Association of Variant Aortic Arch Anatomy with Aortic Dissections and Thoracic Aortic Aneurysms
Jacob B Watson1, Jacob Siahan2, Charles Miller1, Harleen Sandhu1, Kristofer Charlton-Ouw2
1McGovern Medical School, Houston, TX;2HCA Houston Healthcare, Gulf Coast Division, Houston, TX
INTRODUCTION: The aortic arch is the main supply of blood to the head, neck, and upper limbs. Variations in conventional arch anatomy may complicate surgery if not accounted for accordingly. Previous studies identified some but not all aortic arch variants that are associated with dissection and aneurysm. This study aims to fill the gap in the literature of the relationship between arch variants and type A aortic dissections (TAAD), type B aortic dissections (TBAD), and thoracic aortic aneurysms (TAA). METHODS: We retrospectively reviewed computed tomography of patients with the following thoracic aortic diseases: TAAD (between 01/2007 to 03/2017), TBAD (between 01/2009 to 11/2016), and TAA (01/2009 to 12/2016). Arch variants were defined as: common origin of the innominate and left common carotid artery (bovine arch), isolated arch-origin left vertebral artery, aberrant right subclavian artery, and right-sided aortic arch. Other variants were identified but were rare and not included. Patient groups were compared with variant arches and analyzed by the χ2 test. RESULTS: We identified 904 patients, 595 with aortic dissection and 309 with aneurysm (Table 1). Most had normal anatomy, but aortic arch anomalies were common. There was a named variant for 38% of dissection patients and 34% of aneurysm patients. There were no significant differences between dissection and aneurysm patients with regards to bovine arch (p=0.97) and aberrant right subclavian artery (p=0.89) anatomy. There were significantly more TAAD and TBAD patients with isolated arch-origin left vertebral artery than TAA patients (p = 0.02). CONCLUSIONS: Isolated arch-origin left vertebral arteries were significantly more common in aortic dissection patients than in aneurysm patients. Patients with aortic arch anomalies comprise a significant portion of the population, and although they are often asymptomatic, they are associated with different aortic pathologies. Because of the increased possibility of encountering an isolated arch-origin left vertebral artery in dissection patients, greater awareness is advised when planning thoracic aortic procedures.
| Anatomy | TAAD or TBAD | TAA | Total Anatomy | p-value |
| Normal Arch Anatomy | 370 | 205 | 575 | - |
| Bovine Arch | 181 | 92 | 273 | 0.967 |
| Isolated Left Vertebral Artery | 36 | 8 | 44 | 0.020 |
| Aberrant Right Subclavian Artery | 7 | 4 | 11 | 0.894 |
| Right Sided Aortic Arch | 1 | 0 | 1 | - |
| Total Patients | 595 | 309 | 904 | - |
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