Ann Thorac Surg 2005;79:794-795
© 2005 The Society of Thoracic Surgeons
INVITED COMMENTARY
Marc R. Moon, MD
Division of Cardiothoracic Surgery, Center for Diseases of the Thoracic Aorta, Washington University School of Medicine, 3108 Queeny Tower, 1 Barnes-Jewish Plaza, St Louis, MO 63110
(E-mail: moonm{at}msnotes.wustl.edu).
Hsu and colleagues from Taiwan report their 8-year experience treating 107 patients with acute type B aortic dissections. Overall, the authors’ results are excellent and consistent with those published in other large series. However, like any retrospective study, there are obvious difficulties in comparing different treatment regimens. For example, I find the authors’ reporting of 99% 1-year survival for medically treated patients versus 75% for surgically treated patients (16 of 107) somewhat misleading. At first glance, one may conclude that medical therapy is superior; however, the only patients who underwent surgical intervention were those with life-threatening complications. In reality, the intent-to-treat was medical in all patients, with a failure rate for this strategy of 15%. Furthermore, deaths that occurred in the surgical group were not necessarily a consequence of the surgery itself, but rather a consequence of the complexity of the dissection that prompted the need for surgical intervention. Thus, a more appropriate title may simply have been "Outcome of Medical Treatment in Patients with Acute Type B Aortic Dissection," since this study does not address the impact of a proactive surgical approach for patients with uncomplicated dissections. Patients with life-threatening complications are not the subgroup of most interest; obviously, surgical intervention, whether open or closed, must be performed in these patients as a lifesaving measure. Rather, it is the patients with uncomplicated dissections that will present a quandary when endovascular treatment alternatives become widely available in the near future.
It is conceptually appealing to consider aortic repair to eliminate the intimal tear and obliterate the false lumen to diminish the risk of late aneurysm formation in acute type B dissections, but historically, technical challenges in reconstructing the descending aorta near the arch have made early, elective open surgical repair an unattractive option in most cases. With advances in endovascular stent-graft technology, we should soon have the opportunity to consider a "less-invasive" approach. I eagerly await the arrival of thoracic stent-grafts for off-the-shelf use, but I am also apprehensive because these new endovascular techniques will not be without complication; if we are not careful, their application to acute dissections may become widespread before they have been investigated appropriately. We must resist the temptation to perform endovascular reconstruction of the aorta merely "because we can"—instead, we must first prove that it is the "right thing to do." In the current series, Hsu and colleagues reported a near perfect 99% 5-year survival rate for patients with uncomplicated dissections. This makes it imperative to have a mortality rate that approaches 1% with an endovascular approach before we consider elective stent-grafting for patients who would otherwise do quite well with medical therapy alone. Hsu and colleagues have set the bar very high, and I think we truly have our work cut out for us to present a convincing case for a proactive surgical approach.
Randomized, prospective trials are rare in our literature, especially when it relates to new technology that has the potential for significant commercial gain, but I strongly believe that endovascular techniques will permit, for the first time, a controlled trial comparing aggressive medical therapy versus early surgical treatment of uncomplicated type B aortic dissections. To this end, it is imperative for us to reinforce to our medical colleagues the need for surgical consultation in all cases of acute aortic dissection to best avoid exploitation of this new technology in the catheterization laboratory before it has been proven to benefit patients with survival rates that favorably compare to those presented in the current report.
Related Article
-
Outcome of Medical and Surgical Treatment in Patients With Acute Type B Aortic Dissection
- Ron-Bin Hsu, Yi-Lwun Ho, Robert J. Chen, Shoei-Shen Wang, Fang-Yue Lin, and Shu-Hsun Chu
Ann. Thorac. Surg. 2005 79: 790-794.
[Abstract]
[Full Text]
[PDF]
