Assessing Composition of Coronary Thrombus in STEMI Patients
A Multiscale Approach to Charaterize Samples Obtained by Catheter Aspiration
Francesco Tessarolo
1,2
, Emiliana Bonomi
2
, Federico Piccoli
3
, Fabiola Morat
4
, Marta Rigoni
1
,
Iole Caola
3
, Mattia Barbareschi
5
, Patrizio Caciagli
3
, Simone Muraglia
4
, Roberto Bonmassari
4
and Giandomenico Nollo
1,2
1
IRCS project, Bruno Kessler Foundation, via Sommarive 18, Trento, Italy
2
Department of industrial Engineering, University of Trento, via Mesiano 77, Trento, Italy
3
Department of Laboratory Medicine, Azienda Provinciale per i Servizi Sanitari di Trento, via Degasperi 79, Trento, Italy
4
Division of Cardiology, Santa Chiara Hospital, l.go Medaglie d’oro 9, Trento, Italy
5
Division of Pathology, Santa Chiara Hospital, l.go Medaglie d’oro 9, Trento, Italy
Keywords: Thromboaspiration, ST-Segment Elevation Myocardial Infarction, Scanning Electron Microscopy,
Histology.
Abstract: Percutaneous catheter thrombectomy allows collecting coronary thrombi from patients with ST-segment
elevation myocardial infarction, preserving most of the sample characteristics available for both visual
assessment and compositional analysis. This study aimed at identifying the association between thrombus
macroscopic aspect and composition and, secondly, correlations between composition and ischemic time.
Aspirated thrombi were grouped into “white”, “red” or “mixed” according to their macroscopic appearance.
Platelets, RBCs and fibrin were quantified on thrombus surface by SEM and on thrombus sections by a
modified Carstairs histochemical staining. Fifty-three samples from 51 patients were included. The median
[inter-quartile range] ischemic time was 210 [190-265] min. Seven (13%) “white”, 19(36%) “mixed” and
27(51%) “red” thrombi were macroscopically identified. Median thrombus composition assessed by SEM
was 23[11-41]%, 43[26-62]%, and 24[11-37]% for platelets, RBCs and fibrin respectively. Median
histological analysis was 10[5-26]%, 45[31-64]% and 30[18-49]% for the same components. Significant
difference in composition were found between “white” and “red” thrombi, showing respectively a higher
amount of platelets (p=0.003) and fibrin (p=0.007). No significant correlations were found between
composition and ischemic time suggesting that plaque instability and thrombus formation can occur before
the symptom onset.
1 INTRODUCTION
Thrombus aspiration (TA) is a recommended
technique in the treatment of myocardial infarction
(MI) allowing thrombus removal from the culprit
artery via a specific catheter (Keeley, 2003; Van der
Werf, 2008, Steg, 2012). A reduced mortality in
patients affected by myocardial infarction with ST-
segment elevation (STEMI) has been associated to
the use of TA in conjunction with primary
percutaneous intervention (PCI) (De Luca, 2008;
Vlaar, 2008; Burzotta, 2009).
TA allows collecting the biological aspirate in a
minimally invasive way, preserving most of the
original thrombus characteristics that are available
for direct visual assessment and complementary
laboratory analysis. The retrieved thrombus can
varies in size, shapes and colour, giving readily
available information to the interventional
cardiologist (Quadros, 2012). Histological methods
are also available for the characterization of
thrombus morphology and for assessing thrombus
age (Kramer, 2008) and scanning electron
microscopy (SEM) has been proposed as a valid
method for assessing composition of aspirated
material (Silvain, 2011). These methods have the
potentials of tracing the evolution of the pathology
from the plaque rupture to the vessel recanalization.
However, histopathological and microstructural
analyses are time consuming and the macroscopic
5
Tessarolo F., Bonomi E., Piccoli F., Morat F., Rigoni M., Caola I., Barbareschi M., Caciagli P., Muraglia S., Bonmassari R. and Nollo G..
Assessing Composition of Coronary Thrombus in STEMI Patients - A Multiscale Approach to Charaterize Samples Obtained by Catheter Aspiration.
DOI: 10.5220/0005144600050012
In Proceedings of the 2nd International Congress on Cardiovascular Technologies (CARDIOTECHNIX-2014), pages 5-12
ISBN: 978-989-758-055-0
Copyright
c
2014 SCITEPRESS (Science and Technology Publications, Lda.)
aspect of the thrombus remains the most accessible
information to use at the bedside (Quadros, 2012).
