Venous Thromboembolism Leg Exam (IMAGE) McMaster University Caption An international study of 3,396 patients with venous thromboembolism in 31 countries shows that the blood thinner rivaroxaban is just as safe as aspirin and more effective at preventing blood clots. Credit The Ottawa Hospital Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.