3.0 Epidemiology

According to several studies, the incidence of non-A non-B aortic dissection is lower than type A aortic dissection but is higher than type B dissection (Gawinecka, Schönrath and von Eckardstein, 2017; Lempel et al. , 2014). The frequency of non-A non-B dissection among all acute aortic dissection patients has been shown to vary from 3%-11% (Rylski et al. , 2017; Sievers et al. , 2020; Lempel et al. , 2014; Urbanski and Wagner, 2016) (Table 1).
INSERT TABLE 1
Studies by Sievers et al. as well as Lempel et al. showcased that non-A and non-B dissection patients tend to be younger and have a lower mortality compared to type A dissection patients (Lempel et al. , 2014; Sievers et al. , 2020). The median age for non-A non-B dissection patients was 59 years compared to 65 and 67 years for type A and type B dissection respectively (Sievers et al. , 2020). A study by Rylski et al. divided non-A non-B dissection into descending-entry and arch-entry types with similar frequencies recorded in both types (Rylski et al. , 2017). However, a prospective study by Urbanski et al. revealed a higher case load in descending-entry type patients. This study also showed that surgery improved the outcomes of these patients compared to a more conservative approach. A multicentre study using the International Registry of Acute Aortic Dissection also reported that over 16% of type B aortic dissection cases had extension of the dissection into the aortic arch (Nauta et al. , 2016).