European Heart Journal Supplements (2015) 17 (Supplement B), B57–B64
The Heart of the Matter
doi:10.1093/eurheartj/suv022
Clinical outcomes and risk factors of periprocedural
myocardial injury after successful percutaneous
coronary intervention for chronic total occlusions
Xin Zhong1†, Hua Li1,2†, Hongbo Yang1†, Kang Yao1, Xuebo Liu1,3, Kai Hu1,4,
Juying Qian1, Lei Ge1, and Junbo Ge1,5*
1
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, 180 Fenglin Road,
Shanghai 200032, China
2
Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy
of Sciences, Shanghai 200031, China
3
Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
4
Department of Internal Medicine I, Comprehensive Heart Failure Center, University of Würzburg,
Würzburg D-97080, Germany
5
Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
KEYWORDS
Chronic total coronary
occlusion;
Periprocedural myocardial
injury;
The parallel wire technique;
The retrograde wire
technique;
Major adverse cardiac events
†
Limited published data about periprocedural myocardial injury (PMI) after successful
chronic total occlusion (CTO)-percutaneous coronary intervention (PCI) were available.
The study aimed to investigate risk predictors and clinical implications of PMI after successful CTO-PCI and drug-eluting stent (DES) implantation. Between 2009and 2012, a
total of 437 patients who underwent successful recanalization with DESs were included.
All the cardiac troponin T (cTnT)-positive patients were excluded. As the benchmark in
PMI defined as cTnT .5 × the 99th percentile ULN, the independent predictors and
major adverse cardiac events (MACEs) involving cardiac death, myocardial infarction,
and target-vessel revascularization were compared between the PMI group and the no
PMI group. The incidence rate of PMI was 18.3% (80/437) after the index procedure. Multivariate analysis showed that calcification (OR: 2.203, confidence interval [CI] 1.262–
3.845, P ¼ 0.005), the parallel wire technique (OR: 3.178, CI 1.661–6.081, P , 0.001),
and the retrograde wire technique (OR: 5.554, CI 2.275–13.558, P , 0.001) were independent predictors of PMI after successful CTO-PCI and DES implantation. Major
adverse cardiac events were significantly higher in the PMI group (adjusted hazard
ratio 3.704; 95% CI 1.759–7.796; P ¼ 0.001) during the 3-year follow-up. The independent predictors of PMI after successful recanalization with DESs are calcification, the parallel wire technique, and the retrograde wire technique. Periprocedural myocardial
injury after the index procedure is associated with more adverse clinical events.
Further large clinical studies combined with bioinformatics are warranted to explore
the implications of patients with this distinct new entity.
X.Z., H.L., and H.Y. contributed equally to this work.
* Corresponding author. Tel: +86 21 64041990 2745, Fax: +86 21 64223006,
Email: [email protected]
Introduction
Periprocedural myocardial injury (PMI) is relatively common
after percutaneous coronary interventions (PCIs),1–5 and has
Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2015.
For permissions please email: [email protected]
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been proved to predispose worse prognosis,6–8 which was
defined as a troponin elevation of .5 the upper limit of
normal (ULN), an update of cut-off point, referring to the
third universal definition of PMI (type 4a).9 However, the
prognostic value of PMI assessed by different biomarkers
and threshold is still a matter of debate.10,11
In spite of the remarkable progress in the technologies
and techniques achieved in the PCI for chronic total occlusions (CTOs) over the last decade and the rate of procedural
success being up to 80–90% in some centres across the
world, recanalization for CTOs of native coronary arteries
remains challenging, and is still regarded as the ‘last frontier’ of PCI.12 In addition, various iatrogenic injuries during
PCI such as dissection,13 side-branch occlusion14
, and distal
embolization15 were reported to be associated with PMI,
thereby yielding better clinical outcomes with decreased
complications through the successful recanalization of
CTOs could be expected.
