Crawford classification

The Crawford classification is a system used to classify thoracoabdominal aneurysms and has important therapeutic implications. Precise classification of anatomical features allows accurate stratification of risk and appropriate operative planning ^1,2. 

Classification

The system divides thoracoabdominal aneurysms into five types ^1,3,4:

• type I: involvement of the entire descending thoracic aorta distal to the left subclavian artery, involving only the upper abdominal aorta superior to the renal arteries (25%)
• type II: involvement of the entire descending thoracic aorta distal to the left subclavian artery and most if not the entire abdominal aorta (30%)
• type III: involvementinvolvement of the descending aorta from the sixth intercostal space to include the renal arteries and most if not the entire abdominal aorta (<25%) 
• type IV: involvement of the entire abdominal aorta with sparing of the thoracic aorta (<25%) 
• type V: involvement of the descending aortafrom the sixth intercostal space to just superior to the renal arteries 

History and etymology

The classification system was composed by the American cardiovascular surgeon, Ernest Crawford (1922-1992) and his colleagues in 1986 when it was recognised that there was a correlation between the extent of thoracoabdominal aneurysms and patient outcomes ³.

The vascular surgeon Hazim Safi and his colleagues later modified the classification in 1953, adding a type V ⁴.