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Open versus endovascular repair of popliteal artery aneurysms
DEBATE Thomas L. Forbes, MD, Section Editor
Open versus endovascular repair of popliteal artery aneurysms Randy D. Moore, MD,a and Andrew B. Hill, MD,b Calgary, Alberta and Ottawa, Ontario, Canada A 72-year-old male presents with a large asymptomatic aneurysm of his left popliteal artery. He has a history of noninsulin dependent diabetes, hyptertension, and a prior history of a percutaneous intervention for a coronary artery stenosis. He is anatomically and physiologically a candidate for surgical or endovascular repair of his aneurysm. The following debate attempts to resolve whether open repair remains the gold standard for the treatment of popliteal artery aneurysms. ( J Vasc Surg 2010;51:271-6.)
Popliteal artery aneurysms (PAAs) account for approximately 70% of all peripheral aneurysms. The actual incidence is estimated to be less than 0.1%; consequently, no single center would expect to generate a large volume of clinical experience in any given year.1,2 The elective repair of asymptomatic PAAs is generally undertaken to prevent the clinical sequelae of arterial embolization, thrombosis, or, less commonly, rupture with subsequent risk to limb and life. The indications for repair are not well defined. However, diameter greater than 2 cm to 3 cm, particularly in those aneurysms with a heavy thrombus load or with chronic distal tibial artery embolic occlusion is generally considered an acceptable indication for repair.3-7 The surgical management of PAAs has been in evolution for centuries and was described as early as the third century AD in Greece. The Antyllus technique consisted of tourniquet control of the circulation, proximal and distal ligation of the popliteal aneurysm, evacuation of thrombus from within the aneurysm, and ligation of side branches of the popliteal aneurysm. Despite many modifications of technique over the centuries, surgical intervention was initially associated with a significant risk to limb and life. The morbidity and mortality associated with open repair led many in the 18th and 19th century to attempt other forms of therapy. Such therapies consisted of external comFrom the Division of Vascular Surgery, Peter Lougheed Centre and University of Calgarya and the Division of Vascular Surgery, The Ottawa Hospital and University of Ottawa.b Competition of interest: none. Reprint requests: Dr. Randy D. Moore, University of Calgary, Vascular Surgery, 3500 26th Ave. NE, Calgary, Alberta, Canada T1Y6J4 (e-mail: [email protected]) The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a competition of interest. 0741-5214/$36.00 Copyright © 2010 by the Society for Vascular Surgery. doi:10.1016/j.jvs.2009.09.060
pression and other modalities intended to cause thrombosis of the aneurysm. In the early part of the 20th century, Rudolph Matas described obliterative endoaneurysmoraphy and, 20 years ago, Edwards described PAA exclusion and revascularization with a vein bypass graft.4,7,8 More recently, experience with endovascular surgery expanded following Parodi’s description of the use of an endovascular stent graft for the repair of abdominal aortic aneurysms.9,10 The widespread adoption of endovascular aneurysm repair was only later followed and generally supported by randomized controlled trials.11-13 This changing treatment paradigm coincided with increasingly prevalent endovascular approaches for peripheral arterial occlusive disease. Percutaneous therapy is now often considered as the first treatment option and may be the preferred option for patients who might not otherwise be considered for surgery for occlusive disease, given the associated surgical morbidity and risk.14-18 The increasing prevalent role of endovascular therapies for peripheral arterial disease and the relative success of endovascular therapies for aortic aneurysmal disease have led to endovascular applications for the management of patients with PAAs (Figs 1 and 2). OPEN REPAIR REMAINS THE GOLD STANDARD (DR. RANDY MOORE) Prior to the incorporation of endovascular techniques into the modern vascular surgeon’s armamentarium, the notion of early technical success as a valid measure for outcome did not exist. Surgical techniques and surgical outcomes for the major vascular procedures used to treat vascular surgical pathology were compared with benchmark long-term results in order to determine efficacy and safety. Reliability was the key feature of a successful operative strategy. Webster’s dictionary defines reliable as: 1: suitable or fit to be relied on: dependable 2: giving the same result on successive trials 271
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Fig 1. Axial images of large left popliteal artery aneurysm.
Fig 2. Three-dimensional image of a left popliteal artery aneurysm.
The modern endovascular era has seen a paradigm shift in terms of successful vascular surgical care. As the volume of minimally interventional work has increased, so has our willingness to accept less reliable procedures with shorterterm success. Studies with 1 year follow-up results are now touted as intermediate or midterm outcomes. This is perhaps best exemplified by the current interest in the use of endovascular techniques for the treatment of PAAs. At the 28th Charing Cross Vascular Symposium held in London, England in the Spring of 2006, a poll of the attendees was undertaken after a debate session focused on
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PAA repair in order to assess the potential impact of endovascular techniques on PAA treatment. The overwhelming majority (79%) of the primarily surgical audience felt that endovascular techniques would not offer a reliable outcome for the treatment of this pathology. What was their reasoning? Simply put, open repair offers the patient with PAA a more reliable, more durable method for the treatment of their disease.19 There is an extensive body of literature that supports this. A retrospective analysis of data from 123 United States Veterans Affairs Medical Centers including 583 open operations for PAA in 537 patients from 1994 to 2005 was completed as part of the National Surgical Quality Improvement Program.20 This represents the largest reported North American series for PAA. Despite the fact that 88% of these patients were ASA Class 3 or 4, the 30-day mortality rate was only 1.4%, with a low 6.3% arterial-specific complication rate requiring reintervention. Unadjusted patient survival was 92.6% at 1 year and 86.1% at 2 years. The limb salvage rate for these surviving patients was 99% at 30 days, 97.6% at 1 year, and 96.2% at 2 years. Dependent preoperative functional status did worsen the 2 year limb salvage rate; however, at 2 years, 88.2% of these patients still had an intact limb. Likewise, an August 2007 report of data from the Swedish Vascular Registry documented the outcomes of 571 patients (717 limbs) operated for PAA and followed for a mean of 7.2 years.21 In 26 legs or 3.6% of this cohort, PAA was treated with endovascular techniques. The authors state that these small numbers precluded scientific analysis, however one-quarter of the legs treated with endovascular techniques were either converted to a bypass or were amputated at ⱕ 1 year. In contrast, limb salvage for the open surgical cohort was 81% at follow-up. One-third of patients with the medial approach technique developed further aneurysm expansion. This high expansion rate postligation is