ChristinaLee_Research Paper_Final

Running head: ENDOVASCULAR AND OPEN REPAIRS OF POPLITEAL ANEURYSMS
A Comparison of the Effectiveness of Endovascular and Open Repairs of Popliteal Aneurysms
Research Paper
Submitted to Kennesaw Mountain High School
by
CHRISTINA LEE
Kennesaw, Georgia
December 2014

ENDOVASCULAR AND OPEN REPAIRS OF POPLITEAL ANEURYSMS
Abstract
Popliteal artery aneurysms (PAAs) pose a significant threat of limb loss due to the high rates of
thromboembolic complications. The goal of this qualitative exploratory case study was to
compare the post-operative complication rates of open bypass repairs and endovascular stent
graft repairs of PAAs in order to determine if an endovascular repair or open repair results in a
lower post-operative complication rate. To assess the post-operative complications rates for
open bypass repairs and endovascular stent graft repairs, I utilized an online database to examine
each patient’s history and record the age, gender, type of PAA repair, and the presence or lack of
the following: post-operative infection, post-operative endoleaks, post-operative thrombosis,
post-operative stenosis, and necessary reintervention for a poorly functioning stent graft or
bypass. My convenience sample included all endovascular stent graft and open bypass repairs of
PAAs from January 2010 to December 2012 at a vascular surgical office in a large suburban
county in Georgia. Within these confines, surgeons performed 10 open bypass repairs and 13
endovascular stent graft repairs on 16 males from the ages 62 to 85. In this study, the relative
post-operative complication rates differed for each procedure, prompting the need for further
research on the matter. With further research, new evidence could support that one treatment
results in a lower post-operative complication rate, and doctors may be encouraged to select the
safer repair with knowledge of the lower post-operative complication rate. For the purposes of
this study, I defined the safer repair as the repair that resulted in fewer post-operative
complications

Acknowledgements
Thank you to all of the following for your eagerness to help me excel and succeed throughout the
course of this research:
Dr. David Hafner, M.D.
Mrs. Kelly Ingle
Ms. Kristen Younker
Dr. Mimi Dyer, Ed. D.

Table of Contents
Introduction..................................................................................................................................... 1
Statement of the Problem ........................................................................................................... 1
Purpose of the Study................................................................................................................... 2
Research Questions .................................................................................................................... 3
Definition of Key Terms ............................................................................................................ 4
Review of Literature ....................................................................................................................... 5
Causes of PAAs.......................................................................................................................... 5
Risk Factors Associated with PAAs........................................................................................... 6
Diagnosing PAAs ....................................................................................................................... 6
Open Bypass Approach to Repairing PAAs............................................................................... 7
Endovascular Stent Graft Approach to Repairing PAAs ........................................................... 8
Findings of Past Studies Comparing Open and Endovascular Repairs ...................................... 8
Limiting Factors in Past Studies................................................................................................. 9
Summary..................................................................................................................................... 9
Research Method........................................................................................................................... 10
Population and Sample............................................................................................................. 11
Instrumentation......................................................................................................................... 12
Data Collection Procedure........................................................................................................ 12
Analysis Plan............................................................................................................................ 13
Assumptions ............................................................................................................................. 13
Limitations................................................................................................................................ 14
Delimitations ............................................................................................................................ 14
Ethical Assurances.................................................................................................................... 15
Summary................................................................................................................................... 15
Findings......................................................................................................................................... 15
Results ...................................................................................................................................... 16
Evaluation of Findings ............................................................................................................. 18
Summary................................................................................................................................... 18
Implications, Recommendations, and Conclusions ...................................................................... 19
Implications .............................................................................................................................. 20
Recommendations .................................................................................................................... 22
Conclusion................................................................................................................................ 23
References..................................................................................................................................... 24
Appendix A: All Collected Data................................................................................................... 27

ENDOVASCULAR AND OPEN REPAIRS OF POPLITEAL ANEURYSMS 1
Introduction
A popliteal artery aneurysm (PAA) is an excessive localized enlargement of the artery
caused by a weakening of the medial layer of the popliteal vessel wall (DeBakey, 2013). PAAs
are the most common type of peripheral artery aneurysms, accounting for 70% to 80% of all
peripheral artery aneurysms (Antonello et al., 2005). PAAs pose a significant threat of limb loss
due to the high rates of thromboembolic complications (Curl et al., 2007). Limb salvage is
unlikely in symptomatic patients, especially those suffering from acute ischemia (Antonello et
al., 2005).
With the surgical treatment of PAAs, surgeons aim to isolate and exclude the aneurysm
and allow for the restoration of effective blood flow to the lower extremities (Antonello et al.,
2005). In the past, doctors have most commonly repaired PAAs through ligation and a medial or
posterior bypass (Lovegrove, Javid, Magee, & Galland, 2008). In 1994, the option of an
endovascular repair through the interposition of a palmaz stent covered with a
polytetrafluoroethylene (PTFE) graft became available (Cronenwett & Johnston, 2010). Since
the first endovascular repair in 1994, researchers have suggested in various reports that
endovascular repairs are equally as effective as open repairs (Lovegrove et al., 2008).
Statement of the Problem
If PAAs are ineffectively treated, post-operative complications can include, but are not
limited to, loss of patency of the graft or vein, thrombosis– which may lead to acute limb
ischemia– development of arterial ulcers, and infection of the incision site (Cronenwett &
Johnston, 2010). Other indirect factors that may influence the effectiveness of an endovascular
repair or open repair is the length of hospital stay and length of use of anesthesia (Antonello et
al., 2005). It is unclear whether an endovascular repair or an open repair results in a higher rate

