Materiały źródłowe

• #1 The pathophysiology of patent foramen ovale and its related complications – PubMed

  https://pubmed.ncbi.nlm.nih.gov/39134216/

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #2 Patent Foramen Ovale: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/156863-overview

  Patent foramen ovale (PFO) is a flaplike opening between the atrial septa primum and secundum at the location of the fossa ovalis that persists after age 1 year. […] With increasing evidence that PFO is the culprit in paradoxical embolic events, the relative importance of the anomaly is being reevaluated. […] Patent foramen ovale (PFO) is an anatomic interatrial communication with potential for right-to-left shunt. […] PFO is not atrial septal defect because no septal tissue is missing. […] Patent foramen ovale (PFO) is a flaplike opening between the atrial septa primum and secundum at the location of the fossa ovalis that persists after age 1 year. […] Once the pulmonary circulation is established after birth, left atrial pressure increases, allowing functional closure of the foramen ovale.

• #3 Patent Foramen Ovale: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/156863-overview

  This is followed by anatomical closure of the septum primum and septum secundum by the age of 1 year. […] With increasing evidence that PFO is the culprit in paradoxical embolic events, the relative importance of the anomaly is being reevaluated. […] James Lock, MD, postulated that PFO anatomy results in a cul-de-sac between the septa primum and secundum, predisposing individuals to hemostasis and clot formation. […] Any conditions that increase right atrial pressure more than left atrial pressure can induce paradoxical flow and may result in an embolic event. […] This reasoning has greatly altered the previous conception of PFO and has changed management of the condition.

• #4 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  Patent foramen ovale (PFO) is a common abnormality affecting between 20% and 34% of the adult population. For most people, it is a benign finding; however, in some people, the PFO can open widely to enable paradoxical embolus to transit from the venous to arterial circulation, which is associated with stroke and systemic embolisation. […] In a significant proportion of individuals, the primum and secundum atrial septa do not fuse, and the foramen ovale remains incompletely closed. There is a residual, but transitory, communication between the right and left atria, particularly likely to open during actions that cause sudden rises and falls in intrathoracic pressure, such as sneezing, coughing or straining. […] Some PFOs may open widely, providing a conduit for thrombus, air or vasoactive peptides to travel from the venous to arterial circulation causing a paradoxical embolus. This transfer is associated with several clinical phenomena, including cryptogenic stroke, systemic embolus, migraine with aura and decompression sickness in divers.

• #5 Patent foramen ovale – UpToDate

  https://www.uptodate.com/contents/patent-foramen-ovale/print

  Patent foramen ovale (PFO) is a congenital cardiac lesion that frequently persists into adulthood. Although most patients with a PFO are asymptomatic, a variety of clinical manifestations may be associated with PFO, most importantly cryptogenic stroke. […] PFO was found in 25 to 30 percent of individuals in an autopsy study and in a community-based transesophageal echocardiography (TEE) study. […] Probe-patent PFO was present in 27 percent; the prevalence and size were similar in males and females.

• #6 Patent Foramen Ovale: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/156863-overview

  Patent foramen ovale (PFO) is a flaplike opening between the atrial septa primum and secundum at the location of the fossa ovalis that persists after age 1 year. […] With increasing evidence that PFO is the culprit in paradoxical embolic events, the relative importance of the anomaly is being reevaluated. […] Patent foramen ovale (PFO) is an anatomic interatrial communication with potential for right-to-left shunt. […] PFO is not atrial septal defect because no septal tissue is missing. […] Patent foramen ovale (PFO) is a flaplike opening between the atrial septa primum and secundum at the location of the fossa ovalis that persists after age 1 year. […] Once the pulmonary circulation is established after birth, left atrial pressure increases, allowing functional closure of the foramen ovale.

• #7 Atrial septal defect – Wikipedia

  https://en.wikipedia.org/wiki/Atrial_septal_defect

  A patent foramen ovale (PFO) is a remnant opening of the fetal foramen ovale, which often closes after a person’s birth. This remnant opening is caused by the incomplete fusion of the septum primum and the septum secundum; in healthy hearts, this fusion forms the fossa ovalis, a portion of the interatrial septum which corresponds to the location of the foramen ovale in the fetus. […] The mechanism by which a PFO may play a role in stroke is called paradoxical embolism. In the case of PFO, a blood clot from the venous circulatory system is able to pass from the right atrium directly into the left atrium via the PFO, rather than being filtered by the lungs, and thereupon into systemic circulation toward the brain. […] If the ASD is left uncorrected, the pulmonary hypertension progresses and the pressure in the right side of the heart becomes greater than the left side of the heart. This reversal of the pressure gradient across the ASD causes the shunt to reverse a right-to-left shunt. This phenomenon is known as Eisenmenger’s syndrome. Once right-to-left shunting occurs, a portion of the oxygen-poor blood gets shunted to the left side of the heart and ejected to the peripheral vascular system. This causes signs of cyanosis.

