PFO and Risk of Stroke After Surgery
What is the risk of ischemic stroke associated with patent foramen ovale (PFO) at 1 and 2 years after noncardiac surgery?
This was an observational study of 144,563 patients who underwent noncardiac surgery under general anesthesia at three teaching hospitals between 2007 and 2015. Determination of PFO presence was made by International Classification of Diseases (ICD)-9/10 codes. Determination of ischemic stroke incidence was made by medical record review.
PFO was diagnosed preoperatively in 1,160 of 144,563 (0.8%) patients. Within 1 and 2 years after surgery, 1,642 (1.1%) and 2,376 (1.6%) patients had an ischemic stroke. After adjustment for possible confounders, having a PFO was associated with a twofold increased risk of ischemic stroke within 1 year (adjusted odds ratio [aOR], 2.01; 95% confidence interval [CI], 1.51-2.69) and within 2 years (aOR, 2.10; 95% CI, 1.64-2.68).
Observational data have suggested an increased risk of ischemic stroke within 30 days after surgery for patients with PFO compared to patients without PFO. This study suggests that the increased risk of ischemic stroke after surgery for patients with PFO persists at 2 years. However, the observational nature of this study precludes conclusions about causality.
The prevalence of PFO in the general population is approximately 20-25%. The prevalence of identified PFO in this cohort was 0.8%. Therefore, PFO was presumably underdiagnosed in this cohort. The study’s results may be biased if patients with present but undiagnosed PFO had less frequent stroke than those with present and diagnosed PFO. This is certainly possible, as patients with undiagnosed PFO may be generally healthier, less likely to have an echocardiogram, and less likely to have an ischemic stroke after surgery. To help corroborate the results of this study, a large prospective cohort study of presurgical patients, all with baseline echocardiography with bubble study, would be indicated. However, given the low incidence of stroke within 2 years after surgery in all-comers in this study (1.6%), the practical importance of an association between PFO and postoperative stroke may be limited.
Clinical Topics: Congenital Heart Disease and Pediatric Cardiology, Noninvasive Imaging, Prevention, Congenital Heart Disease, CHD and Pediatrics and Arrhythmias, CHD and Pediatrics and Imaging, CHD and Pediatrics and Quality Improvement, Echocardiography/Ultrasound
Keywords: Anesthesia, General, Brain Ischemia, Echocardiography, Foramen Ovale, Patent, Heart Defects, Congenital, Risk, Secondary Prevention, Surgical Procedures, Operative, Stroke, Vascular Diseases
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