***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: To comprehend the results of a r and omised controlled trial ( RCT ) , readers must underst and its design , conduct , analysis , and interpretation . That goal can be achieved only through total transparency from authors . Despite several decades of educational efforts , the reporting of RCTs needs improvement . Investigators and editors developed the original CONSORT ( Consoli date d St and ards of Reporting Trials ) statement to help authors improve reporting by use of a checklist and flow diagram . The revised CONSORT statement presented here incorporates new evidence and addresses some criticisms of the original statement . The checklist items pertain to the content of the Title , Abstract , Introduction , Methods , Results , and Discussion . The revised checklist includes 22 items selected because empirical evidence indicates that not reporting this information is associated with biased estimates of treatment effect , or because the information is essential to judge the reliability or relevance of the findings . We intended the flow diagram to depict the passage of participants through an RCT . The revised flow diagram depicts information from four stages of a trial ( enrolment , intervention allocation , follow- up , and analysis ) . The diagram explicitly shows the number of participants , for each intervention group , included in the primary data analysis . Inclusion of these numbers allows the reader to judge whether the authors have done an intention- to-treat analysis . In sum , the CONSORT statement is intended to improve the reporting of an RCT , enabling readers to underst and a trial 's conduct and to assess the validity of its results There is an interest in the consequences of deriving a single index measure of health for validity and sensitivity . This paper presents the results of testing a recent example of a general health measure design ed to derive a single index , the Euroqol ( EQ ) , and presents a comparison with a new , influential profile measure , the Short Form 36 ( SF-36 ) Health Survey Instrument . The EQ and an anglicised version of the SF-36 health survey , both design ed for self-completion , were included in a postal survey of a r and om sample of 1980 patients from two practice lists in Sheffield , UK . The response rate for the EQ question naire was 83 % , and the rate of completion over 95 % . Evidence was found for the construct validity of the EQ dimension responses and the derived total EQ health score in terms of distinguishing between groups with expected health differences . Considerable agreement was found between EQ responses and the total EQ score , and the UK SF-36 profile scores . There was substantial evidence of EQ being less sensitive at the ceiling ( i.e. low levels of perceived ill-health ) and throughout the range of health states . A recent restructuring of the EQ , may help overcome some of the problems with the physical dimensions by reducing their skewness In clinical research , r and omized trials are widely accepted as the definitive method of evaluating the efficacy of therapies . The r and om assignment of patients to their treatment ensures the internal validity of the comparison of new treatments with controls . An assessment of the external validity of trial results can best be achieved by comparing the study population to the population of patients who met the eligibility criteria but did not consent to r and omization . A part of the data of the Coronary Artery Surgery Study ( CASS ) , in which coronary artery bypass surgery is compared to conventional medical therapy in patients with coronary artery disease , is used to illustrate a strategy of multivariate analysis of r and omized and nonr and omized patients which allows an investigation of both internal and external validity . The method used Cox 's proportional hazards regression model with inclusion of covariates for r and omization status and corresponding interactions in addition to the usual covariates for treatment and the important prognostic factors BACKGROUND Percutaneous revascularization is a well-accepted method of treatment for a single left anterior descending coronary artery ( LAD ) stenosis . With the introduction of primary stenting , it has become the treatment of choice for a LAD lesion . In the last few years however , the introduction of minimally invasive cardiac surgery , video-assisted left internal thoracic artery ( LITA ) harvesting , and robotic surgery have raised the question as to whether minimally invasive surgical revascularization would be competitive with percutaneous coronary interventions in cases of single-vessel stenoses . METHODS A group of 100 patients with Canadian Cardiovascular Society class II to IV , and