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Original Articles
Impact of Incomplete Revascularization on Long-Term
Mortality After Coronary Stenting
Chuntao Wu, MD, PhD; Anne-Marie Dyer, MS; Spencer B. King III, MD; Gary Walford, MD;
David R. Holmes, Jr, MD; Nicholas J. Stamato, MD; Ferdinand J. Venditti, MD;
Samin K. Sharma, MD; Icilma Fergus, MD; Alice K. Jacobs, MD; Edward L. Hannan, PhD
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Background—The impact of incomplete revascularization (IR) on adverse outcomes after percutaneous coronary
intervention remains inconclusive, and few studies have examined mortality during follow-ups longer than 5 years. The
objective of this study is to test the hypothesis that IR is associated with higher risk of long-term (8-year) mortality after
stenting for multivessel coronary disease.
Methods and Results—A total of 13 016 patients with multivessel disease who had undergone stenting procedures with
bare metal stents in 1999 to 2000 were identified in the New York State’s Percutaneous Coronary Intervention Reporting
System. A logistic regression model was fit to predict the probability of achieving complete revascularization (CR) in
these patients using baseline risk factors; then, the CR patients were matched to the IR patients with similar likelihoods
of achieving CR. Each patient’s vital status was followed through 2007 using the National Death Index, and the
difference in long-term mortality between IR and CR was compared. It was found that CR was achieved in 29.2% (3803)
of the patients. For the 3803 pair-matched patients, the respective 8-year survival rates were 80.8% and 78.5% for CR
and IR (P⫽0.04), respectively. The risk of death was marginally significantly higher for IR (hazard ratio⫽1.12; 95%
confidence interval, 1.01–1.26, P⫽0.04). The 95% bootstrap confidence interval for the hazard ratio was 0.98 to 1.32.
Conclusions—IR may be associated with higher risk of long-term mortality after stenting with BMS in patients with multivessel
disease. More prospective studies are needed to further test this association. (Circ Cardiovasc Interv. 2011;4:413-421.)
Key Words: coronary angioplasty 䡲 coronary artery disease 䡲 long-term follow-up 䡲 mortality 䡲 stenting
A
though percutaneous coronary intervention (PCI) is a
commonly used revascularization procedure for patients
with multivessel coronary artery disease, the impact of
incomplete revascularization (IR) on adverse outcomes after
PCI is still inconclusive.1–21 Some of the studies before the
stent era have examined the impact of IR for coronary
angioplasty,3–11 which has now been largely replaced by
coronary stenting. The more recent studies using data from
the stent era examined short- and intermediate-term outcomes
with lengths of follow-up usually less than 3 years.12–21
However, there is a lack of data on adverse outcomes such as
mortality and major adverse cardiac events (MACE) in the
long term, especially 5 or more years. Because the observed
short- and intermediate-term effects of IR may be different
than the long-term impact, there is a need for studies that
examine long-term adverse outcomes data after PCI with IR
or complete revascularization (CR).
Our group has conducted 2 studies that have found that IR
was associated with higher risk of 3-year mortality in the bare
metal stent (BMS) era17 and 18-month mortality in the
drug-eluting stent era (DES).20 Building on our past research,
the present study examines the impact of IR on long-term
mortality for coronary stenting with BMS. We tested the
hypothesis that incomplete revascularization is associated
with higher risk of long-term (8-year) mortality after coronary stenting with BMS.
Methods
Databases
The databases used in this study include the databases of the New
York State’s Percutaneous Coronary Intervention Reporting System
(PCIRS) and Cardiac Surgery Reporting System (CSRS) and the
National Death Index. The PCIRS contains all PCI procedures
performed in nonfederal hospitals in New York State. The data
collected in the PCIRS include patient demographics, preprocedural
Received April 20, 2011; accepted July 27, 2011.
From the Penn State Hershey College of Medicine, Hershey, PA (C.W., A.D.); St Joseph’s Health System, Atlanta, GA (S.B.K.); Johns Hopkins
Medical Center, Baltimore, MD (G.W.); Mayo Clinic, Rochester, MN (D.R.H.); United Health Services, Binghamton, NY (N.J.S.); Albany Medical
College, Albany, NY (F.J.V.); Mt Sinai Medical Center, New York, NY (S.S.); Harlem Hospital, New York, NY (I.F.); Boston Medical Center, Boston,
MA (A.K.J.); and University at Albany, State University of New York, Albany, NY (E.L.H.).
