Oriainal articles
`
`Transfemoral Intraluminal Graft
`Implantation for Abdominal Aortic
`Aneurysms
`
`J.C. Parodi, MD*, J.C. Palmaz, MD.', H.D. Barone, PhD, Buenos Aires,
`Argentina, and San Antonio, Texas
`
`This study reports on animal experimentation and initial clinical trials exploring the
`feasibility of exclusion of an abdominal aortic aneurysm by placement of an
`intraluminal, stent-anchored, Dacron prosthetic graft using retrograde cannulatlon of
`the common femoral artery under local or regional anesthesia. Experiments showed
`that when a balloon-expandable stent was sutured to the partially overlapping ends
`of a tubular, knitted Dacron graft, friction seals were created which fixed the ends of
`the graft to the vessel wall. This excludes the aneurysm from circulation and allows
`normal flow through the graft lumen. Initial treatment in five patients with serious
`co-morbidities is described. Each patient had an individually tailored balloon diam-
`eter and diameter and length of their Dacron graft. Standard stents were used and the
`diameter of the stent-graft was determined by sonography, computed tomography,
`and arteriography. In three of them a cephalic stent was used without a distal stent.
`In two other patients both ends of the Dacron tubular stent were attached to stents
`using a one-third stent overlap. In these latter two, once the proximal neck of the
`aneurysm was reached, the sheath was withdrawn and the cephalic balloon inflated
`with a salinekontrast solution. The catheter was gently removed caudally towards
`the arterial entry site in the groin to keep tension on the graft, and the second balloon
`inflated so as to deploy the second stent. Four of the five patients had heparin
`reversal at the end of the procedure. We are encouraged by this early experience, but
`believe that further developments and more clinical trials are needed before this
`technique becomes widely used. (Ann Vasc Surg 1991 ;5:491-499).
`
`KEY WORDS: Graft-stent exclusions; grafts; abdominal aortic aneurysm; transfem-
`oral intraluminal grafts.
`
`Abdominal aortic aneurysm (AAA) has been rec-
`ognized since antiquity as a lethal pathologic pro-
`cess. As a result, the last 50 years of vascular
`surgery have seen a variety of attempts at cure of
`[I], external
`the condition. Intraluminal wiring
`
`From the Department of Vascular Surgery, Instituto
`Cardiovascular de Buenos Aires*, Buenos Aires, Argen-
`tina, and the Department of Radiology, University of
`Texast, San Antonio, Texas.
`Reprint requests: Dr. J.C. Parodi, Mercedes 4255, Cap.
`Fed. Buenos Aires, Argentina (1419).
`
`wrapping [2], and exclusion of the aneurysm by
`ligation have been tried and discarded in the past
`[3]. Experience with those showed that they did not
`offer durable protection from aneurysm rupture [4].
`Neither wrapping nor thrombosis of the aneurysm
`protected the patient from fatal rupture [5-71.
`Today, vascular surgeons are dealing with an
`increasingly aged population. These are persons in
`whom abdominal aortic aneurysms occur. Autopsy
`studies have placed the overall incidence of AAA
`disease between 1.8 and 6.6% [%lo]. Actual inci-
`dence of AAA is increasing with the aging of the
`
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`39 2
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`TRANSFEMORAL INTRALUMINAL GRAFT IMPLANTATION
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`ANNALS UE-
`VASCULAK S U K G t K Y
`
`Fig. 1. Artificial abdominal aortic aneurysm created
`by fusiform-shaped Dacron conduit.
`
`population 11 I]. In the 30-year period of study, the
`incidence of AAA was seen to rise threefold. Fur-
`thermore, aneurysm screening in select populations
`such as first-order relatives of patients with AAA or
`patients in cardiovascular clinics has shown that in
`select populations, the incidence of aneurysms may
`vary from 5% to 20% [12-141.
`Durable protection from aneurysm rupture began
`with DuBost [IS] who demonstrated that aortic
`replacement was an effective method of treatment.
