From the Society for Vascular Surgery
Endovascular aneurysm repair with suprarenal vs
infrarenal fixation: A study of renal effects
Shane S. Parmer and Jeffrey P. Carpenter , for the Endologix Investigators,* Philadelphia, Penn
Objectives: Although suprarenal fixation may be of benefit during endovascular aneurysm repair (EVAR), its safety with
regards to renal effects remains uncertain. To date, there has been no controlled study of the topic, with most reports
relying upon single-center experiences that use heterogeneous patient populations and devices from different manufacturers. The purpose of this analysis was to evaluate the effect of suprarenal fixation on renal function by comparing
homogeneous patient populations receiving EVAR grafts from a single manufacturer that are identical in design and
delivery method, except for utilizing either suprarenal (SR) or infrarenal (IR) fixation.
Methods: During two pivotal US Food and Drug Administration trials, 283 patients underwent EVAR with the Powerlink
bifurcated graft. The trials’ inclusion and exclusion criteria and grafts were identical except for fixation scheme. Clinical,
laboratory, and computed tomographic (CT) data were retrospectively reviewed. A comparison of preoperative,
perioperative (1 to 7 days), and postoperative (>7 days) alterations in serum creatinine (SCr), creatinine clearance (CrCl),
and blood pressure was performed. Renal adverse events were determined by CT scan and clinical chart review and
included renal infarction, renal artery stenosis (either progressive or requiring renal stent placement), and renal artery
occlusion.
Results: Both SR and IR groups demonstrated a significant increase in SCr and a decrease in CrCl over time. No significant
difference in SCr or CrCl existed between groups during any time period. There were no differences in postoperative renal
impairment (IR, 10.2%; SR, 7.6%, P ⴝ .634), the need for hemodialysis (IR, 0.7%; SR, 0%, P ⴝ 1.00), or systolic and
diastolic blood pressure during subsequent follow-up between treatment groups. There was no significant difference in
the number of renal adverse events detected by CT between the IR (10, 6.8%) and SR (3, 3.8%) groups (P ⴝ .550).
Conclusion: Suprarenal fixation does not lead to a significant increase in acute renal events, renal impairment, or alteration
in blood pressure compared with infrarenal fixation. Patients undergoing aneurysm repair with devices that use either
suprarenal or infrarenal fixation develop progressive renal dysfunction over time. Further studies are needed to determine
the long-term effects of suprarenal fixation on renal function and progression of renal artery stenosis. ( J Vasc Surg 2006;
43:19-25.)
Since the first description of endovascular abdominal
aortic aneurysm repair (EVAR) in 1991 by Parodi, Palmaz,
and Barone,1 the use of this technique has become widespread. With increased acceptance by clinicians and patients, EVAR is rapidly overtaking open repair as the predominant form of repair for abdominal aortic aneurysms.
However, despite the enthusiasm for this approach, one
third of all patients remain ineligible for these grafts. Furthermore, over half of patients at highest risk for surgery
and who would benefit most fail to qualify. The limitations
of endovascular repair are largely due to anatomic constraints, including proximal fixation inadequacies and small
delivery vessels.2 Although advances that come with new
device development seek to solve these issues, proximal
neck angulation and length continue to be limiting factors.
From the Division of Vascular Surgery, Hospital of the University of
Pennsylvania.
Competition of interest: Drs Parmer and Carpenter have received consulting
fees from Endologix, Inc.
*The principal investigators and their respective centers are listed in Appendix A for the infrarenal devices and Appendix B for the suprarenal devices.
Additional material for this article may be found online at www.mosby.com/
jvs.
Reprint requests: Jeffrey P. Carpenter, MD, Professor, Division of Vascular
Surgery, Hospital of the University of Pennsylvania, 3400 Spruce Street,
Philadelphia, PA 19104 (e-mail: [email protected]).
0741-5214/$32.00
Copyright © 2006 by The Society for Vascular Surgery.
doi:10.1016/j.jvs.2005.09.025
Despite the suggestion of recent randomized trials that
the risk associated with EVAR is less than standard open
repair, concerns regarding EVAR durability remain.3,4 The
development of late graft migration and endoleaks occurs
in up to 30%,5,6 and are most likely responsible for the
persistent risk of aneurysm rupture occurring in up to 1%
annually after EVAR.5,7 Suprarenal fixation with bare wire
stents has been proposed as a method for improving proximal fixation, thus allowing endovascular repair of aneurysms with complex neck morphology or short proximal
necks. Furthermore, creation of a more stable proximal
fixation may lead to a decrease in late complications, including graft migration, endoleak formation, and aneurysm
rupture.
The risk of crossing the renal vessels remains uncertain,
however. Because of the nature of EVAR, these patients are
already at considerable risk for developing renal complications. In addition, many patients have diabetes mellitus or
renal insufficiency, making them at even higher risk. Renal
insufficiency after EVAR may be as high as 20%, and the
causes are likely multifactorial, including a combination of
contrast, mechanical, and atheroembolic sources.8 Preoperative evaluation routinely exposes patients to contrast dye
during computed tomography (CT) or, less commonly,
catheter angiography.
