Late occlusion of renal arteries after endovascular repair of abdominal aortic aneurysms by suprarenal fixation of stent grafts
(Portuguese
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Ricardo Aun,1 Fernando Tavares Saliture Neto,2 Alex Lederman2, Hilton Waksman2, Lucia Mendes Pinto3
1.
Director, Centro Paulista de Cirurgia Vascular (CPCV), São
Paulo, SP, Brazil.
2. Associate physicians, CPCV, São Paulo, SP, Brazil.
3. Ph.D. Physician, Hospital Albert Einstein. São Paulo,
SP, Brazil.
Correspondence:
Centro Paulista de Cirurgia Vascular
Av. Albert Einstein, 627, 11° andar, Sala 1109
CEP 05651-901 - São Paulo, SP, Brazil
Tel.: +55 11 3742.1365/3742.5117/3747.3109
Fax: +55 11 3747.3507
E-mail: aun@einstein.br or aun@uol.com.br
ABSTRACT
Objective:
The aim of this study is to present three cases of late complications of renal arteries.
Patients
and method: From November 1998 to February 2005, 121 patients with abdominal aortic aneurysm were treated by endovascular repair. In 81 cases, the suprarenal fixation of stent grafts was performed, and 40 patients were submitted to the infrarenal fixation of stent grafts. Post-operative follow-up computed tomography scans were performed within 1, 6 and 12 months, and annually after the first year. Ninety-seven (80.1%) patients were followed up according to this protocol, with no loss to follow-up. Of these, 33 (34%) received infrarenal graft fixation, and 64 (66%), suprarenal graft fixation.
Results:
There were complications in the renal arteries of three patients who had received supra-renal graft fixation. Left renal artery occlusion was identified by computed tomography scans in two patients, who developed systemic arterial hypertension in the postoperative, which was not present before the surgery. A 12-month control computed tomography scan identified a left renal artery partial stenosis in the third patient, who remained asymptomatic. Patients who developed hypertension were submitted to renal revascularization.
Conclusions:
Supra-renal graft fixation is a feasible maneuver. In order to make it a safe procedure, surgeons must control the patient's evolution of renal arteries through imaging methods and clinical follow-up.
Key-words:
renal artery, abdominal aortic aneurysm, vascular prosthesis.
J
Vasc Br 2005;4(2):143-8
The suprarenal
fixation of stent grafts to repair abdominal aortic aneurysms (AAA)
is widely used, since it increases the indications for endovascular
treatment of AAA, due to the neck length.1-3
However, it is discussed that this technique is pointed out by some
as a cause of occlusive lesions of renal arteries at medium- and long-term,
by partial or complete obstruction, besides renal infarctions, renovascular
arterial hypertension, and even renal insufficiency with increase in
serum levels of creatinine.3-6
When early
and immediate, it is usually a consequence of technical maneuvers by
blockage of the renal artery ostium by the covered part of the stent
graft. Other causes are the immediate complications of the atheroma
plaque, a consequence of the balloon dilatation, or due to intimal lesion
in abrupt maneuvers with the graft introducer. They can be identified
intraoperatively or in postoperative controls.
When late,
it can be a consequence of the progression of the partial ostium occlusion
of the renal artery by the metallic alloy stent with thrombosis and
intimal hyperplasia, or due to a remodeling of the aneurysmal sac.
The literature
is rich in presenting reports of early complications of this kind, however
late occlusions of the renal artery lesion are less cited, as well as
therapeutic conducts, which are not discussed enough.7,8
The aim
of this article is to present three cases in which there were late occlusive
complications of the renal artery after suprarenal fixation of aortic
stent grafts, identified months after the treatment, as well as the
diagnostic methods used and the therapeutic conduct and its causes.
PATIENTS
From November 1998 to February 2005, 121 patients with AAA were treated by endovascular repair by fixation of aortic stent grafts at Centro Paulista de Cirurgia Vascular. The suprarenal fixation of stent grafts was used in 81 patients. All the other 40 patients were treated with infrarenal fixation of stent grafts. Postoperative follow-up abdominal angiotomography was performed within 1, 6 and 12 months, and annually thereafter. Ninety-seven (80.1%) patients were followed up according to this protocol, with no loss to follow-up. Of these, 33 (34%) received infrarenal graft fixation, and 64 (66%) suprarenal graft fixation.
RESULTS
We did
not observe complications of renal arteries in the follow-up of the
33 patients who received infrarenal aortic graft fixation.
Regarding
the other 64 patients, in two of them there was complete occlusion of
unilateral renal artery in a 2-year follow-up (Vanguard® stent graft)
(Figure 1) and 6-month follow-up (Talent® stent graft) (Figure 2), respectively.
The other patients, in a 1-year control, presented stenosis of the left
renal artery around 50% in the origin (Talent® stent graft) (Figure
3). The first two patients had arterial hypertension, which was not
present preoperatively (Table 1).
 Figure
1 - Digital subtraction angiography showing occlusion of the right
renal artery origin (arrow).
