OBJECTIVE: Reflow following coronary artery occlusion is an important predictor of clinical outcome. This study tests the effects of regional hypothermia, initiated late during ischemia and maintained for 2 h of reperfusion, on the no-reflow phenomenon. METHODS: Anesthetized, open-chest New Zealand White rabbits received 30 min of coronary artery occlusion and 3 h reperfusion. Regional myocardial hypothermia (H, n=14), starting 10 min before reperfusion and continuing for 2 h of reperfusion, was compared with normothermia (N, n=14). Regional myocardial blood flow (microspheres) was measured during occlusion and at the end of reperfusion. The anatomic zone of no-reflow (thioflavin S in vivo injection) and infarct size were measured in the ischemic risk region at the end of the study. RESULTS: Myocardial temperature in H rabbits was decreased by 5.0+/-0.4 degrees C from baseline (37.1+/-0.2 degrees C) and remained about 32 degrees C during the cooling phase, returning to 36.0+/-0.3 degrees C at 3 h. N hearts remained within 0.2 degrees C of baseline (37.3+/-0.1 degrees C) throughout. Both groups were equally ischemic during occlusion, but at the end of reperfusion reflow to the previously ischemic zone was significantly higher in H, 77+/-5% of normal blood flow versus 36+/-4% in N (P=0.0001). The zone of anatomic no-reflow was significantly smaller in H, 11+/-3% of the ischemic risk zone versus 37+/-3% in N (P=0.0001), and was proportionally smaller when represented as a percent of the necrotic zone 36+/-6% compared with 75+/-5% in N. Infarct size, expressed as a percent of the ischemic risk zone was significantly smaller in H vs. N hearts (27+/-4 and 51+/-5%, P=0.0000). CONCLUSION: This study shows that hypothermic therapy initiated late during ischemia and continuing for several hours of reperfusion significantly improves reflow and reduces macroscopic zones of no-reflow and necrosis in this model. The improvement in reflow was greater than would be expected in the H group compared with N, based on the extent of necrosis. As reflow is a predictor of outcome, this intervention may have clinical implications.
OBJECTIVE: Reflow following coronary artery occlusion is an important predictor of clinical outcome. This study tests the effects of regional hypothermia, initiated late during ischemia and maintained for 2 h of reperfusion, on the no-reflow phenomenon. METHODS: Anesthetized, open-chest New Zealand White rabbits received 30 min of coronary artery occlusion and 3 h reperfusion. Regional myocardial hypothermia (H, n=14), starting 10 min before reperfusion and continuing for 2 h of reperfusion, was compared with normothermia (N, n=14). Regional myocardial blood flow (microspheres) was measured during occlusion and at the end of reperfusion. The anatomic zone of no-reflow (thioflavin S in vivo injection) and infarct size were measured in the ischemic risk region at the end of the study. RESULTS: Myocardial temperature in H rabbits was decreased by 5.0+/-0.4 degrees C from baseline (37.1+/-0.2 degrees C) and remained about 32 degrees C during the cooling phase, returning to 36.0+/-0.3 degrees C at 3 h. N hearts remained within 0.2 degrees C of baseline (37.3+/-0.1 degrees C) throughout. Both groups were equally ischemic during occlusion, but at the end of reperfusion reflow to the previously ischemic zone was significantly higher in H, 77+/-5% of normal blood flow versus 36+/-4% in N (P=0.0001). The zone of anatomic no-reflow was significantly smaller in H, 11+/-3% of the ischemic risk zone versus 37+/-3% in N (P=0.0001), and was proportionally smaller when represented as a percent of the necrotic zone 36+/-6% compared with 75+/-5% in N. Infarct size, expressed as a percent of the ischemic risk zone was significantly smaller in H vs. N hearts (27+/-4 and 51+/-5%, P=0.0000). CONCLUSION: This study shows that hypothermic therapy initiated late during ischemia and continuing for several hours of reperfusion significantly improves reflow and reduces macroscopic zones of no-reflow and necrosis in this model. The improvement in reflow was greater than would be expected in the H group compared with N, based on the extent of necrosis. As reflow is a predictor of outcome, this intervention may have clinical implications.
Authors: M Chenoune; F Lidouren; C Adam; S Pons; L Darbera; P Bruneval; B Ghaleh; R Zini; J-L Dubois-Randé; P Carli; B Vivien; J-D Ricard; A Berdeaux; R Tissier Journal: Circulation Date: 2011-08-01 Impact factor: 29.690
Authors: Renaud Tissier; Mourad Chenoune; Bijan Ghaleh; Michael V Cohen; James M Downey; Alain Berdeaux Journal: Cardiovasc Res Date: 2010-07-08 Impact factor: 10.787
Authors: Joanna M S Davies; Josiane Cillard; Bertrand Friguet; Enrique Cadenas; Jean Cadet; Rachael Cayce; Andrew Fishmann; David Liao; Anne-Laure Bulteau; Frédéric Derbré; Amélie Rébillard; Steven Burstein; Etienne Hirsch; Robert A Kloner; Michael Jakowec; Giselle Petzinger; Delphine Sauce; Florian Sennlaub; Isabelle Limon; Fulvio Ursini; Matilde Maiorino; Christina Economides; Christian J Pike; Pinchas Cohen; Anne Negre Salvayre; Matthew R Halliday; Adam J Lundquist; Nicolaus A Jakowec; Fatima Mechta-Grigoriou; Mathias Mericskay; Jean Mariani; Zhenlin Li; David Huang; Ellsworth Grant; Henry J Forman; Caleb E Finch; Patrick Y Sun; Laura C D Pomatto; Onnik Agbulut; David Warburton; Christian Neri; Mustapha Rouis; Pierre Cillard; Jacqueline Capeau; Jean Rosenbaum; Kelvin J A Davies Journal: Geroscience Date: 2017-12-21 Impact factor: 7.713