For over two decades LMWHs have been routinely used to provide therapeutic coverage in patients who must temporarily stop warfarin. Current guidelines suggest using injectable anticoagulants during warfarin interruption (aka bridging) in patients with atrial fibrillation based on patients’ risk of arterial thrombosis. Using the CHADS2 score to assess risk, the guidelines recommend (grade 2C) bridge therapy if the CHADS2 score is 5 or higher and not bridging if the CHADS2 score is 2 or lower. But what about patients with a CHADS2 score of 3 or 4?