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Association of chronic obstructive pulmonary disease and mortality following thoracic and complex endovascular aortic repair: a retrospective cohort study

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Association of chronic obstructive pulmonary disease and mortality following thoracic and complex endovascular aortic repair: a retrospective cohort study

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Content Association of Chronic Obstructive Pulmonary Disease and Mortality following Thoracic and
Complex Endovascular Aortic Repair:
A Retrospective Cohort Study
by
Alexander DiBartolomeo
A Thesis presented to the
FAULTY OF THE USC KECK SCHOOL OF MEDICINE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements of the Degree
MASTER OF SCIENCE
(CLINICAL AND BIOMEDICAL INVESTIGATIONS)
May 2024
Copyright 2024 Alexander DiBartolomeo

ii
Dedication
This work is dedicated to my mentors who provided the opportunity, encouragement, and
knowledge that allowed me to pursue a graduate degree.

iii
Acknowledgements
I would like to thank Dr. Vincent Rowe for providing the opportunity and encouragement
to pursue an additional graduate degree as part of my residency program.
I would like to thank Dr. Gregory Magee and Dr. Sukgu Han for their support of my
education, and for their ongoing mentorship in medicine, research, and life.
I would like to thank Dr. Cecilia Patino-Sutton and Dr. Elizabeth Burner for sharing their
dedication to rigorous research and guidance in becoming a clinical researcher.
Lastly, I would like to thank Dr. Hooman Allayee for heading my thesis committee.

iv
TABLE OF CONTENTS
Dedication....................................................................................................................................... ii
Acknowledgements........................................................................................................................iii
List of Tables................................................................................................................................... v
List of Figures................................................................................................................................ vi
Abstract......................................................................................................................................... vii
Chapter One: Introduction .............................................................................................................. 1
Chapter Two: Methods.................................................................................................................... 3
Dataset and study design .......................................................................................... 3
Study population....................................................................................................... 3
Study variables and outcomes.................................................................................. 3
Statistical analysis .................................................................................................... 4
Chapter Three: Results.................................................................................................................... 6
Chapter Four: Discussion.............................................................................................................. 10
Chapter Five: Conclusions............................................................................................................ 15
References..................................................................................................................................... 24

v
List of Tables
Table 1. Patient demographics and characteristics ....................................................................... 16
Table 2. Intraoperative metrics ..................................................................................................... 17
Table 3. Postoperative outcomes................................................................................................... 18
Table 4. Multivariable logistic regression for in-hospital mortality ............................................. 19
Table 5. Multivariable logistic regression for respiratory complications..................................... 20
Table 6. Cox proportional hazards model for 1-year mortality .................................................... 21

vi
List of Figures
Figure 1. Study flow diagram ....................................................................................................... 22
Figure 2. Kaplan-Meier survival curves for 1-year survival probability by COPD group........... 23

vii
Abstract
Objectives
The association between chronic obstructive pulmonary disease (COPD) and complex
endovascular aortic repair (CEVAR) and thoracic aortic endovascular repair (TEVAR) has not
been thoroughly examined. The aim of this study was to assess the association between COPD
severity and postoperative mortality among adults with aortic disease undergoing TEVAR and
CEVAR at institutions that participate in the Society for Vascular Surgery Vascular Quality
Initiative.
Methods
A retrospective cohort study was conducted by querying the SVS VQI database, an
international database established by the SVS to improve the quality, safety, effectiveness and
cost of vascular healthcare, for elective TEVAR and CEVAR cases from 2013-2022. Included
patients were adults that had grafts placed with proximal landing zone ³2 for thoracic,
thoracoabdominal, or complex abdominal aortic disease. Patients were excluded if they
presented with symptomatic disease, ruptured aorta, or required an urgent or emergent surgery.
Patients were stratified by COPD severity based on use of COPD specific medications or
supplementary oxygen at home, in order to identify associations between different severities of
COPD. The primary outcome was in-hospital mortality. Secondary outcomes included
respiratory complications and 1-year mortality. Multivariable logistic regression, adjusted for
patient demographics, operative metrics, and postoperative complications, was used to evaluate
the association between COPD and in-hospital mortality. Assumptions of the model were tested
for and met.
Results

viii
Among 11,336 included participants with TEVAR and CEVAR, 66% did not have COPD,
9% had COPD not on medications, 20% had COPD on medications, and 6% had COPD on home
supplemental oxygen. Patients with increasing severity of COPD were increasingly older (no
COPD 69.1, COPD without medications 71.9, COPD on medications 71.7, COPD home
supplemental oxygen 73.0 years old), had an increasing proportion of females (31%, 37%, 37%,
46%), and an increasing proportion of white race reported (72%, 81%, 82%, 84%). In-hospital
mortality was 2.3%, 3.7%, 3.2%, and 4.5% (P=.0004) respectively, and was not associated with
increased odds of mortality in the multivariable analysis. Respiratory complications occurred in
4.3%, 4.5%, 6.4%, and 7.3% (P<.0001) and was associated with increased odds for COPD on
medications (OR 1.3, [95% CI 1.0-1.7]) and COPD on home supplemental oxygen (OR 1.7 [1.1-
2.6]). 1-year survival was 91%, 87%, 86%, and 80% and associated with increased risk for each
COPD group (COPD without medications HR 1.4 [1.1-1.8], COPD on medications HR 1.4 [1.2-
1.7], COPD home supplemental oxygen HR 1.9[1.5-2.4]).
Conclusions
Among patients undergoing TEVAR and CEVAR, those with COPD vs no COPD have
increased rates of in-hospital mortality, respiratory complications, and 1-year mortality. Among
those with COPD, increased COPD severity is independently associated with increased
respiratory complications and 1-year mortality, which should be factored into clinical decision
making prior to performing elective TEVAR and CEVAR in this patient population.

