***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 Common clinical practice recommends dual antiplatelet therapy ( DAPT ) for  transcatheter aortic valve implantation ( TAVI ) . The aim of the study was to evaluate , in a double blind r and omized study , the safety of TAVI , with adjunctive pharmacotherapy consisting of single antiplatelet therapy . METHODS AND RESULTS From April 2010 to April 2011 , 120 consecutive patients , undergoing TAVI , have been enrolled in the study . Patients were r and omly assigned to DAPT group ( aspirin and clopidogrel 75 mg/qd or ticlopidine 500 mg/bid ) or ASA group ( aspirin only ) . TAVI device was the Sapien XT-Novaflex Delivery System ( Edwards Lifesciences , Inc. ) . All patients were followed up to 6 months . Device success was achieved in 100 % of patients . No difference in the VARC combined 30 day safety endpoint , all cause and cardiovascular mortality was observed . At 30 days vascular complications were reduced in the ASA group ( p<0.05 ) . No differences in the clinical status were detected between the groups up to 6 months . CONCLUSIONS This study suggests that TAVI procedures can be performed without DAPT without increasing the morbidity and mortality . These findings , if confirmed in a larger multicenter r and omized trial , will no longer support the use of DAPT for TAVI OBJECTIVES The aim of this study was to compare aspirin plus clopidogrel with aspirin alone as antithrombotic treatment following transcatheter aortic valve replacement ( TAVR ) for the prevention of ischemic events , bleeding events , and death . BACKGROUND Few data exist on the optimal antithrombotic therapy following TAVR . METHODS This was a r and omized controlled trial comparing aspirin ( 80 to 100 mg/day ) plus clopidogrel ( 75 mg/day ) ( dual antiplatelet therapy [ DAPT ] ) versus aspirin alone ( single-antiplatelet therapy [ SAPT ] ) in patients undergoing TAVR with a balloon-exp and able valve . The primary endpoint was the occurrence of death , myocardial infa rct ion ( MI ) , stroke or transient ischemic attack , or major or life-threatening bleeding ( according to Valve Academic Research Consortium 2 definitions ) within the 3 months following the procedure . The trial was prematurely stopped after the inclusion of 74 % of the planned study population . RESULTS A total of 222 patients were included , 111 allocated to DAPT and 111 to SAPT . The composite of death , MI , stroke or transient ischemic attack , or major or life-threatening bleeding tended to occur more frequently in the DAPT group ( 15.3 % vs. 7.2 % , p = 0.065 ) . There were no differences between groups in the occurrence of death ( DAPT , 6.3 % ; SAPT , 3.6 % ; p = 0.37 ) , MI ( DAPT , 3.6 % ; SAT , 0.9 % ; p = 0.18 ) , or stroke or transient ischemic attack ( DAPT , 2.7 % ; SAPT , 0.9 % ; p = 0.31 ) at 3 months . DAPT was associated with a higher rate of major or life-threatening bleeding events ( 10.8 % vs. 3.6 % in the SAPT group , p = 0.038 ) . There were no differences between groups in valve hemodynamic status post-TAVR . CONCLUSIONS This small trial showed that SAPT ( vs. DAPT ) tended to reduce the occurrence of major adverse events following TAVR . SAPT reduced the risk for major or life-threatening events while not increasing the risk for MI or stroke . Larger studies are needed to confirm these results . ( Aspirin Versus Aspirin + Clopidogrel Following Transcatheter Aortic Valve Implantation : The ARTE Trial [ ARTE ] , NCT01559298 ; Aspirin Versus Aspirin+Clopidogrel as Antithrombotic Treatment Following TAVI [ ARTE ] , NCT02640794 ) BACKGROUND A new third generation porcine bioprosthesis was developed in an attempt to improve on hemodynamic performance and durability of current prostheses . METHODS One thous and , two hundred , sixty patients underwent aortic valve replacement and 366 patients underwent mitral valve replacement between February 1994 and September 2000 . The cumulative follow-up was 3,696.3 patient-years for aortic valve replacement and 880.1 patient-years for mitral valve replacement . Follow-up was complete for 95.5 % of aortic valve replacement patients and 97.5 % of mitral valve replacement patients . RESULTS For aortic valve replacement , freedom from valve-related adverse events at 1 