• #8 Patent foramen ovale – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/patent-foramen-ovale/symptoms-causes/syc-20353487

  A patent foramen ovale (PFO) is a hole in the heart that didn’t close the way it should after birth. The hole is a small flaplike opening between the upper heart chambers. The upper chambers of the heart are called the atria. […] It’s unclear why the foramen ovale stays open in some people. Genetics may play a role. […] A patent foramen ovale is a small, flaplike opening in the wall between the upper chambers of the heart. It usually causes no symptoms and rarely requires treatment. […] The pressure of the blood pumping through the heart usually forces the flap opening of the foramen ovale to close. In most people, the opening closes sometime during infancy. […] Some studies have found that patent foramen ovales (PFOs) are more common in people with unexplained strokes and migraines with aura. But more research is needed. Usually, there are other reasons for these conditions. It’s often just a coincidence a person also has a PFO.

• #9 Patent foramen ovale pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Patent_foramen_ovale_pathophysiology

  During the 4th week of gestation, formation of the atrial septum begins. Fusion of both septa’s occurs after birth with increased left atrial pressure. The foramen ovale remains patent in some people due to failure of fusion of the septum primum and septum secundum. […] Soon after birth, as an infant takes its first breath, the negative intrathoracic pressure closes the foramen ovale. It may remain open in a number of people due to failure of fusion of the septum primum and septum secundum making the closure incomplete. This patent foramen ovale permits interatrial flow of blood from the right atrium to the left atrium during periods when the right atrial pressure exceeds that of the left atrium, for example, coughing, sneezing or straining. […] It is undetected in a majority of people and may be seen during cardiac investigation.

• #10 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  The overlapping of the primum and secundum atrial septa in a PFO forms a flap valve that usually only opens when the right atrial pressure exceeds the left atrial pressure. PFOs are functionally closed most of the time, as right atrial pressure is usually less than the left atrial pressure. This pressure gradient can be reversed by manoeuvres that change the intrathoracic pressure (e.g. sneezing, coughing or straining to defecate), allowing the PFO to open, and blood, thrombus or any other substance to pass across from the right to left atrium. […] The presumed cause of stroke is paradoxical embolus. As the likely cause is known, the term cryptogenic is a misclassification, but remains in use throughout the literature. […] Translocation of venous thrombus to the arterial circulation under the haemodynamic conditions in which a PFO is open leads to embolic stroke.

• #11 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  The overlapping of the primum and secundum atrial septa in a PFO forms a flap valve that usually only opens when the right atrial pressure exceeds the left atrial pressure. PFOs are functionally closed most of the time, as right atrial pressure is usually less than the left atrial pressure. This pressure gradient can be reversed by manoeuvres that change the intrathoracic pressure (e.g. sneezing, coughing or straining to defecate), allowing the PFO to open, and blood, thrombus or any other substance to pass across from the right to left atrium. […] The presumed cause of stroke is paradoxical embolus. As the likely cause is known, the term cryptogenic is a misclassification, but remains in use throughout the literature. […] Translocation of venous thrombus to the arterial circulation under the haemodynamic conditions in which a PFO is open leads to embolic stroke.

• #12 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  The overlapping of the primum and secundum atrial septa in a PFO forms a flap valve that usually only opens when the right atrial pressure exceeds the left atrial pressure. PFOs are functionally closed most of the time, as right atrial pressure is usually less than the left atrial pressure. This pressure gradient can be reversed by manoeuvres that change the intrathoracic pressure (e.g. sneezing, coughing or straining to defecate), allowing the PFO to open, and blood, thrombus or any other substance to pass across from the right to left atrium. […] The presumed cause of stroke is paradoxical embolus. As the likely cause is known, the term cryptogenic is a misclassification, but remains in use throughout the literature. […] Translocation of venous thrombus to the arterial circulation under the haemodynamic conditions in which a PFO is open leads to embolic stroke.

