Coronary Interventions
Culprit Vessel Revascularization Prior to Diagnostic
Angiography as a Strategy to Reduce Delays in Primary
Percutaneous Coronary Intervention
A Propensity-Matched Analysis
Etienne L. Couture, MD; Simon Bérubé, MD; Karl Dalery, MD; André Gervais, MD;
Richard Harvey, MD; Michel Nguyen, MD; Émilie Parenteau, MS; Benoit Daneault, MD
Downloaded from http://circinterventions.ahajournals.org/ by guest on July 28, 2017
Background—Delays are important markers of quality of care in primary percutaneous coronary intervention. There is scarce
data on the impact of obtaining a complete diagnostic angiography before primary percutaneous coronary intervention.
Methods and Results—Consecutive patients treated with primary percutaneous coronary intervention at our institution
between January 2012 and December 2014 were studied. After excluding patients with prior coronary artery bypass
surgery, 925 patients were included in the analysis. Patients were classified into 3 groups according to the as-treated
revascularization strategy: culprit-vessel revascularization first, contralateral angiography first, or complete angiography
first. Propensity score matching was used to minimize difference in clinical characteristics between groups. Predictors
of culprit-vessel first revascularization were anterior/lateral infarct location and absence of diabetes mellitus. After
propensity score matching, the median vascular access-to-balloon time was 4 to 6 minutes shorter with a culprit-vessel
revascularization first strategy. This reduction in time to reperfusion increased the proportion of patients treated within
recommended delays. However, there was no significant difference in 30-day clinical outcomes associated with these
delays reduction.
Conclusions—Performing culprit-vessel primary percutaneous coronary intervention before contralateral or complete
diagnostic angiography is associated with a statistically significant reduction in vascular access-to-balloon time,
although the 4- to 6-minute difference is unlikely to be clinically relevant. This small but significant reduction could
translate in an augmentation in the proportion of patients treated within recommended delays. (Circ Cardiovasc Interv.
2016;9:e003510. DOI: 10.1161/CIRCINTERVENTIONS.115.003510.)
Key Words: coronary angiography ◼ culprit vessel ◼ diabetes mellitus ◼ door-to-balloon time
◼ primary percutaneous coronary intervention
D
obtaining contralateral or complete diagnostic angiography
could be associated with a reduction in delays and outcomes
in ST-segment–elevation myocardial infarction (STEMI)
patients.
elays are important markers of quality of care in primary percutaneous coronary intervention (PPCI).
Door-to-balloon time has been related to mortality, and its
relation seems to be strongest in the early hours of symptom onset.1–8 In this regards, recent American College of
Cardiology/American Heart Association guidelines determine door-to-balloon time goal of <90 minutes for at least
75% of patients admitted initially to a hospital with PPCI
capacity and <120 minutes for at least 90% of transferred
patients.9 Many strategies have been successfully applied
to shorten door-to-balloon time before catheterization laboratory arrival but few have been studied to reduce delays
inherent to the procedure.10–17 Hereof, there is scarce data on
the impact of obtaining a complete diagnostic angiography
before PPCI. Our study sought to determine whether a strategy of performing culprit-vessel revascularization before
Methods
Data Source
Our institution (Center Hospitalier Universitaire de Sherbrooke,
Québec, Canada) is a tertiary care center that maintains an ongoing prospective clinical registry of all STEMI patients undergoing
cardiac catheterizations as already described in a previous study.18
After providing written informed consent, patients were enrolled
into this registry. Clinical and procedural characteristics as well as
important time points were entered in a database. At the time of
the intervention, delays were obtained from nurses, paramedics, and
physicians’ notes. Time for (1) first medical contact, (2) diagnostic
Received December 17, 2015; accepted April 14, 2016.
From the Department of Medicine, Centre Hospitalier Universitaire de Sherbrooke/Université de Sherbrooke, Sherbrooke, Canada (E.L.C., S.B., K.D.,
A.G., R.H., M.N., B.D.); and Department of Medicine, Université de Sherbrooke, Faculty of Medicine, Sherbrooke, Canada (É.P.).
