicine Enterprise Data Warehouse, a storehouse of patient data. Informed consent was waived for this study. All operations and procedures were performed at Northwestern Memorial Hospital in Chicago by board-certified vascular surgeons.
      One-thousand-four patients were identified as having undergone CEA or CAS between January 2001 and December 2011. Eight patients were excluded from analysis as they underwent both CEA and CAS on contralateral sides, leading to a final cohort of 996 patients. Patients undergoing bilateral CEA or bilateral CAS were included in the analysis for their respective procedure groups. Patients who underwent initial treatment with CEA or CAS at our institution who subsequently developed restenosis requiring CAS were included in their initial procedural group. Information including patient demographics, comorbid conditions, procedure dates, symptomatic status, degree of stenosis, procedure details, procedure complications, medications, follow-up dates, stroke rates (based on clinical diagnosis of acute focal neurologic signs lasting >24 hours), MI rates, and death were obtained retrospectively from patient records and the Social Security Death Index.
      Patients were categorized based on procedure type, and the information gathered was compared between the groups. Additionally, subgroup analysis based on symptomatic status was undertaken. Symptomatic patients were defined as those who had a transient ischemic attack (TIA), amaurosis fugax, or minor nondisabling stroke 180 days or fewer before operative intervention, as in CREST.
      • Brott TG
      • 2nd HobsonRW
      • Howard G
      • Roubin GS
      • Clark WM
      • Brooks W
      • et al.
      Stenting versus endarterectomy for treatment of carotid-artery stenosis.
      Categorical variables were summarized by frequencies and percentages, and differences between procedure type groups were assessed via Fisher's exact test. Continuous variables were summarized by means, standard deviations, medians, and ranges, and differences were evaluated via the Wilcoxon rank-sum test. Overall survival, stroke-free survival, restenosis-free survival, and MI-free survival rates were estimated via Kaplan-Meier analysis. Differences were analyzed via the log-rank method. Analyses were conducted in SAS v9.4 (SAS Institute Inc., Cary, NC).