1
Chapter One: Introduction
Chronic obstructive pulmonary disease (COPD) is characterized by chronic respiratory
symptoms due to abnormalities of the airways and/or alveoli that cause airflow obstruction
among adults. 1 COPD is a known risk factor for a variety of complications after many types of
surgeries, 2 and is associated with respiratory complications and mortality among patients with
aortic disease. 3 For patients who require an aortic repair, COPD may be a more concerning risk
factor during open surgical repairs that require a thoracotomy, due to the physiologic changes
that alter respiratory mechanics.
The development of endovascular technology has been a major turning point for
decreasing the morbidity and mortality of thoracic and thoracoabdominal aortic repairs and a
readily available alternative for patients who are deemed too high risk for open surgical repair. 4
Diseases of the thoracic and thoracoabdominal aorta can now be treated with thoracic
endovascular aortic repair (TEVAR) and complex or fenestrated-branched endovascular aortic
repair (CEVAR). Although an endovascular repair removes many of the physiologic changes of
breathing that are altered with a thoracotomy, whether this decreases the risk of complications
for patients with COPD is unknown. Studies of the risk factors associated with mortality in
patients undergoing TEVAR and CEVAR have identified COPD as one of the factors that
increase the likelihood of postoperative mortality, 5,6 but evidence of the direct association of
COPD with TEVAR and CEVAR are currently lacking. Previous studies have examined the
association of COPD and infrarenal endovascular aortic repair (EVAR), which have
demonstrated increased risk for mortality and respiratory complications, particularly for patients
that are dependent on supplemental oxygen or have the most severe classification of COPD. 7-9

2
Therefore, there were three aims of this study regarding adult patients undergoing
TEVAR and CEVAR in at institutions participating in the Society for Vascular Surgery Vascular
Quality Initiative (SVS VQI) between 2013-2022. Firstly, we aimed to evaluate the independent
association between patients without COPD and each severity of COPD for in-hospital mortality.
Secondly, to evaluate the independent association between patients without COPD and each
severity of COPD for postoperative respiratory complications. And lastly, to evaluate the
independent association between patients without COPD and each severity of COPD for 1-year
mortality. We hypothesized that increasing severity of COPD compared to patients without
COPD is associated with increased in-hospital mortality, postoperative respiratory complications,
and 1-year mortality.

3
Chapter Two: Methods
Dataset and study design
The SVS VQI Thoracic and Complex Endovascular Aortic Repair registry was used to
conduct a retrospective, observational cohort study of patients that underwent TEVAR or
CEVAR between 2013-2022. 10 The SVS VQI is an international vascular surgery registry with
more than 1,000 participating centers in the United States, Canada, and Singapore that collects
and exchanges information among regional quality groups to improve the quality, safety,
effectiveness and cost of vascular healthcare. Use of the registry for this study was approved by
the SVS VQI Research Advisory Committee. Institutional Review Board approval and patient
informed consent were waived due to the de-identified nature of the SVS VQI. This study was
reported following the STROBE reporting guidelines. 11
Study population
Patients were included in the study if they were >18 years old, underwent an aortic
endograft implantation with proximal landing zone ³ 2 for an aortic pathology of degenerative
aneurysm, chronic post-dissection aneurysm, dissection, or penetrating aortic ulcer (PAU).
Patients were excluded if they presented with a symptomatic or ruptured aorta, had an urgent or
emergent procedure, or had missing data for the COPD and in-hospital mortality variables. Inhospital and 1-year follow-up data is provided in the SVS VQI registry.
Study variables and outcomes
The primary exposure variable was COPD severity. The COPD SVS VQI variable
included patients without COPD, with COPD who are not taking COPD medications, with
COPD who are taking COPD medications, and those with COPD who require home
supplemental oxygen therapy. Participants were categorized into four cohorts based on a

4
diagnosis and severity of COPD. The primary outcome was postoperative in-hospital mortality.
Secondary outcomes included 1-year mortality and respiratory complications. In the SVS VQI,
respiratory complications are defined as postoperative pneumonia, reintubation, or both.
Multivariable models were used to address potential confounders related to mortality and
respiratory complications.
Statistical analysis
Categorical data was reported with frequencies and percent. Continuous data that was
normally distributed was reported as a mean ± standard deviation. Continuous non-normally
distributed data was reported as a median with interquartile range. Categorical data was analyzed
using the c2 test. Continuous data was analyzed using the ANOVA F-test or the Kruskal-Wallis
test. Univariate analysis was performed to evaluate the relationship between the exposure and
outcome variables. Survival curves were created using Kaplan-Meier estimates and log-rank test
was used to compare 1-year survival between the cohorts.
Multivariable logistic regression was performed to evaluate the association of COPD
with in-hospital mortality adjusted for confounding. As most exposure variables analyzed with
univariate analysis demonstrated statistical significance, covariates for the model were chosen
based on expert opinion and literature review of clinical significance for in-hospital mortality
following TEVAR and CEVAR. As there were 310 events for the primary outcome of in-hospital
mortality, a maximum of 30 variables were considered for use in the multivariable model. The
covariates that were considered as confounders and included in the model included age,
respiratory complications, aortic pathology, sex, race, body mass index, prior stroke, coronary
artery disease, congestive heart failure, diabetes mellitus, hypertension, preoperative
hemoglobin, preoperative glomerular filtration rate, preoperative antiplatelet use, preoperative

