The purpose of this study is to evaluate the clinical efficacy of LeGoo™ as compared to a traditional vessel loop. LeGoo is a device that is intended to be used during surgical procedures to temporarily occlude blood vessels while forming an anastomosis. LeGoo™ will be evaluated in subjects undergoing off-pump coronary artery by-pass (OPCAB) surgery. This is a prospective, randomized trial with a 30-day follow-up period. Half of the eligible patients will be randomized to the experimental group (LeGoo™); and the other half to the control group (standard vessel loops).