Control of anticoagulation with vitamin K antagonists: overestimation of median time in therapeutic range when assessed by linear interpolation

Meta-Analysis Comparing Dual Versus Single Antiplatelet Therapy in Combination With Antithrombotic Therapy in Patients With Atrial Fibrillation Who Underwent Percutaneous Coronary Intervention With Stent Implantation

The coexistence of atrial fibrillation and coronary artery disease is commonly found in clinical practice. The aim of this meta-analysis is to compare the clinical efficacy and safety of dual versus single antiplatelet therapy in combination with antithrombotic therapy in patients with atrial fibrillation undergoing percutaneous coronary intervention. PubMed, EMBASE and Web of Science databases were systematically evaluated for articles published up to October 31, 2017. The risk ratios (RR) were extracted from each study. Pooled estimates with corresponding 95% confidence intervals (CI) were estimated by a fixed or random-effects model. Eight studies involving a total of 10,861 patients with atrial fibrillation were included in this meta-analysis. Five thousand sixty-six participants received dual antiplatelet therapy together with warfarin or new oral anticoagulation (triple antithrombotic therapy, TT) and 5,795 participants received single antiplatelet therapy together with warfarin or new oral anticoagulation (dual antithrombotic therapy). TT was associated with a significantly higher incidence of all (RR 1.45, p <0.001) and major (RR 1.77, p <0.001) bleeding events, but no difference with regard to stroke, in-stent thrombosis, major adverse cardiovascular events, and all-cause mortality rate. In conclusion, as compared to TT, dual antithrombotic therapy is equally effective in reducing stroke, in-stent thrombosis, major adverse cardiovascular events, and all-cause mortality rate, but shows beneficial effect in reducing overall bleeding incidence in atrial fibrillation patients who underwent percutaneous coronary intervention.

Monitoring of treatment with vitamin K antagonists: recombinant thromboplastins are more sensitive to factor VII than tissue-extract thromboplastins

Essentials Differences in sensitivity to factor VII (FVII) have been suggested between thromboplastins. FVII-induced International Normalized Ratio (INR) changes differ between commercial reagents. Recombinant human thromboplastins are more sensitive to FVII than tissue-extract thromboplastins. Thromboplastin choice may affect FVII-mediated INR stability.

SUMMARY

Background Differences regarding sensitivity to factor VII have been suggested for recombinant human and tissue-extract thromboplastins used for International Normalized Ratio (INR) measurement, but the evidence is scarce. Differences in FVII sensitivity are clinically relevant, as they can affect INR stability during treatment with vitamin K antagonists (VKAs). Objectives To determine whether commercial thromboplastins react differently to changes in FVII. Methods We studied the effect of addition of FVII on the INR in plasma by using three tissue-extract (Neoplastin C1+, Hepato Quick, and Thromborel S) and three recombinant human (Recombiplastin 2G, Innovin, and CoaguChek XS) thromboplastins. Three different concentrations of purified human FVII (0.006, 0.012 and 0.062 μg mL-1 plasma), or buffer, were added to five certified pooled plasmas of patients using VKAs (INR of 1.5-3.5). Changes in FVII activity were measured with two bioassays (Neoplastin and Recombiplastin), and relative INR changes were compared between reagents. Results After addition of 0.062 μg mL-1 FVII, FVII activity in the pooled plasmas increased by approximately 20% (Neoplastin) or 32% (Recombiplastin) relative to the activity in pooled normal plasma. All thromboplastins showed dose-dependent INR decreases. The relative INR change in the pooled plasmas significantly differed between the six thromboplastins. No differences were observed among recombinant or tissue-extract thromboplastins. Pooled results indicated that the FVII-induced INR change was greater for recombinant than for tissue-extract thromboplastins. Conclusions Differences regarding FVII sensitivity exist between various thromboplastins used for VKA monitoring. Recombinant human thromboplastins are more sensitive to FVII than tissue-extract thromboplastins. Therefore, thromboplastin choice may affect FVII-mediated INR stability.