***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 —Creatine kinase (CK)-MB elevation after  percutaneous coronary intervention ( PCI )  has been associated with subsequent cardiac death . The patients at risk , the timing of risk , and potential treatment implication s are uncertain . Methods and Results —Eight thous and , four hundred nine consecutive non– acute myocardial infa rct ion patients with successful PCI and no emergency surgery or Q-wave myocardial infa rct ion were followed for 38±25 months ; 1446 ( 17.2 % ) had post-PCI CK-MB above normal on routine ascertainment . Patients were prospect ively stratified into those with CK-MB 1 to 5 × or CK-MB > 5 × normal . No patient with CK-MB 1 to 5 × normal died during the first week after PCI , and excess risk of early death for patients with CK-MB elevation occurred primarily in the first 3 to 4 months . The actuarial 4-month risk of death was 8.9 % , 1.9 % , and 1.2 % for patients with CK-MB > 5 × , CK-MB 1 to 5 × , and CK-MB ≤1 × normal ( P < 0.001 ) . Death within 4 months was independently correlated with the degree of CK-MB elevation , creatinine ≥2 mg% , post-PCI C-reactive protein , low ejection fraction , age , and congestive heart failure class ( P < 0.01 for all ) . In a matched subset analysis , incomplete revascularization ( P < 0.001 ) , congestive heart failure class ( P = 0.005 ) , and no statin treatment at hospital discharge ( P = 0.009 ) were associated with death . Conclusions — Patients with CK-MB elevation after PCI are at excess risk of death for 3 to 4 months , although prolonging hospitalization for CK-MB 1 to 5 × is unlikely to modify risk . CK-MB > 5 × normal , incomplete revascularization , elevated C-reactive protein , heart failure , the elderly , and hospital discharge without on statin therapy increases risk . Several of these factors suggest that inflammation may play a part in the excess risk of death Background The clinical significance of myocardial infa rct ion related to treatment with percutaneous coronary intervention ( PCI ) has been subject of great discussion . This subject has been studied for many years using different definitions of peri-procedural myocardial infa rct ion and different biomarkers , the results have varied greatly depending on methods and time of the study . This study was to determine the incidence and prognostic significance of elevated cardiac biomarkers after elective PCI in patients with stable angina pectoris using the current cut-off set by the Third Universal Definition of Myocardial Infa rct ion and current biomarkers . Methods We performed a historical prospect i ve follow-up study of all patients with stable angina pectoris who underwent elective PCI at Aalborg University Hospital , Denmark from January 1st 2000 to December 31st 2012 . We stratified patients according to peak post-PCI troponin T ( cTnT ) and Creatine Kinase MB mass ( CK-MBmass ) . Results Follow-up for time to all-cause mortality was mean 5.8 years and total 15,891 years and mean 3.7 years and total 10,160 years for the combined endpoint of all-cause mortality and new onset heart failure . During the follow up period 399 of 2760 patients died ( 14.5 % ) and 1095 ( 39.7 % ) suffered the combined endpoint . Post-PCI concentration of cTnT and CK-MBmass was elevated above the defined cut-off in 419 patients ( 15.2 % ) and 113 patients ( 4.1 % ) respectively . There was no statistically significant difference between the groups in stratified analysis of the hazard rates by time regarding all-cause mortality for cTnT nor CK-MBmass . Regarding the combined endpoint the results were ambiguous . The results were unchanged in multivariable analyses that included age and gender . Conclusion The incidence of elevated biomarkers after elective PCI in patients with stable angina pectoris using the defined cut-off ( > 5 x URL ) was 15.2 % using cTnT and 4.1 % using CK-MBmass . The independent prognostic value for both cardiac biomarkers of any cut-off showed no statistical significance for all-cause mortality , whereas the combined endpoint ( all-cause mortality or new-onset heart failure ) were ambiguous in both short- and long-term