EFFECTS OF REDUCED RED-CELL DEFORMABILITY ON CORONARY HEMODYNAMICS AND CARDIAC-FUNCTION

To evaluate the effects of reduced red cell deformability on coronary hemodynamics and cardiac function, the coronary artery was perfused wi th blood containing partially hardened red cells pretreated with gluta raldehyde (gblood) in dogs. During 30 min of gblood perfusion, the cor onary flow(CF) decreased and the coronary vascular resistance (CVR) in creased (p<0.01); the regional and global left ventricular function we re impaired significantly with p<0.01 for all the measured variables; and the myocardial ultrastructural changes were characterized by a sev ere trapping of red cells in capillary and other moderate ischemic inj uries. Pretreatment with aspirin could markedly attenuate the extent o f the above changes while alpha-adrenergic blockade with phentolamine did not alter these changes. In sharp contrast to the intracoronary in fusion route, gblood infused through intravenous route showed no effec ts on CVR and cardiac function. All the changes initiated by intracoro nary perfusion of gblood were similar in nature to those induced by is chemia. Thus, red cells with reduced deformability perfused into coron ary artery, but not femoral vein, caused a significant decrease in CF and the resultant impairment of cardiac function. The reduction in CF was not due merely to plugging up the circulation by abnormal red cell s, but may also be mediated through platelet aggregation or release of some vasoconstrictor substances from platelets.