• #13 Patent Foramen Ovale: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/156863-overview

  This is followed by anatomical closure of the septum primum and septum secundum by the age of 1 year. […] With increasing evidence that PFO is the culprit in paradoxical embolic events, the relative importance of the anomaly is being reevaluated. […] James Lock, MD, postulated that PFO anatomy results in a cul-de-sac between the septa primum and secundum, predisposing individuals to hemostasis and clot formation. […] Any conditions that increase right atrial pressure more than left atrial pressure can induce paradoxical flow and may result in an embolic event. […] This reasoning has greatly altered the previous conception of PFO and has changed management of the condition.

• #14 Patent foramen ovale | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/patent-foramen-ovale?lang=us

  A patent foramen ovale (PFO) is a normal fetal interatrial connection which can persist into adult life. This can cause stroke due to paradoxical embolus. […] Patent foramen ovale is the name given to persistence of the vital fetal channel between the atria which allows blood to bypass the lungs until birth. With the onset of neonatal respiration, left atrial pressure rises and coapts the walls of the channel. Over the ensuing months the walls commonly adhere ensuring permanent closure. At autopsy, up to 34% of adults have probe patency of the PFO which may never have been clinically significant. Long-term elevation of right atrial pressure increases the patency rate (see carcinoid heart disease above). The width, length and shape of the tunnel show marked individual variation which can affect patency. The septum primum forms a flap valve at the fossa ovalis which may be seen on imaging. PFO flow is intermittent whereas an ASD is permanently open, and is due to failed overlap of the septum primum and septum secundum.

• #15 Patent Foramen Ovale – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493151/

  Clinically significant PFOs result in adverse consequences by 2 mechanisms: Serving as a conduit for paradoxical embolization from the venous side to the systemic circulation […] Because of their tunnel-like structure and propensity for stagnant flow, they may serve as a nidus for in situ thrombus formation. […] PFO primarily increases the risk of stroke from a paradoxical embolism. […] The risk for a cryptogenic stroke in patients with PFO increases with the larger defects and the presence of interatrial aneurysm. […] Despite prior reports concerning paradoxical embolism through a PFO, this phenomenon’s magnitude as a risk factor for stroke remains undefined because deep venous thrombosis is infrequently detected in such patients. […] The management of patent foramen ovale is made by an interprofessional team that consists of a pediatrician, cardiologist, interventional radiologist, and a cardiac surgeon. […] The decision to treat depends on the presence of symptoms, size, and presence of complications. […] Today, in high-risk patients, percutaneous methods of closure have evolved.

• #16 A Young female with patent foramen ovale and cryptogenic stroke

  https://www.oatext.com/a-young-female-with-patent-foramen-ovale-and-cryptogenic-stroke.php

  Patent foramen is a residual part of the fetal circulation system. It is an open area in the center of the inter-atrial septum. After birth, when the systemic circulation has been formed, the pressure in the left atrium increases gradually leading to a functional closing. Generally speaking, its closed during the first year after birth. If the childs patent foramen is still not closed until hes more than 3 years old, this phenomenon is called patent foramen ovale (PFO). About 27% of general population, the patent foramen is not closed completely, leaving small cracks. Generally small PFO ( 2 mm), which has no hemodynamic changes, does not cause contradiction embolism mostly. However, in rare cases, due to the emotional changes, the changes of blood pressure, acute severe cough, doing Valsalva gesture, when the pressure in the right heart increases suddenly, which may provoke the right to left shunt. In the study of Steiner et al. showed that medium PFO ( 2 mm) and large PFO ( 4 mm) have higher frequencies to cause cerebral infarction (CI) than small or no PFO. When a person has ASA and PFO, the blood flow nearby becomes irregular, with embolus formed easily. Then embolus from the right heart system travels through the patent foramen ovale into the left heart, flows from the aorta to the systematic system, leading to cerebral infarction.

• #17 A Young female with patent foramen ovale and cryptogenic stroke

  https://www.oatext.com/a-young-female-with-patent-foramen-ovale-and-cryptogenic-stroke.php

  Patent foramen is a residual part of the fetal circulation system. It is an open area in the center of the inter-atrial septum. After birth, when the systemic circulation has been formed, the pressure in the left atrium increases gradually leading to a functional closing. Generally speaking, its closed during the first year after birth. If the childs patent foramen is still not closed until hes more than 3 years old, this phenomenon is called patent foramen ovale (PFO). About 27% of general population, the patent foramen is not closed completely, leaving small cracks. Generally small PFO ( 2 mm), which has no hemodynamic changes, does not cause contradiction embolism mostly. However, in rare cases, due to the emotional changes, the changes of blood pressure, acute severe cough, doing Valsalva gesture, when the pressure in the right heart increases suddenly, which may provoke the right to left shunt. In the study of Steiner et al. showed that medium PFO ( 2 mm) and large PFO ( 4 mm) have higher frequencies to cause cerebral infarction (CI) than small or no PFO. When a person has ASA and PFO, the blood flow nearby becomes irregular, with embolus formed easily. Then embolus from the right heart system travels through the patent foramen ovale into the left heart, flows from the aorta to the systematic system, leading to cerebral infarction.

