Concurrent pulmonary arteriovenous malformation and pulmonary embolism causing stroke: a therapeutic dilemma

Background As pulmonary arteriovenous malformation (PAVM) include a right-to-left shunt, it can be accompanied by fatal complications such as stroke and brain abscess due to paradoxical embolism. A concurrent PAVM and pulmonary embolism (PE) is a rare condition. Therefore, the sequence of management has not been established. Case presentation A 62-year-old female patient was transferred to our hospital with a sporadic simple PAVM and concurrent bilateral PE. On chest computed tomography (CT), the acute PE was extended to the segmental pulmonary artery where the feeding artery of PAVM originated. Despite the anticoagulation, the patient complained of left sided weakness on the fifth day of admission, and magnetic resonance imaging revealed an acute infarction in the right lateral thalamus, which was thought to be caused by paradoxical embolism. This situation could lead to a dilemma between the risk of thrombus migration during PAVM embolization and another embolic event due to delayed shunt occlusion during anticoagulation. After a multidisciplinary discussion, a delayed endovascular embolization was performed for PAVM after confirming the complete resolution of PE with 4 months of anticoagulation. The cause of PE in this patient was eventually diagnosed as antiphospholipid syndrome. Conclusion The authors reported a rare case of concurrent PAVM and PE that led to an embolic stroke during hospitalization. This patient was managed with delayed endovascular embolization for PAVM after an anticoagulation for PE and stroke. It is thought to be valuable in deciding for a treatment plan for this rare condition.

Doppler ultrasound assessment of minor atrial septal defects in patients with paradoxical embolism

Minor atrial septal defect (ASD) may be one of the pathways of paradoxical embolism in the brain. Few scientific papers have investigated the relationship between ASD (excluding patent foramen ovale) and the occurrence of ischemic stroke. There is no definite opinion as to how functionally important such shunts are and how the shunt changes with age. The review analyzes modern ideas about the probability of paradoxical embolism in small ASDs from the viewpoint of pathophysiology, and also demonstrates the technological capabilities of assessing the functional significance of such shunts based on our own clinical observations.

Stroke and Respiratory Failure: Mind the Shunt!

When stroke patients present with respiratory failure, the first thought that clinicians have is that it is probably related to aspiration pneumonia. However, other causes should be considered, such as intracardiac or intrapulmonary shunts, that could present with paradoxical embolism. Paradoxical embolism is a rare entity defined by the occurrence of a venous thrombotic event associated with a systemic arterial embolism. Frequently, paradoxical embolism presents with platypnoea-orthodeoxia syndrome. Platypnoea-orthodeoxia syndrome is uncommon and is characterized by dyspnoea and hypoxaemia induced by orthostatic position, where symptoms and oxygenation are relieved by recumbency. The authors report a case of a patient who presented with an ischaemic stroke and progression to platypnoea-orthodeoxia syndrome with documentation of simultaneous pulmonary embolism and pulmonary arteriovenous malformations.

Fatal disseminated paradoxical embolism in inferior sinus venosus atrial septal defect

Inferior sinus venosus arterial septal defect (ASD) is a rare congenital cardiac anomaly. As with other types of ASDs and patent foramen ovale (PFO), this defect results in arteri-venous shunting with the risk of developing paradoxical embolism (PDE) to the systemic circulation from venous emboli. We report a case of a 67-year-old lady presented to emergency department (ED) with massive pulmonary embolism (PE) and recurrent acute limb ischaemia. On CT pulmonary angiography (CTPA), an incidental finding of inferior sinus venosus ASD was discovered that has caused the PDE. Thrombolysis was administered followed by open mechanical thrombectomy. The patient developed massive lower gastrointestinal bleed post thrombolysis then passed away despite embolization. This case report describes the catastrophic effect of PDE to cause disseminated multisystem thromboembolism. It also emphasizes the importance of early detection of a possible right-to-left shunt in patients presented with recurrent acute limb ischaemia. Transthoracic echocardiography has reduced sensitivity for inferior sinus venosus ASD requiring further assessment with transoesophageal echocardiography in selected cases.