Correspondence to Benoit Daneault, MD, Department of Medicine, Centre Hospitalier Universitaire de Sherbrooke, 3001, 12e Ave Nord, Sherbrooke,
QC, Canada, J1H 5N4. E-mail [email protected]
© 2016 American Heart Association, Inc.
Circ Cardiovasc Interv is available at http://circinterventions.ahajournals.org
1
DOI: 10.1161/CIRCINTERVENTIONS.115.003510
2 Couture et al Culprit First Revascularization to Reduce Delays
Outcomes
WHAT IS KNOWN
• Door-to-balloon time is an important marker of qual-
ity of care in primary percutaneous coronary intervention and has been related to mortality, especially
in the early hours of symptom onset.
• There are scarce data on the safety and utility of
performing culprit-vessel primary percutaneous
coronary intervention before obtaining a complete
angiogram.
WHAT THE STUDY ADDS
• Performing culprit-vessel primary percutaneous corDownloaded from http://circinterventions.ahajournals.org/ by guest on July 28, 2017
onary intervention before contralateral or complete
diagnostic angiography is associated with a small
(4–6 minutes) but statistically significant reduction
in vascular access-to-balloon time.
• This reduction in time to reperfusion translated in a
higher proportion of patients treated within recommended delays.
• Despite improving this quality metric standpoint,
culprit revascularization first strategy was not associated with better or worse clinical outcomes.
ECG, (3) door-in and door-out from referring hospital, (4) door-in
at our institution, (5) arrival of patient in the catheterization laboratory, (6) obtaining vascular access, and (7) first coronary intervention in the culprit artery were all prospectively collected. First
medical contact-to-balloon time (FMBT) delay was calculated from
first medical contact to first coronary intervention with thrombectomy, balloon angioplasty, or direct stenting. Vascular access-toballoon time (VABT) was calculated from time of vascular access
to intervention.
Vital status at 30 days was confirmed for every patient through the
hospital’s computerized database or phone calls made by either our
research or laboratory staff. Medical charts were reviewed to capture
ischemic and bleeding events.
Study Cohort
This is a single-center, retrospective study of all consecutive STEMI
patients treated with PPCI at our institution between January 2012
and December 2014. Inclusion criterion was STEMIs treated with
PPCI. Patients who received fibrinolytic therapy and patients who
were treated medically or referred for coronary artery bypass surgery
(CABG) after coronary angiography were excluded. Patients with
previous CABG were excluded from the study.
All cine-angiography were reviewed by a single investigator
(E.L. Couture). Patients were categorized into 3 groups according
to the strategy used by the operator. Group 1 patients were treated
with culprit vessel ECG-guided percutaneous coronary intervention
(PCI) before undergoing a complete diagnostic coronary angiogram. Group 2 consisted of patients for whom the operator chose
to perform coronary angiography of the culprit vessel with a guiding catheter after imaging the contralateral coronary artery. Group
3 patients underwent complete coronary angiography first with
diagnostics catheters, followed by PCI. When PCI was done after
a contralateral angiogram performed with a guiding catheter on a
nonculprit vessel, the patient was included in group 2. Hence, group
differentiation was based on an as-treated strategy. Culprit coronary
artery was defined as any vessel with an acute thrombotic total or
subtotal occlusion. The choice of the procedural strategy was left at
the discretion of the operator.
The primary outcome of this study was VABT. Secondary outcomes included FMBT, mortality and repeat myocardial infarction
at 30 days, CABG referral <3 months, and in-hospital bleeding
events (bleeding academic research consortium definition for
bleeding ≥3 type).
Statistical Analysis
Data are expressed as counts and percentages for categorical variables and as mean±SD or median (interquartile range) for continuous variables. Statistical comparisons were performed using
χ2 tests for categorical and binary data. Analysis of variance and
Kruskal–Wallis test were used for normally and non-normally distributed continuous data, respectively. Test for an ordered alternative hypothesis within an independent sample was performed with
the Jonckheere trend test.
Multivariable logistic regression models were used to identify
independent predictors of PPCI via a culprit-vessel first strategy.
