***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 In patients with ST-segment elevation myocardial infa rct ion ( STEMI ) , delay between contact with the health care system and initiation of reperfusion therapy ( system delay ) is associated with mortality , but data on the associated risk for congestive heart failure ( CHF ) among survivors are limited . OBJECTIVE To evaluate the association between system delay and the risk for readmissions or outpatient contacts due to CHF after  primary percutaneous coronary intervention ( PPCI ) in patients with STEMI . DESIGN Historical follow-up study using population -based medical registries . SETTING Western Denmark . PATIENTS Patients with STEMI who were transported by emergency medical service from 1 January 1999 to 7 February 2010 and treated with PPCI within 12 hours of symptom onset and who had a system delay of 6 hours or less ( n = 7952 ) . The median duration of follow-up was 3.1 years . MEASUREMENTS Cumulative incidence of readmissions or outpatient contacts due to CHF was determined by using competing-risk regression analysis , with death as the competing risk . Crude and adjusted cause-specific hazard ratios for readmissions or outpatient contacts due to CHF were determined for system delay and other covariates . RESULTS System delays of 60 minutes or less ( n = 451 ) , 61 to 120 minutes ( n = 3457 ) , 121 to 180 minutes ( n = 2655 ) , and 181 to 360 minutes ( n = 1389 ) corresponded with long-term risks for readmissions or outpatient contacts due to CHF of 10.1 % , 10.6 % , 12.3 % , and 14.1 % , respectively ( P < 0.001 ) . In multivariable analysis ,  system delay was an independent predictor of readmissions or outpatient contacts due to CHF ( adjusted hazard ratio per hour increase in delay , 1.10 [ 95 % CI , 1.02 to 1.17 ] ) . LIMITATION In any nonr and omized study , there are risks for selection bias and residual confounding . CONCLUSION In patients with STEMI , shorter delay to PPCI is associated with lower risk for readmissions or outpatient contacts due to CHF during follow-up Background In patients with ST-elevation myocardial infa rct ion ( STEMI )  reperfusion therapy should be initiated as soon as possible . This study evaluated whether use of a helicopter for transportation of patients is associated with earlier initiation of reperfusion therapy .  Material and methods A prospect i ve study was conducted , including patients with STEMI and symptom duration less than 12 hours , who had primary percutaneous coronary intervention ( PPCI ) performed at Aarhus University Hospital in Skejby . Patients with a health care system delay ( time from emergency call to first coronary intervention ) of more than 360 minutes were excluded . The study period ran from 1.1.2011 until 31.12.2011 . A Western Denmark Helicopter Emergency Medical Service ( HEMS ) project was initiated 1.6.2011 for transportation of patients with time-critical illnesses , including STEMI . Results The study population comprised 398 patients , of whom 376 were transported by ambulance Emergency Medical Service ( EMS ) and 22 by HEMS . Field-triage directly to the PCI-center was used in 338 of patients . The median system delay was 94 minutes among those field-triaged , and 168 minutes among those initially admitted to a local hospital . Patients transported by EMS and field-triaged were stratified into four groups according to transport distance from the scene of event to the PCI-center : ≤25 km . , 26–50 km . , 51–75 km . and > 75 km . For these groups , the median system delay was 78 , 89 , 99 , and 141 minutes . Among patients transported by HEMS and field-triaged the estimated median transport distance by ground transportation was 115 km , and the observed system delay was 107 minutes . Based on second order polynomial regression , it was estimated that patients with a transport distance of > 60 km to the PCI-center may benefit from helicopter transportation , and that transportation by helicopter is associated with a system delay of less than 120 minutes even at a transport distance up to 150 km . Conclusion The present study indicates that use of a helicopter should be considered for field-triage of patients with STEMI to the PCI-center in case of long transportation . Such a strategy may ensure that patients living up to 150 km . from the PCI-center can be treated within 120 minutes of emergency call BACKGROUND The clinical effect of routine intracoronary thrombus aspiration before primary percutaneous coronary intervention ( PCI ) in patients with ST-segment elevation myocardial infa rct ion ( STEMI ) is uncertain . We aim ed to evaluate whether thrombus aspiration reduces mortality . METHODS We conducted a multicenter , prospect i ve , r and omized , controlled , open-label clinical trial , with enrollment of patients from the national comprehensive Swedish Coronary Angiography and Angioplasty Registry ( SCAAR ) and end points evaluated through national registries . A total of 7244 patients with STEMI undergoing PCI were r and omly assigned to manual thrombus aspiration followed by PCI or to PCI only . The primary end point was all-cause mortality at 30 days . RESULTS No patients were lost to follow-up . Death from any cause occurred in 2.8 % of the patients in the thrombus-aspiration group ( 103 of 3621 ) , as compared with 3.0 % in the PCI-only group ( 110 of 3623 ) ( hazard ratio , 0.94 ; 95 % confidence interval [ CI ] , 0.72 to 1.22 ; P=0.63 ) . The rates of hospitalization for recurrent myocardial infa rct ion at 30 days were 0.5 % and 0.9 % in the two groups , respectively ( hazard ratio , 0.61 ; 95 % CI , 0.34 to 1.07 ; P=0.09 ) , and the rates of stent thrombosis were 0.2 % and 0.5 % , respectively ( hazard ratio , 0.47 ; 95 % CI , 0.20 to 1.02 ; P=0.06 ) . There were no significant