Comparison of warfarin and aspirin for symptomatic intra- cranial arterial stenosis. N Engl J Med. 2005;352(13):1305-1316. 80. Connolly S, Pogue J, Hart R, et al; ACTIVE Writing Group of the ACTIVE Investigators. Clopidogrel plus aspirin ver- sus oral anticoagulation for atrial brillation in the Atrial brillation Clopidogrel Trial with Irbesartan for preven- tion of Vascular Events (ACTIVE W): a randomised con- trolled trial. Lancet. 2006;367(9526):1903-1912. 81. Connolly SJ, Pogue J, Hart RG, et al; ACTIVE Investigators. Effect of clopidogrel added to aspirin in patients with atrial brillation. N Engl J Med. 2009;360(20):2066-2078. 82. Olsson SB; Executive Steering Committee of the SPORTIF III Investigators. Stroke prevention with the oral direct thrombin inhibitor ximelagatran compared with warfarin in patients with non-valvular atrial brillation (SPORTIF III): randomised controlled trial. Lancet. 2003; 362(9397):1691-1698. 83. Albers GW, Diener HC, Frison L, et al; SPORTIF Execu- tive Steering Committee for the SPORTIF V Investigators. Ximelagatran vs warfarin for stroke prevention in patients with nonvalvular atrial brillation: a randomized trial. JAMA. 2005;293(6):690-698. 84. Connolly SJ, Ezekowitz MD, Yusuf S, et al; RE-LY Steering Committee and Investigators. Dabigatran versus warfarin in patients with atrial brillation. N Engl J Med. 2009;361(12):1139-1151. 85. Patel MR, Mahaffey KW, Garg J, et al; ROCKET AF Investigators. Rivaroxaban versus warfarin in nonvalvular atrial brillation. N Engl J Med. 2011;365(10):883-891. 86. Connolly SJ, Eikelboom J, Joyner C, et al; AVERROES Steering Committee and Investigators. Apixaban in patients with atrial brillation. N Engl J Med. 2011;364(9):806-817. 87. Granger CB, Alexander JH, McMurray JJ, et al; ARISTOTLE Committees and Investigators. Apixaban versus warfarin in patients with atrial brillation. N Engl J Med. 2011;365(11): 981-992. 88. Roskell NS, Lip GY, Noack H, Clemens A, Plumb JM. Treatments for stroke prevention in atrial brillation: a network meta-analysis and indirect comparisons versus dab- igatran etexilate. Thromb Haemost. 2010;104(6):1106-1115. 89. 