follow-up OBJECTIVES We examined the relations of elevated creatine kinase ( CK ) and its myocardial b and isoenzyme ( CK-MB ) to clinical outcomes after percutaneous coronary intervention ( PCI ) in patients enrolled in Integrilin ( eptifibatide ) to Minimize Platelet Aggregation and Coronary Thrombosis-II ( trial ) ( IMPACT-II ) , a trial of the platelet glycoprotein IIb/IIIa inhibitor eptifibatide . BACKGROUND Elevation of cardiac enzymes often occurs after PCI , but its clinical implication s are uncertain . METHODS Patients undergoing elective , scheduled PCI for any indication were analyzed . Parallel analyses investigated CK ( n=3,535 ) and CK-MB ( n=2,341 ) levels after PCI ( within 4 to 20 h ) . Clinical outcomes at 30 days and 6 months were stratified by postprocedure CK and CK-MB ( multiple of the site 's upper normal limit ) . RESULTS Overall , 1,779 patients ( 76 % ) had no CK-MB elevation ; CK-MB levels were elevated to 1 to 3 times the upper normal limit in 323 patients ( 13.8 % ) , to 3 to 5 times normal in 84 ( 3.6 % ) , to 5 to 10 times normal in 86 ( 3.7 % ) , and to > 10 times normal in 69 patients ( 2.9 % ) . Elevated CK-MB was associated with an increased risk of death , reinfa rct ion , or emergency revascularization at 30 days , and of death , reinfa rct ion , or surgical revascularization at 6 months . Elevated total CK to above three times normal was less frequent , but its prognostic significance paralleled that seen for CK-MB . The degree of risk correlated with the rise in CK or CK-MB , even for patients with successful procedures not complicated by abrupt closure . CONCLUSIONS Elevations in cardiac enzymes , including small increases ( between one and three times normal ) often not considered an infa rct ion , are associated with an increased risk for short-term adverse clinical outcomes after successful or unsuccessful PCI Background — Creatine kinase-MB ( CK-MB ) elevation after  percutaneous coronary intervention ( PCI )  has been associated with increased risk for mortality . Although most studies have defined periprocedural myocardial infa rct ion ( pMI ) as an elevation in CK-MB > 3 × upper limit of normal ( ULN ) , use of different CK-MB assays and variation in site-specific definitions of the ULN may limit the value of such relative thresholds . Methods and Results — We used data from the multicenter Evaluation of Drug-Eluting Stents and Ischemic Events ( EVENT ) registry to examine the impact of variations in site-specific thresholds for CK-MB elevation on the incidence of pMI as well as the relationship between absolute peak levels of CK-MB after PCI and 1-year mortality . The study cohort consisted of 6347 patients who underwent nonemergent PCI and had normal CK-MB at baseline . Across the 59 study centers , the ULN for CK-MB ranged from 2.6 to 10.4 ng/mL ( median , 5.0 ng/mL ) , and there was an inverse relationship between the site-specific ULN and the incidence of pMI ( defined as CK-MB elevation > 3 × ULN ) . Although any postprocedure elevation of CK-MB was associated with an adverse prognosis , in categorical analyses , only CK-MB ≥50 ng/mL was independently associated with increased 1-year mortality ( hazard ratio , 4.71 ; 95 % confidence interval , 2.42 to 9.13 ; P<0.001 ) . Spline analysis using peak CK-MB as a continuous variable suggested a grade d , nonlinear relationship with 1-year mortality , with an inflection point at ≈30 ng/mL. Conclusions — Among unselected patients undergoing PCI , there is a grade d relationship between CK-MB elevation after PCI and 1-year mortality that is particularly strong for large CK-MB elevations ( > 30 to 50 ng/mL ) . Future studies that include pMI as a clinical end point should consider using a core laboratory to assess CK-MB ( to ensure consistency ) and raising the threshold for defining pMI above current levels ( to enhance clinical relevance ) Background —Aggressive platelet inhibition is crucial to reduce myocardial injury and early cardiac events after coronary intervention . Although observational data have suggested that pretreatment with a high loading dose of clopidogrel may be more effective than a conventional