• #18 Patent Foramen Ovale – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493151/

  Clinically significant PFOs result in adverse consequences by 2 mechanisms: Serving as a conduit for paradoxical embolization from the venous side to the systemic circulation […] Because of their tunnel-like structure and propensity for stagnant flow, they may serve as a nidus for in situ thrombus formation. […] PFO primarily increases the risk of stroke from a paradoxical embolism. […] The risk for a cryptogenic stroke in patients with PFO increases with the larger defects and the presence of interatrial aneurysm. […] Despite prior reports concerning paradoxical embolism through a PFO, this phenomenon’s magnitude as a risk factor for stroke remains undefined because deep venous thrombosis is infrequently detected in such patients. […] The management of patent foramen ovale is made by an interprofessional team that consists of a pediatrician, cardiologist, interventional radiologist, and a cardiac surgeon. […] The decision to treat depends on the presence of symptoms, size, and presence of complications. […] Today, in high-risk patients, percutaneous methods of closure have evolved.

• #19 Patent Foramen Ovale – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493151/

  Clinically significant PFOs result in adverse consequences by 2 mechanisms: Serving as a conduit for paradoxical embolization from the venous side to the systemic circulation […] Because of their tunnel-like structure and propensity for stagnant flow, they may serve as a nidus for in situ thrombus formation. […] PFO primarily increases the risk of stroke from a paradoxical embolism. […] The risk for a cryptogenic stroke in patients with PFO increases with the larger defects and the presence of interatrial aneurysm. […] Despite prior reports concerning paradoxical embolism through a PFO, this phenomenon’s magnitude as a risk factor for stroke remains undefined because deep venous thrombosis is infrequently detected in such patients. […] The management of patent foramen ovale is made by an interprofessional team that consists of a pediatrician, cardiologist, interventional radiologist, and a cardiac surgeon. […] The decision to treat depends on the presence of symptoms, size, and presence of complications. […] Today, in high-risk patients, percutaneous methods of closure have evolved.

• #20 Patent Foramen Ovale: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/156863-overview

  This is followed by anatomical closure of the septum primum and septum secundum by the age of 1 year. […] With increasing evidence that PFO is the culprit in paradoxical embolic events, the relative importance of the anomaly is being reevaluated. […] James Lock, MD, postulated that PFO anatomy results in a cul-de-sac between the septa primum and secundum, predisposing individuals to hemostasis and clot formation. […] Any conditions that increase right atrial pressure more than left atrial pressure can induce paradoxical flow and may result in an embolic event. […] This reasoning has greatly altered the previous conception of PFO and has changed management of the condition.

• #21 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  The overlapping of the primum and secundum atrial septa in a PFO forms a flap valve that usually only opens when the right atrial pressure exceeds the left atrial pressure. PFOs are functionally closed most of the time, as right atrial pressure is usually less than the left atrial pressure. This pressure gradient can be reversed by manoeuvres that change the intrathoracic pressure (e.g. sneezing, coughing or straining to defecate), allowing the PFO to open, and blood, thrombus or any other substance to pass across from the right to left atrium. […] The presumed cause of stroke is paradoxical embolus. As the likely cause is known, the term cryptogenic is a misclassification, but remains in use throughout the literature. […] Translocation of venous thrombus to the arterial circulation under the haemodynamic conditions in which a PFO is open leads to embolic stroke.

• #22 Patent Foramen Ovale (PFO): Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/17326-patent-foramen-ovale-pfo

  Patent foramen ovale (PFO) is a small hole between the upper right and left chambers (atria) of your heart. This hole may let blood flow between the atria. […] Patent foramen ovale is a small hole between the right and left chambers of your heart that allows blood to flow between them. […] Patent foramen ovale lets a small amount of blood flow between the flaps connecting your right and left atrium. Normally these flaps stop blood from flowing between them. […] Usually, patent foramen ovale causes no problems. But PFO may let a blood clot travel from the right to the left side of your heart. Your heart could pump the clot into your body. If the clot reaches your brain, it could cut off the blood supply. This would cause an ischemic stroke. The clot may also damage your other organs, such as your kidneys or your heart.

