Article

Effect of Stent Thrombosis on the Risk-Benefit Balance of Drug-Eluting Stents and Bare Metal Stents

Complexo Hospitalario Universitario de A Coruña, Spain.
Revista Espa de Cardiologia (Impact Factor: 3.79). 05/2010; 63(5):528-35. DOI: 10.1016/S1885-5857(10)70114-6
Source: PubMed

ABSTRACT

To determine the difference in the risk of stent thrombosis between drug-eluting stents (DES) and bare-metal stents (BMS) and to assess the clinical implications.
A retrospective analysis of two cohorts of patients treated at our center with either > or =1 paclitaxeleluting stents (PES) (n=430) or > or =1 BMSs (n=1230) during 2003-2004 was carried out using propensity score methods to compare the adjusted risks of stent thrombosis, instent restenosis, cardiovascular death, acute myocardial infarction (AMI), and target-lesion revascularization with the two stent types.
After a median follow-up of 46 months, there was a higher risk of stent thrombosis in PESs (hazard ratio [HR]=3; 95% confidence interval [CI], 1.2-7.1] though the risk of in-stent restenosis was lower (HR=0.3; 95% CI, 0.2-0.7]. There was no difference in the risk of cardiovascular death, AMI or target-lesion revascularization. With PESs, the risks of target-lesion revascularization (HR=0.33; 95% CI, 0.2-0.7) and in-stent restenosis (HR=0.32; 95% CI, 0.2-0.7) were reduced during the first year of follow-up. After this time, the risks of target-lesion revascularization (HR=1.8; 95% CI, 1-3.2) and very late stent thrombosis (HR=12.8; 95% CI, 3-55.1) both increased.
Our findings indicate that the balance of risks and benefits of PESs compared with BMSs is different in the early and late periods after stent implantation. The greatly increased risk of very late stent thrombosis in PESs could cancel out the clinical benefits associated with the reduction in in-stent restenosis observed in PESs relative to BMSs.

Full-text

Available from: Guillermo Aldama, Apr 08, 2014
528 Rev Esp Cardiol. 2010;63(5):528-35
Effect of Stent Thrombosis on the Risk-Benefit Balance
of Drug-Eluting Stents and Bare Metal Stents
Xacobe Flores-Ríos, Juan P. Abugattás-de Torres, Rosa Campo-Pérez, Pablo Piñón-Esteban,
Guillermo Aldama-López, Jorge Salgado-Fernández, Ramón Calviño-Santos, José M. Vázquez-
Rodríguez, Nicolás Vázquez-González and Alfonso Castro-Beiras
Unidad de Hemodinámica, Servicio de Cardiología, Complexo Hospitalario Universitario de A Coruña,
A Coruña, Spain
ORIGINAL ARTICLE
Correspondence: Dr. X. Flores Ríos.
Servicio de Cardiología. Complexo Hospitalario Universitario A Coruña.
As Xubias, s/n. 15006 A Coruña. España.
E-mail: xacobeflores@yahoo.es
Received September 13, 2009.
Accepted for publication December 16, 2009.
Introduction and objectives. To determine the
difference in the risk of stent thrombosis between drug-
eluting stents (DES) and bare-metal stents (BMS) and to
assess the clinical implications.
Methods. A retrospective analysis of two cohorts of
patients treated at our center with either 1 paclitaxel-
eluting stents (PES) (n=430) or 1 BMSs (n=1230) during
2003-2004 was carried out using propensity score methods
to compare the adjusted risks of stent thrombosis, in-
stent restenosis, cardiovascular death, acute myocardial
infarction (AMI), and target-lesion revascularization with
the two stent types.
Results. After a median follow-up of 46 months, there
was a higher risk of stent thrombosis in PESs (hazard ratio
[HR]=3; 95% confidence interval [CI], 1.2-7.1] though the
risk of in-stent restenosis was lower (HR=0.3; 95% CI, 0.2-
0.7]. There was no difference in the risk of cardiovascular
death, AMI or target-lesion revascularization. With PESs,
the risks of target-lesion revascularization (HR=0.33; 95%
CI, 0.2-0.7) and in-stent restenosis (HR=0.32; 95% CI,
0.2-0.7) were reduced during the first year of follow-up.
After this time, the risks of target-lesion revascularization
(HR=1.8; 95% CI, 1-3.2) and very late stent thrombosis
(HR=12.8; 95% CI, 3-55.1) both increased.