We aimed at developing and applying a
multiscale approach by integrating the macroscopic
evaluation of the aspirated material with
compositional data obtained from both histological
and SEM analysis on a series of coronary thrombi
collected during PCI with TA on STEMI patients.
Data will be analyzed in order to identify firstly the
association between macroscopic aspect of the
thrombus and its composition and, secondly,
possible associations between thrombus aspect and
composition with ischemic time.
2 METHODS
Coronary thrombi were prospectively collected
between November 2012 and November 2013 from
all the STEMI patients admitted at the Division of
Cardiology of the Santa Chiara Hospital in Trento,
Italy, within 12 hours from the beginning of the MI
symptoms and treated with catheter thrombus
aspiration (Export 6F, Medtronic, Santa Rosa,
California) before PCI. Procedures were performed
according to the ESC guidelines (Steg, 2012).
Aspirated thrombi were collected on the
disposable filter, washed with sterile saline to
remove excess of blood and immediately fixed in
2.5% glutaraldehyde in 0.1M phosphate-buffered
solution. Specimens were then stored in the fixative
solution at 4°C until they were analyzed.
Demographics, risk factors, blood biomarkers on
admission, ischemic time (defined as the time lag
between the onset of the AMI symptoms and the
reperfusion therapy), and antithrombotic treatment
were recorded on a data collection form.
2.1 Macroscopic Evaluation
In order to make the macroscopic evaluation of the
aspirated material standardized and blinded to
patients’ characteristics and clinical conditions,
thrombi were not evaluated immediately after
aspiration. After a minimum fixation time of 48h, a
photographic documentation of the aspirated
material was performed by collecting one image per
sample at 10x magnification with a stereo-
microscope equipped with a colour digital camera
under constant illumination conditions. Collected
images were pooled and independently evaluated by
two senior interventional cardiologists blinded to
patient details and clinical characteristics. Aspirated
thrombi were grouped into “white”, “red” or
“mixed” according to their macroscopic appearance
and colour (Figure 1).
Figure 1: Macroscopic classification of aspirated coronary
thrombi. Representative image of a “white” (a), “mixed”
(b), and “red” (c) sample. Bar is 5 mm.
2.2 Scanning Electron Microscopy and
Compositional Analysis
Before SEM analysis, samples were washed once in
0.1 M phosphate buffer and trice in distilled water,
de-hydrated in ascending hydro-alcoholic solutions,
dried in a laminar flow cabinet, mounted on a
sample holder with double-sided conductive carbon
tape, and sputter-coated with gold. SEM analysis
was conducted on the thrombus surface with a
XL30, ESEM FEG scanning electron microscope
(FEI, Philips, Nederland).
To perform an operator-independent choice of
the SEM fields of view, 20 point of interest were
previously determined by superimposing a squared
grid to the stereomicroscopic colour picture. A set of
20 electron-micrographs per each sample was than
obtained in the same point of interest at a
magnification of 2000x. The composition of the
thrombus was determined by performing a semi-
quantitative analysis of the SEM images, modifying
the procedure previously proposed by Lucas et al.
(Lucas, 2013). Briefly, a squared grid of 10μm
element size was superimposed to each SEM image
to obtain a total of 400 point of interest per sample.
The observation of each point of interest allowed to
quantify the following micro-morphological
features: a) “platelets” (2 μm wide globules
occurring as aggregates or adherent to the fibrin
strands), b) “erythrocytes” (RBCs) (biconcave disc-
shaped cells of about 7 μm in diameter), c) “fibrin”
(fibrin network or fibrin fibres), d) “other” (other
morphologies not included in the previous features).
Representative SEM micrographs of the different
micro-morphological features are reported in Figure
2.
SEM features quantification was considered
feasible if “other” occurred in less than 50% of the
investigated points. After the exclusion of points
CARDIOTECHNIX2014-InternationalCongressonCardiovascularTechnologies
6
associated to “other”, the percentage of occurrence
for each feature of interest was finally computed for
each thrombus.
Figure 2: SEM images of the aspirated thrombus.
Representative fields of view with a prevalence of
platelets (a), RBCs (b), fibrin (c), and other features (d).
Bar is 10 microns.
2.3 Histochemical Staining and Feature
Quantification
After SEM characterization, thrombi were released
from the carbon tape by adding a drop of absolute
ethanol on the stub surface, carefully transferred on
histological cassettes and re-hydrated by immersion
in 70% ethanol in water for 24h and in distilled
water for 48h. After this post-SEM conditioning,
samples were processed for permanent histology by
immersion in ascending hydro-alcoholic solutions,
100% ethanol and 100% xylene. After paraffin
impregnation and embedding, 3 µm thick sections
were cut with a rotary microtome.
