In 2005 the Charing Cross meeting sought to achieve a consensus, “Towards Vascular and Endovascular Consensus”, having identified “Vascular and Endovascular Controversies” (2003) and “Challenges” (2004). A “Consensus” document was published soon after and reported the preferred imaging modality and preferred treatment option (surgical or endovascular) lesion by lesion.
Recently, Professor Johannes Lammer, University of Vienna, presented the 2006 TransAtlantic Inter-Society Consensus (TASC) recommendations at the recent Olbert Workshop in Vienna, Austria. TASC is an organisation that strives to promote a uniformly high level of atherosclerotic disease management across different countries.
According to TASC, there is currently a huge variation in medical care, not only from country to country but also among states and hospitals. By formulating a consensus of expert opinion from key professional societies (such as the European Society for Vascular Surgery, the American College of Cardiology, the Society for Vascular Surgery and the Cardiovascular and Interventional Radiology Society of Europe, Society of Interventional Radiology, among many others), TASC has developed a consensus document that aims to optimise and maintain international medical standards, reflecting the latest developments in technology and techniques.
To achieve an in-depth consideration of the topic, the latest transatlantic inter-society document recommendations concern the management of peripheral arterial occlusive disease (PAOD) as a result of atherosclerosis affecting the lower limbs only and seeks to aid the physicians when selecting suitable treatment.
Lammer told Vascular News, “These are very good guidelines for vascular physicians in how they should treat their patients, as the documents highlight the prevalence and co-morbidities of vascular diseases and review the results of conservative and invasive treatment.”
TASC recommendations
He began by discussing the non-invasive localisation of lesions in the document (Recommendation 38), stating that if a physician wishes to localise and gauge the severity of occlusive arterial lesions to assist in planning an intervention, then Duplex ultrasound, magnetic resonance angiography, and, more recently, computed tomography can be used as a preliminary, non-invasive examination before angiography. He stressed that anatomic localisation must only be considered in patients deemed suitable candidates for revascularisation, either via surgical or endovascular means.
Lammer said that in a situation where endovascular revascularisation and open repair of a specific lesion causing symptoms of PAD give equivalent short-term and long-term improvement, the technique with the least morbidity and mortality must be used first (Recommendation 29).
Unless otherwise indicated, Lammer said the preferred treatment of type A and B lesions is generally endovascular, whereas the treatment of type C lesions can be endovascular or surgical: the risks, benefits, durability and therapeutic goals must be considered for the individual patient. Concerning type D lesions, he said the treatment is generally surgical, although endovascular repair may be considered in certain cases.
The next recommendation (Recommendation 30) concerns the morphologic stratification of aorto-iliac lesions. TASC type A iliac lesions are defined as: single short stenoses of the common iliac artery or external iliac artery (unilateral/bilateral). In addition, TASC type B iliac lesions were defined as: single long stenoses involving the common iliac artery and/or external iliac artery not extending into the common femoral artery; bilateral long stenoses involving the common iliac artery and/or external iliac artery not extending into the common femoral artery; and single occlusion of the common iliac artery or external iliac artery not extending into the common femoral artery.
Furthermore, Lammer said that morphologic stratification of TASC type C aorto-iliac lesions were defined as: bilateral occlusion of the common iliac artery or external iliac artery not extending into the common femoral artery; and iliac stenoses in a patient with an abdominal aortic aneurysm. For TASC type D lesions, the definitions were: unilateral or bilateral external iliac artery stenoses extending into the common femoral artery; unilateral occlusion involving both the common iliac artery and external iliac artery; diffuse stenotic disease involving the aorta and both iliac arteries in a young, normal risk patient; and infrarenal aorto-iliac occlusions.