a critical observation that will further limit the long-term success of endovascular techniques, since the feeding branch vessels within the sac cannot be easily addressed during endograft repair. The posterior open approach in the Swedish study offered a lower re-expansion rate of 8.3%. Other authors have also observed a benefit for the posterior approach in terms of outcome. A series of 30 aneurysms in 24 patients treated with the posterior approach to PAA over 22 years were reported with a median follow-up of 22 months.22 Primary patency, primary assisted patency, and secondary patency rates were 92.2%, 95.8%, and 95.8% at follow-up, respectively, with a limb salvage rate of 100%. Another 358 PAAs in 289 patients, 21% of who had acute ischemia, were reported by Mayo Clinic investigators with a mean follow-up of 4.2 years.23 Remarkably, 32% of these patients underwent prosthetic repair. Peri-operative mortality was observed only in the acute ischemia group (1%), as was early amputation (8%). Five-year overall primary and secondary patency rates were 76% and 87% , and were much higher in the venous conduit cohort (85% and 94%) vs the prosthetic cohort (50 and 63%). The 5-year
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limb salvage rate was 97%, (85% in the acute ischemia group). Preoperative thrombolysis reduced the risk of amputation in acutely ischemic Class II patients (96% vs 69%). Seven recurrent PAAs required reintervention due to expansion or rupture. The authors concluded that a venous conduit with endoaneurysmoraphy to eliminate the risk of re-expansion remains the gold standard for PAA repair. Their observations were further supported by a longterm review of 48 patients having surgical repair of 63 PAAs and followed for over 10 years.24 A total of 45 PAAs were treated with ligation and bypass, while 18 underwent repair with interposition grafting. Although 25% of PAAs treated required late re-interventions, the 5-year primary graft patency, secondary graft patency, limb salvage, and patient survival rates were 75%, 95%, 98%, and 81%, respectively. At 10 years, 66% of these grafts remained primarily patent. This compares with the 56% 14-month overall patency rates reported in one of the earliest series of endovascular repair for PAA.25 In this early series, 11 patients had a total of 12 PAAs treated with covered stents. At 1 and 12 months, these investigators observed 47% primary patency and 75% secondary patency rates. Subsequent improvements in stent design did not appear to improve the outcomes for these patients. A series of 23 PAAs treated with the Hemobahn endovascular device demonstrated a 22% early occlusion rate, with a 74% primary patency at 1 year.26 Even experienced endovascular centers struggle with this new technology, with mechanical failure of the devices likely due to the extreme motion stresses placed upon these endografts across the point of maximal flexion during activity.27 Dr Eric Verhoeven and his center in Groeningen described 57 PAAs treated with the Hemobahn device, including 5 PAAs with acute occlusion and ischemia.28 During a mean follow-up of 24 months, 21% of these devices occluded, with primary and secondary patency rates of 80% and 90% at 1 year and 77% and 87% at 2 years. A follow-up report in Vascular News for the 2007 Charing Cross meeting described an overall 5-year primary patency rate of 70%, and a secondary patency of 79%. The results were improved with the addition of routine clopidogrel treatment after PAA endovascular repair, but do not compare with the results of larger series of open repair with longer-term follow-up. Another 56 PAA repairs with a mean follow-up of 16.5 months were reported in 2006, including 15 patients with endovascular PAA repair.29 Although the authors concluded that the retrospective review of these two cohorts demonstrated similar outcomes with respect to primary and secondary patency and survival rates, the groups were profoundly different in terms of patient selection. The majority of patients with open repair in this series were disadvantaged in that their intervention was for symptoms (54% vs 13%, P ⬍ .05) or acute ischemia (12% vs 0%, P ⬎ .05). In addition, over 25% of the open surgical cohort had prosthetic graft placement, even though one-third of patients had single-vessel run-off. The authors are to be commended on their excellent technical success with open
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repair under these circumstances! In addition, 20% of the endovascular cohort had endoleaks, putting their repair at risk for long-term failure due to further sac enlargement or rupture. The only prospective study comparing open and endovascular repair for the treatment of PAA reported similar outcomes at a mean follow-up of 46 months for the two modalities of treatment, with shorter operative times and length of stay for the endovascular group.30 However, the study was flawed by the authors’ self-confessed lack of power (only 15 patients in each treatment arm), and by the use of an inferior conduit: below-knee prosthetic graft in 27.6% of the open-repair treatment group. Despite this significant bias against open repair, 100% primary patency was observed for the open group vs. 86.7% for the endovascular group at 12 months. Furthermore, during the same time period, the authors completed another 18 open surgical PAA repairs outside of the study inclusion criteria for patients with acute ischemia or poor runoff. The study therefore only reports on the selected 65% of the PAA patients that were randomized at the institution. Finally, a meta-analysis of published studies comparing endovascular and open surgical outcomes for PAA treatment documented no significant differences in long-term primary patency rates between the two types of repair, but observed an 18-fold increased risk for re-intervention (odds ratio [OR], 18.80; P ⫽ .03), and a five-fold increased risk for 30-day graft thrombosis (OR, 5.05; P ⫽ .06) in the endovascular group. The authors conclude that with current technology, it is difficult to justify endovascular treatment for PAA.31 In summary, endovascular repair intuitively may seem to be an ideal approach for patients with PAA in order to minimize the impact of open surgical morbidity. However, the abundance of small endovascular series from single centers, and the lack of large and/or long-term series to support this notion, coupled with the reported inferior patency rates compared with large and long-term series for open repair, and the difficulty in addressing the significant PAA endoleak and re-expansion rates after exclusion, currently renders the endovascular technique less than ideal for all but the most physiologically intolerant of patients. In short, endovascular repair for PAA is not reliable enough to be considered the standard for repair. Further improvements in prosthetic bypass technology including heparinbonded ePTFE grafts32 will only serve to improve open reconstruction options and results for open PAA repair. Open surgical repair remains the gold standard. OPEN REPAIR IS NO LONGER THE GOLD STANDARD: THE CASE FOR ENDOVASCULAR REPAIR (DR. ANDREW HILL) Surgical interventions, like most forms of therapy in medicine, are in constant evolution. This evolution is the result of continuous treatment evaluation and technical improvements to optimize patient outcome. With time, old maxims and accepted standards of care tend to fall by the wayside as superior treatment methods are introduced.