5
anticoagulation use, type of repair, American Society of Anesthesiologists classification,
intraoperative blood transfusion, time to extubation, length of hospital stay, postoperative
myocardial infarction, postoperative congestive heart failure, postoperative stroke, postoperative
dialysis, and spinal cord ischemia. The covariates considered to be effect modifiers included
procedure time and estimated blood loss. Although the variance inflation factor for preoperative
smoking was only 1.04, smoking was not included in the multivariable model due to the clinical
correlation with COPD. Covariates that did not demonstrate statistical significance of P < 0.05
were removed from consideration for the multivariable model. Variables that were maintained in
the multivariable model due to their clinical significance, regardless of their statistical
significance, included COPD severity, age, respiratory complications, and aortic pathology.
A secondary analysis was completed using Cox proportional hazards to evaluate the
association with COPD and 1-year mortality, using the same covariates included in the model for
in-hospital mortality. An additional secondary analysis was completed using multivariable
logistic regression to evaluate the association of COPD with respiratory complications, using the
same covariates included in the in-hospital mortality model. Missing data was excluded from the
multivariable model analyses. Assumptions of the multivariable logistic regression and Cox
proportional hazards models were checked and met. Statistical significance was set at P<0.05
with two-sided tests. All statistical analysis was performed using SAS 9.4 (SAS Institute Inc.,
Cary, NC, USA).

6
Chapter Three: Results
There were 22,521 cases in the SVS VQI registry of which 15,201 were eligible for
inclusion. After exclusions, 11,336 remained for analysis in the study. There were 9 patients
excluded for having missing COPD or mortality status. The study flow diagram can be seen in
Figure 1. There were 7,472 in the no COPD group, 998 in the COPD without medications group,
2,228 in the COPD on medications group, and 638 in the COPD on home supplemental oxygen
group. Patients with increasing severity of COPD were increasingly older (no COPD 69.1,
COPD without medications 71.9, COPD on medications 71.7, COPD home supplemental oxygen
73.0 years old), had an increasing proportion of females (31%, 37%, 37%, 46%), and an
increasing proportion of white race reported (72%, 81%, 82%, 84%). A similar pattern followed
several comorbidities including an increasing history of stroke (11%, 13%, 13%, 17%),
increasing history of coronary artery disease symptoms (20%, 27%, 28%, 33%), increasing
history of congestive heart failure (11%, 17%, 20%, 29%), increasing history of diabetes (16%,
16%, 19%, 25%), increasing use of antiplatelet and anticoagulation medications, and increasing
proportion of degenerative aneurysmal disease (65%, 82%, 81%, 84%). Nearly all patients were
American Society of Anesthesiologists class 3 or 4 with a generally increasing proportion of
class 4 patients with increasing severity of COPD (42%, 51%, 49%, 63%). The groups with
COPD had a higher rate of smoking history than the group without COPD (73%, 94%, 93%,
93%). The COPD on home supplemental oxygen group also had the highest median body mass
index (27.4, 26.2, 26.8, 27.8), highest rate of dialysis (2.5%, 1.5%, 2.0%, 3.0%), and largest
mean max aortic diameter (56, 58, 58, 59 mm). Further patient demographics and characteristics
can be seen in Table I.

7
All intraoperative metrics other than use of iodinated contrast (P=.453) demonstrated a
significant difference between groups on univariate analysis. The COPD on home supplemental
oxygen group had the lowest utilization of general anesthesia (98%, 99%, 98%, 95%, P=.0019).
With increasing severity of COPD there was an increasing length of median procedure time (160,
180, 183, 187 minutes, P<.0001), increasing length of median fluoroscopy time (27.6, 38.5, 38.1,
42.0 minutes, P<.0001), and decreasing preoperative cerebrospinal fluid drain placement (33%,
33%, 29%, 26%, P=.0027). Median estimated blood loss (150, 200, 200, 200 mL) and median
number of units of blood transfusion (0, 0, 0, 0) were clinically similar between groups.
For the primary outcome, the rate of in-hospital mortality was 2.3% for the no COPD
group, 3.7% for the COPD without medications group, 3.2% for the COPD on medications
group, and 4.5% for the COPD on home supplemental oxygen group (P=.0004). The proportion
of patients that were extubated in the operating room decreased with increasing severity of
COPD (89%, 88%, 86%, 79%, P<.0001) but the median number of days intubated was similar
between the groups (4, 3, 3, 3, P=.8217). The rate of respiratory complications was statistically
significantly different between groups at 4.3%, 4.5%, 6.3%, and 7.4%, respectively (P<.0001).
Postoperative complications were more common in patients with COPD (16%, 20%, 21%, 21%,
P<.0001), including congestive heart failure (1.1%, 1.4%, 1.8%, 1.4%, P=.0477), spinal cord
ischemia (1.1%, 2.2%, 2.0%, 1.6%, P=.0006), lower mean glomerular filtration rate (69.1, 65.1,
64.7, 64.4, P<.0001), and postoperative dialysis (1.3%, 2.2%, 2.6%, 2.0%, P=.0004). Myocardial
infarction, intestinal ischemia, and stroke demonstrated statistical difference between the groups
but without a clear pattern. The median intensive care unit stay was the same for all groups (2
days) while median total hospital length of stay was longest in the COPD on home supplemental
oxygen group (4, 4, 4, 5 days, P=.0026). Postoperative outcomes are detailed in Table III. The