`Prosthetic graft replacement is the treatment of
`choice for aortic aneurysms today. Elective repair
`is regularly performed with an operative mortality
`of under 5% with the expectation that long-term
`survival is markedly extended [ 16,171,
`Increasingly, vascular surgeons are encountering
`older patients with severe co-morbid conditions. These
`can increase operative morbidity and may even elevate
`mortality of aortic surgery to a figure in excess of 60%
`[Is]. With this in mind, new methods of aortic aneu-
`rysm exclusion deserve exploration. The following
`study reports on animal experimentation and initial
`clinical trials which explored the feasibility of exclusion
`of AAA by placement of an intraluminal, stent-an-
`chored, Dacron prosthetic graft using retrograde can-
`nulation of the common femoral artery under local or
`regional anesthesia.
`
`ANIMAL STUDIES
`Initial exploration of a solution to the problem
`involved in intraluminal graft placement was begun
`in 1976. Simultaneously, experiments progressed
`towards debulking the Dacron prosthesis so that it
`could be implanted through a miniaturized sheath,
`and modification of stents so that they could anchor
`the Dacron prosthetic material to aortic wall. Fi-
`nally, artificial AAAs were created in experimental
`
`Fig. 2. lntraluminal exclusion of artificial aneurysm by
`implanting Dacron tubular grafts by transfemoral route.
`Balloon expandable tents anchor graft to aortic wall.
`
`animals by replacing a segment of the infrarenal
`aorta with a fusiform-shaped, Dacron conduit (Fig.
`1). After creation of the artificial AAA in the
`experimental animal, experiments were completed
`by successfully excluding the aneurysm by implant-
`ing Dacron tubular grafts through the transfemoral
`route (Fig. 2) [19-211.
`Experimental study had shown that stents could
`replace surgical suture and could act as friction
`seals to fix ends of the graft to vessel wall. These
`friction seals were developed by creating a trans-
`lurninal graft-stent combination by suturing a Pal-
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`VOLUME 5
`NO 6 - 1991
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`TRANSFEMORAL INTRAL UMlNAL GRAFT IMPLANTATION
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`Fig. 3. Graft-stent combination is mounted on valvuloplasty balloon and placed under fluoroscopy through
`sheath introduced through femoral arteriotomy.
`maz, balloon-expandable stent" to the partially
`overlapping ends of a tubular, knitted Dacron graft.
`This was done so that the stent expansion would
`press the graft against the aortic wall, creating a
`watertight seal. Placement of the stent-graft assem-
`bly was planned to be done by actually mounting
`the assembly on a balloon angioplasty catheter.
`This would then be placed under fluoroscopy
`through a #14 French sheath introduced through a
`femoral arteriotomy (Fig. 3).
`Figures 4 and 5 show that the concept is correct.
`The graft-stent combination, when expanded by the
`balloon, can exclude the aneurysm from the circu-
`lation and allow normal flow through the graft
`lumen. Once the concept was proven that a Dacron
`graft could be delivered through a catheter and be
`firmly fixed in place by balloon-expandable stents,
`attention turned to human studies.
`This report details the initial treatment in five
`patients. A sixth patient treated by J.C. Palmaz is
`not reported here.
`
`contains the balloon catheter consisting of a #9
`French, polyethylene (PE) shaft and one or two PE
`valvuloplasty balloons, 3.5 cm in length, and either
`23 or 25 mm in diametert. The assembly contains
`either one or two aortic balloon-expandable stents,
`6 mm in diameter and 3.5 cm in length. These are
`stainless steel, modified Palmaz stents. A specially
`created. thin-walled, crimped, knitted, Dacron
`graft6 was sutured to the stents, overlapping one-
`third of the length of the stent**.
`In three patients, a cephalic stent was used with-
`out a distal stent (Fig. 2). In the two other patients,
`both ends of the Dacron tubular stent were attached
`to stents using one-third stent overlap. In these two
`cases, once the proximal neck of the aneurysm was
`reached, the sheath was withdrawn and the cephalic
`balloon inflated with a solution containing 50%
`saline and 50% nonionic contrast material. The
`balloon was kept inflated under low pressure to
`expand the folded graft. Finally, in those two cases
`with a double balloon, the catheter was gently
`moved caudally toward the arterial entry site in the
`groin to keep tension on the graft, and the second
`balloon was inflated so as to deploy the second
`
`GRAFT-STENT COMBINATION
`A Teflon, #22 French sheath, 45 cm in length
`with a hemostatic valve cldsure in the operator end
`
`*Johnson & Johnson Interventional Systems, Warren,
`N. J.
`
`'Mansfield Corporation, Boston, Massachusetts.
