***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 The Positive Impact of EndoVascular Options for Treating Aneurysms Early ( PIVOTAL ) trial enrolled individuals with small ( 4.0- to 5.0-cm diameter ) abdominal aortic aneurysms ( AAA ) and reported no difference in rupture or aneurysm-related death for patients who received early endovascular repair ( EVAR ) vs surveillance with serial imaging studies .  We evaluated re source use , medical cost , and quality of life outcomes associated with the PIVOTAL treatment strategies . METHODS This prospect i ve economic and quality of life study was conducted within a r and omized trial , with PIVOTAL sites participating in the quality of life ( n = 67 ) and economic ( n = 63 ) studies . The PIVOTAL trial r and omized 728 patients ( 366 early EVAR and 362 surveillance ) . We used information from 701 quality of life ( 351 early EVAR and 350 surveillance ) and 614 economic ( 314 early EVAR and 300 surveillance ) study participants enrolled in the PIVOTAL trial . The main outcome measures were total medical costs and the aneurysm repair rate at 48 months . RESULTS After 6 months , the rate of aneurysm repair was 96 vs 10 per 100 patients in the early EVAR and surveillance groups , respectively ( difference , 86 ; 95 % confidence interval [ CI ] , 82 - 90 ; P < .0001 ) , and total medical costs were greater in the early EVAR group ( $ 33,471 vs $ 5520 ; difference , $ 27,951 ; 95 % CI , $ 25,156-$30,746 ; P < .0001 ) . In months 7 through 48 , however , the rate of aneurysm repair was 54 per 100 patients in the surveillance group , and total medical costs were higher for patients in the surveillance vs the early EVAR group ( $ 40,592 vs $ 15,197 ; difference , $ 25,394 ; 95 % CI , $ 15,184-$35,605 ; P < .0001 ) . At 48 months ' follow-up , early EVAR patients had greater cumulative use of AAA repair ( 97 vs 64 per 100 patients ; difference , 34 ; 95 % CI , 21 - 46 ; P < .0001 ) , but there was no difference in total medical costs ( $ 48,669 vs $ 46,112 ; difference , $ 2557 ; 95 % CI , -$8043 to $ 13,156 ; P = .64 ) . After discounting at 3 % per annum , total medical costs for early EVAR and surveillance patients remained similar ( $ 47,765 vs $ 43,532 ; difference , 4232 ; 95 % CI , -$5561 to $ 14,025 ; P = .40 ) . There were no treatment-related differences in quality of life at 24 months . CONCLUSIONS A treatment strategy involving early repair of smaller AAA with EVAR is associated with no difference in total medical costs at 48 months vs surveillance with serial imaging studies . Longer follow-up is required to determine whether the late medical cost increases observed for surveillance will persist beyond 48 months BACKGROUND Although repair of large abdominal aortic aneurysms ( AAAs ) is well accepted , r and omized clinical trials have failed to demonstrate benefit for early surgical repair of small aneurysms compared with surveillance . Endovascular repair has been shown to be safer than open surgical repair in patients with large aneurysms , prompting a r and omized trial of early endovascular repair vs surveillance in patients with small aneurysms . METHODS We r and omly assigned 728 patients ( 13.3 % women ; mean age , 71 + /- 8 years ) with 4 to 5 cm AAAs to early endovascular repair ( 366 patients ) or ultrasound surveillance ( 362 patients ) .  Rupture or aneurysm-related death and overall mortality in the two groups were compared during a mean follow-up of 20 + /- 12 months . RESULTS Among patients r and omized to treatment , 89 % underwent aneurysm repair . Among patients r and omized to surveillance , 31 % underwent aneurysm repair during the course of the study . After a mean follow-up of 20 + /- 12 months ( range , 0 - 41 months ) , 15 deaths had occurred in each group ( 4.1 % ) . The unadjusted hazard ratio ( 95 % confidence interval ) for mortality after early endovascular repair was 1.01 ( 0.49 - 2.07 , P = .98 ) . Aneurysm rupture or aneurysm-related death occurred in two patients in each group ( 0.6 % ) . The unadjusted hazard ratio was 0.99 ( 0.14 - 7.06 , P = .99 ) for early endovascular