Luis R. Leon, Jr., MD, RVT
University of Arizona
Aortic aneurysms are common in the elderly and a frequent cause of death. Their occurrence has recently increased due to screening, better imaging and longer life expectancies. Open surgical repair is still considered their mainstay of treatment. Endovascular stent-grafts have offered a less invasive and potentially safer therapy, avoiding the morbid-mortality associated with open repair.
I have cared for veterans throughout my career, a great challenge because they often present with advanced disease and comorbidities. Many veterans with aneurysms are not good candidates for open repair. Furthermore, aneurysmal involvement of major aortic branches often precludes standard stent use. To overcome these limitations, fenestrations or branches have been added to commercial stents. However, this technology at this time is only property of few centers of excellence. I believe that adding these modifications to our existing methodologies will significant impact the care that our patients receive.
Since the main focus of my activities is aortic aneurysm therapy, I planned visiting leaders in this field. I chose Drs. Chuter and Greenberg, who hold the largest experience with these devices in the United States (US). Additionally, I chose Drs. Anderson, Hartley and others in Australia. I also traveled to the Cook planning and manufacturing offices in Perth and Brisbane respectively. Lastly, I also visited Drs. Verhoeven and Prins in the Netherlands and Drs. Malina, Ivancev, Sonesson and others in Sweden.
UCSF - Dr. Chuter - July 31, 2007
Dr. Chuter had prepared the case of a 75 year-old lady with a type II thoracoabdominal aortic aneurysm. An iliac conduit in preparation for the current procedure was previously done given severe iliac atherosclerosis. Anesthesia placed an epidural drain for intraspinal pressure control. The procedure required simultaneous exposure of the left brachial artery and both common femoral arteries. This procedure is an ingenuous compilation of well-known endovascular techniques applied to aneurysm therapy with branched grafts, revascularizing the major visceral vessels with endovascular stents prior to their coverage. Once the aneurysm was successfully excluded, attention to the patient’s blood pressure was given to minimize spinal hypoperfusion, due to such a large area of covered aorta. The procedure lasted 6 hours; only 28 cc of dye and 111 minutes of fluoroscopy were required. The blood loss was 400 cc. The patient woke up neurologically intact, with palpable pedal pulses and with clear urine in adequate volumes. Dr. Chuterand his colleagues at that time had completed 26 branched endograft cases and stented about 150 native arteries, with striking patency rates. Lastly we discussed the management of the spinal drain, clinical and imaging follow-up. My first exposure to an impressive technique not widely available in the US.
Ashford Hospital - Adelaide - Dr. Anderson - March 25-31, 2008
By meeting Dr. Anderson, I had the chance to meet a pioneer in this field and to take a very close look of his busy practice. Their system works very different than mine: Anesthesiology is available for all cases in the Angiography suite. Patients are quite relaxed during the intervention. This room has the sterility required by an operating room, and Dr. Anderson has converted cases from endovascular to standard open in several occasions without problems. In fact, all aortic stents are placed in this suite. Rooms are ready in between cases in a few minutes only. They regularly use closure devices. Dr. Anderson does not currently train residents. He has about 6 radiology techs that alternate in between cases, most of them very experienced and knowledgeable of the next step always. His assistants hold wires, flush sheaths, and do routine steps of the procedures as a reflex. Bed availability of operating “theatre” or Angiography suite availability to book a case at any time do not seem to be a problem. I saw nurses bringing patients down to the Angiography suite for Dr. Anderson to see prior to their discharge without disturbing his procedural productivity. All those factors combined, but most importantly, due to Dr. Anderson’s extraordinary skills, result in very fast procedural and turnover time, with an ensuing enormous productivity. I suspect they do about 40 cases during a busy week, which ends up in about 1440 cases a year for a single practitioner, more than twice the productivity that our VA has. The cases I observed were mostly infrainguinal, but also visceral, cerebral and aortic. I learned some differences in the performance of these cases: a regular introducer needle is used in all cases and no micropunture kits; Heparin drips are started during the one-night hospital stay after endovascular interventions, which stops prior to discharge. A dose of LMWH is additionally given prior to discharge. Dr. Anderson and I deployed an iliac bifurcation device (IBD) under fluoroscopy, which had already expired. On the weekend, I enjoyed Dr. and Mrs. Anderson’s hospitality for lunch and dinner. This was an experience that, in spite of the lack of complex endografting cases, was enriching and eye opening.
