(Radiographics. 2001;21:1248-1250.)
© RSNA, 2001
Invited Commentary • Authors' Response
Gerhard R. Wittich, MD
Alliance Radiology, Pasadena, Texas
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Commentary
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The incidence of critical leg ischemia worldwide has been estimated to range from 500 to 1,000 per 1 million persons per year (1). A Swedish study based on a longitudinal analysis of 321 patients identified a mean number of three surgical interventions per patient and a mean length of hospitalization of 117 days, resulting in significant health care costs (2).
The aim of treatment is patient survival and limb salvage. Therapeutic options include open surgery and radiologic transcatheter therapies such as thrombolysis, angioplasty, and thrombectomy. In a recent review of treatment strategies for acute lower-extremity ischemia, Kasirajan and Ouriel (3) stressed that at present, no single open surgical or endovascular treatment modality can be considered the standard of reference. The TOPAS trial—a randomized, multicenter study that compared local thrombolysis with surgery—showed similar amputation-free 6-month survival rates for both types of therapy (71.8% and 74.8%, respectively) (4). Similarly, a long-term prospective randomized study comparing bypass surgery with femoropopliteal angioplasty in patients with chronic limb ischemia found no statistical difference between these two methods (5).
Regardless of the type of therapy, the interventional radiologist is usually consulted to perform diagnostic angiography, which should include detailed imaging of the plantar arch (6). An algorithm proposed by Kasirajan and Ouriel (3) advocates initial treatment with mechanical transcatheter thrombectomy with one of several available devices (eg, Angiojet rheolytic catheter [Possis Medical, Minneapolis, Minn], Hydrolyser [Cordis, Warren, NJ], Oasis device [Boston Scientific, Boston, Mass]) for rapid debulking of thrombus. This may be followed by low-dose, short-duration local thrombolytic therapy. Any residual underlying stenoses may then be treated with angioplasty and stent placement or with elective open surgery (3).
Despite such an optimized, multidisciplinary approach, a subgroup of patients—14%–20% according to the preceding article by Engelke et al (7)—are unsuited for distal arterial reconstruction and may therefore require amputation. Few effective therapeutic options are available to these patients, who usually suffer from advanced disease of small vessels of the calf and foot and who may be further compromised by diabetic nephropathy or severe coronary artery disease. Chemical lumbar sympathectomy (8), spinal cord stimulation (9), or intravenous administration of pentoxifylline (1)—a drug that inhibits leukocyte aggregation and improves oxygen release to tissue—may all be of value as adjunct therapeutic measures, but aggressive surgical management with distal venous arterialization as described by Engelke et al may be the single most promising interventional procedure for averting amputation in a significant segment of this patient population. A limb salvage rate of 75% at 2-year follow-up is certainly a remarkable achievement in a group of patients with Fontaine stage IV critical lower limb ischemia, who are not suited for endovascular treatment or standard bypass surgery (7). The role of the radiologist in this team effort is to provide and interpret pre- and intraoperative venograms in addition to arteriograms. These venograms are important for planning the surgical approach and documenting effective surgical removal of valves.
If the results of Engelke et al can be duplicated by other groups and in larger series, this procedure will broaden the spectrum of therapeutic options available to patients with critical leg ischemia.
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References
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Colgan MP, Moore DJ, Shanik GD. Pentoxifylline and critical leg ischemia. J Cardiovasc Pharmacol 1995; 25(suppl 2):S58-S60.
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Eneroth M, Apelqvist J, Troeng T, Persson BM. Operations, total hospital stay and costs of critical leg ischemia: a population-based longitudinal outcome study of 321 patients. Acta Orthop Scand 1996; 67:459-465.[Medline]
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Kasirajan K, Ouriel K. Management of acute lower extremity ischemia: treatment strategies and out-come. Curr Intervent Cardiol Rep 2000; 2:119-129.[Medline]
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Ouriel K, Veith FJ, Sasahara AA. A comparison of recombinant urokinase with vascular surgery as initial treatment for acute arterial occlusion of the legs. N Engl J Med 1998; 338:1105-1111.[Abstract/Free Full Text]
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Wolf GL, Wilson SE, Cross AP, Deupree RH, Stason WB. Surgery or balloon angioplasty for peripheral vascular disease: a randomized clinical trial. J Vasc Interv Radiol 1993; 4:639-648.[Medline]
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Lundell A, Bergqvist D, Cederholm C. Patency of the plantar arch as a prognostic indicator in patients with critical leg ischemia: a retrospective study. Eur J Surg 1993; 159:625-629.[Medline]
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Engelke C, Morgan RA, Quarmby JW, Taylor RS, Belli AM. Distal venous arterialization for lower limb salvage: angiographic appearances and interventional procedures. RadioGraphics 2001; 21:1239-1250.[Abstract/Free Full Text]
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Greenstein D, Brown TF, Kester RC. Assessment of chemical lumbar sympathectomy in critical limb ischaemia using thermal imaging. Int J Clin Monit Comput 1994; 11:31-34.[Medline]
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Ubbink DT, Jacobs MJ. Spinal cord stimulation in critical limb ischemia: a review. Acta Chir Belg 2000; 100:48-53.[Medline]
Authors’ Response
Christoph Engelke, MD,
Robert A. Morgan, FRCR and
Anna-Maria Belli, FRCR
Department of Radiology, John W. Quarmby, FRCS, Robert S. Taylor, FRCS, Department of Vascular Surgery, St George’s Hospital, London, England
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Response
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The clinical prognosis for patients who present with critical leg ischemia is poor. Despite the extensive use of endovascular and surgical revascularization procedures in highly specialized, aggressive treatment units, the primary amputation rate for critical leg ischemia varies from 10% to 40% (1–3). The total estimated number of major amputations performed in patients with critical leg ischemia is about 15,000 per year in the United Kingdom (4,5). This compares with 250–500 per 1 million persons per year in various European countries (5–7) and about 280 per 1 million persons per year in the United States (8). Most of these patients are over 60 years old, and 70% have serious concomitant cardiorespiratory morbidity. The perioperative mortality for major amputation in these patients is about 10%. Within 2 years, 30% of patients who undergo below-knee amputation will die, 15% will require a contralateral major amputation, and another 15% will require above-knee amputation (4,5,9). Clearly, the current treatment modalities, which are targeted at modifying the high morbidity and mortality of critical leg ischemia, are not particularly successful, and there is no effective means of reducing the number of amputations performed in this subgroup of patients, who present with critical leg ischemia and unreconstructible underlying arterial disease.
