4.3 False Lumen
Based on the proven risk of complications and death associated with the position of the entry tear, FL position is also an important consideration alongside it’s diameter, configuration, and whether it is thrombosed. A FL diameter of 22mm at the upper descending thoracic aorta is a significant (p < 0.001) independent risk for aneurysmal change and subsequent death. Furthermore, it is able to predict late aneurysm formation with 100% sensitivity and 76% specificity (22), although some studies have found it to be an insignificant marker of mortality (Figure 3 ) (19). Further growth of the FL is more likely in cases where there are many patent FL segments, which are typically found in younger patients with longer segments of the dissected aorta (32). A patent FL inflicts hemodynamic stress onto the aortic wall, which is likely to cause progressive growth of the segment. False lumen patency is therefore widely accepted as an independent predictor of aortic growth (12-14, 17, 18), and there appear to be corroborating findings which suggest that aortic growth is reduced when the FL is completely thrombosed FL (14, 25). Partial thrombosis is predictive of aortic growth (21, 33) and post-discharge mortality (outlined earlier in the context of FDPs) (8).