Comparison of the thromboxane synthetase inhibitor dazoxiben and the prostacyclin mimetic iloprost in an animal model of acute ischaemia and reperfusion.

The thromboxane (TX) synthetase inhibitor dazoxiben (80 micrograms/kg X min) and the prostacyclin analogue iloprost (0.6 micrograms/kg X min) were investigated in a cat model of acute myocardial ischaemia (MI) plus reperfusion. The agents were i.v. infused starting 30 min after LAD occlusion until the end of the observation period (5h). Dazoxiben significantly reduced the MI-induced increase in TXB2 and platelet ATP secretion. Dazoxiben did not influence the MI-induced depression in platelet count (PC), the fall in CK-specific activity or the ECG alterations associated with reperfusion whereas iloprost resulted in a nearly complete recovery of these parameters. These data suggest an efficacy of PGI2 administration but not of TX synthetase inhibition in preserving the myocardium from reperfusion injury. These data indicate that reperfusion-induced tissue damage appears not to be a thromboxane-dependent phenomenon.