CX NEWS

Attendees at the CX Innovation Showcase learnt about the latest branched devices for endovascular aneurysm repair yesterday. New technologies for the vascular and endovascular treatment of lower limb, venous and carotid disease and arteriovenous access were also discussed. Stephen Greenhalgh (London, UK) and Andrew Holden (Auckland, New Zealand) were the chairmen of the session.

Greenhalgh told CX Daily News that the objective of this year’s session was “to get an idea of the pipeline of the major companies to tackle branched endovascular aneurysm repair.” 

Among the branched devices featured at the CX Innovation Showcase, Michel Makaroun, Pittsburg, USA, presented on the investigational TAG thoracic branched endograft from Gore. He said that the design of this off-the-shelf device started “nearly a decade ago”.

The device has been built upon existing aortic and peripheral platforms and can be adapted to many anatomies. It is easy to use, requiring only femoral access and minimal manipulations, and is safe with minimal risk of branch coverage, he noted. The device has an aortic component which incorporates an internal portal allowing seal and fixation of the side branch component. The device diameters are between 21 and 53mm and the aortic treatment ranges between 16 and 48mm. “We have very early clinical experience with the device and it has been positive so far,” he concluded.

Zenith T-Branch and P-Branch endovascular grafts

Timothy Resch, Malmo, Sweden, spoke about Cook Medical’s Zenith T Branch and P Branch endovascular grafts, which are off-the-shelf systems for complex aortic repair. These devices, Resch noted, are aimed to “eliminate complex planning as well as manufacturing delays in the treatment of aortic aneurysms”.

The Zenith T Branch, designed to treat thoracoabdominal aortic aneurysms, has been CE-marked since 2012. Resch explained that the system consists of two main components that are compatible with the existing Zenith Thoracic Endovascular Aortic Repair (TEVAR) and iliac limbs components for proximal and distal extension depending on the aneurysm extent. The first component is a standard multi-branched device aimed at preserving flow into the main visceral side branches of the aorta. The second component is a “unibody” bifurcated device that comes in five different total lengths to match the individual anatomy. “Planning is simplified by using a predesigned planning sheet where the extent of the aneurysm as well as position of the target vessel ostia are marked,” he noted.

Resch highlighted that clinical and anatomical studies have determined that the applicability of the device in the treatment of thoracoabdominal aortic aneurysm ranges from 70 to 80% of the cases and multicentre studies are ongoing to evaluate further the applicability and efficacy of the device.

Resch went on to present the Zenith P Branch endovascular graft. He said that this device is designed to treat juxtarenal and suprarenal aneurysms as well as short neck infrarenal aneurysms which are not suitable for standard infrarenal EVAR. “As with the T Branch system, the P branch has two main components and is compatible distally with standard Zenith iliac limb extensions,” he said. In contrast to the T Branch, the P Branch it consists of a main body including two fenestrations for the renal artery and one for the superior mesenteric artery as well as a scallop fenestration for the coeliac trunk. Planning is done in a standardised fashion using a planning sheet and a template outlining the device.

Resch told delegates that anatomical studies in patients with juxtarenal abdominal aortic aneurysm have estimated the applicability of the P Branch to 50–70% but clinical data are still lacking. The device is not commercially available and international, multicentre feasibility studies are ongoing.

Relay branched endograft

In a subsequent presentation, Toru Kuratani, Osaka, Japan, talked about early and midterm results with the Relay branched endograft from Bolton Medical. He told delegates that he has been using the device, which is comprised of a flexible main body and two internal tunnels inside the main body, since 2013.

Early results in 12 patients treated with the Relay endograft have shown positive outcomes with 100% procedural success rate, no endoleaks, stroke or major complications, Kuratani noted. At six months and 12 months, there was a 100% survival rate and 100% freedom from aortic events. He said that endovascular repair with this device “may become a wonderful option for high risk patients.”

