The CX Great Debate saw Peter Taylor, London, UK, and Richard Gibbs, Imperial College, London, UK, persuaded 71% of the audience at the Charing Cross International Symposium yesterday to vote for their position against the motion “For uncomplicated type B dissections, early intervention is indicated”.

Their opponents in the debate, Christoph Nienaber, Rostock, Germany, and Jan Brunkwall, Köln, Germany, had the support of 29% of the audience. Audience discussion at the end of the session identified a need for a larger randomised trial with long-term follow-up that had clinically meaningful endpoints.

Nienaber and Brunkwall set out to persuade the audience that placing a stent graft early was important in order to heal the aorta. “Rupture, malperfusion, hypertension and down the line, aneurysm formation are some of the risks of type B dissection,” Brunkwall said.

Nienaber made the point that scaffolding was the only way to stabilise the progression of the dissection as data available so far showed that the disease is characterised by a downhill evolution over time. “If there is no scaffold, and the aorta is not remodelled, you are confronted with ongoing attrition rate in terms of cardiovascular death and progression of the disease. This is beneficial for even in so called stable or clinically silent patients,” he said. He made his views clear that no dissection was ever uncomplicated.

“Only pre-emptive stenting will ensure long-term remodelling and stability. Only remodelling stabilises the aorta and no drug that induces remodelling, only the likelihood of rupture, so supportive scaffolding should be offered to any type B dissection,” Nienaber said.

“What do we achieve with TEVAR in the setting of type B acute dissections? Fewer later interventions and lower mortality after five years,” Brunkwall said. The five-year long-term follow-up of the INSTEAD XL showed a statistically significant reduction in aorta-specific mortality and a statistically significant reduction in disease progression in favour of the combined TEVAR plus medical therapy arm.

Brunkwall also made the point that the ADSORB trial with false lumen thrombosis as an endpoint, had shown that patients receiving TEVAR have significantly more complete and partial thrombosis than the ones getting best medical therapy.

The ADSORB trial was a prospective randomised trial to compare TEVAR with best medical therapy in patients with acute uncomplicated type B aortic dissection. At the follow-up for one year, there was no death stroke or paraplegia in either group at 30 days and aortic remodelling at one year favoured the intervention but it did not reach statistical significance.

Taylor and Gibbs based their arguments around the fact that medical treatment is getting better. Briggs noted that a recent study (Fattori et al. J Am Coll Cardiol 2013;61:1661-78) had shown that survival at five years without intervention is 70–89%. They also highlighted the fact that TEVAR carries risks including retrograde dissection; stroke (3%); paraplegia (2.5%) and other complications. The team stated that all current endografts used in dissection are designed for use in aneurysms.

“There is no adequate evidence to recommend early intervention in all but a few patients with uncomplicated type B dissection. Only a small subgroup at high risk of aortic expansion will benefit from early intervention and these patients can be identified using techniques such as functional imaging,” Briggs said

Taylor also attacked the quality of evidence from randomised controlled trials that supported early intervention. “The ADSORB trial had only 61 patients in total. It was underpowered and stopped at one year and was therefore too short and small to answer questions about survival and efficacy. The INSTEAD trial had only 140 patients in total and underpowered for survival. In total, there have been only 201 dissection patients ever randomised,” he said.

Taylor made the point that drug therapy was getting better and that the available evidence showed that the majority of patients are alive with medical treatment; there is 80% survival at five years and that therefore, medical treatment was safe for the majority of patients with uncomplicated type B dissection. They do not need early intervention and there is an early mortality associated with TEVAR that cannot be ignored, he said.

A member of the audience noted that in order to make a clinical difference, all-cause mortality has to be the only endpoint at five years and the trial should be designed to show superiority. Martin Bjorck, Uppsala, Sweden, also commented on the difficulty faced in every day clinical practice. “There is a problem because we know from the data from the two randomised trials that it is rather safe to do TEVAR, but that there is a 3–5% risk of  very serious neurological complications that cannot be discounted. We know from the long-term results of the INSTEAD trial that if you do not treat, you have many patients developing dilatations and needing treatment later on that is more complicated. We need a larger randomised trial with long-term follow-up.”