The views expressed are those of the authors and do not necessarily reflect those of the New York State Department of Health. An abstract based on
part of this study was presented at the American Heart Association, 2010 Scientific Sessions, Chicago, IL; November 13–17, 2010.
Correspondence to Chuntao Wu, MD, PhD, Penn State Hershey College of Medicine, Academic Support Bldg, Suite 2200, A210, 600 Centerview Dr,
Hershey, PA 17033. E-mail [email protected]
© 2011 American Heart Association, Inc.
Circ Cardiovasc Interv is available at http://circinterventions.ahajournals.org
413
DOI: 10.1161/CIRCINTERVENTIONS.111.963058
414
Circ Cardiovasc Interv
October 2011
risk factors, lesions, and vessel information, including preprocedural
and postprocedural stenosis in diseased vessels, procedural information including intracoronary devices, postprocedural complications,
and discharge status. The completeness of the PCIRS database is
maintained by matching the data to the New York State’s hospital
discharge data; the accuracy of the data are ensured by data
validation conducted by the New York State Department of Health’s
review agent.
WHAT IS KNOWN
●
Several earlier studies have identified significantly
higher short-term mortality rates for patients undergoing percutaneous coronary intervention with incomplete revascularization in comparison to patients
who received complete revascularization.
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WHAT THE STUDY ADDS
●
●
This study examined the impact of incomplete revascularization on 8-year mortality after coronary
stenting for multivessel disease.
The results show that the 8-year survival rate was
marginally significantly lower for incomplete as
compared to complete revascularization after coronary stenting for multivessel disease.
The CSRS collects detailed information of all cardiac surgery
procedures performed in New York. Similar to the PCIRS, patient
demographics, preprocedural risk factors, procedural information,
postprocedural complications, and discharge status are recorded in
the CSRS. The CSRS data were used to identify coronary artery
bypass graft (CABG) surgery after index PCI procedures by linking
the two databases using patient identifiers including social security
numbers, dates of birth, admission, procedure, and discharge.
The National Death Index is an index of death records of the
United States maintained by the National Center for Health Statistics.22 It was used to ascertain the vital status of patients after being
discharged from hospitals.
Study Population
We used the PCIRS data to identify patients who had undergone
stenting procedures with BMS in 1999 and 2000 in New York for
this study. The inclusion criteria were (1) patients had multivessel
disease (defined as at least 2 major epicardial arteries with stenosis
ⱖ70%) but no left main coronary artery disease (stenosis ⱖ50%),(2)
had no history of CABG surgery or PCI before the index stenting
procedures,(3) had no myocardial infarction (ST-elevation–myocardial infarction [MI] or non–ST-elevation MI) within 24 hours before
stenting, and (4) had not undergone CABG surgery in the index
admission or within 30 days of discharge. A total of 13 016 patients
were included in this study.
Definition of CR
The completeness of revascularization of stenting was evaluated by
comparing the degrees of stenosis before and after stenting procedures. CR was defined as reduction of stenosis to ⬍50% in all
diseased (ⱖ70% stenosis) lesions in major epicardial coronary
vessels (left anterior descending artery and major diagonals; left
circumflex artery and large marginal branches; and right coronary
artery and right posterior descending artery) in the index hospitalization or within 30 days after discharge from the index hospitalization before having a new MI. When a CR was not achieved during
a stenting procedure, it was defined as a procedure with IR. The
30-day period after discharge was included to enable patients who
were staged to receive CR in another admission shortly after the
index admission to be considered as CR also. However, if they had
an MI before the CR was completed, this was not regarded as CR
because of the occurrence of an adverse event before CR was
attained.
Outcome
The outcome variable is mortality after the index stenting procedure.
Each patient’s vital status was followed until December 31, 2007, by
matching to the National Death Index using social security number,
birth date, and sex. The median length of follow-up (from date of
procedure to the end of 2007) was 8.0 years.
Statistical Analysis
The first step was to examine the differences in the distributions of
baseline patient characteristics such as demographics, preprocedural
risk factors, and diseased vessels between the IR and CR groups.
