***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background and Purpose — Race/ethnic-based disparities in the utilization of health-related services have been reported . Data collected as part of the Veterans Administration Acute Stroke Study ( VASt ) were analyzed to determine whether similar differences were present in patients admitted to Veterans Administration ( VA ) hospitals with acute ischemic stroke . Methods — VASt prospect ively identified stroke patients admitted to 9 geographically separated VA hospitals between April 1995 and March 1997 . Demographic characteristics and all inpatient diagnostic tests/ procedures were recorded . Frequencies were compared with & khgr;2 tests . Results — Of 1073 enrolled patients , 775 ( white , n=520 ; nonwhite , n=255 , including 226 blacks and 28 Hispanic-Americans ) with ischemic stroke were admitted from home . Mean ages ( 71.0±0.6 versus 71.9±0.4 years;P = 0.25 ) and Trial of ORG 10172 in Acute Stroke Treatment ( TOAST ) stroke types ( atherothrombotic , 12.9 % versus 13.3 % ; cardioembolic , 16.5 % versus 18.0 % ; lacunar , 26.4 % versus 27.1 % ; other , 1.4 % versus 2.0 % ; unclassified , 42.9 % versus 39.6%;P = 0.89 ) for whites versus nonwhites were similar . There were no race/ethnic-based differences in the utilization of brain CT  ( 91.0 % versus 92.2%;P = 0.58 ) ,  MRI  ( 36.2 % versus 41.6%;P = 0.14 ) , transthoracic ( 52.5 % versus 53.7%;P = 0.75 ) or transesophageal echocardiography ( 10.2 % versus 10.6%;P = 0.86 ) , 24-hour ECG ( 3.3 % versus 1.6%;P = 0.17 ) , carotid ultrasound ( 64.0 % versus 62.0%;P = 0.57 ) , carotid endarterectomy ( 1.5 % versus 0.8%;P = 0.38 ) , rehabilitation evaluations ( 71.0 % versus 76.5%;P = 0.11 ) , speech therapy ( 9.6 % versus 12.6%;P = 0.21 ) , recreational therapy ( 3.1 % versus 2.0%;P = 0.37 ) , or occupational therapy ( 16.0 % versus 19.6%;P = 0.20 ) for whites versus nonwhites , respectively . Angiography was performed less frequently ( 3.1 % versus 8.5%;P = 0.01 ) and ECG more frequently ( 81.6 % versus 73.5%;P = 0.01 ) in nonwhites . The proportions of patients discharged functionally independent were also similar ( 52 % of whites and 50 % of nonwhites had discharge Rankin Scale scores of 0 , 1 , or 2;P = 0.63 ) . Conclusions — Aside from cerebral angiography and ECG , there were no race/ethnic-based disparities in the utilization of a variety of stroke-related procedures and services . The difference in the use of angiography is unlikely to be related to a difference in screening for carotid endarterectomy because there was no difference in the frequency of carotid ultrasonography . The reason ECG was obtained more frequently in nonwhites is uncertain Background and Purpose R and omized clinical trials have shown that carotid endarterectomy decreases the risk of subsequent stroke in patients with high- grade carotid stenosis and ipsilateral transient ischemic attack or minor stroke . The benefit of surgery is highly dependent on surgical risk . We previously found that patients with ipsilateral hemispheric symptoms were at greater risk of carotid endarterectomy complications compared with those who were asymptomatic or had nonipsilateral symptoms . The goals of the present study were ( 1 ) to identify preoperative clinical factors that may increase the risk of complications after  carotid endarterectomy  in patients with ipsilateral hemispheric symptoms and ( 2 ) to develop a risk index based on this patient-level data . Methods Records from 1160 carotid endarterectomies performed at 12 academic medical centers composed the primary data set . Hospital charts for the admission during which carotid endarterectomy was performed were systematic ally review ed by abstract ors using a defined protocol . The present analysis was carried out on data from the subset of patients who had carotid endarterectomy for ipsilateral hemispheric symptoms . C and i date variables were identified based on univariate Fisher 's exact tests or x2 tests . A risk index was then developed using those variables with a greater than 90 % probability of being associated with adverse outcomes . Results Of the 697 patients with