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Procedures such as trepanation and blood-letting, historically prescribed for multiple ailments, have been relegated to the annals of history as more disease-specific therapies have evolved. In more modern times, minimally invasive general surgery has rapidly replaced traditional open surgical techniques. The introduction of technology such as laparoscopic cholecystectomy, spurred on by public demand, has often outpaced the ability to critically evaluate the new procedures with prospective randomized controlled trials. For the most part, however, the potential benefits of such minimally invasive procedures have been confirmed with time. These benefits include reduction in patient discomfort, postoperative complications and disability, hospital length of stay, tissue injury, postoperative inflammatory response, and postoperative immunosuppression.33,34 Although laparoscopic techniques were only introduced to general surgeons in 1987, the subsequent 20 years has seen a rapid dissemination of minimally invasive laparoscopic techniques to all areas of general surgery for most practicing general surgeons. It is important to recognize that the average asymptomatic patient being considered for elective popliteal artery intervention tends to be an older male (96%) with multiple co-morbidities. This should influence treatment options due to operative risk and overall reduced life expectancy. Almost half of such patients will have bilateral PAAs and a significant proportion of patients can have synchronous aneurysms with the potential requirement for multiple interventions.2,21 Traditional open surgical repair often requires multiple and/or long leg incisions with the subsequent risk of wound complications, leg edema, prolonged hospital stay, slow return to normal function, and associated risk of systemic complications. These factors would tend to favor the development of a minimally invasive option for repair of a PAA. When staging an argument for endovascular aneurysm repair, one should consider whether or not a true and tested gold standard currently exists for open surgical repair, the relative morbidity of open surgery, and the long-term patency and limb salvage rates for open and endovascular aneurysm repair. The introduction of new technology often requires evaluation against the accepted standard of care or the traditional standard of therapy. It can be argued, however, that a single well-defined open surgical procedure does not exist for comparison with endovascular aneurysm repair. Much has changed in the world during the 40 years that followed Edwards’ publication8; however, the optimal open surgical approach for repair of a PAA has not been standardized. Options have included simple bypass of the aneurysm, aneurysm exclusion and vein bypass, and bypass by lateral or posterior approach. Additionally, there are differences of opinion regarding the benefit of ligating the geniculate branches of the PAA.2,21,24,35-37 When one considers the various available open surgical approaches, a quick survey of PubMed demonstrates the complete lack of prospective randomized controlled studies documenting a particular benefit for one method of open surgical repair
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over another. The elective surgical management available for patients with a PAA is varied, has been changing with time, and has not been subjected to randomized comparison when considering one open surgical recommendation over another. A reasonable question persists as to whether or not a true open surgical gold standard operation exists for the management of patients with PAAs. When offering patients elective therapy for an asymptomatic PAA, one must keep in mind the patient’s age, co-morbidities, life expectancy, the potential presence of synchronous aneurysms, and the possible requirement for multiple interventions. Such surgery is prophylactic; consequently, surgical risk should be minimal. Open surgical repair of a PAA generally requires multiple incisions in the leg, dissection and disruption of the anatomy of the popliteal fossa, groin incisions, and a risk for wound and systemic complications. In one nationwide study of patients treated surgically for popliteal artery aneurysm, a 2% limb loss per year was documented following open surgical repair. There were significant rates of perioperative complications such as neurologic, infection, seroma, and hematoma.21 Open surgical repair of PAAs is associated with at least a 1.6% operative mortality rate.24 Despite open repair, there can be a 30% risk of aneurysmal expansion over time, even without obvious flow from geniculate branches. There is even potential for rupture of a previously bypassed PAA.35,38 Compartment syndrome has been reported as a long-term complication following bypass of a PAA.39 Postoperative leg swelling has been documented in over 50% of patients following bypass surgery.40 Various reports of bypass surgery in the leg have documented up to a 10% to 20% risk of surgical site infection.41 An endovascular approach to repair of a PAA is attractive because of the potential to minimize patient morbidity, duration of hospitalization, and recovery time. These are all important issues, particularly in a frail patient population that may require multiple interventions. However, the patency of endovascular stent grafts in the popliteal artery should not be inferior to that obtained with open bypass surgery. The feasibility of an endovascular approach to the management of patients with a PAA was demonstrated in early case reports and small clinical series.42-51 Although a variety of devices were described, most reported good early technical success without significant morbidity, no mortality, and short hospital stays. Concern was expressed, however, about the undocumented long-term patency of this new approach. The surgical data available on long-term outcome for open repair of PAAs is not large, given the relatively low incidence of the problem and the difficulty for any one center to accumulate a large experience. However, data does exist. Two relatively large contemporary case series of open surgical repair for 356 PAAs have documented 5-year primary patency rates of 75% to 85% for autogenous vein grafts.23,24 These rates compare favorably with a systematic review of literature that included 2,445 PAA repairs that
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demonstrated a range of 77% to 100% 5-year primary patency rate for vein grafts.1 Case series of endovascular PAA repair have suggested that these minimally invasive grafts may not have inferior patency results when compared with the historical controls for open surgical repair. A recent study of 23 endovascular procedures for PAAs demonstrated a 93% primary and 100% secondary 1-year patency rate.52 Another relatively large study of 35 PAAs demonstrated 75% 3-year primary patency and 83.2% secondary patency.53 In a larger study of 73 PAAs treated with endovascular therapy, Tielliu demonstrated 70% 5-year primary and 76% secondary patency rates.54 The 5-year primary patency rates improved over time to 80% with clinical experience and the addition of clopidogrel to postoperative patient management. A retrospective cohort study of open (n ⫽ 41) and endovascular (n ⫽ 15) PAA repair has demonstrated similar 1 to 2 year patency rates.29 These early data suggest at least noninferiority for patency rates for endovascular stent graft repair of PAAs compared with various traditional open surgical repairs. A prospective comparative study of open (n ⫽ 27) and endovascular (n ⫽ 21) repair demonstrated no primary or secondary patency differences out to 72 months of followup.55 This study included data from a randomized controlled study of open and endovascular popliteal aneurysm repair that did not demonstrate a patency difference between the two approaches out to 3 years of follow-up.30 Lovegrove has published a meta-analysis of all comparative studies of open (n ⫽ 104) and endovascular (n ⫽ 37) popliteal aneurysm repair. This study demonstrated similar patency rates between the two techniques, although the reintervention rate for endovascular grafts was higher than that required for open surgery. In summary, endovascular repair of PAAs has replaced open repair as the gold standard, as it has comparable patency without the associated local and systemic complications associated with open surgery. AUTHOR CONTRIBUTIONS Conception and design: AH, RM Analysis and interpretation: AH, RM Data collection: AH, RM Writing the article: AH, RM Critical revision of the article: AH, RM Final approval of the article: AH, RM Statistical analysis: AH, RM Obtained funding: N/A Overall responsibility: AH, RM REFERENCES 1. Dawson I, Sie RB, van Bockel H. Atherosclerotic popliteal aneurysm. Br J Surg 1997;84:293-9. 2. Henke PK. Popliteal artery aneurysms: tried, true, and new approaches to therapy. Semin Vasc Surg 2005;18:224-30. 3. Mousa AY, Beauford RB, Henderson P, Patel P, Faries PL, Flores L, Fogler R. Update on the diagnosis and management of popliteal aneurysm and literature review. Vascular 2006;4:103-8.
