Understanding Operator Stent Choice in the Catheterization Laboratory Using a PreProcedure Survey: Opportunities for Quality Improvement
Matthew J. Chung, MD1, Jonathan D. Hansen, MD, MPH2, Ryan D. Schulteis, MD, MS2,3, Joel
C. Boggan, MD, MPH2,3, W. Schuyler Jones, MD2,3,4, Thomas J. Povsic, MD, PhD2,3,4, Susan
Roberts, ANP3, Mitchell W. Krucoff, MD2,3,4, Sunil V. Rao, MD2,3,4
1
Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri,
Department of Medicine, Duke University Medical Center, Durham, North Carolina, 3Durham
Veterans Affairs Medical Center, Durham, North Carolina, 4Duke Clinical Research Institute,
Durham, North Carolina
2
Corresponding Author:
Matthew J. Chung, MD
Cardiovascular Division
Washington University School of Medicine
Campus Box 8086
660 S. Euclid Avenue
St. Louis, MO 63110
Fax: (314) 362-9128
Phone: (314) 362-1291
Email: [email protected]
Authors’ contributions: MJC, RDS, and SVR conceived the study design, interpreted the data
and drafted the manuscript; all authors revised the manuscript for important intellectual content
and gave final approval of the manuscript
Running head: Factors Affecting Stent Type During PCI
Financial support: None.
Conflicts of interest: None.
Word count: 3387 (including abstract, text, references and figure legends)
This is a post-referee version. Publisher version available:
http://www.cardiorevascmed.com/article/S1553-8389(17)30167-7/fulltext. Full citation:
Chung MJ, Hansen JD, Schulteis RD, Boggan JC, Jones WS, Povsic TJ, Roberts S, Krucoff
MW, Rao SV. Cardiovasc Revasc Med. 2017 May 8. pii: S1553-8389(17)30167-7. doi:
10.1016/j.carrev.2017.05.004. [Epub ahead of print]
1
Keywords: percutaneous coronary intervention, drug-eluting stents, quality improvement,
surveys and questionnaires
2
Abstract
Objectives
We sought to characterize how the perceived risk of early dual antiplatelet therapy (DAPT)
discontinuation is incorporated into operator decision-making regarding stent choice, using a
simple pre-procedure survey screening for clinical variables that may lead to early DAPT
discontinuation.
Background
Understanding which factors influence operator decision-making regarding stent choice during
percutaneous coronary intervention (PCI) could help identify areas for quality improvement.
Methods
We retrospectively identified 1202 patients who underwent PCI from July 2008 to January 2013
at the Durham Veterans Affairs Medical Center. We excluded patients without a complete preprocedure survey within 14 days of PCI, repeat procedures on the same patient and those who
received both drug-eluting stents (DES) and bare-metal stents (BMS) or no stent during PCI,
leaving 864 patients. The primary outcome was the independent association of “yes” responses
to survey items with the odds of DES use during PCI.
Results
Of 864 patients, 661 received DES and 203 received BMS. A “yes” response to “planned major
surgery or dental work in the next year” (OR 0.20, 95% CI 0.11-0.36, p<0.001), “recent bleeding
event or bleeding diathesis” (OR 0.31, 95% CI 0.14-0.68, p=0.003) and “currently taking
3
Coumadin” (OR 0.39, 95% CI 0.19-0.78, p=0.007) was independently associated with lower
odds of DES use.
Conclusions
Responses to 3 items on a simple pre-procedure survey screening for clinical variables that may
lead to early DAPT discontinuation were independently associated with stent type used during
PCI, suggesting the importance of these factors in an operator’s stent choice.
4
Introduction
Drug-eluting stents (DES) have been shown to reduce angiographic restenosis and target
vessel revascularization compared with bare-metal stents (BMS). However, current guidelines
recommend a longer duration of dual antiplatelet therapy (DAPT) after DES implantation due to
a delay in neointimal coverage of the stent struts.(1-3) Furthermore, early DAPT discontinuation
has been shown to be strongly associated with stent thrombosis, a potentially devastating event
that can lead to significant morbidity and mortality.(4, 5) Although the gap between required
duration of DAPT after DES and BMS is narrowing with newer stent technologies, it remains
useful to understand how operators incorporate the perceived risk of early DAPT discontinuation
into decisions regarding stent choice.(6) Such information could help elucidate differences in
practice patterns between operators and potentially identify areas for quality improvement as the
paradigm shifts towards the use of DES in nearly all situations. In July 2008, we incorporated a
simple pre-procedure survey into the local electronic health record for all patients being
evaluated for cardiac catheterization. This survey screened for clinical variables that may lead to
early DAPT discontinuation. In this study, we sought to evaluate the utilization of this survey.
