***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: Background Although aspirin therapy started before operation improves vein graft patency after coronary artery bypass grafting , it also causes bleeding . The objective of this prospect i ve , central ly directed , r and omized , double-blind , placebo-controlled trial was to compare the effects of aspirin therapy started before operation with aspirin started 6 hours after operation on early ( 7–10-day ) graft patency . Methods and Results Patients were r and omized to receive either aspirin 325 mg or placebo the night before surgery ; after operation , all patients received aspirin 325 mg daily , with the first dose administered through the nasogastric tube 6 hours after operation . Angiography was performed in 72 % of the analyzed patients an average of 8 days after operation , and the primary end point was saphenous vein graft patency in 351 patients . Internal mammary artery graft patency was also assessed in 246 patients because many individuals received both internal mammary artery and vein grafts . In the patients given preoperative aspirin , the vein graft occlusion rate was 7.4 ± 1.3 % compared with 7.8 ± 1.5 % in those who received preoperative placebo ( p = 0.871 ) . In the subgroup of patients receiving Y grafts , 0.0 % of the grafts were occluded in the preoperative aspirin group compared with 7.0 ± 3.6 % in the preoperative placebo group ( p = 0.066 ) . The internal mammary artery occlusion rate was 0.0 % ( 0 of 131 ) in the aspirin group compared with 2.4 ± 1.4 % ( three of 125 ) in the placebo group ( p = 0.081 ) . Patients in the aspirin group received more transfusions than those in the placebo group ( median , 900 versus 725 ml , p=0.006 ) . The reoperation rate for bleeding in the aspirin group was 6.3 % compared with 2.4 % in the placebo group ( p = 0.036 ) . Median chest tube drainage within the first 6 hours after operation was 500 ml in the aspirin group compared with 448 ml in the placebo group ( p = 0.011 ) . Conclisions . Thus , preoperative aspirin is associated with increased bleeding complications and offers no additional benefit in early vein graft patency compared with starting aspirin therapy 6 hours after operation . There was a trend , although not significant , toward improved early patency for Y grafts and internal mammary artery grafts with preoperative aspirin OBJECTIVES Anaemia is a frequent complication after cardiopulmonary bypass surgery .  Iron therapy has been variably employed by medical centres over the years . In our study we test the clinical effectiveness of intravenous and oral iron supplementation in correcting anaemia , and its impact on blood transfusion requirements , in patients undergoing cardiopulmonary bypass surgery . METHODS A double-blind , r and omized , placebo-controlled clinical trial with three parallel groups of patients . Group I ( n = 54 ) : intravenous iron(III)-hydroxide sucrose complex , three doses of 100 mg/24 h during pre- and postoperative hospitalization and 1 pill/24 h of oral placebo in the same period and during 1 month after discharge . Group II ( n = 53 ) : oral ferrous fumarate iron 1 pill/24 h pre- and postoperatively and during 1 month after discharge , and intravenous placebo while hospitalized . Group III ( n = 52 ) : oral and intravenous placebo pre- and postoperatively , following the same protocol . Data were collected preoperatively , at theatre , at intensive care unit admission , before hospital discharge and 1 month later . RESULTS ( 1 ) Baseline clinical and demographic characteristics and surgical procedures were similar in the three groups ; ( 2 ) no inter-group differences were found in haemoglobin and haematocrit during the postoperative period ; ( 3 ) the intravenous iron group showed higher serum ferritin levels at hospital discharge ( 1321 ± 495 ng/ml ; P < 0.001 ) and 1 month later ( 610 ± 387 ; P < 0.001 ) compared with the other groups and ( 4 ) we did not observe statistical differences in blood transfusion requirements between the three groups . CONCLUSIONS The use of intravenous or oral iron supplementation proved ineffective in correcting anaemia after cardiopulmonary bypass and did not reduce blood transfusion requirements . [ Current