ipsilateral symptoms , 8.5 % had either stroke , myocardial infa rct ion , or died during the postoperative period of hospitalization . Those over the age of 75 had a greater risk of myocardial infa rct ion ( 6.6 % versus 2.3 % , P=.024 ) but not of stroke or death ( P<.10 ) . The overall frequencies of adverse outcomes were also higher in the 5 patients with complete ipsilateral carotid occlusions ( 40 % versus 8.2 % , p<.01 ) , the 28 patients with ipsilateral intraluminal thrombus ( 17.9 % versus 8.1 % , P=.01 ) , and the 65 patients with ipsilateral carotid siphon stenosis ( 13.9 % versus 7.9 % , P=.10 ) . There were no differences in adverse outcomes among those with different degrees of ipsilateral stenosis ( 30 % to 49 % , 50 % to 69 % , and 70 % to 99 % ) . Adverse outcome rates were similar regardless of the type of symptom ( transient ischemic attack , recent ipsilateral minor stroke , remote ipsilateral minor stroke ) . There were no significant differences in adverse outcome rates based on sex , race , history of angina , recent myocardial infa rct ion , congestive heart failure , chronic obstructive pulmonary disease , hypertension , degree of stenosis of the contralateral carotid artery , or presence of ulceration in the ipsilateral artery ( Fisher 's exact tests , P>.10 ) . A count of variables with greater than 90 % probability of being associated with adverse outcomes ( age ≤75 years or angiographic evidence of ipsilateral carotid occlusion , stenosis in the region of the carotid siphon , or intraluminal thrombus ) was used to form a simple risk index . “ High-risk ” patients ( one or more risk factors ) had more than two times the risk of complications compared with “ low-risk ” patients who had no risk factors ( odds ratio , 2.18 ; 95 % confidence interval , 1.25 to 3.81 ) . Conclusions Certain preoperative clinical variables may place patients with ipsilateral symptoms at greater risk of perioperative complications after  carotid endarterectomy  . Prospect i ve validation of a simple risk index would provide an additional method for assessing preoperative risk in endarterectomy c and i date Context . Black patients and Hispanic patients receive carotid endarterectomy ( CEA ) at lower rates than white patients . It is unclear whether worse surgical outcomes are influencing clinical decision-making regarding use of the operation among minority group patients . Objective . To determine if there are racial differences in postoperative outcomes for patients undergoing CEA at Veterans Affairs ( VA ) medical centers . Design . Secondary analysis of data from an ongoing , prospect i ve study on surgical quality and outcomes in the VA health care system . Setting . One hundred thirty-two VA Medical Centers that were part of the VA National Surgical Quality Improvement Program . Patients . A cohort of 6551 men ( 91.4 % white , 5.3 % black , and 3.3 % Hispanic ) who had CEA performed between October 1 , 1994 and September 30 , 1997 . Main Outcome Measures . Primary outcomes were stroke or death and stroke , myocardial infa rct ion ( MI ) , or death within 30 days of the operation . Results . Thirty-day postoperative rates of stroke or death and of stroke , MI , or death were generally low for all racial/ethnic groups , ranging between 2.6 % and 6.5 % . Within clinical states that define indications for CEA , rates were also low ( 1.6 % to 3.2 % ) among asymptomatic patients across racial/ethnic groups . However , among patients with transient ischemic attack ( TIA ) , Hispanic patients had significantly worse outcomes than white patients with a postoperative rate of stroke or death of 10.5 % ( P < 0.05 ) and stroke , MI , or death of 13.2 % ( P < 0.05 ) compared with 3.1 % to 3.5 % for white patients . Hispanic patients did not differ from black patients for stroke , death/stroke , death , or MI . Conclusion . Rates of major postoperative complications after CEA are low within the VA and similar across racial/ethnic groups with the possible exception of Hispanic men with TIA . Further investigation of this elevated complication rate among Hispanic men with TIA may be warranted OBJECTIVE To determine