Abstract 14264: Vitamin E Serum Level, a New Tool to Stratify Bleeding Risk in Patients Receiving Oral Anticoagulant Therapy
BACKGROUND: Hemorrhagic risk assessment is a crucial issue in patients receiving oral anticoagulant therapy (OAT). Vitamin E possesses anti-coagulant/antiplatelet properties.
AIMS: to see if a relationship between vitamin E serum levels and bleeding does exist.
METHODS: We prospectively analyzed vitamin E levels in 407 consecutive patients with non-valvular atrial fibrillation (NVAF) under OAT followed-up for a mean of 22 months (745 patients/year). Exclusion criteria were: active cancer, chronic inflammatory diseases. Serum levels of cholesterol-adjusted vitamin E were measured at baseline and bleeding events were recorded. Bleeding events were classified according to ISTH criteria.
RESULTS: Mean age was 73.6±9 years, 238 (59%) patients were male. Mean percent time in therapeutic INR range (TTR) was 65±16.4%. Bleeding events occurred in 81 (20%) patients (65 minor and 16 major bleedings). Cerebral bleeding occurred in 4 patients (0.98%). TTR was 64.7% in patients without bleeding and 64% (p=0.77) in those with bleeding. Time above therapeutic range was 13.6% in patients without bleeding and 12.1% in those with bleeding (p=0.27). Higher mean vitamin E levels were found in patients who experienced bleeding events compared to those who did not (5.1±1.8 µmol/mmol vs. 4.3±1.9 µmol/mmol; p=0.002).A progressive increase of serum Vitamin E from patients without bleeding (4.3±1.9 µmol/mmol) to those with minor (4.9±1.8 µmol/mmol) and major bleedings (5.6±1.8 µmol/mmol) was observed (ANOVA test: p=0.006). Kaplan-Meier analyses showed that highest quartile (>5.4 µmol/mmol) of vitamin E was associated to bleeding events compared to the lowest quartile (<3.2 µmol/mmol) (log-rank test: p=0.004). Using a Cox proportional hazard model vitamin E predicted bleeding events (HR 1.3; 95% CI: 1.1-1.6; p=0.009 for each increasing quartile of vitamin E) after adjusting for age, gender, BMI, previous ischemic stroke and TIA, previous myocardial infarction, diabetes, concomitant therapies, TTR and time above therapeutic range.
CONCLUSION: In NVAF serum vitamin E levels progressively increase from patients without to those with minor and major bleedings. Vitamin E serum levels can be a useful tool to stratify bleeding risk in patients receiving OAT.
- © 2012 by American Heart Association, Inc.