Our study was initiated by our vascular surgeons to evaluate the technical feasibility of distal venous arterialization in patients with critical leg ischemia who are unsuited for endovascular therapy or surgical vascular reconstruction (10,11). The resulting surgical technique, a hybrid of endovascular and classical vascular surgical procedures, evolved from the need to break down venous valves in the foot and was developed in cooperation with the vascular interventionalradiologists in our radiology department. Surgery now takes about 3–5 hours if performed by two experienced consultant vascular surgeons.
Venous arterialization requires extensive invasive and noninvasive pre-, intra-, and postoperative radiologic work-up performed with the described procedures and in close cooperation with our colleagues in surgery. Digital subtraction angiography combined with duplex US proved invaluable in the assessment of affected patients. The purpose of our article was to familiarize radiologists with the imaging appearances of patients undergoing venous arterialization procedures and present the key digital subtraction angiography features of the current surgical techniques, possible complications, and management options.
The endovascular ablation of venous valves with currently available mechanical instruments is still problematic and needs improvement. The valves are difficult to identify due to their small size and delicate structure, and imaging techniques with very high local resolution such as intravascular US that make use of small-caliber, flexible probes could significantly improve the intraoperative guidance of mechanical valve destruction devices and expand the role of intraoperative radiologic procedures in the future.
If the initial results of distal venous arterialization can be confirmed in larger-scale trials, this treatment could become very valuable for patients with critical ischemia and otherwise unsalvageable limbs.
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References
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Ouriel K, Fiore WM, Geary JE. Limb-threatening ischemia in the medically compromised patient: amputation or revascularization?. Surgery 1988; 104:667-672.[Medline]
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Hickey NC, Thomson IA, Shearman CP, Simms MH. Aggressive arterial reconstruction for critical lower limb ischaemia. Br J Surg 1991; 78:1476-1478.[Medline]
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Dormandy J, Heeck L, Vig S. The fate of patients with critical leg ischaemia. Semin Vasc Surg 1999; 12:142-147.[Medline]
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Dormandy JA, Rutherford RB. Management of peripheral arterial disease (PAD): TASC Working Group—TransAtlantic Inter-Society Consensus (TASC). J Vasc Surg 2000; 31(1 pt 2):S1-S296.[Medline]
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Dormandy JA, Ray S. The natural history of peripheral arterial disease. In: Tooke JE, Lowe GD, eds. A textbook of vascular medicine. London, England: Arnold, 1996; 162-175.
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Nogren L. Definition, incidence and epidemiology. In: Dormandy JA, Stock G, eds. Critical leg ischaemia: its pathophysiology and management. Berlin, Germany: Springer-Verlag, 1990; 7-13.
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Ebskov LB, Schroeder TV, Holstein PE. Epidemiology of leg amputation: the influence of vascular surgery. Br J Surg 1994; 81:1600-1603.[Medline]
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Kacy SS, Wolma FJ, Flye MW. Factors affecting the results of below knee amputation in patients with and without diabetes. Surg Gynecol Obstet 1982; 155:513-518.[Medline]
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Ebskov B. Relative mortality and long term survival for the non-diabetic lower limb amputee with vascular insufficiency. Prosthet Orthot Int 1999; 23:209-216.[Medline]
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Taylor RS, Belli AM, Jacob S. Distal venous arterialisation for salvage of critically ischaemic inoperable limbs. Lancet 1999; 354:1962-1965.[Medline]
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Engelke C, Morgan RA, Quarmby JW, Taylor RS, Belli AM. Distal venous arterialization for lower limb salvage: angiographic appearances and interventional procedures. RadioGraphics 2001; 21:1239-1250.
Related Article
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Distal Venous Arterialization for Lower Limb Salvage: Angiographic Appearances and Interventional Procedures
- Christoph Engelke, Robert A. Morgan, John W. Quarmby, Robert S. Taylor, and Anna-Maria Belli
RadioGraphics 2001 21: 1239-1248.
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