CX voting results

Earlier in the session, 65% of the CX audience had voted that registry data is now irrelevant and that it was time that randomised trial evidence for TEVAR dissection became available. Nearly 80% also believed that aortic intervention for acute dissection should only be performed in recognised vascular centres with cardiothoracic surgery on site.

Michael Dake, Stanford, USA, outlined the first experiences with the Gore TAG (W L Gore) thoracic branch endoprosthesis and Frank R Arko, Charlotte, USA, presented on the MONA LSA (Medtronic) branched device results at a session yesterday. Both speakers shared early cases and their results.

Thoracic aortic aneurysms that involve the left subclavian artery often leave physicians no choice but to use surgical techniques or to cover the branch vessel. “Although reports from single-centre experience with the hybrid approach have been positive, a single branch thoracic endograft specifically designed for treatment of the aortic arch (Zone 0–2) could be useful in extending the advantages of endovascular repair to the aortic arch.  As such, the Gore TAG Thoracic Branch Endoprosthesis is designed as a modular system which allows for treatment of aortic arch pathologies using a less invasive hybrid endovascular approach,” Dake said.

He presented on the Zone 2 US investigational device exemption feasibility trial that will enrol 20 to 40 patients at six sites. Patients will be followed for five years. The study will evaluate the device for the treatment zone 2 aneurysms.

The Gore TAG thoracic branch endoprosthesis has a modular construction design with off-the-shelf components. It has an inner lumen for anchoring and sealing the branch component. The complete system consists of aortic and branch components designed for the use in the arch, and also the accompanying accessory devices to facilitate delivery.

“The system is easy to use with a single femoral access and requires minimal catheter manoeuvres. It is safe with zero ischaemic time and has low risk of branch vessel coverage. After the first four cases, successful access and deployment of the endoprosthesis was seen in all cases. There was one procedural type 1 endoleak that resolved without re-intervention at one month. There were no device-related endoleaks, but one type 2 endoleak was seen at one month. There were no deaths or neurological events. There were no site reported serious adverse events related to the device,” he said.

Dake explained that the procedure to deploy the device included inserting the guidewires in aorta and branch vessel; introducing the aortic component over both guidewires into position within the arch; deploying aortic component and withdrawing catheter; advancing the introducer sheath and dilator and advancing and deploying branch component.

In order to be enrolled, patients had to have descending thoracic aortic aneurysms requiring placement of the proximal extent of the aortic stent graft in Zone 2. The primary endpoints of the study were: successful access and deployment of the thoracic branched endograft and the primary patency of the side branch assessed by angiography when the procedure finishes. The secondary endpoints included a one-month core lab analysis, assessing the side branch primary patency and device-related endoleaks.

Arko told delegates that there was a clinical need for left subclavian artery preservation in association with encroaching thoracic artery aneurysm. He presented the current status of an early feasibility trial in the FDA’s new innovation pathway testing the Valiant Mona LSA device.

The key goals of the trial are to validate the procedure in humans; assess the safety and performance acutely and at 30 days and collect imaging data to augment the current understanding.

Arko told delegates that the Valiant Mona LSA Thoracic Stent Graft consisted of a flexible cuff “volcano” on the main body. The system is a two-graft system and the main graft system comes in diameters between 30 and 46mm and in the single length of 15cm. It is a two-wire system as well and the secondary wire can be snared and then the second branch is brought up and deployed. The branch graft itself is made of a nitinol helical wire and polyester fabric. It has a proximal flare. The branch graft is always 40mm in length and a 15F profile, femoral access system.

The early feasibility trial is a prospective, non-randomised, three-centre, premarket clinical study that has enrolled nine patients. The primary safety and effectiveness objectives were measured acutely and at 30 days. “The follow-up schedule will be at 0-30 days, six months, 12 months and annually through five years,” Arko said.

The principal investigators are Eric E Roselli, Cleveland, USA, Frank R Arko, Charlotte, USA and Matt Thompson, London, UK.