Conclusions. Our findings indicate that the balance of
risks and benefits of PESs compared with BMSs is different
in the early and late periods after stent implantation. The
greatly increased risk of very late stent thrombosis in PESs
could cancel out the clinical benefits associated with the
reduction in in-stent restenosis observed in PESs relative
to BMSs.
Key words: Drug-eluting stents. Bare metal stents. Stent
thrombosis.
Influencia de la trombosis del stent
en la relación riesgo-beneficio de los stents
farmacoactivos y los stents convencionales
Introducción y objetivos. Evaluar el riesgo de trom-
bosis del stent (TS) de los stents liberadores de fármaco
(SLF) frente a los stents convencionales (SC) y sus con-
secuencias clínicas.
Métodos. Análisis retrospectivo de dos cohortes de
pacientes tratados con al menos un stent liberador de
paclitaxel (SLP) (n = 430) o uno o más SC (n = 1.268)
en 2003-2004 en nuestro centro mediante métodos de
score de propensión para comparar el riesgo ajustado de
TS, reestenosis del stent (RIS), muerte cardiovascular, in-
farto de miocardio (IAM) y revascularización de la lesión
tratada (RLT) entre ambos dispositivos.
Resultados. Tras una mediana de seguimiento de
46 meses, los SLP presentaron mayor riesgo de TS
(hazard ratio [HR] = 3; intervalo de confianza [IC] del 95%,
1,2-7,1), si bien redujeron el riesgo de RIS (HR = 0,3;
IC del 95%, 0,2-0,7). No hubo diferencias en cuanto a
muerte cardiovascular, IAM o RLT. Los SLP disminuye-
ron el riesgo de RLT (HR = 0,33; IC del 95%, 0,2-0,7) y
RIS (HR = 0,32; IC del 95%, 0,2-0,7) durante el primer
año de seguimiento. Tras este límite, presentaron mayor
riesgo de RLT (HR = 1,8; IC del 95%, 1-3,2) y de TS muy
tardía (HR = 12,8; IC del 95%, 3-55,1).
Conclusiones. Nuestros hallazgos confirman que hay
una relación riesgo-beneficio precoz y tardía diferente
entre el implante de un SLP y el de un SC. El exceso de
riesgo de TS muy tardía puede limitar los beneficios clíni-
cos de los SLP frente a los SC, relacionados con la dis-
minución de la RIS.
Palabras clave: Stents liberadores de fármaco. Stents
convencionales. Trombosis del stent.
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Flores-Ríos X et al. Results of a Cohort of 1698 Patients
Rev Esp Cardiol. 2010;63(5):528-35 529
Revascularization procedures were performed
according to current clinical practice guidelines for
percutaneous coronary interventions (PCI).
10
The
decision to implant a PES was taken by the operator
based on a patient’s individual clinical characteristics.
A loading dose of 300 mg of clopidogrel was
administered to all patients who were not already
taking the drug. Glycoprotein IIb / IIIa inhibitors
were used at the discretion of the operator.
After the intervention, patients received dual
antiplatelet therapy (aspirin and clopidogrel) for
6 months if treated with PES and for 1 month in
those who received BMS. Afterwards, all patients
indefinitely continued monotherapy with aspirin
or clopidogrel. This approach contrasts with
current recommendations on the duration of dual
antiplatelet therapy of 12 months for DES and 1
month for BMS.
11
The hospital supplied sufficient
doses of clopidogrel to ensure compliance with dual
antiplatelet therapy prescribed at discharge.
The primary endpoint was ST. Secondary
endpoints were death from cardiovascular causes,
non-fatal myocardial infarction, clinical restenosis,
and target lesion revascularization.
Medical records and computerized hospital
databases were used to describe the study
population’s baseline characteristics. Major clinical
events after the implant were recorded via telephone
contact and medical charts and through use of
hospital and regional computerized databases. The
regional databases record information from both
primary and specialized healthcare. The relationship
between clinical events and ST was analyzed.
Stent thrombosis was defined according to
the current criteria of the Academic Research
Consortium,
12
and classified as probable or definite.
