***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: Objective To compare the late clinical outcome and incidence of recurrent stenosis  after carotid endarterectomy ( CEA ) with polytetrafluoroethylene ( PTFE ) versus Hemashield patching . Summary Background Data Several r and omized trials have confirmed the advantages of patching over primary closure when performing CEA . Methods Two hundred CEAs ( 180 patients ) were r and omized into 100 with PTFE patching and 100 with Hemashield . All patients underwent postoperative color duplex ultrasounds  at 1 , 6 , and 12 months , and every year thereafter . The mean follow-up was 26 months . Kaplan-Meier analysis was used to estimate the risk of re-stenosis , stroke , and stroke-free survival . A multivariate analysis of various risk factors was also done . Results Demographic and clinical characteristics were similar in both groups . The incidence of all ipsilateral strokes ( early and late ) was 8 % ( 7 % perioperative ) for Hemashield versus 0 % for PTFE patching . Both groups had similar mortality rates . The cumulative stroke-free rates at 6 , 12 , 24 , and 36 months were 93 % , 93 % , 93 % , and 89 % for Hemashield versus 100 % , 100 % , 100 % , and 100 % for PTFE patching . The cumulative stroke-free survival rates at 6 , 12 , 24 , and 36 months were 90 % , 89 % , 87 % , and 79 % for Hemashield versus 98 % , 98 % , 92 % , and 92 % for PTFE patching .  Kaplan-Meier analysis also showed that freedom from 50 % or greater re-stenosis at 6 , 12 , 24 , and 36 months was 89 % , 81 % , 73 % , and 66 % for Hemashield versus 100 % , 100 % , 100 % , and 92 % for PTFE . Similarly , the freedom from 70 % or greater re-stenosis at 6 , 12 , 24 , and 36 months was 93 % , 91 % , 86 % , and 78 % for Hemashield versus 100 % , 100 % , 100 % , and 100 % for PTFE . Univariate and multivariate analyses of demographic and preoperative risk factors showed that only Hemashield was significantly associated with a higher incidence of 70 % or greater recurrent stenosis . Conclusions PTFE patching was superior to Hemashield in lowering the incidence of postoperative ipsilateral strokes and late recurrent stenosis The effect of clinical trials on clinical practice has been especially notable in the field of cerebrovascular surgery , and carotid endarterectomy in particular . Extensive data have been published from retrospective studies in cerebrovascular disease ; the current focus on prospect i ve r and omized trials does not discount the validity of these prior studies . Nevertheless , prospect i ve r and omized trials have several distinct scientific advantages in showing causality , or the cause- and -effect relationship between treatment ( eg , surgery ) and outcome ( eg , stroke or perioperative death ) . Retrospective analyses , however , are subject to a number of factors that may bias the interpretation of data . Prospect i ve r and omized trials have become one st and ard by which surgical procedures are judged and from which practice guidelines and reimbursement schedules are derived , thus ultimately determining their application in clinical practice OBJECTIVE The objective of this study was the determination of whether the choice of either autogenous saphenous vein ( ASV ) or synthetic material for patch angioplasty significantly influences the results after carotid endarterectomy ( CEA ) . METHODS With Institutional Review Board approval , 195 patients ( 145 men and 50 women ; mean age , 69 years ) who underwent 207 CEAs were prospect ively r and omized to arteriotomy closure with ASV or synthetic patches from July 1996 to January 2000 . One hundred and one patients ( 52 % ) were r and omized to the ASV cohort , and 94 ( 48 % ) were r and omized to the synthetic cohort .  