Patent foramen ovale and cryptogenic stroke: diagnosis and updates in secondary stroke prevention

Abstract

The patent foramen ovale (PFO), given its high prevalence in the general population and especially in patients with cryptogenic stroke, has long generated investigation and debate on its propensity for stroke by paradoxical embolism and its management for stroke prevention. The pendulum has swung for percutaneous PFO closure for secondary stroke prevention in cryptogenic stroke. Based on a review of current evidence, the benefit from PFO closure relies on careful patient selection: those under the age of 60 years with few to no vascular risk factors and embolic-appearing stroke deemed cryptogenic after thorough evaluation. As these data look towards influencing guideline statements and device approvals in the future, patient selection remains the crucial ingredient for clinical decision making and future trials.

Figure 1

Transcranial Doppler detection of the right-to-left shunt missed by transoesophageal echocardiography with sedation. Microemboli identified as high-intensity transient signals related to the injection of bubbles (agitated saline) can be graded as follows: grade 0, no microemboli detected in 60 s; grade 1, 1–10 microemboli; grade 2, 11–30 microemboli; grade 3, 31–100 microemboli; grade 4, 101–300 microemboli; grade 5, >300 microemboli. (Reproduced from Tobe et al with permission from Elsevier.)

Figure 2

Relationship between the RoPE score and both the PFO-attributable stroke fraction (blue bars) and estimated risk of recurrent cerebral ischaemic events (red bars). Higher RoPE scores are associated with a greater likelihood that the stroke was causally related to PFO, but are also associated with a lower risk of subsequent stroke. PFO, patent foramen ovale; RoPE, Risk of Paradoxical Embolism; TIA, transient ischaemic attack.