Up to now, with various case reports focusing on CTO-PCI
and drug-eluting stent (DES) implantation published in journals, safety concerns have been gradually raised. However,
only one retrospective study is available regarding the clinical outcome of PMI after successful CTO-PCI,16 which needs
to be prudently evaluated through analysis of additional
study with a larger population. Therefore, we designed
the current study to investigate the incidence, independent
predictors, and clinical outcomes of PMI for patients undergoing successful CTO interventions with DES implantation.
Methods
Study population
From May 2009 to December 2012, a total of 437 cardiac troponin
T (cTnT)-negative patients with successful recanalization of
CTOs in the native coronary arteries at the Shanghai Institute of
Cardiovascular Diseases, Zhongshan Hospital of Fudan University
and Chronic Total Occlusion Club, China (CTOCC), were consecutively included in the study. The procedural success rate of
CTO-PCI was 81.4% for the same period. Patients enrolled in the
current study were divided into the PMI group and the no PMI
group according to the presence of PMI after successful CTO-PCI
with DES implantation.
All the percutaneous revascularizations of CTOs were performed
according to the current standard guidelines. All patients without
contraindication received a loading dose of 300 mg aspirin (97.3%)
and clopidogrel (100%). After operation, patients were advised to
maintain their lifelong aspirin therapy, and at least a 12-month clopidogrel prescription. Blood samples were drawn from all patients
before PCI and at 24 h after intervention for measurement of cTnT
concentrations.
Each CTO-PCI was performed by at least two different operators
from our centre or CTOCC. All of the operators achieved .300 PCIs
per year. The study protocol was approved by the hospital’s
medical ethics committee. All patients provided written informed
consent before participating in the procedure.
Definitions
Chronic total occlusion is defined as thrombolysis in myocardial infarction (TIMI) grade 0 flow and the duration of coronary occlusion
is ≥3 months.12 In the absence of serial angiograms, the duration of
X. Zhong et al.
coronary occlusion is instead estimated from available clinical
information related to the event that caused the occlusion (e.g.
acute MI or sudden change in angina pattern with ECG changes consistent with the location of the occlusion).12 Angiographic success
was defined as a restoration of TIMI flow grade 3 in the target vessel
after DES implantation and a residual stenosis of ,10% by visual
estimation.
Periprocedural myocardial injury is defined by the elevation of
cTnT values (.5 × 99th percentile ULN).9 The angiographic
indices examined were the locations of the CTO, PMI, diffuse
disease proximal to the occlusion (at least one stenosis of .50%
proximal to the occlusion),17 side branch at the occlusion, vessel
tortuosity (the presence of at least one bend of .458 proximal to
the occlusion),17 calcification at the site of the occlusion (radioopacity present before contrast injection), ostial occlusion (occlusion within 3 mm of the ostial), stump morphology (a blunt or
tail-like stump), and grades of bridging collaterals (0 ¼ none;
1 ¼ filling of side branches of the artery to be dilated via collateral
channels without visualization of the epicardial segment; 2 ¼
partial filling of the epicardial segment via collateral channels;
3 ¼ complete filling of the epicardial segment of the artery being
dilated via collateral channels).18 Angiographic restenosis was
defined as a ≥50% diameter stenosis within the target lesion.
All of the films were reviewed by at least two qualified interventional doctors. If there was any ambiguity in the reports or films,
the films were reviewed independently by the third well-qualified
interventional doctor.
Study endpoints
The clinical follow-up duration of patients in both groups was
defined as the time from the first successful CTO-PCI to 31 December 2013. The major adverse cardiac events (MACEs), including
cardiac death, myocardial infarction (MI), target-vessel revascularization (TVR), were recorded. Myocardial infarction was
defined as the elevation of the cardiac troponin with at least one
value above the 99th percentile of the ULN and with at least one
of the following: (i) symptoms of ischaemia, (ii) new or presumably
new significant ST-segment–T wave (ST–T) changes or new left
bundle branch block, (iii) development of pathological Q waves
in the ECG, (iv) imaging evidence of new loss of viable myocardium,
or new regional wall motion abnormality, and (v) identification of
an intracoronary thrombus by angiography or autopsy.9 Targetvessel revascularization was defined as emergency or elective coronary artery bypass graft or repeat PCI in the target vessel.
