***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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    Input: BACKGROUND Nephropathy induced by exposure to radiocontrast agents , a possible complication of percutaneous coronary interventions , is associated with significant in-hospital and long-term morbidity and mortality . Patients with preexisting renal failure are at particularly high risk . We investigated the role of hemofiltration , as compared with isotonic-saline hydration , in preventing contrast-agent-induced nephropathy in patients with renal failure . METHODS We studied 114 consecutive patients with chronic renal failure ( serum creatinine concentration , > 2 mg per deciliter [ 176.8 micromol per liter ] ) who were undergoing coronary interventions . We r and omly assigned them to either hemofiltration in an intensive care unit ( ICU ) ( 58 patients , with a mean [ + /-SD ] serum creatinine concentration of 3.0+/-1.0 mg per deciliter [ 265.2+/-88.4 micromol per liter ] ) or isotonic-saline hydration at a rate of 1 ml per kilogram of body weight per hour given in a step-down unit ( 56 patients , with a mean serum creatinine concentration of 3.1+/-1.0 mg per deciliter [ 274.0+/-88.4 micromol per liter ] ) . Hemofiltration ( fluid replacement rate , 1000 ml per hour without weight loss ) and saline hydration were initiated 4 to 8 hours before the coronary intervention and were continued for 18 to 24 hours after the procedure was completed . RESULTS An increase in the serum creatinine concentration of more than 25 percent from the base-line value after the coronary intervention occurred less frequently among the patients in the hemofiltration group than among the control patients ( 5 percent vs. 50 percent , P<0.001 ) . Temporary renal-replacement therapy ( hemodialysis or hemofiltration ) was required in 25 percent of the control patients and in 3 percent of the patients in the hemofiltration group . The rate of in-hospital events was 9 percent in the hemofiltration group and 52 percent in the control group ( P<0.001 ) . In-hospital mortality was 2 percent in the hemofiltration group and 14 percent in the control group ( P=0.02 ) , and the cumulative one-year mortality was 10 percent and 30 percent , respectively ( P=0.01 ) . CONCLUSIONS In patients with chronic renal failure who are undergoing percutaneous coronary interventions , periprocedural hemofiltration given in an ICU setting appears to be effective in preventing the deterioration of renal function due to contrast-agent-induced nephropathy and is associated with improved in-hospital and long-term outcomes The pathophysiology and prevention of contrast media (CM)-induced nephropathy in chronic renal failure ( CRF ) are still ill defined . GFR , RPF , endothelin-1 ( ET-1 ) levels , urinary sodium concentration , and fractional excretion of sodium were measured in CRF patients undergoing water diuresis in basal conditions and 20 to 120 min after an iv bolus of either the high-osmolar CM diatrizoate ( D ) or the low-osmolar CM iopamidol ( I ) .  The two CM induced an immediate and progressive decline of both GFR and RPF in the absence of hypovolemia , more pronounced in D ( -36 % at 120 min ) than after I ( -19 % at 120 min ; P < 0.05 versus D ) . Both CM determined a marked and steady increase of the fractional excretion of sodium . The natriuresis could not be totally ascribed to a CM-induced osmotic diuresis as because the urinary sodium concentration markedly increased . In two further groups of patients receiving D , we studied the effects of pretreatment with a single dose of either captopril or nifedipine . Both drugs , although not preventing the increase of natriuresis , partially antagonized D-induced renal hypoperfusion : GFR and RPF were equally reduced by 20 % in D/captopril and D/nifedipine ( P < 0.05 versus D ) . In unpretreated patients receiving either D or I , plasma ET-1 did not change but urinary levels increased ; these changes were , however , dissociated from those observed in renal hemodynamics . Both plasma and urinary levels of ET-1 did not vary in pretreated groups . The 72-h follow-up evidence d a significant reduction of renal function only in the unpretreated D group . Therefore , the main findings after CM administration in CRF patients are : ( 1 ) an immediate GFR decline proportional to the osmolarity of CM and secondary to the renal hypoperfusion that is neither