year was 96.5%+/-0.5 % for antithromboembolic-related hemorrhage and 100 % for structural valve deterioration . Freedom from valve-related adverse events at 5 years was 93.8%+/-2.6 % for antithromboembolic-related hemorrhage and 99.3%+/-0.9 % for structural valve deterioration . For mitral valve replacement , freedom from valve-related adverse events at 1 year was 96.0%+/-1.1 % for antithromboembolic-related hemorrhage and 100 % for structural valve deterioration . Freedom from valve-related adverse events at 4 years was 92.1%+/-3.7 % for antithromboembolic-related hemorrhage and 100 % for structural valve deterioration . CONCLUSIONS These results support the cl aim that the Mosaic bioprosthetic valve is efficacious and safe , but continued follow-up is m and atory to determine mid- and long-term performance BACKGROUND To identify the optimal use of anticoagulants after Carpentier-Edwards valve replacement , a retrospective study of all patients undergoing Carpentier-Edwards aortic ( N = 378 ) or mitral ( N = 370 ) valve replacement was done . METHODS AND RESULTS At the time of hospital discharge , 103 patients were managed with warfarin , 509 with aspirin alone , and 136 with no anticoagulation or antiplatelet therapy .  Over the first 90 days after aortic or mitral valve replacement , the linearized rate of hemorrhage was greater for warfarin than for aspirin or no therapy ( 16.7 + /- 7.6 % , 3.4 + /- 1.7 % , and 3.1 + /- 3.1 % per patient-year , respectively ; P = .03 ) . After aortic valve replacement , aspirin provided a low rate of thromboembolism ( 0.8 + /- 0.2 % per patient-year ) , not significantly different from warfarin or no treatment ( 2.9 + /- 1.6 % and 1.5 + /- 0.6 % per patient-year ) ( P = .07 ) . After mitral valve replacement , no single treatment was most advantageous because the rate of hemorrhage over the first 90 days for warfarin was equivalent to the 90-day rate of thromboembolism with aspirin or no therapy . CONCLUSIONS Anticoagulation after Carpentier-Edwards mitral valve replacement may be best guided by individual patient characteristics . Within the limits of a retrospective analysis , these data support the routine use of aspirin alone after Carpentier-Edwards aortic valve replacement , both in the first 90 days and long-term Background — Patients with prosthetic heart valves have a higher risk of developing valve thrombosis and arterial thromboembolism .  Antithrombotic therapy in the early postoperative period after biological aortic valve replacement ( BAVR ) is controversial . The American College of Cardiology/American Heart Association and European Society of Cardiology guidelines recommend the use of warfarin for the first 3 months after BAVR , although the American College Chest Physician guidelines suggest that the recommendations are very weak and that the risk/benefit is unclear . This prospect i ve study investigated the efficacy of postoperative warfarin compared with aspirin in patients after aortic valve replacement . Methods and Results — Patients undergoing BAVR between 2001 and 2002 received 2 antithrombotic therapies  : 141 patients received warfarin for the first 3 months , and 108 patients received only aspirin .  The major end points evaluated were the rate of cerebral ischemic events , bleeding , and survival . There were 3 and 5 postoperative cerebral ischemic events between 24 hours and 3 months for patients treated with aspirin and warfarin , respectively . After 3 months , the incidence of cerebral ischemic events did not differ between the 2 groups . The rate of major bleeding events , the stroke-free survival , and the overall survival rates were not statistically significant between the warfarin and aspirin groups . Conclusions —There seem to be no advantages in performing early anticoagulation therapy compared with a low-antiplatelet regimen with regard to early cerebral ischemic events , bleeding , and survival . Currently there is no evidence to support the fact that warfarin is more effective than aspirin BACKGROUND AND AIM OF THE STUDY Patients with bioprosthetic heart valves have a higher risk of developing peripheral arterial embolic phenomena than the normal population . Antithrombotic therapy during the early postoperative period after bioprosthetic