Coronary angioscopic findings in the infarct-related vessel within 1 month of acute myocardial infarction: natural history and the effect of thrombolysis.
BACKGROUND
Limited angioscopic information is available on the natural history of infarct-related plaque after myocardial infarction (MI), in particular the effect of thrombolysis.


RESULTS
We studied with angioscopy the morphological characteristics of the infarct-related lesion in 56 patients between 24 hours and 4 weeks after MI. Forty of these patients were initially treated with a thrombolytic agent. Most lesions were complex (complex + ulcerated shape = 54%). The predominant color of the plaque was yellow in 79% of cases; only 6% were uniformly white. Angioscopically visible thrombus was found in 77% of cases. Despite angioscopic evidence of instability, only 7% of the patients had post-MI angina. During the 1-month time window since the occurrence of MI, there was no significant difference in the angioscopic appearance of the plaque except for a slight increase in uniformly white plaques (P=.07). The use of a thrombolytic agent at the onset of MI was associated with a reduction in thrombus size and less protruding thrombi (P=.02) but not with a decreased frequency of plaque containing thrombi. Furthermore, a trend for more frequently ulcerated plaques (45% versus 16%, P=.06) was associated with the use of a thrombolytic agent.


CONCLUSIONS
These results suggest that healing of the infarct-related lesion requires more than 1 month and that an "unstable" yellow plaque with adherent thrombus is common during that period. This finding may partly explain the unique behavior of recent infarct-related lesions, which are more prone to occlude than other lesions.
Van Belle
E
E
Service de Cardiologie B et Hémodynamique, Hôpital Cardiologique, Lille, France.
Lablanche
J M
JM
Bauters
C
C
Renaud
N
N
McFadden
E P
EP
Bertrand
M E
ME
D017546:Angioscopy; D017023:Coronary Angiography; D003328:Coronary Thrombosis / Q000188:drug therapy / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000473:pathology*; D015912:Thrombolytic Therapy; D013997:Time Factors