***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: OBJECTIVES The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention ( PCI ) guided by fractional flow reserve ( FFR ) in patients with multivessel coronary artery disease ( CAD ) . BACKGROUND In patients with multivessel CAD undergoing PCI , coronary angiography is the st and ard method for guiding stent placement . The FAME ( Fractional Flow Reserve Versus Angiography for Multivessel Evaluation ) study showed that routine FFR in addition to angiography improves outcomes of PCI at 1 year . It is unknown if these favorable results are maintained at 2 years of follow-up . METHODS At 20 U.S. and European medical centers , 1,005 patients with multivessel CAD were r and omly assigned to PCI with drug-eluting stents guided by angiography alone or guided by FFR measurements . Before r and omization , lesions requiring PCI were identified based on their angiographic appearance . Patients r and omized to angiography-guided PCI underwent stenting of all indicated lesions , whereas those r and omized to FFR-guided PCI underwent stenting of indicated lesions only if the FFR was < or=0.80 . RESULTS The number of indicated lesions was 2.7+/-0.9 in the angiography-guided group and 2.8+/-1.0 in the FFR-guided group ( p=0.34 ) . The number of stents used was 2.7+/-1.2 and 1.9+/-1.3 , respectively ( p<0.001 ) . The 2-year rates of mortality or myocardial infa rct ion were 12.9 % in the angiography-guided group and 8.4 % in the FFR-guided group ( p=0.02 ) . Rates of PCI or coronary artery bypass surgery were 12.7 % and 10.6 % , respectively ( p=0.30 ) . Combined rates of death , nonfatal myocardial infa rct ion , and revascularization were 22.4 % and 17.9 % , respectively ( p=0.08 ) . For lesions deferred on the basis of FFR>0.80 , the rate of myocardial infa rct ion was 0.2 % and the rate of revascularization was 3.2 % after 2 years . CONCLUSIONS Routine measurement of FFR in patients with multivessel CAD undergoing PCI with drug-eluting stents significantly reduces mortality and myocardial infa rct ion at 2 years when compared with st and ard angiography-guided PCI . ( Fractional Flow Reserve Versus Angiography for Multivessel Evaluation [ FAME ] ; NCT00267774 ) Background Regadenoson is a selective A2A adenosine receptor agonist and vasodilator used to increase the heterogeneity of distribution of coronary blood flow during myocardial perfusion imaging . This study characterized the dose dependence of regadenoson-induced coronary hyperemia . Methods and Results An open-label , dose-escalation study of regadenoson ( 10–500μg , rapid intravenous bolus ) was performed in 34 subjects ; in 4 additional subjects , the effect of aminophylline to reverse the response to regadenoson was determined . Intracoronary peak blood flow velocity in either the left anterior descending or left circumflex artery was measured by continuous Doppler , signal recording , heart rate , central aortic blood pressure , and adverse effects were recorded . Regadenoson  increased peak blood flow velocity by up to 3.4-fold in a dose-dependent manner . The mean duration of the increase in flow velocity of 2.5-fold or greater caused by 400 to 500 μg of regadenoson was 2.3 to 2.4 minutes . Regadenoson ( 400–500 μg ) increased heart rate by up to 21±6 beats/min and decreased systolic blood pressure ( −5±8 mm Hg to −24±16 mm Hg ) and diastolic blood pressure ( −8±4 mm Hg to −15±14 mm Hg ) . Aminophylline ( 100 mg ) attenuated the increase in peak flow velocity but not tachycardia caused by 400 μg of regadenoson . Conclusion The results of this study demonstrate the utility of regadenoson as a coronary vasodilator for myocardial perfusion imaging OBJECTIVES The purpose of this study was to investigate the appropriateness of stenting a functionally nonsignificant stenosis . BACKGROUND Percutaneous coronary intervention ( PCI ) of an intermediate stenosis without evidence of ischemia is often performed , but its benefit is unproven . Coronary pressure-derived fractional flow reserve ( FFR ) is an invasive index used to identify a stenosis responsible for