Arko revealed that the current status of the early feasibility trial had seven patients enrolled as part of the US cohort and two enrolled as part of the cohort outside the US. One emergent case had been enrolled in the USA, outside of trial. Acute procedure results from all seven patients revealed 100% technical success and 100% patency in both main and branch stent graft. There were no type I or III endoleaks.

“All current devices need a healthy landing zone to seal. To achieve sufficient landing zone, the left subclavian artery may be sacrificed with resulting complications, such as 6% arm ischaemia, 4% spinal cord ischaemia, 2% vertebrobasilar ischaemia, 5% anterior circulation stroke and 6% death. Left subclavian artery preservation is recommended in the literature. 17–43% of patients undergoing TEVAR have planned coverage of the left subclavian artery to achieve an adequate proximal seal and the coverage of the left subclavian artery without revascularisation is the single most important predictor of post-TEVAR stroke,” Arko said.

At the ilegx Collaboration Day, attendees learnt about the best management therapies for diabetic foot care and vascular reconstruction in critical limb ischaemia patients and for the second year running, the symposium broadcast edited live cases treating superficial femoral artery lesions to the Far East and North America in an event named Endovascular Electronic Education, sponsored by Abbott Vascular.

In the morning, three edited live cases were showcased to the Far East. The first case was performed by Andrej Schmidt in Leipzig, Germany, the second procedure was carried out by Peter Goverde in Antwerp, Belgium, and the third case was performed by Josef Tacke in Passau, Germany. The Abbott Supera stent system was used to treat occlusion and total occlusion of the superficial femoral artery and proximal popliteal artery.

Schmidt, Goverde and Tacke were present to answer questions from the audience at CX and those watching the live broadcast in the Far East.

Responding to questions about how a physician chooses a stent, Schmidt said: “In some cases it is clear—if it is a calcified lesion, for me it is clear that a drug-eluting balloon might not be so good, we know this from our data, and the Supera stent is the stent of choice.” He added that more data are required to make the stent selection process more comprehensive.

In the afternoon, edited live cases were broadcast to North America.

Early referral, fast track care and multidisciplinary work: key approach to save limbs

The ilegx initiative, launched in 2008, was created in response to the increasing number of lower limb amputations which are mostly due to type II diabetes. Michael Edmonds (London, UK) who is one of the founders of ilegx, introduced the “diabetic foot care” session, which was organised in conjunction with the King’s College Hospital Open Access System, with a presentation which highlighted the importance of early diabetic foot referral and interdisciplinary work as an effective approach to reduce the number of lower limb amputations, flagship principles of the ilegx initiative. He said: “Up until recently, the diabetic ischaemic foot has defeated every health care system in the world. However, a strategy which combines early referral and interdisciplinary working has led to improvements in care.” With this in mind, he commented, “ulcers can now be healed and amputations can be prevented.”

Edmonds also referred to the importance of organising a “fast-track” service in a “one-stop” visit, comprising clinical assessment, same-day investigations and urgent management to treat infection and revascularise the foot, when dealing with cases of “diabetic foot attack.” “This is best carried out in a diabetic foot clinic which can see the ischaemic patient in an open access system without delay and has rapid availability of debridement and intravenous antibiotics to treat infection and control the septic vasculitis.” He also said that diabetic foot patients who experience repeated crises from the rapid onset of infection need a special form of such easily accessible care provided by the diabetic foot clinic. “Such integrated fast track care can rapidly restore the circulation, limit tissue necrosis, save the limb from amputation and provide complete recovery from the foot attack,” he commented.

An interdisciplinary team including podiatrists, nurses, orthotists, microbiologists, interventional radiologists and surgeons—including vascular surgeons, orthopaedic surgeons and plastic surgeons—is the ideal team required in the management of diabetic foot, Edmonds noted.

He also mentioned that to complete an effective management of diabetic foot, follow-up and rehabilitation are required.

Interdisciplinary views on diabetic foot care

A vascular surgeon, an interventional radiologist and a podiatrist from King’s College Hospital, London, UK, shared with CX delegates their best practices treating diabetic foot.