Pearson ␹2 test was used for categorical variables and the Student t
test for continuous variables.
Then, a logistic (propensity) model was fit by including all
available baseline risk factors as independent variables to predict the
probability of receiving CR (instead of IR). Each CR patient was
then matched to an IR patient on the number of diseased vessels, the
presence of total occlusion, and the value of propensity score
(log-odds of the probability of receiving CR). The matching caliper
for the propensity score was 0.6 standard deviation of its distribution.23–25 The distributions of baseline risk factors between the
matched IR and CR patients were then compared by examining the
standardized differences and performing tests of agreement.26,27
Kaplan-Meier survival curves for the matched IR and CR patients
were compared using a method described by Klein and Moeschberger.28 A Cox proportional hazards model stratifying on the
matched pairs of patients was fit to obtain a hazard ratio to evaluate
the relative risk of death between IR and CR.26,29 A bootstrap 95%
confidence interval for the hazard ratio was also obtained by creating
1000 resamples of the paired-matched patients through random
sampling with replacement.30 In addition, IR was classified into 2
types, namely 1-vessel IR and at least 2-vessel IR, based on the number
of incompletely revascularized vessels. The association between IR and
long-term mortality was examined for each type of IR.
For a group of patient characteristics including age, ejection
fraction, history of MI, congestive heart failure, diabetes, left anterior
descending artery disease, proximal vessel disease, and the presence
of total occlusion were tested, the interactions between IR and such
variables were also tested. For each risk factor, a Cox proportional
hazards model was fit including IR, the risk factor itself, their
interaction term, and other significant (P⬍0.05) risk factors for
mortality identified using a backwards selection.
To evaluate whether the statistical results were sensitive to the
chosen analytical methods, we also compared the risk of death
between the IR and CR groups using the entire unmatched patient
population by adjusting for significant (P⬍0.05) baseline risk factors
identified by a backwards selection approach in Cox proportional
hazards models.
All statistical analyses were conducted in SAS version 9.1 (SAS
Institute, Cary, NC).
Results
Among the 13 016 patients who underwent stenting procedures in 1999 to 2000, CR was achieved in 3803 (29.2%)
patients and IR was obtained in 9213 (70.8%) patients. The
median prevalence of IR across hospitals was 72.5%, and the
interquartile range was 64.9% to 77.5%. The median prevalence of IR across operators was 73.0%, and the interquartile
range was 63.6% to 82.7%.
Table 1 shows that the IR patients were older and more
likely to be Hispanic or black, had lower ejection fraction
Wu et al
Table 1.
Baseline Patient Characteristics of Stenting Patients
Incomplete
Revascularization
(n⫽9213)
Complete
Revascularization
(n⫽3803)
964 (10.5)
502 (13.2)
50–59
1961 (21.3)
955 (25.1)
60–69
2518 (27.3)
1062 (27.9)
70–79
2558 (27.8)
961 (25.3)
80⫹
1212 (13.2)
323 (8.5)
Risk Factor
⬍0.0001
Age, y, n (%)
⬍50
Sex, n (%)
2895 (31.4)
1180 (31.0)
Male
6318 (68.6)
2623 (69.0)
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Non-Hispanic white
7473 (81.1)
3202 (84.2)
Non-Hispanic black
599 (6.5)
193 (5.1)
Hispanic
636 (6.9)
200 (5.3)
Other
505 (5.5)
208 (5.5)
1.99 (0.25)
2.01 (0.25)
18.5–24.99
0.15
780 (8.5)
259 (6.8)
0.001
⬍0.0001
711 (7.7)
187 (4.9)
114 (3.0)
8013 (87.0)
3502 (92.1)
Malignant ventricular
arrhythmia, n (%)
129 (1.4)
48 (1.3)
0.54
Chronic obstructive
pulmonary disease,
n (%)
598 (6.5)
179 (4.7)
⬍0.0001
2504 (27.2)
882 (23.2)
⬍0.0001
Requiring dialysis
107 (1.2)
37 (1.0)
125 (1.4)
26 (0.7)
8981 (97.5)
3740 (98.3)
Diabetes, n (%)
864 (22.7)
No renal failure
1649 (43.4)
1257 (33.1)
⬍20%
304 (3.3)
147 (3.9)
20–29%
316 (3.4)
67 (1.8)
30–39%
804 (8.7)
198 (5.2)
ⱖ40%
7505 (81.5)
3242 (85.2)
Missing
284 (3.1)
149 (3.9)
*Pearson’s exact ␹ test.
