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).