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4. Galland RB. Popliteal aneurysms: from John Hunter to the 21st century. Ann R Coll Surg Engl 2007;89:466-71. 5. Loukas M, Klaasen Z, Tubbs RS, Apaydin N. Popliteal artery aneurysms: a review. Folia Morphol (Warsz) 2007;66:272-6. 6. Wain RA, Hines G. A contemporary review of popliteal artery aneurysms. Cardiol Rev 2007;15:102-7. 7. Galland RB. History of the management of popliteal artery aneurysms. Eur J Vasc Endovasc Surg 2008;35:466-72. 8. Edwards WS. Exclusion and saphenous vein bypass of popliteal artery aneurysms. Surg Gynecol Obstet 1969;128:829-30. 9. Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg 1991;5: 491-9. 10. Parodi JC, Criado FJ, Barone HD, Schonholz C, Queral LA. Endoluminal aortic aneurysm repair using a balloon-expandable stent-graft device: a progress report. Ann Vasc Surg 1994;8:523-9. 11. Greenhalgh RM, Brown LC, Kwong GP, Powell JT, Thompson SG. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial. Lancet 2004;364:843-8. 12. Prinssen M, Verhoeven EL, Buth J, Cuybers PW, van Sambeek MR, Balm R, et al. A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med 2004;351: 1607-18. 13. Blankensteijn JD, de Jong SE, Prinssen M, van der Ham AC, Buth J, van Sterkenburg SM, et al. Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms. N Engl J Med 2005;352:2398-405. 14. Adam DJ, Beard JD, Cleveland T, Bell J, Bradbury Aw, Forbes JF, et al. Bypass versus angioplasty in severe ischaemia of the leg (BASIL): multicenter, randomised controlled trial. Lancet 2005;366:1925-34. 15. Almahameed A, Bhatt DL. Contemporary management of peripheral arterial disease: III. Endovascular and surgical management. Cleve Clin J Med 2006;73(Suppl 4):S45-51. 16. Singh KP, Patel MR, Kandzari DE, Zidar JP. Peripheral arterial disease: an overview of endovascular therapies and contemporary treatment strategies. Rev Cardiovasc Med 2006;7:55-68. 17. Mardikar HM, Mukherjee D. Current endovascular treatment of peripheral arterial disease. Prog Cardiovasc Nurs 2007;22:31-7. 18. White CJ, Gray WA. Endovascular therapies for peripheral arterial disease: an evidence-based review. Circulation 2007;116:2203-15. 19. Charing Cross Symposium News: online link. Available at: http:// cxnx.affinoworld.com/cxsymp/cxsymp.cfm?ccs⫽306. Accessed . 20. Johnson ON, Slidell MB, Macsata RA, Faler BJ, Amdur RL, Sidawy AN. Outcomes of surgical management for popliteal artery aneurysms: An analysis of 583 cases. J Vasc Surg 2008;48:845-51. 21. Ravn H, Wanhainen A, Bjorck M, Swedish Vascular Registry. Surgical technique and long-term results after popliteal artery aneurysm repair: results from 717 legs. J Vasc Surg 2007;46:236-43. 22. Beseth B, Moore WS. The posterior approach for repair of popliteal aneurysms. J Vasc Surg 2006;43:940-5. 23. Huang Y, Gloviczki P, Noel A, Sullivan T, Kalra M, Gullerud RE, et al. Early complications and long-term outcome after open surgical treatment of popliteal artery aneurysms: is exclusion with saphenous vein bypass still the gold standard? J Vasc Surg 2007;45:706-13. 24. Davies RS, Wall M, Rai S, Simms MH, Vohra RK, Bradbury AW, Adam DJ. Long-term results of surgical repair of popliteal artery aneurysm. Eur J Vasc Endovasc Surg 2007;34:714-18. 25. Gerasimidis T, Sfyroeras G, Papazoglou K, Trellopoulos G, Ntinas A, Karamanos D. Endovascular treatment of popliteal artery aneurysms. Eur J Vasc Endovasc Surg 2003;26:506-11. 26. Tielliu IF, Verhoeven EL, Prins TR, Post WJ, Hulsebos RG, van den Dungen JJ. Treatment of popliteal artery aneurysms with the Hemobahn stent-graft. J Endovasc Ther 2003;10:111-6. 27. Ranson M, Adelman MA, Cayne NS, Maldonado TS, Muhs B. Total Viabahn endoprosthesis collapse. J Vasc Surg 2008;47:454-6. 28. Tielliu IFJ, Verhoeven EL, Zeebregts CJ, Prins TR, Span MM, van den Dungen JJ. Endovascular treatment of popliteal artery aneurysms: results of a prospective cohort study. J Vasc Surg 2005;41:561-7.
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29. Curi MA, Geraghty PJ, Merino OA, Verraswamy RK, Rubin BG, Sanchez LA, et al. Mid-term outcomes of endovascular popliteal artery aneurysm repair. J Vasc Surg 2007;45:505-10. 30. Antonello M, Frigatti P, Battocchio P, Lepidi S, Cognolato D, Dall’Antonia A, et al. Open repair versus endovascular treatment for asymptomatic popliteal artery aneurysm: results of a prospective randomized study. J Vasc Surg 2005;42:185-93. 31. Lovegrove RE, Javid M, Magee TR, Galland RB. Endovascular and open approaches to non-thrombosed popliteal aneurysm repair: a meta analysis. Eur J Vasc Endovasc Surg 2008;36:96-100. 32. Daenens K, Schepers S, Fourneau I, Houthoofd S, Nevelsteen A. Heparin bonded ePTFE grafts compared with vein grafts in femoralpopliteal and femoralcrural bypasses: 1- and 2-year results. J Vasc Surg 2009;49:1210-6. 33. Satava R. Innovative technologies. The information age and the biointelligence age. Surg Endosc 2000;14:417-8. 34. Khaitan L, Holtzman MD. Laparoscopic advances in general surgery. JAMA 2002;287:1502-5. 35. Ebaugh JL, Morasch MD, Matsumura JS, Eskandari MK, Meadows WS, Pearce WH. Fate of excluded popliteal artery aneurysms. J Vasc Surg 2003;37:954-9. 36. Mehta M, Champagne B, Darling RC, Roddy SP, Kreienberg PB, Ozsvath KJ, et al. Outcome of popliteal artery aneurysms after exclusion and bypass: significance of residual patent branches mimicking type II endoleaks. J Vasc Surg 2004;40:886-90. 37. Kropman RH, DeVries JP, Moll FL. Surgical and endovascular treatment of atherosclerotic popliteal artery aneurysms. J Cardiovasc Surg 2007;48:281-8. 38. Battey PM, Skardasis GM, McKinnon WM. Rupture of a previously bypassed popliteal aneurysm: a case report. J Vasc Surg 1987;5:874-5. 39. Batt M, Sosa M, Bouillannne PJ, Thevenin B, Haudebourg P, HassenKhodja R. Acute compartment syndrome: an unusual complication of a previously bypassed popliteal aneurysm-case report and literature review. J Vasc Surg 2006;43:1049-52. 40. Soong CV, Barros B’Sa AA. Lower limb oedema following distal arterial bypass grafting. Eur J Vasc Endovasc Surg 1998;16:465-71. 41. Bandyk DF. Vascular surgical site infection: risk factors and preventive measures. Semin Vasc Surg 2008;21:119-23. 42. Marin ML, Veith FJ, Panetta TF, Cynamon J, Bakal CW, Suggs WD, et al. Transfemoral endoluminal stented graft repair of a popliteal artery aneurysm. J Vasc Surg 1994;19:754-7. 43. Joyce WP, McGrath F, Leahy AL, Bouchier-Hayes D. A safe combined surgical/radiological approach to endoluminal graft stenting of a popliteal artery aneurysm. Eur J Vasc Endovasc Surg 1995;10;489-91.
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44. Henry M, Amor M, Craff A, Porte PM, Henry I, Amicabile C, Tricoche O. Occlusive and aneurismal peripheral arterial disease: assessment of a stent-graft system. Radiology 1996;201:717-24. 45. Marcade JP. Stent graft for popliteal aneurysms. Six cases with Cragg Endo-Pro System 1 Mintec. J Cardiovasc Surg (Torino) 1996; 37(3 Suppl 1):41-4. 46. Rousseau H, Gieskes L, Joffre F, Dube M, Roux D, Soula P, et al. Percutaneous treatment of peripheral aneurysms with the Craff EndoPro System. J Vasc Interv Radiol 1996;7:35-9. 47. Krajcer Z, Diethrich EB. Successful endoluminal repair of arterial aneurysms by Wallstent prosthesis and PTFE graft: preliminary results with a new technique. J Endovasc Surg 1997;4:80-7. 48. Burger T, Meyer F, Tautenhahn J, Halloul Z, Fahlke J. Initial experiences with percutaneous endovascular repair of popliteal artery lesions using a new PTFE stent-graft. J Endovasc Surg 1998;5:365-72. 49. Kudelko PE, Alfaro-Franco C, Diethrich EB, Krajcer Z. Successful endoluminal repair of a popliteal artery aneurysm using the Wallgraft endoprosthesis. J Endovasc Surg 1998;5:373-7. 50. Puech-Leao P, Kauffman P, Wolosker N, Anacleto AM. Endovascular grafting of a popliteal aneurysm using the saphenous vein. J Endovasc Surg 1998;5:64-70. 51. Rosenthal D, Atkins CP, Schuler FW, Jerius HS, Clark MD, Matsuura JH. Popliteal artery aneurysm treated with a minimally invasive endovascular approach: an initial report. J Endovasc Surg 1998;5:60-3. 52. Rajasinghe HA, Tzilinis A, Keller T, Schafer J, Urrea S. Endovascular exclusion of popliteal artery aneurysm with expanded polytetrafluoroethylene stent-grafts: early results. Vasc Endovascular Surg 2006;40: 460-6. 53. Mohan IV, Bray PJ, Harris JP, May J, Stephen MS, Bray AE, White GH. Endovascular popliteal aneurysm repair: are the results comparable to open surgery? Eur J Vasc Endovasc Surg 2006;32:149-54. 54. Tielliu IF, Verhoeven EL, Zeebregts CJ, Prins TR, Bos WT, Van den Dungen JJ. Endovascular treatment of popliteal artery aneurysms: is the technique a valid alternative to open surgery? J Cardiovasc Surg (Torino) 2007;48:275-9. 55. Antonello M, Frigatti P, Battocchio P, Lepidi S, Dall’Antonia A, Deriu GP, Grego F. Endovascular treatment of asymptomatic popliteal aneurysms: 8-year concurrent comparison with open repair. J Cardiovasc Surg (Torino) 2007;48:267-74.