In addition, during placement, self-expanding grafts
are often partially deployed in the suprarenal position and
19.e1
19.e2 Parmer and Carpenter
JOURNAL OF VASCULAR SURGERY
January 2006
Table I. Inclusion and exclusion criteria
Proximal infrarenal neck
ⱖ15 mm length
ⱕ60° angle
26-mm maximum diameter
18-mm minimum diameter
AAA of ⱖ4.0 cm diameter or rapidly growing AAA
Iliac diameter of ⱖ7 mm on at least one side
Dispensable inferior mesenteric artery
Preservation of at least one hypogastric artery
Iliac seal zone of ⱖ1.5 cm
No pregnancy
Candidate for open AAA repair
Serum creatinine level ⱕ1.7 mg/dL
Willingness to comply with follow-up schedule
No bleeding disorders
Life expectancy ⬎2 years
No connective tissue disorders
AAA, Abdominal aortic aneurysm.
then pulled down the aorta into the final position, potentially dislodging aortic debris and resulting in atheroemboli
into the renal vessels. In fact, renal infarction rates as high as
19% have been documented during EVAR.9 Many devices
also use balloon fixation of the proximal graft that may
temporarily occlude the renal vessels, potentially resulting
in thrombosis, embolus, or dissection. The safety of then
placing a bare wire stent across the renal vessels is concerning.
Although the effect of suprarenal fixation with bare
stents has been investigated, most studies had included
small patient populations and have yielded limited conclusive data.10-15 To date, there has been no controlled study
of the topic. Most published reports compare devices of
different configurations, materials, and deployment strategies, making it even more difficult to come to any sound
conclusion.9,16-20 In addition, many of these studies have
used custom-made devices. With the availability of next
generation and commercially available US Food and Drug
Administration (FDA)-approved devices, these comparisons are now obsolete.
The purpose of this comparative analysis was to evaluate the effect of suprarenal fixation on renal function by
comparing homogeneous patient populations receiving
EVAR grafts from a single manufacturer that are identical
in design and delivery method, except for utilizing either
suprarenal or infrarenal fixation.
METHODS
Two hundred eighty-three patients underwent EVAR
with the Powerlink (Endologix, Inc, Irvine, Calif) unibody
bifurcated graft in the setting of two pivotal, multicenter
FDA trials. Data collected during these trials was retrospectively reviewed. Between July 2000 and March 2003, 192
patients underwent EVAR with infrarenal fixation, and 91
patients received grafts with suprarenal fixation between
October 2001 and September 2004. Each center acquired
approval from its Institutional Review Board for Human
Fig 1. The Powerlink bifurcated endovascular aneurysm repair
device. Comparison of the infrarenal fixation device (left) and the
device using suprarenal fixation (right).
Subject Investigations, and informed consent was obtained
from all patients before graft placement.
The inclusion and exclusion criteria were identical
for each trial (Table I). Except for fixation scheme,
suprarenal or infrarenal, the endografts are identical in
design (Fig 1), which has been described in detail previously.21 The main body of the endoskeleton consists of a
single 0.016-inch wire constructed of a cobalt chromium
alloy that is woven into a double spine, without joints or
welds. The suprarenal fixation component incorporates a
bare cage portion 22 mm in length consisting of six wire
segments along the circumference and is a continuation
of the endoskeleton. It does not use barbs or hooks, but
relies on radial force for proximal fixation. Both grafts
use identical delivery methods.
For each patient, baseline demographic data, blood
pressure, and serum creatinine levels were recorded upon
enrollment. Postoperative monitoring consisted of a physical examination, blood pressure measurement, and CT
angiography at 1, 6, and 12 months, and then annually.
Serum creatinine (SCr) levels were obtained at the discretion of the treating physician early in the trials and have
been subsequently incorporated into the routine surveillance during the suprarenal trial. For comparison of the
immediate and delayed effects of suprarenal fixation on
renal function, each group was subdivided into preoperative, perioperative (1 to 7 days), or postoperative (⬎7 days)
groups. To compensate for weight and age differences,
creatinine clearance (CrCl) for each time period was calculated using the Cockcroft-Gault formula: CrCl ⫽ (140 –
age) ⫻ weight/(SCr ⫻ 72). To adjust for female gender a
multiplication factor of 0.85 was applied.22 Complete SCr
and postoperative CT data were available in 147 of 192
JOURNAL OF VASCULAR SURGERY
Volume 43, Number 1
Parmer and Carpenter 19.e3
Table II. Patient characteristics
Age (years)
Mean
Range
Male gender (%)
Hypertension (%)
Coronary artery disease (%)
Renal insufficiency (%)
Diabetes mellitus (%)
Infrarenal
n ⫽ 147
Suprarenal
n ⫽ 79
73 ⫾ 7
52-88
91.2
64.6
46.9
10.2
13.6
73⫾9
52-91
87.3
69.6
50.6
8.9
21.5
P
.881
.366
.465
.676
.818
.135
Table III. Renal outcomes
Infrarenal (%) Suprarenal (%)
Intraoperative contrast
volume (mL)
Renal events
Stenosis/stent
Infarction
Occlusion
Renal impairment*
Baseline renal
insufficiency†
Contrast volume (mL)
Hemodialysis
30-day mortality
186 ⫾ 83
10 (6.8)
3
4
3
15 (10.2)
4 (26.7)
184 ⫾ 86
1 (0.7)
2 (1.4)
182 ⫾ 79
3 (3.8)
3
0
0
6 (7.6)
0
130 ⫾ 56
0
0
P
.77
.55
.634
.263
.212
1
.543
*Defined as elevation in serum creatinine by ⱖ30% and ⬎1.5 mg/dL.
†
Defined as preoperative serum creatinine ⬎1.5 mg/dL.