      Results

      Cohort

      Nine-hundred-ninety-six patients fulfilled inclusion criteria and were included in the study. Seven-hundred-eighty-seven underwent CEA, while 209 underwent CAS. Patient demographics are shown in Table 1. Briefly, mean age (standard deviation) was 71.0 (9.2) years for patients undergoing CAS and 69.8 (9.2) years for CEA. Among patients undergoing CAS, 60.3% were male, while 63.7% of patients undergoing CEA were male. Among the procedure groups, similar rates of smoking history (71.2% CAS, 68.2% CEA), diabetes (27.3% CAS, 28.0% CEA), prior stroke (28.7% CAS, 34.2% CEA), and prior TIA (23.9% CAS, 18.7% CEA) were present. Patients undergoing CEA in this cohort were more likely to have a history of hypertension (65.1% CAS, 75.7% CEA; P = .003), while those undergoing CAS were more likely to have a history of peripheral vascular disease (29.7% CAS, 22.5% CEA; P = .04) and a history of heart disease (44.5% CAS, 36.6% CEA; P = .04).
      Table 1Patient characteristics.
      All patientsCAS (n = 209)CEA (n = 787)P-value
      PatientsN
      Age at procedure, yrMean ± SD71.0 ± 9.269.8 ± 9.2.056
      Median (range)71 (43–90)70 (36–97)
      Follow-up time, dMean ± SD1,233 ± 1,1601,615 ± 1,414.02
      Median (range)902 (0–4,122)1,435 (0–5,593)
      Time from procedure to stroke, dMean ± SD1,056 ± 9561,421 ± 1,230.0004
      Median (range)953 (1–2,729)1,326 (0.6–4,627)
      Time from procedure to MI, dMean ± SD641 ± 8161332 ± 1063<.0001
      Median (range)390.5 (1–2,595)1,229.5 (1–4,367)
      Time from procedure to death (based on Social Security Death Index), dMean ± SD1,346 ± 8251,644 ± 1,119.30
      Median (range)1,108 (2–3,455)1,541 (2–5143)
      Percent stenosisMean ± SD82.2 ± 9.676.5 ± 12.4<.0001
      Median (range)80 (40–99)80 (38–100)
      White raceFrequency (%)177 (84.7%)615 (78.1%).04
      MaleFrequency (%)126 (60.3%)501 (63.7%).38
      History of smokingFrequency (%)148 (71.2%)484 (68.2%).44
      History of obesityFrequency (%)12 (5.7%)42 (5.3%).86
      History of diabetesFrequency (%)57 (27.3%)220 (28.0%).93
      History of hypertensionFrequency (%)136 (65.1%)596 (75.7%).003
      History of peripheral vascular diseaseFrequency (%)62 (29.7%)177 (22.5%).04
      History of heart diseaseFrequency (%)93 (44.5%)288 (36.6%).04
      History of strokeFrequency (%)60 (28.7%)269 (34.2%).14
      History of TIA/ amaurosis fugaxFrequency (%)50 (23.9%)147 (18.7%).10
      Symptomatic prior to surgeryFrequency (%)78 (37.5%)348 (44.4%).08
      Contralateral occlusionFrequency (%)26 (12.9%)52 (6.7%).01
      Contralateral stenosisFrequency (%)45 (22.3%)166 (21.3%)
      No contralateral occlusion or stenosisFrequency (%)131 (64.9%)562 (72.1%)
      Postprocedural complicationFrequency (%)51 (24.4%)209 (26.6%).60
      Postprocedural cranial nerve injuryFrequency (%)0 (0.0%)24 (3.1%)<.0001
      Postprocedural hypotensionFrequency (%)27 (12.9%)22 (2.8%)<.0001
      Postprocedural bradycardiaFrequency (%)20 (9.6%)4 (0.5%)<.0001
      Postprocedural hematomaFrequency (%)8 (3.8%)34 (4.3%).85
      Antihypertensive medicinesFrequency (%)180 (86.5%)651 (83.4%).29
      Anticoagulation medicinesFrequency (%)25 (12.0%)108 (13.9%).57
      Lipid-lowering medicinesFrequency (%)164 (78.9%)593 (75.9%).41
      Antiplatelet medicinesFrequency (%)202 (97.1%)681 (87.2%)<.0001
      General anesthesiaFrequency (%)9 (4.4%)760 (96.6%)<.0001
      Local anesthesiaFrequency (%)197 (95.6%)27 (3.4%)
      Restenosis after initial procedure at our facilityFrequency (%)13 (6.3%)22 (2.9%)<.0001
      Restenosis after prior procedure at outside hospital, subsequently treated at our facilityFrequency (%)34 (16.5%)11 (1.4%)
      Restenosis from prior procedure followed by restenosis after procedure at our facilityFrequency (%)3 (1.5%)0 (0.0%)
      For CEA: Shunt usageFrequency (%)0 (0.0%)181 (23.1%)
      For CAS: Embolic protectionFrequency (%)191 (93.2%)0 (0.0%)
      TIA = Transient ischemic attack

      Procedure

      Similar rates of symptomatic status were present among patients undergoing both CEA and CAS. Patients undergoing CAS had a higher mean percent of stenosis prior to operative intervention (82.2% CAS, 76.5% CEA; P < .0001) and were almost twice as likely to have contralateral arterial occlusion (12.9% CAS, 6.7% CEA; P = .01). Among patients undergoing CAS, the majority of cases were performed under local anesthesia, while the opposite was true for patients undergoing CEA. Embolic protection devices were used in 93.2% of CAS cases, and shunts were used in 23.1% of CEA cases. Sixty-one patients (7.7%) undergoing CEA had bilateral CEA performed over the course of the study. Ten (4.8%) patients undergoing CAS had bilateral CAS performed over the course of the study. Eight patients underwent CEA and CAS on contralateral sides and were excluded from further data analysis.

      Postprocedural

      Similar overall rates of postprocedural complications existed among patients undergoing CAS and CEA (24.4% and 26.6%, respectively), but the groups differed in the type of complications. Among CAS patients, the most common postprocedural complications included hypotension (12.9% CAS, 2.8% CEA; P < .0001) and bradycardia (9.6% CAS, 0.5% CEA; P < .0001). The most common postprocedural complication among patients undergoing CEA was hematoma (3.8% CAS, 4.3% CEA; P = .85), though rates of postprocedural hematomas were similar between CAS and CEA patients. There were no significant differences between the 2 groups in rates of antihypertensive, anticoagulation, or lipid-lowering therapy upon postprocedural discharge from the hospital. Patients who underwent CAS were more likely to have been placed on dual antiplatelet therapy than those treated with CEA (97.1% CAS, 87.2% CEA; P < .0001).

