Stress Trans Cranial Doppler in Diagnosis of Cerebral Hypoperfusion and Treatment in a Patient with Isolated Vertebral Perfusion
Christopher E. Yi, MD, Jasmeet Singh, MD, John Bennett, PhD, Nitin Garg, MBBS, MPH.
Wake Forest School of Medicine, Winston-Salem, NC, USA.
Chronic global cerebral hypoperfusion syndrome from extracranial cerebrovascular obstruction is a rare debilitating disease. Treatment options are limited and extracranial to intracranial bypasses are seldom performed. Revascularization of a dominant vertebral artery may help improve collateral perfusion but is high risk due to peri-procedure ischemia. In this case report, we describe a patient with global hypoperfusion symptoms, whose cerebral inflow consists only of a critically stenotic, anomalous right vertebral artery that originated from the right common carotid in presence of an aberrant right subclavian artery.
A 66 year old male presented with severe recurrent episodes of presyncopy and dizziness, progressively worse over the past year. He had previous prior bilateral carotid endarterectomies that occluded. CT angiogram of the head and neck was obtained, which confirmed bilateral ICA occlusions, left vertebral artery occlusion, an anomalous right vertebral artery originating from the proximal right common carotid artery with a high grade stenosis at the ostium (Figure 1A), and an aberrant right subclavian artery with a diminutive right vertebral artery that joined the anomalous right vertebral artery at the distal V2 segment (Figure 1B). Selective cerebral arteriogram, confirmed a >60% stenosis at the origin of the anomalous right vertebral artery with post-stenotic dilatation. Cerebrovascular reserve was determined with transcranial doppler ultrasound (TCD) evaluation of the bilateral middle cerebral artery velocities during inhalation of CO2 mixtures. Preoperatively, this patient showed borderline cerebrovascular reserve on the left, and no reserve on the right.
The patient was taken to the operating room for a right vertebral to common carotid artery transposition (Figure 1C). A right axillary to right vertebral artery shunt was performed to maintain cerebral perfusion to reduce the time of cerebral flow disruption. Continuous TCD monitoring was utilized as an adjunct for cerebral perfusion monitoring. Test clamping of the anomalous right vertebral artery prior to shunting showed a >50% decrease in MCA flow on TCD, which resolved immediately after shunting (Figure 1D).
The patient was successfully treated with a right vertebral to common carotid artery transposition, with complete resolution of symptoms and significant improvement in cerebral flow on follow up TCD.
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