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February 2011 Supplement
The EXCLUDER-Centervasc Registry
A preliminary report from a 10-year efficacy and durability study on EVAR.
By Arno Von Ristow, MD; Bernardo Maddiere, MD; and Alberto Vescovi, MD
The natural history of abdominal aortic aneurysms (AAAs) is well known. If left untreated, rupture and death is the expected outcome. Endovascular AAA repair (EVAR) was introduced by Parodi et al in 1990, primarily to treat high-risk patients, many of whom were unable to overcome the risks of open surgery.1 After proving to be feasible in that decade, surgeons' worries were concentrated on the efficacy of the procedure, with special concern regarding the durability of the implanted devices and their ability to exclude AAAs.
Our experience with the GORE EXCLUDER Device (W. L. Gore & Associates, Flagstaff, AZ) began in December 1999. Through the end of 2010, 188 patients were treated at Centervasc (Rio de Janeiro, Brazil) with the EXCLUDER Device, with follow-up to 10 years. This is an independent prospective registry, and it has not been funded by either Gore or their distributor in Brazil. All endografts and hospital expenses have been paid for by either the patients themselves or by their health care supplier. All procedures have been performed under the supervision of the senior author, Dr. von Ristow.
INDICATIONS, PLANNING,
AND METHOD OF TREATMENT
Indications for treatment were based on the presence of
symptoms and size of the AAA, as internationally accepted.
Preoperative workup included carotid and coronary
noninvasive studies in all patients, and operative risk
was assessed according to the American Society of
Anesthesiology. In the first 6 years of this study, EVAR was
indicated only for high-risk patients, with strict criteria.
Later on, as confidence was acquired with the EXCLUDER
Device, EVAR was progressively indicated for lower-risk
patients.
Although always based in computed tomography (CT), imaging considerably improved during the study period. Angiography with marked catheters played an important role in our early experience. Currently, multislice CT angiography (CTA) with multiplanar reconstructions has totally supplanted other methods.
The vascular surgery residents at Centervasc, assisted by senior staff members, performed all procedural planning. In this study, AAA cases with proximal necks of adequate length and an inner diameter ranging from 20 to 28 mm were enrolled. Thin thrombus at the neck, up to 25% of the circumference, was not considered to be a contraindication. Neck angle up to 60o was accepted. A diameter of at least 22 mm for the distal neck and a maximum of 18 mm for the iliac arteries was required, with a distal sealing zone of at least 10 mm.
The implantation was performed through surgical access to the femoral arteries. In the early cases, the EXCLUDER Device was released from its constraining covering using a quick deployment. With increased experience, release was performed slowly under full visual control. The techniques we employed have been published in the Brazilian literature and by Minion and Jordan, respectively.2-5
The device has been extensively used in cases of tortuous iliac arteries, often along with extra-stiff guidewires to straighten them (Figure 1). In Brazil, many patients have small stature. The ability to use the EXCLUDER Device with crossed limbs was applied to prevent undesired hypogastric occlusion. Ectatic common iliac arteries (up to 18 mm) were treated with bellbottom limbs (Figure 2). We have given extreme attention to the preservation of at least one hypogastric artery. Aneurysms of both iliac arteries with involvement of the bifurcation were usually treated with unilateral hypogastric exclusion plus surgical hypogastric revascularization in this series. In sexually active men, bilateral hypogastric preservation was the rule (Figure 3). In eight cases of nondialytic renal insufficiency, EVAR was performed without the use of iodinated contrast media. Fluoroscopy and duplex scan were used to guide the implant in these cases.2 Whenever the diameter of the femoral artery allowed the concomitant introduction of a 7-F sheath, with the 12-F sheath used to implant the EXCLUDER Device contralateral limb in place, we filled the aneurysmal sac with fragmented gelfoam sponge to reduce the occurrence of type II endoleaks.
FOLLOW-UP
Patients were seen for follow-up consultations at 1, 6,
and 12 months and yearly thereafter. Follow-up in the first
5 years of the study was based on physical examination and
CT. Since 2005, our protocol has been based on an annual
physical examination, duplex scan, and plain radiography of
the abdomen and pelvis, complemented eventually by CTA.
Early (30-Day) Results
Technical success was achieved in all cases, with no operative
death. Thirty-day mortality was 1.6% (three patients had
blood dyscrasia, pulmonary embolism, and myocardial infarction, respectively). One type IA endoleak was observed.
There was no conversion to open surgery (Table 1).