of post-operative complications (Cronenwett & Johnston, 2010). The problem associated with
this study is whether an endovascular repair or an open repair of PAAs results in the lowest
percentage of post-operative complications. Due to the wide variety of complications that can
occur if the PAA is not effectively treated, it is imperative that surgeons are aware of the optimal
procedure for repairing PAAs (Mosquera, 2013). If a significant difference exists between the
post-operative complication rates of endovascular stent graft repairs and open bypass repairs, the
public and medical field should be informed, thereby ensuring the effective treatment of PAAs in
the future. If an endovascular repair or open repair does result in fewer post-operative
complications and the medical field and public remains unaware of such a difference, medical
professionals may continue to treat patients in an ineffective and unnecessarily hazardous
manner.
Purpose of the Study
The purpose of this qualitative exploratory case study was to determine if an
endovascular repair is a more effective treatment for PAAs than an open repair. I catalogued and
calculated percentages for the respective number of post-operative infections, post-operative
endoleaks, post-operative thrombosis, post-operative stenosis, and necessity for reintervention
for endovascular stent graft repairs and open bypass repairs. I utilized the resulting trends and
patterns to draw casual conclusions or generalizations about the population. I obtained data from
October to November 2014 using patient records from the Vascular Surgical Associates patient
database at WellStar Kennestone Regional Medical Center. The data included the age, gender,
type of PAA repair, and the presence or lack of the following: post-operative infection, post-
operative endoleaks, post-operative thrombosis, post-operative stenosis, and necessary
reintervention for a poorly functioning stent graft or bypass. I compared the relative post-

operative complication rates of the two procedures by calculating the relative percentages of
each post-operative complication to determine if there was a difference. If the endovascular or
open repair resulted in a lower post-operative complication rate, I will assert that it is the safer
procedure. As information concerning the safety of each procedure becomes more available,
surgeons will be more likely to perform the procedure that results in the least number of post-
operative complications for their patients ("Physicians Oaths," n.d.).
ResearchQuestions
The following are research questions for the study of endovascular and open repairs of
PAAs.
Q1. What is the post-operative complication rate, as determined by post-operative
infections of the surgical site, of open repairs of PAAs?
infections of the surgical site, of endovascular repairs of PAAs?
endoleak rate, of open repairs of PAAs?
endoleak rate, of endovascular repairs of PAAs?
thrombosis, of open repairs of PAAs?
thrombosis, of endovascular repairs of PAAs?
stenosis, of open repairs of PAAs?

stenosis, of endovascular repairs of PAAs?
Q9. What is the post-operative complication rate, as determined by the necessity for
reintervention, of open repairs of PAAs?
Q10. What is the post-operative complication rate, as determined by the necessity for
reintervention, of endovascular repairs of PAAs?
Q11. How do the post-operative complication rates of open repairs and endovascular
repairs compare?
Q11a. Which PAA treatment results in the fewest number of post-operative
complications?
Definition of Key Terms
Arteriosclerosis. A chronic disease characterized by abnormal thickening and hardening
of the arterial walls with resulting loss of elasticity (“Arteriosclerosis,” 2014).
Ischemia. A deficient supply of blood to a body part that is due to obstruction of the
inflow of arterial blood ("Ischemia," 2014).
Aneurysm. The widening of an artery that develops from a weakness or destruction of
the medial layer of the blood vessel (DeBakey, 2013).
Ligation. The surgical process of tying up an anatomical channel such as a blood vessel
("Ligation," 2014).
Medial. Lying or extending toward the median axis of the body (“Medial,” 2014).
Posterior. Situated behind the human body or its parts (“Posterior,” 2014).
Morbidity. A diseased state or symptom (“Morbidity,” 2014).
Patency. The state of being open or exposed ("Patency," 2014).

Stenosis. A narrowing or constriction of the diameter of a bodily passage or orifice
("Stenosis," 2014).
Thrombosis. The formation or presence of a blood clot within a blood vessel
("Thrombosis," 2014).
Distal. Located away from the center of the body ("Distal," 2014).
Autologous. Derived from the same individual (“Autologous,” 2014).
Review of Literature
Arteries generally have thick walls that are excellent for withstanding normal blood
pressures; however, smoking, hypertension, or heart disease may compromise the strength of the
arterial wall and cause an aneurysm to form ("What Is an Aneurysm?," 2011). An aneurysm is a
widening of an artery caused by a weakening of the arterial wall ("What Is an Aneurysm?,"
2011). Rarely, aneurysms form in the popliteal artery (Mohan et al., 2006). The popliteal artery
is located behind the knee and connects the superficial femoral artery in the thigh to the
tibioperoneal trunk in the calf ("Popliteal Artery Aneurysm," n.d.; Knipe & Jones, n.d.). The
normal diameter of a popliteal artery varies from 0.5 to 1.1 centimeters; however, the
development of a PAA can cause the artery to widen to 2.0 to 4.0 centimeters (Cronenwett &
Johnston, 2010). PAAs only affect about 1% of the general population yet PAAs account for
70% to 80% of all peripheral artery aneurysms (Mohan et al., 2006; Cronenwett & Johnston,
2010). PAAs are most common in elderly men (95%) with a median age of 71 (Mosquera,
2013).
Causes of PAAs
The exact cause of PAAs remains unclear (Cronenwett & Johnston, 2010). Hamish et al.
(2006) identified arteriosclerosis as the dominant associated factor. Arteriosclerosis can form

lesions in the arterial wall ("Arteriosclerosis / Atherosclerosis," n.d.). The turbulent blood flow
along such lesions causes the arterial wall to weaken and dilate the artery (Hamish et al., 2006).
The constant motion and associated kinking of the knee may also contribute to the formation of
an aneurysm in the popliteal artery (Hamish et al., 2006).
Risk Factors Associated with PAAs
PAAs can lead to considerable morbidities and are the cause of one in every 5000
hospital admissions (Siauw, Koh, & Walker, 2006). While this particular type of aneurysm does
not pose a high risk of rupturing, it can suddenly thrombose and obstruct blood flow to the lower
leg and foot. The thrombosis may cause severe ischemia which can result in the necessary
amputation of the afflicted limb (Mosquera, 2013). Thirty-six percent of symptomatic patients
ultimately require an amputation, usually as a result of treatment failure (Siauw et al., 2006).
Approximately 60% of PAA patients are symptomatic upon first presentation; 30% present acute
limb ischemia and another 11% present with generalized pain caused by local compression of the
nerves or veins behind the knee (Siauw et al., 2006). Cronenwett and Johnston (2010) believed
that a positive correlation exists between the size of the enlarged aneurysm and the incidence of
symptoms. However, Kirkpatrick et al. (2004) and Ebaugh et al. (2003) argued that aneurysm
size has no bearing on the presence or lack of symptoms.
Diagnosing PAAs
Correctly diagnosing PAAs can be difficult due to their infrequency. Specialists at major
vascular centers only treat approximately five PAAs per year (Hamish et al., 2006). Forty
percent of patients present with asymptomatic PAAs, and healthcare professionals generally
diagnose them by accident (Antonello et al., 2005). It is easier to correctly identify a PAA in a
symptomatic patient; however, the probability of limb salvage in symptomatic patients is greatly

