Claudication: Treatment Options for Femoropopliteal Disease Martin Schillinger , Erich Minar ⁎
Transcription
Claudication: Treatment Options for Femoropopliteal Disease Martin Schillinger , Erich Minar ⁎
Progress in Cardiovascular Diseases 54 (2011) 41 – 46 www.onlinepcd.com Claudication: Treatment Options for Femoropopliteal Disease Martin Schillinger⁎, Erich Minar Department of Angiology, Medical University, Vienna, Austria Abstract Intermittent claudication due to chronic femoropopliteal obstruction is a common disease, and patients are potentially severely disabled by the painful limitation of walking capacity. Despite major advances in pharmacological therapy of atherosclerosis, effective medication specifically for treatment of intermittent claudication is still not available. Training programs work well for patients with mild to moderate symptoms but frequently fail in patients with very compromised walking capacity. Patients with severe symptoms and markedly reduced quality of life therefore are candidates for revascularization. The preferred method of revascularization is endovascular treatment; this includes simple balloon angioplasty, debulking techniques, stent implantation, and, more recently, drug eluting technologies. Selected patients are candidates for surgery which encompasses endarterectomy of focal common femoral lesions as well as femoropopliteal bypass surgery in patients with very extensive disease or after failed endovascular approaches. The following article reviews current aspects of the management of femoropopliteal disease in patients with intermittent claudication. (Prog Cardiovasc Dis 2011;54:41-46) © 2011 Elsevier Inc. All rights reserved. Keywords: Claudication; Femoropopliteal disease; Treatment Intermittent claudication due to chronic femoropopliteal disease occurs relatively frequently in the population 60 years and older and can be a severely disabling condition. Different treatment options are available, depending on patients' symptoms and their reduction in the quality of life. Irrespective of clinical stage, all patients with peripheral artery disease require best medical treatment to prevent complications of atherosclerosis; this includes platelet inhibitors, statins, and usually antihypertensive and glucose-lowering medication. However, these medications have only a minor effect, if any at all, on walking capacity, and only patients with very mild symptoms will be adequately treated with these medications only. Statement of Conflict of Interest: see page 46. ⁎ Address reprint requests to Martin Schillinger, MD, Division of Angiology, Department of Internal Medicine II, Vienna General Hospital, Medical University, Waehringer Guertel 18-20, A-1090 Vienna, Austria, Europe. Tel.: +43 1 40400 4670; fax: +43 1 40400 4665. E-mail address: [email protected] (M. Schillinger). 0033-0620/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.pcad.2011.04.003 Walking training, particularly using supervision and training programs, has tremendous effects in certain subgroups of patients with intermittent claudication. However, it frequently fails in patients with severely limited walking capacity. The heterogeneous group of vasoactive drugs is meant to improve peripheral perfusion, but the net effect of most of these drugs has to be judged very critically. Patients with very short pain-free walking distance are candidates for revascularization. However, the femoropopliteal segment is a challenging vascular territory. The superficial femoral artery (SFA) is the longest artery in the human body and is fixed between two major flexion points, the hip and the knee. During movements like walking or stair climbing, various forces are exerted on this vessel, including flexion, longitudinal, and lateral compression and torsion. Furthermore, the artery dives through a major muscle group at the site of the Hunter's canal leading to additional external compression during muscular work. Differing from iliac arteries, the anatomy of the vascular wall in the femoropopliteal segment is characterized by an increased density of vascular smooth muscle cells. 41 42 M. Schillinger, E. Minar / Progress in Cardiovascular Diseases 54 (2011) 41–46 Abbreviations and Acronyms Response to injury by extensive scar formation CTO = Chronic total leading to recurrent disocclusion ease is a specific feature of muscular arteries. Furthermore, particularly in the femoropopliteal segment, atherosclerotic disease is usually characterized by a diffuse and heavy calcification of long vascular segments. Nevertheless, today, the preferred method of revascularization in many patients is minimally invasive endovascular treatment; this includes balloon angioplasty, debulking techniques, stent implantation, and, more recently, drug-eluting technologies. Whenever technically possible, endovascular treatment offers the advantage of low complication rates, short hospitalization, and rehabilitation due to a low post-interventional morbidity risk.1,2 The Achilles heel of endovascular treatment remains long-term patency, particularly in patients with certain risk factors and lesion morphologies. Selected patients therefore are primarily candidates for surgery, which includes endarterectomy and profundaplasty of focal common femoral lesions as well as femoropopliteal bypass surgery in patients with very extensive disease or after failed endovascular approaches.1,2 Treatment options for claudicants with femoropopliteal disease Exercise training Systematic exercise training has the potential to dramatically improve patients' exercise capacity. Unstructured training—just based on the physician's recommendation to start walking—has very little or almost no effect on the symptoms of intermittent claudication. Training sessions should start with approximately 30 minutes and then be increased to 1 hour. The intensity of the training