• #23 A Young female with patent foramen ovale and cryptogenic stroke

  https://www.oatext.com/a-young-female-with-patent-foramen-ovale-and-cryptogenic-stroke.php

  Basing on the points made above, the mechanism of patients with PFO with cryptogenic stroke is still controversial. Some scholars think that paradoxical cerebral embolism is its possible mechanisms. The sudden rise of the pulmonary artery pressure will raise the pressure of the right atrium. When the pressure in the right atrium is greater than the left, the emboli formed in the right will run into the left with blood flow. On this mechanism, the emboli from the venous system can cause cerebral infarction. This principle may also make some points in young people with left to right shunt who are also suffered from cryptogenic stroke. In general, for most of the people with PFO, there is no right-to left shunt, however, when the pressure of the right atrium is increasing suddenly, the emboli can flow from the right atrium to the left.

• #24 A Young female with patent foramen ovale and cryptogenic stroke

  https://www.oatext.com/a-young-female-with-patent-foramen-ovale-and-cryptogenic-stroke.php

  Basing on the points made above, the mechanism of patients with PFO with cryptogenic stroke is still controversial. Some scholars think that paradoxical cerebral embolism is its possible mechanisms. The sudden rise of the pulmonary artery pressure will raise the pressure of the right atrium. When the pressure in the right atrium is greater than the left, the emboli formed in the right will run into the left with blood flow. On this mechanism, the emboli from the venous system can cause cerebral infarction. This principle may also make some points in young people with left to right shunt who are also suffered from cryptogenic stroke. In general, for most of the people with PFO, there is no right-to left shunt, however, when the pressure of the right atrium is increasing suddenly, the emboli can flow from the right atrium to the left.

• #25 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  The overlapping of the primum and secundum atrial septa in a PFO forms a flap valve that usually only opens when the right atrial pressure exceeds the left atrial pressure. PFOs are functionally closed most of the time, as right atrial pressure is usually less than the left atrial pressure. This pressure gradient can be reversed by manoeuvres that change the intrathoracic pressure (e.g. sneezing, coughing or straining to defecate), allowing the PFO to open, and blood, thrombus or any other substance to pass across from the right to left atrium. […] The presumed cause of stroke is paradoxical embolus. As the likely cause is known, the term cryptogenic is a misclassification, but remains in use throughout the literature. […] Translocation of venous thrombus to the arterial circulation under the haemodynamic conditions in which a PFO is open leads to embolic stroke.

• #26 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  The PFO channel briefly provides a communication between the atria. This mechanism is supported by case studies showing thrombus across a PFO. […] There is also an association between cryptogenic stroke and venous thrombosis in patients with a PFO. […] Nonetheless, further randomised trials learned lessons from earlier neutral studies and have demonstrated that PFO closure is superior to medical therapy for the prevention of recurrent stroke. […] Meta-analyses of these trials confirm that PFO closure reduces the risk of ischaemic stroke in patients with a PFO and cryptogenic stroke. […] Patients with atrial septal aneurysm or large shunts may obtain greater benefit. […] There may be a benefit, but it will remain difficult to prove without large randomised trials with very long follow-up periods.

• #27 The pathophysiology of patent foramen ovale and its related complications – PubMed

  https://pubmed.ncbi.nlm.nih.gov/39134216/

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #28 The pathophysiology of patent foramen ovale and its related complications – EM consulte

  https://www.em-consulte.com/it/article/1685847/the-pathophysiology-of-patent-foramen-ovale-and-it

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] PFO-associated pathologies can therefore be divided into (1) paradoxical systemic embolization and (2) right to left shunting (RLS) of blood through the PFO. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #29 Patent Foramen Ovale and Mechanical Ventilation – Revista Española de Cardiología (English Edition)

  https://www.revespcardiol.org/en-patent-foramen-ovale-mechanical-ventilation-articulo-13154121

  PFO has also been implicated in paradoxical embolisms of other kinds: fatty, tumour and air (in decompression accidents) and is associated with migraine, vascular headache and platypnea-orthodeoxia syndrome. […] For that reason, a high PEEP favours left-right shunts through the PFO. The degree of shunt is affected by the anatomy of the right atria, the size of the PFO and the interatrial pressure gradient. […] The usual indication for PFO closure is stroke recurrence, but it is also indicated in platypneaorthodeoxia syndrome with significant hypoxaemia. […] We have presented a case of persistent foramen ovale, a diagnosis to be considered in all patients with hypoxaemic respiratory failure and MV that do not improve or even worsen when PEEP is increases or on a ventilation strategy that causes auto-PEEP.