Cook Medical Planning Offices/Hollywood Hospital - Perth - Drs. Hartley, Scott, Mwapataye - April 2-4, 2008
My visit was arranged by contacting Dr. Scott, a vascular surgeon in Perth. He is a vascular surgeon from Tasmania, the current president of the Australasia Society for Vascular Surgery. The following day, I visited the Cook Planning Offices, where I met the planning staff and Dr. David Hartley. With a background in radiography, he is the co-inventor of the Cook Zenith device. David’s major contribution to the device has been mostly on the delivery system (the delivery sheath is named: HLB system - Hartley, Lawrence and Brown). We discussed the device history and the current applications and technique for its deployment, and we went over details of the case that we were about to observe. Later I met with the manager of the planning division and we went over a typical design for a case of a complex aortic aneurysm repair. Then, I was taken to Hollywood Hospital, where Dr. Mwapataye was about to perform the IBD case, which required an IBD over the left iliac system, a converter over the right iliac system and a Flex graft. On Friday mornings, a conference is held where complex graft planning for the world is done. Theydiscussed challenging aortic aneurysm/dissection cases, sent to them for advice/planning/custom-made requests. It was an open venue for discussion as far as the feasibility or not of an endovascular approach, and what kind of device would be best suited for each particular case. It was interesting and somewhat foreign to me, given my unfamiliarity with the planning details involved in fenestrated or branched grafts.
Cook Offices - Brisbane - April 7, 2008
After my arrival to the Brisbane Technology Park, I got a tour of the administrative part of the building, and then proceeded to go to the manufacturing area. About 40 workers worked on making the stents from scratch. They are in charge of all the custom-made aortic stents for the world. Infrarenal stents come from Indiana, whereas the thoracic grafts come from Denmark and Scotland. The Brisbane office has a storage room for all raw materials: wires, stents, sheaths and everything needed for the assembly of these grafts. Workers in this area have no surgical background: most of them undergo in-situ training, anywhere from 3 weeks to 6 months depending on their individual ability to master sewing techniques. To enter these areas, semi-sterile technique is required. Here, a small piece of polyester is taken and sewn according to what has been required, to the end process. Several pieces of stents, Z-shaped, are welded into the fabric. Individual stitches using polypropylene are used to secure the fabric to the wires, utilizing surgical needle holders. From there, the sutured grafts go to quality control, where each stitch is analyzed under the microscope, to ensure its proper execution. Once this is done, all fenestrations, side-branches or other modifications are done until the graft goes to the sheathing area. Device assembly is hand-made for the most part. Sheaths and needles are also made from scratch. Then the stents are packed and wrapped, and from there they go to be sterilized, by applying ethyleneoxide to them in special containers. The gas is then neutralized using sulfuric acid and water, ending up in non-toxic polyethyleneglycol. They dry up under 40-degrees and then they are ready for shipping. Periodically, samples from all workers and materials used, are sent to the microbiology lab to ensure sterility. Infection control is 5 times stricter than what needs to be, to ensure proper sterile deliver of the devices.
Melbourne Hospital - Melbourne - Dr. Denton - April 7-9, 2008
This patient was a 74 year-old male with a small abdominal aortic aneurysm and bilateral common iliac artery aneurysms, significantly large on the right side. Dr. Denton had tried a right hypogastric artery embolization a few days prior, unsuccessfully due to iliac tortuosity. The plan that day was to coil embolize the same artery but through a left brachial approach, to place the IBD on the left iliac arteries, and to place a Flex infrarenal stent-graft to follow. The case required bilateral groin and left arm open exposure. The procedure went well, however the aortic bifurcation was sharply angulated, creating an acute kink and not allowing the covered stent destined to the hypogastric artery, to navigate through the kink and it was dislodged. After several attempts for up-and-over stent placement, decision was made to leave the IBD in place and cannulate the side arm to the hypogastric through a brachial approach, which was done without difficulties. A great bail-out solution for a case with severe tortuosity.