decreased (Cronenwett & Johnston, 2010). Doctors may utilize duplex ultrasonagraphy to image
and diagnose a PAA (Cronenwett & Johnston, 2010). Palpating the popliteal space can also be
effective for diagnosing a PAA though it is an unreliable method (Cronenwett & Johnston,
2010). Once a medical professional confirms a PAA, he utilizes more detailed imaging in order
to indentify the appropriate treatment method for the individual patient (Cronenwett & Johnston,
2010). Common imaging techniques include contrast-enhanced arteriography, magnetic
resonance angiogram (MRA), and computed tomography angiography (CTA) (Cronenwett &
Johnston, 2010).
Open Bypass Approach to Repairing PAAs
and allow for the restoration of effective blood flow to the lower extremities (Cronenwett &
Johnston, 2010). The first open bypass repair was performed in 1785 by John Hunter, and the
procedure has been generally considered an excellent choice for PAA repairs ever since
(Cronenwett & Johnston, 2010). An open bypass repair for PAAs involves the ligation of the
aneurysm and interposition of a bypass graft to maintain healthy blood flow to the lower leg and
foot (Cronenwett & Johnston, 2010). The bypass, which is made of a PTFE prosthetic graft or
autologous vein, connects the superficial femoral artery or common femoral artery to the distal
popliteal artery or peroneal artery (Huang et al., 2007). Surgeons select the inflow and outflow
sites on a case-by-case basis depending upon the patient anatomy and size of the PAA (Hamish
et al., 2006). Hamish et al. (2006) and Huang et al. (2007) agreed that utilization of the
autologous vein poses lower risks of post-operative complications in comparison to the
utilization of a prosthetic graft. If the patient is classified low-risk in terms of operative health,
surgeons will opt to harvest the great saphenous vein (GSV) for use as the autologous vein for

the bypass graft (Cronenwett & Johnston, 2010).
Endovascular Stent Graft Approach to Repairing PAAs
In 1994, the option of an endovascular repair through the interposition of a palmaz stent
covered with a PTFE graft became available (Cronenwett & Johnston, 2010). Since the first
endovascular repair in 1994, researchers have suggested in various reports that endovascular
repairs are equally as effective as open repairs, or possibly even more effective (Lovegrove et al.,
2008). The most commonly used stent graft is the Hemobahn graft (W. L. Gore & Associates,
Flagstaff, Arizona; Antonello et al., 2005). The Hemobahn graft is built with a unique self-
expanding nitinol stent (Antonello et al., 2005). The nitinol stent within the Hemobahn graft has
a wide range of flexibility and radial stiffness, making it a good candidate for a bypass placed
behind the constantly flexing knee joint (Antonello et al., 2005).
In an endovascular approach, surgeons make a small incision in the groin, and feed a
catheter through the superficial femoral artery to the popliteal artery ("Endovascular Stent Graft,"
n.d.). Surgeons feed the stent graft into the catheter and position it by using contrast dye and x-
ray imaging ("Endovascular Stent Graft," n.d.). Once correctly positioned, the surgeon deploys
the stent graft and expands the graft with a balloon to ensure a tight seal to the arterial walls
above and below the PAA ("Endovascular Stent Graft," n.d.). If the stent graft is not long
enough, the surgeon may have to insert and overlap multiple grafts (Tielliu et al., 2010).
However, surgeons should avoid overlapping the graft as doing so increases the chances of
kinking or thrombosing in the graft (Tielliu et al., 2010).
Findings of Past Studies Comparing Open and Endovascular Repairs
Within the medical community, there is debate over the relative superiority of
endovascular stent graft repairs and open bypass repairs (Cronenwett & Johnston, 2010). Each

procedure has different types of post-operative complications and recovery times (Cronenwett &
Johnston, 2010). Taurino et al. (2013) concluded that as long as the surgeon correctly ligates the
aneurysm, a patient who receives an open bypass repair will experience a low rate of post-
operative complications. Conversely, Rosenthal, Matsuura, Clark, Kirby, and Knoepp (2000)
believed the endovascular approach is the appropriate repair in all cases because the
endovascular repair does not require the long incisions required for the open bypass repair,
avoids most wound complications due to the small size of the incision made in the groin, and
usually results in a substantially shorter stay in the hospital. Mohan et al. (2006) and Antonello
et al. (2005) compromised after their studies and agreed that both procedures were good for
various reasons. However, the authors believed that as technology in grafts advances, the
endovascular approach will become the superior repair (Mohan et al. 2006; Antonello et al.
2005). Lovegrove et al. (2008) concluded that neither procedure is superior, and that each
patient needs to be examined on an individual basis in order to determine which procedure is
appropriate per the patient’s anatomy, current health, and lifestyle and will result in the fewest
post-operative complications.
Limiting Factors in Past Studies
Unfortunately for researchers, PAAs are rare and therefore finding data on enough PAA
patients to calculate statistically significant results can be difficult (Siauw et al., 2006). Many of
the studies on this topic contain data that cover a 10 to 20 year time span. A time span of this
length adds numerous confounding variables into the data due to advances in medicine and the
learning curve placed on new procedures (Curl et al., 2007).
Summary
PAAs are the most common type of peripheral artery aneurysm. Surgeons commonly

