PFO Is Associated With Increased Risk of Ischemic Stroke After Surgery

Adults with a patent foramen ovale (PFO) who undergo noncardiac surgery appear to have a significantly increased risk of perioperative ischemic stroke within 30 days after the procedure, according to research published February 6 in JAMA. Further research is needed to determine whether interventions would decrease this risk, the authors noted.

“An important finding from this study was that the PFO-attributable risk of perioperative stroke was highest among patients with an otherwise low probability of perioperative ischemic stroke, based on coexisting cardiovascular risk factors and intraoperative characteristics,” said Matthias Eikermann, MD, PhD, Professor of Anesthesia at Beth Israel Deaconess Medical Center in Boston, and colleagues.

Matthias Eikermann, MD

To determine whether a preoperatively diagnosed PFO is associated with increased risk of perioperative ischemic stroke, Dr. Eikermann and colleagues conducted a retrospective cohort study. The researchers analyzed data from patients who had undergone surgery between January 1, 2007, and December 31, 2015, at Massachusetts General Hospital or one of two affiliated community hospitals.

Patients who were 18 or older, had undergone surgery under general anesthesia and mechanical ventilation, and had been extubated at the end of the procedure were included. The primary outcome was perioperative ischemic stroke within 30 days of surgery, based on ICD-9 and ICD-10 diagnostic codes and confirmed by medical record review.

The study included 150,198 patients with a mean age of 55. In all, 1,540 patients had a diagnosis of PFO before surgery. Within 30 days of surgery, 850 ischemic strokes occurred among patients with a PFO, compared with 801 ischemic strokes among patients without a PFO.

The estimated risks of stroke were 5.9 for every 1,000 patients with a PFO and 2.2 for every 1,000 patients without a PFO. In addition, patients with a PFO had an increased risk of large-vessel territory stroke and more severe stroke-related neurologic deficits, compared with patients without PFO.

After data adjustments for risk factors of ischemic stroke and multiple sensitivity analyses, including stratified analyses in patients who had received diagnostic tests sensitive for the detection of PFO, the association between PFO and stroke remained consistent.

One limitation of this study was that the cohort included only patients who were extubated at the end of the procedure. It is possible that stroke risk among patients who remain intubated after surgery is different, said the researchers. Another limitation was that only preoperatively diagnosed PFO cases were included.

“Future studies are required to examine if these patients would benefit from intensifying stroke-preventive measures in the perioperative period (eg, an individualized risk–benefit assessment with regards to timing and choice of perioperative antithrombotic therapy, modified transfusion thresholds, or preoperative PFO closure among select patients),” said Dr. Eikermann and colleagues.

—Erica Tricarico

Suggested Reading

Ng PY, Ng AK, Subramaniam B, et al. Association of preoperatively diagnosed patent foramen ovale with perioperative ischemic stroke. JAMA. 2018;319(5):452-462.