Donor heart preservation with the potassium channel opener pinacidil: Comparison with University of Wisconsin and St. Thomas' solution

Background: Hyperpolarized arrest with the potassium channel opener pinacid il has been shown to provide effective myocardial protection during short-t erm global ischemia. This study tested the hypothesis that pinacidil may pr ovide effective long-term protection for heart transplant preservation. Methods: Four concentrations of pinacidil (50 mu M, 100 mu M. 0.5 mM, 1.0 m M) mixed in Krebs-Henseleit solution were compared with University of Wisco nsin and St. Thomas' Hospital solutions in a Krebs-Henseleit perfused rabbi t Langendorff model (n = 6 for each group). Hearts underwent 4 hours of hyp othermic (4 degrees C) storage, Over a wide range of volumes, left ventricu lar systolic function, diastolic compliance, and coronary flow were measure d prior to and following storage. Time to mechanical and electrical arrest, and post-ischemic percent tissue water were also measured. Results: Pinacidil 0.5 mM provided the best preservation of post-ischemic s ystolic function and coronary flow compared with the other pinacidil concen trations and was statistically equivalent to St. Thomas' solution in terms of post-ischemic systolic, diastolic, and flow properties. However, hearts protected with University of Wisconsin solution had significantly better pr eservation of systolic function and coronary flow. Conclusions: This investigation demonstrated that pinacidil in Krebs-Hensel eit solution possesses efficacy in long-term donor heart preservation. Pina cidil was equivalent to St. Thomas' solution but inferior to University of Wisconsin solution. Hyperpolarized arrest with potassium channel openers ma y be a novel strategy to improve donor heart preservation.