Candidate variables of interest included demographics, comorbidities, cardiac history, and admission characteristics, as shown in
Table 1. The contribution of each variable to the overall model was
determined using odds ratios. A propensity score-matched cohort
was created to minimize the influence of potential confounders and
selection bias by matching each patient in culprit-vessel revascularization first group with a patient in the contralateral and another in the complete angiography first group using a 3-way 1:1:1
nearest-neighbor matching. For this match, we set the caliper to be
0.6× ((τ2+τ2+τ2)/3)½, where the τ2 values were the average of the
2 observed variances for patients’ 2 propensity scores, with a τ2
value for each treatment group. Patients were excluded from the
matched cohort if they failed to achieve a distance shorter than the
caliper for a given matched trio. This matching method has been
previously described and validated by Rassen et al.19 All baseline
covariates that were associated with treatment assignment (P value
<0.2) were include in the propensity score model. The balance between the 3 matched groups was determined by computing P value
for each explanatory factor.
Treatment times and clinical outcomes were compared before and
after propensity score matching.
Analysis was done using SPSS 23.0 (IBM, Armonk, NY). Threeway 1:1:1 matching was computed using SAS 9.2 (SAS Institute, Inc,
Cary, NC). A P value <0.05 was considered to indicate statistical significance. The study was approved by the local research ethics board.
Results
A total of 949 patients with STEMI were screened during the
study period. Of these, 925 patients met the inclusion criterion and were included in this analysis. The strategy used was
PCI first in 332 patients (36%), contralateral angiography first
in 397 patients (43%), and complete angiography first in 196
patients (21%).
The baseline clinical and procedural characteristics for
the 3 groups before propensity match are shown in Table 1.
Age, prevalence of diabetes mellitus and hypertension, smoking status, and history of prior PCI were significantly different
among the 3 groups before matching. Radial access was used
in 73% of all patients, but femoral access was more frequently
(63%) used with a complete diagnostic angiography strategy.
The multivariable model predictors of culprit-vessel first strategy are shown in Table 2. Three independent predictors of a
culprit-vessel first strategy were identified: (1) absence of diabetes mellitus, (2) radial access, and (3) anterior/lateral infarct
location by ECG. The proportion of these 3 strategies used
by the 6 operators is shown in Figure 1. VABT was significantly different between operators (P=0.006; Figure 2), with
3 Couture et al Culprit First Revascularization to Reduce Delays
Table 1. Baseline Characteristics and Procedural Data Before Matching
Culprit Vessel
Revascularization
First (n=332)
Contralateral
Angiography
First (n=397)
Complete
Angiography
First (n=196)
P Value
Age
61 (54–69)
63 (55–72)
65 (57–73)
0.007
Male
252 (76%)
298 (75%)
140 (71%)
0.50
Weight, kg
78 (68–89)
78 (68–89)
76 (67–86)
0.24
Hypertension
125 (38%)
183 (46%)
103 (53%)
0.003
Diabetes mellitus
43 (13%)
83 (21%)
32 (16%)
0.02
Hyperlipidemia
261 (79%)
332 (84%)
160 (82%)
0.22
Current smoker
187 (56%)
237 (60%)
95 (49%)
0.035
Prior PCI
42 (13%)
41 (10%)
36 (18%)
0.02
Chronic kidney disease
13 (3.9%)
22 (5.5%)
13 (6.6%)
0.36
Cardiogenic shock
25 (7.5%)
27 (6.8%)
18 (9.2%)
0.59
Anterior/Lateral
197 (59%)
153 (39%)
104 (53%)
<0.001
Inferior
135 (41%)
244 (61%)
92 (47%)
<0.001
Radial access
278 (84%)
313 (79%)
71 (36%)
<0.001
Bivalirudin
207 (62%)
304 (77%)
104 (53%)
<0.001
