Anticoagulation and Antiplatelet Strategies After On-X Mechanical Aortic Valve Replacement.

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Anticoagulation and Antiplatelet Strategies After On-X Mechanical Aortic Valve Replacement.

J Am Coll Cardiol. 2018 Jun 19;71(24):2717-2726

Authors: Puskas JD, Gerdisch M, Nichols D, Fermin L, Rhenman B, Kapoor D, Copeland J, Quinn R, Hughes GC, Azar H, McGrath M, Wait M, Kong B, Martin T, Douville EC, Meyer S, Ye J, Jamieson WRE, Landvater L, Hagberg R, Trotter T, Armitage J, Askew J, Accola K, Levy P, Duncan D, Yanagawa B, Ely J, Graeve A, PROACT Investigators

Abstract
BACKGROUND: The burden oral anticoagulation is a limitation of mechanical valve prostheses.
OBJECTIVES: The aim of this study was to test whether patients could be safely managed with dual-antiplatelet therapy (DAPT) (aspirin 325 mg and clopidogrel 75 mg) or lower warfarin after On-X mechanical aortic valve replacement (mAVR).
METHODS: PROACT (Prospective Randomized On-X Anticoagulation Trial) (n = 576) is a multicenter (41 sites) noninferiority trial. From June 2006 through February 2014, 201 patients ≥18 years of age without thromboembolic risk factors undergoing mAVR were randomized to receive DAPT (n = 99) or standard warfarin plus aspirin (n = 102) 3 months after mAVR (low-risk arm). From June 2006 through October 2009, 375 patients with 1 or more thromboembolic risk factors were also randomized to lower intensity warfarin plus aspirin (international normalized ratio 1.5 to 2.0; n = 185) or standard warfarin plus aspirin (international normalized ratio 2.0 to 3.0; n = 190) 3 months after mAVR (high-risk arm).
RESULTS: The low-risk arm was terminated for excess cerebral thromboembolic events (3.12% per patient-year vs. 0.29% per patient-year, p = 0.02) in the DAPT group at up to 8.8-year follow-up (631.6 patient-years), with no differences in bleeding or all-cause mortality. High-risk arm patients experienced significantly lower major (1.59% per patient-year vs. 3.94% per patient-year, p = 0.002) and minor (1.27% per patient-year vs. 3.49% per patient-year, p = 0.002) bleeding up to 8.7-year follow-up (2,035.2 patient-years), with no differences in thromboembolism (0.42% per patient-year vs. 0.09% per patient-year, p = 0.20) and all-cause mortality.
CONCLUSIONS: DAPT was associated with higher rates of thromboembolism and valve thrombosis compared with control in the low-risk arm. International normalized ratios were safely maintained at 1.5 to 2.0 in high-risk patients, without differences in mortality or thromboembolic complications. (Randomized On-X Anticoagulation Trial [PROACT]; NCT00291525).

PMID: 29903344 [PubMed - in process]

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