perform endovascular stent graft repairs and open bypass repairs for PAA repair (Cronenwett &
Johnston, 2010). While a PAA does not pose a high risk of rupturing, it can suddenly thrombose
and obstruct blood flow to the lower leg and foot. The thrombosis may cause severe ischemia
which can result in the necessary amputation of the afflicted limb (Mosquera, 2013). Correctly
diagnosing PAAs can be difficult due to their infrequency (Hamish et al., 2006), however
medical professionals may use duplex ultrasonagraphy to quickly image and diagnose a PAA
(Cronenwett & Johnston, 2010). Once a medical professional confirms a PAA, he may utilize
more detailed imaging in order to indentify the appropriate treatment method for the individual
patient (Cronenwett & Johnston, 2010). With the surgical treatment of PAAs, surgeons aim to
isolate and exclude the aneurysm and allow for the restoration of effective blood flow to the
lower extremities (Cronenwett & Johnston, 2010). An open bypass repair for PAAs involves the
ligation of the aneurysm and interposition of a bypass graft to maintain healthy blood flow to the
lower leg and foot (Cronenwett & Johnston, 2010). In an endovascular approach, a surgeon
makes a small incision in the groin, and feeds a catheter through the superficial femoral artery to
the popliteal artery ("Endovascular Stent Graft," n.d.). The surgeon positions the stent graft
inside the PAA, and the graft acts as an internal bypass for blood flow ("Endovascular Stent
Graft," n.d.). Unfortunately for researchers, PAAs are rare and therefore finding data on enough
PAA patients to calculate statistically significant results can be difficult (Siauw et al., 2006).
Research Method
A qualitative exploratory case study was the proposed research method for this study. An
exploratory case study is appropriate when the researcher cannot provide a clear or single set of
outcomes for the treatment (Yin, 2003). It is unclear whether an endovascular repair or an open
repair results in a higher rate of post-operative complications (Cronenwett & Johnston, 2010).

Therefore, an exploratory case study was suitable for this study. A qualitative case study is most
suitable for studies in which the compiled data are limited but detailed (Leedy & Ormrod, 2005).
Therefore, a qualitative case study was suitable for this study. In this study, I evaluated the
endovascular stent graft repair and open bypass repair on multiple parameters– the relative rates
of post-operative infection, post-operative endoleaks, post-operative thrombosis, post-operative
stenosis, and necessity for reintervention. I collected all cases of PAA repairs from January 2010
to December 2012 at a vascular surgical office in a large suburban county in Georgia through
convenience sampling. When sampling by convenience, the researcher only collects data that
are easily available rather than randomly collecting data that are representative of the population
as a whole (Leedy & Ormrod, 2005). The limited time given to complete this study, the
limitations of medical privacy, and the low rates of occurrences of PAAs made a convenience
sampling method the only practical data collection method. Due to the limited available sample,
each case consisted of one PAA repair and corresponding results. Consequently, one patient
may have consisted of multiple cases if the patient had more than one PAA repair or required
reintervention of a stent graft or bypass.
Population and Sample
When researchers utilize convenience sampling to collect data, they cannot apply the
observed trends to a larger population (Leedy & Ormrod, 2005). Since the method of data
collection was convenience sampling, I could not apply the results of this study to the total
population of PAA repairs. The population in this study was limited to all PAA repairs
performed by a vascular surgical office in a large suburban county in Georgia. The convenience
sample included all endovascular stent graft and open bypass repairs of PAAs from January 2010
to December 2012 at a vascular surgical office in a large suburban county in Georgia. Within

these confines, surgeons performed 10 open bypass repairs and 13 endovascular stent graft
repairs on 16 males from the ages 62 to 85 years.
Instrumentation
I utilized the online database of Vascular Surgical Associates’ patients, Allscripts
Professional EHR with Citrix Clinical Modules. A Vascular Surgical Associates secretary culled
patient records and identified 16 patients who had undergone endovascular stent graft repairs or
open bypass repairs for PAAs and compiled a list of those patients. I employed the online
database to access the identified patient records and evaluate their treatments of PAAs.
Data Collection Procedure
In this qualitative exploratory case study, I collected the convenience sample by
gathering information on PAA repairs from the online database, Allscripts Professional EHR. A
secretary at Vascular Surgical Associates utilized search criteria to locate qualified patient’s
records. The secretary searched for all patients diagnosed with PAAs (database code 442.3) who
had undergone open bypass repairs or endovascular stent graft repairs (database codes 37226,
35152, and 35151) within the service dates January 1, 2010 through December 31, 2012.
Sixteen patients matched these criteria and the secretary provided their patient numbers to me. I
logged onto a doctor’s computer in the Vascular Surgical Associates office in Marietta, Georgia
and logged into Allscripts Professional EHR clinical module using the doctor’s credentials. I
utilized the patient numbers to pull digital patient charts and gather data concerning their PAA,
treatment of the PAA, and post-operative complications. I examined each patient’s history and
recorded the age, gender, type of PAA repair, and the presence or lack of the following: post-
operative infection, post-operative endoleaks, post-operative thrombosis, post-operative stenosis,
and necessary reintervention for a poorly functioning stent graft or bypass. I collected data

intermittently over the course of 4 weeks.
Analysis Plan
I grouped data for each procedure and examined each endovascular stent graft repair or
open bypass repair as an individual case in this qualitative exploratory case study. Examining
the data in this way resulted in 23 total cases: 10 open bypass repairs and 13 endovascular stent
graft repairs performed on 16 males from the ages 62 to 85. I catalogued and calculated
percentages for the respective number of post-operative infections, post-operative endoleaks,
post-operative thrombosis, post-operative stenosis, and necessity for reintervention for each
procedure. Researchers cannot compute statistical analysis with small samples (Leedy &
Ormrod, 2005). Due to the rarity of PAAs and the resulting small number of cases available for
analysis through Vascular Surgical Associates, I could not compute statistical analysis with this
data set. According to the protocol for qualitative analysis, researchers may only observe trends
and patterns with small data sets (Leedy & Ormrod, 2005). I utilized the trends and patterns
observed in this study to draw casual conclusions or generalizations about the population.
Assumptions
A necessary assumption was that the doctors, physician’s assistants, and surgeons at
Vascular Surgical Associates correctly diagnosed patients with PAAs. This assumption is
acceptable because all employees at Vascular Surgical Associates who may have diagnosed the
patients are trained professionals. It was also necessary to assume that patient records were
accurate concerning basic patient information, history, PAA treatment, and post-operative care of
the PAAs. I warranted this assumption because health care professionals make it a priority to
truthfully and accurately record patient information, and insurance companies require accurate
information for their coverage. For the purposes of this study, I assumed that all surgeons

