The influence of the no-reflow phenomenon on reperfusion and reoxygenation damage and enzyme release from anoxic and ischaemic isolated rat hearts.

Eighty isolated rat heart preparations were used to study relationships among creatine kinase (CK) release, the loss of vascular competence (no-reflow), and the distribution of morphological changes across the left ventricular wall which occur during 60 min global ischaemia or anoxia and following subsequent oxygenated reperfusion. Hearts were either fixed with glutaraldehyde for light and electron microscopy or were injected with 1% fluorescein to define the distribution of perfusable vessels. The extent of no-reflow in half of the hearts was reduced experimentally by maintaining the diastolic volume of the left ventricular lumen during ischaemia and anoxia with a water-filled balloon. The amount of CK released during 20 min of reoxygenation or reperfusion was inversely proportional to the extent of the no-reflow area observed just prior to reoxygeneration, and also reflected the transmural extent and the severity of myocardial cell damage. Extensive contraction band necrosis was only observed in reperfused regions of anoxic hearts. In isovolumic hearts reoxygenation caused no-reflow to develop in the ventricular myocardium, and this appeared to be associated with hypercontraction. Thus the no-reflow phenomenon has a profound effect on the transmural distribution of myocardial cell damage and enzyme release which follows post ischaemic reperfusion and post anoxic reoxygenation.