Submitted Sep 14, 2009; accepted Sep 15, 2009.
COMMENTARY
Thomas L. Forbes, MD, London, Ontario, Canada As endovascular stent grafts gained a firm foothold in the treatment of aortic aneurysms, we have seen the continued application of this therapy to aneurysmal disease in other vascular beds. The popliteal artery is no exception and offers unique challenges compared with the aorta. In the current debate, Drs Hill and Moore provide logical arguments for and against an endovascular approach to popliteal artery aneurysm (PAA) repair. There are several knowledge gaps regarding PAA management. First of all, little is known of the natural history of untreated aneurysms. As a result, any treatment recommendation based on aneurysm diameter is less robust than with aortic aneurysms. The indications for treatment differ as well, with PAAs rarely rupturing and more commonly causing thrombosis, embolization, or compressive symptoms. Most of these complications can be potentially prevented by open or endovascular repair. However, differing from the aorta, little has been described regarding PAA regression following endovascular repair. As a result, compressive symptoms caused by popliteal aneurysms are best treated with an open repair that includes sac decompression.
A consistent argument against new endovascular therapies is the relative absence of long term data, as Dr Moore clearly states. In this climate, it’s a wonder that any new endovascular technology takes hold as we continue to subject it to more intense surveillance than the open surgical “gold standard” and initially select higherrisk individuals to treat. Additionally, these evaluations occur when the technology is still maturing and, as Dr Hill states, the “gold standard” for open PAA repair is ill-defined and comprises several operations that could easily be the topic of another debate. For these reasons, the approximately similar patency and limb salvage rates with endovascular and open PAA repair is encouraging and generally offers support for an endovascular approach, rather than discouraging. A clear advantage of an endovascular approach is the reduction in the morbidity more often associated with open repair, namely local wound healing and infection-related complications. There is not much debate around this issue nor the reality that endovascular therapy of popliteal aneurysms is here to stay and is attractive to many of our patients.
Open versus endovascular repair of popliteal artery aneurysms Randy D. Moore, MD,a and Andrew B. Hill, MD,b Calgary, Alberta and Ottawa, Ontario, Canada A 72-year-old male presents with a large asymptomatic aneurysm of his left popliteal artery. He has a history of noninsulin dependent diabetes, hyptertension, and a prior history of a percutaneous intervention for a coronary artery stenosis. He is anatomically and physiologically a candidate for surgical or endovascular repair of his aneurysm. The following debate attempts to resolve whether open repair remains the gold standard for the treatment of popliteal artery aneurysms. ( J Vasc Surg 2010;51:271-6.)
Popliteal artery aneurysms (PAAs) account for approximately 70% of all peripheral aneurysms. The actual incidence is estimated to be less than 0.1%; consequently, no single center would expect to generate a large volume of clinical experience in any given year.1,2 The elective repair of asymptomatic PAAs is generally undertaken to prevent the clinical sequelae of arterial embolization, thrombosis, or, less commonly, rupture with subsequent risk to limb and life. The indications for repair are not well defined. However, diameter greater than 2 cm to 3 cm, particularly in those aneurysms with a heavy thrombus load or with chronic distal tibial artery embolic occlusion is generally considered an acceptable indication for repair.3-7 The surgical management of PAAs has been in evolution for centuries and was described as early as the third century AD in Greece. The Antyllus technique consisted of tourniquet control of the circulation, proximal and distal ligation of the popliteal aneurysm, evacuation of thrombus from within the aneurysm, and ligation of side branches of the popliteal aneurysm. Despite many modifications of technique over the centuries, surgical intervention was initially associated with a significant risk to limb and life. The morbidity and mortality associated with open repair led many in the 18th and 19th century to attempt other forms of therapy. Such therapies consisted of external comFrom the Division of Vascular Surgery, Peter Lougheed Centre and University of Calgarya and the Division of Vascular Surgery, The Ottawa Hospital and University of Ottawa.b Competition of interest: none. Reprint requests: Dr. Randy D. Moore, University of Calgary, Vascular Surgery, 3500 26th Ave. NE, Calgary, Alberta, Canada T1Y6J4 (e-mail: [email protected]) The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a competition of interest. 0741-5214/$36.00 Copyright © 2010 by the Society for Vascular Surgery. doi:10.1016/j.jvs.2009.09.060
pression and other modalities intended to cause thrombosis of the aneurysm. In the early part of the 20th century, Rudolph Matas described obliterative endoaneurysmoraphy and, 20 years ago, Edwards described PAA exclusion and revascularization with a vein bypass graft.4,7,8 More recently, experience with endovascular surgery expanded following Parodi’s description of the use of an endovascular stent graft for the repair of abdominal aortic aneurysms.9,10 The widespread adoption of endovascular aneurysm repair was only later followed and generally supported by randomized controlled trials.11-13 This changing treatment paradigm coincided with increasingly prevalent endovascular approaches for peripheral arterial occlusive disease. Percutaneous therapy is now often considered as the first treatment option and may be the preferred option for patients who might not otherwise be considered for surgery for occlusive disease, given the associated surgical morbidity and risk.14-18 The increasing prevalent role of endovascular therapies for peripheral arterial disease and the relative success of endovascular therapies for aortic aneurysmal disease have led to endovascular applications for the management of patients with PAAs (Figs 1 and 2). OPEN REPAIR REMAINS THE GOLD STANDARD (DR. RANDY MOORE) Prior to the incorporation of endovascular techniques into the modern vascular surgeon’s armamentarium, the notion of early technical success as a valid measure for outcome did not exist. Surgical techniques and surgical outcomes for the major vascular procedures used to treat vascular surgical pathology were compared with benchmark long-term results in order to determine efficacy and safety. Reliability was the key feature of a successful operative strategy. Webster’s dictionary defines reliable as: 1: suitable or fit to be relied on: dependable 2: giving the same result on successive trials 271
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Fig 1. Axial images of large left popliteal artery aneurysm.
Fig 2. Three-dimensional image of a left popliteal artery aneurysm.