This classification was applied across the range of
early, late, and very late ST. Stent thrombosis was
defined as probable when there was sudden death
from an unknown cause within 30 days after PCI,
or when myocardial infarction (MI) was observed in
the theoretical area of a previously implanted stent
but it was not possible to confirm the presence of a
thrombus. Thrombosis was considered demonstrated
when stent occlusion by a thrombus was confirmed
by angiography or autopsy. Stent thrombosis were
classified as early if it occurred within the first 30
days after implantation, late if it occurred between
30 and 365 days after implantation, or very late if it
occurred more than one year after implantation.
Acute myocardial infarction (AMI) was defined
as cardiac troponin values greater than the 99th
percentile of reference values with at least one of
the following also present: symptoms consistent
with ischemia, Q waves on the electrocardiogram,
electrocardiographic changes indicating ischemia
(ST-T changes or de novo left bundle branch block),
INTRODUCTION
Compared with bare metal stents (BMS), drug-
eluting stents (DES) reduce the incidence of restenosis
and the subsequent need for new revascularization
procedures.
1,2
On the other hand, DESs increase the
risk of stent thrombosis (ST) compared to BMS,
especially after the first year (very late ST).
3-8
However, the fact that clinical trials are performed
in highly selected patients may mean that their
meta-analysis underestimates the incidence of ST
with DESs. In the real world, where patients with
complex medical conditions (myocardial infarction,
renal failure, ventricular dysfunction) or complex
lesions (bifurcated lesions, restenosis, surgical grafts,
small vessels) are common, the incidence of ST with
DESs should logically be greater.
9
This excess risk of
ST could offset the clinical benefits of DESs implied
by a reduction in restenosis.
In this context, we sought to compare the risk of
ST with DES and BMS and to investigate its possible
clinical consequences in routine clinical practice. We
also specifically aimed to assess the effect of very
late ST on the risk-benefit ratio after implantation
of a DES.
METHODS
Study Design
We performed a retrospective analysis of clinical
outcomes in 2 cohorts composed of all consecutive
patients treated with at least one DES or one BMS
in the study center’s cardiac catheterization lab
during 2003-2004. Patients who received both types
of devices were excluded from the study. During
that time, paclitaxel-eluting stents (PES) were the
only DES available in the study center, so patients
treated with sirolimus-eluting stents or other DES
were not included. Both cohorts of patients were
drawn from the laboratory’s computerized database.
The cardiac catheterization lab database records
the clinical characteristics of patients undergoing
hemodynamic study.
ABBREVIATIONS
AMI: acute myocardial infarction
BMS: bare metal stents
DES: drug-eluting stents
HR: hazard ratio
ISR: in-stent restenosis
ST: stent thrombosis
TLR: target lesion revascularization
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Flores-Ríos X et al. Results of a Cohort of 1698 Patients
lost to follow-up, but no clinical event was registered
for those patients in healthcare databases and,
based on official data, all were alive at the end of
the study.
The baseline characteristics of the 2 groups are
shown in Table 1. Compared with patients who
received BMS, those treated with PES were younger
and more often diabetic. In the PES group, patients
more frequently had a history of prior percutaneous
or surgical revascularization. Multi-vessel disease,
disease of the anterior descending coronary artery
and left main coronary artery, treatment of ISR
or bifurcated lesions were also more frequent
in the PES group. Average stent diameter was
significantly lower in the PES group and covered
stent length was significantly greater. Primary
angioplasty was more frequent in the BMS cohort,
which also had worse left ventricular function than
the PES cohort.
Stent Thrombosis
After a median follow up of 46.1 [interquartile
range, 13] months, the incidence of probable or
definite ST was higher in the PES group than in the
BMS group (3.5% vs 1.3%; P=.003). There were
no differences in the incidence of early (0.5% vs
0.8%; P=.574) or late ST (0.23% vs 0.32%; P=.769).
However, very late ST was more frequent in the
PES group than in the BMS cohort (2.8% vs 0.24%;
P<.001) (Figure, Tables 2 and 3).
After propensity score adjustment, the risk of ST
was higher in PES patients than in the BMS group
(hazard ratio [HR] =3; 95% confidence intervals [CI],
1.2-7.1; P=.014). No differences in risk adjusted ST
were observed during the first year after the index
PCI (HR=0.8; 95% CI, 0.2-3.4; P=.767), while PESs
were associated with an additional risk of very late
ST compared to BMSs (HR=12.8; 95% CI, 3-55.1;
P=.001) (Table 4).
The ST presented as AMI in all cases except 2
(2 sudden deaths in the first 30 days after PCI were
classified as probable ST, with 1 case per group).