Figure
2 - Computed tomography of the case 2 patient, showing a reduction
in the left kidney size and the renal artery without contrast.
Figure
3 - Angiotomography of case 3, showing stenosis of the left renal
artery origin.
Table
1 - List of patients in which a complication in the renal artery
was postoperatively identified
 |
| Patient
|
Age
|
Stent
graft |
Renal
artery lesion |
Detection
time |
Repair
technique |
|
| RMG
|
76
|
Vanguard®
|
occlusion
|
2
years |
splenorenal |
| APM
|
64
|
Talent®
|
occlusion
|
6
months |
iliac
and renal and |
| ACCS
|
68
|
Talent®
|
stenosis
|
1
year |
clinical
treatment |
|
In hypertensive
patients (cases 1 and 2), alterations in the renal scintigraphy were
detected, with reduction in the perfusion and the indication of renal
revascularization.
In the
first patient, terminolateral splenorenal bypass was performed, with
adequate revascularization maintained patent up to the present moment,
according to the confirmation by angiotomography (Figure 4), with normalized
renal function and without the need for antihypertensive medication.
In the second patient, we chose to perform a reconstruction from the
iliac artery with PTFE graft (Figure 5) and termino-terminal anastomosis
of renal artery. This patient had a normalization of serum levels of
urea and creatinine, but had a slight hypertension, controlled by nifedipine
10 mg.
Figure
4 - Case 1: angiotomography with splenorenal reconstruction to the
left (arrow).
Figure
5 - Case 2: angiotomography with three-dimensional reconstruction
with revascularization of the left kidney (iliac and renal graft with
PTFE).
Patient
number 3 presented partial renal artery stenosis, verified by angiotomography,
with around 50%. This patient, who was previously hypertensive, maintained
the same preoperative level. Renal function studies were normal, and
the Doppler ultrasound (Figure 6) and renal scintigraphy did not show
alteration of flow or perfusion. In this situation, we chose the clinical
follow-up and are waiting for the next tomographic control.
Figure
6 - Case 3: bilateral renal scintigraphy showing symmetry in the
perfusion stage.
DISCUSSION
The suprarenal
fixation of aortic stent grafts reduces the incidence of type I endoleak
and allows a wider application of the method.1-3
However, side effects concerning renal complications are presented by
some as limitations for its use.5
Some authors
point out an increase in the occurrence of renal infarction, more probability
of renal artery occlusion, and fast evolution of pre-existing stenosis
of these arteries when such procedure is used. Bockler et al., in 663
patients with AAA, used the suprarenal fixation in 202. Tomographies
were performed after 10, 90, and 365 days. In 2.6% (17 patients), there
was loss of renal function, and the need for dialysis in two patients.
Unintentional renal ischemia was detected in 39 (19%) out of the 202
patients with suprarenal fixation and in 17 (3.7%) patients with infrarenal
fixation.5 Lobato et al., in 35 patients
who received an indication for transrenal fixation due to short neck
or for repair of type I endoleaks, did not observe occlusive complications,
but recommended vigilant observation for patients who present renal
artery stenosis greater than 60%, since one patient presented progression
of stenosis and severe arterial hypertension, which was repaired by
transluminal angioplasty.6
Some authors
analyzed the factors related to the suprarenal fixation separately,
comparing them with factors related to the infrarenal fixation. Grego
et al.9 consider the suprarenal fixation
to be efficient, but the fall in renal function occurred in 10% of patients.
Marin et
al.3 reported a higher incidence of type
I endoleaks in patients who received infrarenal fixation of stent grafts.
On the other side, there was a higher number of unilateral renal occlusions
when the suprarenal fixation was used.
The worsening
of renal function after an endovascular repair of AAA may also be related
to a pre-existing renal insufficiency and to the use of contrast.10-12
A failure
in the angiographic visualization at the moment of the implant is the
first mechanism suggested for the occurrence of these complications.
In this situation, the covered portion of the stent graft can partially
or even completely occlude the renal artery, and this fact can remain
unknown. The transluminal angioplasty can be used during the first procedure,
once the lesion is known.13,14 A distal
traction of the stent graft with the aid of the guide-wire can be an
option. However, this maneuver cannot be adopted for stent grafts that
have micro-hooks for fixation.
The second
mechanism we consider to be important for the occurrence of renal artery
lesion is the handling of stent grafts with the stent uncovered and
opened. This maneuver consists of opening one or two rings of the stent
graft and, with an injection of contrast visualizing the renal arteries,
choosing the best position for the stent graft. We do not perform it
anymore, since it can lead to endothelial trauma and aortic atheroma.
The balloon inflation to adjust the stent graft in the aneurysm neck
may also lead to a fracture in the aortic plaque and to a lesion of
the renal artery ostium.
The third
mechanism that may lead to renal artery occlusion is the stent graft
remodeling, as a consequence of the aneurysm reduction, which occurs
with Vanguard® stent grafts.