Martin Funovics (Vienna, Austria) presented a new branched endograft from Jotec. He told delegates: “If off-the-shelf technology fails, this is where the new technology from Jotec might jump in.” The device is adaptable to variable design choices and the branches are flexible with easy cannulation, he noted. He reported that the initial results were also promising.

The Nellix sealing system was featured at the Innovation showcase with presentations from Andrew Holden, Auckland, New Zealand, and Bob Mitchell, Hertogenbosch, The Netherlands. Mitchell told delegates that Nellix is a “game changer” in the treatment of abdominal aortic aneurysms. He said: “Nellix is not simply a next generation EVAR device, but it is rather a completely different approach to abdominal aortic aneurysm therapy. Nellix stands alone as the one and only alternative to EVAR.” This is a breakthrough concept designed to dramatically reduce known EVAR complications such as endoleaks, migration and reinterventions, he added.  

As a highlight in the latest carotid innovations, Sumaira Macdonald, Sunnyvale, USA, spoke on the Michi system (Silk Road Medical), a cervical access approach that is used to reduce the risk of microemboli in carotid stenting. Macdonald told the audience that early results with the device “are encouraging” and “may represent a paradigm shift in the management of carotid artery disease.”

In the lower limb session, Michael Orlowski presented data for the Legflow Paclitaxel-Eluting Peripheral Balloon Dilatation catheter from Cardionovum.

David Deaton, Washington, USA, spoke on the Rox device for endovascular arteriovenous fistula; and Steve Elias, Englewood, USA, presented data on Clarivein, an endovenous ablation system used in the treatment of varicose veins.

Concluding the session, Greenhalgh told CX Daily News that there is a clear call from the audience for more evidence and more data from the technologies showcased. However, he added: “It is wonderful to see the rich pipeline of new devices that are coming.” 

Physicians share new product ideas at “Speed Dating” event

For the first time at the Charing Cross Symposium, physicians shared their product ideas with experienced physician inventors, engineers and marketing experts in an event called “Speed Dating”. The event was held at the Innovation Showcase yesterday. Physician inventor David King (London, UK) won the “Dragons’ Den CX Innovation Showcase prize”.

Jean Bismuth, Elika Kashef and Stephen Greenhalgh, chairs of the session, designed the event to provide a platform for physicians who are seeking advice from experts on how to put their business and product ideas onto market. 

Bismuth explained the rationale for the event: “Many young physicians and even senior physicians—as they gain experience through the years—have a desire to design their own medical tools and they start thinking and developing the idea. Unfortunately, sometimes they cannot get their innovations onto the market because they do not have the access to the experts to take the idea to the next level. With this “speed dating” event, we want to collaborate to bridge that gap.”

At the event, physicians had the opportunity to speak first to a group of physicians who have experience developing devices, then to engineers and finally to marketing experts.

“Protect your idea” was the main advice that experts gave to the participants.

After the “Speed Dating” event, the Dragons’ Den CX Innovation session took place and awarded David King with £1,000 for his innovative idea. King designed a Doppler device called “Blue Dop” that works via a tablet device. He said that it uses a special algorithm that can measure blood pressure without the need to use a cuff or needles. He noted that the device is unique in the market and can be used in renal dialysis, arterial disease and sports medicine.

The first-ever presentation of 12-month data from the randomised multicentre IN.PACT SFA trial revealed that treatment with the IN.PACT Admiral drug-eluting balloon (Medtronic) was significantly superior to percutaneous transluminal angioplasty in terms of reinterventions and patency. The results were presented at the Charing Cross Symposium 2014 (5–8 April 2014, London, UK).  

The randomised controlled IN.PACT SFA trial results showed that clinically-driven target lesion revascularisation rates were significantly lower with the drug-eluting balloon as compared to those achieved with angioplasty (2.4% vs. 20.6%, p<0.001). Similarly, the primary patency rate achieved with IN.PACT Admiral was 82.2%, while the primary patency achieved with angioplasty was 52.45% (p<0.001). Primary patency at 360 days was also calculated by Kaplan-Meier survival estimates; at this specific time point, it was 89.8% for the drug-eluting balloon group and 66.8% for the angioplasty group.