Cardiovascular Mortality
There were no differences in cardiovascular
mortality between the PES and BMS groups during
follow-up (5.3% vs 7.3%; P=.26), either during the
first year of follow-up (2.6% vs 2.7%; P=.868) or
after (2.8% vs 4.6%, P=.186) (Table 3).
After propensity score adjustment, there were no
significant differences in the risk of cardiovascular
death between the BMS and PES groups (HR=0.7;
95% CI, 0.4-1.2; P=.195) either during the first
year (HR=1.1; 95% CI, 0.5-2.4; P=.876) or after
(HR=0.6; 95% CI, 0.3-1.2; P=.122) (Table 4).
and imaging evidence of loss of viable myocardium
or impaired segmental contractility.
13
Clinical restenosis was defined as any narrowing
of the stent lumen (including the 5 mm proximal
and 5 mm distal to the stent) observed after clinical
documentation of myocardial ischemia. In the
study center, control coronary angiographies are
not routinely performed after implantation of a
stent.
Statistical Analysis
Continuous variables are reported as means
(standard deviation) and categorical variables as
absolute frequencies (%). The c
2
test or Fisher’s exact
test were used to assess the relationship between 2
categorical variables. Means were compared using
Student t test or the Mann-Whitney test, depending
on the variable’s distribution.
The Kaplan-Meier method was used to analyze
the long-term incidence of the main study endpoints.
The log-rank test was used to compare the time
course of events between the 2 study cohorts.
To compensate for the non-randomized nature of
the study, analyses were carried out after adjusting
by the propensity score,
14
ie, the likelihood that
each individual be treated according to their clinical
characteristics. To calculate each patient’s probability
of receiving a DES, a logistic regression model was
developed in which implantation of a DES was the
dependent variable and independent variables were
age, diabetes mellitus, previous coronary surgery,
renal function, clinical indication, location of injury,
primary angioplasty, in-stent restenosis (ISR),
bifurcated lesions, and stent diameter and length.
The model fit was assessed using the C statistic,
which was 0.8 (95% confidence interval [CI], 0.76-
0.82).
Adjusted odds for each of the study endpoints
were estimated using Cox regression models after
adjusting for the propensity score, which was
introduced as a covariate in each of the models. To
provide separate descriptions of the risk of early
and late clinical events, a landmark analysis was
performed with a 12 month default time limit.
15
Statistical analyses were performed in SPSS
(Statistical Package for Social Sciences) version 17.0
for Windows. A result was considered statistically
significant if P<.05.
RESULTS
A total of 1268 patients were included in the
BMS cohort and 430 in the PES cohort. Follow-up
was completed for 1674 patients or 98% of those
originally included (422 patients in the PES group
and 1252 in the BMS group). Only 24 patients were
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Flores-Ríos X et al. Results of a Cohort of 1698 Patients
Rev Esp Cardiol. 2010;63(5):528-35 531
During follow-up, there were no significant
differences in risk-adjusted non-fatal AMI between
the PES and BMS groups (HR=0.7; 95% CI, 0.4-
1.3; P=.215). When the analysis was performed for
specific time periods, there was no difference during
the first 12 months of follow-up (HR=0.6; 95% CI,
0.3-1.3; P=.16), but beyond 12 months PESs were
associated with a marginally increased risk of AMI
compared to BMSs (HR=2.6; 95% CI, 0.9-7.7;
P=.089) (Table 4).
Non-Fatal Acute Myocardial Infarction
The incidence of AMI was higher in the PES group
than in BMS group, though the difference was not
statistically significant (7.4% vs 4.2%; P=.277). This
event was more frequent in PES patients from the
first year on, although again the difference was not
statistically significant (5.6% vs 1.8%, P=.175). In
the first 12 months there were no differences between
the 2 groups (2.4% vs 1.9%, P=.513) (Table 3).