(77%) IR patients and in 79 of 91 (87%) SR patients. These
patients were used for data analysis.
Baseline renal insufficiency was defined as a preoperative SCr ⬎1.5 mg/dL. Renal impairment was defined as an
increase in SCr ⬎30% and an absolute value ⬎1.5 mg/dL
or the need for hemodialysis. Adverse renal events were
determined by CT and clinical chart review and included
the presence of renal infarction, progressive renal artery
stenosis, renal stent placement, and renal artery occlusion.
Data analysis. Data were expressed as mean and standard deviation. Comparison of continuous variables was
made by using the Student’s t test for independent variables. Categoric variables were compared with the Fisher’s
exact test. Differences were considered significant if the
two-tailed P value was ⬍0.05.
RESULTS
Demographics. The IR and SR groups were well
matched (Table II). There was no statistically significant
difference between groups in the prevalence of comorbid
conditions. Mean follow-up was 11.9 ⫾ 14.9 months for
IR fixation and 7.3 ⫾ 8.9 months for SR fixation. The
volume of contrast delivered intraoperatively was 186 ⫾ 83
mL for IR and 182 ⫾ 79 mL for SR fixation and was similar
between groups (P ⫽ .770) (Table III). The perioperative
30-day mortality was also similar for IR and SR fixation at
1.4% and 0% (P ⫽ .543).
Creatinine and creatinine clearance. Mean SCr decreased during the perioperative period with both IR (1.12
⫾ 0.31 mg/dL to 1.08 ⫾ 0.45 mg/dL, P ⫽ 0.269) and SR
(1.13 ⫾ 0.30 mg/dL to 1.06 ⫾ 0.28 mg/dL, P ⫽ .06)
fixation, although the differences did not reach statistical
significance (Table IV). Comparison of postoperative SCr
with preoperative levels revealed that mean SCr increased
significantly in IR (1.33 ⫾ 0.71 mg/dL, P ⬍ .0001) and
SR groups (1.26 ⫾ 0.34 mg/dL, P ⫽ .002). There were no
significant differences in SCr between IR and SR groups
during the preoperative (P ⫽ .893), perioperative (P ⫽
.607), or postoperative (P ⫽ .344) periods.
To determine whether the elevation in SCr was durable, a subgroup analysis was performed for those patients
with follow-up of ⬎12 months. In this population of 27 SR
and 67 IR patients, SCr remained significantly elevated
from baseline with IR (1.28 ⫾ 0.63 mg/dL, P ⫽ .001) and
SR (1.24 ⫾ 0.31 mg/dL, P ⫽ .047) fixation; however, it
was not significantly different between groups. A similar
pattern was noted when changes in CrCl were compared,
further confirming the alterations in renal function seen
with SCr (Table IV).
Renal impairment occurred in 15 IR patients (10.2%)
and six SR patients (7.6%), which was not statistically
different (P ⫽ .634) (Table III). There were no differences
in the volume of intraoperative contrast delivered among
those who developed renal impairment and those who did
not in IR (186 ⫾ 83 vs 184 ⫾ 86 mL, P ⫽ .952) or SR (182
⫾ 79 vs 130 ⫾ 56 mL, P ⫽ .150) groups. Hemodialysis was
required in one patient (0.7%) who had received a graft
utilizing IR fixation, with no significant difference between
groups (P ⫽ 1.00).
Preoperative renal insufficiency has been associated
with worse outcomes.10,17,18 To investigate this in our
patient population, a subgroup analysis of patients with
preoperative renal insufficiency (SCr ⬎1.5 mg/dL) was
performed. No patients in the SR group developed postoperative renal impairment, but four IR patients (26.7%) had.
This difference was not statistically significant (P ⫽ .263)
(Table III).
Renal events. Adverse renal events occurred in 10
patients (6.8%) with IR fixation compared with three
(3.8%) with SR fixation (Table III). This difference was not
statistically significant (P ⫽ 0.550). In the IR group, three
patients required stent placement, one for progressive renal
artery stenosis and two for partial coverage of the renal
artery from graft malpositioning during EVAR (Table V,
online only). Renal infarction was noted in four patients
with IR fixation, three occurring in the early postoperative
period, one of which was due to the intentional intraoperative coverage of the accessory renal artery. Renal artery
occlusion occurred in three IR patients between 6 and 12
months postoperatively, all of which were in accessory renal
arteries; only one resulted in radiographically significant
infarction. The SR patients had three events: two were
progressive stenoses being followed without intervention,
and one patient required a renal artery stent during EVAR
JOURNAL OF VASCULAR SURGERY
January 2006
19.e4 Parmer and Carpenter
Table IV. Effects on renal function and blood pressure
Creatinine (mg/dL)
Preoperative
Perioperative (1-7 days)
Postoperative (⬎7days)‡
Creatinine clearance (mL/min)
Infrarenal
Pⴱ
Suprarenal
Pⴱ
P†
Infrarenal
Pⴱ
Suprarenal
Pⴱ
P†
1.12 ⫾ 0.31
1.08 ⫾ 0.45
1.33 ⫾ 0.71
.269
⬍.0001
1.13 ⫾ 0.30
1.06 ⫾ 0.28
1.26 ⫾ 0.34
.06
.002
.893
.607
.344
75 ⫾ 28
82 ⫾ 29
67 ⫾ 25
.036
.0005
78 ⫾ 29
79 ⫾ 31
66 ⫾ 28
.862
.002
.365
.453
.923
Systolic blood pressure (mm Hg)
Preoperative
Perioperative (1-7 days)
Postoperative (⬎7days)‡
ⴱ
Diastolic blood pressure (mm Hg)
ⴱ
Infrarenal
P
Suprarenal
P
P
Infrarenal
Pⴱ
Suprarenal
140 ⫾ 22
131 ⫾ 20
139 ⫾ 18
.0002
.359
141 ⫾ 20
131 ⫾ 18
141 ⫾ 16
.0015
.986
.817
.994
.270
78 ⫾ 11
67 ⫾ 11
77 ⫾ 11
⬍.0001
.329
77 ⫾ 11
66 ⫾ 11
77 ⫾ 10
†
Pⴱ
P†
.819
.429
.352
.831
*Compared with preoperative values.
