Time Dependent Changes in Atherosclerotic Plaque Composition in ...
Transcript of Time Dependent Changes in Atherosclerotic Plaque Composition in ...
DOI: 10.1161/CIRCULATIONAHA.113.007603
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Time Dependent Changes in Atherosclerotic Plaque Composition in Patients
Undergoing Carotid Surgery
Running title: van Lammeren et al.; Carotid plaque stabilisation
Guus W. van Lammeren, MD, PhD1,2*; Hester M. den Ruijter, PhD1,3*;
Joyce E. P. Vrijenhoek, MD1,2,4; Sander van der Laan, MSc1; Evelyn Velema, MSc1;
Jean-Paul P. M. de Vries, MD, PhD4; Dominique P.V. de Kleijn, PhD1,4,5; Aryan Vink, MD, PhD6;
Gert Jan de Borst, MD, PhD2; Frans L. Moll, MD, PhD2; Michiel L. Bots, MD, PhD3;
Gerard Pasterkamp, MD, PhD1
1Experimental Cardiology Laboratory, University Medical Center Utrecht; 2Dept of Vascular Surgery, University Medical Center Utrecht; 3Julius Center for Health Sciences and Primary
Care, University Medical Center Utrecht; 6Dept of Pathology, University Medical Center Utrecht; 4Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands;
5Surgery NUS and CVRI NUHS, Singapore * Share first authorship
Address for Correspondence:
Gerard Pasterkamp, MD PhD
Experimental Cardiology Laboratory
University Medical Center Utrecht
Heidelberglaan 100, Room G02.523
3584 CX Utrecht, the Netherlands
Tel: (+31)887557155
Fax: (+31)302522693
E-mail: [email protected]
Journal Subject Codes: Atherosclerosis:[135] Risk factors, Stroke treatment - surgical:[76] Carotid endarterectomy, Etiology:[8] Epidemiology
Gert Jan de Borst, MD, PhD2; Frans L. Moll, MD, PhD2; Michiel L. Bots, MMD,D,D, PPhDhDhD33;;;
Gerard Pasterkamp, MD, PhD1
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DOI: 10.1161/CIRCULATIONAHA.113.007603
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Abstract
Background—Time dependent trends in the incidence of cardiovascular disease have been
reported in high-income countries. As atherosclerosis underlies the majority of cardiovascular
diseases, we investigated temporal changes in the composition of atherosclerotic plaques
removed from patients undergoing carotid endarterectomy.
Methods and Results—The Athero-Express study is an ongoing longitudinal vascular biobank
study that includes the collection of atherosclerotic plaques of patients undergoing primary
carotid endarterectomy in the province of Utrecht, the Netherlands from 2002 to 2011.
Histopathological features of plaques of 1583 patients were analysed in intervals of 2 years. The
analysis included quantification of collagen, calcifications, lipid cores, plaque thrombosis,
macrophages, smooth muscle cells, and microvessels. Large atheroma, plaque thrombosis,
macrophages and calcifications were less frequently observed over time with adjusted odds ratios
of 0·72 [0·650-0·789], 0·62 [0·569-0·679], 0·87 [0·800-0·940] and 0·75 (0·692-0·816) per 2 year
increase in time, respectively. These changes in plaque characteristics were consistently
observed in patient subgroups presenting with stroke, transient ischemic attack, ocular symptoms
and asymptomatic patients. Concomitantly, risk factor management and secondary prevention
strategies among vascular patients scheduled for carotid endarterectomy significantly improved
over the past decade.
Conclusions—In conclusion, over the past decade, atherosclerotic plaques harvested during
carotid endarterectomy show a time dependent change in plaque composition characterized by a
decrease in features currently believed to be causal for plaque instability. This seems to go hand
in hand with improvements in risk factor management.
Key words: atherosclerosis, stroke, vascular disease, carotid artery, macrophage, plaque haemorrhage, atheromatous, secular trend
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ncrease in time, , resps ectively. These changes in pplaquq e characteristics were consistently
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DOI: 10.1161/CIRCULATIONAHA.113.007603
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Introduction
Population-based studies demonstrate an age-adjusted decrease in manifestations of
atherosclerotic cardiovascular diseases such as stroke and coronary heart disease over the last
decades in high-income countries.1-5
The composition of atherosclerotic plaques is considered to reflect the local
atherosclerotic disease severity. Indeed, autopsy and clinical pathology studies have revealed that
thin capped atheromatous plaques are associated with rupture resulting in thrombotic occlusion
and a subsequent acute cardiovascular event.6 In addition, a minority of thrombotic events are
caused by plaque erosion in the presence of a fibrous lesion.7
Autopsy studies have provided many insights into the atherosclerotic plaque
characteristics that are associated with cardiovascular events. Yet, there is no report on temporal
changes in plaque phenotypes during the last decades coinciding with the decreased incidence of
cardiovascular disease reported in high-income countries. To investigate time dependent changes
in atherosclerotic plaque characteristics, we used the Athero-Express study, and analyzed
histological features of over 1500 plaques removed during carotid endarterectomy from patients
with similar symptomatology included from 2002 to 2011.
Methods
Athero-Express
Study population
Athero-Express is an ongoing longitudinal biobank study collecting carotid atherosclerotic
plaques from patients that undergo carotid endarterectomy in the University Medical Center
Utrecht or the St Antonius Hospital Nieuwegein, the Netherlands.8 Medical ethics committees of
Autopsy studies have provided many insights into the atherosclerotic plaqaqqueee
characteristics that are associated with cardiovascular events. Yet, there is no report on temporal
chhananangegegess ininin ppplalaquuuee e phphenotypes during the last dececcaaddees coinciding wwwith h thththeee decreased incidence of
caardddioi vascularar dddisi eaeasesee rrepepeporororteteteddd ininn hhhigighh-h-iincooommme cououountririieeses. ToToTo iinvnvveennn ststigigaaatee titimememe ddepeppenenndeded nttt cchahahanngnges
nn aaathththerererososclclclereerototicicc ppplalaqqquee e chchararracaccteteteririristssticiccs,s, wwwe e e usssedede tthhehe AAtAtheheherroro-E-EExpxpprereessssss ssstutudydyd , ananandd anananaaalyzyzzeddd
histological ffeaeaeatutut rereres s s ofofof oooveeerrr 1115000000 plpllaqaqueueu ss s rereremomomoveveved dd dudud ririingngng cccarararotototididi eeendndndarararteteterererectctomomomy y y frfrfromoo patients rr
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both participating centers approved the study and all included patients provided written informed
consent. All patients who underwent carotid endarterectomy from the start of the Athero-Express
in 2002 up to 2011 were included. Patients were excluded from the study if informed consent
was lacking. Indication for surgery was based on international guidelines for symptomatic and
asymptomatic carotid stenosis.9-11 All indications were reviewed by a multidisciplinary team of
vascular specialists before surgery. Patient data were obtained via standardized questionnaires
and pre-operative admission charts.
Plaque processing and assessment
Atherosclerotic plaques of patients were harvested during carotid endarterectomy according to a
standardized and previously reported protocol.8,12 Briefly, carotid plaques were divided into
segments of 5 mm thickness. The section with the largest plaque burden was classified as culprit
lesion and subjected to immunohistochemical staining. Plaques were stained for macrophages
(CD68), smooth muscle cells (alpha-actin), collagen (Picro-sirius Red), microvessels (CD34) and
presence of plaque thrombosis (consisting of the combination of luminal thrombi and/or
intraplaque hemorrhages-haematoxylin eosin and fibrin [Mallory's phosphotungstic acid-
hematoxylin]).8,12,13 Macrophages and smooth muscle cell stains were analysed quantitatively by
computerized analyses and expressed as percentage of plaque area. Plaque neovascularization
was identified by morphological structure with CD34+ staining that was counted in 3 hotspots
and subsequently averaged per cross-section. Collagen and calcifications were scored semi-
quantitatively at a 40X magnification, according to the following criteria: no (1) or minor (2)
staining along part of the luminal border of the plaque or a few scattered spots within the lesion,
moderate (3) or heavy (4) staining was scored when along the entire luminal border or evident
parts within the lesion. Also these categories were binned into no/minor and moderate/heavy for
tandardized and previously reported protocol.8,12 Briefly, carotid plaques were dddiivivididi ededed iiintntnto o o
egments of 5 mm thickness. The section with the largest plaque burden was classified as culprit
eesisiiononon aaandndnd sssubububjeectctcteeded to immunohistochemical stttaaiainniing. Plaques wewew re sstatataiinined for macrophages
CCCDD6D68), smoooththh mmmusscclc e e ceceelllllsss ((a(alplphahaha-a-actctiin), ccooollagggeenn (PPiPicrcroo--ssiiririuuus RRededd),)) mmmiciccroroovevessssselelels s (C(C( DD3D344)4 aand
prpresesesenenencecec ooff f plplp aqaqqueueue tthrhrromommbob sisisiss (((cococonsnnsisistitit ngngng ooof thththe e cococombmbbinnnatatatiiiononn ooff f luuumimim nnnall l ththrororommbmbii ananand//ooror
ntraplaque heheemomom rrrrrrhahah gegeges-s hahahaememematatatoxoxo ylyly innn eeososo ininin anannd dd fifif brbrb innn [[[MaMaMallllororory'yy s phphphosososphphphototo ununngsgsgstititicc c acaca id-
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logistic regression analyses. Size of the lipid core was visually assessed using polarized light and
cut off at 40% of the plaque area, based on the association with rupture prone plaques.14 Luminal
thrombus was defined as a solid mass formed from fibrin and platelets superimposed on the
plaque, within the vascular lumen.15 Loose erythrocytes in the lumen were scored negative for
luminal thrombi. Plaque thrombosis was defined as the combination of either presence of luminal
thrombus and/or intraplaque hemorrhage. Results are also shown separately. All histological
scorings were performed by the same dedicated technician during the entire study period. To
examine whether the assessment of plaque characteristics had changed over time, we performed
additional intraobserver analyses between different time intervals of our longitudinal study.
