***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    Input: Although the incidence of carotid atheromatous disease is presumably equal between the right and left carotid arteries , right and left carotid endarterectomies ( CEs ) may not be performed with equal frequency on the two sides . This study sought to examine whether right and left CEs are performed with equal frequency and whether there are any differences in outcome between these groups . Detailed chart review was performed on all  CEs performed from 1979 through 1998 at our institution , and those lacking side data were excluded . Data were collected on the side of the procedure , demographics , comorbid conditions , details of the procedure , hospital stay , and major complications . The surgeons performing CE were surveyed about their practice of considering side factors . CE was performed on the left in 1190 ( 52 % ) of 2305 procedures ; 1115 ( 48 % ) of the procedures were right CEs . This difference is statistically significant ( P = 0.014 ) . No significant differences in demographics , comorbidity , presence of symptoms before surgery , length of stay , or postoperative morbidity or mortality between the left and right groups were found . A majority of the surgeons surveyed indicated they do consider the relationship of side of the carotid disease to the patient 's dominant side . The significant difference in the performance of left CE  more often than right has not been previously reported . This may reflect willingness by surgeons to intervene more frequently in carotid disease on the side supplying the dominant hemisphere . A prospect i ve CE outcome study that identifies the side of CE and the patient 's dominant side is needed for further exploration of this issue BACKGROUND The objective of this study was to assess whether carotid endarterectomy is an appropriate treatment for patients with recent cerebrovascular events in the territory supplied by a moderately stenosed ( 30 - 69 % ) internal carotid artery . Results have previously been reported for severe ( 70 - 99 % ) and mild ( 0 - 29 % ) stenosis . METHODS A multicentre r and omised controlled trial recruited 1599 patients with moderate stenosis treated in 97 hospitals from 15 countries . 60 % of patients were allocated to receive and 40 % to avoid carotid endarterectomy . The analysis was by intention to treat . FINDINGS Nine patients were omitted from the analysis because no follow-up data were received . Stroke-free life expectancy ( curtailed at 8 years ) was shorter in the surgery patients than in the non-surgery control groups ( patients with 30 - 49 % stenosis , life expectancy = 6.16 years [ controls : 6.63 years ] ; patients with 50 - 69 % stenosis , life expectancy = 5.93 [ 6.14 ] years ) . It remains possible that patients might derive some benefit from surgery in the very long term ; however , our data show that no benefit would be gained over a period of < 4 - 5 years in patients with 50 - 69 % stenosis and < 6 - 7 years in patients with 30 - 49 % stenosis . INTERPRETATION Previous interim results from this study showed that surgery is beneficial in patients with severe stenosis but harmful in those with mild stenosis . With more r and omised patients and longer follow-up , the study now shows that endarterectomy is not indicated for most , possibly all , patients with moderate symptomatic carotid stenosis BACKGROUND AND PURPOSE This study reports the surgical results in those patients who underwent carotid endarterectomy in the North American Symptomatic Carotid Endarterectomy Trial ( NASCET ) . METHODS The rates of perioperative stroke and death at 30 days and the final assessment of stroke severity at 90 days were calculated . Regression modeling was used to identify variables that increased or decreased perioperative risk . Non outcome surgical complications were summarized . The durability of carotid endarterectomy was examined . RESULTS In 1415 patients there were 92 perioperative outcome events , for an overall rate of 6.5 % . At 30 days the results were as follows : death , 1.1 % ; disabling stroke , 1.8 % ; and nondisabling stroke , 3.7 % . At 90 days , because of improvement in the neurological status of patients judged to have been disabled at 30 days , the results were as follows : death , 1.1 % ; disabling stroke , 0.9 % ; and nondisabling stroke , 4.5 % . Thirty events occurred intraoperatively ; 62 were delayed . Most strokes result ed from thromboembolism . Five baseline variables were predictive of increased surgical risk : hemispheric versus retinal transient ischemic attack as the qualifying event , left-sided procedure , contralateral carotid occlusion , ipsilateral ischemic lesion on CT scan , and irregular or ulcerated ipsilateral plaque . History of coronary artery disease with prior cardiac procedure was associated with reduced risk . The risk of perioperative wound complications was 9.3 % , and that of cranial nerve injuries was 8.6 % ; most were of mild severity . At 8 years , the risk of disabling ipsilateral stroke was 5.7 % , and that of any ipsilateral stroke was 17.1 % . CONCLUSIONS The overall rate of perioperative stroke and death was 6.5 % , but the rate of permanently disabling stroke and death was only 2.0 % . Other surgical complications were rarely clinical ly important . Carotid endarterectomy is a durable procedure The Feasibility And Safety Trial for its embolic protection device during transluminal intervention in coronary vessels : a European Registry ( FASTER ) was design ed to demonstrate that ( 1 ) the Proxis embolic protection system can control antero grade flow and reverse blood flow in native coronary arteries and saphenous vein grafts ; and ( 2 ) this system can capture embolic debris . Percutaneous coronary intervention on stenotic coronary lesions revolutionized treatment of coronary disease , but is associated with the risk of major adverse cardiac events . This prospect i ve , nonr and omized , multicenter clinical feasibility and safety study enrolled 40 patients with 51 lesions at 4 centers who underwent treatment of stenotic lesions with proximal emboli protection ( Proxis system ) . Proxis was successfully used 95 % of the time , and embolic debris was qualitatively identified in all cases . Major adverse cardiac events occurred in 2 patients ( 5.0 % ) : 1 late in-stent thrombosis result ing in death and 1 non-Q-wave infa rct ion when a lesion was crossed before deployment of the Proxis system .  Mean vessel occlusion time was 4.3 + /- 2.4 minutes . Native flow reversal was sufficient in 31 patients , with a mean aspirate volume of 11.8 + /- 6.5 ml . When the infusion catheter was used to augment reflow , mean occlusion time was 4.6 minutes . In conclusion , this trial is the first to demonstrate that retro grade blood flow can be achieved during proximal occlusion and that the Proxis system can be used safely during intervention of saphenous vein grafts and native coronary arterial lesions to capture embolic material BACKGROUND The efficacy of  carotid endarterectomy for selected patients has been evaluated with r and omized controlled clinical trials . The generalizability of these studies to average surgical practice remains an important public health concern . OBJECTIVE The objective of the study was to determine the predictors of outcome after carotid endarterectomy on a regional basis . PATIENTS AND METHODS The study was design ed as a retrospective cohort study and included all consecutive patients presented for carotid endarterectomy at the 8 University of Toronto-affiliated hospitals in the period from January 1 , 1994 , to December 31 , 1996 . The main outcome measure was 30-day postoperative stroke or death rate . RESULTS During the study interval , 1280 primary carotid endarterectomies were performed . The overall combined stroke and death rate was 6.3 % for all patients who underwent endarterectomy ( 4.0 % for patients who were asymptomatic ) . The significant predictors of poor outcome were the following : presenting symptoms ( odds ratio , 1.74 ; 95 % confidence interval [ CI ] , 0.96 , 3.12 ) , low surgeon volume ( < 6 cases per year ; odds ratio , 3.98 ; 95 % CI , 1.65 , 9.58 ) , and left-sided surgery ( odds ratio , 1.72 ; 95 % CI , 1.07 , 2.76 ) . CONCLUSION These data suggest that adoption of the recommendations of the symptomatic carotid endarterectomy trials is appropriate . However , endarterectomy for asymptomatic lesions remains of uncertain benefit on a regional basis and must be individualized to the experience of the specific surgeon . The surgeon volume/ outcome relationship that is identified in this study suggests a need for a minimum volume threshold for this procedure BACKGROUND Without strong evidence of benefit , the use of carotid endarterectomy for prophylaxis against