Statistical analysis
The data were expressed as the mean + SD for the continuous
variables, and as frequencies for the categorical variables. The
comparison of continuous variables was performed by the independent Student’s t-test or the Mann–Whitney U-test as appropriate. Statistical analysis of the categorical variables was performed
using the Pearson x 2 or Fisher’s exact test as appropriate. The
multivariate logistic regression model (all variables found to
have univariate association with PMI after CTO-PCI and P , 0.1
were included into the analysis) was used to identify the independent predictors of PMI after successful CTO-PCI and DES implantation. Cumulative incidence was estimated by the Kaplan–Meier
method, and differences were assessed with the log-rank test.
We used Cox proportional hazard models to estimate the risk of
the PMI for clinical outcomes adjusting for the differences in
patient baseline, angiographic, and procedural factors. P-values
were two-tailed, and a value of P , 0.05 was considered statistically significant. The data were analysed with the SPSS v.20.0 statistical software (SPSS, version 20.0, Inc., Chicago, IL, USA).
Mid-term follow-up of PMI after CTO-PCI
B59
Results
Between May 2009 and December 2012, a total of 437
patients with successful recanalization of CTOs were analysed in the study. Periprocedural myocardial injury was
observed in 18.3% (80/437) of the enrolled population.
Aspirin was applied after discharge for 97.5% (78/80) of
patients with PMIs and 97.2% (347/357) of patients
without PMIs. Clopidogrel (at least a 12-month administration) was definitely applied after discharge to all the
patients included in the current study. The main reason
for discontinuing aspirin was gastrointestinal side-effect
or bleeding.
Baseline clinical characteristics
The baseline clinical characteristics of the patients are presented in Table 1. The mean age of our cohort was 62.19 +
11.12 years. As is common in CTO-PCI series, male was the
dominant group in the overall patients. The prevalence of
current smokers was 27.5%, and history of hypertension
and MI was 65.2 and 29.7%, respectively. A significant difference in the age (64.76 + 11.03 vs. 61.61 + 11.08
years, P ¼ 0.022) was shown between the PMI group and
the no PMI group, whereas there were no significant differences among the other baseline clinical characteristics
between the two groups.
Angiographic and procedural characteristics
Table 2 summarizes the angiographic characteristics of all
the lesions. About 54.2% occurred with triple-vessel disease.
Left anterior descending artery was the most common site
of CTO in this study (202/437, 46.2%). Most of CTO’s morphological characteristics, which were acknowledged to be associated with procedural success, showed no significant
difference between the two groups. In particular, calcification (45.0 vs. 25.8%, P ¼ 0.001) was the only risk factor associated with PMI after successful CTO-PCI with DESs.
Procedural characteristics
The procedural characteristics including devices and techniques are given in Table 3. Multivessel intervention with
CTO-PCI accounted for 23.8% (104/437) of the overall
lesions. The parallel wire technique and the retrograde
wire technique were used in 12.8% (56/437) and 6.2%
(27/437) of all the lesions, respectively. The Seesaw technique (3/437, 0.7%) and the side-branch technique
(11/437, 2.5%) were rarely used in the lesions including in
the current study. The average stent length is 61.59 +
26.71 mm. Compared with other procedural factors, the
parallel wire technique (26.3 vs. 9.8%, P , 0.001) and the
retrograde wire technique (16.3 vs. 3.9%, P , 0.001)
were associated with more PMI after successful CTO-PCI
with DESs.