aortic valve replacement ( BAVR ) is controversial . This prospect i ve pilot study sought to investigate the feasibility of a larger trial and the efficacy of postoperative warfarin compared to acetyl salicylic acid ( aspirin ; ASA ) in patients after AVR with the St. Jude Epic porcine bioprosthesis ( SJEP ) , and the feasibility of conducting a larger trial . METHODS Patients undergoing isolated BAVR were allocated at r and om to two groups , each of which received different antithrombotic therapies : ( i ) warfarin ( INR ; range 2 - 3 ) for the first three months , followed by ASA ( 100 mg/day ) ; or ( ii ) ASA alone ( 100 mg/day ) . RESULTS During 2003 and 2004 , a total of 75 patients underwent isolated BAVR with the SJEP . Six patients who developed postoperative de-novo atrial fibrillation that did not revert to sinus rhythm were excluded from the analysis , but included in the follow up . One postoperative cerebral ischemic event occurred in each group between 24 h and three months ( 2.8 % versus 2.9 % , p = NS ) . The rates of major bleeding , stroke-free survival and overall survival were similar in both groups . CONCLUSION The early results of this WoA Epic pilot trial did not support the suggestion that patients receiving the SJEP , and tissue valves in general , should be administered warfarin to prevent valve thrombosis and peripheral arterial embolic phenomena BACKGROUND The midterm clinical and hemodynamic performance of the Medtronic Mosaic porcine bioprosthesis was evaluated in a regulatory trial . METHODS In nine Canadian centers , 802 bioprostheses ( 560 aortic and 242 mitral ) were implanted between September 1994 and April 1999 in patients with a mean age of 70 years . RESULTS Survival for aortic valve replacement at 4 years was 84.4%+/-3.1 % . Freedom from valve-related or unexplained death was 95.6%+/-1.9 % ; structural valve deterioration , 100.0 % ; reoperation , 96.2%+/-1.7 % ; major thromboembolism , 96.1%+/-1.8 % ; and major antithrombotic-related hemorrhage , 96.4%+/-1.7 % . Echocardiographic derived mean systolic gradient was 13.4 mm Hg at 4 years with an indexed effective orifice area of 0.7 to 0.8 cm2/m2 . A significant decrease in left ventricular mass was shown over time in all valve sizes . Survival for mitral valve replacement at 4 years was 79.2%+/-6.8 % . Freedom from valve-related or unexplained death was 96.5%+/-3.4 % ; structural valve deterioration , 100 % ; reoperation , 97.0%+/-3.2 % ; major thromboembolism , 95.7%+/-3.8 % ; and major antithrombotic-related hemorrhage , 95.0%+/-4.2 % . Echocardiographically measured averaged mean diastolic gradient was 4.5 mm Hg . CONCLUSIONS The Medtronic Mosaic bioprosthesis is safe and effective in both the aortic and mitral positions . The valve has low gradients in both positions and excellent left ventricular mass regression in the patients with aortic valve replacement Background — No human physiological data exists on whether aspirin only is as effective as warfarin plus aspirin in preventing cerebral microembolization in the early postoperative period after bioprosthetic aortic valve replacement ( bAVR ) 
    Output:
    
We found moderate-strength evidence that mortality , thromboembolic events , and bleeding rates are similar between aspirin and warfarin after surgical bAVR .
Observational data suggest lower mortality and thromboembolic events with aspirin combined with warfarin compared with aspirin alone after surgical bAVR , but the effect size is small and the combination is associated with a substantial increase in bleeding risk .
We found insufficient evidence for all other treatment comparisons in surgical bAVR .
In TAVR patients , we found moderate-strength evidence that mortality , stroke , and major cardiac events are similar between dual antiplatelet therapy and aspirin alone , though a nonsignificantly lower rate of bleeding occurred with aspirin alone .
Treatment with warfarin or aspirin leads to similar outcomes after surgical bAVR .
Combining aspirin with warfarin may lead to a small decrease in thromboembolism and mortality , but is accompanied by increased bleeding .
For TAVR patients , aspirin is equivalent to dual antiplatelet therapy for reducing thromboembolism and mortality , with a possible decrease in bleeding