8
one-year survival was 91% for the no COPD group, 87% for COPD without medications, 86%
for COPD on medications, and 80% for COPD on home supplemental oxygen. The logrank pvalue for survival probability was <.0001. The Kaplan-Meier survival curves are shown in
Figure 2.
In the multivariable analysis for in-hospital mortality, none of the COPD severity groups
were associated with an increased risk of mortality compared to the group without COPD
(COPD without medications: OR 1.3 [95% CI 0.78 – 2.28, P=0.29]; COPD on medications: OR
0.91 [95% CI 0.59 – 1.42, P=0.69]; COPD home supplemental oxygen: OR 1.34 [95% CI 0.72 –
2.48, P=0.36]). Multiple postoperative complications did demonstrate an increased risk of inhospital mortality on the multivariable model. Those with the largest effect size were respiratory
complications, which demonstrated 9 times increased odds compared to no complications (OR
9.4 [95% CI 6.30 – 13.97, P<.0001]), and time to extubation >24 hours, which demonstrated 7
times increased odds compared to extubation in the operating room (OR 7.0 [95% CI 4.20 –
11.63, P<.0001]). Older age, intraoperative blood transfusion, myocardial infarction, stroke,
spinal cord ischemia, and postoperative dialysis also showed increased odds of in-hospital
mortality (Table IV).
In the multivariable model for respiratory complications, there was an increased odds for
patients with COPD on medications (OR 1.3 [95% CI 1.01 – 1.72, P=.044]) and for patients with
COPD on home supplemental oxygen (OR 1.7 [95% CI 1.07 – 2.58, P=.022]) compared to
patients without COPD. New postoperative dialysis resulted in the greatest increased risk of
respiratory complications at 12 times increased odds compared to no dialysis (OR 12.0 [95% CI
7.44 – 19.34, P<.0001]). A nearly 7 times increased odds was seen in patients with postoperative

9
congestive heart failure (OR 6.6 [95% CI 3.98 – 11.01, P<.0001]) and postoperative stroke (OR
6.8 [95% CI 4.31 – 10.76]) (Table V).
All three COPD groups were associated with increased risk of 1-year mortality compared
to the group without COPD in the multivariable model, with the COPD on home supplemental
oxygen group demonstrating the largest effect size (COPD without medications: HR 1.4 [95% CI
1.13 – 1.78, P=.0028]; COPD on medications: HR 1.4 [95% CI 1.18 – 1.66, P<.0001]; COPD
home supplemental oxygen: HR 1.9 [95% CI 1.46 – 2.42, P<.0001]). Several postoperative
complications were associated with an increased risk of 1-year mortality including respiratory
complications (HR 2.8 [95% CI 2.29 – 3.43, P<.0001]), myocardial infarction (HR 2.5 [95% CI
1.95 – 3.21, P<.0001]), spinal cord ischemia present at discharge (HR 1.89 [95% CI 1.40 – 2.55,
P<.0001]), and new postoperative dialysis (HR 2.4 [95% CI 1.88 – 3.13, P<.0001]) (Table IV).

10
Chapter Four: Discussion
This study evaluated the impact of COPD severity on postoperative mortality and respiratory
complications following TEVAR and CEVAR using a retrospective cohort study of the SVS
VQI. The incidence of in-hospital mortality was increased for all patients with COPD compared
to those without COPD, although multivariable analysis did not demonstrate increased odds of
in-hospital mortality after adjustment for covariates. Respiratory complications occurred more
frequently for patients with COPD and was associated with an increase in risk on multivariable
analysis. One-year survival for patients with COPD was lower than patients without COPD and
was independently associated with increased risk for all COPD groups.
These findings are similar to studies completed to evaluate the association of COPD and
infrarenal EVAR, that show the same pattern of worse outcomes with increasing severity of
COPD for in-hospital mortality, respiratory complications, and long-term mortality when the use
of medications and supplemental oxygen dependence is used for patient stratification,. 8,9,12 This
study demonstrated a rate of in-hospital mortality of 4.5% for supplemental oxygen dependent
patients compared to 2.3% for patients without COPD and pulmonary complications of 7.4% and
4.3%, respectively. Similarly, Stone et al. showed a rate of in-hospital mortality twice that for
patients with COPD on home supplemental oxygen compared to patients without COPD (2% vs
1%) and an even greater difference in the rate of pulmonary complications (10.4% vs 4.3%)
following EVAR.
Presumably, the difference in mortality for patients with COPD may be attributed to
differences in respiratory complications and pulmonary failure, which is supported in this study
by the odds ratio of in-hospital mortality of 9.4 for patients with respiratory complications
compared to those without. The mechanisms that have been attributed to respiratory