caused by hypovolemia nor mediated by ET-1 , ( 2 ) an early tubular dysfunction at the level of the proximal nephron , and ( 3 ) a protective effect of single-dose pretreatment with either captopril or nifedipine on D-induced acute and short-term GFR changes Despite myriad improvements in the care of hospitalized patients , a decline in renal function remains a common event . Renal function in 4,622 consecutive patients admitted to the medical and surgical services of an urban tertiary care hospital was followed up prospect ively from the time of admission . Some degree of renal insufficiency developed in 7.2 % of patients . Decreased renal perfusion , medications , surgery , and radiographic contrast media were the most common causes of hospital-acquired renal insufficiency ( HARI ) . The overall mortality rate was 19.4 % and was similar among patients for all causes of renal insufficiency , except sepsis . For patients with a greater than 3.0-mg/dL increase in serum creatinine level , the mortality rate was 37.8 % . As shown by previous investigators , age and preexisting renal insufficiency were risk factors for HARI . Women and blacks had less hospital-acquired renal failure . The increasing acuity of hospital admissions has been accompanied by a greater incidence of acute renal insufficiency in patients admitted to hospitals . There is a trend toward better survival in patients with a severe deterioration in renal function BACKGROUND Although the capability of extracorporeal treatments after administration of contrast media to prevent radiocontrast-induced nephropathy is controversial , haemodialysis is performed in many institutions after radiographic procedures . There are conflicting reports on the efficacy of different dialysers and treatment modalities to remove contrast media . METHODS We compared the contrast medium-removing ability of different extracorporeal treatments in a r and omized trial . Thirty-nine patients on chronic renal-replacement therapy or with chronic renal failure were r and omized to receive  low-flux haemodialysis ( Low-HD , n=10 ) , high-flux haemodialysis ( High-HD , n=10 ) , online haemodiafiltration ( HDF , 10 litre substitution , n=10 ) and online haemofiltration ( HF , 18 litre substitution , n=9 ) after administration of contrast medium during routine radiological procedures . Plasma concentrations of contrast medium ( iopromide or iomeprol ) were measured by energy-dispersive X-ray fluorescence analysis . RESULTS The extraction ratio for contrast media was 0.64+/-0.1 for Low HD ( P<0.05 vs. High-HD and vs. HDF ) , 0.74+/-0.1 for High-HD ( P<0.05 vs. HF ) , 0.81+/-0.1 for HDF ( P<0.05 vs HF ) , and 0.62+/-0.1 for HF . Mean extracorporeal plasma clearances were 82+/-2 for Low-HD ( P<0.05 vs. High-HD and vs HDF ) , 100+/-2 for High-HD , 115+/-4 for HDF ( P<0.05 vs. HF ) , and 86+/-5 ml/min for HF . CONCLUSIONS We conclude that HDF and High-HD remove contrast media more effectively than Low-HD and HF during the time of each treatment session . However , whether this is also true for the overall elimination of contrast media by these different procedures needs to be addressed in future studies , by a precise assessment of the drug time course after the session Objective : Several strategies have been employed to reduce the incidence of nephrotoxicity in connection with the administration of urographic contrast media . We present the results of a r and omized study to explore the effect of a single hemodialysis treatment immediately after an angiographic examination . Material and Methods : The patients studied had moderately reduced renal function . Seventeen of the 32 patients had diabetic nephropathy and 15 had other renal diseases . They were r and omly selected to undergo either hemodialysis or st and ard treatment following the angiographic examination . The glomerular filtration rate ( GFR ) was determined the day before and 1 week after administration of the contrast medium . All patients were hydrated and received oral calcium-channel blocking treatment before angiography . Results : Hemodialysis lowered the level of contrast medium in plasma by approximately 80 % . In spite of this no significant difference in renal iohexol clearance was noted between groups treated and not treated with hemodialysis . Conclusions : The risk of a marked and sustained reduction in renal function after administration of an iodine contrast medium is low with modern angiographic techniques . Hemodialysis reduces levels of contrast media in plasma but does not reduce the incidence of contrast-medium-induced nephrotoxicity in the GFR range from 10 to 25 ml/min AIM The aim of the study was to investigate the role of hemofiltration in preventing contrast nephropathy in patients with renal failure . METHODS We r and omized 114 renal failure patients undergoing percutaneous coronary interventions ( PCI ) to either peri-procedural hemofiltration or saline hydration .  