angiographically confirmed single critical stenosis of the LAD ( type A or B ) , were treated with direct primary stenting ( group 1 , n = 50 ) , or with endoscopic atraumatic coronary artery bypass grafting ( group 2 , n = 50 ) . RESULTS All patients in a group 1 , obtained a very good angiographic and clinical effect . No acute postoperative complications were noted at 1 month of follow-up . However , at 1 month of follow-up , 3 patients ( 6 % ) developed restenosis of the LAD , and at 6 months follow-up , 6 patients ( 12 % ) , developed restenosis of the LAD . In these cases , repeated percutaneous coronary interventions of the target vessel were successfully performed . In group 2 , very good operative results were observed . In 1 and 6 months of follow-up , all patients remained asymptomatic . Critical stenosis of the left internal thoracic artery-LAD anastomosis was angiographically documented in 1 case ( 2 % ) . This patient was successfully treated with balloon angioplasty . CONCLUSIONS The study results document the superiority of endoscopic atraumatic coronary artery bypass grafting over direct primary stenting in LAD revascularization , along with the slightly higher costs of the surgical procedure BACKGROUND Minimally invasive bypass surgery and coronary-artery stenting are both accepted treatments for isolated stenosis of the proximal left anterior descending coronary artery . We compared the clinical outcomes after these two procedures . METHODS A total of 220 symptomatic patients with high- grade lesions in the proximal left anterior descending coronary artery were r and omly assigned to treatment--110 to surgery and 110 to stenting .  The combined clinical end point was freedom from major adverse cardiac events , such as death from cardiac causes , myocardial infa rct ion , and the need for repeated revascularization of the target lesion within six months . RESULTS A major adverse cardiac event occurred in 31 percent of patients after stenting , as compared with 15 percent in the surgery group ( P=0.02 ) . The difference was predominantly due to a higher rate of repeated revascularization of the target vessel for restenosis after stenting ( 29 percent vs. 8 percent , P=0.003 ) . The combined rates of death and myocardial infa rct ion did not differ significantly between groups ( 3 percent in the stenting group and 6 percent in the surgery group , P=0.50 ) . Adverse events occurred more frequently after surgery . The percentage of patients free from angina after six months was 79 percent in the surgery group , as compared with 62 percent in the stenting group ( P=0.03 ) . CONCLUSIONS In patients with isolated high- grade lesions of the proximal left anterior descending artery , both minimally invasive bypass surgery and stenting are effective . Stenting yields excellent short-term results with fewer periprocedural adverse events , but surgery is superior with regard to the need for repeated intervention in the target vessel and freedom from angina at six months of follow-up BACKGROUND R and omized studies have shown that the use of coronary-artery stenting as the initial treatment for coronary stenosis is associated with a lower risk of restenosis than is st and ard coronary angioplasty . We prospect ively investigated the efficacy of these two approaches in selected patients with isolated stenosis of the proximal left anterior descending coronary artery . METHODS A total of 120 patients with isolated stenosis of the proximal left anterior descending coronary artery were r and omly assigned to stent implantation or st and ard coronary angioplasty . The primary clinical end points were the rate of procedural success ( defined as residual stenosis of less than 50 percent and the absence of death , myocardial infa rct ion , and the need for coronary-artery bypass surgery during the hospital stay ) and the rate of event-free survival ( defined as freedom from death , myocardial infa rct ion , and the recurrence of angina ) at 12 months . The angiographic end point was the rate of restenosis 12 months after the procedure . RESULTS The two treatment groups did not differ significantly with respect to demographic , clinical , or angiographic characteristics . The rates of procedural success were similar in the two groups of patients ( 95 percent in the stenting group vs. 93 percent in the angioplasty group , P = 0.98 ) . The 12-month rates of event-free survival were 87 percent after stenting and 70 percent after angioplasty ( P = 0.04 ) . The rates of restenosis were 19 percent after stent implantation and 40 percent after angioplasty ( P = 0.02 ) . CONCLUSIONS In patients with symptomatic isolated stenosis of the proximal left anterior descending coronary artery , stenting had advantages over st and ard coronary angioplasty