Transesophageal Echocardiography in Cryptogenic Stroke and PFO: The Analysis of Putative High Risk Features From the Risk of Paradoxical Embolism (RoPE) Database

Study Questions:

In patients with cryptogenic stroke (CS) thought likely due to a patent foramen ovale (PFO), are high-risk imaging markers more common?

Methods:

This study evaluated 1,294 patients with CS and PFO undergoing transesophageal echocardiography (TEE) at multiple sites, and compared patients thought more likely to have PFO-attributable CS (n = 637) to patients thought less likely to have a PFO-attributable CS (n = 657). The study used a predictive tool (RoPE Score) to identify patients thought to be more likely versus less likely to have had a PFO-attributable CS based on clinical and imaging variables.

Results:

Between groups more likely versus less likely to have a PFO-attributable CS, there were no differences in the presence of a large shunt size (odds ratio [OR], 0.92; p = 0.53), a hypermobile atrial septum (OR, 0.80; p = 0.45), or a right-to-left shunt at rest (OR, 1.15; p = 0.11) on TEE. Multiple exploratory analyses were also performed across the score strata that demonstrated no trend to a relationship between increasing score and the presence of TEE findings thought to convey increased risk. Further exploratory analyses showed no relationship between combinations of these features and the use of different shunt sizes.

Conclusions:

The authors concluded that previously proposed markers of increased risk on TEE do not appear to be more common in patients with CS thought more likely attributable to a PFO.

Perspective:

Previous literature has suggested that TEE findings may identify patients with a PFO and increased risk of CS. The presence of a large shunt size and a right-to-left shunt at rest should result in a greater proportion of blood flow going through the PFO, which would be thought to increase the odds of an embolus entering the right atrium becoming paradoxical. The absence of a relationship between these high-risk markers and the probability of CS being due to the PFO is intriguing, and suggests that our understanding of the relationship between PFO and CS is incomplete. It is possible that this score does not accurately identify patients more or less likely to have CS due to PFO, just as it is possible that these supposedly ‘high-risk features’ are not associated with stroke pathophysiology. Further, it is conceivable that these features during TEE may not accurately represent baseline hemodynamic status, particularly given changes in preload during sedation and NPO status for TEE. Overall, the present data suggest that these TEE findings should not be used to identify patients at increased risk of CS.

Keywords: Stroke, Embolism, Atrial Septum, Echocardiography, Foramen Ovale


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