Ann Thorac Surg 2002;74:765-766
© 2002 The Society of Thoracic Surgeons
Invited commentary
Thoralf M. Sundta
a Division of Cardiovascular Surgery, The Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
e-mail: sundt.thoralf{at}mayo.edu
Despite a successful repair of the ascending aorta and, in some cases, aortic arch, most patients with DeBakey type I dissection are left with a chronic and potentially lethal disease that demands long-term follow-up and threatens future surgery. Within 5 years of the acute event, aneurysmal dilatation of the descending thoracic aorta will bring 20% of patients to an operation that carries significant risk of mortality and morbidity even in the most experienced hands. Accordingly, efforts to reduce the risk of aneurysmal expansion of the remaining aorta are of importance to patients and physicians. The authors of this study have explored the application of endovascular stent technology at the time of the first operation for acute dissection, with the aim of accomplishing this goal.
A persistent false lumen can be expected in 60% to 80% of patients undergoing traditional repairs, despite attempts to resect the entry site. Superior survival and freedom from reoperation are associated with thrombosis of the false lumen. The authors hope to promote thrombosis of the false lumen by stent implantation, thereby reducing the risk of late aneurysmal expansion.
Two questions must be asked of the data: First, were the authors successful in promoting thrombosis of the false lumen? Unfortunately, of seven patients in whom the stent was successfully deployed, only 2 (28%) had "complete" thrombosis of the false lumen. While "partial thrombosis" was seen in an additional four, this must be far short of what the authors had hoped for. The second question—and an equally important one—is have the investigators done any harm? Repair of acute dissection already carries an operative risk of 10%–20%. If the authors propose to add to the complexity of the procedure, particularly for an essentially prophylactic purpose, surely it must be accomplished at negligible incremental risk. Fortunately, none of their patients suffered perforation of the thoracic aorta and none had postoperative paraplegia, a complication that should be rare with instrumentation of the upper thoracic aorta but one of such profound impact that it cannot be taken for granted. Equally, one must be concerned about malperfusion syndromes involving other vascular beds. And what of the late risks of infection of the prosthesis? If the strategy is unsuccessful and the aorta expands, will late reoperation be complicated by the presence of flotsam and jetsam just distal to the subclavian artery?
We are indebted to the authors for having the courage to explore this new technology. At this point, however, the results are far too tentative and follow-up far to brief to recommend that others enter the fray. Study of this technology should remain in controlled settings with careful follow-up while we await the answers to these questions.
