Incidence and Outcomes of Positive Bubble Contrast Study Results After Transcatheter Closure of a Patent Foramen Ovale.

Objectives: The aim of this study was to assess the incidence of persistently positive results on agitated saline contrast injection after patent foramen ovale (PFO) closure, the underlying mechanism, and management.

Background: Transcatheter intervention to close a PFO is reasonable in highly selected patients younger than 60 years, after a thorough cardioneurological investigation following a cryptogenic stroke, particularly in the presence of thromboembolic disease or in patients at high risk for venous thrombosis. The U.S. Food and Drug Administration approved the Amplatzer PFO Occluder in October 2016 for such an indication. Confirmation of PFO closure is usually verified by an agitated saline contrast injection during an echocardiographic examination. The appearance of bubbles in the left atrium raises the concern of incomplete closure or other sources of shunting.

Methods: The medical records and echocardiograms of patients who were treated with transcatheter closure of a PFO for cryptogenic stroke were reviewed.

Results: From January 1998 through December 2015, 880 patients were taken to the catheter laboratory for PFO closure, of whom 568 patients, 320 men (56.3%), underwent transcatheter closure of a PFO using an Amplatzer PFO Occluder, at a mean age of 48.1 ± 12.9 years. The incidence of right-to-left shunting (RLS) was 19.5% at a mean of 4 months' follow-up, which reduced to 8.4% at 11 ± 2 months. Sources of RLS were identified in 10 (1.8%); pulmonary arteriovenous malformation (n = 4) was the most common etiology, followed by leak through the device (n = 3). All patients with additional sources of RLS were treated percutaneously. At 2-year follow-up, 16 patients (2.8%) persisted with only mildly positive results on agitated saline contrast injection, without an apparent additional source of shunting.

Conclusions: Coexistence of a PFO and an additional lesion responsible for RLS is uncommon, but not rare; the majority are amenable to transcatheter or surgical intervention.