Intraoperative Diagnosis and Management of Patent Foramen Ovale

To the Editor: The study by Dr Krasuski and colleagues¹ suggested no benefit in surgically closing PFOs present in patients undergoing cardiac surgery for other reasons. Although we do not support routine closure of asymptomatic PFOs, there are some methodological issues that could confound the interpretation of this study.

The overall number of events in this study was small. The study enrolled patients over a decade (1995-2006), and over this time surgical techniques changed and could influence stroke rates observed. It is unclear whether there was any significant difference in perioperative atrial fibrillation rates between the cohorts or baseline differences in medical therapy such as statin use, both of which could affect stroke rates. It is biologically plausible that PFO closure in the setting of cardiac surgery, which can trigger an intense pro-inflammatory and prothrombotic response,² may create a milieu for clot formation, embolization, and possible strokes.