Determinants of low-quality warfarin anticoagulation in patients with mechanical prosthetic heart valves. The nationwide PLECTRUM study

Quality of warfarin therapy in patients with a mechanical prosthetic heart valve (MPHV) has been barely investigated. We analysed determinants of low time in the therapeutic range (TiTR <60%) in 2111 patients with MPHVs from the nationwide PLECTRUM study by the Italian Federation of Anticoagulation Clinics. Overall, 48 center dot 5% of patients had a TiTR of < 60%. At logistic regression analysis, arterial hypertension (odds ratio [OR] 1 center dot 502, P < 0 center dot 001), diabetes (OR 1 center dot 732, P < 0 center dot 001), heart failure (OR 1 center dot 484, P = 0 center dot 004), mitral site (vs. aortic) (OR 1 center dot 399, P = 0 center dot 006), international normalised ratio (INR) ranges of 2 center dot 5-3 center dot 5 (OR 2 center dot 575, P < 0 center dot 001) and 3 center dot 0-4 center dot 0 (OR 8 center dot 215, P < 0 center dot 001) associated with TiTR < 60%. TiTR is substantially suboptimal in MPHV patients, particularly in higher INR ranges.