Quantitative Analysis of Pulmonary Right-to-Left Shunts and Patent Foramen Ovale via Agitated Saline Contrast Transesophageal Echocardiography: Associations With Migraine, Cryptogenic Stroke, and Transient Ischemic Attack.
Growing evidence associates patent foramen ovale right-to-left shunt (PFO-RLS) with conditions including migraine, cryptogenic stroke (CS), and transient ischemic attack (TIA). However, the potential role of pulmonary right-to-left shunt (P-RLS) remains unclear. This study aimed to characterize PFO-RLS and P-RLS using contrast transesophageal echocardiography (cTEE) and analyze their distinct features and intrinsic associations with migraine and CS/TIA.
302 patients with clinically suspected right-to-left shunt (RLS) contrast transesophageal echocardiography (cTEE) between October 2019 and January 2025 were retrospectively analyzed. Target Symptom Group included patients presenting with migraine, cryptogenic stroke (CS), and/or transient ischemic attack (TIA); all other patients comprised the Comparison Group. cTEE was performed to detect and quantitatively evaluate both patent foramen ovale right-to-left shunt (PFO-RLS) and pulmonary right-to-left shunt (P-RLS). We conducted stratified analyses to assess the relationships of PFO-RLS and P-RLS individually with the presence of target symptoms. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with the Target Symptom Group.
All 302 patients were successfully examined using TTE and cTEE. cTEE revealed 165 cases of PFO-RLS and 217 cases of P-RLS. Stratified analyses showed no statistical significance of P-RLS among patients with varying degrees of PFO-RLS between the positive symptom and other symptoms group. PFO-RLS was statistically significant between the two groups in patients with varying degrees of P-RLS. Pulmonary vein shunt and PFO shunt were significantly associated with positive symptoms (p < 0.05) in the univariate analysis; however, only PFO shunt was an independent risk factor in the multivariate analysis (OR 1.363, p < 0.05). Patients with moderate-to-severe dual shunts had the highest proportion(76.5%) of positive symptoms. Further analysis showed no significant interaction (p > 0.05).
cTEE has a good diagnostic value for determining the source of RLS microvesicles. PFO-RLS causes migraine and CS/TIA; the more shunts there are, the more severe the symptoms. Current grading system for right-to-left shunt does not take microbubble size into consideration, although P-RLS is more common, it does not cause severe symptoms. A PFO shunt alone is an independent risk factor for migraine and CS/TIA.
302 patients with clinically suspected right-to-left shunt (RLS) contrast transesophageal echocardiography (cTEE) between October 2019 and January 2025 were retrospectively analyzed. Target Symptom Group included patients presenting with migraine, cryptogenic stroke (CS), and/or transient ischemic attack (TIA); all other patients comprised the Comparison Group. cTEE was performed to detect and quantitatively evaluate both patent foramen ovale right-to-left shunt (PFO-RLS) and pulmonary right-to-left shunt (P-RLS). We conducted stratified analyses to assess the relationships of PFO-RLS and P-RLS individually with the presence of target symptoms. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with the Target Symptom Group.
All 302 patients were successfully examined using TTE and cTEE. cTEE revealed 165 cases of PFO-RLS and 217 cases of P-RLS. Stratified analyses showed no statistical significance of P-RLS among patients with varying degrees of PFO-RLS between the positive symptom and other symptoms group. PFO-RLS was statistically significant between the two groups in patients with varying degrees of P-RLS. Pulmonary vein shunt and PFO shunt were significantly associated with positive symptoms (p < 0.05) in the univariate analysis; however, only PFO shunt was an independent risk factor in the multivariate analysis (OR 1.363, p < 0.05). Patients with moderate-to-severe dual shunts had the highest proportion(76.5%) of positive symptoms. Further analysis showed no significant interaction (p > 0.05).
cTEE has a good diagnostic value for determining the source of RLS microvesicles. PFO-RLS causes migraine and CS/TIA; the more shunts there are, the more severe the symptoms. Current grading system for right-to-left shunt does not take microbubble size into consideration, although P-RLS is more common, it does not cause severe symptoms. A PFO shunt alone is an independent risk factor for migraine and CS/TIA.