Groningen University - Groningen - Dr. Verhoeven - May 17 -23, 2008
A 6-hour workshop on fenestrated and branched grafts was held in Groningen, hosted by Drs. Verhoeven and Prins. The next morning we were taken to observe the case of a young male with an infrarenalaorto-bi-iliac aneurysm, with a funnel-shaped neck, who needed a branched endograft as well as bilateral IBDs. Then, we went to the “spectatorium”, a room for visitors to watch surgical interventions at the “operatiecentrum” with state-of-the-art audiovisual equipment. They deployed the fenestrated graft, cannulated the renal arteries and placed bilateral Jomed stents, deployed both IBDs and stented both hypogastric arteries, and completed it with deployment of a bifurcated endograft. A total of 12 endografts/stents were needed, placed in 3.5 hours, with excellent results. My second day involved getting acquainted with their vascular service, both in the OR and in the Angiographic suite. The following morning I attended Surgery Grand Rounds. I then observed a carotid endarterectomy done under TCD and EEG monitoring. Then we measured many complex anatomy cases to assess feasibility of a standard vs. more advanced grafts. Then we went to vascular conference, where cases that were coming to vascular clinic the following day were discussed. The next morning I observed an open AAA repair, where an aortobiiliac graft was placed transperitoneally.
Malmo University - Sweden - Dr. Malina - May 26-31, 2008
Dr. Malina and I attended their weekly vascular and endovascular section meeting. Their list of inpatients contained several aneurysm patients, especially ruptured. All together, excluding aortic dissections, they intervened in about 140 elective and ruptured aneurysms last year, mostly endovascularly. This service is a busy combined vascular surgeon-interventional radiology service. There are several vascular centers in Sweden, most importantly in Upsala, Lund, Stockholm and Malmo. The latter has done more aortic interventions than the other institutions combined. The meeting was attended by at least 20 people, among them: vascular surgeons, angiologists (vascular medicine equivalent), radiologists, nurses, fellows and students. To follow, I attended morning rounds, to see all patients that were discussed in the morning meeting. Then I visited their two endovascular suites, to which the hybrid suite in the OR is added for their use. To follow, we attended an informal lunch meeting where all staff members discussed general issues pertinent to their department as a unit. Then I observed an SFA recanalization and AVM embolization with ethanol (by Dr. Ivancev). Later Dr. Ivancev, myself and part of his staff analyzed CTs of patients with aortic dissections that were treated by their unit, as part of their research. I observed a case of a ruptured aneurysm treated with a stent, as well as a 9-hour case of a thoracoabdominal aortic aneurysm treated with an open left ilio-renal bypass, followed by two thoracic stents and a fenestrated graft. Fenestrations were constructed with a cautery cutting holes in positions dictated by the preoperative CT. The fenestrations were reinforced with Nitinol rings and gold markers were applied to the fenestrations and to the main body of the stent for proper orientation.
The Cleveland Clinic - Ohio - Dr. Greenberg - June 12, 2008
The first case was that of a 65 year-old male who underwent placement of a fenestrated aortic endograft about 2 months prior, now noted to have a left renal stent occlusion. He attempted to recanalize it, unsuccessfully. His experience with stenting visceral branching is of about 500 vessels, with about 18 failures up to 2006. Among those 18 cases, his success rate for recanalization is about 40%. The second case was that of a female patient with an infrarenal aortic aneurysm, repaired with a Cook endograft. The last case was a fenestrated aortic case, in a 63 year-old gentleman who had a prior Ancure graft placed who developed a type I endoleak. This patient required a graft with two fenestrations for the renal arteries and one fenestration for the superior mesenteric artery.
During my experience as the 21st Wylie fellow, I observed a myriad of endovascular and open cases worldwide. Moreover, I met at least 10 recognized leaders in the vascular surgery and radiology arena, and maybe another 50 people, among visiting surgeons from all over the world, nurses, radiology technologists and friends made along the way. This report was written with both immense pride and enormous gratitude to the American Vascular Association for the opportunity that I was given. It has been a true privilege in the light of the prestigious list of prior recipients and of the inspiration that Dr. Wylie’s work on arterial disease and that this experience will provide to my career. I realize the uniqueness of opportunities like this and it is with that in mind that I did my very best to obtain the maximum benefit out of this experience.
Posted June 2010