Temporary coronary artery occlusion during off-pump coronary artery bypass grafting with the new poloxamer P407 does not cause endothelial dysfunction in epicardial coronary arteries.
OBJECTIVE
The aim of this study was to assess the efficacy of the novel reversible thermosensitive gel poloxamer 407 for occlusion of the coronary vessel necessary for minimally invasive operations and its effects on coronary endothelium.


METHODS
Domestic swine were submitted to occlusion of the left anterior descending or right coronary artery using the poloxamer. The left and right internal thoracic arteries were used as grafts to perform coronary artery bypasses. Animals were humanely killed after 3 hours of perfusion (acute; n = 8) or 3 days (subacute; n = 6). The vascular reactivity of coronary artery was evaluated in response to serotonin and bradykinin. Histologic studies were performed to analyze cardiomyocyte necrosis and endothelial coverage.


RESULTS
The gel led to an occlusion of 7.8 +/- 2.2 minutes. Concentration-response curves of occluded coronary segments showed no difference of endothelium-dependent relaxations in both operated groups (P < .05 vs control). Histologic studies demonstrated the absence of cardiomyocyte necrosis after coronary artery occlusion in the acute group; a small infarct zone was detected in 1 animal in the subacute group, resulting from an occlusion of the first diagonal branch. The endothelial layer coverage was preserved in both groups.


CONCLUSIONS
The poloxamer 407 represents a promising technique for obtaining hemostasis at the site of anastomosis during construction of bypasses during beating heart coronary artery surgery, without damage to the endothelium or ischemic consequence.
Bouchot
Olivier
O
Department of Cardiovascular Surgery, Le Bocage Hospital, Dijon, France.
Aubin
Marie-Claude
MC
Carrier
Michel
M
Cohn
William E
WE
Perrault
Louis P
LP
D000714:Anastomosis, Surgical; D000818:Animals; D047549:Coronary Artery Bypass, Off-Pump; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000187:drug effects* / Q000601:surgery; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects; D005260:Female; D005782:Gels; D006488:Hemostasis, Surgical / Q000379:methods*; D007387:Internal Mammary-Coronary Artery Anastomosis; D008297:Male; D008955:Models, Cardiovascular; D010496:Pericardium; D020442:Poloxamer / Q000494:pharmacology*; D013501:Surface-Active Agents / Q000494:pharmacology*; D013552:Swine; D016896:Treatment Outcome; D014652:Vascular Diseases / Q000209:etiology; D014664:Vasodilation / Q000187:drug effects
D005782:Gels; D013501:Surface-Active Agents; D020442:Poloxamer