⬍0.0001
No. of diseased
vessels, n (%)
2 Diseased vessels
6793 (73.7)
3577 (94.1)
3 Diseased vessels
2420 (26.3)
226 (5.9)
3885 (42.2)
503 (13.2)
⬍0.0001
⬍0.0001
Previous myocardial
infarction, n (%)
1–7 d
2087 (22.7)
883 (23.2)
8–20 d
383 (4.2)
113 (3.0)
ⱖ21 d
1719 (18.7)
412 (10.8)
No myocardial
infarction before
procedure
5024 (54.5)
2395 (63.0)
Cerebrovascular
disease, n (%)
794 (8.6)
204 (5.4)
⬍0.0001
Peripheral arterial
disease, n (%)
612 (6.6)
155 (4.1)
⬍0.0001
9163 (99.5)
3787 (99.6)
41 (0.4)
13 (0.3)
9 (0.1)
3 (0.1)
Hemodynamic state, n (%)
0.003
2
⬍0.0001
Ejection fraction, n (%)
Shock
0.30*
489 (5.3)
2225 (24.2)
3087 (33.5)
Unstable
1 (0.0)
Before this
admission
Creatinine ⬎2.5
mg/dL
3811 (41.4)
P
Value
8 (0.1)
This admission
33 (0.9)
30⫹
Stable
Cardiopulmonary
resuscitation, n (%)
90 (1.0)
25–29.99
Presence of total
occlusion, n (%)
Risk Factor
Complete
Revascularization
(n⫽3803)
Renal failure, n (%)
Body mass index,
kg/m2, n (%)
⬍18.5
Incomplete
Revascularization
(n⫽9213)
None
0.004
415
Continued
Congestive heart
failure, n (%)
⬍0.0001
Race, n (%)
Table 1.
Left ventricular
hypertrophy, n (%)
0.66
Female
Body surface area, m2,
mean (SD)
P
Value
Incomplete Revascularization and Stenting
0.67
(Continued)
values, were more likely to have 3-vessel disease and presence of total occlusion, and were more likely to have histories
of comorbidities such as myocardial infarction, cerebrovascular disease, peripheral arterial disease, left ventricular
hypertrophy, congestive heart failure, chronic obstructive
pulmonary disease, diabetes, and renal failure.
Table 2 shows that the standardized differences in the
prevalence of risk factors between the 3803 pairs of matched
IR and CR patients ranged for 0% to 3.1% in absolute values.
Tests of agreement were all statistically nonsignificant, indicating that the pairs matched well with regards to the risk
factors.
Among the 3803 pairs of matched patients, 817 IR patients
and 731 CR patients died during the postprocedural follow-up
through December 31, 2007, with a median follow-up of 8
years (interquartile range, 7.5– 8.5 years). The risk of death
was 12% higher for IR than CR and was marginally significant (hazard ratio [HR]⫽1.12; 95% confidence interval [CI],
1.01–1.26, P⫽0.04). The 95% bootstrap CI for the HR was
0.98 to 1.32. Figure 1 shows that the respective 8-year
survival rates were 78.5% and 80.8% for IR and CR, and the
difference was statistically significant (P⫽0.04).
When IR was divided into 2 types by the number of
incompletely revascularized vessels, the HRs were 1.11
(P⫽0.08) and 1.20 (P⫽0.22) for 1-vessel IR (n⫽3268) and
multiple-vessel IR (n⫽535), respectively (Table 3). Figure 2
shows that patients with 1-vessel IR had a lower, though
statistically nonsignificant, 8-year survival rate compared
with the matched CR patients (78.8% versus 81.0%,
P⫽0.08). Figure 3 shows that the 8-year survival rates were
416
Circ Cardiovasc Interv
Table 2.
