Introduction:
Although most ischaemic strokes are due to cardioembolism, about 25–40% of strokes are cryptogenic. Patent foramen ovale has been associated with cryptogenic stroke; however, the precise mechanism of this association has not been demonstrated. The aim of this study was to evaluate the association between inflammatory markers and cryptogenic stroke in patients with patent foramen ovale.

Material and methods:
We included 206 patients with patent foramen ovale. Ninety-four (45.63%) out of 206 patients had had stroke, and 112 (54.37%) had not had stroke. The ratio of the total neutrophil count to the total lymphocyte count was defined as the neutrophil to lymphocyte ratio, and the ratio of the absolute platelet count to the absolute lymphocyte count was determined as the platelet to lymphocyte count.

Results:
The neutrophil to lymphocyte ratio was significantly higher in patients who had stroke than in those who did not (2.41 ±1.69 vs. 2.19 ±1.74, p = 0.047). Although the platelet to lymphocyte count was also higher in patients who had had stroke than in those who had not, it was not statistically significant (120.94 ±55.45 vs. 118.01 ±52.21, p = 0.729). 1.62 was the cut-off value for neutrophil to lymphocyte ratio to be associated with stroke with 73.4% sensitivity and 45.05% specificity (p = 0.042).

Conclusions:
This study demonstrated that elevated neutrophil to lymphocyte ratio and platelet to lymphocyte count could be associated with cryptogenic stroke in patients with patent foramen ovale.