Aside from a slight gender imbalance ( 70 % versus 79 % male in the ASV versus the synthetic group ) , there were no clinical ly important differences in baseline demographic variables , risk factors , or surgical indications between the ASV and synthetic groups . RESULTS With all 207 r and omized procedures on an intent-to-treat basis , there were two early ( < 30 days ) postoperative deaths ( 1 % ) . There were three perioperative strokes in the ASV cohort ( 3.0 % ) and two in the synthetic cohort ( 2.1 % ; P = .99 ) . Two of these early strokes occurred in a subset of nine patients who received neither patch material , all after r and omization but before CEA . Two patients in each group had late strokes . The cumulative freedom from stroke rate at 1 year ( ASV , 94 % ; synthetic , 95 % ) was virtually identical for both cohorts . With the 125 patients who had at least one postoperative duplex scan , the incidence rate of recurrent ( > or=60 % ) carotid stenosis was 4.8 % ( three of 62 ) for the ASV group and 6.3 % ( four of 63 ) for the synthetic group ( P = .99 ) . CONCLUSION No significant differences in the stroke , mortality , or restenosis rates were shown between the ASV and the synthetic cohorts . While conceding the power limitations inherent in this study , we conclude that CEA may be safely performed with similar early results with ASV or synthetic patches INTRODUCTION The use of synthetic patch angioplasty during carotid endarterectomy ( CEA ) has been advocated to reduce restenosis , stroke , and death , but the type of material used is still being debated . This study compared rate of restenosis , neurologic events , and perioperative death in patients undergoing CEA with primary closure versus polyester urethane patch closure .  PATIENTS AND METHODS In a prospect i ve r and omized study , we compared patch angioplasty with polyester urethane ( Vascular-patch , B. Braun Medical AG , Tuttlingen , Germany ) to primary closure between February 1999 and March 2002 in 404 operations . Early ( 30-day ) stroke and mortality rate , long-term restenosis , and neurologic events were compared in the two groups during 2.5 to 5 years of follow-up ( median follow-up , 2 years ) . RESULTS  Primary closure  was used in 216 operations , and patch angioplasty was used in 206 . Clamping time was significantly shorter in the primary closure group ( P < .001 ) . Perioperative mortality and neurologic events were similar in both groups ( 1.9 % vs 3.9 % , P = .21 , odds ratio [ OR ] , 2.1 ; 95 % confidence interval [ CI ] , 0.56 to 9.85 ) . The rate of residual stenosis ( > or = 50 % ) at 0 or 3-month follow-up was significantly lower in the patch group ( 2 operations , 1.1 % ) compared with the primary closure group ( 17 operations , 8.9 % ) ( P = .001 , OR , 0.114 ; 95 % CI , 0.026 to 0.5 ) . Multivariable logistic regression showed that only primacy closure was found to influence residual stenosis . Restenosis of 70 % was significantly less in the patch angioplasty group ( 2.2 % vs 8.6 % ) ( P = . 01 , hazard ratio , 0.246 ; 95 % CI , 0.08 to 0.75 ) . No correlation was found between restenosis and gender , preoperative symptoms , or risk factors . CONCLUSIONS Patch angioplasty with polyester urethane significantly reduced the restenosis rate ( P = . 01 ) compared with primary closure . Even though clamping time was longer , patching was not associated with more perioperative complications PURPOSE The early outcomes of carotid endarterectomy ( CEA ) with primary closure ( PC )  versus vein patch closure ( saphenous vein [ SVP ] and jugular vein [ JVP ] ) and polytetrafluoroethylene patch closure ( PTFE-PC ) were compared . METHODS Three hundred ninety-nine CEAs were r and omized into the following groups : 135 PC , 134 PTFE-PC , and 130 vein patch closure ( SVP alternating with JVP ) . Surviving patients underwent a carotid color duplex ultrasonographic scan 1 month after surgery . Demographic characteristics were similar in all groups . RESULTS The incidence of perioperative cerebrovascular accidents ( CVAs ) was 4.4 % for PC , 0.8 % for PTFE-PC , and 0 % for vein patch closure ( PC vs vein patch , p = 0.0165 ; PC vs all patching [ vein and PTFE ] , p = 0.007 ) . The perioperative CVA and reversible ischemic neurologic deficit ( RIND ) combined rates for all patching were superior to PC ( 1.5 % vs 5.2 % ; p = 0.04 ) . These combined rates were also superior for vein patch closure when compared with PC ( 0.8 % vs 5.2 % ; p = 0.037 ) . The mean diameter of the internal carotid artery was