†
Comparison between infrarenal and suprarenal treatment groups.
‡
Mean follow-up: infrarenal, 11.9 ⫾ 14.9 months; suprarenal, 7.3 ⫾ 8.9 months.
owing to graft malpositioning. No renal infarction or renal
artery occlusion occurred in the SR group.
Blood pressure. To evaluate any physiologic effect of
increased SCr and renal events, a comparison of systolic
(SBP) and diastolic (DBP) blood pressure was made for
each time period (Table IV). During the perioperative
period, both IR and SR patients had significant decreases in
SBP and DBP. Over the long term, however, SBP returned
to baseline, and there was no significant difference in either
IR (140 ⫾ 22 mm Hg to 139 ⫾ 18 mm Hg, P ⫽ .359) or
SR (141 ⫾ 20 mm Hg to 141 ⫾ 16 mm Hg, P ⫽ .986)
groups compared with preoperative values. Similar changes
were seen with DBP in IR (78 ⫾ 11 mm Hg to 77 ⫾ 11
mmHg, P ⫽ .329) and SR (77 ⫾ 11 mm Hg to 77 ⫾ 10
mm Hg, P ⫽ .819) patients. There were no statistically
significant differences in SBP or DBP between IR and SR
patients during the preoperative (SPB, P ⫽ .817; DBP, P ⫽
.429), perioperative (SBP, P ⫽ .994; DBP, P ⫽ .352), or
postoperative (SBP, P ⫽ 0.270; DBP, P ⫽ .831) periods.
DISCUSSION
Endovascular abdominal aortic aneurysm repair is gaining widespread popularity among the medical and lay communities. Despite the heightened interest in this technique,
up to one third of all patients remain ineligible, as do half of
those at highest risk for open repair. Recent studies have
confirmed that the perioperative risk of EVAR is less than
with standard open repair,3,4,6 but concerns regarding durability and long-term safety remain.5-7 The development
of endoleaks or graft migration occurs in up to 30%, most of
which occur as a result of failure at the proximal fixation
site.5,6,23,24 Several factors likely contribute to these failures. Whereas the suprarenal aorta remains stable in diameter, the proximal infrarenal neck dilates over time after
EVAR, weakening the seal in this area.23,25,26 In addition,
short proximal aortic necks24 and ⬎40° angulation27 have
been implicated in graft migration and endoleak formation.
Suprarenal fixation by using bare stents has been proposed to increase patient eligibility and prevent late com-
plications. Recent data with long-term follow-up suggest
that SR fixation decreases late graft migration and endoleak
formation26 and may prevent complications due to aortic
neck angulation.28 The impact of crossing the renal vessels
with stents is uncertain, however.
Studies using in vitro and animal models have shown
that a reduction in flow or vessel area may result, especially
in the presence of more than one stent strut crossing the
orifice29 or the development of neointimal hyperplasia on
the stent struts.30 Further, Birch et al31 established in the
porcine model that stent configuration and the material
from which the stent is constructed may also significantly
affect renal outcomes.
Data to suggest the safety of suprarenal fixation during
EVAR have been accumulating but have not been conclusive (Table VI). These studies show that postoperative renal
dysfunction occurs in 2.6% to 29.9% of patients after EVAR
with SR fixation.10-15,17,18,20,32-34 In those studies that
compared SR results with IR fixation, most have demonstrated no significant difference between the two types of
fixation for the development of postoperative renal dysfunction.15,18,20 In one of the larger studies, however, Alric
et al17 showed in 169 patients with an 18-month follow-up
that postoperative renal impairment occurred in 17.2% of
SR patients, which was significantly worse than the IR
group (16.4%) (P ⫽ .04).
The development of adverse renal events, including renal
infarction, stenosis, or renal artery occlusion, occurs in 2.1% to
19% of patients after EVAR with SR fixation.9-16,18,19,32-34
Although most studies failed to detect a significant difference
between SR and IR fixation,15,16,18,19,33 Bockler et al9 reviewing their data on 202 patients who underwent EVAR
with SR fixation, with a mean follow-up of 37 months,
demonstrated that 39 patients (19%) developed renal infarction in the SR group compared with 17 in the IR group
(3.7%) (P ⬍ .00001).
In addition to conflicting results arising from two of the
larger studies to date, most published reports have included
small patient numbers from single-center experiences, mak-
JOURNAL OF VASCULAR SURGERY
Volume 43, Number 1
ing it difficult to come to any solid conclusions. Furthermore, these reports have typically evaluated data from
multiple endografts that are very different in materials,
design, and deployment technique, making these comparisons even less optimal.
Unlike previous studies, the present study compares
grafts that are identical except for fixation technique (Fig).
