THE ADENOSINE-TRIPHOSPHATE-SENSITIVE POTASSIUM-CHANNEL OPENER PINACIDIL IS EFFECTIVE IN BLOOD CARDIOPLEGIA

Background. This study was designed to evaluate the adenosine-triphosp hate-sensitive potassium channel opener pinacidil as a blood cardiople gic agent. Methods. Using a blood-perfused, parabiotic, Langendorff ra bbit model, hearts underwent 30 minutes of normothermic ischemia prote cted with blood cardioplegia (St. Thomas' solution [n = 8] or Krebs-He nseleit solution with pinacidil [50 mu mol/L, n = 8]) and 30 minutes o f reperfusion. Percent recovery of developed pressure, mechanical arre st, electrical arrest, reperfusion ventricular fibrillation, percent t issue water, and myocardial oxygen consumption were compared. Results, The percent recovery of developed pressure was not different between the groups (52.3 +/- 5.9 and 52.8 +/- 6.9 for hyperkalemic and pinacid il cardioplegia, respectively). Pinacidil cardioplegia was associated with prolonged electrical and mechanical activity (14.4 +/- 8.7 and 6. 1 +/- 3.9 minutes), compared with hyperkalemic cardioplegia (1.1 +/- 0 .6 and 1.1 +/- 0.6 minutes, respectively; p < 0.05). Pinacidil cardiop legia was associated with a higher reperfusion myocardial oxygen consu mption (0.6 +/- 0.1 versus 0.2 +/- 0.0 mL/100 g myocardium/ beat; p < 0.05) and a higher percent of tissue water (79.6% +/- 0.7% versus 78.6 % +/- 1.2%; p < 0.05). Conclusions. Systolic recovery was not differen t between groups, demonstrating comparable effectiveness of pinacidil and hyperkalemic warm blood cardioplegia. (Ann Thorac Surg 1998;66:768 -73) (C) 1998 by The Society of Thoracic Surgeons.