[Effects of active synchronized prolonged coronary perfusion in the animal]

The efficacy of a system of active diastolic synchronised coronary perfusion was studied during prolonged balloon angioplasty in 8 sheep. In the first part of the study (group 1) including 5 animals, the aim was to study the effects of high and constant flow (48 ml/min) for 90 minutes perfusion on haemolysis, the arterial wall and the perfused myocardium. The second part of the study (group 2), including 3 animals, assessed whether flow adapted to the extent of the vascular bed perfused (24 to 40 ml/min) could protect the myocardium for an interval of 60 minutes. In group 1, after 90 minutes of perfusion (48 ml/min), there was no haemolysis, or jet lesion of the arterial wall distal to the catheter tip. On the other hand, the creatinine phosphokinase levels increased at the 60th minute (188 vs 119 i.u./l for controls) and at the 90th minute (238 vs 119 i.u./l; p < 0.05). Moreover, the perfused myocardium was the site of histological lesions. These observations showed myocardial changes due to the "overflow phenomenon". In group 2, the flow rate was adapted to each animal, increasing progressively until disappearance of electrocardiographic signs of ischaemia (ST elevation) and maintained for 60 minutes. No signs of haemolysis, jet lesions or myocardial changes were observed, with absence of creatinine phosphokinase elevation and histological abnormalities. These preliminary results show that the system investigated allowed myocardial protection after arterial occlusion for an interval of 60 minutes.