The SR and IR groups were well matched, attesting to the
similarities in the selection process for each trial (Table II).
The prevalence of comorbid conditions, including coronary artery disease, baseline renal insufficiency, diabetes
mellitus, and hypertension, were similar to previously reported series.15,18
In this study, SCr improved in both the SR and IR
groups in the immediate perioperative period, likely representing the aggressiveness with which these patients were
hydrated in an effort to minimize contrast nephropathy.
With long-term follow up, however, both groups developed progressive renal dysfunction compared with the preoperative levels. Mean SCr significantly increased with both
IR (1.12 ⫾ 0.31 mg/dL to 1.33 ⫾ 0.71 mg/dL, P ⬍
.0001) and SR (1.13 ⫾ 0.30 mg/dL to 1.26 ⫾ 0.34
mg/dL, P ⫽ .002) fixation (Table IV). There were no
differences in SCr between SR and IR fixation during any
time period. An identical trend in renal function was noted
after compensating for weight, age, and gender by calculating the CrCl, further validating the findings of progressive renal dysfunction in both groups (Table IV).
These findings are consistent with previous reports15,19,20 that also showed decline of renal function over
time. Alsac et al20 recently published their data comparing
the Zenith (Cook Diagnostic, Bloomington, IN) and Talent (World Medical Manufacturing Corp, Sunrise, Fla)
devices with the AneuRx device (Medtronic, Santa Rosa,
Calif) in 137 SR patients with a mean follow-up of 12.2
months. Although there was no difference between SR and
IR patients in the development of postprocedural renal
impairment (IR, 25.9%; SR, 29.9%; P ⫽ .46) or postoperative CrCl (IR, 61.7 mL/min; SR, 64.9 mL/min; P ⫽
.26), postoperative CrCl was significantly worse in both IR
(69.3 to 61.7 mL/min, P ⬍ .01) and SR groups (71.7 to
64.9 mL/min, P ⬍ .03) compared with preoperative values. This amounted to an approximate 10% decrease in
CrCl in both the IR and SR patients within the first year
after EVAR.
It has been proposed that these findings likely result
from the cumulative effect of repeated contrast exposures
during routine graft surveillance.15,19 To limit this effect,
the use of magnetic resonance angiography or duplex ultrasonography has been suggested as an alternative to CT
angiography and should be considered, especially in those
at high risk for developing contrast induced nephropathy.8,15,19 Furthermore, for high-risk patients requiring
repeated contrast studies, acetylcysteine35 or sodium bicarbonate36 alone or in combination have been shown to
decrease the adverse consequences of contrast and should
be used.
Parmer and Carpenter 19.e5
Despite progressive renal dysfunction in both groups as
a whole, only 15 IR (10.2%) and six SR patients (7.6%)
developed significant renal impairment, and in only one
patient (0.7%) in the IR group was hemodialysis required.
Furthermore, in those who developed renal impairment,
there was no difference in contrast administration between
the IR and SR groups (184 ⫾ 86 mL vs 130 ⫾ 56 mL, P ⫽
.212). These data seem to confirm that there is no significant difference in the impact of SR fixation on renal function compared with IR fixation.
The incidence of adverse renal events, including progressive renal artery stenosis, renal stent placement, renal
artery occlusion, or renal infarction, were uncommon in
either group and were not statistically different between
groups (Table III). This is in contrast to the previous study
by Bockler et al,9 where a significant increase in infarction
rate in patients receiving SR fixation vs IR fixation was
noted. As they used a variety of grafts, it is difficult to
determine why exactly they had such a high rate of renal
infarction. Their report noted higher rates of renal infarction in balloon-expandable grafts,9 which have been proposed as a risk factor for the development of renal complications, specifically renal infarction, and might be at least
partly responsible for their findings.8
Limitations of this study include it being a multicenter, nonrandomized study in which the analysis was
performed in a retrospective manner. As a result, selection and reporting biases are likely to occur; however,
the use of identical inclusion and exclusion criteria
should limit this effect. Also, serum creatinine was used
in this study as the marker of renal function as it is a
readily obtainable value that has been used consistently
when evaluating renal function after repair of abdominal
aortic aneurysms. Because of the insensitivity of this
method, an attempt to compensate for weight, gender,
and age was made by calculating CrCl using the Cockcroft-Gault method, realizing this formula may overestimate glomerular filtration rate by 16%.37 As both groups
were treated similarly, however, the trends between
groups and temporally should have been maintained
despite using these measures.
Although direct measurements are more sensitive in
monitoring renal function and include perfusion scintigraphy34 or urinary creatinine clearance, they are expensive
and difficult to obtain consistently in the trial setting and
were not performed routinely. In addition, few renal events
were detected, raising the possibility of lacking the sensitivity needed to detect a difference between groups and
risking a type II error.
This study relied entirely on the use of CT angiography
with reconstructed images to evaluate renal artery stenosis.
The use of routine duplex ultrasonography scans to demonstrate flow disturbances has been suggested and may
have allowed for more sensitive detection of flow-limiting
stenosis not seen on CT imaging.12-15
Despite these limitations, however, this is the only
study to date, to our knowledge, to evaluate the effects of
suprarenal fixation on renal function by comparing grafts
19.e6 Parmer and Carpenter
that are identical in every aspect except for fixation scheme.
This should eliminate many of the differences due to graft
design, materials, or deployment techniques, thus providing a more accurate measure of the renal effects from
suprarenal fixation compared with infrarenal fixation than
those previously published.