`§Barone Manufacturers, Buenos Aires, Argentina.
`**Barone Manufacturers, Buenos Aires, Argentina.
`
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`494
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`TRANSFEMORAL INTRALUMINAL GRAF?’ IMPLANTATIOR!
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`ANNA1 S Or
`VASCULAR SL~RGFRY
`
`Fig. 4. Arteriogram of aorta four weeks after replac-
`ing segment with artificial aortic aneurysm in dogs.
`
`stent. Thus, the prosthetic graft was anchored in
`place both proximally and distally.
`The procedure was terminated by performing an
`arteriogram after introducing an arteriographic
`catheter over the guidewire. After removal of the
`guidewire and overlying catheter, the arteriotomy
`in the femoral vessels was closed with 6-0 polypro-
`pylene suture. Because 10,000 units of heparin
`solution was given intravenously before graft place-
`ment, the heparin was reversed with the appropri-
`ate dose of Protamine sulfate at the conclusion of
`the procedure. Patients were routinely monitored in
`the coronary care unit, postoperatively.
`In the following cases, each patient had an indi-
`vidually tailored device. Both the diameter of the
`balloon and diameter and length of the Dacron graft
`were individualized. The stents themselves were
`standard and the diameter of the stent and graft
`combination was determined by data obtained from
`sonograrns, computed tomographic (CT) scans, and
`arteriograms. Stent size determined diameter of the
`balloon used to deploy the stent. Cardiopulmonary
`monitoring was done under cover of an antibiotic
`umbrella (1 gm Keflin, given intravenously).
`
`Fig. 5. Arterio ram of same dog after implanting
`graft-stent com%ination through right femoral artery.
`
`CASE HISTORIES
`
`Patient No. 1
`A 70-year-old man with severe chronic obstructive
`pulmonary disease complained of severe back pain
`caused by a 6 cm AAA (Fig. 6). Incidental note was made
`of bilateral lower extremity intermittent claudication. The
`patient refused a surgical procedure but did agree to enter
`the clinical trial. After explanation of the alternatives and
`expected complications, informed consent for the exper-
`imental procedure was obtained.
`The patient was prepared as if for standard surgical
`AAA resection. Under epidural anesthesia, the common
`femoral artery was freely dissected and mobilized. Arte-
`riography was then performed under fluoroscopy (Fig.7)
`and an Amplatz wire was placed in the descending
`thoracic aorta. An intraluminal graft was implanted on
`
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`VOLUME 5
`NO 6 - 1991
`
`TRANSFEMORAL INTRALUMINAL GRAFT 1MPLANTATION
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`Fig. 6. Computed tomographic scan of Patient Number 1.
`
`September 6, 1990. This patient had a hematoma in the
`right groin containing approximately 100 cc of blood. This
`was evacuated on the day of operation. In this instance,
`the initial heparin dose was not reversed following place-
`ment of the stent-graft combination.
`Note: Heparin anticoagulation was reversed in the
`following four cases and care was given not to admin-
`ister antiplatelet agents or Dextran to these patients.
`
`Patlent No. 2
`A 68-year-old man was admitted because of a 6 cm,
`pulsatile abdominal mass, confirmed to be an AAA. He
`volunteered to enter the clinical trial, and after informa-
`tion was given regarding alternative treatments and de-
`scription of complications, he gave written consent for
`the procedure. A single stent-graft combination was im-
`planted on September 6, 1990. During the procedure,
`there was an accidental displacement of the marking
`ruler. This reference, therefore, failed to identify the
`exact target area in which the stent would be placed. As
`a consequence, the stent was deployed 3 cm distal to the
`selected site. Therefore, the Dacron graft was overly long
`and the caudal end of the prosthesis lay within the right
`common iliac artery. This effectively excluded the con-
`tralateral iliac artery from the circulation. This was a
`patently unsatisfactory situation and the patient was
`taken to the operating room where a standard AAA
`resection was performed. Fortunately, he recovered from
`this procedure uneventfully. In surgery, it was found that
`the stent was firmly attached to the wall of the aorta
`which required resection.