11
complications for patients undergoing open surgical repairs include alterations in respiratory
mechanics after a thoracotomy, reduction in lung volume and diaphragm activity with anesthesia,
need for division of the diaphragm, postoperative hypoxemia, and pain. 13-15 Several of these
mechanisms may not be present after an endovascular repair, but effects of anesthesia and
immobility persist. Patients with COPD, particularly if they are dependent on supplemental
oxygen therapy, may not have the pulmonary reserve to overcome these respiratory stressors and
are more susceptible to respiratory complications even with an endovascular repair.
Patients with COPD who are dependent on supplemental oxygen were a specific
population we were interested in as this is an easily identifiable clinical finding of a patient with
advanced respiratory disease who will likely receive additional preoperative diagnostics and
discussion of the risk versus benefit of repair. Although administration of supplemental oxygen
has been shown to increase survival for patients with severe chronic resting arterial hypoxemia,
their life expectancy remains reduced with a 1-year survival rate of approximately 75-81%, 2
year survival of 51-67%, and 5 year survival of 19-35%.
16-18 The 1-year survival of 80% for
patients on home supplemental oxygen in our study matches these previously described survival
rates, although the patients in this study represent only the patients who were deemed fit enough
for surgery despite their dependence on supplemental oxygen, and one could surmise that
patients on supplemental oxygen who were not offered an operation may have had worse
survival outcomes. The increased risk of mortality in these patients compared to the general
population and the increased risk of respiratory complications and 1-year mortality suggest that
additional thought should be given to the risk versus benefit evaluation for treatment of their
aortic disease. As only elective cases were evaluated in this study, a discussion of risk versus
benefit is expected to have been had with the patient prior to undergoing repair. Most of the

12
patients underwent aortic repair for aneurysmal disease where the risk of rupture can be
compared, but the remaining patients underwent repair for dissection and PAU in which the
criteria for benefit for repair is not as well known. For patients with supplemental oxygen
dependent COPD, a perioperative mortality twice that of patients without COPD and a one-year
mortality rate 11% greater than patients without COPD needs to be weighed against the
estimated annual risk of rupture. Although data regarding the risk of rupture and death for
thoracic aortic aneurysms is limited, the risk of an aortic event at 1 year for aneurysms of 5.5 cm
has been demonstrated at 7.2%, for aneurysms of 6.0 at 9.3%, and aneurysms of 7.0 at 15.4%.19
Current guidelines recommend repair of a thoracic aneurysm ³5.5 cm and thoracoabdominal
aortic aneurysms ³6.0 cm, due to their higher risk of repair. 20 Just as the threshold for
thoracoabdominal aortic aneurysms is higher than abdominal aortic aneurysms and thoracic
aortic aneurysms because the risk of repair is higher, patients with COPD, especially those who
are dependent on supplemental oxygen, should probably have a higher threshold for elective
repair given the increased associated risks. This does need to be balanced against prior evidence
suggesting that patients with COPD may experience aortic rupture at smaller sizes than the rest
of the population, although severity of COPD was not considered in these reports. 21
Alternatively, survival may not always mean a successful surgical outcome if it is not
accompanied by a reasonable quality of life. For example, although not captured in the SVS
VQI, respiratory complications increase the likelihood of need for a tracheostomy, which is a life
altering complication. Patients with COPD also demonstrated an increased rate of non-home
discharge, indicating a more difficult and likely prolonged returned to baseline, if they can make
a recovery at all. We believe that the generalizability of these results to patients with COPD and

13
thoracic or thoracoabdominal aortic aneurysms in North America is good, given the variety and
number of centers that contribute patient data to the SVS VQI in the United States and Canada.
There are several limitations to this study. The standard method for stratifying patients
with COPD for research studies follows recommendations of the Global Initiative for Chronic
Obstructive Lung Disease (GOLD) report. The most recent GOLD report recommends
classifying patients based on airflow limitation from spirometry results, history of exacerbations,
and current symptoms scored on validated questionnaires. 1 This information is not available for
many vascular patients at the time of surgery in a retrospective study and is not data collected by
the SVS VQI. Therefore, our use of COPD medications and supplemental home oxygen status,
which is collected in the SVS VQI, was a practical substitution. Although this classification has
not been validated to describe outcomes in this population, it has been utilized in previous
vascular surgery research. 8,9 The retrospective study design creates selection bias as the decision
for which patients would undergo repair was not standardized. Although patients with COPD on
supplemental home oxygen had the highest prevalence of comorbidities, these patients were
considered fit enough for surgery, therefore, the risk of mortality for all patients with COPD that
would undergo a CEVAR or TEVAR would likely be higher than described here. The SVS VQI
is a large, de-identified database and collection of additional data is not possible, which prevents
improvement of internal validity and contains center and physician specific practice patterns that
are not consistently applied to all patients.
Patients with COPD, particularly those who are dependent on supplemental oxygen,
experience a higher rate of postoperative morbidity and mortality following TEVAR and
CEVAR. High-risk patients such as these may not derive a benefit from aortic repair at the same
criteria as the general population of patients with thoracic and thoracoabdominal aortic disease.

14
Additional research will be required to identify the best criteria for repair in high-risk patients. In
the meantime the current information available should be used during preoperative risk and
benefit discussions for optimal joint decision making.

15
Chapter Five: Conclusions
Patients with COPD have increased rates of in-hospital mortality, respiratory
complications, and 1-year mortality after TEVAR and CEVAR. COPD severity is independently
associated with increased respiratory complications and 1-year mortality. These results should be
weighed in the risk and benefit evaluation of patients with COPD being considered for TEVAR
or CEVAR.

