***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: OBJECTIVES The purpose of this r and omized study was to compare sirolimus-eluting stenting with coronary artery bypass grafting ( CABG ) for patients with unprotected left main ( ULM ) coronary artery disease . BACKGROUND CABG is considered the st and ard of care for treatment of ULM . Improvements in percutaneous coronary intervention ( PCI ) with use of drug-eluting stents might lead to similar results . The effectiveness of drug-eluting stenting versus surgery has not been established in a r and omized trial . METHODS In this prospect i ve , multicenter , r and omized trial , 201 patients with ULM disease were r and omly assigned to undergo sirolimus-eluting stenting ( n = 100 ) or CABG using predominantly arterial grafts ( n = 101 ) . The primary clinical end point was noninferiority in freedom from major adverse cardiac events , such as cardiac death , myocardial infa rct ion , and the need for target vessel revascularization within 12 months . RESULTS The combined primary end point was reached in 13.9 % of patients after surgery , as opposed to 19.0 % after PCI ( p = 0.19 for noninferiority ) . The combined rates for death and myocardial infa rct ion were comparable ( surgery , 7.9 % vs. stenting , 5.0 % ; noninferiority p < 0.001 ) , but stenting was inferior to surgery for repeat revascularization ( 5.9 % vs. 14.0 % ; noninferiority p = 0.35 ) . Perioperative complications including 2 strokes were higher after surgery ( 4 % vs. 30 % ; p < 0.001 ) . Freedom from angina was similar between groups ( p = 0.33 ) . CONCLUSIONS In patients with ULM stenosis , PCI with sirolimus-eluting stents did not show noninferiority [ corrected ] to CABG at 12-month follow-up with respect to freedom from major adverse cardiac events , which is mainly influenced by repeated revascularization , whereas for hard endpoints , [ corrected ] PCI results are favorable . A longer follow-up is warranted . [ corrected Background —Percutaneous coronary revascularization ( PCI ) has been increasingly applied to unprotected left main trunk ( LMT ) lesions , with varied long-term success . This study attempts to define the predictors of outcome in this population . Methods and Results —Two hundred seventy-nine consecutive patients who had LMT PCI at 1 of 25 sites between 1993 and 1998 were studied . Forty-six percent of these patients were deemed inoperable or at high surgical risk . Thirty-eight patients ( 13.7 % ) died in hospital , and the rest were followed up for a mean of 19 months . The 1-year incidence was 24.2 % for all-cause mortality , 20.2 % for cardiac mortality , 9.8 % for myocardial infa rct ion , and 9.4 % for CABG . Independent correlates of all-cause mortality were left ventricular ejection fraction ≤30 % , mitral regurgitation grade 3 or 4 , presentation with myocardial infa rct ion and shock , creatinine ≥2.0 mg/dL , and severe lesion calcification . For the 32 % of patients < 65 years old with left ventricular ejection fraction > 30 % and without shock , the prevalence of these adverse risk factors was low . No periprocedural deaths were observed in this low-risk subset , and the 1-year mortality was only 3.4 % . Conclusions — Patients undergoing unprotected LMT PCI have frequent serious comorbidities and consequently have high event rates . PCI may be an alternative to CABG for a select proportion of elective patients and may also be appropriate for highly symptomatic inoperable patients . Meticulous follow-up of hospital survivors is required because of the rather high mortality during the first few months after treatment BACKGROUND Percutaneous coronary intervention ( PCI ) is increasingly used to treat unprotected left main coronary artery stenosis , although coronary-artery bypass grafting ( CABG ) has been considered to be the treatment of choice . METHODS We r and omly assigned patients with unprotected left main coronary artery stenosis to undergo CABG ( 300 patients ) or PCI with sirolimus-eluting stents ( 300 patients ) . Using a wide margin for noninferiority , we compared the groups with respect to the primary