similar in patients who had perioperative neurologic deficits and those who did not . After 1 month of follow-up , 11.9 % of the PC arteries were narrowed 50 % or more in contrast to 2.3 % for PTFE-PC , 3.1 % for SVP , and 10.3 % for JVP Although carotid patch angioplasty has been performed on a selective or routine basis in all large series of carotid endarterectomy , the choice of patch material still remains in question . The objective of this study has been a prospect i ve r and omized evaluation of the relative risks and benefits of saphenous vein patch versus PTFE patch material for carotid endarterectomy . During a 4-year period , 84 patients undergoing 95 carotid endarterectomies were r and omized into two groups : 45 venous patch ( n = 40 ) and 50 PTFE patch ( n = 44 ) . All operations were carried out under general anesthesia and systematic placement of a shunt . The patients were evaluated at 1 , 3 , 6 months and every year with doppler , periorbitary photoplethysmography , intravenous digital subtraction angiography , and neurologic assessment ( mean follow-up 29 + /- 1 month ) . Operative time among patients having PTFE patch was significantly longer ( p < 0.05 ) than among those having saphenous vein patch , due to bleeding from suture holes . Perioperatively , no neurologic complications or deaths were observed in venous patch patients , however there was a permanent stroke and one death from arterial wall disruption in the PTFE patch group . The incidence of aneurysmal dilatation in the saphenous vein patch group ( 15.5 % ) was higher than for the PTFE patch group ( 2 % ) . On late follow-up , no deaths , carotid thrombosis or patch rupture were observed in either group . Recurrent stenosis occurred in 2 cases having PTFE patch . One reoperation for recurrence was required . In addition , one patient with PTFE patch angioplasty developed an infected false aneurysm at 7 months . ( ABSTRACT TRUNCATED AT 250 WORDS During a 4-year period , 136 patients undergoing 152 carotid endarterectomies consented to be r and omized to primary or saphenous vein patch closure of the arteriotomy . At operation , before r and omization , careful assessment of arterial dimensions and anatomy was made . Patients who had an internal carotid artery ( ICA ) diameter less than 5 mm , arteriotomy extending more than 3 cm beyond the origin of the ICA , or tortuous or kinked ICAs were not r and omized ; they received obligatory vein patch closure ( necessary in 20 % cases ) . All patients were followed up every 3 months for 1 year and every 6 months thereafter with duplex scanning , ocular pneumoplethysmography , and neurologic assessment . The incidence of atherosclerotic risk factors was equal in the groups and all except one of the patients were male .  Perioperative morbidity was not significantly different among those having primary closure ( n = 60 ) , saphenous vein patch closure ( n = 62 ) , and obligatory vein patch closure ( n = 30 ) . Operative time among patients having primary closure ( 122 + /- 4 minutes ) was significantly less ( p less than 0.001 ) than among those having saphenous vein patch closure ( 150 + /- 3 minutes ) . Three perioperative strokes were evenly distributed among the groups ( 2 % for all procedures ) ; no deaths and no acute postoperative occlusions occurred . Recurrent disease occurred in 12.9 % of patients having saphenous vein patch closure compared with its occurrence in 1.7 % of those having primary closure ( p less than 0.05 ) . However , most recurrences were moderate stenoses ( 25 % to 50 % diameter reduction ) , all were smooth-surfaced , and none required a second operation . All except one of the recurrences among those patients with saphenous vein patch closure were in the bulb and the origin of the ICA ; two had evidence of regression 
    Output:
    
The hemostasis time in CEA with PTFE patch was longer than with venous patch or Dacron patch .
The overall perioperative and long-term mortality rate , stroke rate , restenosis , and operative time were similar when using venous patch versus synthetic patch material or Dacron patch versus PTFE patch material during CEA .