16
Table I. Patient demographics and characteristics
No COPD
(N=7472)
Not treated
(N=998)
On meds
(N=2228)
Home oxygen
(N=638)
Total
(N=11336)
P-value
Age 69.1 (12.10) 71.9 (8.62) 71.7 (8.39) 73.0 (7.37) 70.1 (11.04) <.0001
Sex (Male) 5157 (69.0%) 630 (63.2%) 1396 (62.7%) 346 (54.2%) 7529 (66.4%) <.0001
Race <.0001
White 5392 (72.2%) 811 (81.3%) 1828 (82.0%) 536 (84.0%) 8567 (75.6%)
Black 1301 (17.4%) 113 (11.3%) 270 (12.1%) 57 (8.9%) 1741 (15.4%)
Other 778 (10.4%) 74 (7.4%) 130 (5.8%) 45 (7.1%) 1027 (9.1%)
Ethnicity <.0001
Hispanic 407 (5.5%) 26 (2.6%) 65 (2.9%) 26 (4.1%) 524 (4.6%)
BMI (median) 27.4 26.2 26.8 27.8 27.2 <.0001
Prior stroke 809 (10.8%) 133 (13.3%) 297 (13.3%) 107 (16.8%) 1346 (11.9%) <.0001
CAD symptoms 1479 (19.8%) 270 (27.1%) 626 (28.1%) 209 (32.8%) 2584 (22.8%) <.0001
Congestive heart
failure
844 (11.3%) 168 (16.8%) 454 (20.4%) 186 (29.2%) 1652 (14.6%) <.0001
Diabetes 1179 (15.8%) 163 (16.3%) 427 (19.2%) 157 (24.6%) 1926 (17.0%) <.0001
Hypertension 6672 (89.3%) 923 (92.5%) 2035 (91.3%) 577 (90.4%) 10207
(90.0%)
.0052
Dialysis 189 (2.5%) 15 (1.5%) 44 (2.0%) 19 (3.0%) 267 (2.4%) .23
Smoking history 5453 (73.0%) 939 (94.1%) 2072 (93.0%) 590 (92.5%) 9054 (79.9%) <.0001
Hemoglobin 12.5 (2.05) 12.8 (2.05) 12.8 (2.08) 12.6 (2.13) 12.6 (2.06) <.0001
Creatinine 1.1 (0.64) 1.2 (0.69) 1.2 (0.79) 1.1 (0.38) 1.2 (0.67) .0031
eGFR 74.6 (27.07) 71.5 (26.83) 70.7 (26.64) 72.2 (26.09) 73.4 (26.96) <.0001
Aspirin 4565 (61.1%) 647 (64.8%) 1435 (64.4%) 405 (63.5%) 7052 (62.2%) .0329
P2Y12
antagonist
805 (10.8%) 135 (13.5%) 317 (14.2%) 102 (16.0%) 1359 (12.0%) <.0001
Anticoagulation 985 (13.2%) 143 (14.3%) 349 (15.7%) 120 (18.8%) 1597 (14.1%) .0003
Ejection fraction <.0001
<30% 134 (1.8%) 21 (2.1%) 51 (2.3%) 10 (1.6%) 216 (1.9%)
30-50% 765 (10.2%) 129 (12.9%) 315 (14.1%) 83 (13.0%) 1292 (11.4%)
>50% 4458 (59.7%) 575 (57.6%) 1294 (58.1%) 359 (56.3%) 6686 (59.0%)
ASA class <.0001
1 19 (0.3%) 0 (0.0%) 3 (0.1%) 0 (0.0%) 22 (0.2%)
2 185 (2.5%) 8 (0.8%) 22 (1.0%) 3 (0.5%) 218 (1.9%)
3 4076 (54.7%) 483 (48.6%) 1108 (49.8%) 231 (36.3%) 5898 (52.1%)
4 3162 (42.4%) 502 (50.5%) 1090 (49.0%) 399 (62.7%) 5153 (45.6%)
5 13 (0.2%) 1 (0.1%) 3 (0.1%) 3 (0.5%) 20 (0.2%)
Prior aortic
aneurysm repair
1719 (23.0%) 255 (25.6%) 554 (24.9%) 163 (25.5%) 2691 (23.7%) .30
Maximum aortic
diameter
56.0 (13.73) 58.3 (12.47) 57.9 (12.23) 59.3 (12.12) 56.8 (13.29) <.0001
Pathology <.0001
Aneurysm 4851 (64.9%) 818 (82.0%) 1808 (81.1%) 536 (84.0%) 8013 (70.7%)
Dissection 1597 (21.4%) 95 (9.5%) 189 (8.5%) 46 (7.2%) 1927 (17.0%)
Aneurysm
from
dissection
636 (8.5%) 34 (3.4%) 97 (4.4%) 26 (4.1%) 793 (7.0%)
PAU 388 (5.2%) 51 (5.1%) 134 (6.0%) 30 (4.7%) 603 (5.3%)
Type of repair .0002
Complex
EVAR
4811 (64.4%) 691 (69.2%) 1502 (67.4%) 448 (70.2%) 7452 (65.7%)
TEVAR 2661 (35.6%) 307 (30.8%) 726 (32.6%) 190 (29.8%) 3884 (34.3%)

17
Table II. Intraoperative metrics
No COPD
(N=7472)
Not treated
(N=998)
On meds
(N=2228)
Home oxygen
(N=638)
Total
(N=11336)
P-value
Anesthesia
type
0.0019
Local 120 (1.6%) 10 (1.0%) 40 (1.8%) 21 (3.3%) 191 (1.7%)
Regional 40 (0.5%) 3 (0.3%) 10 (0.4%) 8 (1.3%) 61 (0.5%)
General 7309 (97.9%) 985 (98.7%) 2177 (97.8%) 609 (95.5%) 11080 (97.8%)
Total
procedure
time (median)
160 180 183 187 169 <.0001
Iodinated
contrast
100 100 100 100 100 0.45
Fluoroscopy
time
27.6 38.5 38.1 42 31.2 <.0001
EBL 150 200 200 200 150 <.0001
Blood
transfusion
0 0 0 0 0 <.0001
Spinal drain 0.0027
Pre-op 2444 (32.7%) 326 (32.7%) 652 (29.3%) 167 (26.2%) 3589 (31.7%)
Post-op 166 (2.2%) 25 (2.5%) 47 (2.1%) 14 (2.2%) 252 (2.2%)