We hypothesized that a “yes” response to any survey item would be associated with stent type
used during percutaneous coronary intervention (PCI), since the risk of stent thrombosis with
early DAPT discontinuation is higher for DES compared with BMS in the early post-PCI period.
Methods
We performed a single center, retrospective cohort study at the Durham Veterans Affairs
Medical Center, a 271-bed tertiary care hospital in Durham, NC. Using the Durham Veterans
Affairs Medical Center electronic health record, we identified all patients who underwent PCI
5
over 54 months from July 2008 to January 2013. We excluded patients without a complete preprocedure survey within 14 days of PCI, repeat procedures on the same patient and those who
received both DES and BMS or no stent during PCI (Figure 1). During this time period,
clopidogrel was the only thienopyridine used after PCI and Coumadin (warfarin) was the only
oral anticoagulant used at our institution.
The pre-procedure survey included 6 yes/no questions: 1) Currently taking Coumadin?
2) Major surgery within the last week? 3) Planned major surgery or dental work in the next
year? 4) Recent bleeding event or bleeding diathesis? 5) History of medication noncompliance?
6) Is the patient anemic (hematocrit ≤ 30%)? The first 5 questions were asked to patients by a
healthcare provider prior to undergoing cardiac catheterization and the hematocrit was
determined from pre-procedure laboratory studies. The responses to the survey were entered into
the electronic health record as part of the mandatory pre-catheterization assessment. Once
completed, this assessment was reviewed and signed by the interventional cardiology attending
prior to the procedure.
We evaluated the utilization of the pre-procedure survey by determining the association
of “yes” responses to survey items with the odds of DES use during PCI. The primary outcome
was the use of DES during PCI. The DES platforms available at the DVAMC during the study
period were the Xience Prime (Abbott Vascular, Santa Clara, CA) and the Resolute Integrity
(Medtronic Vascular, Minneapolis, MN).
To reduce the bias of intra-class correlation or clustering, we limited our analysis to the
first PCI for each patient during the study period. We determined baseline characteristics of the
patients as shown in Table 1. We first performed univariate logistic regression to determine the
6
association between baseline characteristics of the patients and DES use during PCI. Age,
hyperlipidemia, congestive heart failure, peripheral vascular disease, serum creatinine, shock on
presentation and PCI indication were significantly associated with DES use (p<0.10 for the
univariate analysis). Although we planned to include sex in the univariate analysis, there were
only 12 females in the study, all of whom received a DES; thus, we were unable to estimate the
effect of sex due to the marked imbalance. Sensitivity analysis revealed no significant change in
the results when excluding these patients from the analysis. We then performed multivariate
logistic regression, adjusting for age, hyperlipidemia, congestive heart failure, peripheral
vascular disease, serum creatinine, shock on presentation, PCI indication and survey responses,
to determine the independent association between “yes” responses to survey items and DES use.
Sensitivity analysis including patients who received both DES and BMS as part of the DES
group resulted in no significant changes in the point estimates or statistical significance of the
odds ratios in the multivariate model. All analyses were conducted in R (Vienna, Austria). The
study was approved by the Durham Veterans Affairs Medical Center institutional review board,
which provided a waiver of informed consent due to the retrospective nature of the study.
Results
During the study period, 1202 patients underwent PCI at the Durham Veterans Affairs
Medical Center with 864 patients meeting the inclusion/exclusion criteria. The baseline
characteristics of the study patients are shown in Table 1. Of 864 patients, 661 (76.5%) received
DES and 203 (23.5%) received BMS. The average age of the study patients was 64 years old and
the majority of patients were male (98.6%). The majority of patients had hypertension (82.6%)
and hyperlipidemia (63.8%). Approximately 45.8% of the patients had diabetes mellitus. The
7
most common indication for PCI was unstable angina or NSTEMI (55.1%), followed by stable
angina (25%) and lastly STEMI (13.5%). Most of the target vessels were native vessels (90.3%)
rather than vein grafts (9.7%).
