The correlation between patent foramen ovale and brain ischemia in plateau residents

BACKGROUND: It has been suggested that patent foramen ovale (PFO) contributes to the majority of cryptogenic stroke cases in young people, however, the direct link is still undetermined. Here we analyzed the correlation between PFO and brain ischemia lesions in a cohort of cases that were long-term residents in the plateau to provide solid evidence to support the causal relation between PFO and brain ischemia lesion or cryptogenic stroke. METHODS: Long-term residents with young age from Qinghai Plateau were recruited and separated by PFO positivity. Brain MRI was used to image 100 PFO positive cases and 100 healthy controls. The diameter of PFO was measured by echocardiography. The location, number and anterior/posterior circulation of ischemia lesions were also evaluated. The correlation between PFO (including positivity and diameter) and brain ischemia lesion (including positivity and other characteristics) was analyzed by chi-square test. Further, the chi-square test for the trend test was used to analyze the linear correlation between these groups. RESULTS: We found a strong correlation between the positivity of PFO and brain ischemia lesion, with 71% of PFO cases showing the presence of brain ischemia lesions, and only 19% for healthy controls (p < 0.001). The diameter of PFO is strongly and linearly correlated with the incidence rate of brain ischemia lesion (RR = 3.737 (95%CI 2.496 to 5.767). CONCLUSION: We found a convincing correlation between the positivity of PFO and brain ischemia lesion in residents of the plateau. Our findings provide another solid evidence of the direct causal relation between PFO and brain ischemia lesion.