https://journal.chestnet.org/article/S0012-3692(08)60117-8/pdf

Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition).

https://journal.chestnet.org/article/S0012-3692(12)60119-6/pdf

Oral Anticoagulant Therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140673610611944.pdf

Efficacy and safety of dabigatran compared with warfarin at different levels of international normalised ratio control for stroke prevention in atrial fibrillation: An analysis of the RE-LY trial

https://journal.chestnet.org/article/S0012-3692(12)60131-7/pdf

Antithrombotic Therapy for Atrial Fibrillation: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

Background— Oral anticoagulation (OAC) therapy is effective in atrial fibrillation but requires vigilance to maintain the international normalized ratio in the therapeutic range. This report examines how differences in time in therapeutic range (TTR) between centers and between countries affect the outcomes of OAC therapy. Methods and Results— In a posthoc analysis, the TTRs of patients on OAC in a randomized trial of OAC versus clopidogrel plus aspirin (Atrial Fibrillation Clopidogrel Trial With Irbesartan for Prevention of Vascular Events [ACTIVE W]) were used to calculate the mean TTR for each of 526 centers and 15 countries. Proportional-hazards analysis, with and without adjustment for baseline variables, was performed, with patients stratified by TTR quartile and country. A wide variation in TTRs was found between centers, with mean TTRs for centers in the 4 quartiles of 44%, 60%, 69%, and 78%. For patients at centers below the median TTR (65%), no treatment benefit was demonstrated as measured by r...

Benefit of Oral Anticoagulant Over Antiplatelet Therapy in Atrial Fibrillation Depends on the Quality of International Normalized Ratio Control Achieved by Centers and Countries as Measured by Time in Therapeutic Range

Background Warfarin sodium reduces stroke risk in patients with atrial fibrillation, but international normalized ratio (INR) monitoring is required. Target INRs are frequently not achieved, and the risk of death, bleeding, myocardial infarction (MI), and stroke or systemic embolism event (SEE) may be related to INR control. Methods We analyzed the relationship between INR control and the rates of death, bleeding, MI, and stroke or SEE among 3587 patients with atrial fibrillation randomized to receive warfarin treatment in the SPORTIF (Stroke Prevention Using an Oral Thrombin Inhibitor in Atrial Fibrillation) III and V trials. The mean±SD follow-up was 16.6 ± 6.3 months. Patients were divided into 3 equal groups (those with good control [>75%], those with moderate control [60%-75%], or those with poor control [ Results The poor control group had higher rates of annual mortality (4.20%) and major bleeding (3.85%) compared with the moderate control group (1.84% and 1.96%, respectively) and the good control group (1.69% and 1.58%, respectively) ( P P  = .04) and of stroke or SEE (2.10% vs 1.07%, P  = .02). Conclusions In patients with atrial fibrillation taking warfarin, the risks of death, MI, major bleeding, and stroke or SEE are related to INR control. Good INR control is important to improve patient outcomes.

https://jamanetwork.com/journals/jamainternalmedicine/articlepdf/411636/ioi60188_239_245.pdf

Comparison of Outcomes Among Patients Randomized to Warfarin Therapy According to Anticoagulant Control: Results From SPORTIF III and V

Background: Warfarin sodium reduces stroke risk in patients with atrial fibrillation, but international normalized ratio (INR) monitoring is required. Target INRs are frequently not achieved, and the risk of death, bleeding, myocardial infarction (MI), and stroke or systemic embolism event (SEE) may be related to INR control. Methods: We analyzed the relationship between INR control and the rates of death, bleeding, MI, and stroke or SEE among 3587 patients with atrial fibrillation randomized to receive warfarin treatment in the SPORTIF (Stroke Prevention Using an Oral Thrombin Inhibitor in Atrial Fibrillation) III and V trials. The mean±SD follow-up was 16.6±6.3 months. Patients were divided into 3 equal groups (those with good control [75%], those with moderate control [60%-75%], or those with poor control [60%]) according to the percentage time with an INR of 2.0 to 3.0. Outcomes were compared according to INR control. The main outcome measures were death, bleeding, MI, and stroke or SEE. Results:The poor control group had higher rates of annualmortality(4.20%)andmajorbleeding(3.85%)comparedwiththemoderatecontrolgroup(1.84%and1.96%, respectively) and the good control group (1.69% and 1.58%, respectively) (P.01 for all). Compared with the good control group, the poor control group had higher ratesofMI(1.38%vs0.62%,P=.04)andofstrokeorSEE (2.10% vs 1.07%, P=.02). Conclusions: In patients with atrial fibrillation taking warfarin,therisksofdeath,MI,majorbleeding,andstroke or SEE are related to INR control. Good INR control is important to improve patient outcomes.

Jan Feyzi

Papers

Comparison of Outcomes Among Patients Randomized to Warfarin Therapy According to Anticoagulant Control: Results From SPORTIF III and V

Comparison of Outcomes Among Patients Randomized to Warfarin Therapy According to Anticoagulant Control