title: Reperfusate composition: interaction of marked hyperglycemia and marked hyperosmolarity in allowing immediate contractile recovery after four hours of regional ischemia.
abstract: This study tests the hypothesis that improved muscle salvage after prolonged ischemia (4 hours) occurs when the substrate-enriched blood cardioplegic solution is markedly hyperglycemic (greater than 400 mg/dl) and markedly hyperosmotic (greater than 400 mOsm). Thirty-five dogs underwent 4 hours of occlusion of the left anterior descending coronary artery and reperfusion during total vented bypass with substrate-enriched blood cardioplegic solution, in which the glucose concentration and osmolarity were varied in relation to one another. Spontaneous systolic shortening recovered consistently (31 +/- 6%) only when glucose was greater than 400 mg/dl and osmolarity was greater than 400 mOsm. The least recovery occurred (only one of six dogs recovering spontaneous shortening) when cardioplegic glucose was greater than 400 mg/dl and osmolarity was greater than 400 mOsm. Regional segments reperfused with our standard substrate-enriched blood cardioplegic solution had lower transmural flow rates following reperfusion (56 versus 87 ml/100 gm/min, p less than 0.05), markedly reduced mitochondrial State 3 and State 4 respiration in epicardial and endocardial muscle (p less than 0.05), and the most extensive histochemical evidence of damage (63% area of nonstaining versus area at risk, p less than 0.05). We conclude that markedly increased levels of osmolarity (greater than 400 mOsm) and glucose (greater than 400 mg/dl) improve the capacity of substrate-enriched blood cardioplegic solution to salvage myocardium after prolonged ischemia.
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000627:therapeutic use; D002951:Citrates / Q000627:therapeutic use; D019343:Citric Acid; D003067:Coenzymes; D003326:Coronary Circulation; D003327:Coronary Disease / Q000188:drug therapy* / Q000503:physiopathology; D004110:Diltiazem / Q000627:therapeutic use; D004285:Dogs; D005947:Glucose / Q000494:pharmacology / Q000627:therapeutic use*; D005971:Glutamates / Q000627:therapeutic use; D006324:Heart Arrest, Induced; D009200:Myocardial Contraction / Q000187:drug effects; D009994:Osmolar Concentration; D010710:Phosphates / Q000627:therapeutic use; D011188:Potassium / Q000627:therapeutic use; D014325:Tromethamine / Q000627:therapeutic use; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000627:therapeutic use
chemical_list: D002951:Citrates; D003067:Coenzymes; D005971:Glutamates; D010710:Phosphates; D014325:Tromethamine; D014451:Ubiquinone; D019343:Citric Acid; D001224:Aspartic Acid; D004110:Diltiazem; C024989:coenzyme Q10; D005947:Glucose; D011188:Potassium