Multiple logistic regression analysis
The multiple logistic regression analysis (Table 4) revealed
that calcification (OR: 2.203, confidence interval [CI]
1.262–3.845, P ¼ 0.005), the parallel wire technique
(OR: 3.178, CI 1.661–6.081, P , 0.001), and the retrograde
wire technique (OR: 5.554, CI 2.275–13.558, P , 0.001)
Table 1 Baseline clinical characteristics
Clinical characteristics
Overall (n ¼ 437)
With PMI (n ¼ 80)
Without PMI (n ¼ 357)
Gender, male
Age, years
Age ≥75
Clinical presentation
Asymptoms
Stable angina
Unstable angina
Smoking status
Never
Former
Current
Hypertension
Diabetes
Prior MI
Medications
Aspirin
Clopidogrel
b-Blockers
ACEI/ARB
Statin
Post-PCI cTnT, ng/mL
360 (82.4)
62.19 + 11.12
63 (14.4)
63 (78.8)
64.76 + 11.03
18 (22.5)
297 (83.2)
61.61 + 11.08
45 (12.6)
0.346
0.022
0.023
7 (1.6)
223 (51.0)
207 (47.4)
3 (3.8)
37 (46.3)
40 (50.0)
4 (1.1)
186 (52.1)
167 (46.8)
0.182
239 (54.7)
78 (17.8)
120 (27.5)
285 (65.2)
139 (31.8)
130 (29.7)
47 (58.8)
15 (18.8)
18 (22.5)
58 (72.5)
29 (36.3)
21 (26.3)
192 (53.8)
63 (17.6)
102 (28.6)
227 (63.6)
110 (30.8)
109 (30.5)
0.544
425 (97.3)
437 (100)
396 (90.6)
357 (81.7)
430 (98.4)
0.11 + 0.20
78 (97.5)
80 (100)
71 (88.8)
64 (80.0)
77 (96.3)
0.40 + 0.33
347 (97.2)
357 (100)
325 (91.0)
293 (82.1)
353 (98.9)
0.04 + 0.04
P-value
0.130
0.345
0.449
1.000
1.000
0.526
0.665
0.119
,0.001
Data are presented as mean + SD or n (%).
PMI, periprocedural myocardial injury; MI, myocardial infarction; ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker;
cTnT, cardiac troponin T.
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X. Zhong et al.
Table 2 Angiographic characteristics
Number of vessels diseased
Single
Double
Triple
Location of CTO
LM
LAD
LCX
RCA
Previously failed lesion
Diffuse disease proximal to occlusion
Side branch at occlusion
Vessel tortuosity
Calcification
Ostial occlusion
Stump
No stump
Blunt stump
Tail-like stump
Collateral circulation (grade)
1
2
3
Overall (n ¼ 437)
With PMI (n ¼ 80)
Without PMI (n ¼ 357)
P-value
72 (16.5)
128 (29.3)
237 (54.2)
13 (16.3)
21 (26.3)
46 (57.5)
59 (16.5)
107 (30.0)
191 (53.5)
0.777
1 (0.2)
202 (46.2)
58 (13.3)
176 (40.3)
45 (10.3)
134 (30.7)
87 (19.9)
89 (20.4)
128 (29.3)
40 (9.2)
0 (0)
34 (42.5)
8 (10.0)
38 (47.5)
11 (13.8)
29 (36.3)
19 (23.8)
21 (26.3)
36 (45.0)
8 (10.0)
1 (0.3)
168 (47.1)
50 (14.0)
138 (38.7)
34 (9.5)
105 (29.4)
68 (19.0)
68 (19.0)
92 (25.8)
32 (9.0)
0.461
46 (10.5)
126 (28.8)
265 (60.6)
12 (15.0)
27 (33.8)
41 (51.3)
34 (9.5)
99 (27.7)
224 (62.7)
0.128
10 (2.3)
82 (18.8)
345 (78.9)
1 (1.3)
11 (13.8)
68 (85.0)
9 (2.5)
71 (19.9)
277 (77.6)
0.328
0.261
0.231
0.341
0.148
0.001
0.771
Data are presented as mean + SD or n (%).
PMI, periprocedural myocardial injury; CTO, chronic total occlusion; LM, left main; LAD, left anterior descending artery; LCX, left circumflex artery;
RCA, right coronary artery.