repair . CONCLUSIONS Early treatment with endovascular repair and rigorous surveillance with selective aneurysm treatment as indicated both appear to be safe alternatives for patients with small AAAs , protecting the patient from rupture or aneurysm-related death for at least 3 years OBJECTIVE To investigate the feasibility of endurance exercise training in patients with small abdominal aortic aneurysm ( AAA ) , and to obtain preliminary data of its impact on important health outcomes . DESIGN R and omized controlled pilot study . SETTING University rehabilitation facility . PARTICIPANTS Patients with small AAA ( N=28 ; mean age ± SD , 72±7 y ) . INTERVENTION Participants were r and omized to a 12-week program of moderate-intensity endurance exercise or st and ard care control ( encouragement to exercise only ) . MAIN OUTCOME MEASURES Safety was assessed in terms of the frequency of adverse events and changes in maximum AAA diameter . Outcomes were assessed at baseline and 12 weeks including cardiopulmonary fitness ( ventilatory threshold ) , health-related quality of life ( Medical Outcomes Study 36-Item Short-Form Health Survey [ version 2 ] ) , and markers of vascular risk ( eg , blood pressure and high-sensitivity C-reactive protein ) . RESULTS Of 545 patients contacted , 28 ( 5 % ) entered the trial . There were 3 ( 11 % ) dropouts . Adherence to the exercise program was 94 % . There were no paradoxical increases in AAA size or adverse clinical events . Ventilatory threshold increased in the exercise group , but not the control group ( adjusted mean difference , 2.5 mL·kg(-1)·min(-1 ) ; 95 % confidence interval , 0.5 - 4.5 ; d=.82 ) . Systolic blood pressure and high-sensitivity C-reactive protein decreased in the exercise group compared with the control group ( d=.34 and d=.58 , respectively ) . There were no substantial changes in anthropometric variables or quality of life . CONCLUSIONS Despite a low recruitment rate , the findings suggest that moderate-intensity endurance exercise training is feasible in patients with small AAA , and can evoke improvements in important health outcomes BACKGROUND Endovascular repair of abdominal aortic aneurysm was originally developed for patients who were considered to be physically ineligible for open surgical repair .  Data are lacking on the question of whether endovascular repair reduces the rate of death among these patients . METHODS From 1999 through 2004 at 33 hospitals in the United Kingdom , we r and omly assigned 404 patients with large abdominal aortic aneurysms ( > or = 5.5 cm in diameter ) who were considered to be physically ineligible for open repair to undergo either endovascular repair or no repair ; 197 patients were assigned to undergo endovascular repair , and 207 were assigned to have no intervention .  Patients were followed for rates of death , graft-related complications and re interventions , and costs until the end of 2009 . Cox regression was used to compare outcomes in the two groups . RESULTS The 30-day operative mortality was 7.3 % in the endovascular-repair group . The overall rate of aneurysm rupture in the no-intervention group was 12.4 ( 95 % confidence interval [ CI ] , 9.6 to 16.2 ) per 100 person-years . Aneurysm-related mortality was lower in the endovascular-repair group ( adjusted hazard ratio , 0.53 ; 95 % CI , 0.32 to 0.89 ; P=0.02 ) . This advantage did not result in any benefit in terms of total mortality ( adjusted hazard ratio , 0.99 ; 95 % CI , 0.78 to 1.27 ; P=0.97 ) . A total of 48 % of patients who survived endovascular repair had graft-related complications , and 27 % required reintervention within the first 6 years . During 8 years of follow-up , endovascular repair was considerably more expensive than no repair ( cost difference , 9,826 pounds sterling [ U.S. $ 14,867 ] ; 95 % CI , 7,638 to 12,013 [ 11,556 to 18,176 ] ) . CONCLUSIONS In this r and omized trial involving patients who were physically ineligible for open repair , endovascular repair of abdominal aortic aneurysm was associated with a significantly lower rate of aneurysm-related mortality than