***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 : The benefit of heparin anticoagulation in patients undergoing intra-aortic balloon counterpulsation ( IABP ) is unproven . Methods : We determined the net clinical benefit ( or harm ) of heparin therapy during intra-aortic balloon counterpulsation ( IABP ) in the coronary care unit ( CCU ) by conducting a prospect i ve “ before- and -after ” analysis of consecutive patients . We compared a universal heparin ( UH ) strategy ( all patients given heparin ) to a selective heparin ( SH ) strategy ( heparin only for a clinical indication ) . Results : There were 102 patients in the UH group and 150 patients in the SH group . Among the SH group , 70 patients ( 47 % ) received no heparin .  Major IABP-related complications were uncommon in both groups ( 2.9 % versus 4.6 % , P=0.7 ) . Major limb ischemia occurred in one patient in the UH group ( overall incidence : 0.4 % ) . Major non-access-site bleeding was more common in the UH group ( 10.8 % versus 3.3 % , P=0.02 ) . Inclusion in the UH group was independently associated with the endpoints of : major limb ischemia or any major bleeding ( odds ratio ( OR ) 3.32 , P=0.03 ) , any major bleeding ( OR 3.35 , P=0.03 ) , and major limb ischemia , any major bleeding , or death ( OR 2.17 , P=0.03 ) . Conclusions : Among CCU patients undergoing IABP , a selective heparin strategy appears to be superior to a strategy of universal heparin use To assess the usefulness of intraaortic balloon pumping ( IABP ) in acute myocardial infa rct ion ( AMI ) , 114 patients with anterior AMI undergoing emergency percutaneous transluminal coronary angioplasty ( PTCA ) for total occlusion of the left anterior descending artery were studied . After successful PTCA 66 patients were treated with conventional therapy ( group I ) , and 48 patients were treated with IABP for 25 + /- 8 hours ( group II ) . The reocclusion rate was significantly lower in group II ( 2.4 % vs 17.7 % p less than 0.05 ) . An increase in ejection fraction in group II compared with group I was marginally significant ( 4.5 + /- 12.2 % vs 9.2 + /- 13.0 % , p = 0.08 ) . Vascular complications occurred in two patients , but there were no deaths from IABP . These results suggest that after successful PTCA for acute myocardial infa rct ion , IABP prevents reocclusion and may add strength to reperfusion in the improvement of left ventricular function Background —Recovery of myocardial function after revascularization of acutely occluded coronary arteries may require several days . During this critical time , patients in cardiogenic shock may have low output . A newly developed percutaneous left ventricular assist device ( VAD ) may offer effective treatment for these patients by providing active circulatory support . Methods and Results —Between May 2000 and May 2001 , VADs were implanted in 18 consecutive patients who had cardiogenic shock after myocardial infa rct ion . The device was connected to the patient ’s circulation by insertion of a 21F venous cannula into the left atrium by transseptal puncture ; blood was returned to the iliac artery through an arterial cannula . Mean duration of cardiac assistance was 4±3 days . Mean flow of the VAD was 3.2±0.6 L/min . Before support , cardiac index was 1.7±0.3 L/min per m2 and improved to 2.4±0.6 L/min per m2 ( P < 0.001 ) . Mean blood pressure increased from 63±8 mm Hg to 80±9 mm Hg ( P < 0.001 ) . Pulmonary capillary wedge pressure , central venous pressure , and pulmonary artery pressure were reduced from 21±4 , 13±4 , and 31±8 mm Hg to 14±4 , 9±3 , and 23±6 mm Hg ( all P < 0.001 ) , respectively . Overall 30-day mortality rate was 44 % . Conclusions —A newly developed VAD can be rapidly deployed in the catheterization laboratory setting . This device provides up to 4.0 L/min of assisted cardiac output , which may aid to revert cardiogenic shock . The left ventricle is unloaded by diverting blood from the left atrium to the systemic circulation , making recovery more likely after an ischemic event . The influence of this device on long-term prognosis warrants further investigation Intra-aortic balloon counterpulsation ( IABP ) related complications in a heterogeneous group of patients who received an IABP before or after thrombolytic therapy and mechanical revascularization or in the management of refractory unstable angina and myocardial infa rct ion related mechanical complications were evaluated prospect ively . Ninety-one patients were enrolled to the study . Mean IABP duration was 4.3+/-2.4 days . While the IABP was in place , three patients ( 3.3 % ) had femoral artery emboli , four patients ( 4.4 % ) had lower extremity ischemia that resolved after the removal of the balloon , eight patients ( 8.8 % ) had groin hematoma requiring blood transfusion ( < or = 2 units ) and four patients ( 4.4 % ) had intra-aortic balloon rupture . The relation of several risk factors to groin hematoma requiring < or = 2 units blood transfusion , emboli , lower extremity ischemia and to total complications was evaluated . A chi-squared analysis showed that  nadroparine use was more often complicated with emboli ( P = 0.00005 ) and ischemic events ( emboli and /or lower extremity ischemia ) ( three patients ; 30 % of nadroparine group vs. four patients ; 4.9 % of heparin group , P = 0.005 ) and hypercholesterolemia ( > 200 mg/dl ) was more often complicated with lower extremity ischemia ( P = 0.017 ) . Forward conditional logistic regression analysis did not show any relation between the risk factors identified and emboli , lower extremity ischemia , ischemic events and groin hematoma ( P>0.05 ) , but an inverse relation was found between IABP duration and total complications ( P = 0.0198 ) . In conclusion , IABP related complications were found to remain unchanged but were not life-threatening and were inversely related to IABP duration and this suggests shorter periods of IABP use whenever possible and one must be cautious to use low molecular weight heparin in patients with an IABP in place 
    Output:
    
While differences in survival were comparable in patients treated with IABP , with and without LVAD , haemodynamics and incidences of device related complications show heterogeneous results .
Available evidence suggests that IABP may have a beneficial effect on the haemodynamics , however there is no convincing r and omised data to support the use of IABP in infa rct related cardiogenic shock