Table 3 PCI procedural characteristics
Multivessel intervention with CTO-PCI
Use of microcatheter
Use of IVUS
Contralateral injection
Guidewire technique
Parallel wire technique
Seesaw technique
Side-branch technique
Retrograde wire technique
Total stent length, mm
Procedural complication
Pseudoaneurysm
New-onset pericardial effusion
Cardiac tamponade
Overall (n ¼ 437)
With PMI (n ¼ 80)
Without PMI (n ¼ 357)
104 (23.8)
252 (57.7)
15 (3.4)
148 (33.9)
24 (30.0)
47 (58.8)
5 (6.3)
33 (41.3)
80 (22.4)
205 (57.4)
10 (2.8)
115 (32.2)
56 (12.8)
3 (0.7)
11 (2.5)
27 (6.2)
61.59 + 26.71
21 (26.3)
0 (0)
2 (2.5)
13 (16.3)
66.89 + 25.42
35 (9.8)
3 (0.8)
9 (2.5)
14 (3.9)
60.41 + 26.89
6 (1.4)
7 (1.6)
4 (0.9)
0 (0)
3 (3.8)
2 (2.5)
6 (1.7)
4 (1.1)
2 (0.6)
P-value
0.150
0.828
0.165
0.123
,0.001
1.000
1.000
,0.001
0.050
0.598
0.119
0.155
Data are presented as mean + SD or n (%).
PCI, percutaneous coronary intervention; PMI, periprocedural myocardial injury; IVUS, intravascular ultrasound; CTO, chronic total occlusion.
were the independent predictors of the occurrence of PMI
after successful CTO-PCI with DES implantation.
Outcomes
During the mid-term follow-up (median duration: 763 days;
interquartile range: 446–1135 days), 404 patients (92.4%)
completed follow-up. Kaplan–Meier estimates of the
MACEs in the two study groups are shown in Figure 1. During
3-year follow-up, 17.5% of patients in the PMI group and 6.4%
of patients in the no PMI group experienced MACEs
(Figure 1A). The event rates for cardiac death were 1.3 and
0.3% in the two groups of patients. Myocardial infarction
was observed in 5 (6.3%) patients in the PMI group and 5
(1.4%) in the no PMI group (Figure 1B). Target-vessel revascularization occurred in 10 (12.5%) patients in the PMI group and
Mid-term follow-up of PMI after CTO-PCI
B61
Table 4 Multivariate logistic regression analysis for independent predictors of PMI after CTO-PCI supported by DES
Age
Calcification
Parallel wire technique
Retrograde wire technique
Total stent length
OR
95% CI
P-value
1.018
2.203
3.178
5.554
1.002
0.993–1.044
1.262–3.845
1.661–6.081
2.275–13.558
0.992–1.012
0.155
0.005
,0.001
,0.001
0.748
PMI, periprocedural myocardial injury; CTO, chronic total occlusion; PCI, percutaneous coronary intervention; DES, drug-eluting stent.
Figure 1 Cumulative incidences of MACEs (A), myocardial infarction (B), and target vessel revascularization (C ) the PMI group vs. the no PMI group. MACEs,
major adverse cardiac events; PMI, periprocedural myocardial injury.
19 (5.3%) in the no PMI group (Figure 1C). Overall, there were
significantly statistical differences of MACEs between the
two groups under the dual antiplatelet therapy (adjusted
hazard ratio 3.704; 95% CI 1.759–7.796; P ¼ 0.001; Table 5).
Discussion
The PMI study that enrolled a large cohort of patients (over
400) undergoing successful CTO intervention from 2009 to
2012, for the first time, adopted the new index— cTnT
.5 × the 99th percentile ULN—to indicate that the
independent predictors of the occurrence of PMI after
the successful CTO-PCI and DES implantation included
calcification, the parallel wire technique, and the retrograde wire technique in multivariate analysis. Furthermore, successful CTO-PCI with DESs also demonstrated
that the PMI group after the index procedure, compared
with the no PMI group, was associated with higher
occurrence of MACEs, even under dual antiplatelet
therapy during 3-year follow-up. These results could
improve our understanding of therapeutic intervention
in cardiovascular diseases, especially in the era of DES
implantation.
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X. Zhong et al.