Two consecutive sections per sample were
stained respectively with haematoxylin-eosin stain
(H&E) and a modified Carstairs stain (Figure 3). We
adapted the original Carstairs staining method
(Carstairs, 1965) to identify RBCs, platelets and
fibrin in the thrombus sections. Staining times and
fixation solutions were optimized for a better
differentiation of thrombus components as described
elsewhere (Lucas, 2014). Briefly, paraffin sections
were hydrated, placed in 5% ferric alum for 10
minutes, rinsed in running tap water, stained in
Mayer’s haematoxylin for 5 minutes, and then rinsed
again in running tap water. Sections were placed for
4 minutes in picric acid-orange G solution (20 mL
saturated aqueous picric acid, 80 mL saturated picric
acid in ethanol, and 0.2 g orange G) and then rinsed
in distilled water. Sections were then placed in
ponceau-fuchsine solution (0.5 g acid fuchsine, 0.5 g
ponceau 2R, 1 mL acetic acid, and distilled water to
100 mL) for 2 minutes and then rinsed in distilled
water. Sections were treated with 1%
phosphomolybdic acid for 3 minutes, rinsed in
distilled water, stained with aniline blue solution (1
g aniline blue in 100 mL 1% acetic acid) for 45
minutes, decoloured in 1% aqueous acetic acid for 3
minutes, rinsed in several changes of distilled water,
dehydrated, cleared, and mounted with acrylic
medium. On sections obtained from thrombi fixed
for 48 hours or longer, Carstairs method produces
differential staining of fibrin (bright red), platelets
(grey-blue to navy), and RBCs (yellow) (Carstairs,
1965).
Platelet, RBCs and fibrin were quantified on
Carstairs stained sections by setting specific colour
thresholds in the L, a*, b* colour space (Figure 4).
Pixel number for each feature was computed and
percent occurrence over the whole section area was
considered for the statistical analysis.
Figure 3: Histological features of a mixed thrombus.
Consecutive sections stained with haematoxylin-eosin (a)
and modified Carstairs stain (b). Bar is 1 mm.
Figure 4: Histological analysis on a mixed thrombus
section stained with Carstairs method (left).
Representative colours associated to the three components
of interest are shown. Binary images after specific
threshold for platelets (a), RBCs (b) and fibrin (c). Inset d)
reports about components not recognized in the three
previous features and excluded from the calculation of
compositional percentages. Bar is 1 mm.
AssessingCompositionofCoronaryThrombusinSTEMIPatients-AMultiscaleApproachtoCharaterizeSamples
ObtainedbyCatheterAspiration
7
Table 1: Patients characteristics.
Demographics
Age, years 63.0 ±13.1
Male 41 (84.3%)
Risk factors
Hypertension 58%
Active smoker 61%
Dyslipidemia 26%
Diabetes mellitus 13%
Familiarity 41%
Time delays
Symptom onset to ASA, min 95 [50-140]
Symptom onset to ADP inhibitor,
min
120 [90-180]
Symptom onset to PCI, min 210 [190-265]
Biomarkers on admission
Troponin I, µg/ml 0.325±1.293
Platelet, mm
-3
252±82
CRP, mg/l 7.9±14.8
PT, INR 1.02±0.10
Creatinine clearance, ml/min 88.9±39.3
Antithrombotic treatment
ASA 52 (98.1%)
ADP receptor inhibitor 53 (100%)
Clopidogrel 21 (39.6%)
Prasugrel 32 (60.4%)
GP IIb/IIIa inhibitor 25 (47.2%)
Pre-admission 0 (0%)
Catheterization laboratory 25 (47.2%)
Infarct related artery
LAD 32 (60.4%)
RCA 17 (32.1%)
Cx 4 (7.5%)
CABG 0 (0.0%)
Values are mean ± SD, n (%), or median [interquartile range].
ASA : acetylsalicylic acid; ADP: Adenosine diphosphate; CABG:
coronary artery bypass grafting; CRP: C-reactive protein; Cx:
circumflex coronary artery; GP: glycoprotein; LAD: left anterior
descending coronary artery; RCA: right coronary artery.
2.4 Statistical Analysis
Categorical variables were expressed as percentages.