TABLE 1. Baseline characteristics
BMS (n=1268) PES (n=430) P
Cardiovascular risk factors
Age, mean (SD), y 64.6 (11.5) 61.6 (11.6) <.001
Men 1.021 (80.5) 360 (83.7) .138
Smoking 374 (29.5) 124 (28.8) .796
Hypertension 687 (54.2) 227 (52.8) .607
Diabetes mellitus 278 (21.9) 119 (27.7) .016
Dyslipidemia 817 (64.4) 282 (65.6) .694
Cardiac history
AMI 300 (23.7) 90 (20.9) .239
CABG 38 (3) 32 (7.4) <.001
PCI 121 (9.5) 71 (16.5) <.001
Clinical situation
Unstable angina 464 (36.6) 181 (42.1) .042
AMINSTE 229 (18.1) 86 (20) .371
AMIWSTE 392 (30.9) 82 (19.1) <.001
LVEF
a
59.7 (13.8) 61.6 (12.2) .02
Co-morbidities
Kidney failure
b
256 (20.2) 70 (16.3) .075
CrCI, mL/min
c
79.69 (32.82) 81.96 (30.49) .209
Cerebrovascular disease 63 (5) 22 (5.1) .911
Peripheral arterial disease 112 (8.8) 42 (9.8) .569
COPD 60 (4.7) 17 (4) .503
Angiographic data
No of diseased vessels 1.66 (0.75) 1.7 (0.75) .068
Multi-vessel disease 622 (49.1) 240 (55.8) .015
Number of stents 1.72 (0.96) 1.73 (0.98) .766
Location of lesion
Anterior descending 598 (47.2) 295 (68.6) <.001
Circumflex 405 (31.9) 112 (26) .021
Right coronary artery 569 (44.9) 134 (31.2) <.001
Coronary trunk 13 (1) 25 (5.8) <.001
Arterial or venous bypass 15 (1.2) 9 (2.1) .167
Bifurcated lesion 178 (14) 93 (21.6) <.001
Stent restenosis 31 (2.4) 41 (9.5) <.001
Primary angioplasty 272 (21.5) 35 (8.1) <.001
Stent diameter, mm 3.16 (1) 3 (0.37) <.001
Stent length, mm 31.02 (18.88) 36.4 (22.83) <.001
AMI indicates acute myocardial infarction; AMINSTE, AMI without ST elevation; AMIWSTE, AMI with ST elevation; BMS, bare metal stents; CABG, coronary artery bypass graft;
LVEF, left ventricular ejection fraction; PCI, percutaneous coronary intervention; PES, paclitaxel-eluting stent.
a
LVEF was estimated using echocardiography or ventriculography.
b
Renal failure is defined as a creatinine clearance of <50 mL/min.
c
Creatinine clearance was estimated using the Cockroft-Gault formula. Data are expressed as n (%) or means (standard deviation).
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Flores-Ríos X et al. Results of a Cohort of 1698 Patients
Stent Restenosis
Stent restenosis was less frequent in the PES
group (cumulative incidence of 2.8% vs 5.4% in the
BMS group; P=.025). This difference was primarily
seen during the first year of follow-up (2.1% vs 4.1%;
P=.05), with no statistically significant differences
observed beyond that point (0.7% vs 1.3%; P=.291)
(Table 3).
The use of PES reduced the risk-adjusted likelihood
of restenosis compared to BMS (HR=0.3; 95% CI,
0.2-0.7; P=.001), particularly in the first 12 months
(HR=0.32; 95% CI, 0.2-0.7; P=.003). Beyond that
point, the difference was not statistically significant
(HR=0.4; 95% CI, 0.1-1.6; P=.206) (Table 4).
Target-Lesion Revascularization
There were no statistically significant differences
in the incidence of target lesion revascularization
01224
0.05
0.04
0.03
0.02
0.01
0
Incidence of stent thrombosis, %
Duration of follow-up, mo
P=0.003
36
48 60
BMS
PES
Figure 1. Incidence of stent thrombosis
in paclitaxel-eluting stents (PES) and bare
metal stents (BMS).
TABLE 2. Incidence of Early, Late, and Very Late Stent
Thrombosis in Bare Metal and Paclitaxel-Eluting
Stents
BMS (n=1268) PES (n=430) P
a
Early ST
Definite 8 (0.63) 0 .097
Probable 2 (0.16) 2 (0.46) .102
Total 10 (0.79) 2 (0.46) .574
Late ST
Definite 4 (0.32) 1 (0.23) .769
Probable 0 0
Total 4 (0.32) 1 (0.23) .769
Very late ST
Definite 2 (0.16) 11 (2.55) <.001
Probable 1 (0.08) 1 (0.23) .288
Total 3 (0.24) 12 (2.8) <.001
ST total 17 (1.3) 15 (3.5) .003
BMS indicates bare metal stent; PES, paclitaxel-eluting stent; ST, stent thrombosis.
a
Log-rank test.