We understand
that, when the renal artery stenosis or occlusion is symptomatic, whether
with alteration of renal function or occurrence of renovascular hypertension,
the renal revascularization should be recommended.15
In this series, we chose the operative repair of the renal artery occlusion
in two out of three patients.
In the
first case, the tomographic image was responsible for detecting the
renal artery occlusion. This patient presented a mild arterial hypertension,
concurrently to the 2-year tomographic control (Figure 1). We chose
the operative repair aiming at preserving the renal function, and the
splenorenal bypass was chosen since it is an operation performed with
autologous material that has a high patency rate.15
In the
second case, we chose to perform the iliac and renal reconstruction
with PTFE®. This patient presented sudden onset acute arterial hypertension
difficult to control, 6 months after the repair of AAA. There was also
an increase in creatinine, around twice the reference value. Both parameters
were normalized after the arterial reconstruction.
Finally,
in the third patient, who was already preoperatively hypertensive, despite
the detection of stenosis of around 50% by angiotomography of the left
renal artery, we concluded that revascularization was not necessary
yet, since the duplex flowmetry ultrasound, the scanning with technetium,
and the serum level of creatinine were normal.
Thus, despite
the complications of the transrenal fixation of aortic stent grafts,
we observed the benefit brought by an increase in indications for cases
of short neck. Nevertheless, inappropriate handling of the graft introducer
should be avoided and care should be taken when inflating the balloon,
in order to avoid fracture of the aortic plaque and of the renal artery
ostium. The careful observation of the angiographic control and the
strict follow-up make the technique feasible. Early identification of
cases of renal insufficiency and renovascular hypertension allows a
favorable progression.
CONCLUSION
The suprarenal aortic graft fixation is useful. However, in order to make it a safe procedure, surgeons must control the patient's evolution of renal arteries through imaging methods and clinical follow-up.
REFERENCES
1.
Verhoeven EL, Prins TR, Tielliu IF, et al. Treatment of short-necked
infrarenal aortic aneurysm with fenestrated stent-grafts: short-terms
results. Eur J Vasc Endovasc Surg 2004;27:477-83.
2.
Morrisey NJ, Faries PL, Teodorescu V, Hollier L, Marin ML. Transrenal
bare stents in endovascular treatment of abdominal aortic aneurysms.
J Invasive Cardiol 2002;14:36-40.
3. Marin ML, Parsons RE, Hollier LH, et al. Impact of
transrenal aortic endograft placement on endovascular graft repair of
abdominal aortic aneurysms. J Vasc Surg 1998;28:638-46.
4. Kalliafas S, Albertini JN, Macierewcz J, et al. Incidence
and treatment of intraoperative technical problems during endovascular
repair of complex abdominal aortic aneurysms. J Vasc Surg 2000;31:1185-92.
5. Bockler D, Krauss M, Mannsmann U, et al. Incidence
of renal infarctions after endovascular AAA repair: relationship to
infrarenal versus suprarenal fixation. J Endovasc Ther 2003;10:1054-60.
6.
Lobato AC, Quick RC, Vaughn PL, Rodriguez-Lopez J, Douglas M, Diethrich
EB. Transrenal fixation of aortic endografts: intermediate follow-up
of single-center experience. J Endovasc Ther 2000;7:273-8.
7. Burks JA, Faries PL, Gravereaux EC, Hollier LH, Marin
ML. Endovascular repair of abdominal aortic aneurysms: stent-graft fixation
across the visceral arteries. J Vasc Surg 2002;35:109-13.
8. Bove PG, Long GW, Shanley CJ, et al. Transrenal fixation
of endovascular stent-graft for infrarenal aortic aneurysm repair: mid-term
results. J Vasc Surg 2003;37:938-42.
9. Grego F, Frigatti P, Antonello M, et al. Suprarenal
fixation of endograft in abdominal aortic aneurysm treatment: focus
on renal function. Ann Surg 2004;240:169-78.
10.
Alric P, Hinchliffe RJ, Picot MC, et al. Long-term renal function following
endovascular aneurysm repair with infrarenal and suprarenal aortic stent-grafts.
J Endovasc Ther 2003;10:397-405.
11.
Suworiec SM, Davies MG, Fegley AJ, et al. Relationship of proximal fixation
to postoperative renal dysfunction in patients with normal serum creatinine
concentration. J Vasc Surg 2004;39:804-10.
12.
Kramer SC, Seifarth H, Pamler R, et al. Renal infarction following endovascular
aortic aneurysm repair: incidence and clinical consequences. J Endovasc
Ther 2002;9:98-102.
13.
Lau LL, Hakaim AG, Oldenburg WA, 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.
14.
Abraham CZ, Chuter TA, Reilly LM, et al. Abdominal aortic aneurysm repair
with the Zenith stent graft: short to midterm results. J Vasc Surg 2002;36:217-24.
15.
Estenssoro AEV. Hipertensão renovascular com oclusão total
crônica da artéria renal: nefrectomia ou revascularização?
[tese]. São Paulo: Faculdade de Medicina da Universidade de São
Paulo; 1999.
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