In the univariate analysis, age, hyperlipidemia, congestive heart failure, peripheral
vascular disease, serum creatinine, shock on presentation and PCI indication were significantly
associated with DES use (p<0.10) as shown in Table 2. Increasing age (OR 0.97 per 1 year
increase in age, 95% CI 0.96-0.99, p<0.01), congestive heart failure (OR 0.72, 95% CI 0.491.05, p=0.085), peripheral vascular disease (OR 0.61, 95% CI 0.41-0.95, p=0.024), increasing
creatinine (OR 0.90 per 1 mg/dl increase in creatinine, 95% CI 0.80-1.01, p=0.058), shock on
presentation (OR 0.15, 95% CI 0.02-0.78, p=0.03) and presentation with STEMI (OR 0.41, 95%
CI 0.25-0.66, p<0.001) compared with stable angina significantly decreased the odds of DES
use. Hyperlipidemia (OR 1.56, 95% CI 1.13-2.15, p=0.006) and presentation with unstable
angina or NSTEMI (OR 1.90, 95% CI 1.28-2.81, p = 0.001) compared with stable angina
significantly increased the odds of DES use. Race, ethnicity, cigarette smoking status,
hypertension, diabetes mellitus, prior cerebrovascular accident and target vessel type (native vs.
vein graft) were not significantly associated with DES use.
After adjusting for survey responses and variables that were significantly associated with
DES use on univariate analysis, we found that a “yes” response to 3 of 6 items on the survey was
independently associated with a decrease in the odds of DES use (Table 3). The survey item
“planned major surgery or dental work in the next year” had the strongest effect (OR 0.20, 95%
CI 0.11-0.36, p<0.001), followed by “recent bleeding event or bleeding diathesis” (OR 0.31,
95% CI 0.14-0.68, p=0.003) and “currently taking Coumadin” (OR 0.39, 95% CI 0.19-0.78,
8
p=0.007). There was a non-significant trend towards decreased DES use in association with a
“yes” response to the survey item “history of medication noncompliance” (OR 0.53, 95% CI
0.27-1.10, p=0.06) and no association with a “yes” response to the survey item “is the patient
anemic (hematocrit ≤ 30%)” (OR 0.50, 95% CI 0.18-1.40, p=0.19) and “major surgery within the
last week” (OR 0.56, 95% CI 0.13-2.50, p=0.43). There was a strong inverse correlation with the
total number of “yes” responses to survey items and the rate of DES use; there was 83.5% DES
use among those with 0 “yes” responses, 61.1% DES use with 1 “yes” response, 40.6% DES use
with 2 “yes” responses and 0% DES use with 3 “yes” responses.
Discussion
In this single-center, retrospective analysis, we evaluated the association between
responses to a simple electronic health record integrated pre-procedure survey, screening for
clinical variables that may lead to early DAPT discontinuation, with stent type used during PCI.
We found that age, PCI indication and responses to 3 of 6 survey items were associated with
stent type used during PCI. This suggests that in addition to traditional patient characteristics,
these 3 survey items played an important role in an operator’s stent choice. Integration of this
survey into the patient’s electronic health record as part of the pre-procedure evaluation is
aligned with the meaningful use of electronic health data and would provide insight into which
factors influence an operator’s stent choice. Understanding an operator’s decision-making
process when choosing between DES and BMS could aid in targeting potential areas for quality
improvement. Furthermore, since operator preferences regarding stent type vary across
catheterization laboratories, it is important to implement surveys, such as ours, that will increase
9
understanding of physician preferences, as the next step will be to understand patient preferences
as well.
In our study, we found that the survey item that was most strongly associated with an
operator’s decision to avoid DES use during PCI was “planned major surgery or dental work in
the next year.” This was an enlightening finding since studies have suggested that there are
misconceptions about which procedures warrant interruption of DAPT.(7) In the ACDC
(Adherence to Treatment of Coronary Patients After a Catheterization with DES Implantation)
study, of 83 cases where DAPT was discontinued early due to an invasive procedure, the
majority (57.8%) of these were minor procedures during which DAPT could have been
continued without excessive bleeding risk.(8) Thus, a mutual understanding by both the
interventional cardiologist and subsequent providers of which procedures warrant interruption of
DAPT could lead to improved utilization of DES and potentially better outcomes. Furthermore,
patients should be instructed before hospital discharge to contact their treating cardiologist
before stopping DAPT, even if instructed to do so by another healthcare provider.(7) We also
found that the survey item “currently taking Coumadin” decreased an operator’s likelihood of
using DES during PCI. This also offers a potential target for improved patient selection for DES
since there are emerging data and ongoing studies regarding the optimal duration of “triple
therapy” to balance ischemic and bleeding risks in patients who require anticoagulation and
undergo PCI with stenting. In the randomized, controlled WOEST (What is the Optimal
antiplatElet and anticoagulant therapy in patients with oral anticoagulation and coronary
StenTing) trial, the investigators found that oral vitamin K antagonist (VKA) therapy with
clopidogrel significantly reduced bleeding complications with no increase in the rate of
thrombotic events compared with triple therapy using a VKA, clopidogrel and aspirin.(9) Lastly,
10
we found that the survey item “history of medication noncompliance” also was associated with a
trend towards decreased DES use during PCI. This multifaceted clinical factor remains critically
important and is the subject of ongoing research aiming to find interventions that improve
compliance.(10) Importantly, medication compliance is not exclusively the patient’s
responsibility, but rather an issue that is critically influenced by both healthcare providers and
the healthcare system.
