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(Silvain, 2011). In this study we included the total
volume of retrieved fragments in both SEM and
histological analysis. Differently, the compositional
results of SEM analysis from Silvain et al. were
limited to the main aspirated piece of the thrombus.
This could partly explain differences in composition
and time course between the two datasets, but the
SEM exclusion criterion we applied could also have
introduced a bias in sample selection.
Difficulties in evidencing significant differences
in thrombus composition among the sample groups
with different ischemic times could also be related to
the inadequacy of the ischemic time in properly
defining the thrombus age. Previous
histopathological studies conducted on larger cohort
of STEMI patients evidenced that intracoronary
aspirated material by thrombectomy is frequently
heterogeneous in terms of thrombus age (Rittersma,
2005, Kramer 2009). In 51% of cases, older thrombi
(>1 day) were reported, which suggests an important
discrepancy between the time of onset of the
thrombotic process and the occurrence of acute
clinical symptoms (<12 h in patients treated with
TA) (Rittersma, 2005). The authors concluded that
plaque instability frequently occurs days or even
weeks before occlusive coronary thrombosis
(Kramer, 2009).
The time between plaque rupture and thrombus
formation is still unpredictable. Sudden coronary
occlusion is often preceded by a variable period of
plaque instability and thrombus formation, initiated
days or weeks before onset of symptoms. The
aspirated thrombus may be older than expected from
the duration of the ischemic time (Kramer, 2009),
and younger thrombus could be superimposed onto
an older thrombus, thereby potentially confusing the
observations.
5 CONCLUSIONS
A multiscale analytical approach to characterize
samples obtained by catheter aspiration in STEMI
patients has been realized by integrating qualitative
information coming from the visual assessment of
the coronary thrombus with compositional
quantitative data obtained from histological and
SEM analysis. Method here presented deserves high
potential for understanding the mechanisms of
thrombus formation in STEMI and for investigating
correlations between composition and thrombus age.
Significant differences in composition were
found, showing a higher amount of platelets and
fibrin respectively for “white” and “red” thrombi.
No significant correlations were found between
composition and ischemic time, supporting
previously reported data showing that plaque
instability and thrombus formation can occur within
longer time interval before AMI symptom onset.
Possible associations between thrombus
composition determined with a multiscale approach
and thrombus age assessed by histopathological
methods should be investigated in future studies.
Eventually, specific analysis could be performed
to elucidate potential association between thrombus
composition and antithrombotic drug treatment.
ACKNOWLEDGEMENTS
Authors are grateful to the staff of the Cardiology
Division of the Trento Hospital for sample
collection.
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AssessingCompositionofCoronaryThrombusinSTEMIPatients-AMultiscaleApproachtoCharaterizeSamples
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