The 301 Classification: A Proposed Modification to the Stanford Type B Aortic Dissection Classification for Thoracic Endovascular Aortic Repair Prognostication

The Application of Computed Tomography Angiography in Aortic Dissection

“…A dissection limited to the descending thoracic aorta is classified as type IIIa, and one also involving the abdominal aorta is classified as type IIIb [5] [14]. Some scholars have also proposed other classifications [14] [15] [16] [17], such as the "3N3V" classification for endovascular graft exclusion. Based on the 3N3V classification, the dynamic pathophysiological NxNyB classification, determined according to the difference in blood flow velocity between different regions of the aorta, has also been proposed [16].…”

The 301 Classification: Old School Meets New School

“…Because of this need, there is an opportunity to view these revered classification systems as "living and breathing" rather than static entities. One such classification system provided by Ge et al 5 in the current issue of Mayo Clinic Proceedings is thus a notable advance in this field. The spirit of this proposed classification system is rooted in understanding how the anatomy of the initial TBAD contributes to continued expansion of the descending aorta after endovascular repair.…”

“…While these challenges exist, procedural success at both sites can be readily achieved, but this does not completely erase the potential for further false lumen expansion. Ge et al 5 readily acknowledge that multiple other factors can contribute to this problem, including multiple fenestrations between the true and false lumen as well as naturally occurring arterial branches from the aorta itself. The ultimate result of these situations is retrograde filling and ongoing pressurization of the false lumen.…”

“…This report by Ge et al 5 is only an initial attempt to define anatomic subgroups a priori that can then aid in defining subsequent risk and patterns of ongoing flow in the false lumen after endovascular correction of TBADs. The ultimate goal and relevance is to arrive at a more uniform approach than is currently practiced.…”

“…6 The original DeBakey and Stanford classification systems have steadily served for over a half century to help us understand the complex pathology of aortic dissections and guide the even more complex approaches to treatment. The current 301 Classification introduced by Ge et al 5 takes this prior foundation of understanding and adds the impact of newer techniques that were simply not available during the prior era. While there may be hesitancy to "infringe" upon the hallowed ground of the original DeBakey and Stanford classification systems, it is imperative that our ability to anticipate and prognosticate as a result of newer technology supersede our long-valued traditions.…”