Date of Award
2026
Keywords
type B aortic dissection, thoracic endovascular aortic repair, bovine arch
Document Type
Thesis - ECU Access Only
Publisher
Edith Cowan University
Degree Name
Doctor of Philosophy
School
School of Medical and Health Sciences
First Supervisor
Wei Wang
Abstract
The bovine arch, an aortic arch variant characterized by a shared origin of the brachiocephalic artery and left common carotid artery, is frequently observed in type B aortic dissection (TBAD) patients. This anatomical configuration alters arch geometry and regional blood flow patterns, with potential implications for proximal landing strategies in thoracic endovascular aortic repair (TEVAR). Whether this variant represents a distinct anatomical risk that necessitates individualized landing strategies for TEVAR remains uncertain. In addition, the evidence regarding the epidemiological profile of the bovine arch in TBAD and its clinical implications in endovascular management is still limited.
This thesis comprises five chapters: a general introduction and aims of the thesis (Chapter 1); three results chapters (Chapters 2, 3, and 4); and a final chapter with a general discussion of the main findings, future directions, and conclusions (Chapter 5).
Chapter 1 outlines the clinical background of TBAD and TEVAR, reviews the definition and clinical relevance of the bovine arch, identifies the knowledge gaps, proposes research hypotheses, and put forward the aims of this thesis. Chapter 2 integrates an institutional radiological study with a systematic review and meta-analysis to evaluate the prevalence and clinical relevance of the bovine arch in TBAD. The findings demonstrate that the bovine arch is common among TBAD patients and exhibits regional variations in prevalence. Although a potential association between the bovine arch and adverse outcomes has been reported, the available evidence remains heterogeneous and limited, particularly regarding its impact on proximal landing strategies and postoperative prognosis following TEVAR. Chapter 3 presents a multicenter retrospective cohort study of acute TBAD patients undergoing TEVAR. Clinical characteristics, procedural features, and outcomes are compared between patients with a bovine arch and those with a conventional arch. Baseline anatomical features and landing zone selection are comparable between groups, as are perioperative outcomes and long-term mortality. However, the bovine arch is associated with an increased risk of proximal seal–related events (PSEs) and proximal reintervention, particularly among patients undergoing zone 3 landing TEVAR, whereas no increased risk is observed with zone 2 landing. These findings provide clinical evidence that proximal landing strategies should not be a uniformed approach and that bovine arch anatomy warrants individualized strategies for TEVAR. Chapter 4 describes a computational fluid dynamics study that investigates the hemodynamic mechanisms underlying the increased risk of proximal seal–related events in TBAD patients with a bovine arch following TEVAR. Patient-specific postoperative aortic models are used to simulate blood flow in the proximal landing zone. The analyses reveal elevated wall shear stress (WSS) in patients with a bovine arch, particularly with zone 3 endograft deployment, despite similar static pressure and velocity magnitude. These results provide mechanistic evidence linking bovine arch anatomy to PSEs and further support the need for tailored proximal landing strategies in this subgroup. Chapter 5 synthesizes the main findings and contributions, discusses clinical implications, and outlines limitations, future research directions, and conclusions.
In summary, the bovine arch is common in TBAD patients but remains under recognized in routine clinical practice, where a uniform proximal landing strategy has been widely adopted. This thesis demonstrates that zone 3 landing TEVAR in TBAD patients with a bovine arch is associated with increased WSS in the proximal landing zone and a higher risk of PSEs. Accordingly, a tailored endovascular strategy is warranted for this anatomical subgroup. Zone 2 landing TEVAR may be a potentially beneficial strategy for these patients, especially when zone 3 landing is associated with inadequate proximal sealing length. If zone 3 landing TEVAR is chosen after thorough evaluation, a closer postoperative surveillance is strongly advised for such patients.
Access Note
Access to this thesis is embargoed until 2nd July 2029
Recommended Citation
Ying, P. (2026). Clinical implications of bovine arch in thoracic endovascular aortic repair for type B aortic dissection. Edith Cowan University. https://doi.org/10.25958/w99a-3d98