Cryptogenic stroke. Part 2: paradoxical embolism

Cryptogenic stroke (CS) is defined as a subtype of stroke associated with a heterogeneous group of pathogenetic mechanisms that remained undetermined in the course of advanced diagnostic research. One third or fourth of the ischemic strokes is cryptogenic. Paradoxical embolism is considered the important cause of cryptogenic stroke and transient ischaemic attack (TIA) in young patients. It may occur via the following: patent foramen ovale (PFO), atrial septal defect (ASD), and pulmonary arteriovenous malformation (PAVM). When interviewing patients with suspected paradoxical embolism to obtain their health history, a practitioner should consider factors associated with Valsalva maneuvers, deep vein thrombosis/PE or predisposing conditions or situations, as well as symptoms of hereditary hemorrhagic telangiectasia (telangiectasia of the skin and mucous membranes, hemorrhagic syndrome) and pulmonary arteriovenous malformations (PAVMs) (shortness of breath, hemoptysis). If paradoxical embolism is suspected, it is necessary to conduct a stepwise diagnostic search, including transcranial Doppler ultrasound with bubble test, contrast-enhanced transesophageal echocardiography, and CT angiopulmonography. Diagnosis of relevant clinical conditions involves a search of atrial tachyarrhythmias, deep vein thrombosis, and thrombophilia. As the pathogenetic role of ASD and PAVMs in the development of embolic cryptogenic stroke is beyond doubt, the clinical significance of PFO should be determined taking into account several factors, including the presence of deep vein thrombosis/PE, the severity of the right-left shunt, the presence of ASD, the RoPE score, and detection of thrombophilia. The secondary prevention techniques of ischemic stroke or TIA with underlying PFO should be selected on a case-by-case basis, depending on the clinical significance of the anomaly, comorbid pathology, life expectancy of the patient: endovascular occlusion, anticoagulant or antiplatelet therapy. The secondary prevention with underlying ASD and LAVM includes surgical techniques such as endovascular occlusion or open surgery followed by monitoring of their effectiveness.

Abstract 16831: Provoked PFO Shunt And Posterior Circulation Stroke: An Underrecognized Association

Case Presentation: A 50 year old man presented with nausea and weakness. MRI brain showed a small acute infarct in the right pons. CT angiography of the head and neck was unremarkable. No thrombus, vegetation, or inter-atrial communication was seen on transthoracic echocardiogram: LVEF was 55-60% with normal left atrial size. No history of atrial fibrillation, hypertension, diabetes or drug abuse was reported; lower extremity duplex was negative for deep venous thrombosis. TSH was normal. Transesophageal echocardiography showed an aneurysmal atrial septum: agitated saline injection did not demonstrate an inter-atrial communication (figure 1). Repeat saline injection during the same procedure with Valsalva maneuver demonstrated a moderate-sized, provoked right-to-left, patent foramen ovale (PFO) shunt (figure 2). Discussion: Physiologically decreased sympathetic innervation spares posterior cerebral circulation from Valsalva-induced vasoconstriction. The disproportionate increase in posterior cerebral blood flow when venous return/cardiac output increases in the immediate post-strain period explains the association of provoked PFO shunt and paradoxical embolism to posterior circulation. Although the association has been described in literature, it remains underappreciated. Recognition of the association expedited secondary prevention of stroke in this non-elderly patient by circumventing the need to exclude atrial fibrillation on ambulatory rhythm monitoring (3-6 months) before referral for PFO closure.

Abstract 16935: A Rare Case Of COVID-19 Induced Thrombus-in-Transit Going Through A PFO In A Pregnant Patient

Case Presentation: A 42-year-old female in her 24 th week of pregnancy was admitted to an outside hospital with respiratory failure due to COVID-19 pneumonia and was managed with Remdesivir, Dexamethasone, and pharmacological DVT prophylaxis. Her chest CT showed a massive PE. Due to instability, a cesarean section was necessitated, which resulted in delivering a stillborn baby. Two days later, she developed a severe circulatory shock with acute renal failure, not responding to conventional vasopressors/inotropic therapy. VA-ECMO was inserted for hemodynamic stabilization and the patient was transferred to our advanced ICU for further management. Upon arrival, the clinical picture was suggestive of COVID-19- induced thrombotic storm. Furthermore, the patient underwent several imaging studies which showed additional de-novo thromboembolic events in the brain (stroke), pulmonary circuit (PE), and portal circuit (hepatic thrombosis), which were managed medically. A transesophageal echocardiogram was done and revealed a large highly mobile echogenic structure, measuring up to 40 mm, crossing a patent foramen ovale (PFO) highly suggestive of thrombus in transit, in addition to the findings of significantly dilated RA and RV cavities (Figure 1 A, B). The team decided to perform an urgent surgical excision of that highly mobile thrombus accompanied by PFO closure to prevent catastrophic strokes. The thrombus in transit was extracted and was consistent with prior obtained imaging (Figure 1 C, D). Her postoperative course was uncomplicated. With advanced ICU and multidisciplinary care, she was finally discharged home hemodynamically stable on anticoagulation with Apixaban. Discussion: COVID-19 induced thrombus in-transit crossing a PFO is a rare finding and carries a high risk of paradoxical embolism. Multidisciplinary approach in integrating clinical and imaging findings can further help in a timely-manner decision making which improves patient's outcome.

Paradoxial embolism as a cause of ischemic stroke in patient with sinus venosus atrial septal defect

We present a case report of a middle-aged patient with a rare sinus venosus atrial septal defect (ASD) and ischemic stroke that developed due to paradoxical embolism. Occlusion of the anterior cerebral artery led to a stroke with cognitive impairment, acalculia, and apraxia. Diagnostic ultrasound features of this anomaly in suspected cases are discussed. In the presented case, verification of the stroke cause became possible due to the contrast-enhanced computed tomography of the heart. ASD detection made it possible to refer the patient to the surgical treatment necessary to prevent both recurrent cerebral accidents and the progression of pulmonary hypertension, and the prevention of the development of right ventricular heart failure.