Controlled Trials number : NCT01078818 ( oral and intravenous iron in patients postoperative cardiovascular surgery under EC ) ] BACKGROUND We tried to evaluate the clinical outcomes ( mortality , postoperative bleeding and perioperative myocardial infa rct ion ) of patients who underwent first elective coronary artery bypass grafting and received aspirin during the preoperative period . METHODS The study was a prospect i ve , r and omized and single-blinded clinical trial . Two hundred patients were included and divided into two groups . One group received aspirin 80 - 160 mg , while in the other aspirin was stopped at least seven days before surgery . The primary end-points of the study were in-hospital mortality and hemorrhage-related complications ( postoperative blood loss in the intensive care unit , re-exploration for bleeding and red blood cell and non-red blood cell requirements ) . The secondary end-point was perioperative myocardial infa rct ion . RESULTS There were no differences in patient characteristics between the aspirin users and non-aspirin users . We found a significant difference between postoperative blood loss ( 608 + /- + /- 359.7 ml vs. 483 + /- 251.5 ml ; p = 0.005 ) and red blood cell product requirements ( 1.32 + /- + /- 0.97 unit packed cell vs. 0.94 + /- 1.02 unit packed cell ; p = 0.008 ) . There was no significant difference between the two groups regarding platelet requirement and the rate of in-hospital mortality and re-exploration for bleeding . Similarly , we found no significant difference in the incidence of definite and probable perioperative myocardial infa rct ion ( p = 0.24 and p = 0.56 respectively ) or in-hospital mortality between the two groups . CONCLUSION Preoperative aspirin administration increased postoperative bleeding and red blood cell requirements with no effect on mortality , re-exploration rate and perioperative myocardial infa rct ion . We recommend withdrawal of aspirin seven days prior to surgery . ( Cardiol J 2007 ; 14 : 453 - 457 ) Patients undergoing aortocoronary bypass using autogenous saphenous veins were r and omly divided into three comparable groups . Group 1 ( n = 10 ) acted as a control , Group 2 ( n = 14 ) received 80 mg of aspirin at midnight before the operation , and Group 3 ( n = 12 ) received 80 mg of aspirin and 75 mg of dipyridamole at midnight and an additional 75-mg dose of dipyridamole at 6 AM . The purpose was to determine which regimen would maximally inhibit platelet function without depressing vascular prostacyclin synthesis . Serum thromboxane A2 , saphenous vein wall and aortic wall prostacyclin , platelet aggregation , and bleeding time were measured in all patients . None was restarted on a regimen of aspirin or dipyridamole postoperatively . Aspirin alone and in combination with dipyridamole significantly inhibited thromboxane A2 and platelet aggregation in all treated patients but spared venous prostacyclin synthesis . Aortic prostacyclin synthesis was partially inhibited in both treated groups . Chest tube drainage was comparable in all three groups . These results indicate that the combination of aspirin and dipyridamole offers no measurable advantage over aspirin alone in the perioperative period Background and Objectives This trial explores whether intravenous iron isomaltoside 1000 ( Monofer ® ) results in a better regeneration of haemoglobin levels and prevents anaemia compared to placebo in preoperative non-anaemic patients undergoing cardiac surgery . Study Design and Methods The trial is a prospect i ve , double-blind , comparative , placebo-controlled trial of 60 non-anaemic patients undergoing cardiac surgery . The patients were r and omized 1:1 to either 1000 mg intravenous iron isomaltoside 1000 administered perioperatively by infusion or placebo . Results Mean preoperative haemoglobin in the active treatment group was 14·3 g/dl vs. 14·0 g/dl in the placebo group . At discharge 5 days after surgery , haemoglobin levels were reduced to 10·7 and 10·5 g/dl , respectively . One month after surgery , haemoglobin concentration had increased to an average of 12·6 g/dl vs. 11·8 g/dl ( p = 0·012 ) and significantly more patients were non-anaemic in the intravenous iron isomaltoside 1000-treated group compared to