Eitaro Kodani1, Hirotsugu Atarashi2, Hiroshi Inoue3, Ken Okumura4, Takeshi Yamashita5, Hideki Origasa6. 1. Department of Internal Medicine and Cardiology, Nippon Medical School, Tama-Nagayama Hospital, Tokyo, Japan. Electronic address: kodani@nms.ac.jp. 2. Department of Internal Medicine and Cardiology, Nippon Medical School, Tama-Nagayama Hospital, Tokyo, Japan. 3. Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan. 4. Department of Cardiology, Respiratory Medicine and Nephrology, Hirosaki University Graduate School of Medicine, Aomori, Japan. 5. The Cardiovascular Institute, Tokyo, Japan. 6. Division of Biostatistics and Clinical Epidemiology, University of Toyama, Toyama, Japan.
Abstract
BACKGROUND: Prior ischemic stroke or transient ischemic attack (TIA) is a high risk for thromboembolism in patients with nonvalvular atrial fibrillation (NVAF). To clarify rates of thromboembolic and hemorrhagic events, and target intensities of warfarin for secondary prevention, a subanalysis was performed using data from the J-RHYTHM Registry. METHODS: Of 7937 outpatients with atrial fibrillation, 7406 with NVAF (men 70.8%, 69.8 ± 10.0 years) were followed for 2 years or until an event occurred. Event rates and effect of warfarin were compared between patients with (secondary prevention) and without (primary prevention) prior stroke/TIA. RESULTS: Prevalence of male sex, diabetes mellitus, and mean age were higher in the secondary prevention group, showing a higher CHADS2 (congestive heart failure, hypertension, age 75 years or older, diabetes mellitus, and history of stroke or TIA) score than the primary prevention group (3.5 ± 1.0 versus 1.4 ± 1.0, P < .001). In the secondary prevention group, 93.4% of patients received warfarin and their time in therapeutic range was 62.8%. During follow-up, thromboembolism occurred more frequently in the secondary than in the primary prevention group (2.8% versus 1.5%, P = .004), especially in patients without warfarin. Major hemorrhage also occurred more frequently in the secondary prevention group (3.0% versus 1.7%, P = .006). Compared with patients not taking warfarin, combined rates of both events were lower at an international normalized ratio (INR) of 1.6-2.59 in patients taking warfarin in the secondary as well as in the primary prevention groups. CONCLUSIONS: Both thromboembolism and major hemorrhage occurred more frequently in NVAF patients with prior ischemic stroke/TIA. Target INR should be 1.6-2.59 for secondary as well as primary prevention of thromboembolism in Japanese NVAF patients.
BACKGROUND: Prior ischemic stroke or transient ischemic attack (TIA) is a high risk for thromboembolism in patients with nonvalvular atrial fibrillation (NVAF). To clarify rates of thromboembolic and hemorrhagic events, and target intensities of warfarin for secondary prevention, a subanalysis was performed using data from the J-RHYTHM Registry. METHODS: Of 7937 outpatients with atrial fibrillation, 7406 with NVAF (men 70.8%, 69.8 ± 10.0 years) were followed for 2 years or until an event occurred. Event rates and effect of warfarin were compared between patients with (secondary prevention) and without (primary prevention) prior stroke/TIA. RESULTS: Prevalence of male sex, diabetes mellitus, and mean age were higher in the secondary prevention group, showing a higher CHADS2 (congestive heart failure, hypertension, age 75 years or older, diabetes mellitus, and history of stroke or TIA) score than the primary prevention group (3.5 ± 1.0 versus 1.4 ± 1.0, P < .001). In the secondary prevention group, 93.4% of patients received warfarin and their time in therapeutic range was 62.8%. During follow-up, thromboembolism occurred more frequently in the secondary than in the primary prevention group (2.8% versus 1.5%, P = .004), especially in patients without warfarin. Major hemorrhage also occurred more frequently in the secondary prevention group (3.0% versus 1.7%, P = .006). Compared with patients not taking warfarin, combined rates of both events were lower at an international normalized ratio (INR) of 1.6-2.59 in patients taking warfarin in the secondary as well as in the primary prevention groups. CONCLUSIONS: Both thromboembolism and major hemorrhage occurred more frequently in NVAF patients with prior ischemic stroke/TIA. Target INR should be 1.6-2.59 for secondary as well as primary prevention of thromboembolism in Japanese NVAF patients.