composite end point of major adverse cardiac or cerebrovascular events ( death from any cause , myocardial infa rct ion , stroke , or ischemia-driven target-vessel revascularization ) at 1 year . Event rates at 2 years were also compared between the two groups . RESULTS The primary end point occurred in 26 patients assigned to PCI as compared with 20 patients assigned to CABG ( cumulative event rate , 8.7 % vs. 6.7 % ; absolute risk difference , 2.0 percentage points ; 95 % confidence interval [ CI ] , -1.6 to 5.6 ; P=0.01 for noninferiority ) . By 2 years , the primary end point had occurred in 36 patients in the PCI group as compared with 24 in the CABG group ( cumulative event rate , 12.2 % vs. 8.1 % ; hazard ratio with PCI , 1.50 ; 95 % CI , 0.90 to 2.52 ; P=0.12 ) . The composite rate of death , myocardial infa rct ion , or stroke at 2 years occurred in 13 and 14 patients in the two groups , respectively ( cumulative event rate , 4.4 % and 4.7 % , respectively ; hazard ratio , 0.92 ; 95 % CI , 0.43 to 1.96 ; P=0.83 ) . Ischemia-driven target-vessel revascularization occurred in 26 patients in the PCI group as compared with 12 patients in the CABG group ( cumulative event rate , 9.0 % vs. 4.2 % ; hazard ratio , 2.18 ; 95 % CI , 1.10 to 4.32 ; P=0.02 ) . CONCLUSIONS In this r and omized trial involving patients with unprotected left main coronary artery stenosis , PCI with sirolimus-eluting stents was shown to be noninferior to CABG with respect to major adverse cardiac or cerebrovascular events . However , the noninferiority margin was wide , and the results can not be considered clinical ly directive . ( Funded by the Cardiovascular Research Foundation , Seoul , Korea , and others ; PRECOMBAT Clinical Trials.gov number , NCT00422968 . ) The 3 year cumulative survival rate of 1,492 patients with left main coronary artery disease ( 50 percent or greater stenosis of luminal diameter ) enrolled in the Collaborative Study in Coronary Artery Surgery ( CASS ) was 91 percent for the surgical group and 69 percent for patients treated medically ( p less than 0.0001 ) . Mortality was significantly greater in patients with impaired left ventricular function . The difference between medical and surgical therapy was significant for patients who had normal , moderately abnormal and severely impaired left ventricular function and for patients with stenosis of the left main coronary artery of 50 to 59 , 60 to 69 , 70 to 79 and 80 percent or greater . Aortocoronary bypass surgery did not significantly improve survival in patient subgroups who had ( 1 ) a nonstenotic dominant right or balanced coronary circulation , ( 2 ) a stenotic dominant right coronary artery and normal left ventricular function , and ( 3 ) left main coronary stenosis of 50 to 59 percent and normal or mildly abnormal left ventricular function . The Cox proportional hazards model was used to select baseline variables that were independent predictors of long-time mortality . The model selected left ventricular score , age , congestive heart failure score , hypertension , percent left main coronary arterial stenosis and coronary arterial dominance as the baseline variables most predictive of long-term survival . A clinical and angiographic prognostic risk index developed from these six baseline variables showed significantly improved survival for the surgical cohort in each of four risk categories . In the best and worst risk category , the 3 year survival rate was 97 and 82 percent , respectively , for the surgical group and 85 and 34 percent , respectively , for the medical group ( p less than or equal to 0.0002 ) . The data from this observational study show that coronary bypass surgery prolongs life in most patients with left main coronary artery disease , particularly those who have severe narrowing of the left main coronary artery or impaired left ventricular function . The results permit a better underst and ing of the natural history of left main coronary artery disease and permit a more accurate estimate of long-term survival for individual patients through the use of a clinical -angiographic risk index Background — Current