Patent foramen ovale in idiopathic pulmonary arterial hypertension: Long-term risk and morbidity

Introduction Little is known about the presence of patent foramen ovale in idiopathic pulmonary arterial hypertension. While there is suspected worsening of hypoxemia confounding assessment and management of pulmonary hypertension, as well as possible increased morbidity from paradoxical emboli, there may be theoretical relief of worsening right-sided pressures by the same mechanism of right-to-left shunting. Methods Retrospective review of consecutive patients diagnosed with idiopathic pulmonary arterial hypertension (WHO Group 1) via right heart catheterization, from 1998 to 2010. All patients also underwent a four chamber transthoracic echocardiogram with agitated saline contrast for the evaluation of patent foramen ovale. Primary clinical data was collected and compared between patients with and without patent foramen ovale along with univariable and multivariable predictors of long term survival. Results One hundred and fifty five patients were included in the study, 42 with patent foramen ovale (27%). Patients with patent foramen ovale were younger at pulmonary arterial hypertension diagnosis and trended towards higher right ventricular systolic pressures on echocardiography and mean pulmonary arterial pressures by right heart catheterization. Predictors of mortality included age, diffusing capacity for carbon monoxide, and severe hypoxemia. Only diffusing capacity and age were predictive of mortality after adjustment for a priori covariables. Conclusion Patent foramen ovale is seen in a quarter of patients with idiopathic pulmonary arterial hypertension and associated with increased prevalence of severe hypoxemia but had no effect on long term survival.