October 2011
Baseline Patient Characteristics of Propensity-Matched Patients
Risk Factor
Incomplete
Revascularization
(n⫽3803)
Complete
Revascularization
(n⫽3803)
506 (13.3)
502 (13.2)
0.3
⫺1.3
Standardized
Difference, %
Age, y, n (%)
⬍50
0.90
50–59
934 (24.6)
955 (25.1)
60–69
1082 (28.5)
1062 (27.9)
1.2
70–79
964 (25.3)
961 (25.3)
0.2
80⫹
317 (8.3)
323 (8.5)
⫺0.6
Sex, n (%)
0.59
Female
1201 (31.6)
1180 (31.0)
1.2
Male
2602 (68.4)
2623 (69.0)
⫺1.2
Non-Hispanic white
3178 (83.6)
3202 (84.2)
⫺1.7
Non-Hispanic black
204 (5.4)
193 (5.1)
1.3
Hispanic
205 (5.4)
200 (5.3)
0.6
Other
216 (5.7)
208 (5.5)
0.9
2.01 (0.26)
2.01 (0.25)
0.8
Race, n (%)
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Body surface area, m2, mean (SD)
0.75
Body mass index, kg/m2, n (%)
⬍18.5
18.5–24.99
36 (0.9)
33 (0.9)
0.8
0.3
868 (22.8)
864 (22.7)
1656 (43.5)
1649 (43.4)
0.4
30⫹
1243 (32.7)
1257 (33.1)
⫺0.8
141 (3.7)
147 (3.9)
⫺0.8
Ejection fraction, n (%)
0.78
20–29%
68 (1.8)
67 (1.8)
0.2
30–39%
209 (5.5)
198 (5.2)
1.3
ⱖ40%
3245 (85.3)
3242 (85.2)
Missing
140 (3.7)
149 (3.9)
0.2
⫺1.2
No. of diseased vessels, n (%)
1.0
2 Diseased vessels
3577 (94.1)
3577 (94.1)
3 Diseased vessels
226 (5.9)
226 (5.9)
0
503 (13.2)
503 (13.2)
0
Presence of total occlusion, n (%)
0.74
0.97
25–29.99
⬍20%
P
Value
0
Previous myocardial infarction, n (%)
1.0
0.31
1–7 d
921 (24.2)
883 (23.2)
2.3
8–20 d
128 (3.4)
113 (3.0)
ⱖ21 d
376 (9.9)
412 (10.8)
⫺3.1
2.3
2378 (62.5)
2395 (63.0)
⫺0.9
Cerebrovascular disease, n (%)
197 (5.2)
204 (5.4)
⫺0.8
0.70
Peripheral arterial disease, n (%)
162 (4.3)
155 (4.1)
0.9
0.67
3787 (99.6)
3787 (99.6)
0
0.87
13 (0.3)
13 (0.3)
0
3 (0.1)
3 (0.1)
0
4 (0.1)
1 (0.0)
3.1
269 (7.1)
259 (6.8)
1.0
No myocardial infarction before procedure
Hemodynamic state, n (%)
Stable
Unstable
Shock
Cardiopulmonary resuscitation, n (%)
Left ventricular hypertrophy, n (%)
Congestive heart failure, n (%)
197 (5.2)
187 (4.9)
Before this admission
134 (3.5)
114 (3.0)
3472 (91.3)
3502 (92.1)
49 (1.3)
48 (1.3)
Malignant ventricular arrhythmia, n (%)
0.65
0.46
This admission
None
0.18
1.2
3.0
⫺2.9
0.2
0.92
(Continued)
Wu et al
Table 2.
Incomplete Revascularization and Stenting
417
Continued
Incomplete
Revascularization
(n⫽3803)
Complete
Revascularization
(n⫽3803)
Chronic obstructive pulmonary disease, n (%)
186 (4.9)
179 (4.7)
Diabetes, n (%)
870 (22.9)
Requiring dialysis
Creatinine ⬎2.5 mg/dL
Risk Factor
Standardized
Difference, %
0.9
0.69
882 (23.2)
⫺0.7
0.73
36 (0.9)
37 (1.0)
⫺0.3
21 (0.6)
26 (0.7)
⫺1.7
3746 (98.5)
3740 (98.3)
Renal failure, n (%)
No renal failure
P
Value
0.36
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76.6% and 79.5% for the patients with multiple-vessel IR and
the matched CR patients, respectively (P⫽0.21).
