Reperfusate composition: benefits of marked hypocalcemia and diltiazem on regional recovery.
This study tests the hypothesis that improved muscle salvage is possible by markedly reducing the ionic calcium (Ca++) of the reperfusate (less than 250 mumol/L) and adding a calcium channel-blocking drug (diltiazem). Preliminary pilot studies showed that a 20-minute infusion of markedly hypocalcemic substrate-enriched blood cardioplegic solution (less than 250 mumol/L Ca++) did not affect left ventricular function adversely and that a 150 to 250 mumol/L substrate-enriched blood cardioplegic solution, delivered during total vented bypass with diltiazem, 300 micrograms/kg body weight, produced the most consistent functional recovery and the least histochemical evidence of damage (triphenyltetrazolium chloride nonstaining) after 2 hours of regional ischemia. Experimental studies of 2 hours of regional ischemia were followed by either regional normocalcemic (1000 to 1200 mumol/L) blood cardioplegic reperfusion in bypassed hearts, with or without diltiazem, or hypocalcemic (150 to 150 mumol/L) blood cardioplegic reperfusion with diltiazem for 20 minutes. Results showed that hypocalcemic blood cardioplegic solution with diltiazem produced superior recovery of systolic shortening (58% versus 11% systolic shortening, p less than 0.05) and limitation of histochemical damage (11% versus 54%, p less than 0.05), in comparison with normocalcemic blood cardioplegic solution without diltiazem. These studies suggest that modifying the regional reperfusate by markedly reducing ionic calcium levels and adding calcium channel-blocking drugs is safe and may improve myocardial salvage more than using substrate-enriched blood cardioplegic solution alone.
D000818:Animals; D001224:Aspartic Acid / Q000627:therapeutic use; D001552:Benzazepines / Q000627:therapeutic use*; D002118:Calcium / Q000627:therapeutic use*; D003326:Coronary Circulation / Q000187:drug effects*; D003327:Coronary Disease / Q000188:drug therapy* / Q000503:physiopathology; D004110:Diltiazem / Q000627:therapeutic use*; D004285:Dogs; D005971:Glutamates / Q000627:therapeutic use; D006324:Heart Arrest, Induced; D006439:Hemodynamics; D011188:Potassium / Q000627:therapeutic use; D014325:Tromethamine / Q000627:therapeutic use
D001552:Benzazepines; D005971:Glutamates; D014325:Tromethamine; D001224:Aspartic Acid; D004110:Diltiazem; D011188:Potassium; D002118:Calcium