• #30 The pathophysiology of patent foramen ovale and its related complications – PubMed

  https://pubmed.ncbi.nlm.nih.gov/39134216/

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #31 Patent Foramen Ovale – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493151/

  Patent foramen ovale (PFO) occurs when a remnant of normal fetal anatomy abnormally persists into adulthood. […] If PFO persists into adulthood, it usually leads to right-to-left shunting of deoxygenated blood, which can be symptomatic or asymptomatic. […] Additionally, if a PFO is present and venous thromboembolism (VTE) develops, the PFO can lead to shunting of the VTE into the arterial circulation. […] Patent foramen ovale (PFO) is part of a group of entities known as atrial septal defects and is a remnant of normal fetal anatomy. […] Most adult patients with a PFO are asymptomatic; however, in some adults, PFO may result in an inter-atrial, right-to-left shunting of deoxygenated blood and the potential for shunting venous thromboembolism to the arterial circulation. […] These changes explain the pathophysiologic determinant of several conditions associated with PFO, including cryptogenic (having no other identifiable cause) stroke, decompression sickness, migraine, platypnea-orthodeoxia syndrome, and acute limb ischemia secondary to emboli.

• #32 The pathophysiology of patent foramen ovale and its related complications – EM consulte

  https://www.em-consulte.com/it/article/1685847/the-pathophysiology-of-patent-foramen-ovale-and-it

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] PFO-associated pathologies can therefore be divided into (1) paradoxical systemic embolization and (2) right to left shunting (RLS) of blood through the PFO. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #33 A Young female with patent foramen ovale and cryptogenic stroke

  https://www.oatext.com/a-young-female-with-patent-foramen-ovale-and-cryptogenic-stroke.php

  The TTE of the patient shows a right to left shunt at the atrial level. Its mechanism of cryptogenic stroke may be that the great anger may cause sudden rises of the pulmonary system, which causes the pressure of the right atrium greater than the left. In this way, the embolus may travel from the right atrium to the left, causing cerebral infarction to the patient. Other scholars hold the opinions that the patients with PFO and cryptogenic stroke may have the following mechanism: 1. Atrial arrhythmia might be caused by PFO, which can result in atrial thrombosis; 2. The stagnant blood through within the patent foramen ovale may lead to thrombosis; 3. The high blood condensation state may be caused by PFO. […] Basing on all the evidences mentioned above, we can conclude that the patient with cerebral infarction may be caused by posterior circulation thromboembolism.

• #34 Pathophysiology and Management of Arrhythmias Associated with Atrial Septal Defect and Patent Foramen Ovale | AER Journal

  https://www.aerjournal.com/articles/pathophysiology-and-management-arrhythmias-associated-atrial-septal-defect-and-patent?language_content_entity=en

  Atrial septal defects (ASDs) are among the most common of congenital heart defects and are frequently associated with atrial arrhythmias. Atrial and ventricular geometrical remodelling secondary to the intracardiac shunt promotes evolution of the electrical substrate, predisposing the patient to atrial fibrillation and other arrhythmias. […] The left-to-right shunt enabled by the presence of an ASD results in cardiac remodelling secondary to long-standing haemodynamic overload. It is this geometrical remodelling that plays an important role in the pathogenesis of AAs. Changes in atrial tissue properties, including interstitial fibrosis, increased myocyte size and alterations in ultracellular structure have been described and predispose to AF in particular. […] Electrical remodelling has also been widely described, even in the absence of AA. The P-wave duration and dispersion is increased, with lengthened sinus node recovery time and conduction delay across the crista terminalis, which is likely to play a key role in the arrhythmogenesis of AFL. […] In summary, remodelling of both the right and left atrium contributes to arrhythmogenesis and the heterogeneity of that remodelling process between atria may contribute to the propensity for native arrhythmias in this patient group.