According to Gunnar Tepe, Rosenheim, Germany, who presented the 12-month results of the trial, there is robust level 1 evidence to show that the IN.PACT Admiral drug-eluting balloon has achieved the lowest target lesion revascularisation and highest patency rates ever reported with an endovascular therapy in the superficial femoral artery.

An analysis of weighted average clinically-driven target lesion revascularisation rates at 12 months showed a lower reintervention rate with the Admiral drug-eluting balloon (2.4%) than with any other technology: 26.4% for percutaneous transluminal angioplasty, 14.3% for bare metal stents and 10.2% with drug-eluting stents.

“The results of this rigorously conducted randomised controlled trial warrant a review of current treatment guidelines for peripheral artery disease in the lower extremities,” said Tepe, who is the trial’s principal investigator. “In fact, they should lead to a reconsideration of how we treat patients with claudication, as the highest level of clinical evidence now distinguishes the IN.PACT Admiral drug-coated balloon as a primary therapy for atherosclerosis in the superficial femoral artery.”

The IN.PACT SFA trial enrolled 331 patients at 57 sites across Europe and the USA and patients were randomised to either receive treatment with a drug-eluting balloon or percutaneous transluminal angioplasty. To ensure data accuracy and reliability, patency endpoints underwent evaluation by an independent imaging core lab, while all clinical events were adjudicated by an independent clinical events committee. To prevent bias, both the imaging core lab and the clinical events committee were blinded to the patients’ randomisation.

The two cohorts were well-matched with regard to baseline patient demographics. Nearly all of the patients had moderate or severe claudication and approximately 5% suffered from rest pain because of more advanced disease. Other baseline characteristics including diabetes (40.5% vs. 48.6%) and hypertension (91.4% vs. 88.3%), as well as mean lesion length (8.94cm vs. 8.81cm) and percentage of total occlusions (25.8% vs. 19.5%) were also similar between the two groups.

The IN.PACT Admiral drug-coated balloon received the CE mark in 2009 but remains an investigational medical device in the United States, where it is under review by the FDA.

Audience recognises the impact of drug-eluting balloons 

Following the presentation of the IN.PACT SFA data, the voting results at the Charing Cross Symposium 2014 captured a powerful shift in audience perception regarding the value of drug-eluting balloons in peripheral arterial disease. While just two years ago, a poll identified that 27% viewed drug-eluting balloons as an alternative to stents, in 2014, 72% now do so.

Voting questions from previous years were presented again this year, in order to assess the clinical views of audience members with regard to drug-eluting balloons. The results then captured the data on the year-on-year shift in perception towards these devices, and indeed the phenomenon of drug elution itself. The audience response polls revealed that nearly 90% voted that drug-elution was worthwhile in the superficial femoral artery. Last year, just 57% cast their vote stating that drug-elution was worthwhile in this anatomical region.

Roger Greenhalgh, London, UK and chairman of the symposium, noted that the voting trends likely reflected the multidisciplinary nature of the meeting itself as the audience members and faculty are composed of the leading vascular surgeons, interventional radiologists and interventional cardiologists.

Two years ago, when delegates at Charing Cross 2012 were asked what the role for drug-eluting balloons was, 27% voted that they were an alternative to stents; 33% voted that they should be used for in-stent restenosis; 19% voted that they should be used as a last resort and 21% voted that they had no role. Now in 2014, 72% voted that drug-eluting balloons are an alternative to stents; 21% voted that they should be used for in-stent restenosis; 3% believed that they should be used as a last resort and 4% voted that they had no role at all.

There was a similar swing in opinion regarding the cost-effectiveness of drug-eluting balloons. In 2011, 75% of voters stated that they did not find drug elution cost-effective in the superficial femoral artery and only 25% voted that they did. Yet in 2014, 67% said, yes, drug elution is cost-effective in the superficial femoral artery and 33% said it was not.

