Recurrent left internal carotid artery stenosis in a patient with intrathoracic carotid bifurcation and right aortic arch.

Intrathoracic carotid bifurcation (ITCB) is a rare vascular anomaly often associated with Klippel-Feil syndrome (KFS); however, its coexistence with tetralogy of Fallot (TOF) has not been previously reported. A male patient in his 30s with childhood TOF repair presented with mild right-sided hemiparesis and motor aphasia due to an ischemic infarction. Cerebral angiography revealed ITCB at the T2 level with severe left internal carotid artery stenosis, a right aortic arch, and aberrant left subclavian artery. Percutaneous transluminal angioplasty initially resolved the stenosis, but progressive restenosis required carotid artery stenting, achieving sustained patency. Embryologically, neural crest anomalies and persistence of fetal vascular structures, including the ductus caroticus and the ductus arteriosus, may underpin ITCB associated with TOF. Carotid artery stenting in this setting is technically more challenging, as the guide catheter must be positioned unusually low in the thorax, risking proximal slipping of the guiding system into the aorta.