      MI, Stroke, and Death Rates

      Survival curves for death, MI, and stroke are shown in Figs 1, 2, and 3 with 30-day, 1-year, 5-year, and 10-year rates included. Cumulative incidence rates for stroke and MI are shown in Tables 2 and 3. At 30 days, our study found no differences between procedure groups in stroke-free (98.1% CAS, 98.3% CEA) and MI-free rates (98.1% CAS, 98.7% CEA). Additionally, no differences were noted in cumulative incidence rates of stroke (1.9% CAS, 1.8% CEA) or MI (CAS 2.4%, CEA 1.6%) at 30 days. Of note, CAS and CEA also demonstrated similar durability and efficacy in preventing ischemic stroke long term, with no statistically significant difference in stroke-free survival or cumulative stroke rate present over the course of 10 years of follow-up (83.7% stroke-free survival for CAS, 82.9% stroke-free survival for CEA; 11.4% stroke rate for CAS, 13.2% stroke rate for CEA). Similarly, no significant differences were found in the rates of MI or MI-free survival between CAS and CEA at 10 years (88.9% CAS MI-free survival, 82.8% CEA MI-free survival; 9.0% MI rate for CAS, 13.3% MI rate for CEA). The 30-day, 1-year, 5-year, and 10-year overall survival rates for patients following CEA were 99.1% (95% confidence interval [CI] 98.0–99.6), 95.3% (95% CI 93.4–96.7), 77.9% (95% CI 74.2–81.1), and 54.8% (95% CI 49.4–59.8), respectively, as compared to CAS rates: 99.5%; 96.2%; 67.8%; and 40.2% respectively (P = .005 at 10 years).
      Fig 1
      Fig. 1Overall survival curve for CAS and CEA.
      Fig 2
      Fig. 2Stroke-free survival curve for CAS and CEA.
      Fig 3
      Fig. 3MI-free survival curve for CAS and CEA.
      Table 2Cumulative incidence rates of stroke.
      Cumulative incidence rate of stroke (%)30 d (95% CI)1 yr (95% CI)5 yr (95% CI)10 yr (95% CI)P-value
      CAS1.9 (0.6–4.6)3.6 (1.6–7.0)6.5 (3.4–10.9)11.4 (6.2–18.2).98
      N = 182N = 140N = 63N = 8
      CEA1.8 (1.1–3.0)2.9 (1.8–4.3)7.6 (5.7–10.0)13.2 (10.0–16.9)
      N = 640N = 540N = 311N = 81
      Table 3Cumulative incidence rates of MI.
      Cumulative incidence rate of MI (%)30 d (95% CI)1 yr (95% CI)5 yr (95% CI)10 yr (95% CI)P-value
      CAS2.4 (0.9–5.2)3.6 (1.6–6.9)7.3 (3.9–12.1)9.0 (4.7–15.2).54
      N = 180N = 140N = 64N = 9
      CEA1.6 (0.9–2.6)2.89 (1.85–4.31)7.9 (6.0–10.3)13.3 (10.2–16.8)
      N = 642N = 536N = 308N = 82

      Restenosis

      Restenosis was identified via chart review of carotid duplex ultrasonography performed at the Northwestern Medicine Vascular Laboratory, demonstrating >70% stenosis of the carotid arteries. Surveillance was conducted at the provider's discretion. Restenosis following an initial procedure at our institution more commonly occurred following CAS than CEA (6.3% CAS, 2.9% CEA; P < .0001). A survival curve for restenosis for patients undergoing a first operative intervention for carotid stenosis is shown in Fig 4. Notably, patients undergoing CAS were more likely to experience restenosis than those undergoing CEA. Early restenosis-free survival rates were similar at both 30 days (100.0% CAS, 99.8% CEA) and 1 year (97.5% CAS, 98.3% CEA) but diverged significantly by 5 years (85.8% CAS, 96.1% CEA). Additionally, patients who had previously undergone treatment for carotid artery stenosis at an outside hospital and subsequently developed restenosis were more likely to be treated with CAS than with CEA (16.5% CAS, 1.4% CEA; P < .0001). Of the 37 patients who had restenosis after an outside hospital intervention and were subsequently treated with CAS at our hospital, 3 developed restenosis. Of the 11 patients who had restenosis after an outside hospital intervention and were subsequently treated with CEA at our hospital, none developed restenosis.
      Fig 4
      Fig. 4Restenosis-free survival curve for CAS and CEA.

      Subgroup Analysis

      Symptomatic status was examined as a possible cause of increased rates of stroke, death, or MI between the procedural groups. No statistically significant differences were found in terms of MI, stroke, or overall survival between symptomatic and asymptomatic CEA patients or CAS patients.