Definitions of risk factors and medical treatment
At the time of inclusion all patients were asked to complete an extensive questionnaire as
reported previously.5 Systolic blood pressure was measured before surgery in the outpatient
clinic, together with height and length to calculate the body mass index (BMI). Blood withdrawal
was performed at baseline to assess serum total cholesterol and creatinin levels. Creatinin was
used to calculate the estimated glomerular filtration rate (eGFR) with the
Modification of Diet in Renal Disease (MDRD) formula.16 Patients were considered
smokers if they reported to be smoking until the year of inclusion. Diabetic status was restricted
to those patients receiving medical treatment including insulin or oral glucose-lowering drugs.
Statin use at baseline was registered, as well as the use of antihypertensive drugs including
betablockers, ACE-inhibitors, angiotensin II antagonists and diuretics. Furthermore, prescription
of anti-thrombotic medication was registered including aspirin, oral anticoagulants, clopidogrel
and dipyridamol.
For patients undergoing carotid endarterectomy in Athero-Express, the index event was
Definitions of risk factors and medical treatment
At the time of inclusion all patients were asked to complete an extensive questionnaire as
eepopoportrtrtededed ppprererevivv ouuuslslslyy.y.5 Systolic blood pressure wasasas mmmeasured beforrre ee suurgrggeerery in the outpatient d
cllinnnicic, togetherer wwwittth h heheh igigghththt aaandndnd llenennggtgthh tooo calallcuuulateee ttthe bboododyyy mmamasss iinindedexxx ((BBMIMIMI).). BBBlololoododod wwititithdhdhdraraawaw
wawaass s pepeperfrforormememed d aatat bbbasaseeelininne e too aasssssesesessss seserururum mm totototaaall l chchhoololesssteteerororoll l annnd d d ccrcreaeaeatitit nnninn llevevvelells.s.s CCCrereeatiininininn wwwasas
used to calculullatatateee thththe e e esese titit mamaateteed d glglglomomomere ulululararar fffilili trtrtratata ioioi n nn rarar teee (((eGeGeGFRFRFR) ) ) wiwiiththth ttthehehe
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registered as transient ischemic attack, stroke, occular symptoms (including amaurosis fugax or
retinal infarction) or as an asymptomatic status. In addition, the time interval between the last
symptomatic event and surgery was registered.
Follow-up and outcome
The patients included in the Athero-Express study underwent a clinical follow-up that has been
described in detail previously.5 In short, patients were asked to fill in the follow-up questionnaire
after 1, 2 and 3 years. If the questionnaire was answered positively, further research was
performed to investigate the potential outcome of the event. If the patient did not respond, the
general practitioner was contacted. The events were assessed by two members of an outcome
assessment committee. The composite endpoint included any death of presumed vascular origin
(stroke, myocardial infarction, sudden death, other vascular death), non-fatal stroke, myocardial
infarction or any intervention not planned at the time of inclusion.
Statistical analyses
Statistical analyses were performed with SPSS 17.0 (Chicago, IL, USA). To avoid the limitation
of complete case analyses, multiple imputation was used to calculate missing values.17
Supplemental Table 1 gives information on the amount of missingness in our study. To
investigate time trends with sufficient sample sizes in different time periods, we studied plaque
and patient characteristics over 2 year intervals from 2002 to 2011 using Chi-square statistics.
Potential confounding variables were predefined based on observed baseline incomparability
over time (P-value for selection <0.20) and introduced in regression in a step-wise manner to
estimate their individual contribution in logistic regression models. For this analysis, plaque
characteristics were binned into no/minor and moderate/heavy.
assessment committee. The composite endpoint included any death of presumedd vvasasscuuulalalarr r orororiigigiin
stroke, myocardial infarction, sudden death, other vascular death), non-fatal stroke, myocardial
nnfafaarcrcrctititionon ooor r aany y y ininintet rvention not planned at the e ttitimmme of inclusion.n..
SStStatattisi tical annalalyyyseees
StStatatatisisstititicacall anananalalysyssesss wweeeree e pep rfrfforormememed d d wiwiiththh SPSPSPSSSS 11777.000 (C(CChihihicacacagogogo,,, ILILL, USUSU AA)A).. ToToo aaavovov ididid ttthehe limimmititaaatiioon
of complete cacaasesese aaanananalylyyseses s,, mmmuluu tititiplplp ee imimimpupuputatatatititiononon wwwasasa uuusesedd d tototo cccalalalcucuculaaatetete mmmisisissisisingngn vvvalalalueueues.s..171717
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Results
Patients
The demographics in the patient population scheduled for carotid endarterectomy are shown in
Table 1. The mean age at the time of surgery was 66·4 (±8·5) in 2002-2003 and 69·9 (±10·1) in
2010-2011. The proportion of asymptomatic patients in the same period of time was 21·2% for
2002-2003 and 9·2% for 2010-2011. For symptomatic patients, the median time between the last
event and surgery was 111 days [54-159] in 2002-2003 and 20 days [11-35] in 2010-2011
(Table 1). Prevalence of active smoking until the year of surgery was 45·6% in 2002-2003 and
32·1% in 2010-2011. Furthermore, total cholesterol levels at the time of inclusion were lower in
more recent years, concomitant with a higher frequency of statin prescription. The prescription
of angiotensin II antagonists and dipyridamol was also more frequent in more recent years
(Table 2). On the other hand, prescription of oral anticoagulants and clopidogrel were highest in
the early years of the study. These factors were introduced in the multivariate model to assess
their individual contribution to the association between plaque characteristics and year of
inclusion.
Plaque composition
During the past decade the prevalence of plaques with large lipid cores, covering >40% of the
plaque surface, were frequently observed in 2002-2003 (33·2%) and less frequently observed in
2010-2011 (14·4%, p<0·001) (Table 3). The occurrence of plaque thrombosis was more
prevalent in the early years (74·4%) as compared to more recent years (37·6%, p=0·001). There
were no differences in the number of intraplaque vessels over the years. The proportion of
heavily calcified plaques was also less prevalent in more recent years.
Strong fluctuations were observed in macrophage and smooth muscle cell counts between
more recent years, concomitant with a higher frequency of statin prescription. ThThhe prpp esesscrrcripipiptititionon
of angiotensin II antagonists and dipyridamol was also more frequent in more recent years
TaTaablblbleee 2)2)2).. OnOnOn thehee oootht er hand, prescription of oraaal ll aannticoagulants anana d clclclopopopidogrel were highest in
hhhe eae rly years s ofofo ttthee sstuuuddydy.. ThThTheseseee ffafacttoorrs wwwerrre innntrrooduuucceced d innn tthehee mmmululltititivaaaririatatatee e momoodededel l l totoo aaassssseessss
hheieieir r ininindidiviviidududualal cccononntrtriibbuututioion totot ttthehehe aaassssococociaiaiatititiononn bbbetettwweweeenen ppplalalaquququeee cchahaharararactctereriisistiticcscs aaandndd yyyeaearrr ooff
nclusion.
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2002 and 2011. For both cell types the highest values were observed in 2006-2007 and the
lowest values were observed in 2010-2011. The median macrophage percentages were 0·41 % in
2002-2003, and 0·09 % in 2011-2012. Figure 1 shows the semi-quantitative data on plaque
characteristics that are currently believed to be causally related with the vulnerability of the
plaque in two-year intervals. Panel A shows that the decrease in histologically identified plaque
thrombosis was mostly due to a decrease in both luminal thrombosis and intraplaque
hemorrhage. Also, the decrease in plaques with higher fat content coincided with an increase in
plaques with no detectable fat (Figure 1, panel B). For macrophages and calcifications (Figure
1, panel C and D), the heavy staining was less often observed over time whereas minor staining
prevailed in more recent years. Raw scatterplots of macrophages and smooth muscle cells as well
as semi quantitative data on collagen and smooth muscle cells are depicted in eFigure 1.