• #35 Pathophysiology and Management of Arrhythmias Associated with Atrial Septal Defect and Patent Foramen Ovale | AER Journal

  https://www.aerjournal.com/articles/pathophysiology-and-management-arrhythmias-associated-atrial-septal-defect-and-patent?language_content_entity=en

  Atrial septal defects (ASDs) are among the most common of congenital heart defects and are frequently associated with atrial arrhythmias. Atrial and ventricular geometrical remodelling secondary to the intracardiac shunt promotes evolution of the electrical substrate, predisposing the patient to atrial fibrillation and other arrhythmias. […] The left-to-right shunt enabled by the presence of an ASD results in cardiac remodelling secondary to long-standing haemodynamic overload. It is this geometrical remodelling that plays an important role in the pathogenesis of AAs. Changes in atrial tissue properties, including interstitial fibrosis, increased myocyte size and alterations in ultracellular structure have been described and predispose to AF in particular. […] Electrical remodelling has also been widely described, even in the absence of AA. The P-wave duration and dispersion is increased, with lengthened sinus node recovery time and conduction delay across the crista terminalis, which is likely to play a key role in the arrhythmogenesis of AFL. […] In summary, remodelling of both the right and left atrium contributes to arrhythmogenesis and the heterogeneity of that remodelling process between atria may contribute to the propensity for native arrhythmias in this patient group.

• #36 Patent Foramen Ovale – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493151/

  Patent foramen ovale (PFO) occurs when a remnant of normal fetal anatomy abnormally persists into adulthood. […] If PFO persists into adulthood, it usually leads to right-to-left shunting of deoxygenated blood, which can be symptomatic or asymptomatic. […] Additionally, if a PFO is present and venous thromboembolism (VTE) develops, the PFO can lead to shunting of the VTE into the arterial circulation. […] Patent foramen ovale (PFO) is part of a group of entities known as atrial septal defects and is a remnant of normal fetal anatomy. […] Most adult patients with a PFO are asymptomatic; however, in some adults, PFO may result in an inter-atrial, right-to-left shunting of deoxygenated blood and the potential for shunting venous thromboembolism to the arterial circulation. […] These changes explain the pathophysiologic determinant of several conditions associated with PFO, including cryptogenic (having no other identifiable cause) stroke, decompression sickness, migraine, platypnea-orthodeoxia syndrome, and acute limb ischemia secondary to emboli.

• #37 Patent Foramen Ovale and Cryptogenic Stroke: Integrated Management

  https://www.mdpi.com/2077-0383/12/5/1952

  Patent foramen ovale (PFO) is a common cardiac abnormality with a prevalence of 25% in the general population. PFO has been associated with the paradoxical embolism causing cryptogenic stroke and systemic embolization. […] Remarkably, accurately evaluating patients to refer to the closure strategy is extremely important. However, the selection of patients for PFO closure is still not so clear. The aim of this review is to update and clarify which patients should be considered for closure treatment. […] A cryptogenic mechanism seems to be involved in 10–40% of all ischemic strokes. PFO is thought to cause about 50% of cryptogenic strokes. […] Nevertheless, other causes can be involved in the pathogenesis of the ischemic event, such as subclinical atherosclerosis, unstable plaques at intracranial and carotid vessels, arterial dissection, vasculitis, hypercoagulable states, other cardioembolic sources and atrial fibrillation (AF).

• #38 European position paper on the management of patients with patent foramen ovale. General approach and left circulation thromboembolism | EuroIntervention

  https://eurointervention.pcronline.com/article/european-position-paper-on-the-management-of-patients-with-patent-foramen-ovale-general-approach-and-left-circulation-thromboembolism

  The presence of a patent foramen ovale (PFO) is implicated in the pathogenesis of a number of medical conditions. […] Pathophysiological processes include paradoxical embolism, thrombus forming within the PFO, left atrial dysfunction, and atrial arrhythmias. […] The association between PFO and cryptogenic left circulation thromboembolism has mainly been addressed in studies including cryptogenic stroke and is strongly supported by epidemiological data, clinical observational studies and by RCTs showing that PFO closure reduces stroke recurrence in comparison with medical therapy. […] However, the evidence has been controversial due to the different role that a PFO can play in different clinical scenarios and to the lack of adequately dimensioned prospective studies. […] The management of patients with cryptogenic left circulation thromboembolism and PFO has been controversial, giving rise to heterogeneous strategies across different local realms in Europe. […] This position paper provides the first largely shared approach for a rational PFO management based on the best available evidence.

