Frequency of Aortic Arch Variants in Patients with Large Vessel Stroke in the Anterior Circulation

Special Article - Ischemic Stroke

Austin J Cerebrovasc Dis & Stroke. 2017; 4(1): 1051.

Frequency of Aortic Arch Variants in Patients with Large Vessel Stroke in the Anterior Circulation

Feiz M¹*, Nikoubashman O¹*, Müller M¹, Schiefer J², Brockmann C¹, Reich A² and Wiesmann M¹

¹Department of Neuroradiology, RWTH Aachen University, Germany

²Department of Neurology, RWTH Aachen University, Germany

*Corresponding author: Omid Nikoubashman, Department of Neuroradiology, University Hospital, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany

Maryam Feiz, Department of Neuroradiology, University Hospital, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany

Received: November 21, 2016; Accepted: December 29, 2016; Published: January 02, 2017

Abstract

Background: The presence of aortic arch variants (AAV) may complicate catheterization and prolong procedure times during endovascular stroke treatment. Hence, it is of great importance to know the prevalence of such variants in stroke patients in order to anticipate possible difficulties during catheterization. As the prevalence of such variants in stroke patients has not been investigated yet, we assessed the prevalence of AAV in patients, who received acute endovascular stroke treatment for large vessel occlusion in the anterior circulation.

Methods: We retrospectively analyzed computed tomography angiograms of 248 patients with acute stroke in the anterior circulation, who received endovascular stroke treatment, for the prevalence of a bovine arch, a direct origin of the left vertebral artery, and an aberrant right subclavian artery. We then compared the prevalence of AAV in our stroke cohort with a control cohort of 808 patients.

Results: AAV were found in 152 of all 1056 (14.4%) patients. There were AAV in 40/248 (16.1%) patients in the stroke group and 112/808 (13.9%) patients in the control group (p=0.374). The prevalence of AAV in the stroke and control cohort was as follows: bovine arch: 8.9% (22/248) versus 8.3% (67/808) (p=0.774); direct origin of the left vertebral artery from the aortic arch: 7.3% (18/248) versus 4.6% (37/808) (p=0.097); aberrant right subclavian artery: 0.8% (2/248) versus 1.2% (10/808) (p=0.742).

Conclusion: The prevalence of aortic arch variants in patients with stroke in the anterior circulation is comparable to the prevalence in cohorts without stroke.

Keywords: Stroke; Angiography; Thrombectomy; Aortic arch; CT angiography

Introduction

Endovascular stroke treatment has become a common treatment technique for acute ischaemic stroke when caused by large vessel occlusion (LVO) [1-5]. Prospective randomized trials showed that endovascular treatment is associated with favorable functional outcome (modified Rankin scale, mRS≤2 at day 90) in up to 60% of cases [1]. Khatri, et al. identified rapid recanalization as one of the major keys to favorable functional outcome [6]. It has been shown that endovascular access to the occlusion site can be achieved within minutes via inguinal puncture and catheterization of the aortic arch in the majority of cases [7]. Sometimes, however, catheterization of the aortic arch can be very time-consuming or may even prove to be impossible, hereby affecting clinical outcome [7-13]. Ribo, et al. suggested that the presence of aortic arch variants (AAV) such as the bovine arch might prolong procedure times in endovascular stroke treatment [7]. In order to anticipate possible difficulties during catheterization, it is of great importance to know the prevalence of such variants in stroke patients. Satti, et al. hypothesized that anomalous origins of the arteries of the brain might lead to altered haemodynamics [14]. Hence, it is conceivable that anatomical variants might predispose patients to the formation of atherosclerosis, which might in turn increase the risk for stroke. This would again result in a higher prevalence of AAV in stroke patients. However, to the best of our knowledge, the prevalence of such variants in stroke patients has not been investigated yet. We therefore aimed to compare the prevalence of AAV in patients, who received endovascular treatment for acute ischaemic stroke in the anterior circulation, with a control group of patients without stroke.

Materials and Methods

Patients

After obtaining ethical approval from our local ethics board, we retrospectively searched our prospectively maintained stroke registry for all patients with acute ischaemic stroke, who received endovascular stroke treatment between February 2010 and January 2015. We identified 374 patients who fulfilled these criteria. We excluded all 55 patients with stroke in the posterior circulation from our analysis. We also excluded 71 of the remaining 319 patients, for whom no computed tomography angiography (CTA) was available, or in whom CTA data did not allow evaluation of the aortic arch due to incomplete image acquisition or imaging artifacts. This left 248 patients, who received endovascular treatment for acute ischaemic stroke in the anterior circulation, to be included in our study. The control group was extracted from a previously published dataset [15]. For this aim, we searched for patients without a history of stroke. We identified 808 patients under the age of 60 years, who were all included in this study. We assessed the prevalence of AAV as well as age and sex in all 1056 patients. Stroke aetiology in stroke patients was classified according to the TOAST (Trial of ORG 10172 in Acute Stroke Treatment) classification [16]. Two radiologists, who were blinded to each other’s results, analyzed the cohorts independently.

Definitions

We assessed the prevalence of aortic arch variants, specifically a bovine arch, a direct origin of the left vertebral artery from the aortic arch, and an aberrant right subclavian artery (Figure 1). A bovine arch was defined as the clear origin of the left common carotid artery (CCA) from the brachiocephalic artery, whereas a common trunk of the left CCA and the brachiocephalic artery were not considered as bovine archs [17].