Does patent foramen ovale presence procure favourable outcomes in patients with severe rheumatic mitral stenosis?

Mitral stenosis (MS) is tolerated for an extended period in patients with atrial septal defect (ASD) known as Lutembacher syndrome due to depressurizing effect. In a similar way, patients with patent foramen ovale (PFO) may have clinical benefits in severe MS. We aim to evaluate the clinical effects of PFO in rheumatic MS. Transthoracic and transesophageal echocardiography records of the patients with symptomatic severe MS were screened for the period between 2008 and 2019 in a single center. 320 symptomatic patients with severe MS were included and presence of PFO recorded. Left atrial appendix (LAA) thrombotic status was defined as clear, spontaneous echo contrast, and thrombus. Two different statistical models were used to determine the predictors of either smallest (mitral valve area) MVA at symptomatic presentation or more thrombogenic LAA. 34 patients had PFO. Multivariable ordinary least square model demonstrated that increase in systolic pulmonary arterial pressure, ejection fraction and presence of PFO were associated with smaller MVA on presentation. Multivariable proportional odds logistic regression model demonstrated that advanced age, increased left atrial diameter, absence of PFO were associated with more thrombotic status whereas larger MVA was associated with decreased thrombotic status in LAA. Presence of PFO in severe MS results in two clinical benefits as (i) being asymptomatic with smaller MVA and (ii) having less LAA thrombosis probably caused by depressurizing effect on the left atrial pressure. Our study could serve as an example for patient groups with expected symptomatic benefits from left atrium pressure offloading interventions.