The voting also revealed a sharp shift seen in favour of drug-eluting balloons from last year. In 2013, 57% of the delegates voted that drug elution was worthwhile in the superficial femoral artery, while 43% believed that it was not. In contrast, in 2014, an overwhelming 87% agreed with the proposition “drug elution is worthwhile in the superficial femoral artery” while 13% did not.

Andrew Holden, Auckland, New Zealand, presented data for on the developments in bioresorbable technology yesterday. He said that, as drug-eluting balloon data are limited to short and intermediate length lesions, bioresorbable stents or scaffolds are an “exciting prospect” for the future.

He said that the long and mobile femoropopliteal arterial segment is a challenging environment for endovascular intervention; for more complex lesions a scaffold is often required to prevent residual stenosis and flow-limiting dissection. An anti-restenosis strategy is also important, particularly in claudicants where long-term patency is vital, he noted.

“Drug-eluting balloons are highly promising but have only been studied for any duration in relatively short lesions. Drug-eluting stents have shown satisfactory patencies in intermediate length lesions but suffer the problems of a permanent self-expanding metallic implant.”

Addressing this problem with drug-eluting stents, Holden said for many years bioresorbable stents have been eagerly awaited in the superficial femoral artery.

“A bioresorbable stent may provide a scaffold to optimise the acute result after angioplasty without the long-term irritation of a self-expanding stent. Such a scaffold must withstand the hostile environment of the superficial femoral artery, provide mechanical support and integrity through vessel healing, remain biocompatible through resorption and facilitate drug delivery,” he said.

Three bioresorbable stents have recently been studied in the superficial femoral artery. The Abbott Esprit 1 trial used a balloon expandable PLLA scaffold in iliac and femoral arterial lesions ≤50mm in length that could be treated by a single 6.0mmx58mm device. The study reported excellent procedural success. Although lesion length was short (mean 35.7mm), the patency data and improvement in Rutherford-Becker status at one year was very encouraging, Holden said.

The 480 Biomedical Stanza stent has been studied in the STANCE trial. This flexible, self-expanding stent is a PLGA and bioreorbable elastomer composite and fully resorbs in 12–15 months, according to Holden. Acute performance and subsequent stent strut encapsulation and resorption has been evaluated with optical coherence tomography (OCT). This study reported excellent procedural success and acute stent performance, treating longer lesions (up to 90mm).

Holden explained that late lumen loss seen in the first cohort of patients was due to a combination of vessel recoil and neointimal hyperplasia. The device was modified in a second patient cohort with minimal vessel recoil. A paclitaxel, drug-eluting version of the scaffold has recently entered the clinic in the SPRINT trial, he added.

Holden also reported that the Igaki-Tamai bioresorbable scaffold (Igaki Medical Planning) has been used in the superficial femoral artery in a 30 patient cohort. Acute procedural results were very good, as in the STANCE trial.

“Binary restenosis rates at 12 months were unacceptably high and further modifications are planned. Small clinician initiated trials using coronary bioresorbable stents in the tibial arteries are being performed but meaningful results are not yet available,” Holden commented.

“There has been considerable progress with bioresorbable stents in the superficial femoral artery. The technology is not yet ready for routine clinical practice but that exciting prospect should not be far away,” Holden concluded.

In his technical report of the Hybrid Vascular Graft (Gore) for the reconstruction of the superficial femoral artery, Jean Bismuth (Houston, USA) said the graft allowed a rapid sutureless anastomosis and was highly versatile in complex situations.

Bismuth reported that the graft is the first device that has been designed to “address the ever expanding number of hybrid operations, which combine both endovascular and open surgical techniques.” He explained that it was an expanded PTFE vascular prosthesis that had a constrained nitinol section and added that it “greatly expanded” the treatment options for dialysis access, aortic debranching, and arterial bypass procedures. Bismuth commented: “The graft allows the surgeon to minimise the invasiveness of a procedure all the while benefiting from the advantages of a bypass.”

