Sir,
We present a rare case of acute paradoxical ischemic stroke from patent foramen ovale
(PFO) in the setting of massive pulmonary embolism (PE).
A 69-year-old male presented to the emergency department with signs of shock and questionable
gastrointestinal bleeding. The patient was also noted to have a right inguinal mass
that was being worked up as an outpatient. On clinical examination, the patient had
cardiogenic shock. He underwent computed tomography (CT) chest/abdominal/pelvis for
undifferentiated shock. On CT chest, he was noted to have bilateral lobar PE [Figure
1]. The patient was started on unfractionated heparin drip. Formal echocardiogram
performed showed severe right ventricular strain and obstructive shock. He continued
to deteriorate clinically and subsequently intubated.
Figure 1
Noncontrast computed tomography axial images (arrows) showing bilateral pulmonary
embolism
On arrival at the intensive care unit (approximately 30 min after intubation), the
patient was noted to have bilateral pinpoint pupils. A Stat head CT scan was performed
and showed acute basilar artery occlusion [Figure 2]. Interventional neurologist immediately
performed mechanical thrombectomy with stent retriever of acute thrombus. Given acute
basilar artery occlusion in the setting of PE, we then repeated echocardiogram with
bubble study, which demonstrated large PFO with a right-to-left shunt [Figure 3].
The patient continued to deteriorate from hemodynamic standpoint and eventually was
made comfort care.
Figure 2
(a) Base of skull angiogram showing acute basilar artery thrombus (b) Pontine infarct
due to basilar artery occlusion
Figure 3
Echocardiogram showing bubble study
Venous thromboembolism (VTE) is a frequent complication of malignancy and is the second
most common cause of mortality in cancer patients. All three mechanisms, such as vascular
endothelial damage, stasis of blood flow, and hypercoagulation, contribute to the
development of VTE.[1] In our patient, pelvic vein compression from testicular carcinoma
may have led to venous stasis, VTE, and eventually PE. His hemodynamic compromise
and acute onset of right ventricular dysfunction suggests massive PE. Our patient
faced a unique dilemma given the presence of PFO, which leads to paradoxical embolism
resulting in acute ischemic stroke (AIS).
PFO has a high prevalence of up to 35% in the general population.[2] Although most
individuals with PFO are asymptomatic, paradoxical embolism from PFO may result in
potentially life-threatening complications, including ischemic stroke, myocardial
infarction, or renal infarction.[3] Several studies have confirmed a strong association
between PFO and AIS in the setting of acute PE;[4
5
6] however, the prevention of paradoxical embolism in patients with PFO is still under
discussion. Antithrombotics and percutaneous PFO closure are the mainstay of PFO intervention
for secondary stroke prevention. Currently, mounting evidence suggests that PFO closure
is a more effective strategy than antithrombotic treatment for reducing the risk of
stroke, but percutaneous PFO closure was also associated with an increased risk of
atrial fibrillation.[7
8
9]
According to current guidelines, systemic thrombolysis is the central goal therapy
in the early management of ischemic stroke (initiated within 4.5 hours of symptoms
onset or the time last known to be well).[10] On the other hand, thrombolytic therapy
is only indicated for patient with acute massive pulmonary embolism (defined as systolic
blood pressure <90mmHg or a decrease in systolic blood pressure by ≥ 40mmHg from baseline).[11]
However, due to potential underlying gastrointestinal bleeding and poor functional
reserve, we decided that our patient is not suitable for thrombolysis. We performed
emergent thrombectomy for basilar occlusion and started patient on anticoagulation.
Unfortunately, his condition continued to deteriorate and died from progressive and
worsening obstructive shock and renal failure.
There is no definite recommended treatment of coexistent massive PE and paradoxical
stroke because the cases are rare. Until now, in our search, there are three case
reports of patients with concomitant massive PE and paradoxical embolic stroke successfully
treated with thrombolysis within first few hours of stroke.[12
13
14] In another case report by Naidoo and Hift,[15] unlike the three case reports mentioned
above, the patient improved from thrombolytic treatment 4 days after the onset of
stroke, but the presence of PFO is not determined. With current evidence, thrombolysis
proved to be safe and effective for treatment in patients with coexistent massive
PE and stroke. However, all results are from single-center experience, and none of
the patients have absolute contraindication to thrombolysis, which happened in our
patient.
For massive PE in patients with contraindications for thrombolysis, catheter-directed
interventions seem to be promising options.[16
17
18] On the other hand, mechanical thrombectomy is proven to be safe in patients with
large-vessel occlusion stroke unsuitable for thrombolysis.[19] However, until now,
there is no report of concurrent mechanical thrombectomy for both PE and paradoxical
stroke, and additional research remains difficult due to its rare occurrence. Therefore,
in patients with high risk of VTE, early detection of PFO is paramount, as paradoxical
embolism may lead to devastating complications, especially in patients with contraindications
to systemic thrombolysis. This would certainly improve the outcome of rare but dramatic
condition of paradoxical embolism.
In conclusion, PFO is a strong risk factor for paradoxical embolism that may lead
to devastating complications such as ischemic stroke. Clinicians should always suspect
the possibility of PFO as the culprit for sudden onset of neurological deficits in
patients with PE and VTE. Concomitant PE and paradoxical embolic stroke can be treated
with systemic thrombolysis, but further research is required to confirm its safety
and effectiveness. Percutaneous PFO closures may be a promising approach for secondary
prevention of paradoxical embolic stroke.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
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understand that their names and initials will not be published and due efforts will
be made to conceal their identity, but anonymity cannot be guaranteed.
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Nil.
Conflicts of interest
There are no conflicts of interest.