Mechanism of restenosis after PTCA suggests that platelets play an important role in this response. Since a stable PGI2 analogue, U-61, 431F (group U), has strong platelet inhibitory action, we investigated the preventing effect of U-61, 431F on restenosis and other complications in patients undergoing PTCA. The effect was compared with control (group C). There was no difference in patients background in the two groups. No abrupt coronary occlusion or other cardiac events were observed in group U, but there was two events in group C. Though there was no significant difference in the results between the 2 groups, group U showed lower patient restenosis rate (group U: group C 33.3%:57.1%) and lesion restenosis rate (group U: group C 25.0%:37.5%) based on follow-up angiography. No serious adverse effect was observed in the group U. Thus U-61, 431F may be effective in preventing acute cardiac events during PTCA and restenosis after PTCA.
