Cryptogenic cerebral ischemia in young patients is commonly ascribed to paradoxical embolism. We report the clinical case of a young patient with cryptogenic stroke and a patent foramen ovale, undergoing percutaneous closure of atrial septal defect. Contrast transoesophageal echocardiography at the end of the procedure demonstrated massive late residual right-to-left shunt, due to the coexistence of pulmonary arteriovenous fistulas that were subsequently closed. Routinary adoption of contrast transoesophageal echocardiography at the end of patent foramen ovale closure interventions may be useful to detect early and late residual shunts. Late residual shunts may be due to pulmonary fistulas, a well-known risk factor for recurrent thromboembolic events.
