***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: INTRODUCTION The purpose of this American Association for the Surgery of Trauma multicenter study is to assess the early efficacy and safety of endovascular stent grafts ( SGs ) in traumatic thoracic aortic injuries and compare outcomes with the st and ard operative repair ( OR ) . PATIENTS Prospect i ve , multicenter study . Data for the following were collected : age , blood pressure , and Glasgow Coma Scale ( GCS ) at admission , type of aortic injury , injury severity score , abbreviate injury scale ( AIS ) , transfusions , survival , ventilator days , complications , and intensive care unit and hospital days . The outcomes between the two groups ( open repair or SG ) were compared , adjusting for presence of critical extrathoracic trauma ( head , abdomen , or extremity AIS > 3 ) , GCS score < /=8 , systolic blood pressure < 90 mm Hg , and age > 55 years . Separate multivariable analysis was performed , one for patients without and one for patients with associated critical extrathoracic injuries ( head , abdomen , or extremity AIS > 3 ) , to compare the outcomes of the two therapeutic modalities adjusting for hypotension , GCS score < /=8 , and age > 55 years . RESULTS One hundred ninety-three patients met the criteria for inclusion . Overall , 125 patients ( 64.9 % ) were selected for SG and 68 ( 35.2 % ) for OR . SG was selected in 71.6 % of the 74 patients with major extrathoracic injuries and in 60.0 % of the 115 patients with no major extrathoracic injuries . SG patients were significantly older than OR patients . Overall , 25 patients in the SG group ( 20.0 % ) developed 32 device-related complications . There were 18 endoleaks ( 14.4 % ) , 6 of which needed open repair . Procedure-related paraplegia developed in 2.9 % in the OR and 0.8 % in the SG groups ( p = 0.28 ) . Multivariable analysis adjusting for severe extrathoracic injuries , hypotension , GCS , and age , showed that the SG group had a significantly lower mortality ( adjusted odds ratio : 8.42 ; 95 % CI : [ 2.76 - 25.69 ] ; adjusted p value < 0.001 ) , and fewer blood transfusions ( adjusted mean difference : 4.98 ; 95 % CI : [ 0.14 - 9.82 ] ; adjusted p value = 0.046 ) than the OR group . Among the 115 patients without major extrathoracic injuries , higher mortality and higher transfusion requirements were also found in the OR group ( adjusted odds ratio for mortality : 13.08 ; 95 % CI [ 2.53 - 67.53 ] , adjusted p value = 0.002 and adjusted mean difference in transfusion units : 4.45 ; 95 % CI [ 1.39 - 7.51 ] ; adjusted p value = 0.004 ) . Among the 74 patients with major extrathoracic injuries , significantly higher mortality and pneumonia rate were found in the OR group ( adjusted p values 0.04 and 0.03 , respectively ) . Multivariate analysis showed that centers with high volume of endovascular procedures had significantly fewer systemic complications ( adjusted p value 0.001 ) , fewer local complications ( adjusted p value p = 0.033 ) , and shorter hospital lengths of stay ( adjusted p value 0.005 ) than low-volume centers . CONCLUSIONS Most surgeons select SG for traumatic thoracic aortic ruptures , irrespective of associated injuries , injury severity , and age . SG is associated with significantly lower mortality and fewer blood transfusions , but there is a considerable risk of serious device-related complications . There is a major and urgent need for improvement of the available endovascular devices PURPOSE This trial evaluated the safety and effectiveness of thoracic endovascular aortic repair ( TEVAR ) with a contemporary endograft system compared with open surgical repair ( open ) of descending thoracic aortic aneurysms and large ulcers . METHODS Forty-two international trial sites enrolled 230 subjects with descending thoracic aortic aneurysms or ulcers . The study compared 160 TEVAR subjects treated with the Zenith TX2 Endovascular Graft  ( William Cook Europe , ApS , Bjaeverskov , Denmark ) with 70 open subjects . Subjects were evaluated preprocedure , predischarge , 1 , 6 , and 12 months , and yearly through 5 years with medical examination , laboratory testing , chest radiographs , and computed tomography scans . Mortality