18
Table III. Postoperative outcomes
No COPD
(N=7472)
Not treated
(N=998)
On meds
(N=2228)
Home oxygen
(N=638)
Total
(N=11336)
P-value
In-hospital
mortality
173 (2.3%) 37 (3.7%) 71 (3.2%) 29 (4.5%) 310 (2.7%) 0.0004
Respiratory <.0001
Pneumonia 62 (0.8%) 9 (0.9%) 35 (1.6%) 11 (1.7%) 117 (1.0%)
Reintubation 216 (2.9%) 27 (2.7%) 84 (3.8%) 23 (3.6%) 350 (3.1%)
Both 46 (0.6%) 9 (0.9%) 22 (1.0%) 13 (2.0%) 90 (0.8%)
Time to
extubation
<.0001
OR 6488 (89.1%) 865 (88.1%) 1865 (86.1%) 483 (79.4%) 9701 (87.9%)
<12 hrs 403 (5.5%) 50 (5.1%) 141 (6.5%) 73 (12.0%) 667 (6.0%)
12-24 hrs 197 (2.7%) 36 (3.7%) 93 (4.3%) 33 (5.4%) 359 (3.3%)
> 24 hrs 196 (2.7%) 31 (3.2%) 67 (3.1%) 19 (3.1%) 313 (2.8%)
Days intubated 4 3 3 3 3 0.82
ICU stay, days 2 2 2 2 2 0.10
Total LOS,
days
4 4 4 5 4 0.0026
Highest
creatinine
1.4 (1.34) 1.4 (1.15) 1.5 (1.25) 1.4 (1.17) 1.4 (1.30) 0.82
Postop eGFR 69.1 (30.02) 65.1 (29.90) 64.7 (29.45) 64.4 (29.43) 67.6 (29.93) <.0001
Postop
complications
1223 (16.4%) 197 (19.7%) 465 (20.9%) 133 (20.8%) 2018 (17.8%) <.0001
Myocardial
infarction
138 (1.8%) 28 (2.8%) 49 (2.2%) 12 (1.9%) 227 (2.0%) 0.0083
CHF 84 (1.1%) 14 (1.4%) 39 (1.8%) 9 (1.4%) 146 (1.3%) 0.0477
Dysrhythmia 398 (5.3%) 56 (5.6%) 143 (6.4%) 33 (5.2%) 630 (5.6%) 0.11
Stroke 154 (2.1%) 27 (2.7%) 42 (1.9%) 14 (2.2%) 237 (2.1%) 0.0002
Spinal cord
ischemia
0.0006
Transient 94 (1.3%) 23 (2.3%) 31 (1.4%) 8 (1.3%) 156 (1.4%)
Present at
discharge
80 (1.1%) 22 (2.2%) 44 (2.0%) 10 (1.6%) 156 (1.4%)
Postop dialysis,
n (%)
99 (1.3%) 22 (2.2%) 58 (2.6%) 13 (2.0%) 192 (1.7%) 0.0004
Intestinal
ischemia
<.0001
Medical 32 (0.4%) 7 (0.7%) 24 (1.1%) 11 (1.7%) 74 (0.7%)
Surgical 47 (0.6%) 15 (1.5%) 22 (1.0%) 4 (0.6%) 88 (0.8%)
Re-operation 0.07
Related 334 (4.5%) 59 (5.9%) 125 (5.6%) 35 (5.5%) 553 (4.9%)
Not related 91 (1.2%) 19 (1.9%) 30 (1.3%) 10 (1.6%) 150 (1.3%)
Discharged
home
6471 (86.6%) 835 (83.7%) 1790 (80.3%) 499 (78.2%) 9595 (84.6%) <.0001

19
Table IV. Multivariable logistic regression for in-hospital mortality
Variable OR 95% CI p-value
COPD No COPD Ref
Not treated 1.33459 0.78071 2.2814 0.29
On meds 0.91334 0.58909 1.4161 0.69
Home Oxygen 1.33755 0.72077 2.4821 0.36
Age <=60 Ref
61-70 2.06514 0.99809 4.273 0.051
71-80 2.50514 1.23538 5.08 0.0109
>80 2.98728 1.38524 6.4421 0.00525
Respiratory
complications
Yes 9.38477 6.30428 13.9705 <0.0001
No Ref
Pathology Aneurysm Ref
Dissection 0.7557 0.40264 1.4184 0.38
Aneurysm from
dissection 0.94668 0.40047 2.2379 0.90
PAU 0.73415 0.32312 1.6681 0.46
Preop GFR <30 1.44237 0.69412 2.9972 0.33
30-45 1.11932 0.64338 1.9473 0.69
45-60 0.73904 0.4396 1.2425 0.25
60-90 0.71257 0.45695 1.1112 0.13
>=90 Ref
Intra op transfusion Yes 2.58719 1.75656 3.8106 <0.0001
No Ref
Time to extubation OR Ref
<12 hrs 1.1842 0.62445 2.2457 0.60
12-24 hrs 2.08083 1.12024 3.8651 0.02038
> 24 hrs 6.98692 4.19766 11.6296 <0.0001
Post op MI Yes 5.8805 3.47295 9.957 <0.0001
No Ref
Stroke Yes 3.70379 2.14473 6.3962 <0.0001
No Ref
Spinal cord ischemia, n
(%)
None Ref
Transient 1.00108 0.34958 2.8668 0.99
Present at discharge 2.73102 1.32673 5.6217 0.00638
Post op dialysis Yes 4.21356 2.40662 7.3772 <0.0001
No Ref
ASA class 1-3 Ref
4-5 1.3825 0.9749 1.9605 0.069