reversible ischemia . METHODS In 325 patients scheduled for PCI of an intermediate stenosis , FFR was measured just before the planned intervention . If FFR was > or = 0.75 , patients were r and omly assigned to deferral ( Defer group ; n = 91 ) or performance ( Perform group ; n = 90 ) of PCI . If FFR was < 0.75 , PCI was performed as planned ( Reference group ; n = 144 ) . Clinical follow-up was 5 years . RESULTS There were no differences in baseline clinical characteristics between the 3 groups . Complete follow-up was obtained in 98 % of the patients . Event-free survival was not different between the Defer and Perform groups ( 80 % and 73 % , respectively ; p = 0.52 ) , but was significantly worse in the Reference group ( 63 % ; p = 0.03 ) . The composite rate of cardiac death and acute myocardial infa rct ion in the Defer , Perform , and Reference groups was 3.3 % , 7.9 % , and 15.7 % , respectively ( p = 0.21 for Defer vs. Perform group ; p = 0.003 for the Reference vs. both other groups ) . The percentage of patients free from chest pain at follow-up was not different between the Defer and Perform groups . CONCLUSIONS Five-year outcome after deferral of PCI of an intermediate coronary stenosis based on FFR > /=0.75 is excellent . The risk of cardiac death or myocardial infa rct ion related to this stenosis is < 1 % per year and not decreased by stenting Background Earlier phase 1 and 2 studies have shown that regadenoson has desirable features as a stress agent for myocardial perfusion imaging . Methods and Results This multicenter , double-blinded phase 3 trial involved 784 patients at 54 sites . Each patient underwent 2 sets of gated single photon emission computed tomography myocardial perfusion imaging studies : an initial qualifying study with adenosine and a subsequent r and omized study with either regadenoson ( 2/3 of patients ) or adenosine . Regadenoson was administered as a rapid bolus ( < 10 seconds ) of 400 μg . The primary endpoint was to demonstrate noninferiority by showing that the difference in the strength of agreement in detecting reversible defects , based on blinded reading , between sequential adenosine-regadenoson images and adenosine-adenosine images , lay above a prespecified noninferiority margin . Other prospect ively defined safety and tolerability comparisons and supporting analyses were also performed . The average agreement rate based on the median of 3 independent blinded readers was 0.63±0.03 for regadenoson-adenosine and 0.64±0.04 for adenosine-adenosine — a 1 % absolute difference with the lower limit of the 95 % confidence interval lying above the prespecified noninferiority margin . Side-by-side interpretation of regadenoson and adenosine images provided comparable results for detecting reversible defects . The peak increase in heart rate was greater with regadenoson than adenosine , but the blood pressure nadir was similar . A summed symptom score of flushing , chest pain , and dyspnea was less with regadenoson than adenosine ( P=.013 ) . Conclusions This phase 3 trial shows that regadenoson provides diagnostic information comparable to a st and ard adenosine infusion . There were no serious drug-related side effects , and regadenoson was better tolerated than adenosine OBJECTIVES To compare the effects of age , gender , body mass index , and diabetes on the safety and efficacy of  regadenoson stress myocardial perfusion imaging , and to assess the noninferiority of regadenoson to adenosine for the detection of reversible myocardial perfusion defects . BACKGROUND Previous reports have shown that a fixed unit bolus of regadenoson is safe and noninferior to adenosine for the detection of reversible perfusion defects by radionuclide imaging . METHODS Using a data base of 2,015 patients , we evaluated the effects of age , gender , body mass index , and diabetes on the safety and efficacy of regadenoson compared to adenosine . RESULTS For detection of ischemia relative to adenosine , noninferiority was demonstrated for all patients ( agreement rate difference 0 % , 95 % CI -6.2 % to + 6.8 % ) . The average agreement rate