Overlooked Trigger of Migraine—Clinical Significance of Small and Medium-Shunt Patent Foramen Ovale

Background: Patent Foramen Ovale (PFO) is a prevalent congenital heart malformation closely linked with migraine. The effect of PFO size on migraine remains controversial. Methods: This study analyzed migraine patients who underwent PFO closure at our institution from January 2020 through December 2022. Based on transthoracic echocardiography (TTE) findings, the patients were classified into two groups through two distinct classification approaches: method (A) permanent shunt (PS) group or non-PS group, and method (B) large shunt under Valsalva maneuver (LSVM) group or small to moderate shunt under Valsalva maneuver (SMSVM) group. Migraine improvement and adverse events after PFO closure were recorded. Results: A total of 201 migraine patients were included in this study, 110 (54.7%) had PS and 118 (58.7%) had LSVM. The PS and LSVM groups experienced less migraine burden (57.1±64.5 vs. 88.5±96.5 hours, P=0.035; 59.7±67.3 vs. 88.9±96.6 hours, P=0.039). The LSVM group had shorter headache episode durations (11.0±8.2 vs. 14.4±12.3 years, P=0.045). The PS and LSVM groups showed less absolute reduction in migraine burden (33.8±55.2 vs. 71.2±84.9 hours, P=0.032; 33.9±50.5 vs. 76.3±92.8 hours, P=0.008). The LSVM group had a lower rate of alleviation (79.7% vs. 95.2%, P=0.018). Medium to large residual shunt (MLRS) and SMSVM were independent predictors of migraine improvement, and a history of cryptogenic stroke (CS) was a predictor of migraine termination. Conclusion: SMSVM PFO in migraine patients has significant clinical implications and positive intervention outcomes. Both SMSVM and MLRS are associated with migraine relief, and a history of CS is a predictor of migraine termination.