20
Table V. Multivariable logistic regression for respiratory complications
Variable OR 95% CI p-value
COPD No COPD Ref
Not treated 0.7652 0.50085 1.1692 0.22
On meds 1.3176 1.00688 1.7243 0.04444
Home Oxygen 1.6636 1.07454 2.5757 0.02247
Age <=60 Ref
61-70 0.8557 0.60884 1.2027 0.37
71-80 0.8099 0.57111 1.1485 0.24
>80 0.9309 0.62055 1.3964 0.73
Pathology Aneurysm Ref
Dissection 1.4288 1.0407 1.9616 0.02734
Aneurysm from
dissection 1.0617 0.67041 1.6815 0.80
PAU 1.6435 1.04125 2.5942 0.03288
BMI <18 1.7161 0.96508 3.0517 0.07
18-24.9 Ref
25-29.9 0.745 0.5697 0.9741 0.03144
>=30 1.1032 0.84755 1.4359 0.47
Preop GFR <30 0.4439 0.22251 0.8855 0.02117
30-45 1.0491 0.72245 1.5235 0.80
45-60 0.7047 0.49943 0.9943 0.04633
60-90 0.799 0.6123 1.0426 0.10
>=90 Ref
EBL <50 Ref
50-149 0.8808 0.63503 1.2217 0.45
150-299 1.3158 0.9586 1.8061 0.09
>=300 1.3722 0.97973 1.9219 0.07
Intra op transfusion Yes 1.732 1.29912 2.3092 0.00018
No Ref
Time to extubation OR Ref
<12 hrs 1.0379 0.67233 1.6021 0.87
12-24 hrs 1.9328 1.22912 3.0395 0.00433
> 24 hrs 2.6949 1.71027 4.2465 0.00002
Post op MI Yes 4.8497 3.03532 7.7488 <0.0001
No Ref
CHF Yes 6.623 3.98309 11.0127 <0.0001
No Ref
Stroke Yes 6.8061 4.30679 10.7557 <0.0001
No Ref
Spinal cord ischemia, n
(%)
None Ref
Transient 1.7591 0.90149 3.4326 0.10
Present at discharge 2.6417 1.49427 4.6701 0.00083
Post op dialysis Yes 12.0012 7.44553 19.3444 <0.0001
No Ref

21
Table VI. Cox proportional hazards model for 1-year mortality
Variable HR 95% CI P-value
COPD No COPD Ref
Not treated 1.418 1.128 1.781 0.0028
On meds 1.402 1.183 1.66 <.0001
Home Oxygen 1.877 1.458 2.416 <.0001
Age <=60 Ref
61-70 1.444 1.072 1.945 0.0156
71-80 1.786 1.332 2.395 0.0001
>80 2.521 1.843 3.45 <.0001
Respiratory complications Yes 2.804 2.29 3.434 <.0001
No Ref
Pathology Aneurysm Ref
Dissection 0.792 0.616 1.019 0.07
Aneurysm from
dissection
1.008 0.732 1.388 0.96
PAU 1.077 0.767 1.513 0.67
Preop GFR <30 1.614 1.177 2.214 0.003
30-45 1.49 1.174 1.891 0.001
45-60 1.013 0.806 1.274 0.91
60-90 0.905 0.74 1.108 0.33
>=90 Ref
Intra op transfusion Yes 1.49 1.256 1.767 <.0001
No Ref
Time to extubation OR Ref
<12 hrs 1.241 0.959 1.604 0.10
12-24 hrs 1.493 1.119 1.993 0.0065
> 24 hrs 2.735 2.167 3.453 <.0001
Post op MI Yes 2.501 1.946 3.214 <.0001
No Ref
Stroke Yes 2.166 1.659 2.827 <.0001
No Ref
Spinal cord ischemia, n
(%)
None Ref
Transient 1.337 0.895 1.997 0.10
Present at discharge 1.888 1.399 2.55 <.0001
Post op dialysis Yes 2.423 1.877 3.126 <.0001
No Ref
ASA class 1-3 Ref
4-5 1.249 1.08 1.445 0.0028
BMI <18 1.419 1.016 1.981 0.0399
18-24.9 Ref
25-29.9 0.781 0.662 0.921 0.0034
>=30 0.682 0.565 0.823 <.0001
Hgb <10 1.519 1.24 1.861 <.0001
10-11.9 1.26 1.066 1.49 0.0069
>=12 Ref

22
Figure 1. Study flow diagram.

23
Figure 2. Kaplan-Meier survival curves for 1-year survival probability by COPD group.

24
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Creator DiBartolomeo, Alexander Dominic (author)

Core Title Association of chronic obstructive pulmonary disease and mortality following thoracic and complex endovascular aortic repair: a retrospective cohort study

School Keck School of Medicine

Degree Master of Science

Degree Program Clinical and Biomedical Investigations

Degree Conferral Date 2024-05

Publication Date 05/22/2024

Defense Date 05/22/2024

Publisher Los Angeles, California (original), University of Southern California (original), University of Southern California. Libraries (digital)

Tag chronic obstructive pulmonary disease,complex endovascular aortic repair,mortality,OAI-PMH Harvest,thoracic endovascular aortic repair

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Language English

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