The association between plaque characteristics and year of surgery was assessed after
adjustment for patient and procedural characteristics that changed over time (age, index event,
delay between event and surgery, medication use) and traditional risk factors that are known to
be associated with atherosclerotic disease progression (presence of contralateral internal carotid
stenosis > 50%, history of peripheral arterial disease, history of coronary arterial disease,
smoking, mean arterial pressure, total cholesterol levels, kidney function (eGFR)). After
adjustment, all aforementioned plaque characteristics, except for smooth muscle cell content
remained significantly associated with year of surgery and indicated an decrease in features that
are considered to be associated with carotid plaque instability over time. Per 2 year increase, the
adjusted odds ratios for atheromatous plaques, plaque thrombosis and calcifications were 0·72
[0·650-0·789] (p<0·001), 0·62 [0·569-0·679] (p<0·001), 0·75 (0·692-0·816) respectively (Figure
2).
prevailed in more recent years. Raw scatterplots of macrophages and smooth musussclclle ee cececellllllss s asasas wwel
as semi quantitative data on collagen and smooth muscle cells are depicted in eFigure 1.
ThThTheee asasssoociciciaatation between plaque characterereriistttics and year oof f f surgrggererery y was assessed after
addjuuusts ment forr ppatatiientntt andndnd ppprororoceceduduurraral chchharacccteeeristtticcs thhhaatat cchahahangngeeded oveverrr ttiimemee (((agage,e, iindndndeexx eeeveventntnt,,
dedelalalay y y bebeb twtwweeeeeenn evevveennt t aananddd susurgrggererryyy, mmmededicici atatatioioion n usususe)e)e) aanandd d trtrradadadiiitioioonananal l riririsksks fffaccctotorsrsrs ttthahah tt t ararare kknknowowo nnn totoo
be associated d wiwiwiththh aaathththerererososclclclerererottticicic dddisisi eaaasesese ppprororogrgrgresesssisis onono ((prprpresesesenenencecece oof f f cococontntntrararalalalateterararal l l ininnteteternrnr al carotid
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Step-wise introduction of these patient characteristics and use of medication to the
regression model with either atheromatous plaques, plaque thrombosis and calcifications as an
outome revealed that none of these factors could be considered as confounding variables (change
in beta <10%). The Supplemental Table 2 shows the odds ratios of the association between
plaque and year of inclusion, following a step-wise correction for potential confounders.
Supplemental Table 3 shows the adjusted odds ratio for subgroups without statin use, blood
pressure medication and smoking. Table 4 depicts the time dependent changes in plaque
characteristics for each clinical presentation before surgery. The data reveal that the temporal
changes in plaque characteristics were consistent among these subgroups. During 3 years of
follow-up, event rates for composite cardiovascular endpoints remained similar. Of those
included in 2002-2003, 31·7% had experienced a major cardiovascular endpoint within 3 years
compared to 26·4% of those included in 2008 (Kaplan Meier plots are shown in eFigure2).
Discussion
The current study shows time dependent changes towards more plaques that show features
currently believed to be associated with plaque stability in carotid endarterectomy patients. This
coincided with more favorable cardiovascular risk factor levels and more prescription of
medications. Our data do not prove that more favorable risk factor levels or medication in the
last decade caused the time dependent changes in plaque characteristics. We can only conclude
that risk factors and plaque composition improved concurrently over the years.
Changes in cardiovascular disease morbidity and mortality in populations over decades
have been documented.1,2,4,5 For both, stroke and coronary heart disease favorable time trends in
incidence and mortality have been reported in high-income countries.1,2,4,5 These temporal
follow-up, event rates for composite cardiovascular endpoints remained similar. OfOfOf tthohohoseese
ncluded in 2002-2003, 31·7% had experienced a major cardiovascular endpoint within 3 years
coompmpmparararededed ttto oo 2226·4·44%%% of those included in 2008 (KKKapapa llan Meier plottsss are e shshshowo n in eFigure2).
DiDiiscscscususussisis ononn
The current ststtudududy y y shshshowowws ss tiiimememe ddepepepenenndeded ntntn ccchahahangngngeseses tototowaww rdrdrds s momomorerere ppplaaaquququeseses ttthahahat t shshhowowow fffeaeae tures
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changes are thought to be related to more favorable risk factor profile in populations both before
and after the event. Our study shows similar trends in risk factor levels and medication
prescription in carotid endarterectomy patients from 2002 to 2011. We observed a decrease in
total cholesterol, improved mean arterial pressure and a decrease in the prevalence of smoking in
more recent years. Also, an increase in the prescription of statins and angiotensin II receptor
antagonists in more recent years was observed. Controversially, the lower number of plaques that
show features currently believed to be associated with plaque instability together with a more
favorable risk factor level and increased medication did not coincide with a shift towards less
severe events before the patients were scheduled for carotid endarterectomy in our carotid
endarterectomy population. On the contrary, the inclusion of asymptomatic patients in our
cohort even decreased over time. In addition, the more recent included carotid endarterectomy
patients demonstrated similar event-free survival in the 3-year follow-up after surgery compared
to patients included in the early years of the Athero-Express study. These results show that
primary prevention measures may have improved the last decade coinciding with plaques that
show features currently believed to be associated with plaque stability. Yet, this did not translate
into a reduced event rate in patients with severe carotid artery disease. The time dependent
changes in plaque characteristics without subsequent reduction in inclusion rate or secondary
manifestations of atherosclerotic disease is of interest since it might challenge the current
concept that the unstable vulnerable plaque is the major determinant of outcome in patients
suffering from carotid artery disease.
Multiple studies suggest that the stroke population is changing in terms of severity of the
disease and stroke subtypes.18-21 A registry study spanning a 25-year time period shows that
stroke patients were less likely to suffer from large artery disease with and without significant
endarterectomy population. On the contrary, the inclusion of asymptomatic patitieeentststs iinn n ououourr r
cohort even decreased over time. In addition, the more recent included carotid endarterectomy
paatitiienenentststs dddemememooonststtrararateted similar event-free survivaaal l l ininn the 3-year foollllloww-u-uupp p after surgery compared
oo pppaatients inclcludududeedd iiinn n thhhe e eaeaearlrlrly y yeyeearararss ofoff the AAAtherroro--Expxpxpreresss sstutuddydy. ThThheesesee rereesusuultltss shshshowowo thahahat t
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stenosis.19 In the Netherlands, a remarkable decline in fatal ischemic stroke has been observed in
the last twenty years.18 This trend was not only observed following stroke in the Netherlands but
also for coronary heart disease.22
Our data support the idea that the underlying mechanism explaining cerebral
manifestations of atherosclerotic disease may be changing. Inevitably, our findings question the
validity of the vulnerable plaque hypothesis in this population. The carotid endarterectomy
patients in our study were being referred to the hospital with major events such as stroke, also in
the more recent years. Yet, their atherosclerotic plaque removed during surgery show features
currently believed to be associated with plaque stability. Although the symptomatic plaques
revealed more stable characteristics in recent years, we did not observe secular trends in the
proportion of patients with contralateral internal artery stenosis. This suggests that the observed
changes in composition of atherosclerotic plaques come without changes in the extent of
atherosclerotic disease.
Changes in patient demographics over time included increasing age, decreasing delay
between surgery and the last event, and changes in symptomatic status since we included less
asymptomatic patients. These changes in our population even strengthen the validity of our
findings. The older age of patients undergoing carotid endarterectomy during the inclusion
period might have several explanations. One might hypothesize that patients suffer from stroke at
an older age, as progression of atherosclerotic disease has been slowed down due to successful
improvements in primary prevention.23 On the other hand, overall prognosis and life expectancy
of individuals is improving, thereby allowing selection criteria for carotid revascularization to be
extended. Finally, elderly patients seem to have increased risks during carotid stenting as
compared with younger patients.24-27 These results from large randomized trials over the past
evealed more stable characteristics in recent years, we did not observe secular trtrrenenenddsd iin n thththeee
proportion of patients with contralateral internal artery stenosis. This suggests that the observed
chhananangegegess ininin ccooompopopossisitit on of atherosclerotic plaqueuees s cccome without ccchah ngnggeseses in the extent of t
attheeeror sclerotic c didd sseeasaseee.