differences between the groups with respect to the rate of stroke or neurologic complications at the time of discharge ( P=0.87 ) . The results were consistent across all major prespecified subgroups , including subgroups defined according to thrombus burden and coronary flow before PCI . CONCLUSIONS Routine thrombus aspiration before PCI as compared with PCI alone did not reduce 30-day mortality  among patients with STEMI . ( Funded by the Swedish Research Council and others ; Clinical Trials.gov number , NCT01093404 . ) BACKGROUND Cardiac arrest with widespread cerebral ischemia frequently leads to severe neurologic impairment . We studied whether mild systemic hypothermia increases the rate of neurologic recovery after resuscitation from cardiac arrest due to ventricular fibrillation . METHODS In this multicenter trial with blinded assessment of the outcome , patients who had been resuscitated after cardiac arrest due to ventricular fibrillation were r and omly assigned to undergo  therapeutic hypothermia ( target temperature , 32 degrees C to 34 degrees C , measured in the bladder ) over a period of 24 hours or to receive st and ard treatment with normothermia . The primary end point was a favorable neurologic outcome within six months after cardiac arrest ; secondary end points were mortality within six months and the rate of complications within seven days . RESULTS Seventy-five of the 136 patients in the hypothermia group for whom data were available ( 55 percent ) had a favorable neurologic outcome ( cerebral-performance category , 1 [ good recovery ] or 2 [ moderate disability ] ) , as compared with 54 of 137 ( 39 percent ) in the normothermia group ( risk ratio , 1.40 ; 95 percent confidence interval , 1.08 to 1.81 ) . Mortality at six months was 41 percent in the hypothermia group ( 56 of 137 patients died ) , as compared with 55 percent in the normothermia group ( 76 of 138 patients ; risk ratio , 0.74 ; 95 percent confidence interval , 0.58 to 0.95 ) . The complication rate did not differ significantly between the two groups . CONCLUSIONS In patients who have been successfully resuscitated after cardiac arrest due to ventricular fibrillation , therapeutic mild hypothermia increased the rate of a favorable neurologic outcome and reduced mortality CONTEXT Thrombus embolization during percutaneous coronary intervention ( PCI ) in ST-segment elevation myocardial infa rct ion ( STEMI ) is common and results in suboptimal myocardial perfusion and increased infa rct size . Two strategies proposed to reduce distal embolization and improve outcomes after primary PCI are bolus intracoronary abciximab and manual aspiration thrombectomy . OBJECTIVE To determine whether bolus intracoronary abciximab , manual aspiration thrombectomy , or both reduce infa rct size in high-risk patients with STEMI . DESIGN , SETTING , AND PATIENTS Between November 28 , 2009 , and December 2 , 2011 , 452 patients presenting at 37 sites in 6 countries within 4 hours of STEMI due to proximal or mid left anterior descending artery occlusion undergoing primary PCI with bivalirudin anticoagulation  were r and omized in an open-label , 2 x 2 factorial design to bolus intracoronary abciximab delivered locally at the infa rct lesion site vs no abciximab and to manual aspiration thrombectomy vs no thrombectomy . INTERVENTIONS A 0.25-mg/kg bolus of abciximab was administered at the site of the infa rct lesion via a local drug delivery catheter . Manual aspiration thrombectomy was performed with a 6 F aspiration catheter . MAIN OUTCOME MEASURES Primary end point : infa rct size ( percentage of total left ventricular mass ) at 30 days assessed by cardiac magnetic resonance imaging ( cMRI ) in the abciximab vs no abciximab groups ( pooled across the aspiration r and omization ) ; major secondary end point : 30-day infa rct size in the aspiration vs no aspiration groups ( pooled across the abciximab r and omization ) . RESULTS Evaluable cMRI results at 30 days were present in 181 and 172 patients r and omized to intracoronary abciximab vs no abciximab , respectively , and in 174 and 179 patients r and omized to manual aspiration vs no aspiration , respectively . Patients r and omized to intracoronary abciximab compared with no abciximab had a significant reduction in 30-day infa rct size ( median , 15.1 % ; interquartile range [ IQR ] , 6.8%-22.7 % ; n = 181 , vs 17.9 % [ IQR , 10.3%-25.4 % ] ; n = 172 ; P = .03 ) . Patients r and omized to intracoronary abciximab also had a significant reduction in absolute infa rct mass ( median , 18.7 g [ IQR , 7.4 - 31.3 g ] ; n = 184 , vs 24.0 g [ IQR , 12.1 - 34.2 g ] ; n = 175 ; P = .03 ) but not abnormal wall motion score ( median , 7.0 [ IQR , 2.0 - 10.0 ] ; n = 188 , vs 8.0 [ IQR , 3.0 - 10.0 ] ; n = 184 ; P = .08 ) . Patients r and omized to aspiration thrombectomy vs no aspiration had no significant difference in infa rct size at 30 days ( median , 17.0 % [ IQR , 9.0%-22.8 % ] ; n = 174 , vs 17.3 % [ IQR , 7.1%-25.5 % ] ; n = 179 ; P = .51 ) , absolute infa rct mass ( median , 20.3 g [ IQR , 9.7 - 31.7 g ] ; n = 178 , vs 21.0 g [ IQR , 9.1 - 34.1 g ] ; n = 181 ; P = .36 ) , or abnormal wall motion score ( median , 7.5 [ IQR , 2.0 - 10.0 ] ; n = 186 , vs 7.5 [ IQR , 2.0 - 10.0 ] ; n = 186 ; P = .89 ) . CONCLUSION In patients with large anterior STEMI presenting early after symptom onset and undergoing primary PCI with bivalirudin anticoagulation , infa rct size at 30 days was significantly reduced by bolus intracoronary abciximab delivered to the infa rct lesion site but not by manual aspiration thrombectomy . TRIAL REGISTRATION clinical trials.gov Identifier : 
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The biggest survival benefits have undoubtedly been achieved after the advent of reperfusion strategies .