Letter by Modarai et al Regarding Article, “Contemporary Analysis of Descending Thoracic and Thoracoabdominal Aneurysm Repair”
To the Editor:
We read with interest the article by Greenberg et al,1 published in the August 19, 2008, issue of Circulation. In our opinion, however, there were several problems with the classification of aneurysms as described in the article.
The classification of thoracoabdominal aneurysms used in this article (Table 1) differs significantly from the original classification by Crawford et al2 in important ways, yet the authors state that “the Crawford classification was used to categorize the aortic disease”:
The type I aneurysm includes a repair extending to below the diaphragm but not necessarily involving the visceral vessels. This would be classified by the Crawford classification as a descending thoracic aneurysm, which carries a more favorable prognosis. The diaphragm is a poor landmark on which to base any classification.
A type II thoracoabdominal aneurysm may have a normal segment of infrarenal aorta. In Crawford’s classification, the aorta in a type II aneurysm is affected to the bifurcation of the aorta. The type II aneurysm in the present classification may therefore equate with a Crawford type I aneurysm.
A type IV aneurysm does not necessarily include the visceral vessels. This would be the equivalent of a juxtarenal or a suprarenal aneurysm, which is not part of Crawford’s classification.
This article is therefore comparing apples with oranges, and these disparities favor endovascular over open surgery and could bias the results against open surgery.