Vascular surgeon Hisham Rashid, said that “the incidence of type II diabetes mellitus is increasing across the world with an expected rise in 2030 to more than 12% in a large population of the world.”
This is a worrying figure taking into account that “a major amputation rate is significantly higher in diabetic patients,” he noted.

Rashid told CX delegates that aggressive revascularisation with angioplasty, bypass or hybrid techniques is essential for limb salvage and reduction of major amputation rate. He mentioned that at King’s College Hospital, 77% of cases are treated with angioplasty and 23% with distal bypass. He said that distal bypass surgery “plays a major role in revascularisation, especially in patients presenting with significant tissue loss and when angioplasty is not feasible.” Hybrid techniques in “no-option” critical leg ischaemia have also proven very effective in preventing major amputation in this challenging group of patients, he commented.

 
At King’s, Rashid noted, revascularisation using distal and ultra-distal bypass has a very good outcome with a one-year amputation rate of 3.4% and 30-days mortality rate of 1.5–1.7%. At one-year, “mortality is significantly influenced by end-stage renal failure and age rather than diabetes mellitus,” he said.

Interventional radiologist Dean Huang, said that the concept of “foot attack” and “time is tissue” in diabetic patients means that treatment of an infected ulcer should be handled as an emergency with the management of a multidisciplinary team. At King’s College Hospital, “we follow this approach; we work on the basis of rapid access to diagnosis, rapid access to intervention and follow-up of interventional and surgical procedures.” From the interventional radiologist perspective, he said, “rapid access to imaging diagnostics enables the selection and planning of the optimal strategy.” Ultrasound, CTA and MRA have their place and angiography remains the gold standard, he commented. “Prompt definitive treatment with radiological intervention and/or surgical bypass to revascularisation for healing in conjunction with wound care and antibiotics is the key to achieve prevention of amputation,” Huang noted. “The threshold of what can be treated with endovascular procedures is shifting as more sophisticated devices appear on the market.”

Podiatrist Jennifer Tremlet, spoke about the different techniques used at King’s College Hospital to heal diabetic foot wounds. “Diabetic foot patients are complex cases, they experience extensive tissue loss and infection. In order to achieve successful wound healing, they require intensive wound care and rigorous monitoring.” She said that, depending on the complexity of the wound and the type of patient, they use different multi-modal techniques including debridement, larvae therapy, hydrosurgery therapy topical negative pressure therapy, split skin grafts and pressure relief. 

Foot care and arterial reconstruction

At a session on foot care and arterial reconstruction, Christopher Attinger (Washington, USA) said that using the angiosome principle to guide revascularisation is a critical component for optimising wound healing. He explained that the angiosome concept divides anatomic regions into three-dimensional blocks of tissue fed by source arteries and creates a framework for understanding tissue perfusion, predicting wound healing, and planning surgical interventions. Therefore, “understanding the boundaries of an angiosome and the vascular connections between source arteries provides the basis for limb salvage to optimise revascularisation to ischaemic areas and promote wound healing.”

Mauro Gargiulo (Bologna, Italy) spoke on the need to have multidisciplinary guidelines to support the treatment of critical limb ischaemia. He referred to a consensus document that has been recently published on the treatment of peripheral arterial disease in diabetes written by the Italian Societies of Diabetes (SID, AMD), Radiology (SIRM) and Vascular Endovascular Surgery (SICVE). The consensus, published in Nutrition, Metabolism & Cardiovascular Disease (Aiello A et al, 2014; 24: 355–369), higlights that “the prevalence of peripheral arterial disease is high in diabetic patients and, associated or not with peripheral neuropathy, can be found in 50% of cases of diabetic foot.” Gargiulo said that the document summarises indications for revascularisation, revascularisation techniques and details on follow-up of revascularised patients, among other topics.

In the same session, Bijan Modarai spoke about effective cell therapies for revascularisation of critical limb ischaemia and Roberto Ferraresi discussed patient-centric revascularisation strategies.

At the end of the ilegx Collaboration Day a roundtable consensus on the role of drug-eluting balloons for the treatment of superficial femoral artery including data from the IN.PACT SFA, ILLUMINATE, Levant 2 and BIOLUX-PI studies was held. Vascular News will be reporting on the outcomes of this discussion.