Morphologic stratification of femoropopliteal lesions (Recommendation 31) for TASC type A were defined as single stenoses/occlusion <10cm (unilateral/bilateral) not involving the trifurcation. In addition, TASC type B femoropopliteal lesions were defined as: multiple stenoses or occlusions <5cm each not involving the trifurcation; single stenoses or occlusion <15cm not involving the trifurcation; and single or multiple lesions in the absence of continuous tibial run-off to improve inflow for distal surgical bypass. TASC type C femoropopliteal lesions were defined as: heavily calcified common femoral artery stenoses; heavily calcified stenoses or occlusions >15cm in length; and recurrent stenoses or occlusions after one redo. Finally, TASC type D femoropopliteal lesions were defined as: complete common femoral artery occlusion; complete SFA occlusion in excess of 20cm; and complete popliteal artery and proximal trifurcation occlusion.
Lammer then revealed recommendations related to antiplatelet drugs as adjuvant pharmacotherapy (Recommendation 35). After revascularisation antiplatelet therapy should be started preoperatively and continued as adjuvant pharmacotherapy after an endovascular or surgical procedure.
Unless subsequently contraindicated, this should be continued indefinitely.
In addition, he commented that surveillance may be beneficial in order to identify a lesion on which to intervene on restenosis to prevent secondary occlusion (Recommendation 36).
When asked which recommendation he believed was the most significant, Lammer commented, “I think the most important recommendation is that we should opt to choose the least invasive techniques. In addition, and this is different to previous guidelines, the recommendations take into account the wishes of the patient. It is very important that the patient is involved in the decision-making process.”
Future recommendations
“I think what we are waiting for is recommendations regarding the use of stents. A randomised study we carried out in Vienna (ABSOLUTE Study), which compared PTA and stenting in the femoropopliteal arteries, showed that at the mid-term the patency rates for patients who received stents were significantly better than those who did not.”
Lammer stressed that these are “only recommendations and that minor changes may be added. Then they must be finally approved by all societies. We expect to publish the guidelines in the summer.”
Femoropopliteal lesions
At CX 2005, endovascular treatment was favoured for mandatory indications of critical ischaemia and incapacitating claudication for TASC A,B and C lesions ahead of surgery because of lower mortality and morbidity reports. It was confirmed that there is no high level evidence of adjuvant benefit in terms of AWD at two years from PTA with or without stent beyond supervised exercise.
Nevertheless, practice is moving ahead of evidence and the consensus is that in future even TASC D lesions will become the domain of endovascular rather than open surgery which remains the present favourite for TASC D femoropopliteal lesions.
As the European Vascular and Endovascular Monitor repeatedly demonstrates (book 2005), there is a relentless change of practice across the board towards endovascular options and away from traditional surgery.
Highlights from 2005 Consensus document
Summary of Trans Atlantic Society’s Consensus (2000) aortoiliac lesions
TASC Type A Iliac lesions:
TASC Type B Iliac lesions:
TASC Type C Iliac lesions:
TASC Type D Iliac lesions:
Aortoiliac lesions TASC A and B
By consensus these lesions are considered together. The only ongoing benefit of separating TASC A and TASC B is to potentially for reporting purposes, where A lesion may have a better natural history. From the imaging and management point of view they can be combined.Imaging options
The consensus was that the presence or absence of a femoral pulse is a crucial determinant for imaging preference. If it is present duplex ultrasound evaluation precedes IADSA if endovascular is to be used. Therefore, the procedure is designed based on the duplex scan and re-evaluated at the time of possible correction, which is preceded by diagnostic IADSA. In the absence of a femoral pulse consideration is given first to the CEMRA to evaluate possibilities.
Vascular and endovascular options
Endovascular is by consensus the first choice option for TASC A and B lesions. Before consideration of surgery, the consensus was that because of higher mortality risk of aortic surgery, three endovascular failures would first trigger consideration of surgery; fitness of the patient, severity of symptoms and distribution of disease the unilateral or bilateral comes into the decision making.