The modern endovascular era has seen a paradigm shift in terms of successful vascular surgical care. As the volume of minimally interventional work has increased, so has our willingness to accept less reliable procedures with shorterterm success. Studies with 1 year follow-up results are now touted as intermediate or midterm outcomes. This is perhaps best exemplified by the current interest in the use of endovascular techniques for the treatment of PAAs. At the 28th Charing Cross Vascular Symposium held in London, England in the Spring of 2006, a poll of the attendees was undertaken after a debate session focused on
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PAA repair in order to assess the potential impact of endovascular techniques on PAA treatment. The overwhelming majority (79%) of the primarily surgical audience felt that endovascular techniques would not offer a reliable outcome for the treatment of this pathology. What was their reasoning? Simply put, open repair offers the patient with PAA a more reliable, more durable method for the treatment of their disease.19 There is an extensive body of literature that supports this. A retrospective analysis of data from 123 United States Veterans Affairs Medical Centers including 583 open operations for PAA in 537 patients from 1994 to 2005 was completed as part of the National Surgical Quality Improvement Program.20 This represents the largest reported North American series for PAA. Despite the fact that 88% of these patients were ASA Class 3 or 4, the 30-day mortality rate was only 1.4%, with a low 6.3% arterial-specific complication rate requiring reintervention. Unadjusted patient survival was 92.6% at 1 year and 86.1% at 2 years. The limb salvage rate for these surviving patients was 99% at 30 days, 97.6% at 1 year, and 96.2% at 2 years. Dependent preoperative functional status did worsen the 2 year limb salvage rate; however, at 2 years, 88.2% of these patients still had an intact limb. Likewise, an August 2007 report of data from the Swedish Vascular Registry documented the outcomes of 571 patients (717 limbs) operated for PAA and followed for a mean of 7.2 years.21 In 26 legs or 3.6% of this cohort, PAA was treated with endovascular techniques. The authors state that these small numbers precluded scientific analysis, however one-quarter of the legs treated with endovascular techniques were either converted to a bypass or were amputated at ⱕ 1 year. In contrast, limb salvage for the open surgical cohort was 81% at follow-up. One-third of patients with the medial approach technique developed further aneurysm expansion. This high expansion rate postligation is a critical observation that will further limit the long-term success of endovascular techniques, since the feeding branch vessels within the sac cannot be easily addressed during endograft repair. The posterior open approach in the Swedish study offered a lower re-expansion rate of 8.3%. Other authors have also observed a benefit for the posterior approach in terms of outcome. A series of 30 aneurysms in 24 patients treated with the posterior approach to PAA over 22 years were reported with a median follow-up of 22 months.22 Primary patency, primary assisted patency, and secondary patency rates were 92.2%, 95.8%, and 95.8% at follow-up, respectively, with a limb salvage rate of 100%. Another 358 PAAs in 289 patients, 21% of who had acute ischemia, were reported by Mayo Clinic investigators with a mean follow-up of 4.2 years.23 Remarkably, 32% of these patients underwent prosthetic repair. Peri-operative mortality was observed only in the acute ischemia group (1%), as was early amputation (8%). Five-year overall primary and secondary patency rates were 76% and 87% , and were much higher in the venous conduit cohort (85% and 94%) vs the prosthetic cohort (50 and 63%). The 5-year
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limb salvage rate was 97%, (85% in the acute ischemia group). Preoperative thrombolysis reduced the risk of amputation in acutely ischemic Class II patients (96% vs 69%). Seven recurrent PAAs required reintervention due to expansion or rupture. The authors concluded that a venous conduit with endoaneurysmoraphy to eliminate the risk of re-expansion remains the gold standard for PAA repair. Their observations were further supported by a longterm review of 48 patients having surgical repair of 63 PAAs and followed for over 10 years.24 A total of 45 PAAs were treated with ligation and bypass, while 18 underwent repair with interposition grafting. Although 25% of PAAs treated required late re-interventions, the 5-year primary graft patency, secondary graft patency, limb salvage, and patient survival rates were 75%, 95%, 98%, and 81%, respectively. At 10 years, 66% of these grafts remained primarily patent. This compares with the 56% 14-month overall patency rates reported in one of the earliest series of endovascular repair for PAA.25 In this early series, 11 patients had a total of 12 PAAs treated with covered stents. At 1 and 12 months, these investigators observed 47% primary patency and 75% secondary patency rates. Subsequent improvements in stent design did not appear to improve the outcomes for these patients. A series of 23 PAAs treated with the Hemobahn endovascular device demonstrated a 22% early occlusion rate, with a 74% primary patency at 1 year.26 Even experienced endovascular centers struggle with this new technology, with mechanical failure of the devices likely due to the extreme motion stresses placed upon these endografts across the point of maximal flexion during activity.27 Dr Eric Verhoeven and his center in Groeningen described 57 PAAs treated with the Hemobahn device, including 5 PAAs with acute occlusion and ischemia.28 During a mean follow-up of 24 months, 21% of these devices occluded, with primary and secondary patency rates of 80% and 90% at 1 year and 77% and 87% at 2 years. A follow-up report in Vascular News for the 2007 Charing Cross meeting described an overall 5-year primary patency rate of 70%, and a secondary patency of 79%. The results were improved with the addition of routine clopidogrel treatment after PAA endovascular repair, but do not compare with the results of larger series of open repair with longer-term follow-up. Another 56 PAA repairs with a mean follow-up of 16.5 months were reported in 2006, including 15 patients with endovascular PAA repair.29 Although the authors concluded that the retrospective review of these two cohorts demonstrated similar outcomes with respect to primary and secondary patency and survival rates, the groups were profoundly different in terms of patient selection. The majority of patients with open repair in this series were disadvantaged in that their intervention was for symptoms (54% vs 13%, P ⬍ .05) or acute ischemia (12% vs 0%, P ⬎ .05). In addition, over 25% of the open surgical cohort had prosthetic graft placement, even though one-third of patients had single-vessel run-off. The authors are to be commended on their excellent technical success with open
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repair under these circumstances! In addition, 20% of the endovascular cohort had endoleaks, putting their repair at risk for long-term failure due to further sac enlargement or rupture. The only prospective study comparing open and endovascular repair for the treatment of PAA reported similar outcomes at a mean follow-up of 46 months for the two modalities of treatment, with shorter operative times and length of stay for the endovascular group.30 However, the study was flawed by the authors’ self-confessed lack of power (only 15 patients in each treatment arm), and by the use of an inferior conduit: below-knee prosthetic graft in 27.6% of the open-repair treatment group. Despite this significant bias against open repair, 100% primary patency was observed for the open group vs. 86.7% for the endovascular group at 12 months. Furthermore, during the same time period, the authors completed another 18 open surgical PAA repairs outside of the study inclusion criteria for patients with acute ischemia or poor runoff. The study therefore only reports on the selected 65% of the PAA patients that were randomized at the institution. Finally, a meta-analysis of published studies comparing endovascular and open surgical outcomes for PAA treatment documented no significant differences in long-term primary patency rates between the two types of repair, but observed an 18-fold increased risk for re-intervention (odds ratio [OR], 18.80; P ⫽ .03), and a five-fold increased risk for 30-day graft thrombosis (OR, 5.05; P ⫽ .06) in the endovascular group. The authors conclude that with current technology, it is difficult to justify endovascular treatment for PAA.31 In summary, endovascular repair intuitively may seem to be an ideal approach for patients with PAA in order to minimize the impact of open surgical morbidity. However, the abundance of small endovascular series from single centers, and the lack of large and/or long-term series to support this notion, coupled with the reported inferior patency rates compared with large and long-term series for open repair, and the difficulty in addressing the significant PAA endoleak and re-expansion rates after exclusion, currently renders the endovascular technique less than ideal for all but the most physiologically intolerant of patients. In short, endovascular repair for PAA is not reliable enough to be considered the standard for repair. Further improvements in prosthetic bypass technology including heparinbonded ePTFE grafts32 will only serve to improve open reconstruction options and results for open PAA repair. Open surgical repair remains the gold standard. OPEN REPAIR IS NO LONGER THE GOLD STANDARD: THE CASE FOR ENDOVASCULAR REPAIR (DR. ANDREW HILL) Surgical interventions, like most forms of therapy in medicine, are in constant evolution. This evolution is the result of continuous treatment evaluation and technical improvements to optimize patient outcome. With time, old maxims and accepted standards of care tend to fall by the wayside as superior treatment methods are introduced.