He explained that although initially the graft was launched for arteriovenous dialysis access, it now had the same indications as “any vascular graft”. For example, at his centre, where the graft has been used in 150 cases, it has been used for “a good proportion of iliofemoral bypasses and a bunch of visceral debranching as well.”

Bismuth commented: “In the femoropopliteal segment, the Hybrid graft permits access through a smaller incision to an artery which is either hard to reach behind the knee or is diseased. The nitinol reinforced segment of the graft can be introduced through a less invasive access and can take advantage of the stent to treat a stenotic segment.”

As well as reviewing the advantages of the graft, Bismuth also discussed the “pearls for success” with the device and these included the fact that “imaging was key” to successfully accessing patient anatomy—“you have to know what you are going into”, he noted. Another pearl was that correct sizing was “essential” as he said that the graft should not be oversized by more than 20%. Bismuth added that he never oversized by more than 1mm and that correct sizing could mean that sutures were not needed at all. He explained: “Gore recommends a couple of patching sutures, but I have never put any in. It is a personal choice and I have never had an issue with needing to use sutures. It is all about the sizing. If you only upsize by 1mm, you are probably not going to have any problems.” Other tips for success included not completely inserting the nitinol reinforced segment into the artery, ensuring adequate outflow and inflow, and covering all of the disease in the artery.

Bismuth concluded: “Hybrid procedures are likely to be more prevalent; the Hybrid graft allows a rapid sutureless anastomosis, particularly for difficult sites and rapid bailout. It is highly versatile in complex cases.” 

Andrew Bradbury (Birmingham, UK) reported that a new randomised controlled trial, BASIL 2, has been launched because there is an “urgent need” to undertake pragmatic, scientifically robust and publically-funded randomised controlled trials of endovascular interventions in patients with severe limb ischaemia.

Bradbury stated that the findings of BASIL 1, which showed a significant improvement in overall survival with endovascular therapy in patients with severe limb ischaemia compared with surgery at 7.3 months (but not at two years), and those of other studies have been used to justify “an endovascular approach” in this group of patients. However, he added that BASIL 1 may no longer be relevant because of several changes in the treatment of severe limb ischaemia since the study was published. For example, Bradbury reported, endovascular therapy had “changed beyond recognition”, interventional radiologists were more skilled at performing endovascular therapy, and surgeons could now perform hybrid procedures. Furthermore, other studies in this area were industry sponsored and had not produced the answers needed to make nation-wide decisions about which therapy to use. Bradbury said, during development of guidelines for peripheral artery disease, the UK’s National Institute for Health and Care Excellence (NICE) were “shocked” that the day-to-day decisions for the management of severe limb ischaemia were being based on such a “lack of evidence”. 

Therefore, the BASIL 2 has been launched to provide more data on the effects of endovascular therapy compared with surgery in patients with severe limb ischaemia. Bradbury reported that in the superiority trial, 600 patients with below-the-knee or femoropopliteal atherosclerosis will be randomised to receive “best endovascular therapy” or a vein graft. He added that the recruitment process, which was due to start in a few weeks, would last for 36 months and the primary endpoint was the rate of amputation-free survival at 33 months. To show superiority of endovascular treatment, Bradbury reported, there needs to be a 15% difference in the primary endpoint between the groups.

The study will be funded by the National Institute for Health Research and, according to Bradbury, has received “overwhelming support” from both interventional radiologists and vascular surgeons. He acknowledged that recruitment for BASIL 1 had been difficult—“it is the reason why my hair is grey; in fact, it is a wonder that I have any hair at all”—but said the vascular community were now more accepting of the need for randomised controlled trials.

Concluding, Bradbury said that there was an “urgent need” to undertake pragmatic, scientifically robust and publically-funded randomised controlled trial of endovascular therapies in severe limb ischaemia that were powered for clinically important endpoints and include a full cost-effectiveness analysis.” He added that the BASIL 2 would look at the health costs and, for “the first time”, the social costs of the interventions in the study. “Without data from such randomised controlled trials, we cannot be sure that endovascular interventions are not going to be associated with net harm or suboptimal use of precious health resources,” Bradbury said. 