`
`Patient No. 3
`A 63-year-old man was referred from the French Hos-
`pital in Buenos Aires where he had been admitted be-
`
`cause of an acute stroke. Computed tomographic scans
`had shown a massive, right hemispheric, hemorrhagic
`infarction. Two weeks following admission for treatment
`of this event while the patient was recovering satisfacto-
`rily, he experienced acute abdominal discomfort and
`increasing pain. A large, pulsatile mass in his abdomen
`enlarged rapidly, and he was transferred with the diagno-
`sis of AAA dissection. Because of his severe neurologic
`injury, a decision was made to use the transfemoral
`prosthetic graft implantation technique, and the proce-
`dure was done on November 11, 1990 after informed
`consent.
`Because only a proximal stent was used in this case,
`reflux was noted at the distal end of the prosthetic graft.
`The stent effectively closed the proximal intimal disrup-
`tion, the patient’s pain subsided, and the diameter of the
`aorta dramatically diminished. Follow-up at seven
`months has been completed, and reflux at the distal end of
`the graft is still noted. The reflux does not fill the false
`lumen of the dissection. Presumably, the intimal rent
`which initiated the dissection has been sealed (Figs. 6,7).
`
`Patient No. 4
`
`A 61 -year-old man was asymptomatic but was afllicted
`with a 6.5 cm AAA. He was a severe asthmatic with
`profound chronic obstructive pulmonary disease. He
`volunteered for the graft trial and the stent-graft combi-
`nation was implanted on January 3, 1991. Following
`placement of the prosthetic graft and proximal stent,
`reflux was noted at the distal end of the graft and a second
`stent was placed. Six months of follow-up have been
`completed. The aneurysm has not increased in size and is
`effectively excluded from the circulation with arterial
`continuity being established through the prosthetic graft
`and its double stent fixation.
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`496
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`ANNAI s w
`VASCULAR SLRCitRY
`
`Fi . 7. Aortography of Patient Number 1 depicting an
`inerarenal aneurysm.
`
`Patient No. 5
`A 62-year-old man was referred from the Argentinian
`province of Santa Fe. He had experienced multiple,
`recurrent episodes of atheromatous embolization to the
`lower extremities. In addition, he had severe and non-
`correctable coronary artery occlusive disease with a
`cardiac ejection fraction of less than 20%. Recent pulmo-
`nary edema had been treated successfully. A small, 3.8
`cm AAA was discovered and this was found to have a n
`irregular luminal surface, suggesting mural thrombosis.
`Cardiac echocardiography demonstrated an enlarged left
`ventricle without thrombus formation. No arrhythmias
`were found on Holter monitoring.
`The distal atheromatous embolization was treated with
`intraarterial infusion of prostaglandin E, (Prostin)*. After
`four days of arterial infusion, a marked improvement in the
`perfusion of the distal lower extremity was achieved. There-
`fore, on May 26. 1991, the graft-stent combination was
`implanted. In this case, a double stent was placed initially,
`thus sealing the proximal and distal ends of the prosthetic
`graft to aortic wall. There has been no recurrence of distal
`embolization since implantation of the device (Fig. 10).
`At this time, all five patients are doing well. The
`follow-up time has been 12 months in two patients, and
`nine, eight, and three months in the other three. All
`
`'Upjohn Company, Kalamazoo, Michigan.
`
`Fig. 8. Graft-stent combination with cephalic stent.
`
`patients have been studied by duplex Doppler color
`ultrasound and C T scans. Late arteriograms have been
`performed in two patients (Cases 1 and 3) (Fig. 9). As
`noted above in Case 3, persistent distal reflux has been
`noted at the distal end of the prosthetic graft. However,
`the dissection itself has been controlled and no attempt
`has been made to attach the distal end of the prosthesis.
`The size of the excluded AAA is considered to have
`decreased in three patients.
`
`DISCUSSION
`The study in experimental animals and in the five
`human subjects cited above suggests that transfem-
`
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`VOLUME 5
`NO 6 - 1Y91
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`TRANSFEMORAL INTRAL UMINAL GRAFT IMPLANTATION
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`Fig. 9. Aortography of Patient Number 1, 53 days after implantation of graft-stent combination.
`
`oral, intraluminal prosthetic graft placement can be
`achieved using balloon-expandable stent fixation of
`the prosthetic graft. The transfemoral approach
`allows placement of the prosthesis and exclusion of
`the AAA from the circulation under local or limited
`epidural anesthesia without the morbidity of a high,
`regional block, or general inhalation anesthetic.