Long-Term Results
One hundred eighty-five patients survived to 30 days and
have undergone prospective follow-up (Table 2). One late
migration in an angulated neck was observed, with development
of a type IA endoleak, as well as one type IB endoleak
due to enlargement of the iliac artery. Both endoleaks were
treated by endovascular means—the type IA endoleak by
transforming the bifurcation in a conical uni-iliac graft, with
occlusion of the contralateral common iliac artery and
femorofemoral crossover grafts. The type IB endoleak was
treated with exclusion of the hypogastric artery with coils
and implantation of an extension to the external iliac artery.
Type II endoleaks were detected in nine patients (4.77%):
two presented with spontaneous occlusions, two were
treated by translumbar coiling, and five are under watchful
observation, with no aneurysm growth. No structural failure
(type III endoleak) has been observed.
We observed four patients (2.25%) that, after showing shrinkage of the sac, showed slow aneurysmal growth without a detectable endoleak, implying endotension. All of these patients underwent implantation before 2003. This occurrence is probably related to the expanded polytetrafluoroethylene permeability of the early device. To date, no sacs have enlarged to a size requiring further treatment.6
In this series, we have not observed late renal impairment related to the presence of the endograft. Thrombosis of limbs were rare (1.6%), and only one required treatment. No main graft thrombosis occurred. There was one case of graft infolding in the external iliac artery. It has been observed for 3 years without thrombosis of the limb. Late graft infection occurred in two cases (1.1%) and both were due to contamination of the graft by contiguous infection by Mycobacterium tuberculosis of the left psoas muscle in very debilitated octogenarians. Both patients did not survive extra-anatomical axillary bifemoral grafting plus endograft explantation, although this is not representative of the overall findings because these were the only two aneurysm-related deaths in the series (Table 3). Aside from these two cases, no late conversion was necessary. Integrity and long-term stability, even in hostile anatomy, has been the rule with the EXCLUDER Device. We have not observed barb fractures or other device integrity issues.
DISCUSSION
Results of the EXCLUDER Device for treating AAA have
been widely published.6-8 Several improvements were made
to the EXCLUDER Device during the study period. Most
important is the incorporation of a new low-permeability
interior layer while maintaining the same luminal and abluminal
stent graft surfaces, the addition of a 31-mm main
body size, and iliac extensions up to 20 mm in diameter. The
development of techniques that allow gradual and precise
proximal graft release expanded the application of this
unique device, which to date remains the only one that is
mounted on a catheter, a feature that allows its use in severe
iliac angulations without kinking.
In this series, we did not observe late renal impairment, which has been reported with the use of grafts with suprarenal fixation.9 As well as efficacy, the durability of AAA exclusion has been a challenge to all grafts used for EVAR. Figure 4 shows an EXCLUDER Device that was implanted in a AAA with a 60° angulated neck and is perfectly stable 7 years after implantation. Long-term comparative outcomes after EVAR have been published, and all favor the EXCLUDER Device as an effective and durable device.10-14 This 10-year follow-up study confirms outstanding results, situating the EXCLUDER Device in a privileged standpoint.
CONCLUSION
After 188 EVAR procedures performed from 1999 to 2010
using the GORE EXCLUDER Device that were followed-up
prospectively up to 10 years, we conclude that this device is
durable and effective for the treatment of AAAs.
Acknowledgements: Drs. José M. Cury, Cleoni Pedron, and Marcus Gress, former members of Centervasc, performed a minor portion of the procedures in this study.
Arno von Ristow, MD, is Associate Professor of Vascular Surgery, Pontifícia Universidade Católica of Rio de Janeiro, and Director of Centervasc, Clínica Sorocaba in Rio de Janeiro, Brazil. He has disclosed that he has received educational grants from the W. L. Gore & Associates distributor in Brazil. Dr. Ristow may be reached at +55 21 99866870; drarno@centervasc.com.br.
Bernardo Massière, MD, is Clinical Instructor of Vascular Surgery of the Pontifícia Universidade Católica of Rio de Janeiro, and Associate Vascular Surgeon at Centervasc in Rio de Janeiro, Brazil. He has disclosed that he holds no financial interest in any product or manufacturer mentioned herein.
Alberto Vescovi, MD, is Clinical Instructor of Vascular Surgery of the Pontifícia Universidade Católica of Rio de Janeiro, and Associate Vascular Surgeon at Centervasc in Rio de Janeiro, Brazil. He has disclosed that he holds no financial interest in any product or manufacturer mentioned herein.
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