In Leicester, UK, rapid-access surgery for symptomatic carotid stenosis has been offered since October 2008. Ross Naylor reviews the practical lessons that have been learned with the experience. He discussed this topic at CX35 on Tuesday.

By Ross Naylor

When the trials randomised “recently symptomatic” patients to carotid endarterectomy or medical therapy, symptoms had to have occurred

Consequently, there has been a move towards performing surgery as soon as possible after the index event (ie treating transient ischaemic attack on a par with unstable angina). NICE advise that patients should undergo surgery

Some surgical/interventional colleagues have not actively embraced the move towards expedited intervention. For them, patients benefit from a period of stabilisation and assessment (in order to reduce procedural risk), while others believe that intervening early is associated with an unacceptably high procedural risk that may negate any benefit conferred through early intervention. The reality is, however, that the surgeon who operates within two weeks with a 10% procedural risk is still likely to prevent more strokes (in the long term) than the surgeon who defers surgery for four weeks and then operates with a 0% risk!

The Leicester Unit has offered a rapid-access surgery service since October 2008. All patients are seen in a 24/7 cerebrovascular clinic and those with 50–99% stenoses are transferred to the Vascular Unit for expedited surgery. 400+ symptomatic patients have now been treated (12%

First; it is not unusual (in the hyper-acute setting) for the duplex operator to comment that there is a critical stenosis that does not appear to open out into a normal calibre vessel. In the past (when patients were randomised some time after the index event), this might have been diagnosed as “near occlusion” (little benefit from surgery), but this is not the case in the hyper-acute setting. The diagnostic “give-away” is that high velocities are maintained across the stenosis (even if the distal lumen cannot be visualised) and CT angiography almost always shows a reconstructable vessel. In “near occlusion”, there are very low systolic velicities and little or no diastolic flow. Accordingly, corroborative imaging is mandatory (in the hyper-acute period) before recommending against urgent carotid surgery.

Second; anyone setting up this kind of service better get used to seeing recurrent events in up to 15% of patients between admission and surgery (despite being on antiplatelet and statin therapy). Up to 40% of patients referred acutely will have spontaneous embolisation on transcranial Doppler. Recurrent events (prior to surgery) were rarely encountered in the past, largely because patients were not referred so quickly.

Third; patients undergoing surgery (using general anaesthetic) with a pre-existing neurological deficit will almost always suffer a transient worsening of their deficit postoperatively. In the past, this was an indication for re-exploration. The “key” to management is how quickly the patient recovers from anaesthesia. If it is relatively quick, they will return to their pre-operative neurological status within an hour or so. Accordingly, it is important to warn recovery staff who may otherwise be alarmed at the apparent neurological deterioration.

Fourth; be prepared to adopt even more obsessive attention to surgical technique. We have found that careless skin preparation can trigger embolisation and transcranial Doppler is invaluable in warning of the embolising (unstable) patient during carotid mobilisation.

Fifth; be prepared to encounter a higher prevalence of post-endarterectomy hypertension (25% in theatre recovery, 25% back on the ward). This is usually seen in patients with poorly controlled blood pressure pre-operatively and it is essential that medical/nursing staff have guidelines for managing this condition. If you are going to treat patients in the hyper-acute period, you cannot adopt an ad hoc approach to blood pressure management, as patients will be subject to a greater risk of hyperperfusion stroke or intracranial haemorrhage.

Finally; (and contrary to what has previously been expected), our experience of operating in the hyperacute period has not been associated with a significant increase in procedural risk.

However; if you still harbour doubts about the benefit of intervening in the hyperacute period, ask yourself how you would want to be treated should you suffer a transient ischaemic attack and have a significant carotid stenosis?

Thought so! Don’t your patients deserve the same?