The results for normally distributed continuous
variables are expressed as mean±standard deviation,
and continuous variables that did not have a normal
distribution are presented as median and inter-
quartile interval (IQR).
The intra and inter observer correlations in the
macroscopic analysis were assessed by weighted
kappa coefficients considering that macroscopic
categories were ordered from “white” to “mixed”
and “red”. Kappa coefficient was interpreted as
reported by Altman et al. (Altman, 1991).
The non-parametric Kruskal–Wallis test was used to
compare three groups. If a significant difference was
found with the Kruskal–Wallis test, then a Mann–
Whitney U test was used to compare each pair of
groups. Wilcoxon non-parametric test was used to
compare distributions with paired data obtained
from SEM and histological analysis. Categorical
variables were compared using Fisher exact test.
Spearman correlation coefficients were calculated to
assess the relationships between platelets, RBCs and
fibrin contents vs. ischemic time.
Multivariate linear regression analysis was
performed to identify independent factors associated
with the thrombus composition (age, sex and infarct
related artery, antithrombotic treatment). All
analyses used two-sided tests with a significance
level of p<0.05. Data were analysed using STATA
version 13.0 for Windows (STATACorp. College
Station, TX, USA).
3 RESULTS
Sixty-three thrombi were obtained from 61 patients.
Among them, six cases were excluded for
incomplete clinical records and one sample failed
histological preparation. Fifty-six aspirated thrombi
were subjected to compositional analysis.
SEM characterization was not feasible according
to the adopted criterion (“other” > 50%”) in 3
samples, leaving 53 samples from 51 patients who
were eventually considered for reporting and
statistical analysis. Patients’ characteristics are
summarized in Table 1.
3.1 Thrombus Composition
Macroscopic classification gave 7(13%) “white”,
19(36%) “mixed” and 27(51%) “red” thrombi.
Intra-observer agreement was “good” (K= 0.785)
with 84.9% of agreements. Inter-observer agreement
was “moderate” (K=0.437) with 60.4% of
agreements. “Red” and “white” thrombi were
generally categorized in the same way by the raters,
but discrepancies were frequent in evaluating mixed
thrombi.
Features quantification on SEM images showed a
median [IQR] composition of 23[11-41]%, 43[26-
62]%, and 24[11-37]% for platelets, RBCs and fibrin
respectively. At the histological analysis, the same
samples showed a median [IQR] composition of
10[5-26]%, 45[31-64]% and 30[18-49]% for
platelet, RBCs and fibrin respectively. Data obtained
from SEM and histological methods were consistent
and a paired non-parametric analysis showed no
significant differences between the compositional
distributions determined by the two methods.
CARDIOTECHNIX2014-InternationalCongressonCardiovascularTechnologies
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To elicit possible associations between
compositional data and macroscopic thrombus
characteristics, results from SEM and histology were
sub-grouped according to the macroscopic
classification. Results are summarized in Figure 5.
Sub-group analysis of SEM compositional data
showed a higher amount of platelets (p=0.003) and a
lower amount of fibrin (p=0.007) in “white” thrombi
in respect to “red” thrombi. No significant difference
Figure 5: Composition of aspirated thrombi sub-grouped
according to macroscopic categories. Values are indicated
as percent of platelets, RBCs and fibrin determined by
SEM (a) or histological (b) analysis.
Figure 6: Number of aspirated thrombi (sub-grouped by
macroscopic characteristic) plotted according to ischemic
time.
was found for the amount of RBCs within different
macroscopic sub-groups, although a trend to higher
median values of RBCs was found from “white” to
“red” thrombi. Intermediate features were found for
“mixed” thrombi but no significant compositional
difference was present between “mixed” and “red”
or “white” and “mixed” thrombi.
Differently from SEM compositional data,
histological composition showed no significant
compositional difference among the three
macroscopic sub-groups.
3.2 Thrombus Composition Vs.
Ischemic Time
Ischemic time for the 53 samples collected in this
study ranged from 110 to 720 min with a median
value of 210 min. According to previously proposed
criteria (Silvain, 2011), ischemic time was
categorized into three intervals (≤3 h, 3 to 6 h, ≥6 h).
The number of “white”, “mixed” and “red” thrombi
grouped according to the ischemic time intervals is
reported in Figure 6. No statistically significant
difference was observed, but a large variability in
ischemic time was associated to “red” thrombi.
Figure 7: Composition of aspirated thrombi (percent of
platelets, RBCs and fibrin) according to the three ischemic
time intervals. Compositional data were obtained from
SEM (a) and histological (b) methods.
