Stent-Graft Repair of Thoracic Aortic Diseases: A New Frontier in Endovascular Therapy

The FDA announced approval of the first thoracic endograft device (Gore TAG) on March 23, 2005. It signaled the true beginning of a new era in endovascular therapy, and the unmistakable 'message' that thoracic aortic surgery is about to be transformed in a dramatic and irreversible fashion. Thoracic aortic diseases, such as aneurysms, dissection, and others, share in common several important features - a relatively high incidence and high lethal potential, among others! Open surgical repair has been the acknowledged standard of care for decades, but it is far from ideal because of continuing severe morbidity and high mortality - in spite of the significant advances in surgical techniques and peri-operative care that have been achieved over the past 20 years. In other words, a very significant opportunity for innovative less invasive approaches and new technologies. While treatment of abdominal aortic aneurysms (AAA) was the main reason for development of stent-graft devices in the late 80's and early 90's, application of similar technologies for repair of the thoracic aorta gradually emerged as a very appealing use of such devices. Unlike with the AAA scenario where conventional surgery produces satisfactory results, for most low-risk patients optimal expertise is available in many, if not most, metropolitan and even rural areas in this country, the situation with thoracic aortic pathologies is quite different. Surgical repair is accompanied by very significant morbidity and mortality, even in the best hands, and the requisite large-volume experience and excellent outcomes are only available in relatively few centers of excellence across the country. This explains the rapidly growing excitement surrounding development of stent-graft devices and endovascular interventions for less-invasive repair of thoracic aortic aneurysms, dissections and related diseases. It represents, truly, a new frontier in endovascular therapy. And this is especially significant when one considers that the potential pool of patients for such therapies may come close to the magnitude of the AAA “market”: 50,000 procedures/year!¹

While devices development and technical approaches and understanding overall have advanced significantly over the past 10 years, this field remains in its infancy. Once these technologies achieve their full potential, it can be anticipated that stent-graft repair will become the predominant tool in the treatment of thoracic aortic pathologies, with significant patient benefit derived from the avoidance of open surgery-related major morbidity and mortality. But not unlike AAA repair, however, patients do need to remain under close surveillance for life - with imaging follow-up performed at annual intervals at a minimum. Thoracic endograft technologies are advancing rapidly at this time. FDA approval of at least two additional stent-graft devices is expected in 2006. Several others will be tested in clinical trials over the next few years. In the end, endovascular 'conquest' of the thoracic aorta is all but inevitable, relegating - once again! - conventional surgery to a stand-by or secondary role.

Correspondence: frank.criado@medstar.net