***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: OBJECTIVES This study sought to compare the efficacy of two different cerebral protection systems for the prevention of embolization during carotid artery stenting ( CAS ) using a transcranial Doppler ( TCD ) monitoring with the detection of microembolic signals ( MES ) . BACKGROUND Despite the introduction of cerebral protection systems , neurologic complications during CAS can not completely be prevented . Transcranial Doppler and detection of MES may aid in assessing the efficacy of different neuroprotection systems . METHODS A total of 42 patients with internal carotid artery stenoses were treated by CAS using either a filter ( E.P.I. FilterWire , Boston Scientific Corp. , Santa Clara , California ) ( n = 21 ) or a proximal endovascular clamping device ( MO.MA system , Invatec s.r.l . , Roncadelle , Italy ) ( n = 21 ) . Microembolic signal counts were compared during five phases : placement of the protection device , passage of the stenosis , stent deployment , balloon dilation , and retrieval of the protection device . RESULTS There were no significant differences in clinical or angiographic outcomes between the two groups . Compared to the filter device , the MO.MA system significantly reduced MES counts during the procedural phases of wire passage of the stenosis , stent deployment , balloon dilation , and in total ( MES counts for the filter device were 25 + /- 22 , 73 + /- 49 , 70 + /- 31 , and 196 + /- 84 during the three phases and in total , MES counts for the MO.MA system were 1.8 + /- 3.2 , 11 + /- 19 , 12 + /- 21 , and 57 + /- 41 , respectively ; p < 0.0001 ) . CONCLUSIONS In comparison to a filter device the MO.MA system led to significantly lower MES counts during CAS . The detection of MES by TCD may facilitate the evaluation and comparison of different neuroprotection systems OBJECTIVE Anatomic suitability for carotid artery stenting ( CAS ) is determined by arteriography , but this has a discrete stroke risk . We evaluated the use of multidetector CT angiography with three-dimensional reconstruction ( 3D-CTA ) as a noninvasive screening tool for prospect i ve CAS patients . METHODS Between 2003 and 2006 , 90 CAS procedures were performed by vascular surgeons at our institution . At the discretion of the operating surgeon , 59 of the potential c and i date s for CAS underwent screening 3D-CTA of the aortic arch and carotid arteries . Results were used in patient selection and then analyzed retrospectively to determine clinical utility . RESULTS Analysis of 3D-CTA data by the operating surgeon allowed stratification of patients into four groups : ( 1 ) appropriate for CAS via femoral approach ( n = 37 , 63 % ) ; ( 2 ) appropriate for CAS with transcervical access due to adverse arch anatomy ( n = 2 , 3 % ) ; ( 3 ) borderline anatomy for CAS ( n = 5 , 9 % ) ; or ( 4 ) not appropriate anatomy for CAS ( n = 15 , 25 % ) . Group 1 had 100 % technical success with one minor stroke . Group 2 had successful transcervical CAS without stroke . Group 3 patients underwent arteriography but CAS was aborted in four out of five cases for the same reason that had been identified by 3D-CTA ( internal carotid artery [ ICA ] tortuosity n = 2 , ICA string sign with distal disease n = 2 ) . The one failure in group 3 was the result of a previously placed common carotid stent extending into an already unfavorable aortic arch . Group 4 patients underwent endarterectomy ( n = 7 ) or continued medical management ( n = 8) instead of CAS ( without arteriography ) because of the following reasons , cited alone or in combination : common carotid t and em stenosis n = 5 , difficult arch anatomy n = 2 , ICA tortuosity n = 2 , extreme lesion calcification or length n = 4 , ICA string sign or occlusion n = 3 , concomitant intracranial disease n = 2 , and stenosis overestimated by duplex n = 3 . The overall 30-day stroke rate , on an intention to treat basis , for patients that underwent preprocedural 3D-CTA was 2.3 % ( one major [ NIH stroke scale > 3 ] and one minor stroke ) . CONCLUSIONS In our initial experience , 3D-CTA reconstruction of the aortic arch and carotid arteries significantly influenced the plan for CAS in 37 % of patients . Patients with clear anatomic contraindications to CAS can be excluded without the risks of arteriography . 