CONCLUSION
Suprarenal fixation appears to be comparable to infrarenal fixation and does not lead to a significant increase in
acute renal events, renal impairment, or alterations in blood
pressure. Patients undergoing aneurysm repair with either
suprarenal or infrarenal fixation devices tend to have progressive renal dysfunction over time. Further studies will be
required to determine what long-term effects suprarenal
fixation may have on the progression of renal artery stenosis
and renal function.
We thank Catherine Doorly and Gita Ghadimi for their
efforts in the preparation of this report.
AUTHOR CONTRIBUTIONS
Conception and design: SSP, JPC
Data collection: SSP
Analysis and interpretation: SSP, JPC
Writing the article: SSP
Critical revision of the article: SP, JPC
Final approval of the article: JPC, SSP
Statistical analysis: SSP
Overall responsibility: SSP, JPC
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aneurysms: the EUROSTAR experience. European Collaborators on
Stent/graft techniques for aortic aneurysm repair. J Vasc Surg 2000;
32:739-49.
8. Carpenter JP, Fairman RM, Barker CF, Golden MA, Velazquez OC,
Mitchell ME, et al. Endovascular AAA repair in patients with renal
insufficiency: strategies for reducing adverse renal events. Cardiovasc
Surg 2001;9:559-64.
JOURNAL OF VASCULAR SURGERY
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9. Bockler D, Krauss M, Mansmann U, Halawa M, Lange R, Probst T, et
al. Incidence of renal infarctions after endovascular AAA repair: relationship to infrarenal versus suprarenal fixation. J Endovasc Ther 2003;10:
1054-60.
10. Walker SR, Yusuf SW, Wenham PW, Hopkinson BR. Renal complications following endovascular repair of abdominal aortic aneurysms. J
Endovasc Surg 1998;5:318-22.
11. Kichikawa K, Uchida H, Maeda M, Ide K, Kubota Y, Sakaguchi S, et al.
Aortic stent-grafting with transrenal fixation: use of newly designed
spiral Z-stent endograft. J Endovasc Ther 2000;7:184-91.
12. Lobato AC, Quick RC, Vaughn PL, Rodriguez-Lopez J, Douglas M,
Diethrich EB. Transrenal fixation of aortic endografts: intermediate
follow-up of a single-center experience. J Endovasc Ther 2000;7:
273-8.
13. Bove PG, Long GW, Shanley CJ, Brown OW, Rimar SD, Hans SS, et al.
Transrenal fixation of endovascular stent-grafts for infrarenal aortic
aneurysm repair: mid-term results. J Vasc Surg 2003;37:938-42.
14. Cowie AG, Ashleigh RJ, England RE, McCollum CN. Endovascular
aneurysm repair with the Talent stent-graft. J Vasc Interv Radiol 2003;
14:1011-6.
15. Lau LL, Hakaim AG, Oldenburg WA, Neuhauser B, McKinney JM,
Paz-Fumagalli R, et al. Effect of suprarenal versus infrarenal aortic
endograft fixation on renal function and renal artery patency: a comparative study with intermediate follow-up. J Vasc Surg 2003;37:1162-8.
16. Kramer SC, Seifarth H, Pamler R, Fleiter T, Buhring J, SunderPlassmann L, et al. Renal infarction following endovascular aortic
aneurysm repair: incidence and clinical consequences. J Endovasc Ther
2002;9:98-102.
17. Alric P, Hinchliffe RJ, Picot MC, Braithwaite BD, MacSweeney ST,
Wenham PW, et al. Long-term renal function following endovascular
aneurysm repair with infrarenal and suprarenal aortic stent-grafts. J
Endovasc Ther 2003;10:397-405.
18. Cayne NS, Rhee SJ, Veith FJ, Lipsitz EC, Ohki T, Gargiulo NJ 3rd,
et al. Does transrenal fixation of aortic endografts impair renal function?
J Vasc Surg 2003;38:639-44.
19. Surowiec SM, Davies MG, Fegley AJ, Tanski WJ, Pamoukian VN,
Sternbach Y, et al. Relationship of proximal fixation to postoperative
renal dysfunction in patients with normal serum creatinine concentration. J Vasc Surg 2004;39:804-10.
20. Alsac JM, Zarins CK, Heikkinen MA, Karwowski J, Arko FR, Desgranges P, et al. The impact of aortic endografts on renal function. J
Vasc Surg 2005;41:926-30.
21. Carpenter JP. Multicenter trial of the PowerLink bifurcated system for
endovascular aortic aneurysm repair. J Vasc Surg 2002;36:1129-37.
22. Cockcroft MH, Gault DW, Prediction of creatinine clearance from
serum creatinine. Nephron 1976;16:31-41.
23. Conners MS 3rd, Sternbergh WC 3rd, Carter G, Tonnessen BH,
Yoselevitz M, Money SR. Endograft migration one to four years after
endovascular abdominal aortic aneurysm repair with the AneuRx device: a cautionary note. J Vasc Surg 2002;36:476-84.
24. Sampaio SM, Panneton JM, Mozes G, Andrews JC, Noel AA, Kalra M,
et al. AneuRx device migration: incidence, risk factors, and consequences. Ann Vasc Surg 2005;19:178-85.
25. Sonesson B, Malina M, Ivancev K, Lindh M, Lindblad B, Brunkwall J.
Dilatation of the infrarenal aneurysm neck after endovascular exclusion of
abdominal aortic aneurysm. J Endovasc Surg 1998;5:195-200.
