2.5. TEVAR Reintervention 
Recent studies have estimated the need for reintervention at 5% of those undergoing TEVAR for un-TBAD [14, 21, 53, 60]. The indications for late re-intervention are varied (Table 4). Specifically, Qin et al. [12] defined adverse events requiring re-intervention as a total thoracic aortic diameter enlargement > 60 mm, RTAD, rupture, ulcer-like projection, SINE or persistent endoleak with enlargement. Similarly, Nienaber et al. [16] identified other indications such as an enlarging total aortic diameter over 55 mm or malperfusion.
It seems endoleaks, aortic expansion and SINE are the most commonly reported indications for re-intervention [12, 21, 28]. Reintervention within 1-year was more likely to be indicated in acute un-TBAD patients when compared to interventions performed in the subacute phase. Matched analysis, showed the acute TBAD re-intervention rates were significantly higher (P= 0.007) [7].
A large retrospective cohort study showed that the re-intervention rate following TEVAR for un-TBAD is (41/751; 5.46%) [21]. Thoracic stent grafting has a lower reintervention rate when compared to other treatment modalities and a meta-analysis by Li et al. [22] revealed a significant difference in late re-intervention (OR = 0.33; 95% CI: 0.13-0.85). This meta-analysis also showed that TEVAR is associated with a significantly reduced rate of re-intervention, late rupture (OR = 0.21; 95%CI: 0.10-0.43), and aneurysmal dilatation/expansion (OR = 0.15; 95% CI: 0.04-0.63) during follow-up
Should “Uncomplicated” TBAD really exist?
A significant number of un-TBAD patients on OMT alone, may require further complex intervention with TEVAR due to progression of the dissection. Currently, only un-TBAD patients who meet certain criteria making them “high-risk” for aorta-related complications without immediate risk of rupture or malperfusion are offered pre-emptive TEVAR [4]. These high-risk criteria are an initial aortic diameter of >40mm, an entry tear >10mm, an associated FL diameter of >22mm, and a free-floating TL [5, 61]. Although it is worth noting that these criteria vary slightly in different international guidelines with no uniformity for intervention. Despite not exhibiting evidence of rupture or malperfusion this raises the question whether or not it is correct to categorise these patients as un-TBAD. In addition, given both co-TBAD and un-TBAD have identical underlying pathology, also given that pre-emptive TEVAR for un-TBAD has proven its safety and effectiveness, is it wise to continue using the complications-based classification system?
Conclusion
The introduction of TEVAR for un-TBAD has shifted the paradigm of clinical practice. Thoracic stent grafting has proven to be a safe and effective treatment modality for un-TBAD by providing favourable mid- and long-term survival outcomes, including complications, and aortic remodelling. Overall, it can be concluded that with further research, pre-emptive TEVAR could be considered first-line treatment in all un-TBAD patients rather than just those classed as high-risk.