The Ottawa Hospital Mar 11 2026 The first clinical trial to compare two commonly used drugs head-to-head for venous thrombosis treatment has found a clear winner: while both drugs work well to prevent recurrent blood clots, apixaban is safer than rivaroxaban, with fewer bleeding complications. Venous thrombosis occurs when a blood clot lodges in the veins of the legs or lungs. It is the third leading cause of cardiovascular death after heart attack and stroke and is the most common preventable