Residual Shunt After PFO Closure and Long-Term Stroke Recurrence

Jun 11, 2020
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Authors:
Deng W, Yin S, McMullin D, et al.
Citation:
Residual Shunt After Patent Foramen Ovale Closure and Long-Term Stroke Recurrence: A Prospective Cohort Study. Ann Intern Med 2020;172:717-725.
Summary By:
Mollie McDermott, MD, MS

Quick Takes

  • Residual shunt may occur in up to 25% of patients after PFO closure, and the association of residual shunt with long-term recurrent stroke/TIA is unknown.
  • In this study, residual shunt, especially moderate- or large-sized shunt, was associated with an increased long-term (~4-year) risk of recurrent stroke/TIA.
  • The overall risk of long-term stroke/TIA across both groups was relatively low, however, occurring in only 7% in the residual shunt group and 2% in the no-shunt group.

Study Questions:

What is the long-term risk of recurrent stroke/transient ischemic attack (TIA) in patients with patent foramen ovale (PFO)-related cryptogenic stroke status/post PFO closure with residual shunt?

Methods:

Eligible patients had had a PFO-related cryptogenic stroke and were undergoing PFO closure to prevent stroke recurrence. Patients were followed at 1, 6, and 12 months and then annually. At each of these visits (and at 24 hours post-closure), a transthoracic echocardiogram with agitated saline was performed to look for residual shunting. The primary outcome was first recurrent ischemic stroke/TIA after PFO closure. A clinical (rather than radiographic) diagnosis of stroke/TIA was permitted.

Results:

A total of 1,078 patients underwent PFO closure and were followed for an average of 3.7 years. Residual shunt was observed in 243 patients (22.5%), with a small shunt in 150 patients (13.9%) and moderate or large shunt in 93 patients (8.6%). The primary outcome of recurrent stroke/TIA was observed in 18 patients in the shunt group (2.32 events per 100 patient-years) and 24 in the no-shunt group (0.75 events per 100 patient-years). After adjustment for potential confounders, residual shunt was associated with a three-times increased risk of stroke/TIA recurrence (adjusted hazard ratio [aHR], 3.01; 95% confidence interval [CI], 1.59-5.69). Compared to no shunt, large and moderate shunts were associated with a greater than four-times higher rate of recurrent stroke/TIA (aHR, 4.28; 95% CI, 2.07-8.88).

Conclusions:

A moderate or large shunt was seen in almost one in ten patients after PFO closure. Residual shunt, especially moderate or large-sized shunt, was associated with an increased long-term risk of recurrent stroke/TIA.

Perspective:

While the relative risk of stroke/TIA with residual shunt compared to no shunt was high, the absolute risk reduction associated with no shunt was relatively low given the low overall rate of observed recurrent stroke/TIA (only 4% of patients across both groups). Shared decision making with stroke patients with residual shunt will be important when deciding whether to pursue redo closure versus medical therapy to prevent recurrent stroke, and the size of the shunt may be a factor in that dialogue.

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: Brain Ischemia, Echocardiography, Foramen Ovale, Patent, Heart Defects, Congenital, Ischemic Attack, Transient, Recurrence, Risk, Secondary Prevention, Stroke, Vascular Diseases


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