ChChananangeges s ininn ppatattieentnt demememogogogrararapphphiiicscss ooovvever r tititimmme iincccluuudedededdd ininincrcrreaaasisisingngg aagegeg , dedeecrcreaeaeasssingngg dddelelayayay
between surgrggererery y y ananandd d thththe ee laaaststs eeeveveentntn ,, anaa d d d chchhananangegeges s ininin sssymymy ptptptomomomatatticicic sstaaatututusss sisisincncnce e e wewewe iincncncluluuded less
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12
years, might have resulted in more frequent referral of elderly to undergo carotid
endarterectomy, instead of carotid stenting. Older age has been reported to be associated with
plaque characteristics currently believed to be associated with plaque instability.28,29
Controversially, in our study the plaques showed more features considered to reflect stable
plaques despite the fact that the patients became older at inclusion. Also, the delay between the
last event and surgery has decreased significantly, because timing of carotid endarterectomy is
essential in the prevention of secondary stroke.30 This has resulted in adjustments of guidelines
and, in our experience, shortening in referral delay. It has previously been shown that plaques
from patients operated on shortly after stroke reveal more inflammatory and thus unstable
characteristics, including macrophages and inflammatory proteins.31,32 Based on these previous
observations one would expect a higher prevalence of plaques with more features associated with
plaque instability in patients undergoing carotid surgery. Nevertheless, we observed a
stabilization of plaques in the last decade suggesting that the plaque differences over time are not
driven or confounded by shortening of the timing of surgery. Carotid endarterectomy for
asymptomatic individuals has been debated for long, and especially in recent years due to
improvements in medical treatment. Indications for surgery have likewise been changed over the
past decade, and a conservative approach for most asymptomatic patients is now proposed by
neurologists and vascular surgeons. Plaques from asymptomatic patients have a more fibrous and
lees inflammatory phenotype as compared with TIA and stroke patients.33 We observed more
plaques with more fibrotic and less inflammatory features whilst the proportion of asymptomatic
patients was lower. Furthermore, our findings is supported by our subgroup analyses that shows
that the time dependent changes in plaque characteristics were very consistent in the well-
defined 4 patient groups presenting with either a stroke, transient ischemic attack, ocular
characteristics, including macrophages and inflammatory proteins.31,32 Based on n thtthesee ee prprprevevevioioiousu
observations one would expect a higher prevalence of plaques with more features associated with
pllaqaqaqueueue iiinsnsstatatabibib litytyy iiinn patients undergoing carotid d susus rrrgery. Nevertheheelesss, , wwwe observed a
ttabbbili ization ofof ppplaaaquueees iiinn thththeee llalastst ddeececaadadee suuggggestiinngg thahahatt ththhe plplaaaquueue dddififi fefeererencncnceses ooovevever r r tititimememe aarrre not
drdrivivivenenn oorr cococonfnnfououundnddeded bbyy y shshororrtetenininingngng ooff f thhhee e tititimimimingngng ooff ssururu gegegeryryry. CCCaararotototididi eeenndndararrtetet rererectcttomomomy y fofoor r
asymptomaticicc iindndndivivivididi uauauals hhhasasas bbbeeeeeen n dedd bababateteted d d fofofor r r loloongngng, , , anannd d d esesespepepecicicialaa lyyy iin n n rererecececentntn yyyeaeaearsrsrs dddueu to
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13
symptoms or those who were asymptomatic. We have performed several analyses in which we
were unable to detect variables that confounded the relation between inclusion year and plaque
phenotype.
Limitations
Bias in the study of time dependent trends may occur when for example the diagnosis of the
disease has changed. Changes in detection of the disease may result in the phenomena like Will
Rogers (an increased incidence of the disease and lower rates of case-fatality).34 We did not
observe a decline in the total number of patients included or a shift towards less symptomatic
patients in the Athero-Express study. However, we cannot exclude that our observations over
time could be due to the differences in patient characteristics and indications for surgery that
have occurred over this same interval. The observational nature of this study merits careful
consideration and before making causal inferences this observation requires serial imaging
plaque characterization measurements in patients. In addition, the awareness among patients that
mild and transient symptoms may be due to a minor stroke or a transient ischemic attack may
have been improved. For example, as in many countries, repetitive educational campaigns were
raised in the Netherlands by the Dutch Heart Foundation in the late 1990s focusing on
recognition of early signs and symptoms of stroke and transient ischemic attacks. This may have
led to the aforementioned inclusion of less-severe diseased patients in our study with
concomitant different plaque characteristics. In part of the histological analyses we applied
arbitrary cut off values to categorise plaque phenotypes. This may have influenced our
observations. However, also computerized quantitative measurements such as CD68 revealed a
consistent change towards plaque stabilization over time. In addition, the interpretation of plaque
patients in the Athero-Express study. However, we cannot exclude that our obsererrvavavatitit ononns s ovovoverere t
ime could be due to the differences in patient characteristics and indications for surgery that
haaveveve ooocccccurururrerer ddd ovovvererer this same interval. The obsererrvavav ttional nature ofoff thiiss stststudu y merits careful rrr
coonnsnsideration anand d bebebefofoforeee mmmakakakiiingng cccauauausaal infeeereeencees tthisss oobobsseerrvavattiioonn rreqeqquuiireress s sseseririalalal iiimamam giginngng
plplaqaqaqueueue cchahaarararactctererizizatata ioioonn memem asssururu emememenenentsts iin nn papapattienenentsts.. IInn aaaddddditititiioion,n,n, ththhe awawawaararenennesessss amamamononongg g papaatiienentstss tthhahat
mild and transnssieieientntt sssymymymptptp ommms s s mamamay y y bebebe dddueueu ttto o o a a a mimim nononor r r sts rorookekeke ooor r a a a trtrt annnsisisienenent t t isisischchc emememicicic aaattttttaca k may
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characteristics has been performed by the same dedicated technician over the entire study period
to ensure continuity. The scoring system that was used has previously been validated by an
additional observer and an independent pathologist.12 Although we cannot fully exclude that
changes over time are caused by misinterpretations we feel that the strong consistency in the data
and different stains support our view that carotid symptomatic lesions show stabilization features
over the last decade.
In conclusion, over the past decade, atherosclerotic plaques harvested during carotid
endarterectomy show a time dependent change in plaque composition characterized by a
decrease in features currently believed to be causal for plaque instability. This seems to go hand
in hand with improvements in risk factor management.
Acknowledgments: Drs. Van Lammeren, Den Ruijter and Pasterkamp had full access to all of
the data in the study and take responsibility for the integrity of the data and the accuracy of the
data analysis. Role of the sponsor: The funding sponsor was not involved in the design and
conduct of the study; collection, management, analysis and interpretation of the data; and
preparation, review, or approval of the manuscript. Author Contributions: Drs Van Lammeren,
Den Ruijter and Pasterkamp had full access to all the data in the study and take responsibility for
the integrity of the data and the accuracy of the data analysis. Study concept and design: Van
Lammeren, de Kleijn, Moll, Pasterkamp. Acquisition of data:, Van Lammeren, Vrijenhoek, van
der Laan, De Borst, De Vries. Analysis and interpretation of the data: Van Lammeren, Den
Ruijter, van der Laan, Vrijenhoek, Velema, Vink. Drafting of the manuscript: Van Lammeren,
Den Ruijter. Critical revision of the manuscript for important intellectual content: Pasterkamp,
Moll, Vink, De Vries, de Kleijn, De Borst, Bots. Statistical analysis: Van Lammeren, Den
Ruijter, Bots. Obtained funding: Pasterkamp, Moll, de Kleijn. Administrative, technical or
material support: Vrijenhoek, Velema. Study supervision: Pasterkamp
Funding Sources: This project was funded by the University Medical Center Utrecht.
n hand with improvements in risk factor management.
Acknknnowowowleleledgdgdgmementntntss: Drs. Van Lammeren, Den RRRuiuiuijtjj er and Pasterkammppp hahh d full access to all of
hhhee dddatat in thhheee sttudududy y anannd d d tatatakekk rresesespopoponsnsibibililitty y y fofor ththe iinteegrgrgrititityy y of ttthhehe ddata aa aaandn tthehee aaaccccc ururacacyy y ofoff tttheheh
dadad taaa analysis. Roooleee of f ththhe sppononnsos r:: TTThehee fffundddinnng spopoponnsoror wwwaaas nnott innnvolvvvedd ininn ttthehe ddeeesigigi nnn aannd drr
coondndnducucuctt ofoff tttheheh ssttutuddydy;; cocolllleectitiiononon, mamamananagegegemememenntnt, , anana aalalyysysiisis aaandndnd intntntererrprprpretetetaatitiionnn oof f f ththhee dadadattata;; aanandd d
prprprepepeparararatatatioioionnn, rrrevevevieieiewww, ooorrr aaapppppprororovavavalll ofofof ttthehehe mmmanananusususcrcrcripipipttt. AuAuAuthththororor CCCononontrtrtribibibutututioioionsnsns::: DrDrDrsss VaVaVannn LaLaLammmmmmerererenenen,
DeDenn RuRuijijteterr anandd PaPaststererkakampmp hhadad ffululll acaccecessss ttoo alalll ththee dadatata iinn ththee ststududyy anandd tatakeke rresespoponsnsibibililitityy foforr
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Conflict of Interest Disclosures: None.
References:
1. Rothwell PM, Coull AJ, Giles MF, Howard SC, Silver LE, Bull LM, Gutnikov SA, Edwards P, Mant D, Sackley CM, Farmer A, Sandercock PAG, Dennis MS, Warlow CP, Bamford JM, and Anslow P. Change in stroke incidence, mortality, case-fatality, severity, and risk factors in Oxfordshire, UK from 1981 to 2004 (Oxford Vascular Study). Lancet. 2004;363:1925-1933.
2. Carandang R, Seshadri S, and Beiser A. Trends in incidence, lifetime risk, severity, and 30-day mortality of stroke over the past 50 years. JAMA. 2006;296:2939-2946.
