Adverse in-hospital ischemic complications are increased following PTCA in unstable angina in comparison to stable angina and may relate to the high incidence of intracoronarythrombus associated with unstable angina. We have previously noted that following PTCA, delayed views (15min. postPTCA) often demonstrate lesional irregularities and filling defects suggestive of thrombus not noted immediately (1 min.) following PTCA. In the TAUSA trial, unstable angina patients were randomized to Urokinase or placebo during PTCA of the culprit lesion. One and 15 minute post PTCA angiograms were routinely assessed for major dissection (MDl or thrombus (T) formation. Because ischemic events were increased with urokinase, only placebo patients were evaluated in this analysis. MD was defined as a spiral D or a D causing >50% diameter reduction.No T or MD at 15 min (N=170)T or MO at 15 min (N=50)No T or MD at 1 min (N=202)Acute closure (%)0* , ‡8*2‡Emergent bypass (%)0†4†0.5Any ischemic in hospital event (%)3.5‡10‡4*p<0.005†p=0.05‡p<010The presence of T or MD at 15 min. post PTCA was associated with a higher incidence of acute closure and other adverse clinical events vs. no T or MD at 15 min. post PTCA. There was a trend to a lower incidence of acute closure when the 15 min. angiogram revealed no T or MD in comparison to no T or MD at 1 min. post PTCA. Thus, T or MD on delayed views identify a group of patients who are at a higher risk of adverse events. The absence of Tor MD at 15 min. following PTCA in unstable angina is associated with few adverse events. These data suggest that delayed views should be routinely performed following PTCA in unstable angina.