Glycoprotein IIa/IIb inhibitors
61 (18%)
65 (16%)
68 (35%)
<0.001
Clopidogrel
72 (22%)
88 (22%)
54 (28%)
0.25
Prasugrel
68 (21%)
75 (19%)
28 (14%)
0.20
Ticagrelor
195 (59%)
243 (61%)
115 (59%)
0.75
Contrast volume, mL
180 (140–240)
170 (136–200)
160 (125–200)
0.001
Fluoroscopy time, s
485 (306–730)
468 (300–781)
438 (288–633)
0.35
LAD
149 (45%)
112 (28%)
72 (37%)
<0.001
LCX
35 (11%)
46 (12%)
52 (27%)
<0.001
RCA
Baseline characteristics
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Infarct location by ECG
Procedural characteristics
P2Y12 inhibitors
Infarct location by angiography
137 (41%)
228 (57%)
70 (36%)
<0.001
Left main
6 (1.8%)
5 (1.3%)
2 (1.0%)
0.72
Ramus
6 (1.5%)
6 (1.5%)
0 (0%)
0.22
Initial TIMI flow 0–1
277 (83%)
318 (80%)
150 (77%)
0.15
Thrombectomy
281 (85%)
309 (78%)
118 (60%)
<0.001
Drug-eluting stent
158 (48%)
180 (45%)
98 (50%)
0.55
Nonculprit treated first
4 (1.2%)
2 (0.5%)
1 (0.5%)
0.62
Multivessel disease
165 (50%)
187 (47%)
116 (59%)
0.02
Multivessel revascularization at the
time of PPCI
18 (5.4%)
10 (2.5%)
23 (12%)
<0.001
Staged PCI during index hospital stay
33 (9.9%)
40 (10%)
22 (11%)
0.88
Chronic kidney disease indicates serum creatinine >132 μmol/L (1.5 mg/dL). LAD indicates left anterior descending artery; LCX, left circumflex
artery; PCI, percutaneous coronary intervention; PPCI, primary percutaneous coronary intervention; RCA, right coronary artery; and TIMI,
Thrombolysis In Myocardial Infarction.
shorter VABT for those using more frequently a culprit-first
strategy (P for trend <0.001). The operator who used preferentially complete diagnostic angiography first was also the only
operator using preferentially a femoral approach (in >80%) in
comparison to the other 5 operators who used radial access in
>80% of cases. When the femoralist operator was excluded
4 Couture et al Culprit First Revascularization to Reduce Delays
Table 2. Multivariable Predictors of a Culprit-First PPCI Strategy
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Odds Ratio
Estimate
Lower 95% Confidence
Limits for Odds Ratio
Higher 95% Confidence
Limits for Odds Ratio
Wald Chi-Square
Pr>Chi-Square
Age
0.989
0.975
1.002
2.665
0.10
Male
0.989
0.692
1.414
0.004
0.95
Weight
0.998
0.988
1.009
0.094
0.76
Hypertension
0.754
0.553
1.029
3.165
0.08
Diabetes mellitus
0.649
0.432
0.974
4.350
0.037
Hyperlipidemia
0.799
0.554
1.152
1.445
0.23
Current smoker
0.838
0.838
0.617
1.273
0.26
Prior PCI
1.296
0.841
1.999
1.379
0.24
Cardiogenic shock
1.540
0.881
2.693
2.294
0.13
Chronic kidney disease
0.914
0.449
1.861
0.061
0.91
Radial access
2.985
2.086
4.273
35.725
<0.001
Infarct location by ECG inferior vs
anterior/lateral
1.799
1.356
2.385
16.625
<0.001
Chronic kidney disease indicates serum creatinine >132 μmol/L (1.5 mg/dL). PCI indicates percutaneous coronary intervention; and PPCI, primary percutaneous
coronary intervention.
from the multivariable model predictors, radial access was not
anymore a predictor of revascularization strategy (P=0.67).
However, absence of diabetes mellitus and anterior/lateral
infarct location by ECG still predicted culprit-vessel first
strategy.
After propensity score matching, 180 matched trios
were identified. Their baseline characteristics were similar (Table 3). Procedural treatment times and clinical outcomes before and after matching are shown in Table 4.
Before matching, culprit-vessel first strategy was associated
with shorter median VABT (9 versus 11 versus14 minutes;
P<0.001) and shorter median FMBT (99 versus 103 versus
109 minutes; P<0.001) in comparison with contralateral and
complete diagnostic angiography first strategies, respectively. No significant differences in clinical outcomes were
observed.