3D-CTA further facilitates the CAS procedure by anticipating potential procedural . The cost-effectiveness and potential impact of this imaging modality on CAS outcomes deserve further study Rationale Carotid endarterectomy ( CEA ) and medical therapy were shown superior to medical therapy alone for symptomatic ( ge;50 % ) and asymptomatic ( ≥60 % ) stenosis .  Carotid angioplasty stenting ( CAS ) offers a less invasive alternative . Establishing safety , efficacy , and durability of CAS requires rigorous comparison with CEA in symptomatic and asymptomatic patients . Aims The objective is to compare the efficacy of CAS versus CEA in patients with symptomatic ( ≥50 % ) or asymptomatic ( ≥60 % ) extracranial carotid stenosis . Design The Carotid Revascularization Endarterectomy vs. Stenting Trial ( CREST ) is a prospect i ve , r and omized , parallel , two-arm , multi-center trial with blinded endpoint adjudication . Primary endpoints are analyzed using st and ard time-to-event statistical modeling with adjustment for major baseline covariates . Primary analysis is on an intent-to-treat basis . Study Outcomes The primary outcome is the occurrence of any stroke , myocardial infa rct ion , or death during a 30-day peri-procedural period , and ipsilateral stroke during follow-up of up to four years . Secondary outcomes include restenosis and health-related quality of life This prospect i ve cohort study was taken to determine whether transcervical carotid artery stenting ( CAS ) with internal carotid artery ( ICA ) flow reversal is associated with a lower incidence of embolization and femoral access complication when compared with protected , transfemoral CAS in selected , high-risk patients . From 2002 to October 2004 , the authors performed 55 carotid stentings and angioplasties .  Among the 24 cases via transfemoral approach , 1 developed transient ischemic attack ( TIA ) , 1 stroke , 1 asystolic cardiac arrest , 2 groin hematoma , 2 technical failure , and 1 restenosis . Among the 31 cases via transcervical approach , 2 patients developed TIAs , 4 bradycardia , 2 cervical hematoma , and 3 technical failures leading to open conversion and carotid endarterectomy . Transcervical CAS with ICA flow reversal eliminates the risk of aortic arch emboli , provides cerebral protection during predeployment manipulation across the carotid lesion , negates preprocedure mapping of the aortic arch configuration , and surpasses difficult aortic arch or transfemoral access Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Background —The distal-balloon protection system is being evaluated for its efficacy in preventing embolic neurological events during carotid stenting ( CAS ) . We sought to determine the effect of this system on the frequency of Doppler-detected microembolic signals ( MES ) during CAS . Methods and Results —Using transcranial Doppler , we compared the frequency of MES during CAS in 2 groups : 39 patients without distal protection and 37 who used the distal-balloon protection system ( GuardWire ) . There were no significant differences in the clinical or angiographic characteristics between the 2 groups . Three phases with increased MES counts were identified during unprotected CAS ; these were stent deployment , predilation , and postdilation ( 75±57 , 32±36 , and 27±25 METS , respectively ) . The distal-balloon protection significantly reduced the frequency of MES during CAS ( MES counts : 164±108 in the control versus 68±83 in the protection group;P = 0.002 ) , particularly during these 3 phases . MES in the protection group were detected predominantly during sheath placement , guidewire manipulation , and distal-balloon deflation . Conclusion —Three phases with increased MES counts were identified during unprotected CAS ( eg , stent deployment , predilation , and postdilation ) . The distal-balloon protection system significantly reduced the frequency of MES during CAS , particularly during these 3 phases Purpose : To report early clinical outcomes with a novel double-layer stent for the internal carotid artery ( ICA ) and the in vitro investigation