3. Sytkowski PA, Kannel WB, and D'Agostino RB. Changes in Risk Factors and the Decline in Mortality from Cardiovascular Disease. N Engl J Med. 1990;322:1635-1641.
4. Tunstall-Pedoe H, Vanuzzo D, Hobbs M, Mähönen M, Cepaitis Z, Kuulasmaa K, and Keil U. Estimation of contribution of changes in coronary care to improving survival, event rates, and coronary heart disease mortality across the WHO MONICA Project populations. Lancet.2000;355:688-700.
5. Sytkowski PA, D'Agostino RB, Belanger A, and Kannel WB. Sex and Time Trends in Cardiovascular Disease Incidence and Mortality: the Framingham Heart Study, 1950-1989. Am J Epidemiol. 1996;143:338-350.
6. Finn AV, Nakano M, Narula J, KOLODGIE FD, and Virmani R. Concept of Vulnerable/Unstable Plaque. Arterioscler Thromb Vasc Biol. 2010;30:1282-1292.
7. Burke AP, Farb A, Malcom GT, Liang Yh, Smialek J, and Virmani R. Coronary Risk Factors and Plaque Morphology in Men with Coronary Disease Who Died Suddenly. N Engl J Med.1997;336:1276-1282.
8. Verhoeven B, Velema E, Schoneveld A, Vries J, de Bruin P, Seldenrijk C, Kleijn D, Busser E, der Graaf Y, Mol F, and Pasterkamp G. Athero-express: Differential atherosclerotic plaque expression of mRNA and protein in relation to cardiovascular events and patient characteristics. Rationale and design. Eur J Epidemiol. 2004;19:1127-1133.
9. Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial. Lancet. 2004;363:1491-1502.
10. Barnett HJM, Taylor DW, Eliasziw M, Fox AJ, Ferguson GG, Haynes RB, Rankin RN, Clagett GP, Hachinski VC, Sackett DL, Thorpe KE, Meldrum HE, and Spence JD. Benefit of Carotid Endarterectomy in Patients with Symptomatic Moderate or Severe Stenosis. N Engl J Med. 1998;339:1415-1425.
11. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of
g y p g , ,coronary heart disease mortality across the WHO MONICA Project populations.s. LaLaLancncnceetet..2000;355:688-700.
5. Sytkowski PA, D'Agostino RB, Belanger A, and Kannel WB. Sex and Time Trends inCardrdioioiovavavascscsculullara DDDisisiseease Incidence and Mortality:y:y: ttthehh Framingham Heearararttt StS udy, 1950-1989. Am JEpEppididideememioll.. 191919966;1;14343:333838-3350..
6..6 FFFiinn AV, Nakkkannno MMM, Narrurullala JJ, KOKKOLOLOLODGGGIEEE FD,D,D andndd VVViririrmmmannii RRR. Cooonnccepppt ofof VuVuVulnnnereraba le/U/UUnsnsn ttaabblblee PPPlaaqaqueue. . . AArArteteririiosooscccleerer TThhrhromombbb VaVascssc BBioiool.. 20201000;3; 0:122282822-1-129292.2.
777. BBBurururkekeke AAAPP,P, FFFarararbbb AAA, MMMalalalcococommm GTGTGT, LiLiLianananggg YhYhYh, SmSmSmiaiaialelelekkk JJ,J, aaandndnd VVViririrmamamaninini RRR. CoCoCorororonananaryryry RRRisisiskkk FaFaFactctctorororsssand Plaqque MMMorororphphphololologogogy y y ininn MMMenen wwwititthh h CoCoCororonanan ryryry DDDisisseaeaasese WWWhohoho DDDieiei d d SuSuSuddddddenenenlylyl . NNN EnEnEnglglgl JJ Med.
by guest on March 17, 2018
http://circ.ahajournals.org/D
ownloaded from
DOI: 10.1161/CIRCULATIONAHA.113.007603
16
the MRC European Carotid Surgery Trial (ECST). Lancet. 1998;351:1379-1387.
12. Hellings WE, Pasterkamp G, Vollebregt A, Seldenrijk CA, de Vries JP, Velema E, de Kleijn DPV, and Moll FL. Intraobserver and interobserver variability and spatial differences in histologic examination of carotid endarterectomy specimens. J Vasc Surg. 2007;46:1147-1154.
13. Hellings WE, Peeters W, Moll FL, Piers SRD, van Setten J, Van der Spek PJ, de Vries JP, Seldenrijk KA, De Bruin PC, Vink A, Velema E, de Kleijn DPV, and Pasterkamp G. Composition of carotid atherosclerotic plaque is associated with cardiovascular outcome. Circulation. 2010;121:1941-1950.
14. Davies M, Richardson P, Woolf N, Katz D, and Mann J. Risk of thrombosis in human atherosclerotic plaques: role of extracellular lipid, macrophage, and smooth muscle cell content. Br Heart J. 1993;69:377-381.
15. Schwartz SM, Galis ZS, Rosenfeld ME, and Falk E. Plaque Rupture in Humans and Mice. Arterioscler Thromb Vasc Biol. 2007;27:705-713.
16. Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A More Accurate Method To Estimate Glomerular Filtration Rate from Serum Creatinine: A New Prediction Equation. Ann Int Med. 1999;130:461-470.
17. Janssen KJM, Donders AR, Harrell J, Vergouwe Y, Chen Q, Grobbee DE, and Moons KGM. Missing covariate data in medical research: To impute is better than to ignore. J Clin Epidemiol.2010;63:721-727.
18. Vaartjes I, O'Flaherty M, Capewell S, Kappelle J, and Bots M. Remarkable Decline in Ischemic Stroke Mortality is Not Matched by Changes in Incidence. Stroke. 2013;44:591-597.
19. Carrera E, Maeder-Ingvar M, Rossetti AO, Devuyst G, and Bogousslavsky J. Trends in Risk Factors, Patterns and Causes in Hospitalized Strokes over 25 Years: The Lausanne Stroke Registry. Cerebrovasc Dis. 2007;24:97-103.
20. Benatru I, Rouaud O, Durier J, Contegal F, Couvreur G, Bejot Y, Osseby GV, Ben Salem D, Ricolfi F, Moreau T, and Giroud M. Stable Stroke Incidence Rates but Improved Case-Fatality in Dijon, France, From 1985 to 2004. Stroke. 2006;37:1674-1679.
21. Appelros P, Jonsson F, Asplund K, Eriksson M, Glader EL, Asberg K, Norrving B, Stegmayr B, and Terént A. Trends in Baseline Patient Characteristics during the Years 1995-2008: Observations from Riks-Stroke, the Swedish Stroke Register. Cerebrovasc Dis. 2010;30:114-119.
22. Vaartjes I, O'Flaherty M, Grobbee DE, Bots ML, and Capewell S. Coronary heart disease mortality trends in the Netherlands 1972-2007. Heart. 2011;97:569-573.
23. Romano JG, Imrey PB, and Sacco RL. Further Good News on Stroke, but No Time for Rest.
16. Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A More Accururaatateee MeMeMeththhododod TTo Estimate Glomerular Filtration Rate from Serum Creatinine: A New Prediction EEquququaatatioioonnn. AnAAnnn InInIMed. 1999;130:461-470.
177. . JaJaJannsnsseseenn n KJKK M,M,M DDDonders AR, Harrell J, Vergouououwwee Y, Chen Q, GrGG obbbebebeee DE, and Moons KGMMMiMisssssini g covavaarriatatee e dadatata iiin n memem didicacacalll rereseseararchch:: ToTo iimmpmpuute isiss bbbetete ter r thththaanan ttoo igigignoorere.. JJJ ClClC inin EEpipip dededemimim olo .22001100;63:721-727227.77
1888. VaVaVaarara tjtjjeseses III, , OO''FFllahaheeertytyty MM, CaCaCapepepewewwelllll SSS,, KKKappppppeelllllee J,J, aandndnd BBBototots ss MM.M. RRRememmaararkakaablblble ee DeDeDecclclinnnee inini schhememiic SStrt okke e MoMortrtalitty y is NNotot MMatchheded bby y ChChangegess inin IIncncididenncece. StStrokeke. 20201313;44:4:595 1-1-59597.
1919 CaCarrrrereraa EE MMaeaedederr-InIngvgvarar MM RoRossssetettiti AAOO DDevevuyuysstt GG aandnd BBogogouousssslalavsvskyky JJ TrTrenendsds iinn RiRisksk
by guest on March 17, 2018
http://circ.ahajournals.org/D
ownloaded from
DOI: 10.1161/CIRCULATIONAHA.113.007603
17
Circulation. 2011;123:2066-2068.
24. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial. Lancet. 1920;375:985-997.
25. Eckstein HH, Ringleb P, Allenberg JR, Berger J, Fraedrich G, Hacke W, Hennerici M, Stingele R, Fiehler J, Zeumer H, and Jansen O. Results of the Stent-Protected Angioplasty versus Carotid Endarterectomy (SPACE) study to treat symptomatic stenoses at 2 years: a multinational, prospective, randomised trial. Lancet Neurol. 2008;7:893-902.