After matching, the median VABT was 8 minutes (interquartile range [IQ] [6–12]) for the culprit PPCI first group,
12 minutes (IQ [9–15]) for the contralateral angiography first
group, and 14 minutes (IQ [11–17]) for the complete angiography first group (P<0.001 overall and for trend). The median
Figure 1. Histogram showing operator PPCI strategies preferences for the matched cohort. PPCI indicates primary percutaneous coronary intervention.
FMBT was 98 minutes (IQ [84–120]) for the culprit PPCI
first group, 104 minutes (IQ [90–132]) for the contralateral
angiography first group, and 110 minutes (IQ [90–137]) for
the complete angiography first group (P=0.002 overall and
P=0.001 for trend). The net effect was a median reduction of 4
to 6 minutes favoring culprit PPCI first strategy. Culprit PPCI
first increased the proportion of patients treated within FMBT
<90 minutes by 9% and 11% in comparison to contralateral
angiography first and complete angiography first strategies,
respectively (P for trend =0.024; Figure 3). When applied
to an FMBT of <120 minutes, culprit PPCI first increased
the proportion of patients treated within these delays by 7%
and 14% (P for trend =0.007). A linear trend in reduction
of VABT and FMBT was observed between the 3 strategies
(Table 4). In these matched patients, no significant difference
in 30-day mortality and reinfarction was observed between
groups, nor was the rate for CABG referral at 3 months.
Figure 2. Median VABT for each operator after matching. VABT
indicates vascular access-to-balloon time.
5 Couture et al Culprit First Revascularization to Reduce Delays
Table 3. Baseline Characteristics and Procedural Data After Matching
Culprit Vessel Revascularization
First (n=180)
Contralateral Angiography
First (n=180)
Complete Angiography
First (n=180)
P Value
65 (57–73)
64 (55–71)
64 (56–73)
0.60
Baseline characteristics
Age
Male
127 (71%)
137 (76%)
130 (72%)
0.48
Weight, kg
74 (64–86)
79 (69–90)
77 (67–86)
0.02
Hypertension
84 (47%)
94 (52%)
92 (51%)
0.55
Diabetes mellitus
28 (16%)
29 (16%)
28 (16%)
1.000
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Hyperlipidemia
142 (79%)
150 (82%)
147 (81%)
0.58
Current smoker
96 (53%)
107 (59%)
92 (51%)
0.26
Prior PCI
22 (12%)
18 (10%)
33 (18%)
0.056
Chronic kidney disease
11 (6.1%)
9 (5.0%)
10 (5.6%)
0.97
Cardiogenic shock
12 (6.7%)
11 (6.1%)
11 (6.1%)
1.000
Anterior/Lateral
94 (52%)
95 (53%)
95 (53%)
1.000
Inferior
86 (48%)
85 (47%)
85 (47%)
1.000
Radial access
58 (64%)
64 (71%)
60 (67%)
<0.001
Bivalirudin
102 (57%)
137 (76%)
97 (54%)
<0.001
Glycoprotein IIb/IIIa inhibitors
37 (21%)
27 (15%)
65 (36%)
<0.001
Clopidogrel
41 (23%)
43 (24%)
46 (25%)
0.84
Prasugrel
45 (25%)
32 (18%)
26 (14%)
0.03
Infarct location by ECG
Procedural characteristics
P2Y12 inhibitors used loading
Ticagrelor
95 (53%)
112 (62%)
108 (60%)
0.17
Contrast volume, mL
180 (140–248)
170 (140–210)
160 (125–200)
0.01
Fluoroscopy time, s
485 (302–777)
502 (305–813)
423 (276–660)
0.07
LAD
68 (38%)
66 (37%)
64 (36%)
0.92
LCX
19 (11%)
22 (12%)
51 (28%)
<0.001
RCA
88 (49%)
86 (48%)
64 (36%)
0.02
Infarct location by angiography
Left main
4 (2.2%)
3 (1.7%)
1 (0.6%)
0.55
Ramus
1 (0.6%)
3 (1.7%)
0 (0%)
0.33
Initial TIMI flow 0–1
142 (79%)
143 (79%)
138 (77%)
0.84
Thrombectomy
148 (82%)
135 (75%)
111 (62%)
<0.001
Drug-eluting stent
83 (46%)
79 (44%)
92 (51%)
0.38
Nonculprit treated first
3 (1.7%)
0 (0%)
1 (0.6%)
0.33
Multivessel disease
95 (53%)
83 (46%)
103 (57%)
0.11
Multivessel revascularization at the
time of PPCI
13 (7.2%)
4 (2.2%)
22 (12%)
0.001
Staged PCI during index hospital stay
20 (11%)
16 (8.1%)
20 (11%)
0.75
Chronic kidney disease indicates serum creatinine >132 μmol/L (1.5 mg/dL). LAD indicates left anterior descending artery; LCX, left circumflex artery;
PCI, percutaneous coronary intervention; PPCI, primary percutaneous coronary intervention; RCA, right coronary artery; and TIMI, Thrombolysis In Myocardial
Infarction.