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Procedures such as trepanation and blood-letting, historically prescribed for multiple ailments, have been relegated to the annals of history as more disease-specific therapies have evolved. In more modern times, minimally invasive general surgery has rapidly replaced traditional open surgical techniques. The introduction of technology such as laparoscopic cholecystectomy, spurred on by public demand, has often outpaced the ability to critically evaluate the new procedures with prospective randomized controlled trials. For the most part, however, the potential benefits of such minimally invasive procedures have been confirmed with time. These benefits include reduction in patient discomfort, postoperative complications and disability, hospital length of stay, tissue injury, postoperative inflammatory response, and postoperative immunosuppression.33,34 Although laparoscopic techniques were only introduced to general surgeons in 1987, the subsequent 20 years has seen a rapid dissemination of minimally invasive laparoscopic techniques to all areas of general surgery for most practicing general surgeons. It is important to recognize that the average asymptomatic patient being considered for elective popliteal artery intervention tends to be an older male (96%) with multiple co-morbidities. This should influence treatment options due to operative risk and overall reduced life expectancy. Almost half of such patients will have bilateral PAAs and a significant proportion of patients can have synchronous aneurysms with the potential requirement for multiple interventions.2,21 Traditional open surgical repair often requires multiple and/or long leg incisions with the subsequent risk of wound complications, leg edema, prolonged hospital stay, slow return to normal function, and associated risk of systemic complications. These factors would tend to favor the development of a minimally invasive option for repair of a PAA. When staging an argument for endovascular aneurysm repair, one should consider whether or not a true and tested gold standard currently exists for open surgical repair, the relative morbidity of open surgery, and the long-term patency and limb salvage rates for open and endovascular aneurysm repair. The introduction of new technology often requires evaluation against the accepted standard of care or the traditional standard of therapy. It can be argued, however, that a single well-defined open surgical procedure does not exist for comparison with endovascular aneurysm repair. Much has changed in the world during the 40 years that followed Edwards’ publication8; however, the optimal open surgical approach for repair of a PAA has not been standardized. Options have included simple bypass of the aneurysm, aneurysm exclusion and vein bypass, and bypass by lateral or posterior approach. Additionally, there are differences of opinion regarding the benefit of ligating the geniculate branches of the PAA.2,21,24,35-37 When one considers the various available open surgical approaches, a quick survey of PubMed demonstrates the complete lack of prospective randomized controlled studies documenting a particular benefit for one method of open surgical repair
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over another. The elective surgical management available for patients with a PAA is varied, has been changing with time, and has not been subjected to randomized comparison when considering one open surgical recommendation over another. A reasonable question persists as to whether or not a true open surgical gold standard operation exists for the management of patients with PAAs. When offering patients elective therapy for an asymptomatic PAA, one must keep in mind the patient’s age, co-morbidities, life expectancy, the potential presence of synchronous aneurysms, and the possible requirement for multiple interventions. Such surgery is prophylactic; consequently, surgical risk should be minimal. Open surgical repair of a PAA generally requires multiple incisions in the leg, dissection and disruption of the anatomy of the popliteal fossa, groin incisions, and a risk for wound and systemic complications. In one nationwide study of patients treated surgically for popliteal artery aneurysm, a 2% limb loss per year was documented following open surgical repair. There were significant rates of perioperative complications such as neurologic, infection, seroma, and hematoma.21 Open surgical repair of PAAs is associated with at least a 1.6% operative mortality rate.24 Despite open repair, there can be a 30% risk of aneurysmal expansion over time, even without obvious flow from geniculate branches. There is even potential for rupture of a previously bypassed PAA.35,38 Compartment syndrome has been reported as a long-term complication following bypass of a PAA.39 Postoperative leg swelling has been documented in over 50% of patients following bypass surgery.40 Various reports of bypass surgery in the leg have documented up to a 10% to 20% risk of surgical site infection.41 An endovascular approach to repair of a PAA is attractive because of the potential to minimize patient morbidity, duration of hospitalization, and recovery time. These are all important issues, particularly in a frail patient population that may require multiple interventions. However, the patency of endovascular stent grafts in the popliteal artery should not be inferior to that obtained with open bypass surgery. The feasibility of an endovascular approach to the management of patients with a PAA was demonstrated in early case reports and small clinical series.42-51 Although a variety of devices were described, most reported good early technical success without significant morbidity, no mortality, and short hospital stays. Concern was expressed, however, about the undocumented long-term patency of this new approach. The surgical data available on long-term outcome for open repair of PAAs is not large, given the relatively low incidence of the problem and the difficulty for any one center to accumulate a large experience. However, data does exist. Two relatively large contemporary case series of open surgical repair for 356 PAAs have documented 5-year primary patency rates of 75% to 85% for autogenous vein grafts.23,24 These rates compare favorably with a systematic review of literature that included 2,445 PAA repairs that
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demonstrated a range of 77% to 100% 5-year primary patency rate for vein grafts.1 Case series of endovascular PAA repair have suggested that these minimally invasive grafts may not have inferior patency results when compared with the historical controls for open surgical repair. A recent study of 23 endovascular procedures for PAAs demonstrated a 93% primary and 100% secondary 1-year patency rate.52 Another relatively large study of 35 PAAs demonstrated 75% 3-year primary patency and 83.2% secondary patency.53 In a larger study of 73 PAAs treated with endovascular therapy, Tielliu demonstrated 70% 5-year primary and 76% secondary patency rates.54 The 5-year primary patency rates improved over time to 80% with clinical experience and the addition of clopidogrel to postoperative patient management. A retrospective cohort study of open (n ⫽ 41) and endovascular (n ⫽ 15) PAA repair has demonstrated similar 1 to 2 year patency rates.29 These early data suggest at least noninferiority for patency rates for endovascular stent graft repair of PAAs compared with various traditional open surgical repairs. A prospective comparative study of open (n ⫽ 27) and endovascular (n ⫽ 21) repair demonstrated no primary or secondary patency differences out to 72 months of followup.55 This study included data from a randomized controlled study of open and endovascular popliteal aneurysm repair that did not demonstrate a patency difference between the two approaches out to 3 years of follow-up.30 Lovegrove has published a meta-analysis of all comparative studies of open (n ⫽ 104) and endovascular (n ⫽ 37) popliteal aneurysm repair. This study demonstrated similar patency rates between the two techniques, although the reintervention rate for endovascular grafts was higher than that required for open surgery. In summary, endovascular repair of PAAs has replaced open repair as the gold standard, as it has comparable patency without the associated local and systemic complications associated with open surgery. AUTHOR CONTRIBUTIONS Conception and design: AH, RM Analysis and interpretation: AH, RM Data collection: AH, RM Writing the article: AH, RM Critical revision of the article: AH, RM Final approval of the article: AH, RM Statistical analysis: AH, RM Obtained funding: N/A Overall responsibility: AH, RM REFERENCES 1. Dawson I, Sie RB, van Bockel H. Atherosclerotic popliteal aneurysm. Br J Surg 1997;84:293-9. 2. Henke PK. Popliteal artery aneurysms: tried, true, and new approaches to therapy. Semin Vasc Surg 2005;18:224-30. 3. Mousa AY, Beauford RB, Henderson P, Patel P, Faries PL, Flores L, Fogler R. Update on the diagnosis and management of popliteal aneurysm and literature review. Vascular 2006;4:103-8.