dose , this hypothesis has never been tested in a r and omized trial . Methods and Results —A total of 255 patients scheduled to undergo percutaneous coronary intervention were r and omized to a 600-mg ( n=126 ) or 300-mg ( n=129 ) loading regimen of clopidogrel given 4 to 8 hours before the procedure . Creatine kinase MB , troponin I , and myoglobin levels were measured at baseline and at 8 and 24 hours after intervention . The primary end point was the 30-day occurrence of death , myocardial infa rct ion ( MI ) , or target vessel revascularization . The primary end point occurred in 4 % of patients in the high loading dose versus 12 % of those in the conventional loading dose group ( P=0.041 ) and was due entirely to periprocedural MI . Peak values of all markers were significantly lower in patients treated with the 600-mg regimen ( P≤0.038 ) . Safety end points were similar in the 2 arms . At multivariable analysis , the high loading regimen was associated with a 50 % risk reduction of MI ( OR 0.48 , 95 % CI 0.15 to 0.97 , P=0.044 ) . An incremental benefit was observed in patients r and omized to the 600-mg dose who were receiving statins , with an 80 % risk reduction . Conclusions —Pretreatment with a 600-mg loading dose of clopidogrel 4 to 8 hours before the procedure is safe and , as compared with the conventional 300-mg dose , significantly reduced periprocedural MI in patients undergoing percutaneous coronary intervention . These results may influence practice patterns with regard to antiplatelet therapy before percutaneous revascularization OBJECTIVES Our aim was to examine the prognostic importance of hemorrhagic and ischemic complications after  percutaneous coronary intervention ( PCI ) in unselected patients . BACKGROUND In r and omized trials of PCI , major bleeding and periprocedural myocardial infa rct ion ( pMI ) have been associated with increased mortality . Whether similar associations exist among un-selected PCI patients is unknown . METHODS We used data from the EVENT ( Evaluation of Drug Eluting Stents and Ischemic Events ) registry-a multicenter registry of unselected patients undergoing PCI-to  examine the association between both in-hospital bleeding and pMI and 1-year mortality . Cardiac enzyme levels were assessed in all patients , and pMI was defined as a peak creatine kinase-MB value > or=3x the upper limit of normal . Post-PCI bleeding was classified by Thrombolysis In Myocardial Infa rct ion criteria . RESULTS After excluding patients with elevated pre-PCI creatine kinase-MB values and ST-segment elevation myocardial infa rct ion at presentation ( n = 1,626 ) , a total of 5,961 patients were available for evaluation .  Rates of post-PCI bleeding and pMI were 3.0 % and 7.1 % , respectively ; 1-year all-cause mortality was 2.8 % . After multivariable adjustment , both post-PCI bleeding ( adjusted hazard ratio [ HR ] : 3.83 , 95 % confidence interval : 2.48 to 5.90 , p < 0.001 ) and pMI ( adjusted HR : 1.84 , 95 % confidence interval : 1.17 to 2.89 , p = 0.009 ) were independently associated with 1-year mortality . Time period-specific analyses demonstrated that the adjusted HR for bleeding was similar for 30-day mortality and mortality between 1 month and 1 year , while the adjusted HR for pMI was greater for 30-day mortality as compared with mortality between 1 month and 1 year . CONCLUSIONS Among unselected PCI patients , both post-PCI bleeding and pMI are independently associated with increased 1-year mortality . Continued efforts to reduce these complications after PCI are warranted Background —Cardiac troponin detected by new-generation , highly sensitive assays predicts clinical outcomes among patients with stable coronary artery disease ( SCAD ) treated medically . The prognostic value of baseline high-sensitivity cardiac troponin T ( hs-cTnT ) elevation in SCAD patients undergoing elective 
    Output:
    
Conclusion The occurrence of periprocedural myocardial infa rct ion after an elective percutaneous coronary intervention in patients with stable angina pectoris is associated with a statistically significant increase in subsequent all-cause mortality and cardiac mortality