You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
Preservation of cadaveric renal allografts-comparison of flushing and pumping techniques.
Abstract 1:
A prospect i ve clinical trial comparing flushing and ice storage using a new hypertonic citrate solution , with machine preservation by continuous perfusion showed early graft function was similar with each method , and preservation times were comparable . Good early function occurred in half the grafts with preservation times up to 24 hours . Graft survival at three and 12 months was similar with each method of preservation . Graft survival at 12 months was worsened by poor early graft function , whereas patient survival at 12 months was unaffected by early function or by the method of preservation


Title 2:
A CONTROLLED CLINICAL TRIAL OF MACHINE PERFUSION OF CADAVERIC DONOR RENAL ALLOGRAFTS
Abstract 2:
Outcome in eighty-eight recipients of cadaveric donor renal allografts preserved before implantation by machine perfusion with a solution of human albumin was compared to that for eighty-three recipients of similar kidneys implanted after simple cold storage .  Average total ischaemic intervals for machine-perfused and cold-stored kidneys were 18 and 4 1/4 hours , respectively . Machine-perfused kidneys were implanted regardless of perfusion characteristics . Initial function and 1-month and 1-year graft survivals for the machine-perfused group ( 58 % , 85 % , 68 % , respectively ) were either similar or improved compared to those of cold-stored kidneys ( 58 % , 81 % , 52 % , respectively ) . Improved 1-year survival for machine-perfused grafts was dependent upon reduced rejection . Careful donor selection and management ensured good machine perfusion of kidneys on 90 % of occasions . In the other 10 % , despite poor perfusion characteristics , outcome for kidneys was similar to those with good perfusion characteristics . Antilymphocyte globulin treatment reduced rejection whether allografts were machine perfused or not . In the absence of antilymphocyte globulin treatment , machine-perfused kidneys did much better than cold-stored kidneys . Machine perfusion had important advantages and improved the results in kidney-graft recipients


Title 3:
Cold Machine Perfusion Versus Static Cold Storage of Kidneys Donated After Cardiac Death: A UK Multicenter Randomized Controlled Trial
Abstract 3:
One third of deceased donor kidneys for transplantation in the UK are donated following cardiac death ( DCD ) . Such kidneys have a high rate of delayed graft function ( DGF ) following transplantation . We conducted a multicenter , r and omized controlled trial to determine whether kidney preservation using cold , pulsatile machine perfusion ( MP ) was superior to simple cold storage ( CS ) for DCD kidneys . One kidney from each DCD donor was r and omly allocated to CS , the other to MP . A sequential trial design was used with the primary endpoint being DGF , defined as the necessity for dialysis within the first 7 days following transplant . The trial was stopped when data were available for 45 pairs of kidneys . There was no difference in the incidence of DGF between kidneys assigned to MP or CS ( 58 % vs. 56 % , respectively ) , in the context of an asystolic period of 15 min and median cold ischemic times of 13.9 h for MP and 14.3 h for CS kidneys . Renal function at 3 and 12 months was similar between groups , as was graft and patient survival . For kidneys from controlled DCD donors ( with mean cold ischemic times around 14 h ) , MP offers no advantage over CS , which is cheaper and more straightforward


Title 4:
Machine Perfusion Versus Cold Storage for the Preservation of Kidneys Donated After Cardiac Death: A Multicenter, Randomized, Controlled Trial
Abstract 4:
Objective : Hypothermic machine perfusion may improve outcome after transplantation of kidneys donated after cardiac death ( DCD ) , but no sufficiently powered prospect i ve studies have been reported . Because organ shortage has led to an increased use of DCD kidneys , we aim ed to compare hypothermic machine perfusion with the current st and ard of static cold storage preservation . Methods : Eighty-two kidney pairs from consecutive , controlled DCD donors 16 years or older were included in this r and omized controlled trial in Eurotransplant . One kidney was r and omly assigned to machine perfusion and the contralateral kidney to static cold storage according to computer-generated lists created by the permuted block method . Kidneys were allocated according to st and ard rules , with concealment of the preservation method . Primary endpoint was delayed graft function ( DGF ) , defined as dialysis requirement in the first week after transplantation . All 164 recipients were followed until 1 year after transplantation . Results : Machine perfusion reduced the incidence of DGF from 69.5 % to 53.7 % ( adjusted odds ratio : 0.43 ; 95 % confidence interval 0.20–0.89 ; P = 0.025 ) . DGF was 4 days shorter in recipients of machine-perfused kidneys ( P = 0.082 ) . Machine-perfused kidneys had a higher creatinine clearance up to 1 month after transplantation ( P = 0.027 ) . One-year graft and patient survival was similar in both groups ( 93.9 % vs 95.1 % ) . Conclusions : Hypothermic machine perfusion was associated with a reduced risk of DGF and better early graft function up to 1 month after transplantation . Routine preservation of DCD kidneys by hypothermic machine perfusion is therefore advisable
Pulsatile machine perfusion of donation after cardiac death kidneys appears to decrease the delayed graft function rate .
We noted no benefit in 1-year graft survival .