stroke rose dramatically until the mid-1980s , then declined . Our investigation sought to determine whether carotid endarterectomy reduces the risk of stroke among patients with a recent adverse cerebrovascular event and ipsilateral carotid stenosis . METHODS We conducted a r and omized trial at 50 clinical centers throughout the United States and Canada , in patients in two predetermined strata based on the severity of carotid stenosis--30 to 69 percent and 70 to 99 percent . We report here the results in the 659 patients in the latter stratum , who had had a hemispheric or retinal transient ischemic attack or a nondisabling stroke within the 120 days before entry and had stenosis of 70 to 99 percent in the symptomatic carotid artery . All patients received optimal medical care , including antiplatelet therapy . Those assigned to surgical treatment underwent carotid endarterectomy performed by neurosurgeons or vascular surgeons . All patients were examined by neurologists 1 , 3 , 6 , 9 , and 12 months after entry and then every 4 months . End points were assessed by blinded , independent case review . No patient was lost to follow-up . RESULTS Life-table estimates of the cumulative risk of any ipsilateral stroke at two years were 26 percent in the 331 medical patients and 9 percent in the 328 surgical patients --an absolute risk reduction ( + /- SE ) 17 + /- 3.5 percent ( P less than 0.001 ) . For a major or fatal ipsilateral stroke , the corresponding estimates were 13.1 percent and 2.5 percent -- an absolute risk reduction of 10.6 + /- 2.6 percent ( P less than 0.001 ) . Carotid endarterectomy was still found to be beneficial when all strokes and deaths were included in the analysis ( P less than 0.001 ) . CONCLUSIONS Carotid endarterectomy is highly beneficial to patients with recent hemispheric and retinal transient ischemic attacks or nondisabling strokes and ipsilateral high- grade stenosis ( 70 to 99 percent ) of the internal carotid artery BACKGROUND Our objective was to assess the risks and benefits of carotid endarterectomy , primarily in terms of stroke prevention , in patients with recently symptomatic carotid stenosis . METHODS This multicentre , r and omised controlled trial enrolled 3024 patients . We enrolled men and women of any age , with some degree of carotid stenosis , who within the previous 6 months had had at least one transient or mild symptomatic ischaemic vascular event in the distribution of one or both carotid arteries . Between 1981 and 1994 , we allocated 1811 ( 60 % ) patients to surgery  and 1213 ( 40 % ) to  control ( surgery to be avoided for as long as possible ) . Follow-up was until the end of 1995 ( mean 6.1 years ) , and the main analyses were by intention to treat . FINDINGS The overall outcome ( major stroke or death ) occurred in 669 ( 37.0 % ) surgery-group patients and 442 ( 36.5 % ) control-group patients . The risk of major stroke or death complicating surgery ( 7.0 % ) did not vary substantially with severity of stenosis . On the other h and , the risk of major ischaemic stroke ipsilateral to the unoperated symptomatic carotid artery increased with severity of stenosis , particularly above about 70 - 80 % of the original luminal diameter , but only for 2 - 3 years after r and omisation . On average , the immediate risk of surgery was worth trading off against the long-term risk of stroke without surgery when the stenosis was greater than about 80 % diameter ; the Kaplan-Meier estimate of the frequency of a major stroke or death at 3 years was 26.5 % for the control group and 14.9 % for the surgery group , an absolute benefit from surgery of 11.6 % . However , consideration of variations in risk with age and sex modified this simple rule based on stenosis severity . We present a graphical procedure that should improve the selection of patients for surgery . INTERPRETATION Carotid endarterectomy is indicated for most patients with a recent non-disabling carotid-territory ischaemic event when the symptomatic stenosis is greater than about 80 % . Age and sex should also be taken into account in decisions on whether to operate OBJECTIVES Neurologic complications during  carotid artery stenting ( CAS ) are most clearly associated with embolization of visible debris . Distal filter devices may provide cerebr 
    Output:
    
Left-sided CE is consistently associated with higher postoperative adverse event rates .