Management of Diminutive Right Intramural Vertebral Artery with Dominant Left Vertebral Artery

Clinical Significance

Vertebral artery dominance is a common finding that occurs more frequently on the left side than the right, and anatomical variations are more common in the vertebrobasilar circulation than in the carotid system, creating a functional dependence on the dominant (left) vertebral artery for posterior circulation perfusion 1, 3
Vertebral artery atherosclerosis accounts for approximately 20% of posterior circulation strokes, making this anatomical variant clinically relevant 2, 4

Annual stroke rates for symptomatic intracranial vertebral stenosis reach 8%, emphasizing the importance of the dominant vessel's patency 5, 4

Patients should be educated to recognize posterior circulation ischemia symptoms immediately, such as dizziness, vertigo, and imbalance, which indicate potential compromise of the dominant vessel 1, 6

Medical management following guidelines for carotid artery disease is the standard of care, as no randomized trial evidence supports prophylactic intervention for asymptomatic vertebral artery variants 2, 4
Antiplatelet therapy, such as aspirin or aspirin plus dipyridamole, can reduce recurrent vertebrobasilar strokes 4
Aggressive atherosclerotic risk factor modification, including hypertension control, statin therapy, diabetes management, and smoking cessation, is recommended 4
Serial noninvasive imaging with CTA or MRA is recommended to assess progression of atherosclerotic disease in the dominant left vertebral artery and exclude new lesions 5, 4

CTA or MRA is preferred over ultrasound for vertebral artery evaluation, with 94% sensitivity and 95% specificity versus 70% sensitivity for ultrasound 2, 3
Catheter-based angiography may be required before revascularization when noninvasive imaging is inadequate 2

Endovascular intervention carries significant risk, including 5.5% periprocedural neurological complications and 0.3% death risk, and lacks randomized trial evidence of superiority over medical management 1, 3
Intervention should be reserved for recurrent ischemic symptoms despite optimal medical therapy or progression to preocclusive severity 3