BACKGROUND: Mild hypothermia confers a myocardial protective effect that may make it a useful adjunct to reperfusion therapy for myocardial infarction (MI). The effect of temperature on the extent and distribution of myocardial reperfusion injury in a collateral deficient ovine model was studied. METHODS: Topical cooling maintained left atrial temperature at 39.5 degrees C (n = 8), 38.5 degrees C (n = 5), 37.5 degrees C (n = 6), 36.5 degrees C (n = 6), or 35.5 degrees C (n = 5) in sheep prior to 1 hour of coronary occlusion to produce an anteroapical myocardial risk area (AR) followed by 3 hours of reperfusion. A dual staining and planimetry technique was used to assess infarct size as a percentage of the AR in 3 myocardial short axis slices that included the entire AR (slice 1= most apical; slice 3= most basal). The subendocardial, midmyocardial, and subepicardial extent in short axis of the infarct was also assessed in each slice. Microspheres assessed transmural blood flow. RESULTS: At 39.5 degrees C there was a long-axis gradient in myocardial injury that was most severe at the apex and lessened toward the base. The midmyocardial region was most susceptible to injury at all long axis levels. Temperature reduction (as little as 1 degrees C) was associated with improved salvage that was most pronounced in the apical subendocardium and least in the basilar midmyocardium. Reperfusion at 39.5 degrees C resulted in severe transmural microvascular injury (no-reflow) that was completely obviated at temperatures below 38.5 degrees C. CONCLUSIONS: Myocardial reperfusion injury varies over the long and short LV axes. Mild hypothermia preferentially improves myocardial salvage at the LV apex. Small temperature changes can dramatically affect microvascular integrity.
BACKGROUND: Mild hypothermia confers a myocardial protective effect that may make it a useful adjunct to reperfusion therapy for myocardial infarction (MI). The effect of temperature on the extent and distribution of myocardial reperfusion injury in a collateral deficient ovine model was studied. METHODS: Topical cooling maintained left atrial temperature at 39.5 degrees C (n = 8), 38.5 degrees C (n = 5), 37.5 degrees C (n = 6), 36.5 degrees C (n = 6), or 35.5 degrees C (n = 5) in sheep prior to 1 hour of coronary occlusion to produce an anteroapical myocardial risk area (AR) followed by 3 hours of reperfusion. A dual staining and planimetry technique was used to assess infarct size as a percentage of the AR in 3 myocardial short axis slices that included the entire AR (slice 1= most apical; slice 3= most basal). The subendocardial, midmyocardial, and subepicardial extent in short axis of the infarct was also assessed in each slice. Microspheres assessed transmural blood flow. RESULTS: At 39.5 degrees C there was a long-axis gradient in myocardial injury that was most severe at the apex and lessened toward the base. The midmyocardial region was most susceptible to injury at all long axis levels. Temperature reduction (as little as 1 degrees C) was associated with improved salvage that was most pronounced in the apical subendocardium and least in the basilar midmyocardium. Reperfusion at 39.5 degrees C resulted in severe transmural microvascular injury (no-reflow) that was completely obviated at temperatures below 38.5 degrees C. CONCLUSIONS:Myocardial reperfusion injury varies over the long and short LV axes. Mild hypothermia preferentially improves myocardial salvage at the LV apex. Small temperature changes can dramatically affect microvascular integrity.
Authors: Benjamin M Jackson; Joseph H Gorman; Ivan S Salgo; Sina L Moainie; Theodore Plappert; Martin St John-Sutton; L Henry Edmunds; Robert C Gorman Journal: Am J Physiol Heart Circ Physiol Date: 2002-10-31 Impact factor: 4.733
Authors: J A Ambrose; M A Tannenbaum; D Alexopoulos; C E Hjemdahl-Monsen; J Leavy; M Weiss; S Borrico; R Gorlin; V Fuster Journal: J Am Coll Cardiol Date: 1988-07 Impact factor: 24.094
Authors: L J Markovitz; E B Savage; M B Ratcliffe; J E Bavaria; G Kreiner; R V Iozzo; W C Hargrove; D K Bogen; L H Edmunds Journal: Ann Thorac Surg Date: 1989-12 Impact factor: 4.330
Authors: Hirotsugu Hamamoto; Hiroaki Sakamoto; Bradley G Leshnower; Landi M Parish; Shinya Kanemoto; Robin Hinmon; Theodore Plappert; Shinji Miyamoto; Martin G St John-Sutton; Joseph H Gorman; Robert C Gorman Journal: Ann Thorac Surg Date: 2009-01 Impact factor: 4.330
Authors: Rutger H Stoffers; Marie Madden; Mohammed Shahid; Francisco Contijoch; Joseph Solomon; James J Pilla; Joseph H Gorman; Robert C Gorman; Walter R T Witschey Journal: J Cardiovasc Magn Reson Date: 2017-02-15 Impact factor: 5.364
Authors: Brianna F Moon; Srikant Kamesh Iyer; Eileen Hwuang; Michael P Solomon; Anya T Hall; Rishabh Kumar; Nicholas J Josselyn; Elizabeth M Higbee-Dempsey; Andrew Tsourkas; Akito Imai; Keitaro Okamoto; Yoshiaki Saito; James J Pilla; Joseph H Gorman; Robert C Gorman; Cory Tschabrunn; Samuel J Keeney; Estibaliz Castillero; Giovanni Ferrari; Steffen Jockusch; Felix W Wehrli; Haochang Shou; Victor A Ferrari; Yuchi Han; Avanti Gulhane; Harold Litt; William Matthai; Walter R Witschey Journal: Nat Commun Date: 2020-06-29 Impact factor: 14.919