AssessingCompositionofCoronaryThrombusinSTEMIPatients-AMultiscaleApproachtoCharaterizeSamples
ObtainedbyCatheterAspiration
9
Differently, all “white” thrombi were collected from
patients with an ischemic time from 3 to 6 h.
The amount of platelets, RBCs and fibrin
according to the three ischemic time intervals is
reported in Figure 7 for compositional data obtained
from SEM and histological methods. No significant
difference in composition among the three sub-
groups was found both on data obtained from SEM
and from histology.
A univariate linear regression was performed on
platelets, RBCs, and fibrin amount according to
ischemic time, showing no linear association
between composition and ischemic time.
A multivariate linear regression model was also
performed to include in the analysis the potential
confounding variables (age, sex, infarct related
artery, risk factors, blood biomarkers, antithrombotic
therapy) showing no significant effects on the
thrombus composition.
4 DISCUSSION
The investigation of coronary thrombus
characteristics and composition deserves high
interest for defining the pathogenetic mechanism of
acute coronary syndromes, for optimizing the
therapeutic treatment according to thrombus
characteristics and for having additional prognostic
data on patients’ mortality. Thrombi obtained by an
aspiration device during the PCI treatment can give
a rapid and informative feedback to the operator by
the direct visual observation of the collected
material. Moreover, the same biological aspirate is a
good candidate for additional analysis on
microstructure and composition. This work presents
a new histological method using trichromic
histochemical staining and colour image analysis for
quantifying platelets, RBCs and fibrin on thrombus
sections. The amount of the same features on the
thrombus surface was also determined, in an
independent way, by SEM and semi-automatic
image analysis. Macroscopic features of the
aspirated samples were also determined blindly to
patients’ clinical details by acquiring a low
magnification picture under controlled illumination
conditions. This approach represents a first example
of integrated multiscale analysis that was not
reported before in literature according to authors’
knowledge. Results were obtained from 53 thrombus
samples in a fully paired fashion, starting from a
macroscopic qualitative classification to a
quantitative determination of fibrin, platelets and
RBCs by both histochemical and SEM methods.
Different macroscopic classifications were
previously proposed to classify the colour of
aspirated thrombi. Quadros et al. proposed a
dichotomous classification into “white” and “red”
thrombi (Quadros, 2012). They found that “white”
thrombi occurred in one third of STEMI cases and
were associated with lower ischemic time when
compared with “red” thrombi (Quadros, 2012).
Uchida et al. proposed a larger number of classes for
the angioscopic in-situ classification, including also
“transparent”,” frosty glass–like”, “light red”,
“mixed”, and “brown” thrombi (Uchida, 2011). In
accordance with other authors (Kirchof, 2003) and
considering the inhomogeneities of colour within
many aspirated samples, we considered three
macroscopic categories, grouping thrombi into
“white”, “mixed” and “red”. However, this
classification showed a lower inter-observer
agreement than those reported by Uchida and co-
workers (Uchida, 2011). Differently from other
studies where the macroscopic classification was
performed during the PCI procedure, in this study
the assignment of the macroscopic category was
realized in a completely blinded fashion by
evaluating only the low magnification image of the
aspirated material captured with a digital camera.
The difference in the agreement rate could be in part
related with this methodology.
The compositional analysis was performed by a
non-destructive SEM analysis of the outer surface of
the thrombus. We adapted a previously presented
protocol for SEM preparation (Silvain, 2011) in
order to limit sample damage and allowing the
subsequent histological analysis on the same
aspirated material. Median compositional results
obtained here were partly in agreement with those
previously observed (Silvain, 2011). Specifically,
we obtained a lower amount and fibrin and a higher
amount of RBCs than those previously reported.
Values for the amount of platelets are super
imposable with those reported by Silvain et al.
Surprisingly, although RBCs in clots are the
origin of the word “red” (usually referred as “old”)
thrombi as opposed to platelet-rich “white” (usually
referred as “young”) thrombi, we did not find
significant differences in RBCs among different
macroscopic sub-groups. Similarly, Silvain and co-
workers failed to note a significant correlation
between RBCs content and ischemic time by the
SEM compositional analysis (Silvain, 2011).
Although the present study included a higher
number of samples we did not evidence the same
significant association previously reported between
fibrin and platelets amount vs. ischemic time
CARDIOTECHNIX2014-InternationalCongressonCardiovascularTechnologies
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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.