performed the endovascular stent graft repairs and open bypass repairs to the same standards and
with the same amount of care. I made this assumption because of the standardized procedural
protocol that exists for both repairs. I also assumed that all post-operative complications relate
directly to the repair of a PAA with an endovascular stent graft or an open bypass, instead of an
outstanding medical condition or failure to follow post-operative orders from the surgeons.
While this assumption may have decreased the validity of the study, it was necessary in order to
make generalizations or draw casual conclusions. There was no way to quantify a patient’s
noncompliance, and most patients do not report their noncompliance to doctors, thus the doctors
did not record the information the patients’ charts.
Limitations
Patient confidentiality, sampling method, and sample size limited this study. The
restraints of patient confidentiality prevented the collection of data from patient records not
directly affiliated with Vascular Surgical Associates. This necessitated convenience sampling
and led to a small sample size for endovascular repairs and open repairs. Convenience sampling
made it impossible to generalize the results of this study beyond patients treated at the
experiment location. Researchers cannot compute statistical analysis on small samples and,
without statistical data, they can only draw casual conclusions (Leedy & Ormrod, 2005).
Therefore, I drew only casual conclusions from the data in this study.
Delimitations
For the purpose of this study, I did not consider patient history and current medical
conditions. Although a history of smoking, drug abuse, alcoholism, hypertension, blood clotting
disorders, or heart disease can affect the effectiveness of an open bypass repair or endovascular
stent graft repair, time restraints prevented the collection and analysis of this data.

Ethical Assurances
I closely followed ethical guidelines associated with medical research. I maintained
patient identity and confidentiality. I completed all necessary Wellstar and Vascular Surgical
Associates paperwork prior to commencing data collection and followed all Wellstar and
Vascular Surgical Associates research protocols during data collection. I carefully and precisely
collected all data to ensure the correct data retained its original association to particular patients
and procedures. I did not falsify any data. I reported and referenced all information truthfully.
Summary
A qualitative exploratory case study was the proposed research method for this study.
The population in this study was limited to all PAA repairs performed by a vascular surgical
office in a large suburban county in Georgia. The convenience sample included all endovascular
stent graft repairs and open bypass repairs of PAAs from January 2010 to December 2012 at a
vascular surgical office in a large suburban county in Georgia. Within these confines, surgeons
performed 10 open bypass repairs and 13 endovascular stent graft repairs on 16 males from the
ages 62 to 85. I utilized an online database to examine each patient’s history and record the age,
gender, type of PAA repair, and the presence or lack of the following: post-operative infection,
post-operative endoleaks, post-operative thrombosis, post-operative stenosis, and necessary
reintervention for a poorly functioning stent graft or bypass. I catalogued and calculated
percentages for the respective number of post-operative infections, post-operative endoleaks,
post-operative thrombosis, post-operative stenosis, and reinterventions for each. I qualitatively
analyzed the results and made generalizations about endovascular stent graft repairs and open
bypass repairs.
Findings

The goal of this research was to compare the post-operative complication rates of open
bypass repairs and endovascular stent graft repairs of PAAs in order to determine if an
endovascular repair or open repair results in a lower post-operative complication rate, thus
indicating that one procedure is safer. In this study, the relative post-operative complication
rates differed for each procedure, prompting the need for further research on the matter. With
further research, evidence could be found to support that one treatment is safer than the other,
and doctors may be encouraged to select the safer repair with knowledge of the lower post-
operative complication rate. For the purposes of this study, I defined the safer repair as the
repair that resulted in fewer post-operative complications. To assess the post-operative
complications rates for open bypass repairs and endovascular stent graft repairs, I utilized an
online database to examine each patient’s history and record the age, gender, type of PAA repair,
and the presence or lack of the following: post-operative infection, post-operative endoleaks,
post-operative thrombosis, post-operative stenosis, and necessary reintervention for a poorly
functioning stent graft or bypass. I catalogued and calculated percentages for the respective
number of post-operative infections, endoleaks, thrombosis, stenosis, and necessity for
reintervention for each procedure. I employed these percentages to determine if one procedure
resulted in a lower post-operative complication rate.
Results
A total of 23 cases were included in the sample. I detailed all collected data in Table 1
and Table 2. Of which, 10 were open bypass repairs, and 13 were endovascular stent graft
repairs. The age range of patients was 62-85 years, and the average age was 73.81 years. The
sample consisted of only males. Ten percent of open bypass repairs resulted in infection (one
out of ten cases). Conversely, 7.69% of endovascular stent graft repairs resulted in infection