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4. Galland RB. Popliteal aneurysms: from John Hunter to the 21st century. Ann R Coll Surg Engl 2007;89:466-71. 5. Loukas M, Klaasen Z, Tubbs RS, Apaydin N. Popliteal artery aneurysms: a review. Folia Morphol (Warsz) 2007;66:272-6. 6. Wain RA, Hines G. A contemporary review of popliteal artery aneurysms. Cardiol Rev 2007;15:102-7. 7. Galland RB. History of the management of popliteal artery aneurysms. Eur J Vasc Endovasc Surg 2008;35:466-72. 8. Edwards WS. Exclusion and saphenous vein bypass of popliteal artery aneurysms. Surg Gynecol Obstet 1969;128:829-30. 9. Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg 1991;5: 491-9. 10. Parodi JC, Criado FJ, Barone HD, Schonholz C, Queral LA. Endoluminal aortic aneurysm repair using a balloon-expandable stent-graft device: a progress report. Ann Vasc Surg 1994;8:523-9. 11. Greenhalgh RM, Brown LC, Kwong GP, Powell JT, Thompson SG. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial. Lancet 2004;364:843-8. 12. Prinssen M, Verhoeven EL, Buth J, Cuybers PW, van Sambeek MR, Balm R, et al. A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med 2004;351: 1607-18. 13. Blankensteijn JD, de Jong SE, Prinssen M, van der Ham AC, Buth J, van Sterkenburg SM, et al. Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms. N Engl J Med 2005;352:2398-405. 14. Adam DJ, Beard JD, Cleveland T, Bell J, Bradbury Aw, Forbes JF, et al. Bypass versus angioplasty in severe ischaemia of the leg (BASIL): multicenter, randomised controlled trial. Lancet 2005;366:1925-34. 15. Almahameed A, Bhatt DL. Contemporary management of peripheral arterial disease: III. Endovascular and surgical management. Cleve Clin J Med 2006;73(Suppl 4):S45-51. 16. Singh KP, Patel MR, Kandzari DE, Zidar JP. Peripheral arterial disease: an overview of endovascular therapies and contemporary treatment strategies. Rev Cardiovasc Med 2006;7:55-68. 17. Mardikar HM, Mukherjee D. Current endovascular treatment of peripheral arterial disease. Prog Cardiovasc Nurs 2007;22:31-7. 18. White CJ, Gray WA. Endovascular therapies for peripheral arterial disease: an evidence-based review. Circulation 2007;116:2203-15. 19. Charing Cross Symposium News: online link. Available at: http:// cxnx.affinoworld.com/cxsymp/cxsymp.cfm?ccs⫽306. Accessed . 20. Johnson ON, Slidell MB, Macsata RA, Faler BJ, Amdur RL, Sidawy AN. Outcomes of surgical management for popliteal artery aneurysms: An analysis of 583 cases. J Vasc Surg 2008;48:845-51. 21. Ravn H, Wanhainen A, Bjorck M, Swedish Vascular Registry. Surgical technique and long-term results after popliteal artery aneurysm repair: results from 717 legs. J Vasc Surg 2007;46:236-43. 22. Beseth B, Moore WS. The posterior approach for repair of popliteal aneurysms. J Vasc Surg 2006;43:940-5. 23. Huang Y, Gloviczki P, Noel A, Sullivan T, Kalra M, Gullerud RE, et al. Early complications and long-term outcome after open surgical treatment of popliteal artery aneurysms: is exclusion with saphenous vein bypass still the gold standard? J Vasc Surg 2007;45:706-13. 24. Davies RS, Wall M, Rai S, Simms MH, Vohra RK, Bradbury AW, Adam DJ. Long-term results of surgical repair of popliteal artery aneurysm. Eur J Vasc Endovasc Surg 2007;34:714-18. 25. Gerasimidis T, Sfyroeras G, Papazoglou K, Trellopoulos G, Ntinas A, Karamanos D. Endovascular treatment of popliteal artery aneurysms. Eur J Vasc Endovasc Surg 2003;26:506-11. 26. Tielliu IF, Verhoeven EL, Prins TR, Post WJ, Hulsebos RG, van den Dungen JJ. Treatment of popliteal artery aneurysms with the Hemobahn stent-graft. J Endovasc Ther 2003;10:111-6. 27. Ranson M, Adelman MA, Cayne NS, Maldonado TS, Muhs B. Total Viabahn endoprosthesis collapse. J Vasc Surg 2008;47:454-6. 28. Tielliu IFJ, Verhoeven EL, Zeebregts CJ, Prins TR, Span MM, van den Dungen JJ. Endovascular treatment of popliteal artery aneurysms: results of a prospective cohort study. J Vasc Surg 2005;41:561-7.
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Submitted Sep 14, 2009; accepted Sep 15, 2009.
COMMENTARY
Thomas L. Forbes, MD, London, Ontario, Canada As endovascular stent grafts gained a firm foothold in the treatment of aortic aneurysms, we have seen the continued application of this therapy to aneurysmal disease in other vascular beds. The popliteal artery is no exception and offers unique challenges compared with the aorta. In the current debate, Drs Hill and Moore provide logical arguments for and against an endovascular approach to popliteal artery aneurysm (PAA) repair. There are several knowledge gaps regarding PAA management. First of all, little is known of the natural history of untreated aneurysms. As a result, any treatment recommendation based on aneurysm diameter is less robust than with aortic aneurysms. The indications for treatment differ as well, with PAAs rarely rupturing and more commonly causing thrombosis, embolization, or compressive symptoms. Most of these complications can be potentially prevented by open or endovascular repair. However, differing from the aorta, little has been described regarding PAA regression following endovascular repair. As a result, compressive symptoms caused by popliteal aneurysms are best treated with an open repair that includes sac decompression.
A consistent argument against new endovascular therapies is the relative absence of long term data, as Dr Moore clearly states. In this climate, it’s a wonder that any new endovascular technology takes hold as we continue to subject it to more intense surveillance than the open surgical “gold standard” and initially select higherrisk individuals to treat. Additionally, these evaluations occur when the technology is still maturing and, as Dr Hill states, the “gold standard” for open PAA repair is ill-defined and comprises several operations that could easily be the topic of another debate. For these reasons, the approximately similar patency and limb salvage rates with endovascular and open PAA repair is encouraging and generally offers support for an endovascular approach, rather than discouraging. A clear advantage of an endovascular approach is the reduction in the morbidity more often associated with open repair, namely local wound healing and infection-related complications. There is not much debate around this issue nor the reality that endovascular therapy of popliteal aneurysms is here to stay and is attractive to many of our patients.