the placebo group ( 38·5 % vs. 8·0 % ; p = 0·019 ) . There were no differences in side-effects between the groups . Conclusion A single perioperative 1000 mg dose of intravenous iron isomaltoside 1000 significantly increased the haemoglobin level and prevented anaemia 4 weeks after surgery , with a short-term safety profile similar to placebo . Future trials on potential clinical benefits of preoperative treatment with intravenous iron in non-anaemic patients are needed BACKGROUND Symptomatic or asymptomatic  deep vein thrombosis  (  DVT ) is a common complication following coronary artery bypass graft ( CABG ) , in which less than 1 % of these patients suffer from clinical ly evident pulmonary embolism ( PE ) . DVT and PE can increase other morbidities of coronary revascularization from short to long period , but no clear consensus still exists regarding proper thromboprophylaxis strategy in the literature s. This study was design ed to compare the anti-platelet prophylaxis of aspirin plus heparin with heparin alone on asymptomatic perioperative DVT in patients that are c and i date s for elective off-pump CABG . METHODS One hundred and twenty patients , who are c and i date s for elective off-pump CABG , were r and omly assigned to two groups : the aspirin plus heparin group ( Group 1 , n = 60 ) that received 80 mg daily aspirin orally and 5000 U unfractionated heparin per 8 h subcutaneously from admission to discharge time , and the heparin group ( group 2 , n = 60 ) that received same dose of heparin alone . All patients underwent right and left leg venous ultrasound examination during hospitalization , after which post-operative off-pump CABG complications such as deep vein thrombosis , bleeding and pulmonary embolism were evaluated in this study cases . RESULTS The mean age of the patients was 62.10 ± 10.71 years with a male to female ratio of 2.24 . Asymptomatic DVT occurred in 12 ( 10 % ) patients who underwent elective off-pump CABG . DVT was found more in Group 2 ( 16.6 % ) as compared to Group 1 ( 3.3 % ) with statistical significant difference ( p = 0.015 ) . Bleeding was detected in 5 ( 4.1 % ) cases in the patients sample d in this study ( p = 0.34 ) , 4 cases of which are from Group 1 and 1 case from Group 2 . However , PE was shown in none of this study cases . CONCLUSIONS The incidence of DVT decreased more with aspirin plus heparin as compared to heparin alone in patients who underwent elective off-pump CABG . As regards the results obtained in this study , more studies need to be conducted to establish this strategy for prophylaxis of DVT in CABG Aspirin has an established benefit in reducing the incidence of coronary events and vein graft occlusion . We have now assessed the risk of pre-operative aspirin in a prospect i ve , r and omised , double-blind clinical trial in 100 patients scheduled for elective coronary artery surgery . Any prescribed aspirin and non-steroidal anti-inflammatory drugs were discontinued 2 weeks pre-operatively and these were replaced by a r and omly assigned tablet of either aspirin 300 mg daily or placebo taken until the day of surgery . Patient compliance was confirmed by serum and urinary salicylate analysis . The two groups were similar in demographic characteristics , bypass time , number of grafts placed and number of internal mammary arteries used . All patients  survived to be discharged home ( see Table ) . Aspirin decreases platelet aggregation to arachidonic acid and to collagen both pre- and post-operatively . The benefit of pre-operative aspirin has to be balanced against the risk of increasing post-operative blood loss , re-exploration for excessive bleeding and transfusion requirements OBJECTIVE To determine whether slow-release enteric coated aspirin ( 100 mg daily ) , commenced before 
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This meta- analysis found no statistically significant difference regarding the risk of operative mortality and myocardial infa rct ion between the ' continuing ASA ' and ' stopping ASA ' strategies .
On the other h and , the mean volume of blood loss and packed red blood cell transfusion was higher in the ' continuing ASA ' group , but this finding did not translate into higher risk of reoperation for bleeding