A patient with pulmonary embolism and patent foramen ovale The value of transcranial doppler

The case is presented of a 46 year-old male, obese and a heavy smoker, who presented with acute dyspnoea a few hours after elective arthroscopy of his left knee. He was admitted to the intensive care unit (ICU) because of severe hypoxaemia, and was started on anticoagulant therapy because of intermediate risk of pulmonary embolism. In view of the refractory hypoxaemia that worsened during intense Valsalva manoeuvre, the suspicion of an intracardiac (interatrial) right-to-left shunt was raised, most probably a patent foramen ovale (PFO) or atrial septal defect (ASD). In view of the severe hypoxaemia and the anticoagulant therapy, initial assessment with transcranial Doppler (TCD) examination with bubble test study was deemed preferable and this confirmed a shunt. Subsequent transoesophageal echocardiography (TEE) bubble test assessment demonstrated the presence of a PFO. Recent recommendations favour TCD as the method of choice for detecting PFO because it is non- invasive, cheaper, faster to perform and comparable with TEE in terms of sensitivity and specificity. The introduction of portable ultrasound devices into the everyday hospital routine renders the application of TCD easier for clinicians of various specialties.