External iliac vein stenosis related to cycling has rarely been described as a cause of deep vein thrombosis. Ischemic stroke occurring in this condition due to paradoxical embolus across a preexisting patent foramen ovale (PFO) has yet to be reported. Here we report a case of embolic ischemic stroke in a young, avid cyclist with no known prior medical history.

A 55-year-old right-handed male presented to our institution for a second opinion regarding etiology of his recent ischemic stroke that occurred approximately 1 month earlier. He experienced abrupt onset left lower extremity weakness while cycling. Brain MRI showed two acute cortical infarcts in the right frontal lobe in the right anterior cerebral artery (ACA) territory. A thorough cerebrovascular work up revealed a right-to-left shunt on transesophageal echocardiogram and pelvic magnetic resonance venogram demonstrated 3.5 cm high-grade stenosis of the right external iliac vein, concerning for a possible prior thrombotic event. Transcranial Doppler ultrasound demonstrated a small shunt at rest that was augmented with Valsalva release (Spencer grade 2 and International Consensus Criteria grade 2). Prolonged cardiac monitoring by loop recorder remained negative for atrial fibrillation or flutter. His ischemic stroke was determined to be likely a result of paradoxical emboli originating in the pelvis at the site of right external iliac vein stenosis. The patient opted for PFO closure for secondary stroke prevention, as he wished to continue daily cycling. Clinical follow-up 5 months after the initial stroke revealed no new symptomatic neurologic events.

This is the first case, based on extensive literature review, reporting embolic ischemic strokes in a cyclist with external iliac vein high-grade stenosis. We highlight that it is important for clinicians to consider iliac vein stenosis as a potential cause of embolic stroke of undetermined source, especially in young patients who are avid cyclists.