26. Sternbergh WC 3rd, Money SR, Greenberg RK, Chuter TA. Influence
of endograft oversizing on device migration, endoleak, aneurysm
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27. Sternbergh WC 3rd, Carter G, York JW, Yoselevitz M, Money SR.
Aortic neck angulation predicts adverse outcome with endovascular
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28. Robbins M, Kritpracha B, Beebe HG, Criado FJ, Daoud Y, Comerota
AJ. Suprarenal endograft fixation avoids adverse outcomes associated
with aortic neck angulation. Ann Vasc Surg 2005;19:172-7.
29. Liffman K, Lawrence-Brown MM, Semmens JB, Sutalo ID, Bui A,
White F, et al. Suprarenal fixation: effect on blood flow of an endoluminal stent wire across an arterial orifice. J Endovasc Ther 2003;10:
260-74.
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stents covering the renal arteries ostia: an animal study. J Vasc Interv
Radiol 1997;8:77-82.
31. Birch PC, Start RD, Whitbread T, Palmer I, Gaines PA, Beard JD. The
effects of crossing porcine renal artery ostia with various endovascular
stents. Eur J Vasc Endovasc Surg 1999;17:185-90.
32. Burks JA J, Faries PL, Gravereaux EC, Hollier LH, Marin ML. Endovascular repair of abdominal aortic aneurysms: stent-graft fixation across
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33. Greenberg RK, Chuter TA, Lawrence-Brown M, Haulon S, Nolte L.
Analysis of renal function after aneurysm repair with a device using
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open surgical repair. J Vasc Surg 2004;39:1219-28.
34. Grego F, Frigatti P, Antonello M, Lepidi S, Ragazzi R, Iurilli V, et al.
Suprarenal fixation of endograft in abdominal aortic aneurysm treatment: focus on renal function. Ann Surg 2004;240:169-78.
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Zidek W. Prevention of radiographic-contrast-agent-induced reductions in renal function by acetylcysteine. N Engl J Med 2000;343:
180-4.
36. Merten GJ, Burgess WP, Gray LV, Holleman JH, Roush TS, Kowalchuk GJ, et al. Prevention of contrast-induced nephropathy with sodium bicarbonate: a randomized controlled trial. JAMA 2004;291:
2328-34.
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accurate method to estimate glomerular filtration rate from serum
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Submitted Jun 22, 2005; accepted Sep 13, 2005.
APPENDIX 1. Endologix investigators for the infrarenal device
Center
Principal investigator
University of Pennsylvania, Philadelphia, Penn
Cleveland Clinic, Cleveland, Ohio
Arizona Heart Institute, Phoenix, Ariz
Mayo Clinic and Foundation, Rochester, Minn
Southern Illinois University School of Medicine, Springfield, Ill
University of Chicago, Chicago, Ill
Morristown Memorial Hospital, Morristown, NJ
Barnes-Jewish Hospital, St. Louis, Mo
Greenville Hospital, Greenville, SC
Mercy Medical Center, Des Moines, Iowa
Harbor-UCLA, Los Angeles, Calif
Cardiac Thoracic & Endovascular Therapies, S.C., Peoria, Ill
Vascular and Transplant Specialists, Norfolk, Va
North Central Heart Institute, Sioux Falls, SD
Oklahoma Cardiovascular Research Group, Oklahoma City, Okla
Jeffrey P. Carpenter, MD
Timur Sarac, MD
Edward B. Dietrich, MD
Peter Gloviczki, MD
Kim J. Hodgson, MD
James McKinsey, MD
Amit V. Patel, MD
Gregorio A. Sicard, MD
Eugene M. Langan, MD
James R. Skinner, MD
Rodney A. White, MD*
James B. Williams, MD
Robert Gayle, MD
Michael J. Bacharach, MD
Robert M. Kipperman, MD
*Trial principal investigator
APPENDIX 2. Endologix investigators for the suprarenal device
Center
Principal investigator
University of Pennsylvania, Philadelphia, Penn
Cleveland Clinic, Cleveland, Ohio
Arizona Heart Institute, Phoenix, Ariz
Mayo Clinic and Foundation, Rochester, Minn
Southern Illinois University School of Medicine, Springfield, Ill
University of Chicago, Chicago, Ill
Morristown Memorial Hospital, Morristown, NJ
Barnes-Jewish Hospital, St. Louis, Mo
Greenville Hospital, Greenville, SC
Mercy Medical Center, Des Moines, Iowa
Harbor-UCLA, Los Angeles, Calif
Cardiac Thoracic & Endovascular Therapies, S.C., Peoria, Ill
Vascular and Transplant Specialists, Norfolk, Va
North Central Heart Institute, Sioux Falls, SD
Oklahoma Cardiovascular Research Group, Oklahoma City, Okla
Jeffrey P. Carpenter, MD
Timur Sarac, MD
Edward B. Dietrich, MD
Peter Gloviczki, MD
Kim J. Hodgson, MD
James McKinsey, MD
Amit V. Patel, MD
Gregorio A. Sicard, MD
Eugene M. Langan, MD
James R. Skinner, MD
Rodney A. White, MD*
James B. Williams, MD
Robert Gayle, MD
Michael J. Bacharach, MD
Robert M. Kipperman, MD
*Trial principal investigator
JOURNAL OF VASCULAR SURGERY
January 2006
19.e8 Parmer and Carpenter
Table V. Renal events and associated clinical effect on renal function and blood pressure
Study
group
Suprarenal
(n ⫽ 79)
1
Event
Stenosis
2
Stenosis
3
Stenosis/stent
Infrarenal
(n ⫽ 147)
1
Infarction
2
Occlusion
3
Infarction
4
Stenosis/stent
5
Stenosis/stent
6
Occlusion
7
Stenosis/stent
8
Occlusion
9
10
Infarction
Infarction
HTN, Hypertension.
