Although cardioplegia is limited to 4 hours of ice storage, University of Wisconsin solution has successfully extended this period to approximately 12 hours. In this study we have substituted polyethylene glycol for hydroxyethyl starch in a simplified University of Wisconsin solution (Cardiosol). Rabbit hearts were ice stored for 24 hours at 0 degrees C in either University of Wisconsin solution or Cardiosol (containing either 5% or 10% polyethylene glycol). Fresh control hearts were tested immediately after cardiectomy. Function was evaluated in an in vitro working heart model for 1 hour with aortic afterload at 100 cm H2O. Total cardiac output or the proportion of hearts reaching 100 cm H2O were compared. Hearts stored in University of Wisconsin solution for 24 hours functioned at 6% of control levels at 15 minutes of observation. None reached 100 cm H2O or deteriorated further with time (p < 0.05). By contrast, hearts stored in 5% Cardiosol showed progressive recovery during the 1-hour observation. Of the 13 hearts, 11 reached 100 cm H2O with a mean cardiac output of 51% of the control value. Increasing the concentration of polyethylene glycol to 10% improved cardiac output at all observation times, reaching 80% of control heart performance at 1 hour (control > 10% > 5% > University of Wisconsin solution [p < 0.05]). We concluded that 10% polyethylene glycol significantly improved 24-hour ice storage and, hence, viability to a functional level that matched our previously reported microperfusion results.

Adenosine↗

PubMedDate not supplied

Cardiotonic effects of reduced sulfhydryl amines after preservation of rabbit hearts.

This investigation was designed to examine the role of glutathione and other reduced sulfhydryl amines during reperfusion of the ischemic rabbit heart. To identify the biochemical features of reduced sulfhydryl amines contributing toward improved myocardial function, we investigated several chemical agents sharing a common property with glutathione (L-leucine, L-glycine, ascorbate, oxidized glutathione, L-cysteine). After a period of 24-hour hypothermic storage of the rabbit heart in a modified University of Wisconsin solution containing polyethylene glycol, the hearts were functionally evaluated on a Langendorff working heart model. The agents were then injected as a bolus (60 mumol/L) during reperfusion, and coronary flow and aortic output were measured. Control hearts were untreated. Reduced sulfhydryl amines (glutathione, L-cysteine) significantly improved coronary flow (p < 0.005) and cardiac output (p < 0.005). Ascorbate, L-leucine, L-glycine, and oxidized glutathione all failed to influence cardiac function.

Animals↗