Data express n (%) of events.
TABLE 3. Incidence of Clinical Events With Bare Metal and Paclitaxel-Eluting Stents
Event
Total First Year After First Year
C PES P
a
BMS PES P
a
BMS PES P
a
Cardiovascular death 92 (7.3) 23 (5.3) .26 34 (2.7) 11 (2.6) .868 58 (4.6) 12 (2.8) .186
Non-fatal AMI 53 (4.2) 32 (7.4) .277 30 (2.4) 8 (1.9) .513 23 (1.8) 24 (5.6) .175
ST total 17 (1.3) 15 (3.5) .003 14 (1.1) 3 (0.7) .529 3 (0.24) 12 (2.8) <.001
In-stent restenosis 69 (5.4) 12 (2.8) .025 52 (4.1) 9 (2.1) .05 17 (1.3) 3 (0.7) .291
TLR 82 (6.5) 22 (5.1) .282 63 (5) 10 (2.3) .017 19 (1.5) 12 (2.8) .084
AMI indicates acute myocardial infarction; BMS, bare metal stent; PES, paclitaxel-eluting stent; ST, stent thrombosis; TLR, target-lesion revascularization.
a
Log-rank test.
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Flores-Ríos X et al. Results of a Cohort of 1698 Patients
Rev Esp Cardiol. 2010;63(5):528-35 533
the PES group were very late ST (12 [80%] of 15
cases); these events would not have been recorded in
studies with shorter follow-up periods. On the other
hand, the incidence of ST with PES in our study was
consistent with rates reported by other, more recent
studies with similar follow-up periods.
22
Our study supports the existence of a risk-benefit
ratio for PES which varies over time, and which
differs from BMS in terms of the incidence of early
and late ST.
The use of PES did not significantly reduce the need
for new revascularization procedures compared with
BMS. However, during the first year of monitoring,
PES markedly reduced the need for TLR, and reduced
the risk of ISR. However, thereafter, the use of SLP
was associated with a 13 times greater risk of ST,
which resulted in an increased risk of TLR compared
with BMS. Similarly, there was no difference in the
rate of revascularization of the treated vessel (TVR)
at 3 years between DESs and BMSs in the BASKET
LATE study (TVR rate of 14.7% for DES compared
to 17.5% for BMS; P=.29), a fact which the authors
linked to ST.
23
In randomized studies, DESs reduced
the need for new revascularization procedures
compared with BMS.
1,2
These studies underestimate
the incidence of late and very late ST because they
systematically exclude clinically complex patients;
this in turn may mean they overestimated the
benefit of DESs by minimizing the impact of late
ST. Other observational studies have also shown a
decrease in the need for further revascularization
with DES compared to BMS, but they also tend to
underestimate the volume of ST in DES because of
the use of short follow-up periods.
24-26
The role of ISR in the absence of statistically
significant differences in terms of TLR between the
PES and BMS groups deserves comment. We found
the risk of ISR to be markedly reduced with PES,
a finding which conforms with the large body of
evidence available today. However, the low rate of
ISR (5.8%) after implantation of a BMS is striking,
and we found little difference in absolute values as
regards the need for TLR in BMS and PES patients
(TLR) between the PES and BMS groups (5.1% vs
6.5%; P=.282). In the first year, the incidence of TLR
was lower in the PES group (2.3% vs. 5%; P=.017);
from that point on, a higher incidence of TLR was
observed in the PES group, with the difference
approaching statistical significance (2.8% vs 1.5%;
P=.084) (Table 3).
There were no differences in risk-adjusted TLR
between the 2 devices (HR=0.8; 95% CI, 0.5-1.3;
P=.355). However, the risk of TLR in the first year
was significantly lower in the PES group (HR=0.33;
95% CI, 0.2-0.7; P=.002). After 12 months, PES
showed an excess risk of TLR compared with BMS
(HR=1.8; 95% CI, 1-3.2; P=.05) (Table 4).
DISCUSSION
Late thrombosis is the main concern with
PESs.
16,17
The main finding of this study was that an
excess risk of ST with PES compared to BMS could
limit the clinical benefits obtained by a lower risk of
restenosis with DESs. The risk of ST with PESs was
greater in absolute terms in this real-life scenario
than in experimental situations.