RESULTS Contrast nephropathy occurred in 5 % of hemofiltration-treated patients and in 50 % in controls ( P<0.01 ) . In-hospital event rate as well as in-hospital and 1-year mortality rates were lower in patients treated with hemofiltration . CONCLUSION In patients with renal failure undergoing PCI , peri-procedural hemofiltration is effective for the prevention of contrast nephropathy , and is associated with improved in-hospital and long-term outcome INTRODUCTION Worsening renal function during hospitalization for heart failure , defined as elevation in creatinine during admission , predicts adverse outcomes . Prior studies define worsening renal function using various creatinine elevations , but the relative value of definitions is unknown . METHODS AND RESULTS In a prospect i ve cohort of 412 patients hospitalized for heart failure , we compared a spectrum of worsening renal function definitions ( absolute creatinine elevations > /=0.1 to > /=0.5 mg/dL and 25 % relative elevation from baseline ) and associations with 6-month mortality , readmission , and functional decline .  Creatinine elevation > /=0.1 mg/dL occurred in 75 % of patients , and elevation > /=0.5 mg/dL occurred in 24 % of patients . Risk of death rose with higher creatinine elevations ( adjusted hazard ratio [ HR ] = 0.89 , 1.19 , 1.67 , 1.91 , and 2.90 for elevations > /=0.1 to > /=0.5 mg/dL ) . Maximum sensitivity of any definition for predicting mortality was 75 % and maximum specificity was 79 % . High creatinine elevation was a more important predictor of death than was a single measure of baseline creatinine . CONCLUSIONS Larger creatinine elevations predict highest risk of death , yet even minor changes in renal function are associated with adverse outcomes . The choice of a " best definition " for worsening renal function has implication s for the number of patients identified with this risk factor and the magnitude of risk for mortality BACKGROUND AND OBJECTIVE Radiographic contrast media ( CM ) administration causes a decline in renal function , especially in patients with pre-existing renal impairment . The value of CM removement by dialysis to prevent radiocontrast-induced nephropathy ( RCIN ) has not been established yet . The present study was design ed to investigate the influence of haemodialysis on renal function in patients with preexisting renal failure receiving CM for various purpose s. PATIENTS AND METHODS 15 patients with reduced renal function ( mean serum creatinine concentration 2.7 + /- 0.2 mg/dl ) were r and omly assigned to receive either haemodialysis for 2 - 3 hours , started as early as possible after administration of CM ( 106 + /- 25 minutes ) , or conservative treatment .  Serum creatinine and iodine concentrations were measured over 5 days . RESULTS The percentile creatinine increase on days 2 and 3 after CM application was higher in the dialysed group . The rate of RCIN ( defined as a serum creatinine increase of greater than or equal to 0.5 mg/dl within 48 h after administration of CM ) was significantly higher in the dialysed group ( 43 % in the haemodialysis group and 13 % in the group on conservative treatment , respectively ) . Iodine concentration declined earlier in the dialysed group . CONCLUSION Our data indicate that haemodialysis performed within two hours after CM application did not prevent the occurrence or the outcome of RCIN in patients with renal failure . In some patients haemodialysis even seems to have worse effects 
    Output:
    
Limiting analysis to only r and omized trials did not eliminate heterogeneity , but limiting analysis to only hemodialysis trials did .
Periprocedural hemodialysis did not decrease the incidence of RCIN .
CONCLUSION This critical analysis of the published literature suggests that periprocedural extracorporeal blood purification does not decrease the incidence of RCIN compared with st and ard medical therapy