      Discussion

      As life expectancy increases, data regarding the durability and effectiveness of CEA and CAS at advanced time points will be crucial in determining which procedure to recommend to patients as treatment for carotid artery disease. The most striking data from our patient population is the difference observed in overall survival between procedure groups. There is insufficient research available comparing long-term survival following CAS versus CEA. A large number of studies that offer long-term follow-up after these procedures focus on a primary endpoint of periprocedural outcomes plus long-term ipsilateral stroke but do not emphasize rates of overall survival or all-cause mortality.
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      Long-term outcomes of carotid artery stenting in clinical practice.
      • Brott TG
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      • Mackey A
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      Long-term results of stenting versus endarterectomy for carotid-artery stenosis.
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      • de Borst GJ
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      Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial.
      Long-term stroke prevention is an important aspect in deciding between CEA and CAS, but it is irrelevant if patients do not survive long enough to derive a benefit from their procedure.
      Among our patient population, those undergoing CAS are clearly at higher risk of adverse outcomes, likely as a result of a combination of factors including preexisting comorbidities. These patients were noted to have higher rates of both peripheral vascular disease and coronary artery disease (CAD), significant contributors to overall morbidity and mortality. Additionally, they presented with higher rates of contralateral carotid occlusion, further evidence of a higher burden of vascular disease. It has been shown in other surgical fields that patients with CAD undergoing surgery are at a 5-fold increased risk of postoperative mortality, even when similar rates of major adverse cardiac events are present, when compared to control groups without CAD.
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      Coronary stenosis also places patients at significant risk for adverse vascular outcomes following CEA, even beyond the periprocedural period.
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      Selection bias certainly played some role in the long-term survival differences observed in our cohort. Many CAS procedures were likely performed due to a physician's determination that the patient would be unable to tolerate the rigors of general anesthesia and surgical endarterectomy. Of particular note, however, is that even among this cohort, CAS provided patients with the same long-term protection from stroke. In this sense, our findings parallel the long-term results of CREST, which noted no difference in long-term ipsilateral stroke risk between the procedural groups (6.9% CAS, 5.6% CEA).
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      Long-term results of stenting versus endarterectomy for carotid-artery stenosis.
      Additionally, CAS patients did not have increased rates of MI when compared to CEA. A recent retrospective study comparing long-term CEA and CAS results found no differences in rates of stroke, MI, or death over a median follow-up time of 5.4 years.
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      The differences observed in long-term death rates between the previously mentioned study and our own highlight the need for continued research on real-world outcomes. Though multiple studies have shown the equivalency of CEA and CAS in select populations, it is clear that real-world practice has an inherent selection bias that detracts from the generalizability of these studies in the long term. Similarly, it highlights the significant impact that differences in surgical populations can have on procedural outcomes.
      The primary composite endpoint of CREST includes any periprocedural stroke, MI, or death in addition to any subsequent ipsilateral stroke. No difference was found between CEA and CAS when extending the study to include 10 years of follow-up (11.8% CAS, 9.9% CEA).
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      Long-term results of stenting versus endarterectomy for carotid-artery stenosis.
      Among our patient population, a rate of 14.3% was found for CAS and a rate of 15.7% for CEA, primarily driven by the rates of stroke present in our cohort at 10 years. The rate of stroke observed in our study is similar to those observed at 10 years of follow-up in the ECST trial.
      Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST).
      Of particular note, due to the retrospective nature of our study, it was often not possible to localize the side of a stroke. Our study thus reports a rate of overall stroke rather than ipsilateral stroke, explaining the elevated rate relative to CREST. Although our study may report higher rates of CREST's primary endpoint than CREST did, it is notable that our rates between CEA and CAS are almost identical, supporting the durability of CAS when compared to CEA in preventing stroke.
      Periprocedural outcomes were relatively similar between our study population and that of the CREST trial, including death rates (0.7% CAS, 0.3% CEA), MI rates (1.1% CAS, 2.3% CEA), and stroke rates (4.1% CAS, 2.3% CEA), with some notable differences.
      • Brott TG
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      • Howard G
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      Stenting versus endarterectomy for treatment of carotid-artery stenosis.
