Objectives: We sought to test the hypothesis that virtual histology
characteristics of the culprit lesion in patients with ST-elevation
myocardial infarction are associated with blood flow restoration after
thrombolysis.
Methods: Consecutive patients referred for coronary angiography after
successful thrombolysis were included in this correlational
cross-sectional study. Evaluation with intravascular ultrasound (IVUS)
and virtual histology of the culprit arterial segment was performed in
all cases.
Results: Forty-eight patients (60.5 +/- 10.7 years) were included. TIMI
flow grade 3 was found in 24 (50%). Diabetes was strongly associated
with lower TIMI flow 3 rate (26.7% vs 60.6%; p = 0.029) and there was
a significant difference in the time to thrombolysis (2.0 +/- 0.8 hours
in those with TIMI flow 3 vs 3.0 +/- 0.7 hours in TIMI flow grades 1-2;
p < 0.001). Patients with TIMI flow grades 3 and 1-2 had similar
absolute total plaque volume (152.8 +/- 59.3 mm(3) vs 147.5 +/- 92.3
mm(3); p = 0.817) and absolute necrotic core (NC) volume (31.2 +/- 13.9
mm(3) vs 33.6 +/- 23.2 mm(3); p = 0.671). However, there were
significant differences in the relative NC content, both in proportion
to the whole plaque volume (26.3% vs 29.9%; p = 0.016) and as an area
fraction at the largest NC site (31.5% vs 40.3%; p < 0.001).
Conclusion: The NC content of atherosclerotic plaques is meaningful for
flow restoration after the occurrence of a coronary event. This finding
highlights the importance of plaque composition, as studied with virtual
histology, not only for the sequence of processes leading to an acute
plaque-related event, but also for thrombus formation and lysis,
following the occurrence of such an event. (C) 2014 Elsevier Ireland
Ltd. All rights reserved
