Patent foramen Ovale-related paradoxical embolism after noncardiac surgery

Abstract

Patent foramen ovale (PFO) is a remnant of the fetal circulation that remains in a significant portion of the adult population, predisposing to a higher risk of stroke. This risk is further elevated in the postoperative hypercoagulative period. Here we present a case where a patient underwent a total knee arthroplasty and presented with right-sided hemiparesis on post-operative day 2. Subsequently, the patient underwent percutaneous PFO closure with a 25-mm Amplatzer PFO Occluder (Abbott; Chicago, IL, USA). The patient has not had a stroke since the PFO closure. Recent randomized trials have demonstrated superiority of percutaneous PFO closure over standard-of-care medical therapy for secondary prevention of PFO-associated stroke. Since post-operative PFO-associated stroke is under-recognized in clinical practice, further large-cohort studies are needed to evaluate whether PFO screening and device closure would decrease post-operative stroke risk for noncardiac surgeries.

Learning Objective

Patent foramen ovale (PFO) is a remnant of the fetal circulation commonly found in the adult population, which can increase the risk of stroke. Stroke is a complication of PFO, yet closure of this remnant only occurs on a specific case-by-case basis. Further research in this area is required to determine whether a larger population would benefit from PFO closure.

Introduction

A patent foramen ovale (PFO) is a remnant of the fetal circulation present in approximately 25 % of the adult population [1]. Once thought to be benign, this interatrial communication can increase the risk of recurrent stroke in individuals by 1–1.5 % per year [[2], [3]]. Recent studies suggest that for patients undergoing noncardiac surgery the risk of stroke associated with PFO is 10-times higher compared to no PFO [4]. In this report, we describe a case of post-operative PFO-associated stroke after total knee arthroplasty and discuss the current data on PFO-associated stroke following noncardiac surgery under anesthesia.

Case Report

A 61-year-old African-American female with a history of rheumatoid arthritis, hysterectomy, well-controlled type 2 diabetes mellitus, and hypertension was referred to the cardiology department due to a recent embolic stroke of undetermined source. The patient underwent total right knee arthroplasty and on post-operative day 2 developed acute right-sided hemiparesis. Venous ultrasonography of the lower extremities showed no evidence of deep vein thrombosis. An urgent computed tomography scan of the head was initially unrevealing, but brain magnetic resonance imaging revealed small multifocal cerebral defects with infarcts involving bilateral parietal and temporal lobes (Fig. 1), suggestive of cardioembolic stroke. A transesophageal echocardiogram with bubble study revealed a PFO with a large right-to-left shunt (Fig. 1). The patient was referred to the interventional cardiology department and within 3 months underwent percutaneous PFO closure with a 25-mm Amplatzer PFO Occluder (Abbott; Chicago, IL, USA). Four months post-device implant, a follow-up transthoracic echocardiogram showed no evidence of residual interatrial shunting with the device in good position over the atrial septum (Fig. 1). The patient did not have any atrial fibrillation while on inpatient telemetry at the time of the stroke or on follow up electrocardiograms during clinic visits. Two years later, the patient continues to do well following PFO closure with no recurrent stroke.

Fig. 1.

(A) Transesophageal echocardiogram (TEE) with agitated saline bubble study (and after abdominal pressure and release maneuver on patient) showing the right atrium fully opacified by bubbles, with a large right-to-left shunt. (B) TEE bicaval view revealing a PFO with a tunnel length of 13 mm; a PFO > 8–10 mm is considered a long tunnel and associated with higher risk of ischemic stroke. (C) Transthoracic echocardiogram performed 4 months after PFO device closure revealing the Amplatzer PFO Occluder in place with no residual interatrial shunting. (D) Small acute to subacute infarcts primarily in the left frontal lobe with small foci in the right frontal and right parietal lobes. These are associated with mild edema, but no mass effect or hemorrhage. The distribution of these infarcts suggests emboli from the heart.

PFO, patent foramen ovale.

Discussion

Recent randomized trials have demonstrated superiority of percutaneous PFO closure over standard-of-care medical therapy for secondary prevention of PFO-associated stroke [[4], [5], [6]]. Although the presence of a PFO is common in the general population, the 30-day risk of paradoxical embolism associated with PFO in patients undergoing noncardiac surgery, continues to remain under-recognized in clinical practice [[7], [8]]. Patients with PFO reportedly have a 2.6-fold higher risk of ischemic stroke when compared to patients without PFO [OR 2.66 (95 % CI, 1.96–3.63); p < 0.001] [7]. Moreover, patients with a PFO have a higher risk of large vessel territory stroke [relative risk ratio, 3.14 (95 % CI, 2.21–4.48); p < 0.001] and greater stroke-related neurologic deficits measured by US National Institutes of Health Stroke Scale (NIHSS) [median, 4 (interquartile range, 2–10) vs median, 3 (IQR, 1–6) for those without PFO; p = 0.02] [7].

A recent large meta-analysis of 20.8 million patients investigated the risk of perioperative stroke due to PFO versus no PFO, in individuals undergoing noncardiac surgery [6]; the study found that patients with a PFO have a significantly higher incidence of stroke when undergoing orthopedic surgery (OR 15, CI 12.8–19.3), general surgery (OR 14, CI 10.8–19.1), genitourinary surgery (OR 17, CI 10.4–28.8), neurosurgery (OR 4, CI3.3–5.9), and thoracic surgery (OR 10, CI 6–18), when compared to those surgery patients who did not have a PFO [6]. Another observational study by Villablanca et al. similarly reported a 17-fold increased odds of perioperative stroke among all patients undergoing noncardiac surgery who have a PFO (adjusted OR 16.7, 95 % CI 13.9–20.0, p < 0.001) [4]. The risk of stroke associated with PFO after propensity-matched analysis was 5.9 % vs 0.6 % without a PFO (OR 10.1, 95 % CI, 6.47–15.8, p < 0.001) [4].

Conclusion

Our case demonstrated a patient who had PFO-associated stroke two days after total knee arthroplasty, likely mediated by post-operative inflammation and hypercoagulability that led to paradoxical embolism. Since post-operative PFO-associated stroke is under-recognized in clinical practice, further large-cohort studies are needed to evaluate whether PFO screening and device closure would decrease post-operative stroke risk for noncardiac surgeries. A subset of these patients, such as those with a high-risk PFO (i.e. atrial septal aneurysm or large shunt) [[9], [10]], would be a good cohort to start investigating.

Funding Statement

This correspondence received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Conflict of interest

All authors have no conflicts of interest.