(129) Patent Foramen Ovale and Oxygenation in Patients with Cystic Fibrosis

Background: The prevalence of patent foramen ovale (PFO) in the general population is estimated to be around 24% [1]. The prevalence of PFO among patients with cystic fibrosis (CF) is unknown, but potentially elevated pulmonary artery pressure in CF could increase shunting through an existing PFO. This study assessed the prevalence of PFO in patients with CF and evaluated potential associations with hypoxemia, pulmonary function, and mortality.

Methods: We conducted a retrospective study among patients with CF who attended the Adult CF Center at the University of Utah and had an echocardiogram with bubble study performed. For each CF patient with an echocardiogram with bubble study, we identified 1-2 non-CF control patients who were matched in age and sex and had a similar study performed within six months. We performed logistic regression and proportional hazards modeling to understand the impact of a PFO in CF.

Results: We identified 64 patients with CF who had previous echocardiography with bubble study performed. Of these 64 patients, 35 had a PFO (55%). Among 93 non-CF age- and sex-matched controls who had echocardiograms with bubble studies performed at a similar time, 32 (34%) had a PFO. In age- and sex-adjusted logistic regression, patients with CF were more likely to have a PFO (OR 2.4, p=0.012). Patients with CF with PFO more frequently had hypoxemia (OR 5.1, p=0.011). With a linear regression model, we did not find an association of PFO with decreased percent predicted FEV1. Among patients with CF with PFO, 21 patients died from 1998-2021. Among patients with CF without a PFO, 10 patients died and 4 underwent lung transplantation within the same time period. With a proportional hazards regression model, PFO was not associated with increased CF mortality or a combined endpoint of death or lung transplantation.

Conclusions: Our study shows that PFO is more common in patients with CF compared to non-CF patients (Figure 1). Patients with CF with a PFO are more likely to need supplemental oxygen but do not have a lower percent predicted FEV1, suggesting PFOs have an independent association with hypoxemia and the need for supplemental oxygen. We recommend echocardiogram with bubble study at least once in CF patients who require supplemental oxygen. Further study is needed to understand underlying mechanisms. PFOs had no significant association with survival however this needs to be evaluated in a larger study.

Acknowledgements:

References: [1] Koutroulou I, Tsivgoulis G, Tsalikakis D, Karacostas D, Grigoriadis N, Karapanayiotides T. Epidemiology of Patent Foramen Ovale in General Population and in Stroke Patients: A Narrative Review. Front Neurol. 2020 Apr 28;11:281. doi: 10.3389/fneur.2020.00281. PMID: 32411074; PMCID: PMC7198765.