Details
Renal function
Blood pressure
Progression to severe right renal
artery stenosis at 24 month
follow-up
Progression to severe left renal
artery stenosis at 24 month
follow-up
Right renal artery stent placed
intraoperatively for
procedural related stenosis
Early increase in creatinine
⬎30%, stable at 1.7-1.8
mg/dL
No change (1.0-1.1 mg/dL)
No change in baseline HTN
No change (1.0-1.3 mg/dL)
Early improvement of HTN
Left renal infarction at 2
months
Left accessory renal artery
occlusion at 12 months with
associated renal infarction
Right renal infarction at 1
month
Right renal stent placed
intraoperatively for
procedural related stenosis
Left renal stent place early
postoperatively for procedural
related stenosis and renal
ischemia
Right accessory renal artery
occlusion at 6 months
Progression to severe stenosis of
right renal artery requiring
stent
Right accessory renal artery
occlusion with cortical
thinning at 6 months
Left renal infarction at 1 month
Left renal infarction due to
intraoperative coverage of left
accessory renal artery
No change (0.9-1.4 mg/dL)
No change (1.2-1.4 mg/dL)
Acute worsening of HTN,
controlled by 12 months
No change in baseline HTN
No change (0.9 mg/dL)
No change
No change (0.9-1.2 mg/dL)
No change in baseline HTN
Early increase in creatinine
⬎30%, stable at 1.9-2.2
mg/dL
No change
Unknown
No change in baseline HTN
No change (1.7-1.9 mg/dL)
No change in baseline HTN
No change (1.1-1.4 mg/dL)
No change
No change (2.0-2.3 mg/dL)
Unknown
No change in baseline HTN
No change
New onset HTN over 24
month follow-up
JOURNAL OF VASCULAR SURGERY
Volume 43, Number 1
Parmer and Carpenter 19.e9
Table VI. Summary of published series evaluating the renal effects of suprarenal fixation
Study author
Publication
year
SR group
(n)
Endograft (s)*
used
Comparison
group
Comparison
group (n)
Alric et al17
Alsac et al20
Bockler et al9
Bove et al13
Burks et al32
Cayne et al18
Cowie et al14
Greenberg et al33
Grego et al34
Kichikawa at al11
Kramer et al16
Lau et al15
Lobato et al12
Parmer, Carpenter
Surowiec et al19
2003
2005
2003
2003
2002
2003
2003
2004
2004
2000
2002
2003
2000
2005
2004
169
137
202
30
95
69
38
351
47
18
69†
32
35
79
82
2,5,6,9,11
2,4,6
1,2,3,5,6,7,9,10
4
4,11
2,3,4,5,6,10
4
2
2,4
11
2,3,4,5,6,7,8
2,6
4,5,11
1
2,3,4,5,6
Walker et al10
1998
22
5,9,11
IR
IR
IR
—
—
IR
—
Open
—
—
IR
IR
—
IR
IR
Open
IR
146
135
461
—
—
61
—
79
—
—
124‡
55
—
147
64
65
142
SR, Suprarenal; IR, infrarenal; RI, renal insufficiency; NS, Not significant.
*Key to endografts used: 1. (Powerlink, Endologix, Inc., Irvine Calif); 2. (Zenith, Cook Diagnostic, Bloomington, Ind); 3. Excluder (W.L. Gore and
Associates, Flagstaff, Ariz); 4. Talent (World Medical Manufacturing Corp, Sunrise, Fla); 5. Vanguard (Boston Scientific/Meadox, Natick, Mass); 6.
AneuRx (Medtronic, Santa Rosa, Calif); 7. Lifepath (Edwards Lifesciences LLC, Irvine Calif); 8. Corvita (Boston Scientific, Natick, Mass); 9. Chuter; 10.
Ancure (Guidant Corp., Indianapolis, IN); 11. Custom-made grafts.
†
Renal events defined as I (infarction), S (stenosis/stent), O (occlusion).
‡
Reported as renal arteries at risk.
Table VI. Summary of published series evaluating the renal effects of suprarenal fixation
Mean follow-up
(months)
18
12.2
37
28.5
25
17
12.5
12
16
14
⬎12
12
11
7.3
23
⬍30 days
SR group post-op
RI % (comparison group %)
SR group renal
events % (control %)
Renal events
type†
Significance SR group vs
comparison group (P)
17.2 (16.4)
29.9 (25.9)
—
20
3.3
10.1 (11.5)
2.6
16 (12)
10.6
5.6
—
9.4
14
7.6 (10.2)
—
—
18
—
—
19 (3.7)
17
2.1
5.8 (1.6)
2.6
4.8 (2.5)
2.1
5.6
8.7 (5.6)
9.4 (0)
2.9
3.8 (6.8)
7 (7)
—
23
—
—
I, O
S, O
I
I
I
S, I, O
S
S
I
I, O
S
S
I, O
.04
NS
⬍.00001
—
—
NS
—
NS
—
—
NS
NS
—
NS
NS
O
—