In regards to clinical guidelines, the current recommendations for PCI are to avoid DES
use in patients with financial or social barriers to DAPT, high bleeding risk, need for invasive
procedures and concern for noncompliance.(1, 11) As newer stent technologies evolve and the
required duration of DAPT after stenting with DES or BMS becomes similar, these guidelines
will likely change to reflect the preferred use of DES in most situations.(6) Throughout this
transition, the use of a survey that reflects an operator’s decision-making process would be
useful to track changing treatment paradigms at the physician level, as well as to ensure
standardization of care across different catheterization laboratories. Our study evaluated
implementation of such a survey and found that responses to survey items were associated with
stent type used during PCI, thus demonstrating the importance of this information in the
decision-making process regarding stent choice.
Our study has several potential limitations. First, our study was conducted at a single
Veterans Affairs Medical Center and as such, may not be generalizable to other populations.
Second, our study cohort lacked a sufficient number of females for analysis. Third, our study
reflects local practice patterns that may vary across different institutions. Fourth, our analysis
included a limited number of baseline covariates; thus, it is possible that there were unmeasured
11
covariates (e.g. lesion characteristics) that could change the association of responses to survey
items and stent type used during PCI. However, other important covariates that have been
shown to be associated with DES use during PCI, such as insurance status, are of limited
consequence in the Veterans Affairs healthcare system.(12, 13) Fifth, our survey has not been
validated as an accurate predictor of early DAPT discontinuation; however, its components have
been shown in studies to correlate well with early DAPT discontinuation or are consistent with
guidelines recommendations.(1, 8, 11, 14, 15) Sixth, only clopidogrel and warfarin were used in
our study and with the availability of newer P2Y12 inhibitors and non-vitamin K oral
anticoagulants, reassessing the utility of the survey with updated questions will be important.
Finally, our study was not designed to assess the effect of the survey on clinical outcomes;
rather, this was a preliminary study to evaluate the utility of a new clinical tool and assess its
ability to reflect operator decision-making regarding stent choice. Furthermore, it should be
recognized that stent choice during PCI is a complex decision involving many factors, and our
study captures only some of these factors that pertain, in particular, to the risk of early DAPT
discontinuation.
Conclusions
We found that age, PCI indication and responses to 3 items on a simple pre-procedure
survey screening for clinical variables that may lead to early DAPT discontinuation were
associated with stent type used during PCI, suggesting the importance of these factors in an
operator’s stent choice. Future studies should assess whether implementation of such a survey
helps identify areas for quality improvement and leads to improved outcomes through improved
utilization of DES. Furthermore, widespread integration of this survey into the electronic health
12
record may provide insight into operator decision-making across different catheterization
laboratories and subsequent opportunities for standardization of care and further research.
13
Acknowledgments
None.
14
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Figure Legends.
Figure 1. Analytical cohort.
The derivation of the analytical cohort is shown. PCI = percutaneous coronary intervention;
DES = drug-eluting stent; BMS = bare-metal stent.
19
Tables.