      In our study, there was no statistically significant difference in the rates of stroke and MI between the 2 procedural groups, while CREST did find these differences to be significant in the periprocedural period. Patients undergoing CAS in our study were more likely to have a history of both peripheral vascular disease and CAD compared to those undergoing CEA, perhaps contributing to the narrowed gap in MI rates between the procedural groups. Additionally, it is possible that the higher prevalence of hypertension present in those undergoing CEA in our study increased the risk for stroke perioperatively and contributed to the narrowed risk of periprocedural stroke. Our sample size is also smaller than that of CREST (996 patients versus 2,502), and it is possible that such differences may also become more evident as sample size increases.
      Our data show a clear divergence in restenosis-free survival between procedural groups that is apparent by 3 years of follow-up. A recent propensity-matched retrospective chart review comparing CAS and CEA found higher rates of restenosis among patients undergoing CAS when compared to CEA (5.3% vs 2.6%, respectively) with mean follow-up of 49.1 months.
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      Other studies have shown increased rates of restenosis following CAS when compared to CEA. EVA-3S, for example, found that short-term restenosis or occlusion occurred roughly 2.5 times more frequently after CAS than after CEA.
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      A recent meta-analysis examined the impact of restenosis following both CAS and CEA on stroke risk. Among CAS patients with asymptomatic restenosis >70%, only 0.8% had an ipsilateral stroke.
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      As a means of stroke prevention, our study supports the use of CAS when treating patients with a history of restenosis, as no differences were found in stroke rates between procedural groups and CAS offers a means of treatment without the inherent surgical risk of cranial nerve injury.
      Periprocedural outcomes for CAS following CREST were noted to be superior to many found in prior randomized studies. Differences were noted between rates of stroke or death among symptomatic patients (6.0% CREST, 6.8% SPACE, 9.6% EVA-3S, and 7.4% ICSS).
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      Our 30-day results among symptomatic CAS patients mirror the lower rates found with CREST (1.37% stroke risk, 0.0% death rate). Four-year death rates for CAS and CEA in CREST were 11.3% and 12.6%, respectively. Our 3-year and 5-year rates of death were 12.8% and 22.1%, respectively, among patients undergoing CEA, similar to the available 4-year CREST rate. Among CAS patients, however, 3-year and 5-year rates of death were 21.1% and 32.2%, respectively. The higher rates of death evident among patients undergoing CAS are likely attributed to the higher burden of vascular and other systemic diseases present in this patient population, as discussed earlier.
      CEA has shown an established benefit in stroke prevention in both symptomatic and asymptomatic patients when compared to best medical therapy (BMT), and CAS has been found to be noninferior to CEA.
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      • Peto C
      • Peto R
      • Potter J
      • et al.
      Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial.
      When considering asymptomatic carotid stenosis, however, some argue that BMT has changed to such a degree that prior randomized control trial results are no longer applicable to certain patients.
      • Spence JD
      • Naylor AR
      Endarterectomy, stenting, or neither for asymptomatic carotid-artery stenosis.
      The Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis (CREST-2) trial aims to answer how best to treat high-grade asymptomatic carotid stenosis.
      • Howard VJ
      • Meschia JF
      • Lal BK
      • Turan TN
      • Roubin GS
      • Brown Jr, RD
      • et al.
      Carotid revascularization and medical management for asymptomatic carotid stenosis: Protocol of the CREST-2 clinical trials.
      While those in favor of BMT alone argue that annual stroke risks on current BMT mirror those found in CREST and ACT I, it is impossible to determine whether BMT alone is truly superior to CEA or CAS plus BMT without adequately powered randomized data.
      • Spence JD
      • Naylor AR
      Endarterectomy, stenting, or neither for asymptomatic carotid-artery stenosis.
      • Heck DV
      • Roubin GS
      • Rosenfield KG
      • Gray WA
      • White CJ
      • Jovin TG
      • et al.
      Asymptomatic carotid stenosis: Medicine alone or combined with carotid revascularization.
      The primary limitation of our study is its retrospective nature. It is possible our data represent an underestimation of the true long-term rates of stroke and MI in this cohort. If patients sought care for a stroke or MI at an outside hospital, their experience would not have been captured within our chart review. Additionally, a number of patients were lost to follow-up, making it impossible to fully document their clinical course.

      Conclusions

      Both CAS and CEA offer durable means of stroke prevention as treatment modalities for carotid artery stenosis. We did not find significant differences in the rates of periprocedural stroke, death, or MI between patients undergoing CEA and CAS. Within our cohort, CAS was associated with a statistically significant decreased rate of survival at 10 years, likely due to an overall higher vascular disease burden present in this population. CAS was also more likely to result in carotid artery restenosis than CEA. Among our cohort, symptomatic status did not affect rates of stroke, MI, or death. CEA continues to remain the gold standard for treatment of carotid disease, given its increased overall survival and decreased rate of restenosis when compared to CAS.

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