REFERENCES
Altman, DG., 1991. Practical statistics for medical
research. Chapman & Hall/CRC.
Burzotta, F., De Vita, M., Gu, YL., et al., 2009. Clinical
impact of thrombectomy in acute ST-elevation
myocardial infarction: an individual patient-data
pooled analysis of 11 trials. Eur. Heart. J. 30
(18):2193-2203.
Carstairs, KC., 1965. The identification of platelet
antigens in histological sections. J. Path. bact. 90 (1):
225-31.
De Luca, G., Dudek, D., Sardella, G., et al., 2008.
Adjunctive manual thrombectomy improves
myocardial perfusion and mortality in patients
undergoing primary percutaneous coronary
intervention for ST-elevation myocardial infarction: a
meta-analysis of randomized trials. Eur. Heart. J.
29(24):3002-3010.
Keeley, EC., Boura, JA., Grines, CL. 2003. Primary
angioplasty versus intravenous thrombolytic therapy
for acute myocardial infarction: a quantitative review
of 23 randomized trials. Lancet 361: 13-20.
Kirchhof, K., Welzel, T., Mecke, c., et al., 2003.
Differentiation of white, mixed and red thrombi: value
of CT in estimation of the prognosis of thrombolysis-
phantom study. Radiology 228:126-130.
Kramer, MC., Allard, C., Van der Wal, AC., et al., 2008.
Presence of older thrombus is an independent
predictor of long term mortality in patients with ST-
elevation myocardial infarction treated with thrombus
aspiration during primary percutaneous coronary
intervention. Circulation 118:1810-1816.
Kramer, MC., Van der Wal, AC., Koch, KT., et al., 2009.
Histopatological features of aspirated thrombi after
percutaneous coronary intervention in patients with
AssessingCompositionofCoronaryThrombusinSTEMIPatients-AMultiscaleApproachtoCharaterizeSamples
ObtainedbyCatheterAspiration
11
ST-elevation myocardial infarction. PLoS One 4:e
5817.
Lucas, TC., Tessarolo, F., Veniero, P., et al., 2013.
Hemodialysis catheter thrombi: visualization and
quantification of microstructures and cellular
composition. J. Vasc. Access 14(3):257-263.
Lucas, TC., Tessarolo, F., Veniero, P., et al., 2014.
Quantification of fibrin in blood thrombi formed in
hemodialysis central venous catheters: a pilot study on
43 CVCs. J. Vasc. Access Jan 21 Epub ahead of print
doi: 10.5301/jva.5000200.
Quadros, SA., Cambruzzi, E., Sebben J., et al. 2012. Red
versus white thrombi in patients with ST-elevation
myocardial infarction undergoing primary
percutaneous coronary intervention: clinical and
angiographic outcomes. Am. Heart J. 164:553-560.
Rittersma, SZ., Van der Wal, AC., Koch, KT., et al., 2005.
Plaque instability frequently occurs days or weeks
before occlusive coronary thrombosis: a pathological
thrombectomy study in primary percutaneous coronary
intervention. Circulation 111 (9):1160-1165.
Silvain, J., Collet, JP., Nagaswami, C, et al., 2011.
Composition of coronary thrombus in acute
myocardial infarction. J. Am. Coll. Cardiol. 57
(12):1359-1367.
Steg, PG., James, SK., Atar, D., et al, 2012. ESC
Guidelines for the management of acute myocardial
infarction in patients presenting with ST-segment
elevation. Eur. Heart. J. 33(20):2569-2619.
Uchida, Y., Uchida, Y., Sakurai, T., et al., 2011.
Syndrome Using Dye-Staining Angioscopy
Characterization of Coronary Fibrin Thrombus in
Patients With Acute Coronary. Arterioscler. Thromb.
Vasc. Biol. 31:1452-1460.
Van de Werf, F., Bax, J., Betriu, A., et al., 2008. ESC
Committee for practice guidelines. Management of
acute myocardial infarction in patients presenting
with persistent ST-segment elevation: the task force on
the management of ST-segment elevation. Eur. Heart
J. 29: 2909-2945.
Vlaar, PJ., Svilaas, T., van der Horst, IC., et al., 2008.
Cardiac death and reinfarction after 1 year in the
Thrombus Aspiration during Percutaneous coronary
intervention in Acute myocardial infarction Study
(TAPAS): a 1-year follow-up study. Lancet
371(9628):1915-20.
CARDIOTECHNIX2014-InternationalCongressonCardiovascularTechnologies
12