Table 4 shows that across all subgroups of patients, the
adjusted HRs were greater than 1. For some of the risk
factors, one category was significant (ejection fraction
ⱖ40%, no history of MI, no congestive heart failure, left
anterior descending disease, proximal vessel disease, no total
occlusion), and the other category (eg, ejection fraction
⬍40%) was not. In at least some cases, this was a result of not
enough statistical power. Also none of the interaction terms
between IR and selected risk factors was statistically significant (all probability values ⱖ0.35). Therefore, the results
suggest that the impact of IR on long-term mortality is not
highly dependent on the baseline risk factors in the study.
The sensitivity analysis comparing the survival between IR
and CR in the entire unmatched patient population of 9213 IR
and 3803 CR patients showed that 2564 IR patients and 731
CR patients died during the follow-up period. Adjusting for
baseline risk factors, IR was associated with higher risk of
mortality than CR (adjusted HR⫽1.16; 95% CI, 1.06 –1.26,
P⫽0.001). In addition, a higher risk of mortality for IR was
observed among the patients with 1 incompletely revascularized vessel (adjusted HR⫽1.15; 95% CI, 1.05–1.26,
P⫽0.002) and the patients with multiple incompletely revascularized vessels (adjusted HR⫽1.28; 95% CI, 1.15–1.42,
P⬍0.0001).
1.3
Discussion
In this large population-based study, we examined the impact
of IR on long-term mortality after PCI for patients with
multi-vessel disease in real-world clinical practice. We found
that IR was associated with a 12% increased risk of death
compared with CR for coronary stenting with BMS for
patients with multi-vessel disease during follow-up averaged
8 years (HR⫽1.12; 95% CI, 1.01–1.26, P⫽0.04; 95% bootstrap CI, 0.98 –1.32). We also found that the survival disadvantage associated with IR was not limited to any subgroups
of patients as determined by age, ejection fraction, history of
MI, congestive heart failure, diabetes, left anterior descending
artery disease, proximal vessel disease, or the presence of a
total occlusion. While the increased risk of death was not
statistically significant when the subgroups of 1-vessel IR and
multiple-vessel IR were assessed (HR⫽1.11; P⫽0.08, and
HR⫽1.20, P⫽0.22, respectively), the nonsignificant probability values for each type of IR were likely a result of the loss
of statistical power because the sample size for each type was
smaller than the overall sample size.
The survival disadvantage of IR found in this study with
longer length of follow-up (7–9 years) is relatively consistent
with the results of earlier studies, but somewhat weaker.17,20
For example, an earlier New York study reported that the risk
of death for IR was 15% higher than CR during 3-years of
Figure 1. Kaplan-Meier survival curves for propensity matched-stenting patients.
418
Circ Cardiovasc Interv
October 2011
Table 3. Hazard Ratios (IR and IR Subgroups Versus CR)
for Mortality
Patient Group
No. of
Cases
No. of
Deaths
Hazard Ratio
(95% CI)
P
Value
IR
3803
817
1.12 (1.01, 1.26)
0.04
CR
3803
731
Reference
1 IR vessel
3268
690
1.11 (0.99, 1.25)
0.08
Matched CR patients
3268
625
Multiple IR vessels
535
127
1.20 (0.90, 1.59)
0.22
Matched CR patients
535
106
Subgroups of IR
IR indicates incomplete revascularization; CR, complete revascularization;
and CI, confidence interval.
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follow-up in the BMS era.17 In this study, the difference in
3-year survival rates between IR and CR was not statistically
significant (91.9% versus 92.3%, P⫽0.38). However, our
study found that for the 8-year period examined, the survival
rate for IR was consistently lower than CR and the differences
were statistically significant at years 6 (83.7% versus 85.8%,
P⫽0.04), 7 (80.8% versus 83.4%, P⫽0.02), and 8 (78.5%
versus 80.8%, P⫽0.04). Whether differences of this magnitude (2.3% survival at 8 years) should be cause for changes in
the way PCI is performed is a topic for future debate.
Similarly, other studies with shorter follow-up periods have
found that IR was associated with increased risks of mortality
or MACE.2,13,15,16,18,19,21
It is worth noting that some previous studies have found
that there were no differences between IR and CR in the
incidence of MACE including mortality after PCI in the stent
era.12,14 One possible explanation for these results is that the
sample sizes in these two reports were so small that the
studies did not have the statistical power to show a difference.
