[Collins blood diluting reperfusion--an effective measure of controlled reperfusion for the heart hypothermically preserved for 24 hours in modified Collins solution].

: Controlled reperfusion is assumed to provide an appropriate environment surrounding the ischemic cardiac tissue at the initial reperfusion phase. Hence, this procedure might play a key role in resuscitating the long term preserved hearts. This study was designed to assess the efficacy of the newly devised reperfusion method; namely Collins Blood Diluting Reperfusion (CBDR), for those hearts subjected to 24-hours cold (4 degrees C) storage in modified Collins (MC) solution. Coronary reperfusion is commenced with the MC solution, and the oxygenated blood is successively added to dilute this perfusate with gradual rewarming under controlled perfusion pressure. Initial reperfusate, therefore, is supposed to be a blood cardioplegia with low Ca2+ and high Mg2+ content. During this procedure, any difference in the ionic composition between the storage solution and the reperfusate is completely abolished and myocardium is free from hastiness of temperature elevation. Using an isolated isovolum contracting heart prepared with an ex vivo apparatus incorporating a support dog, each heart was reperfused by unmodified blood (Group I: n = 7) or CBDR method (Group II: n = 10) under equally controlled low perfusion pressure. There was no difference in the myocardial creatine phosphate level between the 2 groups. However, the adenosine triphosphate content, which had been depleted to 30% of the preischemic level during the 24-hour preservation period, was restored to 52.0% after CBDR procedure (p less than 0.01) and consequently to 57.9% of the control at 60 minutes after reperfusion. Group I showed a significantly lower repletion effect at this phase (41.2% control; p less than 0.05 versus group II).(ABSTRACT TRUNCATED AT 250 WORDS)