no repair . However , endovascular repair was not associated with a reduction in the rate of death from any cause . The rates of graft-related complications and re interventions were higher with endovascular repair , and it was more costly . ( Current Controlled Trials number , IS RCT N55703451 . OBJECTIVES The UK Small Aneurysm Trial ( UKSAT ) and the American Aneurysm Detection and Management ( ADAM ) trial both concluded that early elective open surgery does not confer any late survival advantage in patients with small abdominal aortic aneurysm ( AAA ) with diameter 4.0 to 5.5 cm . However , two trials of endovascular aneurysm repair in small AAA have started based upon speculation that a sub-group of particularly fit patients , with low operative mortality , may benefit from early intervention . Here we investigate whether the fittest patients from the UKSAT might have benefited from early intervention . METHODS A total of 1090 patients r and omized into the UKSAT between 1991 and 1995 were followed for an average of 12 years for mortality . Baseline data were used to calculate the  Customized Probability Index ( CPI ) , a vali date d prognostic risk score for operative mortality after elective open aneurysm repair that assigns risk points for history of cardiac , pulmonary , and renal disease and subtracts risk points for use of statins and beta-blockers . Cox regression was used to assess any differences in all-cause or aneurysm-related mortality between policies of early surgery or surveillance across the fitness spectrum . Tests for interaction used CPI scores as a continuous variable but patients also were stratified into tertile groups for descriptive purpose s. Hazard ratios were adjusted for age , gender , and aneurysm diameter . RESULTS A total of 714 deaths ( 95 aneurysm-related ) occurred in 8485 person-years ( number of patients multiplied by average years of conditional follow-up ) . The mean ( st and ard deviation [ SD ] ) CPI score was 8.1 ( 9.9 ) with similar scores between r and omized groups . The tertile groups had mean ( SD ) scores of -1.8 ( 3.7 ) for the 389 fittest patients , 8.8 ( 3.3 ) for the 438 moderately fit , 21.4 ( 6.6 ) for the 261 least fit with missing scores in 2 patients . The tests for interaction were non-significant for both all-cause ( P = .176 ) and aneurysm-related mortality ( .178 ) . However , for the least fit patients a survival advantage was seen in the early surgery group ; adjusted hazard ratios 0.73 ( 95 % confidence interval [ CI ] 0.56 - 0.96 ) and 0.46 ( 95 % CI 0.22 - 0.98 ) for all-cause and aneurysm-related mortality respectively . CONCLUSION Early elective surgery did not confer any survival benefit in the fittest patients . On the contrary , the possibility of a survival benefit from early intervention in patients of poor fitness merits further investigation through meta- analysis or validation in other prospect i ve studies BACKGROUND Although the initial results of endovascular repair of abdominal aortic aneurysms were promising , current evidence from controlled studies does not convincingly show a reduction in 30-day mortality relative to that achieved with open repair . METHODS We conducted a multicenter , r and omized trial comparing open repair with endovascular repair in 345 patients who had received a diagnosis of abdominal aortic aneurysm of at least 5 cm in diameter and who were considered suitable c and i date s for both techniques . The outcome events analyzed were operative ( 30-day ) mortality and two composite end points of operative mortality and severe complications and operative mortality and moderate or severe complications . RESULTS The operative mortality rate was 4.6 percent in the 
    Output:
    
The results from the four trials to date demonstrate no advantage to immediate repair for small AAA ( 4.0 cm to 5.5 cm ) , regardless of whether open or endovascular repair is used and , at least for open repair , regardless of patient age and AAA diameter .
Thus , neither immediate open nor immediate endovascular repair of small AAAs is supported by currently available evidence