has to be structured to induce intermittent claudication in 3- to 5-minute intervals. Exercise is stopped at a level of moderate claudication and resumed as soon as the pain is gone. These cycles of exercise and rest should be between 35 and 50 minutes. Speed and treadmill grade can be modified, but it is recommended to achieve a walking speed of 3.0 mph (4.8 km/h) and then further increase the grade. There are comorbid conditions which prohibit training in 10% to 30% of the patients within studies. In clinical practice, however, availability of the training programs is the main limitation. A summary of the evidence of exercise training in patients with intermittent claudication is given in the TransAtlantic Inter-Society Consensus II document.2 Vasoactive drugs This is a very heterogeneous group of medication meant to improve peripheral perfusion. A variety of drugs are on the market, but very few have been proven effective in randomized studies, Cilostazol is a phosphodiesterase III inhibitor with vasodilator, metabolic and antiplatelet activities. In a meta-analysis,3 the net effect of Cilostazol is an improvement of walking capacity on the treadmill of 50 to 70 m; side-effects include head ache, diarrhea, and palpitations. Cilostazol is contraindicated in patients with congestive heart failure. Naftidrofuryl is a 5 hydroxtryptamine type 2 antagonist which may improve muscle metabolism and reduce erythrocyte and thrombocyte aggregation. A meta-analysis including 888 patients showed a 26% improvement of walking capacity compared to placebo without significant increase of side effects.4 Buflomedil was recently demonstrated in a single randomized trial including 2078 patients with peripheral artery disease to reduce cardiovascular events by 26% and improve ankle-brachial index by 9% given over a 33month period.5 Prostanoids The efficacy of prostanoids for patients with intermittent claudication is unclear. A Cochrane systematic review identified 18 studies for this indication, but because of a significant heterogeneity, no meta-analysis was possible.6 Intravenous administration of prostaglandin E1 improved patients' walking capacity, whereas oral prostacyclin analogs or intravenous prostacyclin was not effective in patients with intermittent claudication. For many other drugs, effectiveness has not been proven, and therefore, these drugs are definitively not recommended. Owing to overall minimal effects, in our personal practice, the use of all vasoactive medication including the drugs mentioned above in patients with intermittent claudication is generally avoided. Endovascular treatment Patients with severe limitation of their walking capacity and quality of life are definitively candidates for revascularization procedures. Minimal invasive endovascular treatment offers several advantages, including the extremely low mortality and morbidity of the procedures. Its main limitation remains patency. Recently, significant progress has been made in improving both recanalization rates and midterm patency. Recanalization technique The use of dedicated chronic total occlusion catheters currently enables recanalization of almost all lesions. Personal experience and several reports from high-volume centers confirm a success rate above 95% even in very long and calcified femoropopliteal lesions using, for example, the Outback Catheter System (Fig 1) (Cordis, Johnson&Johnson, New Brunswick, NJ). Additionally improved chronic total occlusion wire technology and the use of hydrophilic support catheters facilitate complex femoropopliteal procedures. Last but not least, advanced access methods like transpopliteal or transpedal access routes help M. Schillinger, E. Minar / Progress in Cardiovascular Diseases 54 (2011) 41–46 43 Fig 1. A, Angiographic occlusion (arrow) of the left superficial femoral artery (SFA). B, The outback catheter is advanced through the occlusion (arrow). C, Angiogram of the recanalized proximal SFA. D, Angiogram of the distal recanalized SFA. to guarantee successful outcomes in certain complex anatomies. Patency Restenosis rate after femoropopliteal balloon angioplasty range between 40% in short lesions up to 80% in long lesions at 12 months postintervention. Given this fairly high failure rate particularly in lesions with a length above 10cm the appropriateness of plain balloon angioplasty in this indication has to be questioned. The application of nitinol stent technology significantly improved the durability of stenting in intermediate length femoropopliteal lesions. In the ABSOLUTE trial in 104 patients with severe claudication and 10 cm SFA stenosis or occlusion, the restenosis rates were reduced from 63.5% to 36.7% at 12 months by primary stenting (Fig 2), which resulted also in a significantly improved walking capacity on the treadmill.7 Nevertheless, a 2-year rate of restenosis in the primary stent arm (46%) leaves room for improvement.8 In contrast, the results of FAST (Femoral Artery Stenting Trial) including 244 patients with a mean lesion length between 4 and 5 cm showed no benefit of primary stenting at 12 months (restenosis rate 32% vs. 39% in the stents vs the balloon angioplasty groups).9 Nevertheless, further studies like the RESILIENT and ASTRON trials confirmed the initial results underlining that nitinol stents improve midterm outcomes in intermediate-length lesions but remain a nonsatisfying treatment option with respect to long term patency. Meanwhile, initial problems with fractures of first generation nitinol stents also were resolved. Meanwhile, stent grafts have a renaissance as results of these devices in extremely long lesions (average 25 cm) were equivalent to prosthetic bypass surgery in recent studies,10 and complication rates were dramatically 44 M. Schillinger, E. Minar / Progress in Cardiovascular Diseases 54 (2011) 41–46 Fig 2. Left panel shows a baseline left