Clinical significance of reversal of flow in the vertebral artery identified on cerebrovascular duplex ultrasound

Abstract

BackgroundReversal of flow in the vertebral artery (RFVA) is an uncommon finding on cerebrovascular duplex ultrasound examination. The clinical significance of RFVA and the natural history of patients presenting with it are poorly understood. Our objective was to better characterize the symptoms and outcomes of patients presenting with RFVA. MethodsA retrospective review was performed of all cerebrovascular duplex ultrasound studies performed at our institution between January 2010 and January 2016 (N = 2927 patients). Individuals with RFVA in one or both vertebral arteries were included in the analysis. ResultsSeventy-four patients (74/2927 patients [2.5%]) with RFVA were identified. Half of the patients were male. Mean age at the time of the first ultrasound study demonstrating RFVA was 71 years (range, 27-92 years); 78% of patients had hypertension, 28% were diabetic, and 66% were current or former smokers. Indications for the ultrasound examination were as follows: 44% screening/asymptomatic, 7% anterior circulation symptoms, 20% posterior circulation symptoms, 28% follow-up studies after cerebrovascular intervention, and 5% upper extremity symptoms. At the time of the initial ultrasound examination, 21 patients (28%) had evidence of a prior carotid intervention (carotid endarterectomy or carotid stenting), 21 patients had evidence of moderate (50%-79%) carotid artery stenosis (CAS) in at least one carotid artery, and 12 patients (16%) had evidence of severe (>80%) CAS. Of the 15 patients presenting with posterior circulation symptoms, 11 (73%) had evidence of concomitant CAS. In contrast, 22 of the 59 patients (37%) without posterior circulation symptoms had duplex ultrasound findings of CAS (P = .01). The mean duration of follow-up was 28 ± 22 months. Follow-up data were available for 63 patients (85%), including the 15 patients who presented with posterior circulation symptoms. Of these 15 patients, 5 underwent subclavian artery revascularization, including balloon angioplasty and stenting in 4 patients and open/hybrid revascularization in 1 patient. Five individuals were awaiting intervention. Three patients underwent carotid endarterectomy for CAS, with resultant improvement in posterior circulation symptoms. Finally, one patient was deemed too high risk for intervention, and one patient was found to have an alternative cause for symptoms. The remaining 59 patients continued to be asymptomatic during follow-up. One patient progressed to vertebral artery occlusion, and six patients had progression of CAS. ConclusionsSymptomatic RFVA responds well to intervention, including subclavian artery stenting and carotid intervention in patients with CAS. The majority of patients with this finding are asymptomatic at the time of presentation. Although progression of vertebral artery disease is rare, these patients may benefit from monitoring for progression of CAS with surveillance ultrasound.