Association of Preoperatively Diagnosed Patent Foramen Ovale With Perioperative Ischemic Stroke

IMPORTANCE Perioperative stroke is a major complication for patients undergoing surgery. Patent foramen ovale (PFO) represents a possible anatomical link between venous thrombosis and stroke. OBJECTIVE To determine whether a preoperatively diagnosed PFO is associated with increased risk of perioperative ischemic stroke. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study from Massachusetts General Hospital and 2 affiliated community hospitals between January 1, 2007, and December 31, 2015. Participants were 182 393 consecutive adults undergoing noncardiac surgery with general anesthesia. EXPOSURES Preoperatively diagnosed PFO. MAIN OUTCOMES AND MEASURES Perioperative ischemic stroke occurring within 30 days of surgery; stroke subtype by Oxfordshire Community Stroke Project classification and stroke severity by National Institute of Health Stroke Scale (NIHSS). RESULTS Among the 150 198 patient cases analyzed (median [SD] age, 55 [16] years), 1540 (1.0%) had a diagnosis of PFO before surgery. A total of 850 (0.6%) ischemic strokes occurred within 30 days of surgery (49 [3.2%] among patients with PFO and 801 [0.5%] among patients without PFO). In adjusted analyses, patients with PFO had an increased risk of ischemic stroke compared with patients without PFO (odds ratio, 2.66 [95% CI, 1.96-3.63]; P < .001). The estimated risks of stroke were 5.9 for every 1000 patients with PFO and 2.2 for every 1000 patients without PFO (adjusted absolute risk difference, 0.4%[95% CI, 0.2%-0.6%). Patients with PFO also had an increased risk of large vessel territory stroke (relative risk ratio, 3.14 [95% CI, 2.21-4.48]; P < .001) and a more severe stroke-related neurologic deficit measured by NIHSS (median, 4 [interquartile range {IQR}, 2-10] vs median, 3 [IQR, 1-6] for those without PFO; P = .02). CONCLUSIONS AND RELEVANCE Among adult patients undergoing noncardiac surgery at 3 hospitals, having a preoperatively diagnosed PFO was significantly associated with increased risk of perioperative ischemic stroke within 30 days after surgery. Further research is needed to confirm these findings and to determine whether interventions would decrease this risk.