`Lack of aortic cross-clamping and brief total aortic
`occlusion time allows graft exclusion of the aneu-
`rysm without cardiac compromise.
`Justification for the procedure is found in the fact
`that AAAs must be excluded from the circulation in
`order to prevent aneurysm rupture. In Szilagyi’s
`classic study [22], small, surgically untreated aneu-
`rysms were the cause of death in 29.5% of patients.
`Treatment of small AAAs has been shown to im-
`prove late survival [22]. Furthermore, in Darling’s
`much quoted study [23], 18.1% of 182 ruptured
`aneurysms were less than 5 cm in diameter. A more
`modern report by Cronenwett [24] suggests that
`AAAs as small as 4 cm in diameter can be associ-
`ated with a rate of rupture as high as 20% per year if
`
`hypertension is present. These facts have suggested to
`some that the presence, and not the size, of an AAA
`should be the indication for exclusion from the circula-
`tion. It is the smaller aortic aneurysm that lends itself to
`correction by this technique.
`The larger the aneurysm, the greater the risk of
`rupture, so resection and graft replacement have
`emerged as the treatment of choice for these le-
`sions. This is true even in high-risk patients with
`associated co-morbidity. Even non-correctable
`myocardial ischemia. cardiomyopathy, and pulmo-
`nary and renal insufficiency do not entirely con-
`traindicate graft replacement of the aortic aneu-
`rysms. They do, however, increase operative
`mortality. Other factors, when present, may in-
`crease the difficulty and therefore the morbidity and
`mortality of the procedure. These include the hos-
`tile abdomen with impenetrable peritoneal adhe-
`sions, multiple prior arterial reconstructive proce-
`dures, or abdominal wall stomas. Patients with such
`medical co-morbidities or with technical factors
`
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`TRANSFEMORAL INTRALUMINAL GRAFT IMPLANTAHON
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`ANNALS OF
`VASCULAR SURGERY
`
`remains to be shown. More important is the fact that
`graft dilation is more a postoperative finding than a
`clinical problem. In two patients in this study, fol-
`low-up has suggested that the excluded aneurysm and
`intraluminal thrombus exterior to the prosthetic graft
`appear to fibrose and diminish in diameter. Such re-
`traction is noted, and to date, no graft dilation has been
`seen.
`The question of patent lumbar arteries contribut-
`ing to continuing aneurysm expansion has not been
`solved by the present study. Admittedly, many
`lumbar arteries may have been occluded by the
`atherosclerotic aortic aneurysm wall or intraluminal
`thrombus. However, in some patients it is predict-
`able that lumbar arteries will remain patent and, in
`fact, the inferior mesenteric artery may also remain
`patent. Whether or not these patent vessels will
`contribute to continuing aneurysm expansion is
`unknown. Theoretically. occlusion of the lumbar
`arteries and mesenteric artery could be expected to
`follow intraluminal graft placement.
`Because AAAs frequently contain
`intraluminal
`thrombus, the possibility of distal embolization of such
`thrombus by intraluminal manipulation remains a
`threat. The fact that no apparent intraluminal thrombus
`embolized distally in the initial five cases does not
`exclude this complication as a possibility. As the Am-
`platz guidewire is relatively stif€, the graft-stent sheath
`is maintained in an access parallel to the aortic wall,
`and this may minimize dislodgement of thrombus from
`the wall of the aneurysm.
`The Palmaz stent has been shown to become
`covered with endothelium relatively rapidly. Thus,
`it becomes included in the wall of the artery in
`which it is placed. The natural history of the aortic
`wall proximal and distal to the aneurysm remains to
`be seen. Whether or not it will be the site of intimal
`hyperplasia is unknown [25,26].
`Certain anatomic characteristics of the aortic
`aneurysm must be present for the graft-stent device
`to be utilized. The aortic aneurysm should be asso-
`ciated with normal aortic wall proximally and dis-
`tally. Such normal aorta should be at least 3 cm in
`length proximally and at least 2 cm in length distally
`near the bifurcation. The iliac arteries should be
`patent or be suitable for balloon angioplasty. The
`#22 French sheath is large and the iliac arteries
`should be straight or nearly straight and not elon-
`gated or tortuous. Should such anatomic features be
`present, the potential advantages of transfemoral
`intraluminal graft placement are obvious. A lower
`cardiovascular, respiratory, and renal morbidity
`should decrease mortality. Furthermore, blood
`transfusions can be obviated and trauma to the
`periaortic and periiliac autonomic plexes will be
`avoided by the procedure.