guidelines recommend coronary artery bypass graft surgery ( CABG ) when treating significant de novo left main coronary artery ( LM ) stenosis ; however , percutaneous coronary intervention ( PCI ) has a class IIa indication for unprotected LM disease in selected patients . This analysis compares 5-year clinical outcomes in  PCI- and CABG-treated LM patients in the Synergy Between PCI With Taxus and Cardiac Surgery ( SYNTAX ) trial , the largest trial in this group to date . Methods and Results — The SYNTAX trial r and omly assigned 1800 patients with LM or 3-vessel disease to receive either PCI ( with TAXUS Express paclitaxel-eluting stents ) or CABG .  The unprotected LM cohort ( N=705 ) was predefined and powered . Major adverse cardiac and cerebrovascular event rates at 5 years was 36.9 % in PCI patients and 31.0 % in CABG patients ( hazard ratio , 1.23 [ 95 % confidence interval , 0.95–1.59 ] ; P=0.12 ) . Mortality rate was 12.8 % and 14.6 % in PCI and CABG patients , respectively ( hazard ratio , 0.88 [ 95 % confidence interval , 0.58–1.32 ] ; P=0.53 ) . Stroke was significantly increased in the CABG group ( PCI 1.5 % versus CABG 4.3 % ; hazard ratio , 0.33 [ 95 % confidence interval , 0.12–0.92 ] ; P=0.03 ) and repeat revascularization in the PCI arm ( 26.7 % versus 15.5 % ; hazard ratio , 1.82 [ 95 % confidence interval , 1.28–2.57 ] ; P<0.01 ) . Major adverse cardiac and cerebrovascular events were similar between arms in patients with low/intermediate SYNTAX scores but significantly increased in PCI patients with high scores ( ≥33 ) . Conclusions — At 5 years , no difference in overall major adverse cardiac and cerebrovascular events was found between treatment groups . PCI-treated patients had a lower stroke but a higher revascularization rate versus CABG . These results suggest that both treatments are valid options for LM patients . The extent of disease should accounted for when choosing between surgery and PCI , because patients with high SYNTAX scores seem to benefit more from surgery compared with those in the lower tertiles . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00114972 BACKGROUND Currently available r and omized data on the comparison between percutaneous coronary intervention ( PCI ) and coronary artery bypass graft ( CABG ) for the treatment of unprotected left main coronary disease ( LMD ) lacks statistical power due to low numbers of patients enrolled . OBJECTIVES This study assessed long-term outcomes of PCI and CABG for the treatment of LMD in specific subgroups according to disease anatomic complexity . METHODS We conducted a pooled analysis of individual patient-level data of the LMD patients included in the PRECOMBAT ( Bypass Surgery Versus Angioplasty Using Sirolimus-Eluting Stent in Patients With Left Main Coronary Artery Disease ) and SYNTAX ( Synergy Between PCI With TAXUS and Cardiac Surgery ) trials . Incidences of major adverse cardiac events were assessed at 5 years follow-up . RESULTS Study population comprised 1,305 patients . The incidence of major adverse cardiac and cerebrovascular events at 5 years was 28.3 % in the PCI group and 23.0 % in the CABG group ( hazard ratio [ HR ] : 1.23 ; 95 % confidence interval [ CI ] : 1.01 to 1.55 ; p = 0.045 ) . This difference is mainly driven by a higher rate of repeat revascularization associated with PCI ( HR : 1.85 ; 95 % CI : 1.38 to 2.47 ; p < 0.001 ) . The 2 strategies showed similar rates of the safety composite endpoint of death , myocardial infa rct ion , or stroke ( p = 0.45 ) . In patients with isolated LM or LM + 1-vessel disease , PCI was associated with a 60 % reduction in all-cause mortality ( HR : 0.40 ; 95 % CI : 0.20 to 0.83 ; p = 0. 
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However , stroke risk was significantly lower in the PCI group .
Subgroup analysis of studies with ≥5 years follow-up showed similar outcomes except for the noninferiority outcome of MACCE in the PCI arm .
However , the PCI  group proved good safety profile after a minimum of 30-day follow-up with lower MACCE outcome .
Nonetheless , it has been proven safe during short-term follow-up