rates , prespecified severe morbidity composite index , major morbidity , clinical utility , aneurysm rupture , and secondary interventions were compared . The TEVAR subjects were evaluated by a core laboratory for device performance , including change in aneurysm size , endoleak , migration , and device integrity . RESULTS The 30-day survival rate was noninferior ( P < .01 ) for the TEVAR group compared with the open group ( 98.1 % vs 94.3 % ) . The severe morbidity composite index was lower for TEVAR ( 0.2 + /- 0.7 vs 0.7 + /- 1.2 ; P < .01 ) . Cumulative major morbidity scores were significantly lower at 30 days for the TEVAR group compared with the open group ( 1.3 + /- 3.0 vs 2.9 + /- 3.6 , P < .01 ) . The TEVAR patients had fewer cardiovascular , pulmonary , and vascular adverse events , although neurologic events were not significantly different . Clinical utility for the TEVAR patients was superior to that of the open patients . No ruptures or conversions occurred in the first year . Reintervention rates were similar in both groups . At 12 months , aneurysm growth was identified in 7.1 % ( 8/112 ) , endoleak in 3.9 % ( 4/103 ) , migration ( > 10 mm ) in 2.8 % ( 3/107 ) , and other device issues were rare . None of the patients with migration experienced endoleak , aneurysm growth , or required a secondary intervention . CONCLUSIONS Thoracic endovascular aortic repair with the TX2 is a safer and effective alternative to open surgical repair for the treatment of anatomically suitable descending thoracic aortic aneurysms and ulcers at 1 year of follow-up . Device performance issues are infrequent , but careful planning and regular follow-up with imaging remain a necessity Despite significant improvements in surgical techniques and perioperative management , the repair of descending thoracic aortic aneurysms remains a challenge with the potential for substantial morbidity and mortality . Over the past several years , buoyed by the technical success of endovascular repair of infrarenal abdominal aortic aneurysms , several case series reports of endovascular stent-graft placement for descending thoracic aortic aneurysms have demonstrated the potential safety and efficacy of this treatment modality . Several single-institution studies have documented promising results with these devices , but without controlled clinical trials , the data are insufficient to determine if thoracic aortic endografts provide equivalent or improved outcomes compared with st and ard open repair . We describe a study design of an ongoing prospect i ve , nonr and omized , multi-institutional , investigational device exemption phase II pivotal clinical trial investigating the safety and effectiveness of the Zenith TX2 thoracic aortic endovascular graft in the elective treatment of patients with descending thoracic aortic aneurysms OBJECTIVE The purpose of this study was to evaluate the safety and efficacy of a novel endovascular graft for elective treatment of infrarenal abdominal aortic aneurysm . The device is a modular bifurcated system with nitinol/exp and ed polytetrafluoroethylene components and a smaller profile than currently approved devices . METHODS In a multicenter , concurrent controlled phase II trial , 334 patients underwent treatment with the Excluder bifurcated endoprosthesis ( test , n = 235 ; W. L. Gore & Associates , Inc , Sunnyvale , Calif ) or with st and ard open repair ( control , n = 99 ) . Preoperative characteristics , perioperative variables , follow-up clinical evaluations , and radiographic examination results through the first 2 years were analyzed with univariable and multivariable statistics . RESULTS Patients in the test group had less blood loss ( 310 + /- 19 mL versus 1590 + /- 124 mL ; P < .0001 ) , fewer homologous transfusions ( 6 % versus 32 % ; P < .0001 ) , and shorter lengths of stay ( 2.0 + /- 0.1 days versus 9.8 + /- 1.4 days ; P < .0001 ) . Early major adverse events were markedly reduced in the test group ( 14 % versus 57 % ; P < .0001 ) , and this difference persisted at 2 years . No difference was seen in survival rate ( P = .13 ) . In the first 2 years , no deployment failure , early conversion , or aneurysm rupture occurred . At the 2-year timepoint , core laboratory read trunk migration in 1 % , limb migration in 1 % , limb narrowing in 1 % , endoleak in 20 % , and aneurysm growth in 14 % . One wire discontinuity ( 0.6 % ) was identified in a discharge film . A 7 % annual reintervention rate was seen in the test group in the first 2 years . SUMMARY The test device is a safe and effective treatment compared with open surgical repair for infrarenal abdominal aortic aneurysm . The most striking benefits are reduced blood loss , fewer complications , and faster recovery . Two-year survival rate was similar OBJECTIVE Results are presented from the first completed multicenter trial directed at gaining approval from the US Food and Drug Administration of endovascular versus open surgical repair of descending thoracic aortic aneurysms . METHODS Between September 1999 and May 2001 , 140 patients with descending thoracic aneurysms were enrolled at 17 sites and evaluated for a Gore TAG Thoracic Endograft . An open surgical control cohort of 94 patients was identified by enrolling historical and concurrent subjects . Patients were assessed before treatment , at treatment , and at hospital discharge and returned for follow-up visits at 1 month , 6 months , and annually thereafter . RESULTS One hundred thirty-seven of 140 patients had successful implantation of the  endograft .  Perioperative mortality in the endograft versus open surgical control cohort was 2.1 % ( n = 3 ) versus 11.7 % ( n = 11 , P < .001 ) . Thirty-day analysis revealed a statistically significant lower incidence of the following complications in the endovascular cohort versus the surgical cohort : spinal cord ischemia ( 3 % vs 14 % ) , respiratory failure ( 4 % vs 20 % ) , and renal insufficiency ( 1 % vs 13 % ) . The endovascular group had a higher incidence of peripheral vascular complications ( 14 % vs 4 % ) . The mean lengths of intensive care unit stay ( 2.6 + /- 14.6 vs 5.2 + /- 7.2 days ) and hospital stay ( 7.4 + /- 17.7 vs 14.4 + /- 12.8 days ) were significantly shorter in the endovascular cohort . At 1 and 2 years ' follow-up , the incidence of endoleaks was 6 % and 9 % , respectively . Through 2 years of follow-up , there were 3 re interventions in the endograft cohort and none in the open surgical control cohort . Kaplan-Meier analysis revealed no difference in overall mortality at 2 years . CONCLUSIONS In this multicenter study early outcomes with descending aortic endovascular stent grafting were very encouraging when compared with those of a well-matched surgical cohort . However , at 2 years ' follow-up , there is an incidence of endoleaks and re interventions associated with endovascular versus open surgical repair . Continued vigilant surveillance of patients treated with an endograft  is important BACKGROUND Endovascular stent graft ( EV ) technology has been successfully adapted to the repair of blunt traumatic aortic injuries . The purpose of this study was to compare the outcomes of patients treated with EV repair and open repair after blunt thoracic aortic trauma . METHODS A review of a tertiary trauma center 's prospect i ve trauma registry identified all patients who suffered a blunt traumatic thoracic aortic injury over an 11-year period ( 1991 - 2002 ) . Operative interventions and outcomes were then compared . RESULTS Over an 11-year period , 18 patients underwent repair of a blunt thoracic aortic injury ( EV , 6 ; open , 12 ) . There were no significant differences in demographics , injury , or crash statistics between groups . The open group had a 17 % early mortality rate ( n = 2 ) , a paraplegia rate of 16 % ( n = 2 ) , and an 8.3 % incidence of recurrent laryngeal nerve injury ( n = 1 ) . This is in contrast to a 0 % rate of mortality , paraplegia , and recurrent laryngeal nerve injury in the EV group . A definite tr 
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Metaregression to adjust for age imbalance , study design , and pathology did not material ly change the results .
Current data from nonr and omized studies suggest that TEVAR may reduce early death , paraplegia , renal insufficiency , transfusions , reoperation for bleeding , cardiac complications , pneumonia , and length of stay compared with open surgery .