between adenosine-adenosine and adenosine-regadenoson were 0.62 + /- 0.03 and 0.63 + /- 0.02 . Detection of ischemia was also comparable in specific subgroups . Agreement was less for both agents in women versus men with moderate and large areas of ischemia . Compared to adenosine , regadenoson had a lower combined symptom score and less chest pain , flushing , and throat , neck , or jaw pain , but more headache and gastrointestinal discomfort . This was true in nearly all subgroups . Regadenoson patients reported feeling more comfortable ( 1.7 + /- .02 vs. 1.9 + /- 0.03 , p < 0.001 ) . Based on the overall tolerability score , women felt less comfortable than men with both stress agents . Image quality was rated good or excellent in 92 % for both agents . CONCLUSIONS Regadenoson can be safely administered as a fixed unit bolus and is as efficacious as adenosine in detecting ischemia regardless of age , gender , body mass index , and diabetes . Regadenoson is better tolerated overall and across various subgroups Background . Patients with reactive airways are at risk for adenosine-induced bronchoconstriction , mediated via A2B and /or A3 adenosine receptors . Methods and Results . In this r and omized , double-blind , placebo-controlled crossover trial , we examined the safety of regadenoson , a selective adenosine A2A receptor agonist , in patients with moderate chronic obstructive pulmonary disease ( COPD ) ( n=38 ) and patients with severe COPD ( n=11 ) with a baseline mean forced expiratory volume in 1 second ( FEV1 ) of 1.74±0.50 L and 1.0±0.35 L , respectively , 37 % of whom had dyspnea during activities of daily living . Patients receiving glucocorticoids or oxygen and those with pretreatment wheezing were included . Short-acting bronchodilators were withheld for at least 8 hours before treatment . No differences emerged between regadenoson and placebo on multiple lung function parameters , including repeated FEV1 and forced vital capacity , respiratory rate , pulmonary examinations , and oxygen saturation . The mean maximum decline in FEV1 was 0.11±0.02 L and 0.12±0.02 L ( P=.55 ) in patients after regadenoson and placebo , respectively , and new-onset wheezing was observed in 6 % and 12 % , respectively ( P=.33 ) . No patient required acute treatment with bronchodilators or oxygen . Conclusions . This pilot study showed the overall safety of regadenoson in 49 compromised out patients with clinical ly stable moderate and severe chronic obstructive pulmonary disease AIMS The aim of this study was to compare the hyperaemic effect of a single bolus regadenoson injection to a central venous adenosine infusion for inducing hyperaemia in the measurement of fractional flow reserve ( FFR ) . METHODS AND RESULTS One hundred patients scheduled for FFR measurement were enrolled .  FFR was first measured by IV adenosine ( 140 µg/kg/min ) , thereafter by IV bolus regadenoson injection ( 400 µg ) , followed by another measurement by IV adenosine and bolus injection of regadenoson . The regadenoson injections were r and omised to central or peripheral intravenous . Hyperaemic response and duration of steady state maximum hyperaemia were studied , central versus peripheral venous regadenoson injections were compared , and safety and reproducibility of repeated injections were investigated . Mean age was 66±8 years , 75 % of the patients were male . The target stenosis was located in the LM , LAD , LCX , and RCA in 7 % , 54 % , 20 % and 19 % , respectively . There was no difference in FFR measured by adenosine or by regadenoson ( ΔFFR=0.00±0.01 , r=0.994 , p<0.001 ) . Duration of maximum hyperaemia  after regadenoson was variable ( 10 - 600 s ) . No serious side effects of either drug were observed . CONCLUSIONS Maximum coronary hyperaemia can be achieved easily , rapidly , and safely by one single intravenous bolus of 
    Output:
    
IV regadenoson and IC nitroprusside produce similar pressure-derived FFR measurements compared to IV adenosine and have a favorable side effect profile .
Both can be considered as alternative agents to IV adenosine for FFR measurement .