How Big is the Hole?

Abstract

Transcranial Doppler (TCD) with agitated saline injection and transesophageal echocardiography (TEE) are used to evaluate cryptogenic stroke and transient ischemic attack (TIA) patients for patent foramen ovale (PFO). The role of the PFO may be to serve as a passageway for emboli from the peripheral venous system to the brain (Figure 1). Alternatively, thrombi may form in situ at the PFO, especially with a concurrent atrial septal aneurysm. Blood coagulopathies can also contribute to clot formation. Clearly, the mere presence of a PFO cannot explain stroke in any given individual. Secondary stroke prevention includes anticoagulation or endovascular closure or both. Management controversies still exist. Regardless, sensitive and specific diagnostic procedures form the bedrock of our understanding. TCD is equal or superior in its sensitivity to the presence of any right-to-left shunt compared with echocardiography.¹ Insurance carriers generally require a registered vascular technologist perform the technical portion of the TCD-PFO test.