Prevention by a stable prostacyclin analogue, 7-oxoprostaglandin I2 of the platelet loss during experimental cardiopulmonary bypass.

A great percentage of circulating platelets is lost through activation and aggregation during total body perfusion used in cardiac surgery. The effect on platelet count of a chemically stable prostacyclin analogue, 7-oxoprostaglandin I2 was investigated in anaesthetized dogs subjected to cardiopulmonary bypass of 120 min duration. In control (untreated) dogs the perfusion decreased the amount of circulating platelets by more than 60% of their initial value. This loss was completely prevented by i.v. infusion of the analogue (50 micrograms.kg-1.min-1) without affecting the haemodynamic state of the preparation. With the infusion of native prostacyclin at the same rate, a similar protective action was found to be associated with significant arterial hypotension. It was concluded that 7-oxoprostaglandin I2 is an useful pharmacological tool for maintaining physiological platelet counts and thus preserving haemostatic stability in open heart surgery.