Table 5 Clinical outcomes at 3-year follow-up
Cardiac death
Myocardial infarction
Target vessel revascularization
MACEs
With PMI
Without PMI
Unadjusted HR (95% CI)
P-value
Adjusted HRa (95% CI)
P-value
1/80
5/80
10/80
14/80
1/357
5/357
19/357
23/357
4.133 (0.258–66.204)
4.491 (1.300–15.517)
2.316(1.077–4.982)
2.754 (1.417–5.353)
0.316
0.018
0.032
0.003
—
3.923 (1.013–15.192)
3.708 (1.521–9.044)
3.704 (1.759–7.796)
—
0.048
0.004
0.001
Data are presented as mean + SD or n (%).
PMI, periprocedural myocardial injury; CI, confidence interval; HR, hazard ratio; MACE, major adverse cardiac event
a
Adjusted covariates included male, age ≥75 years, unstable angina, history of smoking, hypertension, diabetes, prior myocardial infarction,
triple-vessel disease, calcification, parallel wire technique, and retrograde wire technique.
The incidence of periprocedural myocardial
injury following successful chronic total
occlusion-percutaneous coronary intervention
with drug-eluting stentss
Periprocedural myocardial injury was not rare, and one
of the prognostically important complications of routine
PCI in cardiovascular diseases. Although published data
about the incidence of PMI could be available online, it
remains a controversial issue for the sake of different biomarkers and thresholds.11 According to the data of a
meta-analysis from 65 studies listing complications after
CTO-PCI, the incidence of periprocedural MI was 2.5%
(95% CI: 1.9–3.0%).19 Contrary to these many articles to referred to, it was reported that there was only one retrospective study focusing on the impact of PMI on clinical
outcomes after successful CTO-PCI.16 Using the definition
of creatine kinase-myocardial band (CK-MB) .3, the
ULN, this retrospective study16 that adopted the retrograde approach in 26.8% of all procedures revealed that
the incidence of PMI was 8.6% (95% CI: 5.8–12.2%) after
successful CTO-PCI. In addition, the frequency of periprocedural cardiac troponin elevation .3×, .10×, and
.20 × ULN was 61, 43, and 31%, respectively. Under
these conditions that a large amount of information
about the prognostic value of the new cut-off point
defined by the third universal definition of MI was not provided by researchers in different heart research centres
around the world, our PMI study took the lead in investigating the clinical outcomes of PMI following the successful
revascularization of CTOs, and indicated that the incidence
of PMI after successful CTO-PCI with DESs was 18.3%. The
finding showed the relatively more accurate estimate of
the occurrence of PMI, compared with the prior study
using old inclusion criteria. The difference in the incidence
of PMI might be mainly attributed to the discrepancy
between evaluation method and PMI definition. The
reason for causing this situation lies in the fact that, compared with data using CK-MB, use of cardiac troponin
would have led to a five-fold or more increase in the diagnosis of PMI.20 Another part for the explanation of this case
was the different characteristics of the population enrolled
in the current study, such as age and calcification. Majority
of the patients with unstable angina (UA) in our study had
‘increasing angina’ even in some ‘certain CTO (angiographically confirmed)’ cases. Although incidence of UA in
this study was higher than many previous studies. The
study by Prasad et al.21 reported as high as 51–72% incidence of UA in CTOs. So, we thought patients with UA
should not be excluded and on the contrary its impact on
PMI and clinical outcomes should be analysed. The result
of our study showed no increase of PMI after CTO-PCI in
this special group.
Procedural factors of periprocedural myocardial
injury following successful chronic total
occlusion-percutaneous coronary intervention
with drug-eluting stents
Due to the advancement of PCI technologies and the improvement of PCI techniques in cardiology during the
most recent time period, great progress has been made in
procedural success rates of revascularization of CTOs.