`We are encouraged by the early expericnce but
`acknowledge that further developments are to be
`expected and more experience must be acquired
`
`Fig. 10. Graft-stent combination with both cephalic
`and caudal stent.
`
`increasing operative risk have, over the years,
`stimulated continuation of this study.
`As in all studies, experience with this small group
`of patients turns up questions as well as answers.
`Fortunately, an extensive follow-up of Palmaz stent
`placement has proven that no migration of the stent
`occurs [25,26].
`Transfemoral graft placement requires that the pros-
`thetic material be a compliant, knitted graft which is
`thn-walled. The tendency of such graft materials to
`dilate in the arterial stream is well known. However, in
`transfemoral graft placement, this material is placed
`within an intact, though dilated, aorta. Whether or not
`this graft inclusion technique will allow graft expansion
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`VOLUME 5
`NO 6 - 1991
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`TRANSFEMORAL INTRALLIMIIVAL GRAFT IMPLANTATION
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`before the procedure can be safely included in the
`armamentarium of vascular surgeons. Once the
`procedure reaches a greater degree of perfection,
`there is no doubt that patients who present a
`prohibitive risk of operation can be treated and their
`life expectancy extended.
`
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`Capdevila, Barcelona. Spain.
`20. PALMAZ JC, PARODI JC, BARONE HD, et al. Translum-
`inal bypass of experimental abdominal aortic aneurysm.
`Presented at 76th Scientific Assembly and Annual Meeting
`of RSNA. November 25-30, 1990. Summary.
`21. PARODI JC. PALMAZ JC, BARONE HD, et al. Translum-
`inal aneurysm bypass: experimental observations and pre-
`liminary clinical experiences. Presented at International
`Congress IV. Endovascular Therapies in Vascular Disease.
`Scottsdale, Arizona. February 1991, Summary.
`22. SZILAGYI DE, SMITH RF, DERUSO FI, et al. Contribu-
`tion of abdominal aortic aneurysmectomy to prolongation of
`life. Ann Surg 1966;164:676-699.
`23. DARLING RC, BREWSTER DC. Elective treatment of
`abdominal aortic aneurysm. World J Surg 1980;4:661-667.
`24. CRONENWETT JL, MURPHY TF, ZELENOCK GN, et al.
`Actuarial analysis of variables associated with rupture of small
`abdominal aortic aneurysms. Surgery 1985 ;98:47243.
`2.5. PALMAZ JC, RICHTER GM, NOELDGE G, et al. Intdumi-
`nal stents in atherosclerotic iliac artery stenosis: preliminary
`report of multicenter study. Radiology 1988;168:727-731.
`26. REES CR, PALMAZ JC, GARCIA 0, et al. Angioplasty
`and stenting of completely occluded iliac arteries. Radiology
`1989; 1 72:953-959.
`
`Commentary
`
`It has been said that the essence of great art is
`simplificution. In working out the details of trans-
`femoral exclusion of abdominal aneurysms from
`the aortic stream, Dr. Juan Parodi and his col-
`leagues have simplified aortic surgery. Thus, their
`work is truly artistic as well as scient$c.
`There is no doubt that the procedure achieves its
`purpose. Predictably, it will be offered at first to
`patients who are at prohibitive risk for conventional
`aortic surgery. As experience grows, it will be
`offered to patients who are good surgical risks,
`even those with aneurysms smaller than the ones
`conventionally requiring surgical repair. During
`this time, complications will occur, some of which
`are cited in this initial clinical experience. As every
`interventional procedure has its own complications,
`new problems will arise. Opposition to the proce-
`dure will he mounted. In vascular surgery no
`chunge for the better has occurred that wise and
`good men have not opposed. Now that this initial
`barrier is broached, new applications, including
`transluminal distal bypass are predictable. Such
`change is inevitable. It is, as Thoreau said, ‘‘ . . . a
`mirucle to contemplate; but it is a miracle which is
`taking place every minute.”
`
`John J. Bergan, M.D.
`LaJolla, California
`
`Page 9
`
`IPR2014-00100 Pat. Owner Ex. 2012
`Medtronic v. Marital Deduction Trust
`
`