Comparison of atrial septal defect and patent foramen ovale in cryptogenic strokes.

OBJECTIVES

Paradoxical embolism from right-to-left shunt through atrial septal defect (ASD) and patent foramen ovale (PFO) is a well-accepted cause of "cryptogenic" strokes (CS). To better understand the pathogenic role of ASD, we compared ASD patients with CS having a high and low likelihood of being PFO-related.

METHODS

In the Acute Stroke Registry and Analysis of Lausanne, we calculated prevalence of PFO and ASD in CS patients undergoing echocardiography, and calculated odds ratios (OR) when compared to non-CS. Using the Risk of Paradoxical Embolism (RoPE) score, we divided CS PFO patients in high (HL-PFO, RoPE 8-10) and low-likelihood (LL-PFO, RoPE 0-4) PFO-related stroke. We then performed univariate comparison of epidemiological, clinical and radiological variables of ASD patients with both PFO groups.

RESULTS

Among all CS, prevalence of ASD and PFO were 1.3% and 36.8% respectively. When compared to non-CS, ASD and PFO were associated with CS (OR of 5.2, CI= 1.6-16.6, and 2.8, CI= 2.1-3.8). Compared with HL-PFO, ASD patients were older, more often female, had more cardiovascular risk factors and silent strokes. Compared with LL-PFO, ASD patients were younger, more often female, and had less risk factors. No differences were found for clinical and radiological characteristics and clinical outcome.

CONCLUSION

ASD is a rare stroke risk factor for CS. Since characteristics of such patients lie in-between high and low-likelihood paradoxical PFO-strokes, a thorough work-up for other stroke mechanisms is warranted. Individual evaluation of the likelihood of the ASD being causative for stroke may be preferable over routine ASD closure.