For example, Ijsselmuiden et al reported that in a trial that
enrolled 111 IR (culprit vessel revascularization) and 108 CR
patients, MACE (death, myocardial infarction, or repeat
revascularization) rates at 1 year were 32.4% and 26.9% for
IR and CR, respectively, but the difference was not statistically significant (P⫽0.37), probably due to the small sample
size.14 In another study by Mariani et al, the respective 1-year
MACE rates for IR and CR were 11.5% and 11.3% (probability value not significant) in a group that included 159 IR
and 49 CR patients.12 Although the sample size of this study
is quite small, the magnitude of the difference is also small,
so the findings may not be compromised by limited statistical
power.
A few strengths of our study ensure its validity and
generalizability. First, this is a population-based study that
included all eligible patients in New York State in the study
period therefore the results are unlikely to be influenced by
the practice pattern of a few hospitals. Second, the data used
in this study are robust. The data in the PCIRS and CSRS are
rigorously audited to ensure their completeness and accuracy.
Third, the National Death Index was used to ascertain the
vital status of patients so the patients lost to follow up is
minimal. Last, the study evaluated the impact of IR in
real-world practice. Although clinical trials are best at controlling for selection bias and confounding, patients are
usually enrolled in trials based on strict selection criteria;
therefore they are sometimes not representative of the patient
population in real-world practice. In addition, patients in
clinical trials are usually periodically monitored for symptoms, and such monitoring can trigger necessary treatment
that may reduce the incidence of adverse outcomes. Patients
treated in typical clinical practice usually are not monitored
as closely as their counterparts in trials.31
Our study also has limitations. First, because this is an
observational study, treatment selection bias could undermine
the validity of the study. To control for this bias, we
conducted a propensity-matched analysis. Through propensity matching, we were able to balance the distributions of
baseline risk factor between the matched IR and CR groups.
In addition, we conducted a sensitivity analysis using the
unmatched patient population and adjusting for baseline risk
factors, and the results were consistent with that of the
Figure 2. Kaplan-Meier survival curves for
patients with 1-vessel incomplete revascularization (IR) and propensity matched patients
with complete revascularization.
Wu et al
Incomplete Revascularization and Stenting
419
Figure 3. Kaplan-Meier survival curves for
patients with at least multiple-vessel incomplete revascularization (IR) and propensity
matched patients with complete
revascularization.
Downloaded from http://circinterventions.ahajournals.org/ by guest on November 20, 2016
propensity-matched analysis. Nevertheless, risk factors like
lesion length and vessel size were not available in our
databases, and therefore could not be used in the propensity
models. The inability to use these and any other important
Table 4.
missing predictors of adverse outcomes could have introduced a bias in our study.
Second, the definition of IR in this study was determined
by anatomic criteria instead of functional criteria such as
Hazard Ratios (IR Versus CR) for Mortality for Selected Subgroups of Patients
No. of Deaths/
Total Cases
Patient Group
Age
⬍80 y
ⱖ80 y
Ejection fraction
⬍40%
ⱖ40%
History of myocardial infarction
Yes
No
Congestive heart failure
Yes
No
Diabetes
Yes
No
Left anterior descending artery disease
Yes
No
Proximal vessel disease
Yes
No
Total occlusion
Yes
No
8-Year KM
Survival, %
Adjusted* Hazard
Ratio for Death
CR
IR
CR
IR
P Value
Hazard Ratio (95% CI)
P Value
565/3480
166/323
634/3486
183/317
83.8
47.5
81.8
41.8
0.03
0.20
1.12 (1.00, 1.25)
1.23 (0.99, 1.52)
0.06
0.06
136/412
554/3242
142/418
639/3245
66.7
82.8
65.7
80.3
0.66
0.01
1.14 (0.90, 1.45)
1.18 (1.06, 1.33)
0.28
0.004
309/1408
422/2395
341/1425
476/2378
77.9
82.5
76.2
79.8
0.21
0.03
1.12 (0.96, 1.31)
1.19 (1.05, 1.36)
0.15
0.008
164/301
567/3502
165/331
652/3472
45.1
83.8
50.3
81.2
0.34
0.005
1.09 (0.87, 1.36)
1.19 (1.06, 1.33)
0.45
0.003
234/882
497/2921
259/870
558/2933
73.4
83.0
70.5
80.9
0.12
0.05
1.22 (1.02, 1.46)
1.14 (1.01, 1.28)
0.03
0.04
520/2682
211/1121
603/2734
214/1069
80.4
81.6
78.1
79.5
0.01
0.53
1.19 (1.05, 1.33)
1.11 (0.92, 1.34)
0.005
0.29
466/2374
265/1429
466/2064
351/1739
80.3
81.5
77.1
80.1
0.02
0.25
1.21 (1.06, 1.38)
1.10 (0.93, 1.29)
0.004
0.26
93/503
638/3300
108/503
709/3300
81.6
80.6
78.9
78.4
0.22
0.03
1.18 (0.89, 1.55)
1.16 (1.04, 1.29)
0.25
0.006
P Value
for
Interaction
0.45
0.80
0.54
0.50
0.51
0.57
0.35
0.94
IR indicates incomplete revascularization; CR, complete revascularization; and CI, confidence interval.