By consensus, surgeon, interventionalist and radiologist should meet in a multi-disciplinary regular session for planning optional procedures. For example, many major open procedures can be avoided if only one side is corrected by an endovascular method with or without stent. Femoro-femoral crossover bypass through two small groin incisions is minor surgery indeed and can be done under local anaesthetic if needed. The consensus was to reconstruct as much as possible via endovascular methodology. The use of stent remains controversial and some say it is best performed “by instinct”. There remains no doubt that arterial reconstruction provides the best five year long term patency option but the quality of life issue and lower morality risk tilt conclusively to endovascular preference.
Aortoiliac lesions TASC C
Imaging options
The consensus was that the presence or absence of a femoral pulse is a crucial determinant for imaging preference. If it is present duplex ultrasound evaluation precedes IADSA if endovascular is to be used. Therefore, the procedure is designed based on the duplex scan and re-evaluated at the time of possible correction, which is preceded by diagnostic IADSA. In the absence of a femoral pulse consideration is given first to the CEMRA to evaluate possibilities.
Vascular and endovascular options
The aorto-bifemoral Dacron bypass carries a 90% five-year patency expectation at a mortality risk.
What is the risk? Although there are good single centre reports, there are fewer large national registry data figures available and reports of at least 6% 30-day mortality have been reported for aorto-iliac surgical intervention. Therefore, again fitness for the patient and the patient’s views comes into the frame. Bigger arteries in general do better than smaller arteries, eg common iliac arteries have a better outcome than external iliac artery outcomes. Stents are favoured for iliac occlusions. The consensus was in favour of endovascular almost always as first choice even with a 65-75% five year patency rate, which is significantly lower than surgical patency. For bilateral common iliac occlusions in a fit patient, surgery remains a good option with patient support.Aortoiliac lesions TASC D
Imaging options
The consensus was that the presence or absence of a femoral pulse is a crucial determinant for imaging preference. If it is present duplex ultrasound evaluation precedes IADSA if endovascular is to be used. Therefore, the procedure is designed based on the duplex scan and re-evaluated at the time of possible correction, which is preceded by diagnostic IADSA. In the absence of a femoral pulse consideration is given first to the CEMRA to evaluate possibilities.
Vascular and endovascular options
The patient’s opinion should be vital in this category. There is consensus to make aorto-bifemoral Dacron bypass surgery first choice in the fit patients who have severe bilateral disease. The consensus was to favour femoro-femoral crossover bypass for severe unilateral disease and endovascular as first choice for bilateral disease in an unfit patient. Intervention is either mandatory for critical ischaemia or severe capacitating intermittent claudication, but for Mild to Moderate Intermittent Claudication, the adjuvant benefit of any angioplasty with or with stent is tested in the ongoing “MIMIC” trial. Therefore, in this situation there is no evidence to support the efficiacy of angioplasty with or without stent over supervised exercised alone, let alone against bypass surgery.
Profunda artery stenosis
Imaging options
Expert duplex colour ultrasonography is all that is required if it is available. CE CTA and CEMRA are there for confirmation. The consensus was that diagnostic arteriography is very seldom needed nowadays for profunda or femoropopliteal investigation but it remains the gold standard and is particularly helpful for tibial disease evaluations.
Vascular and endovascular options
Since the DeBakey group drew our attention to the “surgical importance of the profunda femoris” in 1969, direct surgery has been and remains first choice, under local anaesthetic if necessary. Endovascular access is awkward and often requires contralateral femoral or axillary access. The consensus was for open operative correction by endarterectomy. This can easily combine, if necessary, with an upstream endovascular inflow procedure or a downstream subintimal angioplasty of the superficial femoral artery.
Summary of the Trans Atlantic Society’s Consensus (2000) femoropopliteal lesions
TASC Type A Femoropopliteal lesions:
TASC Type B Femoropopliteal lesions:
TASC Type C Femoropopliteal lesions:
TASC Type D Femoropopliteal lesions:
Femoropopliteal stenosis TASC A & B
Imaging options
Expert duplex colour ultrasonography is all that is required if it is available. CE CTA and CEMRA are there for confirmation. The consensus was that diagnostic arteriography is very seldom needed nowadays for profunda or femoropopliteal investigation but it remains the gold standard and is particularly helpful for tibial disease evaluations.Vascular and endovascular options
The fitness of the patient and severity of symptoms, whether unilateral or bilateral, and whether the patient smokes enter the decision process. Chronic limb ischaemia, critical ischaemia, rest pain, tissue loss and risk imminent amputation are indications for mandatory intervention, as is incapacitating intermittent claudication in a fit patient. There is no reliable evidence favouring angioplasty in the femoropopliteal segment and many use stents only to get out of trouble. These A and B lesions on their own would be unlikely to cause anything more severe than intermittent claudication. Usually rest pain is not caused by such mild lesions alone.