Discussion
Although delay reduction in PPCI is essential, there is
scarce data on the safety and efficacy of performing culprit
intervention without complete diagnostic angiogram. This
propensity-matched analysis revealed that performing culprit
PPCI without complete diagnostic angiography significantly
6 Couture et al Culprit First Revascularization to Reduce Delays
Table 4. Procedural Treatment Times and Clinical Outcomes Before and After Matching
Before Matching
After Matching
Culprit Vessel
Revascularization
First (n=332)
Contralateral
Angiography
First (n=397)
Complete
Angiography
First (n=196)
Overall
P
Culprit Vessel
Revascularization
First (n=180)
Contralateral
Angiography
First (n=180)
Complete
Angiography
First (n=180)
Overall
P
P for
Trend
9 (7–12)
11 (9–15)
14 (11–17)
<0.001
8 (6–12)
12 (9–15)
14 (11–17)
<0.001
<0.001
<Median
(11 min)
221 1(67%)
162 (41%)
41 (21%)
<0.001
125 (69%)
70 (39%)
39 (22%)
<0.001
<0.001
FMBT
99 (78–118)
103 (87–130)
109 (90–135)
<0.001
98 (84–120)
0.002
0.001
<60 min
30 (9.0%)
31 (7.8%)
5 (2.6%)
0.02
14 (7.8%)
4 (2.2%)
0.059
0.03
<90 min
128 (39%)
121 (31%)
51 (26%)
0.007
65 (36%)
49 (27%)
45 (25%)
0.049
0.02
<120 min
255 (77%)
274 (69%)
123 (63%)
0.002
136 (76%)
125 (69%)
112 (62%)
0.02
0.007
Total
17 (5.1%)
21 (5.3%)
15 (7.6%)
0.43
10 (5.6%)
12 (6.7%)
12 (6.7%)
0.93
0.75
Cardiovascular
12 (3.6%)
13 (3.3%)
9 (4.6%)
0.73
7 (3.9%)
6 (3.3%)
7 (3.9%)
1.000
1.000
Repeat MI
at 30 days
8 (2.4%)
7 (1.8%)
3 (1.5%)
0.75
4 (2.2%)
6 (3.3%)
3 (1.7%)
0.69
0.87
Index
hospitalization
1 (%)
3 (%)
0 (%)
0.55
1 (0.6%)
1 (0.6%)
0 (0%)
1.000
0.67
<3 mo
1 (%)
7 (%)
0 (%)
0.035
1 (0.6%)
2 (1.1%)
0 (0%)
0.78
0.74
9 (2.7%)
3 (0.8%)
6 (3.1%)
0.07
4 (2.2%)
1 (0.6%)
6 (3.3%)
0.20
0.58
Treatment times, min
VABT
104 (90–132) 110 (90–137)
12 (6.7%)
Clinical outcomes
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Mortality at 30 days
CABG referral
BARC bleeding
≥3 type
BARC indicates Bleeding Academic Research Consortium (definition for bleeding); CABG, coronary artery bypass grafting; FMBT, first medical contact-to-balloon time;
MI, myocardial infarction; and VABT, vascular access-to-balloon time.
shortened delays and improved quality of care measures.
However, these reductions in delays were not associated with
better clinical outcomes.