Howbeit, this benefit was always gained with a discount,
as a result of a number of risk factors associated with clinical complications, like PMI. Iatrogenic injuries to the
vessel and/or myocardium were associated with poor clinical outcomes, similar to the risk factors of baseline and
lesion characteristics, among which, age22,23 and calcification11 have been fully reported in published articles. It is
known to us that the parallel wire technique and the retrograde wire technique overcome technical bottlenecks
for revascularization of CTOs to some extent and, thus,
improve success the rate of CTO-PCI. In this study, the
single-wire technique was the predominant strategy followed by the parallel wire technique. Generally, when
the single-wire technique was applied to fail to run
through the real lumen, then the parallel wire technique
logically became the primary basic technique for
CTO-PCI. Nevertheless, in spite of its contribution to the
success of CTO-PCI, the parallel wire technique seemed
to be associated with significant occurrence of PMI formation. The potential cause was that the first wire had
already entered the subintima, and created a false lumen
before the parallel wire technique was performed.
Even though the second wire increased the success rate
of CTO-PCI, the parallel wire technique could not
remedy, and improve the pre-existing damage to the
artery wall. In recent years, the retrograde wire technique
was commonly performed in daily CTO-PCI. Our finding
about this technique shared the same conclusion with a
previously reported study.16
Mid-term follow-up of PMI after CTO-PCI
B63
Clinical outcomes of periprocedural myocardial
injury following successful chronic total
occlusion-percutaneous coronary intervention
with drug-eluting stents
Medicine, and Dr David Liem from NHLBI Proteomics Center at
UCLA/NHLBI Proteomics Program, UCLA School of Medicine, USA,
for the preparation of the manuscript.
Successful CTO revascularization could potentially bring a
range of clinical benefits to patients, including the improvement of left ventricular function, the prevention of
further ventricular remodelling, and the decrease of the
risk of MACEs. However, real clinical benefits to this population need to be reasonably evaluated in consideration of
the occurrence of complications. Previous studies of
patients undergoing non-emergency PCI, utilizing either
CK-MB myocardial band or troponin to definite PMI, had
shown that PMI was an adverse long-term prognosticator.6–8,22,24 At present, as a new threshold for the definition
of PMI, the clinical outcomes of cTnT .5 × the 99th
percentile ULN to define PMI in PCI-CTO have not been
definitively determined. Hereby, it is very important and
necessary for assessing and detecting potentially harmful
complications of PMI after successful CTO-PCI with DESs.
To determine if UA and other clinical factors have potential impact on our result about MACE, we took these
factors into our Cox proportional hazard models to
adjust the risk of the PMI for clinical outcomes. In the
current study, PMI after successful revascularization of
CTOs was significantly associated with MACEs with the occurrence of 17.5%, emphasizing the fact that there is potential for harm to the collateral circulation, branch
vessel occlusion, or distal embolization when treating
chronic total occluded vessels. Although no statistical difference of cardiac death between two groups was found,
PMI increased the risk of the occurrence of MI and/or TVR,
reflecting that PMI was not benign, and was associated
with adverse clinical events even under the current dual
antiplatelet regimen, which also might result from the
iatrogenic vessel injury involving residual dissection or
subintima stent implantation.
In conclusion, this PMI study demonstrated that as the
new benchmark in PMI defined as cTnT .5 × the 99th percentile ULN, the risk factors of PMI after successful CTO-PCI
with DESs were calcification, the parallel wire technique,
and the retrograde wire technique. The PMI group after
the index procedure, compared with the no PMI group,
was associated with more adverse clinical events under
dual antiplatelet therapy. For making a more convincing
conclusion, further prospective, randomized, and large
clinical studies will be needed to investigate the clinical
implications.
Funding
Limitation
The current study had one limitation that the precise duration of the occlusion was not angiographically documented,
a limitation applicable to all observational studies of CTOs.
Acknowledgement
The authors appreciate the assistance of Dr C.Y. X’avia Chan from
Departments of Physiology and Medicine/CVRL, UCLA School of
This work was supported by State Key Development Program
for Basic Research of China (no. 2011CB503905), National
Key Technology Support Program (no. 2011BAI11B10), and
Major Program of National Natural Science Foundation of
China (no. 81230007).
Conflict of interest: none declared.
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