This podcast series was developed by Neurology Learning Network with support from Abbott. For more information on reducing stroke recurrence in patients with PFO, visit Abbott’s website.

Amrou Sarraj, MD: Selecting the Right Candidates for PFO Closure to Prevent Stroke Recurrence

In part 3 of this podcast series, Dr Sarraj discusses factors that determine whether PFO closure is beneficial for each patient, scores and imaging modalities that can be used to help determine this, and patient expectations following the procedure (transcript below). Click here to listen to part 1 and part 2 of the podcast series.

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Amrou Sarraj, MD, is an associate professor of neurology at McGovern Medical School at UTHealth in Houston, Texas.

Transcript:

Amrou Sarraj, MD: Good afternoon. This is Dr Amrou Sarraj. I'm an associate professor of neurology at McGovern Medical School at UTHealth in Houston. We're discussing an important subject to patients’ care, neurologists, cardiologists, and general practitioners, which is reducing stroke recurrence among patients with patent foramen ovale.

We will discuss the etiology and special characteristics of the patients with PFO. We will discuss how to approach these patients from a neurologist's standpoint.

We will also discuss the evidence around treatment of strokes due to PFO, the different treatment methods, the evidence supporting the closure of the PFO and, in general, the expectations in how to approach these patients from the physician's standpoint, from the patient's, and what are the guidelines for practice in these patients.

So, how do we identify which patients that would benefit from PFO closure? How do we stratify these patients into high‑risk patients and low‑risk patients? There are different factors that plays into that.

The number one factor, as I mentioned, the PFO morphology, large vs small PFO–so, moderate and large‑size PFO are the ones who benefit.

The number of bubbles, there are certain grading systems for the PFO–there's the Spencer grading system, there's the International Grading System, the International Consensus Criteria are criteria that's used in clinical trials.

However, in general, patients who have significant number of bubbles, shunting from the right to the left–usually more than 20 or more than 30 bubbles or what we call a shower or a curtain of bubbles–are patients at higher risk of shunting and clot. Shunting from the right to the left and having stroke and having atrial septal aneurysm, as mentioned–one of the factors that increased the risk of having a PFO‑mediated stroke.

The other is the patient's characteristics–younger patients, patients without vascular risk factors–that's why the guidelines suggest patients 18 to 60 without another determined reason.

The score that puts those together is the Risk of Paradoxical Embolism, or the RoPE score. It's an 11‑point score, ranging from 0 to 10 that takes into account the usual stroke risk factors–the age, medical history of hypertension, diabetes, a prior stroke, or tobacco use, as well as the stroke location, cortical vs subcortical.

The score is available online, can be calculated for any physician for their patients, and the score actually, yes or no. When you don't have these vascular risk factors, when you are younger in age, you gain points. When you have these vascular risk factors and you are older in age, you do not have these points, so you have lower scores.

The higher score suggests higher likelihood of PFO‑associated stroke, but lower stroke or stroke recurrence because you don't have the vascular risk factors–the lower score suggests stroke of other sources and higher stroke of recurrence because the patient does have underlying vascular risk factors.

In patients with suspected underlying PFO, several diagnostic studies can be done. The first one and the least invasive between the 2 echocardiograms is the transthoracic echocardiogram, which is placing the probe on the chest and checking if there is a PFO.

Higher sensitivity and better assessment can be done with a transesophageal echocardiogram, which also allows for further assessment of the size of the PFO, should it exist, to form measurements of that. And to look further into the left atrial appendage, if there's a thrombus. If there's a left ventricle or thrombus, better assessment than the TTE and to look at the aortic morphology and if there is any atherosclerotic changes.

Another non‑invasive test, which is more liked by neurologists, is the transcranial doppler, TCD, with bubble study. It's based on monitoring both MCAs, both at risk and after performing Valsalva maneuver with injecting agitated saline to monitor for 20 to 30 seconds and see if there is a cross of the–if you can hear the bubble in the MCAs because, if there is an underlying PFO, then there is–after giving the agitated saline through the IV, it would cross through the PFO from the right to the left. It would cross to the brain and you can hear them in the MCAs. Highly sensitive, as mentioned. It could be as sensitive or even better sensitivity based on a prospective study from Ontario, Canada, back in 2014.

It's a non‑invasive test. However, it cannot measure the size of the PFO as compared to the TEE. It can measure the number of the bubbles or how many bubbles crossing is it? As I mentioned, there are grading systems 0 to 10, or more than 10, or a curtain or a shower of bubbles, which is in different systems, different grades, but usually more than 20 to 30 bubbles, which gives an idea about the shunting and the size of the PFO.

In patients with an underlying PFO and suspected cryptogenic stroke or ESUS stroke mediated by the PFO, and after conducting the comprehensive workup that fails to determine another etiology, the neurologist with collaboration with the cardiologist–we have nowadays the heart and brain clinics–should discuss with the patients the possibility of PFO closures.

And as mentioned, those are the less than 60 years old patients with no underlying vascular risk factors and suspected stroke due to the PFO with morphology of the stroke being cortical shower emboli, should discuss the evidence available and that there is a 3.4% reduced stroke recurrence with PFO closure with the potential increase, over 5 years of course due to the stroke recurrence, with the potential of very procedural complications, rate, and increase the atrial fibrillation.

Patients should expect that they will be maintained on medical management along with the PFO closure, which is usually antiplatelet therapy, unless it's contraindicated or unless there is another indication for anticoagulation.

Should patient choose not to close the PFO, then they are expected to be maintained on antiplatelet therapy or anticoagulation, again dependent on the patient's other vascular or non‑vascular risk factors that would indicate either/or. And as mentioned, all patients with PFO, whether they have PFO closure or no closure–they are expected to be on medical management on the long term.

Thank you for listening to this podcast on an important subject for the general practitioner, the cardiologist, and the neurologist.

Reference:
Kent DM, Ruthazer R, Weimar C, et al. An index to identify stroke-related vs incidental patent foramen ovale in cryptogenic stroke. Neurology. 2013;81(7). doi:10.1212/WNL.0b013e3182a08d59