(one out of 13 cases). Zero percent of open bypass repairs resulted in endoleaks (zero out of ten
cases). 15.38% of endovascular stent graft repairs resulted in endoleaks (two out of 13 cases).
Thirty percent of open bypass repairs resulted in thrombosis (three out of ten cases). 38.46% of
endovascular stent graft repairs resulted in thrombosis (five out of 13 cases). Thirty percent of
open bypass repairs resulted in stenosis (three out of ten cases). 15.38% of endovascular stent
graft repairs resulted in stenosis (two out of 13 cases). Thirty percent of open bypass repairs
required reintervention (three out of ten cases). 23.07% of endovascular stent graft repairs
required reintervention (two out of 13 cases). I summarized a comparison of the percentages in
Figure 1.
Figure 1. Comparison of post-operative complication rates of open bypass repairs and endovascular stent
graft repairs for PAAs.
Figure 1 depicts that open bypass repairs resulted in higher post-operative complication
rates than endovascular stent graft repairs in three of the five categories: infection, stenosis, and
necessity of reintervention. Endovascular stent graft repairs resulted in higher post-operative
complication rates than open bypass repairs in the two of the five categories: endoleaks and
0
5
10
15
20
25
30
35
40
45
Percentage of
cases with
infection
Percentage of
cases with
endoleak
Percentage of
cases with
thrombosis
Percentage of
cases with
stenosis
Percentage of
cases requiring
reintervention
Open bypass
repair
Endovascular
stent graft repair

thrombosis.
Evaluation of Findings
Researchers cannot compute statistical analysis with small samples (Leedy & Ormrod,
2005). Therefore, I could not compute statistical analysis with the data in this study. According
to the protocol for qualitative analysis, researchers may only observe general trends and patterns
in the data (Leedy & Ormrod, 2005). Open bypass repairs resulted in higher post-operative
complication rates than endovascular stent graft repairs in three of the five categories, while
endovascular stent graft repairs resulted in higher post-operative complication rates than open
bypass repairs in two of the five categories. Convenience sampling and a small sample size can
lead to error (Leedy & Ormrod, 2005), and consequently there was an expected amount of error
within the data. It is possible that sampling error attributed to the differences in the post-
operative complication rates. Lovegrove et al. (2008) concluded that neither procedure results in
a higher post-operative complication rate, and that a surgeon should examine each patient
individually in order to determine which procedure is appropriate per the patient’s anatomy,
current health, and lifestyle. Mohan et al. (2006) and Antonello et al. (2005) agreed that neither
procedure was safer; however, as technology in grafts advances, the endovascular approach will
become the superior repair.
Summary
indicating that one procedure is safer. Researchers cannot compute statistical analysis with small
samples (Leedy & Ormrod, 2005). Therefore, I could not compute statistical analysis with the

data in this study. According to the protocol for qualitative analysis, researchers may only
observe general trends and patterns in the data (Leedy & Ormrod, 2005). A total of 23 cases
were included in the sample. Of which, 10 were open bypass repairs, and 13 were endovascular
stent graft repairs. Open bypass repairs resulted in higher post-operative complication rates than
endovascular stent graft repairs in three of the five categories: infection, stenosis, and necessity
of reintervention. Endovascular stent graft repairs resulted in higher post-operative complication
rates than open bypass repairs in the two of the five categories: endoleaks and thrombosis.
Implications, Recommendations, and Conclusions
and allow for the restoration of effective blood flow to the lower extremities (Antonello et al.,
2005). Within the medical community there is debate regarding the relative superiority of
endovascular stent graft repairs and open bypass repairs (Cronenwett & Johnston, 2010). The
goal of this research was to compare the post-operative complication rates of open bypass repairs
and endovascular stent graft repairs of PAAs in order to determine if an endovascular repair or
open repair results in a lower post-operative complication rate, thus indicating that one procedure
is safer. A qualitative exploratory case study was the research method for this study. I utilized
an online database to examine each patient’s history and record the age, gender, type of PAA
repair, and the presence or lack of the following: post-operative infection, post-operative
endoleaks, post-operative thrombosis, post-operative stenosis, and necessary reintervention for a
poorly functioning stent graft or bypass. A total of 23 cases were included in the sample. I
detailed all collected data in Table 1 and Table 2. Of which, 10 were open bypass repairs, and 13
were endovascular stent graft repairs. The overall age range of patients was 62-85 years, and the
average age was 73.81 years. Researchers cannot compute statistical analysis with small

samples (Leedy & Ormrod, 2005). Therefore, I could not compute statistical analysis with the
data in this study. According to the protocol for qualitative analysis, researchers may only
observe general trends and patterns in the data (Leedy & Ormrod, 2005).
Implications
In this study, I utilized an online database to examine each patient’s history and record
the age, gender, type of PAA repair, and the presence or lack of the following: post-operative
infection, post-operative endoleaks, post-operative thrombosis, post-operative stenosis, and
necessary reintervention for a poorly functioning stent graft or bypass. I catalogued and
calculated percentages for the respective number of post-operative infections, post-operative
endoleaks, post-operative thrombosis, post-operative stenosis, and reinterventions. I observed
general trends in the data and made generalizations about endovascular stent graft repairs and
open bypass repairs.
Concerning post-operative infection, 10% of open bypass repairs resulted in infection,
and 7.69% of endovascular stent graft repairs resulted in infection. A difference of 2.31% does
not imply a substantial difference between the two procedures. Researchers attributed these
similar rates of post-operative infection to the easy access to effective and inexpensive
antibiotics (Taurino et al., 2013). The similar rates contradict the conclusion made by Rosenthal
et al. (2000). Rosenthal et al. (2000) believed that the endovascular approach avoids most
wound complications because it does not require the long incisions required for the open bypass
repair. Regarding post-operative endoleaks, 0% of open bypass repairs resulted in endoleaks,
and 15.38% of endovascular stent graft repairs experienced endoleaks. Due to the ballooning
process involved in the insertion of an endovascular stent graft, a higher rate of post-operative
endoleaks is expected ("Endovascular Stent Graft," n.d.).

