The RATIO Study is a multicenter, nationwide, randomized, controlled, single blinded,
unfunded trial of n. 900 patients undergoing multivessel OPCAB (≥2 grafts). This study is
designed to test in patients undergoing off-pump coronary artery bypass surgery the
hypothesis that full (high dose, 300 U/kg) and half (low dose,150 U/kg) heparinization are
not different in terms of thrombotic complications and major perioperative bleeding events
(null hypothesis).