Association of Warfarin Therapy Duration After Bioprosthetic Aortic Valve Replacement With Risk of Mortality, Thromboembolic Complications, and Bleeding
What are associations between warfarin treatment and the risk of thromboembolic complications, bleeding, and cardiovascular death after bioprosthetic aortic valve replacement (AVR)?
This was a retrospective study of patients in the Danish National Patient Registry who had bioprosthetic AVR between 1997 and 2009. The main outcome measures were time-dependent incidence rate ratios of stroke, thromboembolic events, and bleeding by discontinuing warfarin versus continued anticoagulation postoperatively.
Estimated rates of events per 100 person-years in patients not treated with warfarin compared with those treated with warfarin with comparative absolute risks were 31.74 (95% confidence interval [CI], 24.69-40.79) versus 3.83 (95% CI, 2.35-6.25) for cardiovascular deaths within 30-89 days after surgery; and 6.50 (95% CI, 4.67-9.06) versus 2.08 (95% CI, 0.99-4.36) for cardiovascular deaths within 90-179 days after surgery. For every 23 (95% CI, 14-54) patients not being treated with warfarin, one patient died from cardiovascular cause. For every 74 (95% CI, 27-95) patients being treated with warfarin, one patient experienced bleeding requiring hospitalization.
Warfarin in the initial 3-6 months after bioprosthetic AVR is associated with a reduced risk of cardiovascular death.
Current guidelines, which suggest 3 months of postoperative warfarin following bioprosthetic AVR, are based on limited data. The current study, although limited by a retrospective study design and the lack of some data (e.g., time in therapeutic range) in an administrative database, offers compelling evidence for warfarin in the initial 3 months after surgery, and even up to 6 months postoperatively. These data implicate a need to revisit the guidelines and, at a minimum, suggest broader adherence to short-term warfarin following a bioprosthetic AVR.
Keywords: Outcome Assessment (Health Care), Incidence, Heart Valve Prosthesis, Blood Coagulation, Bioprosthesis, Cardiology, Warfarin, Hemorrhage, Postoperative Period
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