There is evidence of benefit in terms of absolute walking distance at two years for femoropopliteal angioplasty. The consensus was that intermittent claudication should be used as the marker of cardiovascular disease elsewhere and future increased cardiovascular risk, e.g. heart attack or stoke as well as lower limb incapacity. Thus supervised exercise, smoking cessation advice, diabetes control, hypertension control, the use of statins and the use of platelet-inhibitor therapy by consensus should precede endovascular intervention or surgical intervention. It remains to be proved if angioplasty is of adjuvant benefit over supervised exercise and best medical treatment in Mild to Moderate Intermittent Claudication. The “MIMIC” trial is powered separately for the aortoiliac and femoropopliteal segments.
Any mandatory intervention for chronic limb ischaemia and critical ischaemia or incapacitating claudication could be bypass or remote (Moll) endarterectomy completed with a spiral stent to fix the lower “shelf”. On the whole, consensus was to favour angioplasty where possible for a limb salvage situation.
Femoropopliteal stenosis TASC C
Imaging options
Expert duplex colour ultrasonography is all that is required if it is available. CE CTA and CEMRA are there for confirmation. The consensus was that diagnostic arteriography is very seldom needed nowadays for profunda or femoropopliteal investigation but it remains the gold standard and is particularly helpful for tibial disease evaluations.
Vascular and endovascular options
The consensus was as TASC A and B lesions for intermittent claudication and in favour of balloon angioplasty for mandatory indications of critical ischaemia and incapacitating intermittent claudication. This is to avoid the poor healing from dirty ulceration and infected legs which carry into the wound. Surgery carries a mortality at 30 days of some 6% and the reports of the mortality from angioplasty are less than 1%. The evidence for stents is missing. Drug eluting stents and various coatings of stents have no proven added value.
Femoropopliteal stenosis TASC D
Imaging options
Expert duplex colour ultrasonography is all that is required if it is available. CE CTA and CEMRA are there for confirmation. The consensus was that diagnostic arteriography is very seldom needed nowadays for profunda or femoropopliteal investigation but it remains the gold standard and is particularly helpful for tibial disease evaluations.
Vascular and endovascular options
Intervention is only for limb salvage chronic limb ischaemia or critical ischaemia and incapacitating intermittent claudication. In other words the quality of life issue is the vital area that requires careful assessment. The patient’s needs are of paramount importance to evaluate. The consensus was for surgical bypass in this group. There is no evidence whether reverse vein or in situ vein are superior, but vein is better than prosthetics across the knee joint. The evidence favours the use of a vein cuff at the lower site if the knee is crossed by prosthetic. The commonest prosthetic use is PTFE. Patency rates of 80% at one year, 70% at two years are reported. Largely because of the impact of subintimal angioplasty, the consensus was that in future will this will become the domain of endovascular method also.
Femorotibial stenosis
Imaging options
Colour coded duplex scanning can be excellent in good hands but for smaller vessels, resolution is less good. Back up with CECT and CE MRA is recommend but IADSA remains the gold standard.
Vascular and endovascular options
On the whole, the consensus was against intervention for intermittent claudication but in the non-smoker some would intervene if the patient complained enough. Most patients would present with critical ischaemia with fear of limb loss. Endovascular is first choice by consensus, avoiding MRSA and wound infection. PTFE and prosthetics are avoided in infected legs. In situ vein bypass is favoured if angioplasty fails.
