Seventeen dogs (22.1 percent) exhibited one or more findings indicative of intracoronary thrombosis (Fig 1). Frequency of arteriographic findings was as follows: minor lumen irregularities, 0 (0.0 percent); discrete filling defects, 12 (15.6 percent); staining of thrombus, 5 (6.5 percent); slowed or interrupted flow, 12 (15.6 percent). Slowed or interrupted flow always coexisted with either a discrete filling defect or contrast retention. Total interruption of flow was present in three dogs 2 h after angioplasty. For purposes of analysis, the presence of at least one of the above signs was considered indicative of thrombosis at arteriography; this state was designated AT -I-, as opposed to AT—, which denoted absence of all arteriographic signs of thrombosis. Analysis of the evolution of all arteriograms showed no differences from the results of the 120-min arteriogram (before death); however, this analysis allowed better interpretation of this injection.
The overall incidence of mural thrombosis at histologic analysis was 65.0 percent (50 of 77 dogs). All such thrombi exhibited the typical histologic structure of a thrombus, as opposed to a postmortem clot. Most adhered to the wall at the exact site of intimal disruption. Most important, the histologic structure was similar between AT + and AT— thrombi. No clots were observed in the circumflex artery or in nondilated portions and branches of the LAD. In four dogs sham-manipulated with the deflated catheter, no clots were found at histology. Taken together, those data strongly suggest that the observed thrombi were formed before death.
The Role of Coronary Arteriography in Demonstration of Mural Thrombosis after Angioplasty (6)