A 62-year-old, right-handed man is evaluated for an episode of left leg weakness that spontaneously resolved within 30 minutes of onset. The patient also has had transient vision loss in the right eye. Medical history is significant for hypertension and diabetes mellitus. Evaluation reveals an atherosclerotic plaque in the extracranial portion of the supplying artery. During percutaneous stenting of the lesion, the vascular catheter is inserted into the right common femoral artery and gradually advanced to the level of the aortic arch. Which of the following is the most likely path of the catheter before stenting of the culprit lesion can be performed?
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This patient is having transient episodes of focal neurologic impairment, concerning for transient ischemic attacks (TIA), which often occur due to emboli originating from atherosclerotic plaques. The internal carotid artery supplies blood to the cerebral hemispheres, including the motor cortex, which controls the contralateral limbs. However, the ophthalmic artery, which gives rise to the retinal artery, originates from the ipsilateral internal carotid artery. Therefore, the combination of left leg weakness and vision loss in the right eye (amaurosis fugax) suggests a lesion in the right internal carotid artery.
Because TIAs are a risk factor for future stroke, intervention is warranted. After cannulation of the femoral artery, the catheter is advanced through the aorta. From there, the catheter can access much of the cerebrovascular circulation. The left common carotid and subclavian arteries branch directly from the aortic arch. However, on the right, the brachiocephalic (innominate) artery branches from the aortic arch then divides into the right subclavian and right common carotid. The common carotid then divides into the external carotid, which supplies blood to the face and neck, and the internal carotid, which supplies blood to the brain.
(Choice A) This is the path to the right external carotid artery. However, the external carotid artery supplies blood to the face and neck, not to the brain or retina.
(Choices C and D) The left common carotid artery branches directly from the aortic arch, then divides into the left internal and external carotid arteries. However, this patient's left leg weakness and vision loss in the right eye suggest a lesion in the right internal carotid artery.
(Choice E) This is the correct path to access the vertebral arteries, which supply the upper spinal cord, brainstem, cerebellum, and posterior part of the brain, rather than the motor cortex and the eye, which are affected in this patient.
Educational objective:
Transient ischemic attacks resulting in left leg weakness and vision loss in the right eye are likely due to emboli originating from the right internal carotid artery. The brachiocephalic artery branches from the aortic arch, then divides into the right subclavian and right common carotid arteries. The left common carotid and left subclavian arteries branch directly from the aortic arch.