In this study, an additional 4 to 6 minutes in VABT was
used to complete angiography before PCI and translated into
longer FMBT. These small increments in delays were statistically significant but were unlikely to be clinically relevant
because clinical end points were similar between groups.
However, from a quality metric standpoint, these reductions
in reperfusion delays yielded significant higher percentages
of patients meeting the FMBT goal <90 and <120 minutes.
The magnitude of these changes in proportion of patients
achieving those goals could be exaggerated by unknown
confounding factors. In fact, the VABT reduction of 4 and
6 minutes translated into an FMTB reduction of 6 and 12
minutes in comparison with contralateral and complete angiography first strategy, respectively. Even after matching, the
FMBT reduction was not entirely explained by the VABT
reduction. This suggests that there are unmeasured factors
happening before initiation of the procedure that have not
been accounted for. A reduction of this magnitude is enough
to have dramatic improvement in the proportion of patients
achieving targeted delays because many patients miss these
goals by only a few minutes. In fact, the 90- and 120-minutes
time point are located on the steepest part of the FMBT distribution curve (Figure 4).
In PPCI, the therapeutic goal is clear; it is to restore blow
flow to the culprit artery as quickly as possible. It is not surprising that the rate of PCI is high and only rarely emergent
CABG is used.20 Even in patients with triple vessel or left
main disease, PCI of the occluded artery should be done
promptly, leaving the residual disease to be treated later.
CABG after acute coronary syndrome is now frequently
performed under dual antiplatelet therapy (using clopidogrel) and not associated with worse outcomes.21 Performing
complete angiography before PCI could (1) avoid treating a
Figure 3. Histogram proportion of STEMI patients treated within
appropriate FMBT goals according to PPCI strategies for the
matched cohort. FMBT indicates first medical contact-to-balloon
time; PPCI, primary percutaneous coronary intervention; and
STEMI, ST-segment–elevation myocardial infarction.
7 Couture et al Culprit First Revascularization to Reduce Delays
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Figure 4. FMBT distribution curve for the matched cohort. FMBT
indicates first medical contact-to-balloon time.
nonculprit artery first and (2) influence therapeutics in some
patients with restored flow to the culprit artery and multivessel disease. Our descriptive analyses of predictors of culpritvessel first revascularization strategy revealed that absence
of diabetes mellitus and anterior/lateral infarct location were
the 2 independent factors influencing strategy selection.
Diabetes mellitus is linked to multivessel disease, and physicians likely preferred to define complete anatomy before
engaging into PCI in that population, especially for those
with restored flow. Right coronary anatomy is not likely to
influence therapeutic for anterior infarcts, nor is expected to
reveal the culprit artery. Hence, most physicians probably
felt comfortable to defer right coronary angiography in anterior infarcts. For inferior infarcts, ECG is not as reliable to
reveal the culprit artery. A study evaluating delays according to the culprit artery found longer delays for left circumflex artery compared with right coronary and left anterior
descending artery.22 This could be explained by engaging in
PCI of a nonculprit right coronary artery while left circumflex artery is the culprit. To avoid this, imaging the contralateral vessel first could be a preferred strategy. There are likely
some unknown confounders in our study that favored a strategy over another. Atypical and late presentation, diagnostic
uncertainty, and unexplained shock are factors that could
influence experienced operators to obtain complete angiography, whereas complete AV block and recurrent ventricular
fibrillation in inferior myocardial infarction could lead them
to hustle the process of restoring flow to a culprit right coronary artery.
Our finding of a small but statistically significant
decrease of 4 to 6 minutes in VABT is consistent with,
but remains lowers in magnitude than those previously
reported.13–17 In a large strictly radial access study, culprit
first revascularization reduced door-to-balloon time by a
median time of 8 minutes.14 This study, however, did not
report VABT. Smaller studies with femoral access showed
larger reduction in VABT of ≤13 minutes.15–17 The high
number of PPCI performed by our operators (>50 PPCI/y;
>250 PCI/y) and our propensity-matched analysis might
explain why we observed lower differences in delays than
previous studies.
