Thoracic challenges: dissection and aneurysms

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Each year in Europe, an estimated 50,000 patients are diagnosed with lesions of the thoracic aorta, including those caused by Type B dissections. Many of these patients also have serious co-morbidities such as coronary artery disease, emphysema, high blood pressure or diabetes. These conditions make it difficult, if not impossible, for them to survive open surgical repair, which has been the standard of care. For those patients, considered ineligible for open surgical repair, conservative anti-hypertensive medical management, or ‘watchful waiting,’ is often used as a treatment option.

Chronic Type B aortic dissection

One of the many highlights at this year’s CX Symposium will be the analysis of the Investigation of Stent-grafts in patients with chronic Type B Aortic Dissection (INSTEAD) trial. This was a prospective, multi-centre, randomised, controlled, clinical trial that compared the one-year outcome of Type B dissection treated with thoracic stent-graft and conventional antihypertensive vs. conventional antihypertensive treatment. Professor Christoph A Nienaber, Rostock University, Germany, and principle investigator of the trial, will analyse the trial, determine how this course of treatment compares to conventional treatment and outline the significance of the results in terms of treatment options for patients presenting with Type B dissections.

Acute Type B aortic dissection

Moreover, Professor Jan Brunkwall, University of Cologne, Germany, will present an overview of the Acute Dissection Stent-grafting OR Best Medical Treatment (ADSORB) study, which is investigating the mortality and re-intervention rate of dissection related diseases. The study will enrol 250 patients with acute (<14 days) Type B dissection (visual ischaemia or rupture) in 30 European centres and will utilise the GORE TAG Thoracic Endoprosthesis. “The medical treatment of acute Type B dissection are not without complications and patients still die with this treatment. The purpose of the study was to investigate the mortality and the re-intervention rate due to dissection related disease (aneurysms in particular),” Brunkwall told Vascular News. “This study is important because there is now a use of stent grafts in acute dissections, but [previously] we had no scientific proof with efficacy. There is a high mortality still in the best medical treatment group even though it’s slower than with open-surgery it is still high, rating from 10-30% within one year,” Brunkwall stated. He explained that this is the first study really examining acute dissection and not chronic ones. Other studies such as the INSTEAD, investigate the chronic type so the inclusion criteria is after 14 days and up to one year. Patient enrollment began in January 2007 and will be completed within one year. There will be interim results after another year, and a three year follow-up. The final results are expected to be published in five years. “There is actually no randomised trials on this issue and our primary goal of course is to see the effect of stent grafts, [and our] secondary goal is that we could get a good database,” concluded Brunkwall. Thoracic aneurysms

In addition to thoracic dissection, there will also be a special session reporting the latest clinical data from the three thoracic aneurysm trials. Dr Jon Matsumura, Chicago, IL, will report the initial results from the STARZ-TX2 clinical trial (Study of Thoracic Aortic Aneurysm [TAA] Repair with the Zenith TX2 Thoracic TAA Endovascular Graft), sponsored by Cook Medical. This will be the first time the results have been reported in Europe.

The STARZ-TX2 trial, which enrolled more than 200 patients at 39 clinical sites around the world, studied the safety and effectiveness the Zenith TX2 for the treatment of thoracic aortic aneurysms. The primary hypothesis for effectiveness is that patients treated with the Zenith TX2 TAA will have equivalent 30-day rupture-free survival compared to the surgical control. A secondary hypothesis is subjects treated with the Zenith TX2 TAA will have equivalent or fewer complications compared to the surgical control group through 30 days following implant. All patients enrolled in the STARZ-TX2 trial are being evaluated at regular intervals during the 12 months following either insertion of the Zenith TX2 or open surgery.

In addition, Dr Ron Fairman, University of Pennsylvania, will present the results from the VALOR (Medtronic Ave Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms) trial (high-risk and test arm) as well as outline the design for the VALOR II trial. The objective of VALOR is to evaluate the safety and efficacy of the Talent system for patients with thoracic aortic disease who were high risk for open surgery and/or non-surgical candidates. The proximal and distal aortic non-aneurysmal neck diameter requirement was within the range of 18-42mm. The study was a prospective, non-randomised, multi-centre, consecutive, observational trial with a safety primary endpoint of all cause mortality. The efficacy primary endpoint was the proportion of patients with successful aneurysm treatment.

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