Of the total cases, 30% of open bypass repairs resulted in post-operative thrombosis of
the bypass, and 38.46% of endovascular stent graft repairs resulted in post-operative thrombosis
of the stent graft. Post-operative thrombosis of the stent graft is a common concern of vascular
surgeons and a high rate of post-operative thrombosis for endovascular repairs should be
expected ("Endovascular Stent Graft," n.d.). Conversely, post-operative thrombosis is not a
common occurrence in open bypasses (Cronenwett & Johnston, 2010). Nevertheless, 30% of
open bypass repairs resulted in post-operative thrombosis of the bypass. Such a starch
contradiction between the results of this study and the existing literature written by Cronenwett
and Johnson (2010) reveals the need for further research on the subject.
Concerning post-operative stenosis of the graft, 30% of open bypass repairs resulted in
post-operative stenosis of the bypass, and 15.38% of endovascular stent graft repairs resulted in
post-operative stenosis of the stent graft. I attribute the higher rate of post-operative stenosis in
open bypass repairs to the use of a prosthetic bypass instead of an autologous bypass. Hamish et
al. (2006) and Huang et al. (2007) agreed that utilization of the autologous vein poses lower risks
of post-operative complications in comparison to the utilization of a prosthetic graft.
Of the total cases reintervention, 30% of open bypass repairs required reintervention, and
23.07% of endovascular stent graft repairs required reintervention. The difference between these
two rates is the most significant of the study. While the other post-operative complications may
cause the patient undue difficulties and require extra treatment, therapy, or medication, the
necessity for reintervention requires an entire additional procedure that involves more anesthesia,
medication, recovery, and an additional stay in the hospital. For patients who are elderly and in
poor health, reintervention causes undue stress to their bodies (Cronenwett & Johnston, 2010).
The relative rates of a necessity for reintervention differed by 6.93%. A difference of nearly 7%

calls into question the claims made by Lovegrove et al. (2008) and Cronenwett & Johnston
(2010) who stated that there is no difference in post-operative complication rates or the necessity
for reintervention between open bypass repairs and endovascular stent graft repairs. The
contradictions between the results of this study and the existing literature written by Cronenwett
and Johnson and Lovegrove et al. reveal the need for further research on the subject.
Recommendations
Some of the general trends observed in this study contradict the observations made by
Rosenthal et al. (2000), Cronenwett and Johnston (2010), and Lovegrove et al. (2008). The most
extreme contradictions occurred in the post-operative thrombosis rates of open bypass repairs
and the relative difference between the rates of necessity for reintervention between open bypass
repairs and endovascular stent graft repairs. An experimental study that includes a large, random
sample alleviates the stress of confounding variables (Leedy & Ormrod, 2005), and hence should
be utilized to draw firm conclusions in the presence of the confounding variables inherent to a
medical study. Such a study could contain much needed statistically significant data that
researchers could formulate into concrete conclusions. Additionally, future researchers should
conduct studies that are not limited by patient confidentiality and lack of access to certain patient
records. With unlimited access to patient records, the researcher could discern the pre-operative
condition of the aneurysm. Researchers should asses the pre-operative size of the aneurysm and
the pre-operative thrombosis or stenosis since these could have confounding effects on the post-
operative complication rates. With unlimited access to patient records, it may be possible to
determine the compliance of each patient concerning his/ her own post-operative care. After the
treatment of PAAs, medical professionals prescribe most patients an anti-coagulant medication
and a certain amount of exercise to accomplish each day (Cronenwett & Johnston, 2010). While

some patients are compliant and follow the surgeon’s orders closely, others are non-compliant.
The patient’s compliancy with the surgeons orders have a direct result on the post-operative
complications the patient will experience. The ability to assess the compliance of each patient
will alleviate the effect of confounding variables on the final rates of post-operative complication
rates.
Conclusion
indicating that one procedure is safer. A qualitative exploratory case study was the research
method for this study. I utilized an online database to examine each patient’s history and record
the age, gender, type of PAA repair, and the presence or lack of the following: post-operative
infection, post-operative endoleaks, post-operative thrombosis, post-operative stenosis, and
necessary reintervention for a poorly functioning stent graft or bypass. Some of the general
trends observed in this study contradict the observations made by Rosenthal et al. (2000),
Cronenwett and Johnston (2010), and Lovegrove et al. (2008). The most extreme contradictions
occurred in the post-operative thrombosis rates of open bypass repairs and the relative difference
between the rates of necessity for reintervention between open bypass repairs and endovascular
stent graft repairs. An experimental study that includes a large, random sample alleviates the
stress of confounding variables (Leedy & Ormrod, 2005), and hence should be utilized to draw
firm conclusions in the presence of the confounding variables inherent to a medical study.
Additionally, future researchers should conduct studies that are not limited by patient
confidentiality and lack of access to certain patient records.

References
Antonello, M., Frigatti, P., Battocchio, P., Lepidi, S., Cognolato, D., Dall'Antonia, A., ... Grego,
F. (2005). Open repair versus endovascular treatment for asymptomatic popliteal artery
aneurysm: Results of a prospective randomized study. Journal of Vascular Surgery,
42(2), 185-193. doi: 10.1016/j.jvs.2005.04.049
Arteriosclerosis. (2014). In Merriam-Webster. Retrieved from http://www.merriam-
webster.com/dictionary/arteriosclerosis
Autologous [Def. 1]. (2014). In Merriam-Webster. Retrieved December 1, 2014, from
http://www.merriam-webster.com/dictionary/autologous
Cronenwett, J. L., & Johnston, K. W. (2010). Lower extremity aneurysms. In Rutherford's
vascular surgery (7th ed., pp. 2110-2127). Philadelphia, PA: Saunders Elsevier.
Curl, M. A., Geraghty, P. J., Merino, O. A., Veeraswamy, R. K., Rubin, B. G., Sanchez, L. A.,
... Sicard, G. A. (2007). Mid-term outcomes of endovascular popliteal artery aneurysm
repair. Journal of Vascular Surgery, 45(3), 505-510. doi: 10.1016/j.jvs.2006.09.064
DeBakey, M. E. (2013, November 10). Aneurysm. In Encyclopedia Britannica. Retrieved from
http://www.britannica.com/EBchecked/topic/24387/aneurysm
Distal [Def. 1a]. (2014). In Merriam-Webster Medical Dictionary. Retrieved from
http://www.merriam-webster.com/dictionary/distal
Ebaugh, J. L., Morasch, M. D., Matsumura, J. S., Eskandari, M. K., Meadows, W. S., & Pearce,
W. H. (2003). Fate of excluded popliteal artery aneurysms. Journal of Vascular Surgery,
37(5), 954-959. doi: 10.1067/mva.2003.258
Endovascular stent graft. (n.d.). Retrieved from
http://www.vascularweb.org/vascularhealth/Pages/endovascular-stent-graft.aspx
Hamish, M., Lockwood, A., Cosgrove, C., Walker, A. J., Wilkins, D., & Ashley, S. (2006).
Management of popliteal artery aneurysms. ANZ Journal of Surgery, 76(10), 912-915.
doi: 10.1111/j.1445-2197.2006.03903.x
Huang, Y., Gloviczki, P., Noel, A. A., Sullivan, T. M., Kalra, M., Gullerud, R. E., ... Bower, T.
C. (2007). Early complications and long-term outcome after open surgical treatment of
popliteal artery aneurysms: Is exclusion with saphenous vein bypass still the gold
standard? Journal of Vascular Surgery, 45(4), 706-715. doi: 10.1016/j.jvs.2006.12.011
Ischemia. (2014). In Merriam-Webster. Retrieved from http://www.merriam-
webster.com/medical/ischemia
Kirkpatrick, U. J., Mcwilliams, R. G., Martin, J., Brennan, J. A., Gilling-Smith, G. L., & Harris,