26. Hobson II RW, Howard VJ, Roubin GS, Brott TG, Ferguson RD, Popma JJ, Graham DL, and Howard G. Carotid artery stenting is associated with increased complications in octogenarians: 30-day stroke and death rates in the CREST lead-in phase. J Vasc Surg. 2004;40:1106-1111.
27. Mas JL, Trinquart L, Leys D, Albucher JF, Rousseau H, Viguier A, Bossavy JP, Denis B, Piquet P, Garnier P, Viader F, Touzé E, Julia P, Giroud M, Krause D, Hosseini H, Becquemin JP, Hinzelin G, Houdart E, Hénon H, Neau JP, Bracard S, Onnient Y, Padovani R, and Chatellier G. Endarterectomy Versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis (EVA-3S) trial: results up to 4 years from a randomised, multicentre trial. Lancet Neurol.2008;7:885-892.
28. van Lammeren GW, Reichmann BL, Moll FL, Bots ML, de Kleijn DPV, de Vries JP, Pasterkamp G, and De Borst GJ. Atherosclerotic Plaque Vulnerability as an Explanation for the Increased Risk of Stroke in Elderly Undergoing Carotid Artery Stenting. Stroke. 2011;42:2550-2555.
29. Redgrave JNE, Lovett JK, and Rothwell PM. Histological Features of Symptomatic Carotid Plaques in Relation to Age and Smoking: The Oxford Plaque Study. Stroke. 2010;41:2288-2294.
30. Rothwell PM Warlow CP. Prediction of benefit from carotid endar terectomy in individual patients: a risk-modelling study. Lancet. 1999;353:2105-2110.
31. Peeters W, Hellings WE, de Kleijn DPV, de Vries JPPM, Moll FL, Vink A, and Pasterkamp G. Carotid Atherosclerotic Plaques Stabilize After Stroke: Insights Into the Natural Process of Atherosclerotic Plaque Stabilization. Arterioscler Thromb Vasc Biol. 2009;29:128-133.
32. Redgrave JNE, Lovett JK, Gallagher PJ, and Rothwell PM. Histological Assessment of 526 Symptomatic Carotid Plaques in Relation to the Nature and Timing of Ischemic Symptoms: The Oxford Plaque Study. Circulation. 2006;113:2320-2328.
33. Verhoeven B, Hellings WE, Moll FL, de Vries JP, de Kleijn DPV, de Bruin P, Busser E, Schoneveld AH, and Pasterkamp G. Carotid atherosclerotic plaques in patients with transient ischemic attacks and stroke have unstable characteristics compared with plaques in asymptomatic and amaurosis fugax patients. J Vasc Surg. 2005;42:1075-1081.
JP, Hinzelin G, Houdart E, Hénon H, Neau JP, Bracard S, Onnient Y, Padovani RR,, ananand d ChChatatelellil erG. Endarterectomy Versus Angioplasty in Patients with Symptomatic Severe Cararrototididi SSStetetenononosisisis sEVA-3S) trial: results up to 4 years from a randomised, multicentre trial. Lancetet NNNeeueurorolll.
2008;7:885-892.
288. . vavavannn LaLaLammmmmmerrenenen GGW, Reichmann BL, Moll FLFLFL, BBots ML, de KlKlK eijnjn DDDPVP , de Vries JP, PaPaasttteerkak mpp GGG, anannd d d DeDe BBBorororststs GGJ.J.J. AAAththererososclclererototicic PlPlPlaaqueuee VVVululu neerararabibib lilityty aaas s s ann EExpxpxplalal nanatitiononon ffororor ttheh nncrrreae sed Riskk oof StStrorookekee iiinnn ElElElddederlrllyy y UnUnnddeergoooinnng CCCaarrotididid AArrrteerryy SStStenentitiinnng. StStrororokkeke. 202020111111;4;; 2:2:2:255255000-
2525555555.
29. ReRedgd raravev JJNENE,, LoLovetttt JK,K aandnd Rothwhwelell l PMPM. Histstolologogicicalal Feaeatutureres s off SSymymptptommatatic CCararoto idid Plaques in RRelellatatatioioon n n tototo AAAgegee aandnn SSSmomomokikk ngngng::: ThThTheee OxOxOxfofofordrdr PPPlalalaququque ee StStStuduu y.y.y. StStStrororokekeke.. 20200101010;4;441:1:1 2288-22944.
by guest on March 17, 2018
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34. Feinstein AR, Sosin DM, and Wells CK. The Will Rogers Phenomenon - Stage Migration and New Diagnostic Techniques as a Source of Misleading Statistics for Survival in Cancer. NEngl J Med. 1985;312:1604-1608.
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Table 1. Patient characteristics over time.
Patient characteristics 2002-2003 (n=250)
2004-2005 (n=408)
2006-2007 (n=352)
2008-2009 (n=332)
2010-2011 (n=271)
P value
Age, mean (±SD) 66·4 (8·50) 68·3 (9·3) 68·7 (9·2) 69·7 (8·9) 69·9 (10·1) <0·001 Gender, male, % 69·2 70·3 67·9 67·2 67·2 0·357 Smoking, % 45·6 33·1 33·8 30·4 32·1 0·003 Diabetes, % 21·2 22·1 25·6 19·3 22·1 0·893 Mean arterial pressure, mmHg (±SD) 107·9 (±14·7) 107·9 (±15·6) 107·2 (±16·3) 107·7 (±16·9) 104·5 (±15·1) 0·023 Total cholesterol, mmol/ml (±SD) 5·2 (±1·1) 4·7 (±1·2) 4·4 (±1·1) 4·4 (±1·2) 4·9 (±1·2) 0·002 eGFR, ml/min/1·73m2 (±SD) 71·5 (±18·6) 70·3 (±19·8) 72·7 (±22·8) 71·3 (±20·2) 73·5 (±19·9) 0·157 Body mass index, kg/m2 (±SD) 26·4 (±3·8) 26·2 (±3·9) 26·5 (±3·7) 26·1 (±3·4) 26·7 (±4·6) 0·525 Time since last cerebrovascular event, days, median [IQR] 111 [54-159] 65 [26-121] 44 [18-72] 30 [13-53] 20 [11-35] <0·001 Index event <0·001 Asymptomatic, % 21·2 17·2 13·9 10·8 9·2 Ocular, % 14·8 12·5 14·8 16·9 20·7 Transient ischemic attack, % 40·0 45·3 50·9 44·6 43·2 Stroke, % 24·0 25·0 20·5 27·7 26·9 Contralateral internal carotid stenosis > 50% 46·0 41·2 47·4 45·2 51·7 0·072 History of peripheral arterial disease 26·0 19·6 19·3 22·0 17·7 0·115 History of coronary arterial disease 37·2 28·7 31·5 30·7 29·2 0·188 Abbreviations: SD, standard deviation; IQR, interquartile range. P-value
cholesterol, mmol/ml (±SD) 5·2 (±1·1) 4·7 (±1·2) 4·4 (±1·1) 4·4 (±1 2·2))) 4·4·4 999 (±(±(±1·1·1 2)2)2), ml/min/1·73m2 (±SD) 71·5 (±18·6) 70·3 (±19·8) 72·7 (±22·8) 71·3 ±(± 0202 ·22) ) ) 73737 ·55·5 (((±1±1±19·9·9)9)mass index, kg/m2 (±SD) 26·4 (±3·8) 26·2 (±3·9) 26·5 (±3·7) 26·1 (±3±3 4·4·4))) 262626·77·7 ((±4±4± ·6·66) ) )since last cerebrovascular event, days, median [IQR] 111 [54-159] 65 [26-121] 44 [18-72] 30 [13-53] 20 [11-35] event ptomata icic, , % % 21·2 17·2 13·9 10·8 9·2 r, , % % % 14·8 12·5 14·8 16·9 20·7 ii nenent isisischchemic aattttacacack, %% 40·0·0 445·5 33 505 9·9 444·4·66 43·2 ee, % 2422 00·0 2225·5·5·00 0 202020·5·5 22277·7·777 262626·9·9 aala eeteraral internal carot didid stet nossisi >>> 50%0% 446·000 414141·2·2 447·4 4545·22 511·7 77rryyy ffof pperipheral arartett ri lala ddisi ea ees 2622 00·0 1119·9·9·66 19·3 222·2 0 17 77·7ryy ofofof ccorororononarary y ararartetet ririalal dd ssiseaeasese 3733 22·2 228·8·8 77 313131·5·5· 3330·0 77 2929 2·2·2viatiionons:s: SSSDDD, sstatat ndnd rard d ddede ivivi tatatioioi n;n; IIIQRQRQR, ininterqrquauartrtrtililile e e rarange. PP v-v-valalalueue
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Table 2. Preoperative medication prescription over time.
