Importance of edema and compliance changes during 24 hours of preservation of the dog heart.

The development of myocardial edema and the changes in compliance during long-term preservation and reperfusion of 10 dog hearts were studied. Krebs solution, modified by the addition of potassium chloride (20 mEq/L), was used for 24 hours of low-pressure perfusion (15 mm Hg), at 4 degrees C. The hearts then were reperfused with the use of a support dog. Gravimetric heart water of myocardial biopsy tissue increased from control values of 78.0 +/- 0.8 to 82.8 +/- 0.6 ml/100 gm at 1 hour (p less than 0.01) and to 84.2 +/- 0.3 ml/100 gm after 24 hours of preservation (p less than 0.05 compared to 1 hour). After reperfusion, heart water decreased to 82.8 +/- 0.3 ml/100 gm (p less than 0.05). Passive compliance during preservation, obtained using an inflatable intraventricular balloon, decreased from 1.49 +/- 0.03 ml/mm Hg at 1 hour to 0.65 +/- 0.14 ml/mm Hg at 24 hours (p less than 0.05). High-energy phosphate levels were unchanged at 1 and 24 hours of preservation. Light and electron microscopy at 24 hours of preservation showed marked pericapillary edema and excellent preservation of intracellular structures. During reperfusion, ventricular function curves and dp/dt (2,841 +/- 581 mm Hg/sec) were comparable to previously reported control values. Passive compliance at 24 hours correlated with the diastolic compliance during reperfusion (p less than 0.01). The change in passive compliance during preservation also correlated with the change in coronary vascular resistance, a previously reported index of myocardial viability (p less than 0.05). This study has shown that the change in passive compliance of the heart during perfusion correlates with the adequacy of myocardial preservation and provides an additional index of preserved heart viability.