Effect of Patent Foramen Ovale in Patients With Pulmonary Hypertension.

Septostomy reduces right ventricular (RV) workload at the expense of hypoxemia in patients with advanced pulmonary hypertension (PH). A patent foramen ovale (PFO) may serve as a "natural" septostomy, but the incidence and impact of a PFO in PH remains uncertain. We prospectively examined echocardiograms in 404 PH patients referred for initial hemodynamic assessment. Patients included had saline bubble injection and if negative repeatinjection after Valsalva maneuver. Echocardiographic and hemodynamic data were examined. Survival was modeled using Kaplan-Meier method. Eisenmenger syndrome or known atrial shunts other than PFO were excluded: 292 patients met entry criteria. A PFO was identified in 16.8% of the entire cohort, 22.9% of pulmonary arterial hypertension (PAH) patients, and 8.6% of Dana Point group 2 PH patients. Right atrial to pulmonary capillary wedge pressure difference was lowest in the latter group (-7.9 ± 7.1 vs -1.7 ± 5.5 mm Hg for all others, p <0.01). Patients with a PFO were younger (53.9 vs 58.6 years, p = 0.02). A PFO was more often present with moderately or severely dilated (p = 0.01) or dysfunctional (p = 0.03) RVs. Six year survival was unchanged by PFO presence for all patients, including those with PAH. Proportional hazards analysis found only age and functional class independently predicted survival (p <0.01). A PFO is identified less often in Dana Point group 2 PH, likely due to inability of Valsalva maneuver to overcome right atrial to pulmonary capillary wedge pressure difference. In conclusion, the incidence of a PFO in the PH population increases with more dilated and dysfunctional RVs, suggesting that the PFO may be stretched open rather than congenital. The presence of a PFO does not impact survival in PH or PAH.