Prescribed preoperative medication 2002-2003 (n=250)
2004-2005(n=408)
2006-2007(n=352)
2008-2009(n=332)
2010-2011(n=271)
P value
Statins, % 64·8 73·3 81·2 78·6 79·3 <0·001 Betablockers, % 46·0 47·5 44·3 46·7 42·8 0·417 ACE-inhibitors, % 30·0 34·1 33·0 26·8 33·2 0·707 Angiotensin II antagonists, % 18·4 18·1 22·2 24·1 26·2 0·004 Diuretics, % 31·2 35·0 35·8 38·3 33·6 0·388 Aspirin, % 87·6 85·5 84·4 83·7 84·9 0·289 Oral anticoagulants, % 14·4 11·8 13·6 12·0 9·2 0·137
tics, % 31·2 35·0 35·8 38·3 33333·6·66 00·38in, % 87·6 85·5 84·4 83·7 84844·9·9 00·28anticoagulants, % 14·4 11·8 13·6 12·0 99·2·2 000·1·1333
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Table 3. Presence of atherosclerotic plaque components over time.
Plaque Composition 2002-2003 (n=250)
2004-2005(n=408)
2006-2007(n=352)
2008-2009(n=332)
2010-2011(n=271)
P value
Atheromatous plaque (lipid core > 40% of plaque surface), % 33·2 36·0 26·7 21·1 14·4 <0.001
Plaque thrombosis, % 74·4 75·5 62·5 49·1 37·6 <0.001
Intraplaque vessels, median [IQR] 6·7[4·3-10·4]
8·5[5·7-12·3]
7·7[4·7-11·9]
7·3[3·7-12·9]
6·3[2·3-11·7] 0.436
Collagen rich, % 73·6 85·8 80·1 76·8 78·6 0.643 Median % macrophage staining per plaque area [IQR]
0·41[0·09-1·30]
0·46[0·08-1·23]
1·04[0·46-1·96]
0·27[0·10-0·64]
0·09[0·01-0·51] <0.001
Median % smooth muscle cell staining per plaque area [IQR]
2·03[0·73-4·34]
1·08[0·34-2·65]
2·19[1·00-3·75]
1·23[0·46-2·21]
0·68[0·13-1·99] <0.001
Calcified plaque, % 52·0 62·0 59·7 51·2 24·0 <0.001 Abbreviations: IQR, interquartile range.
plaque vessels, median [IQR] [4·3-10·4] [5·7-12·3] [4·7-11·9] [3·7-12·9] [2[22·3·3·3-1-11·1·7]7] 0.43
gen rich, % 73·6 85·8 80·1 76·8 778·8·8 666 0.0 64an % macrophage staining per plaque area ]
0·41[0·09-1·30]
0·46[0·08-1·23]
1·04[0·46-1·96]
0·27[0·10-0·64]
0·0·0 09099[0·01-0·51] <00.0
an % smooth muscle cell staining per plaqueIQR]R]
2·03[0·73-4·34]]
1·08[0[0[0·34-2·65]
2·19[1·00-3·75]
1·23[0[0[0·46-2·21]
0·68[0·13-1·99] <0.0
ffieied d d plplplaqaque, %%% 52·0 62·0 59·9·7 77 51·2 24·0 <0.0vviaiai tionono s: IQR, intterqrqrquaartrtililileee rarangnge.e.e.
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Table 4A. Carotid plaque composition of asymptomatic patients
Plaque Composition 2002-2003 (n=53)
2004-2005(n=70)
2006-2007(n=49)
2008-2009(n=36)
2010-2011(n=25)
P value
Atheromatous plaque (lipid core > 40% of plaque surface), % 24·5 22·9 26·5 13·9 0·0 <0·001
Plaque thrombosis present % 62·3 75·7 53·1 41·7 16·0 <0·001
Intraplaque vessels (n/hotspot), median [IQR] 7·0[4·2-9·0]
8·7[6·6-12·8]
7·3[4·6-11·0]
6·5[2·6-14·9]
6·0[3·2-12·4] 0·255
Collagen rich plaques % 79·2 90·0 83·7 80·6 84·0 0·968 Median area of macrophages as % of plaque area [IQR]
0·41[0·12-1·22]
0·40[0·05-1·29]
0·91[0·41-1·65]
0·20[0·07-0·49]
0·04[0·00-0·19] 0·003
Median area of smooth muscle as % of plaque area [IQR]
2·96[0·94-5·26]
1·58[0·70-3·12]
2·14[1·09-3·81]
1·39[0·33-2·17]
2·06[0·98-3·68] 0·001
Calcified plaque, % 62·3 70·0 75·5 61·1 24·0 0·011
Table 4B. Carotid plaque composition of patients with ocular symptoms
Plaque Composition 2002-2003 (n=37)
2004-2005(n=51)
2006-2007(n=52)
2008-2009(n=56)
2010-2011(n=56)
P value
Atheromatous plaque (lipid core > 40% of plaque surface), % 21·6 31·4 25·0 19·6 5·4 0·007
Plaque thrombosis present % 83·8 66·7 53·8 44·6 37·5 <0·001
Intraplaque vessels (n/hotspot), median [IQR] 7·0[4·5-10·4]
8·7[5·0-10·7]
7·5[4·1-12·5]
9·0[2·3-13·6]
6·0[2·7-9·1] 0·660
Collagen rich, % 78·4 90·2 84·6 78·6 80·4 0·506 Median area of macrophages as % of plaque area [IQR]
0·49[0·05-1·36]
0·41[0·07-1·22]
0·84[0·39-1·56]
0·32[0·11-0·89]
0·11[0·01-0·44] 0·001
Median area of smooth muscle cells as % of plaque area [IQR]
3·03[0·80-5·98]
1·69[0·60-3·47]
3·05[1·44-4·93]
1·23[0·58-2·41]
0·59[0·07-2·16] <0·001
Calcified plaque, % 59·5 68·6 69·2 44·6 19·6 <0·001
rororomamamatototoususus ppplalalaquququeee (l(l(lipipipididid cccorororeee >> 404040%%% ofofof ppplalalaquququeee ce), %
ueue CComomo pop siititiononon 2200002-2-2 00200303 (n(n(n=3=3=37)7)7)
20202 4404 22-20000555(n(n( =5=5=51)1)1)
2020 6060 22-20000077(n(n=5=5=52)2)2)
[4 2-9 0] [6 6-12 8] [4 6-11 0] [2 6-14 9] [3[3 22-1-12 4]4]gen rich plaques % 79·2 90·0 83·7 80·6 8884·4·4·000 0·0 96an area of macrophages as % of plaque area ]
0·41[0·12-1·22]
0·40[0·05-1·29]
0·91[0·41-1·65]
0·20[0·07-0·49]
0·0·0 040404[0[00·000-0·0 191 ] 0·0·0 00000
an area of smooth muscle as % of plaque area ]
2·96[0·94-5·26]
1·58[0·70-3·12]
2·14[1·09-3·81]
1·39[0·33-2·17]
2·06[0·98-3·68] 0·00
fied d plplplaqaqaqueueue, , , %%% 62·3 70·0 75·5 61·1 24·0 0·01
e e BB4B.. Carotid plaqqueue comomo popositiitionon oof f f papap titienentststs www tith h ocoo ul rrar symyy tpt mmoms
20202 80808-2-200000 99(n(n( 5=5=56)6)6)
02020 010-2- 01010 11(n(nn=5=5=56)6)6)
PP P val
2121 6·6 331·1·4 4 2525·0·0 1919 6·6 55 4·4 00·0·000
ueue tthrhromombobosisiss prpresesenentt %% 8383·8·8 666·6·77 5353·8·8 4444·6·6 337·7·55 <0<0 0·0·0
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Table 4C. Carotid plaque composition of TIA patients
Plaque Composition 2002-2003 (n=100)
2004-2005(n=185)
2006-2007(n=179)
2008-2009(n=148)
2010-2011(n=117)
P value
Atheromatous plaque (lipid core > 40% of plaque surface), % 41·0 36·2 27·4 18·9 19·7 <0·001
Plaque thrombosis present, % 73·0 76·8 65·9 47·3 37·6 <0·001
Intraplaque vessels (n/hotspot), median [IQR] 6·7[4·3-11·0]
8·2[5·7-12·9]
8·0[4·7-12·0]
7·3[4·1-12·4]
6·0[2·3-12·2] 0·212
Collagen rich, % 66·0 84·9 77·1 75·0 77·8 0·664 Median area of macrophages as % of plaque area [IQR]
0·45[0·11-1·28]
0·48[0·09-1·15]
1·15[0·49-2·22]
0·26[0·10-0·62]
0·11[0·01-0·63] <0·001
Median area of smooth muscle cells as % of plaque area [IQR]
1·56[0·39-3·31]
0·89[0·30-2·34]
2·06[0·89-3·48]
1·21[0·47-2·50]
0·57[0·14-1·77] 0·008
Calcified plaque, % 48·0 58·9 53·6 47·3 23·9 <0·001
Table 4D. Carotid plaque composition of stroke patients
Plaque Composition 2002-2003 (n=60)
2004-2005(n=102)
2006-2007(n=72)
2008-2009(n=92)
2010-2011(n=73)
P value
Atheromatous plaque (lipid core > 40% of plaque surface), % 35·0 47·1 26·4 28·3 17·9 0·001
Plaque thrombosis, % 81·7 77·5 66·7 57·6 45·2 <0·001
Intraplaque vessels (n/hotspot), median [IQR] 6·8[5·0-12·4]
8·7[5·0-12·4]
7·3[3·0-11·5]
7·3[3·0-12·0]
6·7[1·7-12·0 0·704
Collagen rich % 78·3 82·4 81·9 77·2 76·7 0·479 Median area of macrophages as % of plaque area [IQR]
0·35[0·04-1·41]
0·44[0·08-1·38]
1·03[0·46-2·33]
0·33[0·10-0·81]
0·09[0·01-0·42] <0·001
Median area of smooth muscle as % of plaque area [IQR]
1·93[0·91-4·10]
0·96[0·21-2·46]
2·07[0·87-3·81]