In this study, PES was associated with an excess
risk for ST compared to BMS, due to very late ST.
The incidence of ST with PES in this series (3.5%) was
higher than that reported in several meta-analyses.
3-8
This is probably due to the more complex clinical
situation of the patients in our sample. In fact, this
factor has been identified as a serious drawback
of meta-analyses in quantifying the impact of late
ST with DESs.
9
Other observational studies have
reported varying figures, but they have generally
been significantly lower than those reported here
(generally <1%).
18,19
On the other hand, they have
usually used shorter follow-up periods (<2 years).
As DES are consistently associated with late ST,
20,
21
the duration of our follow-up likely explains the
difference between our findings and those of previous
studies. Cumulative incidence at 1 year in our PES
group (0.5%) was in fact similar to that reported
in previous studies. In addition, most of the ST in
TABLE 4. Adjusted Risk of Clinical Events in Paclitaxel-Eluting Stents Compared to Bare Metal Stents
Event
Total First Year After First Year
HR (95% CI) P HR (95% CI) P HR (95% CI) P
Cardiovascular death 0.7 (0.4-1.2) .195 1.1 (0.5-2.4) .876 0.6 (0.3-1.2) .122
Non-fatal AMI 0.7 (0.4-1.3) .215 0.6 (0.3-1.3) .16 2.6 (0.9-7.7) .089
Total ST 3 (1.2-7.1) .014 0.8 (0.2-3.4) .767 12.8 (3-55.1) .001
In-stent restenosis 0.3 (0.2-0.7) .001 0.32 (0.2-0.7) .003 0.4 (0.1-1.6) .206
TLR 0.8 (0.5-1.3) .355 0.33 (0.2-0.7) .002 1.8 (1.0-3.2) .051
AMI indicates acute myocardial infarction; HR, hazard ratio; ST, stent thrombosis; TLR, target-lesion revascularization; stent.
Page 6
534 Rev Esp Cardiol. 2010;63(5):528-35
Flores-Ríos X et al. Results of a Cohort of 1698 Patients
Study Limitations
This study may have several limitations. Data
were collected from a registry in a single institution
so the study may not be free of the biases inherent
to this type of design. Patient follow-up was not
complete. Patients who are lost to follow-up tend to
have a greater number of events, which could modify
the study results. Our results should be interpreted
with caution, as confounding variables may have
contributed to differences after adjustment. Since
we included only patients with PES, these results
may not be applicable to other types of DES. In fact,
PESs appear to entail greater risk of ST than other
DES.
27
A further limitation was that compliance
with dual antiplatelet therapy was not monitored
during follow-up. Finally, these findings derive from
usual practice in our cardiac catheterization lab and
might not be reproducible in labs with a different
policy of DES implantation.
CONCLUSIONS
Under clinical practice conditions at the study
center, PESs were associated with increased adjusted
risk of ST compared to BMSs. The difference was
primarily due to excess risk of very late ST with
PESs. Our findings indicate the existence of a
differential risk-benefit ratio in the early and late
stages after implantation of a PES. With PESs, the
initial benefit obtained from a reduction of ISR and
of the need for further revascularization is offset
by the excess risk of very late ST. When compared
to BMS, very late ST in DESs appears to limit
the clinical benefits achieved through a reduction
in new revascularization procedures related to a
decline in ISR. The results should be interpreted
with caution due to the non-randomized nature of
the study. Confounding factors may also contribute
to differences after adjustment. Further studies are
required into the evolution of very late ST and its
clinical consequences.
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  • [Show abstract] [Hide abstract] ABSTRACT: "Necessity, who is the mother of invention." - Plato. There has been a steady rise in the incidence and prevalence of coronary artery disease. In most developed countries, it is the number one cause of morbidity and mortality. As this disease has become an ever increasing burden on society, it has spurred on the development of many radical and innovative procedures and implants. This paper will discuss, briefly, the history of coronary interventions ranging from coronary artery bypass grafts (CABG) to drug-eluting stents. It will then compare and contrast some of the several drug-eluting stents available on the market today; specifically focusing on the CypherTM, TaxusTM, EndeavourTM, and Xience VTM stents. The comparisons will include a basic overview of the specifications of each stent as well as the short- and long-term outcomes of these implants. Finally, the paper will provide an introduction to some of the latest stent technology awaiting FDA approval.