superficial femoral artery stenosis. Center panel shows the result of successful stent (arrows) placement. Right panel shows 6 month follow-up angiography. decreased due to lower profile introducer sizes. Nevertheless, it remains to be determined whether the mechanical properties of these devices can withstand the forces exerted in the femoropopliteal segment and whether the problem of edge stenosis and subsequent stent graft thrombosis can be resolved by an active (heparin) coating of the devices. Addressing alternative balloon technologies, after failure of other balloon technologies such as cutting balloon or cryoplasty, early studies with drug-eluting balloons showed improved femoropopliteal patency rates without leaving an implant in the vessel.11 In the 3-arm THUNDER trial, 154 patients with short femoropopliteal lesions (around 7 cm) were randomized to undergo either plain balloon angioplasty with a standard balloon, balloon angioplasty with a paclitaxel coated balloon, or with a standard balloon and paclitaxel in the contrast medium. Restenosis at 6 months was significantly reduced by the paclitaxel eluting balloon (4%) compared to the standard balloon groups with (29%) or without (37%) paclitaxel in the contrast medium. Several studies are currently ongoing to reproduce these promising results. Nevertheless, the problems of elastic recoil, heavy calcification, and residual stenosis after balloon angioplasty of long and complex lesions likely cannot be resolved by the drug-coated balloon approach. In the field of promising technologies, drug-eluting stents for long lesions generated hope for better outcomes but, in fact, had very disappointing results. The SIROCCO I study at 6 months12 showed 0% restenosis but even together with SIROCCO II13 was underpowered to show a benefit compared to the bare stent. The STRIDES study was a single-arm prospective study using a more potent everolimus eluting self-expanding stent and showed disappointing 12 months of restenosis results, and the product will not be further developed. So, until very recently, drug-eluting stents in the femoropopliteal segment seemed a failure. The 12-month results of the randomized ZILVER trial included 479 patients with an average lesion length of 5 cm who were randomized to balloon angioplasty versus stenting using a polymer-free paclitaxel-eluting stent. Patients in the balloon angioplasty group with a suboptimal result after balloon only were further randomized to secondary stenting using a bare or a drug-eluting stent. Using a rather conservative definition of restenosis by ultrasound (peak velocity ratio above 2.0), the paclitaxeleluting stent showed a significantly improved restenosis rate at 12 months (17%) compared to optimal balloon angioplasty (35%) as well as balloon angioplasty with provisional stenting (33%). The stent had a very low 12month fracture rate (0.9%). It remains to be investigated whether these results can be reproduced in all patient subgroups and whether patency is maintained after long follow-up. Currently, these results seem the best that can be achieved in the femoropopliteal segment. Biodegradable stents seem a concept worth being further investigated. The main problem currently is the unsatisfactory mechanical properties both of metallic (magnesium-based) or polymeric-based biodegradable materials. Radial force of the tested devices remains problematic for the femoropopliteal segment, and true selfexpanding properties hardly can be achieved by the current investigational devices. M. Schillinger, E. Minar / Progress in Cardiovascular Diseases 54 (2011) 41–46 Surgery Bypass surgery using vein grafts still gives the best long-term results for long femoropopliteal lesions with patency rates around 70% at 5 years.1,2 However, an increased morbidity and mortality of the procedure as compared to the endovascular approach always has to be weighted against the good long-term results. Furthermore, data are less favorable if prosthetic graft material has to be used. In these patients 5-year reocclusion rates around 50% have to be expected.1 In personal practice, patients' age and life expectancy and the operation risk from a general medical perspective seem the most important determinants whether a patient with a long femoropopliteal lesion should primarily undergo surgery or whether the endovascular approach is justified. Highly calcified common femoral artery obstructions frequently respond very poorly to endovascular treatment, in these 45 patients common femoral endarterectomy is the treatment of choice. Summary and conclusion Treatment options for patients with intermittent claudication and femoropopliteal disease include pharmacologic treatment and exercise training, endovascular therapy and surgery (Fig 3). Best medical treatment is mandatory for all patients with peripheral artery disease to beneficially influence patients' overall prognosis. Patients with mild or moderate claudication are, in the absence of contraindications, good candidates for supervised exercise training. Patients with severe claudication and severe limitation of their quality of life should undergo revascularization. Endovascular treatment generally is the method of first choice in these patients. Patients with long obstructions or Fig 3. Treatment algorithm for patients with intermittent claudication due to femoropopliteal obstructions. 46 M. Schillinger, E. Minar / Progress in Cardiovascular Diseases 54 (2011) 41–46 after failure of endovascular procedures should be considered for surgery. 6. 7. Statement of Conflict of Interest All authors declare that there are no conflicts of interest. References 1. Dormandy JA, Rutherford RB: Management of peripheral arterial disease (PAD). TASC Working Group. TransAtlantic Inter-Society Consensus (TASC). J Vasc Surg 2000;31:S1-S296. 2. 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