of the stent ’s mechanical properties . Methods : A prospect i ve single-center study enrolled 30 consecutive patients ( mean age 73.1±6.3 years ; 21 men ) with symptomatic ( n=25 ) or high- grade ( n=5 ) ICA stenosis treated with the new double-layer carotid CGUARD Embolic Prevention System ( EPS ) stent  , which has an inner open-cell nitinol design with an outer closed-cell polyethylene terephthalate layer . The average stenosis of the treated arteries was 84.1%±7.9 % with a mean lesion length of 16.6±2.1 mm . In the laboratory , 8 × 40-mm stents where tested in vitro with respect to their radial force during expansion , the bending stiffness of the stent system and the exp and ed stent , as well as the collapse pressure in a thin and flexible sheath . The wall adaptation was assessed using fluoroscopy after stent release in step and curved vessel models . Results : The stent was successfully implanted in all patients . No peri- or postprocedural complications occurred ; no minor or major stroke was observed in the 6-month follow-up . The bending stiffness of the exp and ed stent was 63.1 N·mm2 and ( not unexpectedly ) was clearly lower than that of the stent system ( 601.5 N·mm2 ) . The normalized radial force during expansion of the stent to 7.0 mm , consistent with in vivo sizing , was relatively high ( 0.056 N/mm ) , which correlates well with the collapse pressure of 0.17 bars . Vessel wall adaptation was harmonic and caused no straightening of the vessel after clinical application . Conclusion : Because of its structure , the novel CGUARD EPS stent is characterized by a high flexibility combined with a high radial force and very good plaque coverage . These first clinical results demonstrate a very safe implantation behavior without any stroke up to 6 months after the procedure OBJECTIVES This study sought to r and omly compare cerebral protection with ANGIOGUARD ( Cordis Corporation , Bridgewater , New Jersey ) with Mo . Ma ( Invatec/Medtronic Vascular Inc , Santa Rosa , California ) during  carotid artery stenting ( CAS ) , using diffusion-weighted magnetic resonance imaging ( DW-MRI ) to detect new ischemic cerebral lesions . The number , size , and location of lesions were analyzed . BACKGROUND The choice of the type of cerebral protection during CAS is controversial . METHODS From July 2008 to July 2011 , 60 patients undergoing CAS were r and omized to ANGIOGUARD or Mo . Ma , distributed by chance , 30 patients for each group . All patients underwent DW-MRI  before and after CAS . An independent neuroradiologist blinded to the cerebral protection used analyzed the images . Univariate and multivariate logistic models were fitted to analyze new ischemic lesions . Alternatively , a propensity score approach was used to reduce the bias due to differences between the groups . For the number of lesions , we used Poisson regression models . RESULTS New ischemic lesions seen on DW-MRI were present in 63.3 % of the ANGIOGUARD group versus 66.7 % of the Mo . Ma cohort ( p = 0.787 ) . The number of ischemic cerebral lesions per patient , when present , was significantly lower in the Mo . Ma group ( a median of 6 lesions per patient vs. a median of 10 in the ANGIOGUARD , p < 0.001 ) . Most lesions were small ( < 0.5 mm ) and localized in the ipsilateral territory . One patient in the ANGIOGUARD group had a minor stroke during CAS ( 1.66 % ) . CONCLUSIONS New ischemic lesions seen on DW-MRI were present in both groups in > 60 % , but the number of lesions per patient was greater in the ANGIOGUARD group . No death or disabling stroke occurred during at least 1 year of follow-up in both cohorts BACKGROUND Transfemoral carotid artery stenting ( CAS ) has been associated with a high incidence of embolic phenomena and silent brain infa rct ion . The goal of this study was to compare the incidence of new ischemic cerebral lesions on diffusion-perfusion magnetic resonance imaging ( MRI ) sequences after transcervical CAS performed with carotid flow reversal vs 
    Output:
    
Conclusion : TCA is associated with a significantly lower risk for periprocedural stroke and DW-MRI ischemic lesions compared with TFA .
Other periprocedural outcomes were similar between the groups