    No preview · Article · Jan 2011 · Journal of Long-Term Effects of Medical Implants
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Background: The Taxcor PL registry was a multicentre, phase IV open clinical trial, in which there participated 10 academic centres in Poland. Its aim was to assess the safety and effectiveness of the stent Genius TAXCOR I (Eurocor GmbH, Germany) at a dose of 1 μg/mm2 of paclitaxel, implanted during PCI with elective or urgent indications. Material and methods: Patients who entered the study were a group of patients qualified for PCI, based on clinical symptoms and provocative tests, in whom coronary angiography confirmed the presence of significant stenosis (length up to 25 mm) in the coronary arteries. Implantation procedure, peri- and postoperative procedure were in accordance with guidelines and local practice. The study protocol did not interfere with standard treatment for patients with a diagnosis of ischaemic heart disease. The total number of patients studied in the Taxcor PL registry is 100 people recruited in 10 centres in Poland. Results: Data were collected during the study on 100 PCIs (110 treated lesions). Average duration of PCI was 43 min (SD 24). Mean diameter of the implanted stent was 3.17 mm (SD 0.36) and the average length of 20.5 mm (SD 5.82). The mean time of hospitalization of patients enrolled in the study was 2.5 days (SD 3.4). During hospitalization, 2 patients experienced myocardial infarction which was the result of side branch closure during PCI. Three patients had a haematoma at the puncture site, which did not require surgical intervention and transfusion of blood products. During percutaneous coronary intervention also three cases of distal dissection were reported (type B, C and D). There were no other adverse events. In one-month follow-up one of the patients had a planned PCI procedure performed in another vessel than previously treated, which was the next stage of coronary revascularization. Similarly, in the 3-month follow-up one of the patients needed to undergo a PCI procedure on a vessel untreated with Taxcor. In the 6-month follow-up (3-6 months) one patient died - he was hospitalized with a diagnosis of malignant tumour and the gastrointestinal tract and operated on at the surgical ward (hemicolectomy); after 2 months of hospitalization, he died due to multiorgan failure. Five patients had a second percutaneous coronary intervention in other vessels than at the time of study enrolment. At 12-month follow-up (6-12 months) two patients had a second PCI procedure performed, including one in a vessel treated at the time of enrolment. Ineffectiveness of supply target vessel (called target vessel failure, TVF) occurred in three patients (death from coronary causes - 0, MI - 2, target vessel revascularization (TVR - PCI or CABG) during the 12-month observation period - 1. Conclusions: Taxcor PL registry results showed that the stent Genius Taxcor I is safe to use and provides satisfactory results in short- and long-term observation, in comparison with other commercially available coronary stent systems.
    Full-text · Article · Oct 2011 · Postepy w Kardiologii Interwencyjnej / Advances in Interventional Cardiology
  • [Show abstract] [Hide abstract] ABSTRACT: Aims: Randomized clinical trials (RCTs) are the most reliable evidence, even if they require important resource and logistic efforts. Large, cost-free and real-world datasets may be easily accessed yielding to observational studies, but such analyses often lead to problematic results in the absence of careful methods, especially from a statistic point of view. We aimed to appraise the performance of current multivariable approaches in the estimation of causal treatment and effects in studies focusing on drug-eluting stents (DES). Methods and Results: Pertinent studies published in the literature were searched, selected, abstracted, and appraised for quality and validity features. Six studies with a logistic regression were included, all of them reporting more than 10 events for covariates and different length of follow-up, with an overall low risk of bias. Most of the 15 studies with a Cox proportional hazard analysis had a different follow-up, with less than 10 events for covariates, yielding an overall low or moderate risk of bias. Sixteen studies with propensity score were included: the most frequent method for variable selection was logistic regression, with underlying differences in follow-up and less than 10 events for covariate in most of them. Most frequently, calibration appraisal was not reported in the studies, on the contrary of discrimination appraisal, which was more frequently performed. In seventeen studies with propensity and matching, the latter was most commonly performed with a nearest neighbor-matching algorithm yet without appraisal in most of the studies of calibration or discrimination. Balance was evaluated in 46% of the studies, being obtained for all variables in 48% of them. Conclusions: Better exploitation and methodological appraisal of multivariable analysis is needed to improve the clinical and research impact and reliability of nonrandomized studies. (J Interven Cardiol 2012;25:611–621)
    No preview · Article · Aug 2012 · Journal of Interventional Cardiology
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