Charing Cross goes from strength to strength

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More than 1,300 vascular specialist and industry professionals from 55 countries descended on the Imperial College, London for the 26th annual gathering. In addition to the main programme, a Vascular Imaging Course took place, supported by Philips Ultrasound and under the auspices of the Society for Vascular Technology of Great Britain and Ireland. The symposium also saw the CX Innovation Showcase make its debut, providing the chance for emerging vascular and endovascular companies to take center stage. The meeting featured product launches by W.L. Gore, Medtronic, Bolton Medical, GE Healthcare and Philips Ultrasound, and included six industry symposia.The Symposium was opened by Professor Roger Greenhalgh (Charing Cross Hospital, London), the Program Chairman and Meeting Founder. The opening session, chaired by Dr Ted Diethrich of the Arizona Heart Institute, Dr Marc Bosiers of AZ St-Blasius Hospital, Dendermonde, Belgium, presented preliminary results from the BEST-BTK (First-in-Man Experience with Biotronik absorbable metal stent below-the-knee), a dual center, prospective, non-randomised study analysing the safety and performance of the Lekton Mg (Biotronik) absorbable metal stents (AMS) in endovascular infrapopliteal procedures. AMS were implanted in 20 patients between December 2003 and January 2004 in the AZ St-Blasius Hospital and the Imelda Hospital. In 19 patients at one-month follow up limb salvage and primary patency were 100%. At three months, limb salvage was 6/6 and primary patency 5/6. Bosiers summarised the findings as: “In-human AMS implantation is safe, AMS provides sufficient support, AMS is absorbed as intended, AMS remains patent and better imaging with MR-angiography.”

Also at the symposium, Dr Iris Baumgartner of the Swiss Cardiovascular Center, Division Angiology University Hospital, Bern, Switzerland, looked at the non-coronary use of GPIIb/IIIa inhibitors. She presented data from the Evaluation of Percutaneous Transluminal Coronary Angioplasty to Improve Long-term Outcome with Abciximab Platelet Glycoprotein IIb/IIIa Blockade (EPILOG) trial, which showed the safety and efficacy of adjunctive abciximab in complex peripheral interventions. She then highlighted the ongoing ReoPro and peripheral arterial intervention to Improve clinical Outcome in patients with PAD (RIO Trial), which aims to show superiority of abciximab on a composite endpoint that accounts for mortality, amputation, repeat target vessel intervention, and target vessel occlusion at 30 days. 420 patients with chronic femoropopliteal occlusions; > 5cm are to be recruited, and recruitment is about half way through.Everolimus-eluting stents in the SFA was the subject of the talk given by Johannes Lammer of the department of interventional radiology, Medical University, Vienna, Austria. He showed the results of the FUTURE I and II trials. The coronary studies FUTURE I and II evaluated safety and performance of an everolimus eluting stent with a bioabsorbable polymer drug carrier and stainless steel stent platform. Results from the FUTURE I and II clinical trials demonstrated safety and efficacy. There was a profound effect in preventing in-stent restenosis (binary angiographic restenosis), with no restenosis at six-month follow-up among patients receiving an everolimus eluting stent (0/46) and an 87% reduction of in-stent late loss compared to a metallic stent control. In addition, Lammer highlighted Guidant’s DYNALINK stent, which has been shown to resist; radial compression, axial compression and bending.

Dr Ken Ouriel, Chairman, Division of Surgery, The Cleveland Clinic Foundation, looked at alfimeprase, which is a novel acting thrombolytic. Alfimeprase is a modified recombinant form of the direct fibrinolytic agent fibrolase, a metalloproteinase originating from venom of the southern copperhead snake. Unlike other thrombolytic agents that act by catalysing the formation of plasmin from its precursor plasminogen, alfimeprase directly cleaves the alpha and beta chains of cross-linked fibrin. While the thrombolytic efficiency of the traditional plasminogen activators has been linked to the plasminogen content within the thrombus, this limitation is not shared by alfimeprase. Alfimeprase is not fibrin-specific; it will degrade both fibrinogen and fibrin. Of potentially great importance, however, circulating alpha-2 macroglobulin (a2M) rapidly inactivates alfimeprase though an irreversible, covalent binding. This complex is rapidly cleared by the liver. As long as the amount of circulating alfimeprase does not exceed the threshold a2M, the potential for inducing fibrinogenolysis or distant fibrinolysis remains low. This has now been verified in early clinical results of the agent. Ouriel said that by virtue of these properties, catheter-directed administration of alfimeprase holds the potential to achieve rapid clot dissolution without the risk of distant hemorrhagic complications that has been characteristic of the traditional plasminogen activators. According to Ouriel, a comparison of the safety and efficacy of multiple doses of alfimeprase in acute PAO patients (a Phase II trial) began in mid-2004.

Kim Hodgson, Professor and Chairman Division of Vascular Surgery, Southern Illinois University, told the audience combination thrombolysis for peripheral arterial (PA) and venous thrombosis (VT) has the potential to restore flow more quickly and with reduced risk of systemic bleeding complications than the prolonged thrombolytic infusions of the past. Furthermore, these same characteristics may permit the endoluminal treatment of patients with relative contraindications to standard lytic infusions, including those at risk for serious systemic bleeding and those with critical limb ischemia for whom a more prompt restoration of flow is required. Hodgson continued by saying that unfortunately, all reports to date have been uncontrolled, non-randomised, and non-standardised with regard to device and lytic agent used, vessels treated, and, as well, as to lytic dosages and device protocols followed. Considering the innumerable variables involved, an absolute scientific answer as to the best combination therapy protocol for various VTs may never be determined, said Hodgson. “As such, it may very well be that the best we can expect for the foreseeable future is to have both mechanical devices and pharmacologic agents in our endovascular toolboxes to be used at physician discretion, customised to clinical circumstances and guided by individual experience,” concluded Hodgson.

Dr Roy Greenberg of the Cleveland Clinic Foundation tackled the subject of fenestration techniques for endovascular grafting. According to Greenberg, the fenestrated endovascular devices allow for the treatment of compromised proximal neck anatomy. Although tortuosity within the aneurysm neck remains a challenge by impeding the rotational ability critical for proper orientation of a fenestrated device, short necks (3-10mm in length) with a segment of infrarenal aorta that allow a seal to be created may be optimally managed with this technique. There are several factors, however, that must be overcome before the procedure becomes commonplace, said Greenberg. Device design is reliant upon proper pre-operative imaging techniques and the interpretation of such studies. Strategic planning of the procedure will ensure enough coverage of the visceral segment to achieve a seal while not over-complicating the procedure, and incorporating unnecessary branches. Success with the implantation procedure itself is dependent upon a thorough understanding of conventional endovascular aneurysm repair, as well as the management of visceral vessel disease. Finally, Greenberg emphasised that similar to most forms of endovascular aneurysm repair, there is little long-term data to ensure the durability of the repair.

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