whether the addition of carotid endarterectomy to aggressive medical management can reduce the incidence of cerebral infa rct ion in patients with asymptomatic carotid artery stenosis . DESIGN Prospect i ve , r and omized , multicenter trial . SETTING Thirty-nine clinical sites across the United States and Canada . PATIENTS Between December 1987 and December 1993 , a total of 1662 patients with asymptomatic carotid artery stenosis of 60 % or greater reduction in diameter were r and omized ; follow-up data are available on 1659 . At baseline , recognized risk factors for stroke were similar between the two treatment groups . INTERVENTION Daily aspirin administration and medical risk factor management for all patients ; carotid endarterectomy for patients r and omized to receive surgery . MAIN OUTCOME MEASURES Initially , transient ischemic attack or cerebral infa rct ion occurring in the distribution of the study artery and any transient ischemic attack , stroke , or death occurring in the perioperative period . In March 1993 , the primary outcome measures were changed to cerebral infa rct ion occurring in the distribution of the study artery or any stroke or death occurring in the perioperative period . RESULTS After a median follow-up of 2.7 years , with 4657 patient-years of observation , the aggregate risk over 5 years for ipsilateral stroke and any perioperative stroke or death was estimated to be 5.1 % for surgical patients and 11.0 % for patients treated medically ( aggregate risk reduction of 53 % [ 95 % confidence interval , 22 % to 72 % ] ) . CONCLUSION Patients with asymptomatic carotid artery stenosis of 60 % or greater reduction in diameter and whose general health makes them good c and i date s for elective surgery will have a reduced 5-year risk of ipsilateral stroke if carotid endarterectomy performed with less than 3 % perioperative morbidity and mortality is added to aggressive management of modifiable risk factors Abstract Black men are 2.5 times as likely to die of stroke as white men . 1 Black women are 2.4 times as likely to die of stroke as white women . 1 In Los Angeles County , stroke accounted for a greater percentage of the deaths from cardiovascular disease among blacks and Hispanics than among non-Hispanic whites and Asians . 2 Elderly blacks have a higher prevalence of atherothrombotic brain infa rct ion ( ABI ) than elderly whites or Hispanics . 3 Patients with extracranial carotid arterial disease ( ECAD ) diagnosed by carotid duplex ultrasonography have at follow-up an increased incidence of ABI . 4–8 We are reporting data from a prospect i ve study investigating the prevalence of ECAD with 40 to 100 % arterial luminal diameter decrease and of ABI , and their association in 1,063 elderly blacks , Hispanics and whites OBJECTIVE --To audit the outcome in patients with subarachnoid haemorrhage ( SAH ) after a change in management strategy . METHODS --A retrospective analysis of patients with aneurysmal subarachnoid haemorrhage over a 20 month period ( phase 1 ) was followed by a prospect i ve analysis of patients presenting during the next 20 months ( phase 2 ) in which a protocol driven management regime of immediate intravenous fluid resuscitation and earlier surgery  was pursued . Patients in this phase were grouped into those receiving early ( within four days of subarachnoid haemorrhage ) and late ( after four days of subarachnoid haemorrhage ) surgery . In phase 1 , 75 out of a total of 92 patients underwent surgery on ( median ) day 12 . From phase 2 , 109 patients out of a total of 129 underwent surgery on ( median ) day 4 , 58 of which had their surgery within 4 days of the subarachnoid haemorrhage . Patients in each phase/group were well matched for demographic features , site of aneurysm , and severity of subarachnoid haemorrhage . RESULTS --The surgical morbid 
    Output:
    
Our systematic review found evidence of racial disparities in the surgical treatment of patients with carotid stenosis and aneurysmal subarachnoid hemorrhage .
Conclusion Results of this comprehensive literature review suggest that racial disparities in cerebrovascular disease are understudied .