To describe a rare case of paradoxical embolic stroke secondary to May-Thurner Syndrome (MTS).

MTS occurs with compression of the left common iliac vein by the right common iliac artery, predisposing to deep vein thrombosis (DVT), pulmonary embolism (PE), and in the presence of a patent foramen ovale (PFO), paradoxical stroke. The Risk of Paradoxical Embolism (RoPE) score estimates the likelihood that a PFO found in a patient with cryptogenic stroke is causal, rather than incidental. While useful, the RoPE score does not account for vascular conditions such as MTS.

We report a case of an 87-year-old female with hypertension, diabetes, hyperlipidemia, and chronic DVT, presenting with acute left hemiparesis.  

Emergent head CT was unremarkable. Following the administration of Tenecteplase, her symptoms improved. MRI revealed an acute right parietal stroke and multiple remote cortical infarcts, leading to a diagnosis of embolic stroke of unknown source (ESUS). Cardioembolic work up was initiated. Transesophageal echocardiogram revealed a PFO (RoPE score 2), and a loop recorder was placed. Chronic DVT was noted on lower extremity ultrasound. MRI venogram of the pelvis confirmed the presence of MTS. The patient underwent vein thrombectomy and left common iliac vein stent placement. There were no abnormalities recorded on cardiac monitoring.

MTS is largely underdiagnosed and the combination of a low RoPE score, PFO, and MTS in the context of stroke is not well documented. Our case highlights the importance of considering MTS in patients presenting with cryptogenic stroke or ESUS and PFO, suggesting that this combination could be clinically significant regardless of RoPE score. In many cases, RoPE score is beneficial when considering PFO closure, however, further research is required to clarify this relationship in the setting of MTS and other vascular conditions.