1·24[0·37-1·97]
0·72[0·08-1·55] <0·001
Calcified plaque % 45·0 58·8 56·9 57·6 27·4 0·031
eueu CCComo positionon 2200 -2-2 002003 (n(n=6== 0)0)0
2022 044-2-2-2000000555(n( =1== 02020 ))
20 6060 22-2007nn(n 7=7=72)2))
2022 80808 22-20009(n(n=9== 2)2)2
0020 010-2- 0100 1
[4 3-11 0] [5 7-12 9] [4 7-12 0] [4 1-12 4] [22 33-1-122 2]2]gen rich, % 66·0 84·9 77·1 75·0 77777 ·8·88 000·66an area of macrophages as % of plaque area ]
0·45[0·11-1·28]
0·48[0·09-1·15]
1·15[0·49-2·22]
0·26[0·10-0·62]
0·0·0 111111[0[00·001-00·636 ] <0<0<0·0·00
an area of smooth muscle cells as % of plaqueIQR]
1·56[0·39-3·31]
0·89[0·30-2·34]
2·06[0·89-3·48]
1·21[0·47-2·50]
0·57[0·14-1·77] 0·00
fied d plplplaqaqaqueueue,,, %%% 48·0 58·9 53·6 47·3 23·9 <0·0
e e DD4D.. Carotid pplaalaququueee cococompmppososositititioioionn ofofo sstrtrtrokokoke e e papap titiienenentststs
(n( =7== 3)3)3P PP val
romamatototoususus ppplalalaquque (l(lipipipididid cccorororee e >>> 404040%% ofof ppplalalaququque eccce)e)e),, %%% 3535·0·0 447·7 11 626·4·4 2828·33 117·99 0·0·000
ue thrombosis, %%% 818181··777 7777·555 6666·6 7 77 575757·6 6 4544 ·2 <0·00066·88 88·77 77·33 77·33 66·77
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Figure Legends:
Figure 1. Semi-quantitative plaque information on intraplaque hemorrhage and luminal
thrombus (A), fat (B), macrophages (C) and calcification (D) based presence and/or degree of
staining.
Figure 2. Adjusted odds ratios for the presence of atherosclerotic plaque characteristics, per 2
year increase from 2002-2011. Odds ratios and p values were adjusted for age, gender, smoking,
total cholesterol, time since last event, index event, statin use, angiotensin II antagonist use, oral
anticoagulant use, clopidogrel use and dipyridamol use. anticoagulant use, clopidogrel use and dipyridamol use.
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Figure 1
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Figure 2
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L. Moll, Michiel L. Bots and Gerard PasterkampVelema, Jean-Paul P. M. de Vries, Dominique P. V. de Kleijn, Aryan Vink, Gert Jan de Borst, Frans
Guus W. van Lammeren, Hester M. den Ruijter, Joyce E. P. Vrijenhoek, Sander van der Laan, EvelynCarotid Surgery
Time Dependent Changes in Atherosclerotic Plaque Composition in Patients Undergoing
Print ISSN: 0009-7322. Online ISSN: 1524-4539 Copyright © 2014 American Heart Association, Inc. All rights reserved.
is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231Circulation published online March 17, 2014;Circulation.
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SUPPLEMENTAL MATERIAL
Supplemental Table 1
Variables used in this study % missingness
Age 0
Gender 0
Smoking 4.9
Diabetes 1.7
Mean arterial pressure 17.5
Total cholesterol 31.5
eGFR 4.3
Body mass index 8.7
Time since last cerebrovascular event 6.6
Index event 0.7
Contralateral stenosis 8.9
History of peripheral artery disease 2.0
History of coronary artery disease 2.0
Statins 3.1
Beta-blockers 3.1
ACE-inhibitors 3.3
Angiotensin II antagonists 3.4
Diuretics 3.1
Aspirin 3.2
Oral anticoagulants 3.1
Supplemental Table 2: Odds ratios between year of inclusion and plaque phenotype after addition of
potential confouders (bold).
Odds ratio (95% CI) between year
of inclusion (per 2 year increase in
time) and
Plaque
thrombosis
Atheromatous
plaque
Calcified
plaque
Univariate 0.64 (0.59-0.69) 0.76 (0.70-0.83) 0.76 (0.71-0.82)
Age 0.63 (0.58-0.69) 0.74 (0.68-0.81) 0.75 (0.69-0.81)
Age, gender 0.63 (0.58-0.69) 0.74 (0.68-0.81) 0.75 (0.69-0.81)
Age, gender, smoking 0.63 (0.58-0.69) 0.74 (0.68-0.81) 0.75 (0.69-0.81)
Age, gender, smoking, total
cholesterol
0.63 (0.58-0.69) 0.74 (0.67-0.81) 0.74 (0.68-0.80)
Age, gender, smoking, total
cholesterol, time since last event
0.63 (0.58-0.69) 0.73(0.67-0.80) 0.74 (0.69-0.80)
Age, gender, smoking, total
cholesterol, time since last event,
index event
0.63 (0.57-0.68) 0.73 (0.66-0.80) 0.74 (0.69-0.80)
Age, gender, smoking, total
cholesterol, time since last event,
index event, statin use
0.63 (0.58-0.68) 0.73 (0.67-0.80) 0.75 (0.69-0.81)
Age, gender, smoking, total
cholesterol, time since last event,
index event, statin use, angiotensin
II antagonist use
0.63 (0.58-0.69) 0.73 (0.67-0.80) 0.75 (0.69-0.81)
Age, gender, smoking, total
cholesterol, time since last event,
index event, statin use, angiotensin II
antagonist use, oral anticoagulant
use
0.63 (0.58-0.69) 0.73 (0.67-0.80) 0.75 (0.69-0.81)
Age, gender, smoking, total
cholesterol, time since last event,
index event, statin use, angiotensin II
antagonist use, oral anticoagulant
use, clopidogrel use
0.63 (0.58-0.69) 0.74 (0.67-0.81) 0.76 (0.70-0.82)
Age, gender, smoking, total
cholesterol, time since last event,
index event, statin use, angiotensin II
antagonist use, oral anticoagulant
use, clopidogrel use, dipyridamol
use
0.63 (0.57-0.69) 0.74 (0.67-0.81) 0.76 (0.70-0.82)
Supplemental Table 3. Subgroup analysis, stratified for statin use, blood pressure medication and
smoking status.
Adjusted odds ratios for the presence of atherosclerotic plaque characteristics, per 2 year increase from 2002-2011. Odds ratios and p
values were adjusted for age, gender, smoking, total cholesterol, time since last event, index event, statin use (expect in the subgroup
analyses), angiotensin II antagonist use, oral anticoagulant use, clopidogrel use and dipyridamol use.
Statin No statin
Plaque thrombosis, OR
(95% CI) 0.65 (0.58-0.72) 0.58 (0.48-0.70)
Atheromatous plaque,
OR (95% CI) 0.77 (0.69-0.86) 0.65 (0.54-0.79)
Calcified plaque
OR (95% CI) 0.75 (0.68-0.82) 0.82 (0.69-0.96)
Blood pressure
medication
No blood pressure medication
Plaque thrombosis,
OR (95% CI) 0.54 (0.44-0.66) 0.65 (0.59-0.72)
Atheromatous plaque,
OR (95% CI) 0.65 (0.51-0.82) 0.76 (0.69-0.85)
Calcified plaque
OR (95% CI) 0.61 (0.50-0.74) 0.81 (0.73-0.89)
Smoker Non-smoker
Plaque thrombosis,
OR (95% CI) 0.64 (0.55-0.74) 0.60 (0.50-0.74)
Atheromatous plaque,
OR (95% CI) 0.78 (0.66-0.92) 0.72 (0.64-0.81)
Calcified plaque
OR (95% CI)
0.76 (0.66-0.87) 0.71 (0.68-0.83)
Supplemental eFigure1.
Panel A and C show raw scatter plots of the % of macrophages and smooth muscle cells in plaques over the years. The % of plaques that fall
into categories of semi-quantitative staining (no, minor, moderate or heavy) are depicted in panel B for collagen and panel D for smooth
muscle cells.
Supplemental eFigure2.
Kaplan Meier survival curves of the patients included in the Athero-Express, stratified by inclusion year.