Use of the Purified Poloxamer 407 for Temporary Coronary Occlusion in Off-Pump CABG Does Not Cause Myocardial Injury

Abstract

Objective The new poloxamer 407 (LeGoo), a thermoreversible gel, previously showed efficiency in temporarily occluding coronary arteries and preserving endothelial function. However, its long-term effect on the myocardium after dissolution in bloodstream is uncertain. Methods Two groups of pigs (12 total) were compared after being submitted to a 10-minute coronary occlusion either with silastic loops (snare group) or with poloxamer 407 injection (P407 group). Reflow was procured by snare removal or P407 dissolution with topical cooling. Animals were kept alive for 3 days with creatine kinase-MB and troponin T (TnT) plasmatic measurement at 3 hours and 3 days after surgery, when they were killed for myocardial histopathologic study. Results Each animal survived during the study. Baseline plasmatic levels of cardiac enzymes were similar between both groups. No variation in creatine kinase-MB level throughout the study was seen in either group. A significant rise in TnT from baseline was noted 3 hours after reperfusion in both groups, with a peak level significantly lower in the P407 group (P < 0.05). TnT plasmatic levels returned to baseline level in both groups on the day the animals were killed (3 days). Histopathologic examinations of the stained myocardial samples showed no evidence of myocardial infarction either in the snare group or in the P407 group. Conclusions Poloxamer 407 does not cause myocardial damage after elimination in the bloodstream. The safety of this hemostatic device is now established, and application for FDA approval for human clinical studies is under way.