P. L. (2004). Late complications after ligation and bypass for popliteal aneurysm. British
Journal of Surgery, 91(2), 174-177. doi: 10.1002/bjs.4426
Knipe, H., & Jones, J. (n.d.). Popliteal artery. Retrieved from
http://radiopaedia.org/articles/popliteal-artery
Leedy, P. D., & Ormrod, J. E. (2005). Practical research planning and design (8th ed.). Upper
Saddle River, NJ: Pearson.
Ligation [Def. 1a]. (2014). In Merriam-Webster. Retrieved from http://www.merriam-
webster.com/medical/ligation?show=0&t=1410394972
Lovegrove, R. E., Javid, M., Magee, T. R., & Galland, R. B. (2008). Endovascular and open
approaches to non-thrombosed popliteal aneurysm repair: A meta-analysis. European
Journal of Vascular and Endovascular Surgery, 36(1), 96-100. doi:
10.1016/j.ejvs.2008.02.002
Medial [Def. 2b]. (2014). In Merriam-Webster. Retrieved December 1, 2014, from
http://www.merriam-webster.com/dictionary/medial
Mohan, I., Bray, P., Harris, J., May, J., Stephen, M., Bray, A., & White, G. (2006). Endovascular
popliteal aneurysm repair: Are the results comparable to open surgery? European Journal
of Vascular and Endovascular Surgery, 32(2), 149-154. doi: 10.1016/j.ejvs.2006.01.009
Morbidity. (2014). In Merriam-Webster. Retrieved from http://www.merriam-
webster.com/medical/morbidity
Patency. (2014). In Merriam-Webster. Retrieved from http://www.merriam-
webster.com/medical/patency
Physicians oaths. (n.d.). Retrieved from http://www.aapsonline.org/ethics/oaths.htm
Posterior [Def. 2b]. (2014). In Merriam-Webster. Retrieved December 1, 2014, from
http://www.merriam-webster.com/dictionary/posterior
Rosenthal, D., Matsuura, J. H., Clark, M. D., Kirby, L. B., & Knoepp, L. F. (2000). Popliteal
artery aneurysms: Is endovascular reconstruction durable? Journal of Endovascular
Therapy, 7(5), 394-398. doi: 10.1583/1545-1550(2000)0072.0.CO;2
Siauw, R., Koh, E. H., & Walker, S. R. (2006). Endovascular repair of popliteal artery
aneurysms: Techniques, current evidence and recent experience. ANZ Journal of Surgery,
76(6), 505-511. doi: 10.1111/j.1445-2197.2006.03745.x
Stenosis. (2014). In Merriam-Webster. Retrieved from http://www.merriam-
webster.com/medical/stenosis

Taurino, M., Filippi, F., Ficarelli, R., Fantozzi, C., Dito, R., Brancadoro, D., & Rizzo, L. (2013).
Different approaches in popliteal artery aneurysm management. European Surgery,
45(4), 221-226. doi: 10.1007/s10353-013-0221-0
Thrombosis. (2014). In Merriam-Webster. Retrieved from http://www.merriam-
webster.com/medical/thrombosis
Tielliu, I. F., Zeebregts, C. J., Vourliotakis, G., Bekkema, F., Van den Dungen, J. A., Prins, T.
R., & Verhoeven, E. L. (2010). Stent fractures in the Hemobahn/viabahn stent graft after
endovascular popliteal aneurysm repair. Journal of Vascular Surgery, 51(6), 1413-1418.
doi: 10.1016/j.jvs.2009.12.071
What Is an Aneurysm? (2011, April 1). Retrieved from http://www.nhlbi.nih.gov/health/health-
topics/topics/arm/
Yin, R. K. (2003). Case study research: Design and methods (3rd ed.). Thousand Oaks, CA:
Sage.

Appendix A: All Collected Data
Table 1
Post-Operative Complication Information from Vascular Surgical Associates
Open Bypass Repairs Dating from January 2010 through December 2012
Case number Infection Endoleaks Stenosis Thrombosis Reintervention
1 - - - - -
2 - - - + +
3 - - - - -
4 - - - - -
5 - - + - -
6 - - - - -
7 - - + - +
8 - - - - -
9 - - - + +
10 + - - + -
Note. A dash mark (-) denotes the repair did not result in the post-operative complication. A plus
sign (+) denotes the repair resulted in the post-operative complication.
Table 2
Post-Operative Complication Information from Vascular Surgical Associates
Endovascular Stent Graft Repairs Dating from January 2010 through December 2012
Case number Infection Endoleaks Stenosis Thrombosis Reintervention
11 - - + - -
12 - - - + -
13 - - - - -
14 + + - - -
15 - - - - -
16 - - - - -
17 - - - + +
18 - - - + +
19 - - - + -
20 - - - - -
21 - - - - -
22 - + - + -
23 - - + - -
Note. A dash mark (-) denotes the repair did not result in the post-operative complication. A plus
sign (+) denotes the repair resulted in the post-operative complication.

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