in that it was associated with both a lower rate of restenosis and a better clinical outcome BACKGROUND Coronary-stent placement is a new technique in which a balloon-exp and able , stainless-steel , slotted tube is implanted at the site of a coronary stenosis . The purpose of this study was to compare the effects of stent placement and st and ard balloon angioplasty on angiographically detected restenosis and clinical outcomes . METHODS We r and omly assigned 410 patients with symptomatic coronary disease to elective placement of a Palmaz-Schatz stent or to st and ard balloon angioplasty . Coronary angiography was performed at base line , immediately after the procedure , and six months later . RESULTS The patients who underwent stenting had a higher rate of procedural success than those who underwent st and ard balloon angioplasty ( 96.1 percent vs. 89.6 percent , P = 0.011 ) , a larger immediate increase in the diameter of the lumen ( 1.72 + /- 0.46 vs. 1.23 + /- 0.48 mm , P < 0.001 ) , and a larger luminal diameter immediately after the procedure ( 2.49 + /- 0.43 vs. 1.99 + /- 0.47 mm , P < 0.001 ) . At six months , the patients with stented lesions continued to have a larger luminal diameter ( 1.74 + /- 0.60 vs. 1.56 + /- 0.65 mm , P = 0.007 ) and a lower rate of restenosis ( 31.6 percent vs. 42.1 percent , P = 0.046 ) than those treated with balloon angioplasty . There were no coronary events ( death ; myocardial infa rct ion ; coronary-artery bypass surgery ; vessel closure , including stent thrombosis ; or repeated angioplasty ) in 80.5 percent of the patients in the stent group and 76.2 percent of those in the angioplasty group ( P = 0.16 ) . Revascularization of the original target lesion because of recurrent myocardial ischemia was performed less frequently in the stent group than in the angioplasty group ( 10.2 percent vs. 15.4 percent , P = 0.06 ) . CONCLUSIONS In selected patients , placement of an intracoronary stent , as compared with balloon angioplasty , results in an improved rate of procedural success , a lower rate of angiographically detected restenosis , a similar rate of clinical events after six months , and a less frequent need for revascularization of the original coronary lesion BACKGROUND Balloon-exp and able coronary-artery stents were developed to prevent coronary restenosis after coronary angioplasty . These devices hold coronary vessels open at sites that have been dilated . However , it is unknown whether stenting improves long-term angiographic and clinical outcomes as compared with st and ard balloon angioplasty . METHODS A total of 520 patients with stable angina and a single coronary-artery lesion were r and omly assigned to either stent implantation ( 262 patients ) or st and ard balloon angioplasty ( 258 patients ) . The primary clinical end points were death , the occurrence of a cerebrovascular accident , myocardial infa rct ion , the need for coronary-artery bypass surgery , or a second percutaneous intervention involving the previously treated lesion , either at the time of the initial procedure or during the subsequent seven months . The primary angiographic end point was the minimal luminal diameter at follow-up , as determined by quantitative coronary angiography . RESULTS After exclusions , 52 patients in the stent group ( 20 percent ) and 76 patients in the angioplasty group ( 30 percent ) reached a primary clinical end point ( relative risk , 0.68 ; 95 percent confidence interval , 0.50 to 0.92 ; P = 0.02 ) . The difference in clinical -event rates was explained mainly by a reduced need for a second coronary angioplasty in the stent group ( relative risk , 0.58 ; 95 percent confidence interval , 0.40 to 0.85 ; P = 0.005 ) . The mean ( + /- SD ) minimal luminal diameters immediately after the procedure were 2.48 + /- 0.39 mm in the stent group and 2.05 + /- 0.33 mm in the angioplasty group ; at follow-up , the diameters were 1.82 + /- 0.64 mm in the stent group and 1.73 + /- 0.55 mm in the angioplasty group ( P = 0. 
    Output:
    
MAIN OUTCOME MEASURES The primary outcome measure was survival free from cardiac-related events .
There were no important differences between MIDCAB and PTCA with respect to angina symptoms or disease-specific or generic quality of life .
The study found no evidence that MIDCAB was more effective than PTCA .
The procedure costs of MIDCAB were observed to be considerably higher than those of PTCA .
Given these findings , it is unlikely that MIDCAB represents a cost-effective use of re sources in the reference population .
Recent advances in cardiac surgery mean that surgeons now tend to carry out off-pump bypass grafting via a sternotomy instead of MIDCAB .
At the same time , cardiologists are treating more patients with multi-vessel disease by PTCA .