Several studies have established the technical reliability and anatomical compatibility of the GORE cTAG endograft in patients who undergo TEVAR [8,9,10]. However, this study goes further by quantitatively assessing changes in the configuration of the native aortic arch pre- and post-deployment using defined anatomical landmarks across the spectrum of acute and chronic aortic pathologies, a method utilised seldom elsewhere in the literature [11], and correlating these with durability outcomes. A growing body of the literature supports the notion that poor stent apposition and stress at the graft–aorta interface may contribute to an increased risk of reintervention after TEVAR [12, 13]. This study specifically offers an objective evidence, correlating the degree of aortic arch stent-induced geometric change with complication and reintervention rates thereby suggesting a functional definition of conformability beyond target deployment accuracy alone.

Our findings demonstrate that 88% of patients had < 10% change in the proximal landing zone (PLZ) angle, and 79% a < 10% change in the overall aortic arch angle, indicating a high degree of conformability of the GORE cTAG stent to the native anatomy. Crucially, the small proportion of patients who experienced larger angular changes experienced significantly higher rates of reintervention with a type 1a endoleak representing the most common indication for reintervention. This supports our hypothesis that greater distortion of the native aortic arch following TEVAR correlates with a lower repair durability.

While current literature offers limited direct quantification of the link between stent graft conformability and clinical outcomes, existing data highlight the significance of proper device apposition and conserving native arch geometry. Böckler et al. [8] demonstrated high deployment accuracy and good arch apposition with the GORE cTAG stent graft across various challenging aortic arch anatomies. Moreover, earlier studies have stressed the need to minimise bird-beak formation to enhance procedural durability and lower device-related complications [14]. These findings collectively imply that less geometric distortion may lead to better arch apposition and, consequently, improved clinical results.

In the present study, the low incidence of bird beaking (10.8%) further supports the adaptability of the GORE cTAG to complex arch anatomy and aligns with previous reports of its conformability. Importantly, despite using a relatively low threshold for bird-beak definition (> 5 mm), only 2 of the 10 identified patients required reintervention. This observation is consistent with reports that the contemporary GORE cTAG device is associated with a lower incidence of bird-beak formation than earlier-generation devices, for which rates of approximately 44% have been described [6].

Bischoff et al. [15] also examined the early conformability of the GORE cTAG in TEVAR for type B aortic dissection, finding a high level of anatomical matching before and after the procedure, which aligns with our results. Although that study looked at geometric changes post-TEVAR, our analysis adds to this by using a reproducible measurement method with Endosize® software to quantify angular change. This approach provided a more objective evaluation of conformability and its connection to clinical outcomes.

In the current study, there was no notable difference in reintervention rates among different aortic arch types (p = 0.26), indicating that post-procedure results might depend more on the extent of geometric change caused by the intervention rather than the native arch classification. This aligns with the idea that changes in arch shape due to treatment—rather than the initial complexity of the arch—are more crucial for the long-term performance and durability of the device.

Bird-beak configuration after TEVAR is increasingly recognised as a clinically relevant radiological finding. Previous studies evaluating other thoracic stent graft platforms, including Captivia and Cook Zenith devices, have shown that arch anatomy influences bird-beak formation and that delayed bird beak may develop during follow-up. Bird-beak morphology and poor proximal conformity have also been implicated in device-related complications, including thoracic endograft collapse [16, 17]. These observations further underline the importance of post-implant arch geometry. However, direct evidence linking device-specific conformability to comparative long-term clinical outcomes and reintervention remains limited. As design evolution has occurred in other commercially available devices beyond Gore cTAG, further comparative studies are warranted to determine whether improved conformability is device-specific or reflects a broader advancement across contemporary endograft platforms. Moreover, although CT angiography is routinely used for post-procedural assessment, a universally standardised radiological method for evaluating bird-beak configuration and apposition has not been consistently adopted across studies.

Taken together, these findings suggest that minimising treatment-induced distortion of the aortic arch may be an important determinant of TEVAR durability. Nevertheless, these observations should be interpreted in the context of the retrospective design, potential confounding, and the absence of direct comparison with other devices. Prospective studies using standardised imaging assessment and comparative device evaluation are needed to confirm these findings.

Although aneurysmal disease accounted for the highest proportion of underlying pathology requiring reintervention (followed by dissection and trauma), the difference in the reintervention rate between aneurysmal disease and dissection did not reach statistical significance (p = 0.4). This challenges the suggestion that a compromised aortic wall or greater intrinsic instability alone predisposes to the need for reintervention through the increased likelihood of the aorta to redilate.

Instead, our findings support the alternative hypothesis that reintervention is more closely related to graft-induced change to the aortic configuration than to the underlying pathology itself. This view is reinforced by the lack of any significant association between underlying pathology and geometric aortic arch change following intervention; in fact, dissection accounted for a larger proportion of patients with > 10% of change in the aortic arch configuration, while aneurysm accounted for a larger proportion of the patients in which a > 10% change in PLZ was demonstrated. These findings are consistent with previous reports indicating that degenerative connective tissue disorders do not independently predict reintervention following aortic arch repair [18].

Overall survival rates in this study align well with those reported elsewhere in the literature. The overall 30-day survival rate in this study (94.5%) closely aligns with the 94.3% documented in a study conducted by Fankhauser et al. [19] and 92.5% in a study by Hu et al. [20]. Similarly, the longer-term survival rates in this study are well aligned to those elsewhere. Specifically, studies demonstrating pooled data for all-cause mortality across a range of aortic pathologies report survival rates of 73–93.7% and 43–77.7% at 1 and 5 years, respectively [21, 22], similar to the 86% and 80%, respectively, in this study.

Previous studies focused exclusively on aneurysmal disease have reported slightly lower survival rates with the study by Fankhauser et al. noting 76.4% and 52.9% survival at 1 and 5 years, respectively, and a further study by Salem et al. [23] reporting 76% and 59%. A dedicated 2008 analysis of the GORE TAG device demonstrated at 5 year survival of 68% [24]. Within our cohort, when patients with underlying aneurysmal disease were analysed separately (n = 17), the survival rates at 1 and 5 years were 82% and 50%, respectively, although the small sample size limits the strength of this analysis.

Although perhaps unexpected, the 5-year survival rate of acute patients was higher (88.8%) than that of chronic ones (71.4%). The likely explanation behind this is the relatively high number of young patients in this cohort, presenting with traumatic blunt injury. The 5-year survival in this cohort of patients (n = 24) is 100%. These patients rarely have comorbidities and, if they survive the initial trauma, are likely to have a much better survival outcome.

While the findings of this study are promising, the study is limited by the modest sample size. Future multicentre prospective studies are needed to determine whether these conformability metrics can be integrated into risk stratification models. The other limitation is the heterogeneous pathology in the studied cohort. Although disease progression can vary, potentially affecting long-term outcomes, device conformability remained consistent across the spectrum of pathology.