*In addition to incomplete revascularization, patient group and interaction between incomplete revascularization and patient group, models adjusted for age, race,
body mass index, body surface area, ejection fraction group, number of diseased vessels, cerebrovascular disease, peripheral arterial disease, hemodynamic state,
ECG evidence of left ventricular hypertrophy, congestive heart failure, chronic obstructive pulmonary disease, diabetes, and renal failure.
420
Circ Cardiovasc Interv
October 2011
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fractional flow reserve (FFR) measurements. It has been
reported that FFR guided PCI was associated with significantly lower risk of mortality and myocardial infarction
during a 2-year follow-up when compared with PCI guided
by angiography alone.32,33 Although we had no data on FFR
in our study, it is unlikely that it was used much given the
time frame of our study. The findings of the effectiveness of
FFR31,32 in conjunction with our study findings suggest that
the increased use of FFR could result in more CR and
improved outcomes, although cost-effectiveness would also
have to be assessed.
Third, the study is limited to BMS in the stent group. This
is necessary in order to obtain 8-year follow-up, and there are
many areas in which BMS are used extensively. One report
estimates that in 2007 the proportion of stented lesions treated
with BMS was 25% in the Mayo Clinic in the United States,
but it was as high as 58% in Scotland, United Kingdom, 63%
in Alberta, Canada, and 68% in Belgium.34 Nonetheless, DES
are used more than BMS in many regions, and the results
reported here may not be true for DES. Fourth, to obtain
longer-term results, we had to incorporate data from more
than a decade ago along with more recent data, and stenting
practice and technology have changed considerably since
then. Also, antiplatelet and other pharmacological therapies
have improved significantly. Thus, the relative results for IR
and CR patients may have changed in the interim. Also, in the
subgroup analyses, CR and IR were not matched for baseline
variables. However, the results were risk-adjusted to account
for differences in the baseline variables between CR and IR
patients.
Conclusions
IR may be associated with a higher risk of mortality during
long-term follow-up that after coronary stenting with BMS in
patients with multivessel disease. These findings should be
considered in determining how PCI is performed and in
selecting the most appropriate means of revascularization, for
example, PCI or CABG surgery. Also, more prospective
studies are needed to further test this association.
Acknowledgments
We thank the New York State Cardiac Advisory Committee for their
encouragement and support of this study and Kimberly Cozzens,
Cynthia Johnson, and the cardiac catheterization laboratories of the
participating hospitals for their tireless efforts to ensure the timeliness, completeness, and accuracy of the registry data.
Sources of Funding
This work was supported by the National Institutes of Health
(RC1HL099122).
Disclosures
Dr Jacobs reports serving as a site Principal Investigator for research
projects funded by Abbot Vascular and Accumetrics. Other authors
report that there are no potential conflicts of interest.
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Impact of Incomplete Revascularization on Long-Term Mortality After Coronary Stenting
Chuntao Wu, Anne-Marie Dyer, Spencer B. King III, Gary Walford, David R. Holmes, Jr,
Nicholas J. Stamato, Ferdinand J. Venditti, Samin K. Sharma, Icilma Fergus, Alice K. Jacobs
and Edward L. Hannan
Circ Cardiovasc Interv. 2011;4:413-421; originally published online October 4, 2011;
doi: 10.1161/CIRCINTERVENTIONS.111.963058
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