The absence of difference in clinical outcomes despite
shorter delays is likely explained by the magnitude of delay
reduction. A reduction of 5 to 10 minutes is unlikely to translate into better survival, and our observations bed well with
other recent publications that failed to show lower mortality despite reduction in door-to-balloon time.23–26 The old
adage, time is muscle, is an attractive explanation for outcome, but studies correlating total ischemic time to mortality also showed divergent results.26–29 Together, these studies
tend to demonstrate that delays reduction seems to exert its
mortality benefit mostly in STEMI patients treated in the
early hours (<4–6 hours) after symptom onset. Prior animal study at the origin of the wavefront phenomenon concept elaboration also pointed out in that direction when they
documented the presence of a subepicardial zone of ischemic but viable myocardium which is available for salvage
for at least 3 and perhaps 6 hours after circumflex occlusion
in dogs.30 Furthermore, the contribution of radial access to
better outcome may bias our interpretation of the relation
between delays and outcomes. As Wimmer et al have proposed it in a decision-analytic model, a transradial delay of
83 minutes was needed to offset the 30-day mortality benefit
of transradial PPCI.31 Moreover, after propensity matching,
our sample was not powered to detect more than a 30-day
mortality difference of 2%.
In light of these results, several limitations need to be
acknowledged. Because of the retrospective design, revascularization strategy was not randomized. Although we
adjusted for differences in baseline presenting characteristics by using propensity score matching, there may have
been residual confounders because of unmeasured patient’s
variables. For example, multivessel revascularization at the
time of PPCI was more frequent in the complete angiography first group. This procedural characteristic might reflect
the presence of some unmeasured baseline characteristics
that could have influenced the operator’s strategy (eg, possibility of multiple culprits based on clinical presentation
and ECG). Differences in few procedural characteristics
are likely related to differences in operators’ preferences
because each of them were not equally distributed in each
treatment group. However, it is unlikely that these differences have had an impact on our primary issue consisting
of reperfusion delays. We did not adjust for the various
operators in our analysis because a multivariable regression
analysis looking at predictors of shorter VABT revealed that
the only predictors of shorter VABT were revascularization
strategies (P<0.001). More else, Figures 1 and 2 demonstrated that a shorter mean VABT is associated with operators using more frequently a culprit-first strategy (overall P
and P for trend <0.001). Together, these data demonstrated
that the VABT is closely associated with strategy selection
rather than operator by themselves. Our study did not evaluate reliably the initial intention-to-treat revascularization
strategy. Culprit artery localization on initial ECGs is not a
perfect science, and this is why we did group differentiation
based on the as-treated strategy determined by the angiogram. Follow-up for clinical events was short but probably
sufficient to test for the procedurals effects of PPCI, and
these data were collected prospectively. However, based
8 Couture et al Culprit First Revascularization to Reduce Delays
on the overall 30-days mortality rate, we estimate that our
propensity-matched cohort had the power to detect a 4%
mortality difference between groups. A sample of 8151
would be needed to detect a 1% difference.
Conclusions
Based on our observations, it seems safe to perform PPCI without obtaining contralateral angiography first in selected cases,
especially anterior infarcts. This strategy is associated with
a small reduction in FMBT, and a significant increase in the
proportion of patients achieving target delays was observed,
although the latter was likely overestimated because of
unknown confounders. Obtaining complete angiography first
was not associated with better or worse clinical outcomes. Clinical judgment should be used to optimize care in these patients.
Downloaded from http://circinterventions.ahajournals.org/ by guest on July 28, 2017
Acknowledgments
We thank Catherine Allard, MSc, for statistical assistance.
Disclosures
None.
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Culprit Vessel Revascularization Prior to Diagnostic Angiography as a Strategy to Reduce
Delays in Primary Percutaneous Coronary Intervention: A Propensity-Matched Analysis
Etienne L. Couture, Simon Bérubé, Karl Dalery, André Gervais, Richard Harvey, Michel
Nguyen, Émilie Parenteau and Benoit Daneault
Downloaded from http://circinterventions.ahajournals.org/ by guest on July 28, 2017
Circ Cardiovasc Interv. 2016;9:
doi: 10.1161/CIRCINTERVENTIONS.115.003510
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