Table 1. Baseline Characteristics of the Study Patients
Clinical Variable
Age, yr*
Sex, no. (%)
Male
Female
Race, no. (%)
White
Non-white
Ethnicity, no. (%)
Hispanic or Latino
Non-Hispanic or Latino or Unknown/Declined to Answer
Cigarette smoking status, no. (%)
Never smoker
Former smoker
Current smoker
Unknown
Hypertension, no. (%)
Diabetes mellitus, no. (%)
Hyperlipidemia, no. (%)
Congestive heart failure, no. (%)
Peripheral vascular disease, no. (%)
Prior cerebrovascular accident, no. (%)
Serum creatinine, mg/dl*
Shock on presentation, no. (%)
All Patients
(N = 864)
Bare-Metal Stent
(N = 203)
Drug-Eluting Stent
(N = 661)
P Value
64.2 ± 8.6
65.7 ± 9.2
63.7 ± 8.3
0.007
0.09
852 (98.6)
12 (1.4)
203 (100)
0 (0)
649 (98.2)
12 (1.8)
600 (69.4)
264 (30.6)
136 (67.0)
67 (33.0)
464 (70.2)
197 (29.8)
0.44
0.69
8 (0.9)
856 (99.1)
1 (0.5)
202 (99.5)
7 (1.1)
654 (98.9)
0.75
156 (18.0)
387 (44.8)
245 (28.4)
76 (8.8)
714 (82.6)
396 (45.8)
551 (63.8)
168 (19.4)
120 (13.9)
93 (10.8)
1.37 ± 1.27
6 (0.7)
33 (16.3)
91 (44.8)
58 (28.6)
21 (10.3)
164 (80.8)
89 (43.8)
113 (55.7)
48 (23.6)
38 (18.7)
26 (12.8)
1.53 ± 1.66
4 (2.0)
123 (18.6)
296 (44.8)
187 (28.3)
55 (8.3)
550 (83.2)
307 (46.4)
438 (66.3)
120 (18.2)
82 (12.4)
67 (10.1)
1.33 ± 1.11
2 (0.3)
0.43
0.52
0.006
0.085
0.024
0.284
0.058
0.03
20
Indication, no. (%)
Stable angina
Unstable angina / NSTEMI
STEMI
Unknown
Target vessel type, no. (%)
Native
Vein graft
<0.001
216 (25.0)
476 (55.1)
117 (13.5)
55 (6.4)
56 (27.6)
74 (36.4)
54 (26.6)
19 (9.4)
160 (24.2)
402 (60.8)
63 (9.5)
36 (5.5)
0.84
780 (90.3)
84 (9.7)
184 (90.6)
19 (9.4)
596 (90.2)
65 (9.8)
*Mean ± standard deviation is presented for age and serum creatinine. NSTEMI = non-ST-elevation myocardial infarction;
STEMI = ST-elevation myocardial infarction
21
Table 2. Univariate Analysis of Clinical Variables on Odds of Drug-Eluting Stent Use During Percutaneous Coronary Intervention
Clinical Variable*
Odds Ratio
95% CI
P Value
Age
0.97
0.96 - 0.99
0.004
Race
Non-white
0.86
0.62 - 1.21
0.39
Ethnicity
Hispanic or Latino
2.16
0.38 - 40.54
0.47
Cigarette smoking status
Former smoker
0.87
0.55 - 1.36
0.55
Current smoker
0.87
0.53 - 1.40
0.56
Hypertension
1.18
0.78 - 1.75
0.43
Diabetes mellitus
1.11
0.81 - 1.53
0.52
Hyperlipidemia
1.56
1.13 - 2.15
0.006
Congestive heart failure
0.72
0.49 - 1.05
0.085
Peripheral vascular disease
0.61
0.41 - 0.95
0.024
Prior cerebrovascular accident
0.77
0.48 - 1.26
0.28
Serum creatinine
0.90
0.80 - 1.01
0.058
Shock on presentation
0.15
0.02 - 0.78
0.03
Indication
Unstable angina / NSTEMI
1.9
1.28 - 2.81
0.001
STEMI
0.41
0.25 - 0.66
<0.001
Target vessel type
Vein Graft
1.06
0.63 - 1.85
0.84
*Sex was not included in the analysis because there were only 12 females
in the study cohort, all of whom received drug-eluting stents; as such, we
were unable to estimate the effect of sex due to the marked imbalance. CI
= confidence interval; NSTEMI = non-ST-elevation myocardial
infarction; STEMI = ST-elevation myocardial infarction.
22
Table 3. Multivariate Analysis of a “Yes” Response to a Survey Item on the Odds of Drug-Eluting Stent Use During
Percutaneous Coronary Intervention
Pre-Procedure Survey Item
1. Currently taking Coumadin?
2. Major surgery within the last week?
3. Planned major surgery or dental work in the next year?
4. Recent bleeding event or bleeding diathesis?
5. History of medication noncompliance?
6. Is the patient anemic (hematocrit ≤ 30%)?
Number of "yes" responses /
Number of total responses
Adjusted Odds Ratio*
95% CI
P Value
53 / 833
12 / 845
81 / 813
40 / 838
59 / 827
26 / 761
0.39
0.56
0.20
0.31
0.53
0.50
0.19-0.78
0.13-2.50
0.11-0.36
0.14-0.68
0.27-1.10
0.18-1.40
0.007
0.43
<0.001
0.003
0.06
0.19
*Adjusted for age, hyperlipidemia, peripheral vascular disease, congestive heart failure, shock on presentation, serum creatinine, PCI indication and
survey responses; CI = confidence interval.
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Figures.
Figure 1.
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