• #39 Patent foramen ovale as a cause of cryptogenic ischemic stroke | Ramazanov | Russian neurological journal

  https://www.r-n-j.com/jour/article/view/297?locale=en_US

  A patent foramen ovale from an anatomical and physiological point of view is a normal communication between the atria, which is present in utero and allows oxygenated placental blood to reach the fetal arterial circulation. With incomplete postpartum fusion of the primary and secondary septa, a patent foramen ovale is formed. […] In the last two decades, clinical interest in the problem of the patent foramen ovale is dictated by the fact that its role in the development of such clinical syndromes as ischemic stroke, myocardial infarction, pulmonary embolism, migraine and decompression sickness of divers has been established, as well as the introduction of endovascular techniques for endovascular transcatheter closure of the atrial septal defect. It was found that the frequency of patent foramen ovale detection in patients with cryptogenic stroke is on average 2 times higher than in patients with an established cause of ischemic stroke and ranges from 40% to 50%.

• #40 Patent Foramen Ovale – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493151/

  Clinically significant PFOs result in adverse consequences by 2 mechanisms: Serving as a conduit for paradoxical embolization from the venous side to the systemic circulation […] Because of their tunnel-like structure and propensity for stagnant flow, they may serve as a nidus for in situ thrombus formation. […] PFO primarily increases the risk of stroke from a paradoxical embolism. […] The risk for a cryptogenic stroke in patients with PFO increases with the larger defects and the presence of interatrial aneurysm. […] Despite prior reports concerning paradoxical embolism through a PFO, this phenomenon’s magnitude as a risk factor for stroke remains undefined because deep venous thrombosis is infrequently detected in such patients. […] The management of patent foramen ovale is made by an interprofessional team that consists of a pediatrician, cardiologist, interventional radiologist, and a cardiac surgeon. […] The decision to treat depends on the presence of symptoms, size, and presence of complications. […] Today, in high-risk patients, percutaneous methods of closure have evolved.

• #41 Patent Foramen Ovale Percutaneous Closure: Evolution and Ongoing Challenges

  https://www.mdpi.com/2077-0383/13/1/54

  Patent foramen ovale (PFO) is implicated in the pathogenesis of several medical conditions. […] PFO closure has been established as the cornerstone therapy for patients with cryptogenic stroke and concomitant PFO. […] The concept of cryptogenic stroke was developed to characterize patients without risk factors or cause of stroke and included criteria such as lesion size and localization, which resulted in a subgroup called “Embolic Stroke of Undetermined Source” (ESUS). […] Nevertheless, the pathophysiologic concept underlying paradoxical embolism is not yet totally elucidated. […] As the risk of recurrent stroke in patients with PFO and ASA is higher than it is in patients without PFO or ASA, closing PFO appeared as an attractive strategy to lower this risk. […] Given those observations, European societies suggest percutaneous closure of a PFO in selected patients aged 18 to 65 years with a confirmed cryptogenic stroke, TIA (transient ischemic attack) or systemic embolism; and an estimated high probability of a causal role of the PFO as assessed by clinical, anatomical and imaging features.

• #42 A case of cryptogenic stroke in a young woman with a patent foramen ovale

  https://www1.racgp.org.au/ajgp/2022/june/cryptogenic-stroke-in-a-woman-with-a-patent-forame

  However, PFO remains an important aetiology to consider in cases of cryptogenic stroke, responsible for 42% of cryptogenic strokes in patients aged 55 years and 15% in patients aged 55 years. […] The RoPE score is a 10-point scale used to determine the risk of a PFO being pathogenic in a cryptogenic stroke, and it can also estimate the risk of stroke recurrence in the following two years. […] The patient had a RoPE score of 9, indicating that the risk of the stroke being attributable to her PFO was 88%, with a 2% risk of recurrent cryptogenic stroke in the next two years. […] It is likely that the hypercoagulable state during pregnancy would further increase the risk of PFO-related complications.

• #43

  https://step1.medbullets.com/evidence/14708951

  A patent foramen ovale (PFO) is a frequent remnant of embryological development with clinical importance in thromboembolism, paradoxical embolism, stroke, platypnea-orthodeoxia, decompression sickness, and migraine headache. […] The proposed mechanisms of stroke with PFO include paradoxical embolization, in situ thrombosis within the canal of the PFO, associated atrial arrhythmias, and concomitant hypercoagulable states. […] Successful closure, defined by transesophageal echocardiography, appears to predict freedom from subsequent embolic events.

• #44 Patent foramen ovale as a cause of cryptogenic ischemic stroke | Ramazanov | Russian neurological journal

  https://www.r-n-j.com/jour/article/view/297?locale=en_US

  The patent foramen ovale is etiologically associated with cryptogenic stroke. Possible mechanisms of ischemic stroke in patent foramen ovale patients include in situ thrombosis, paradoxical embolism, and atrial arrhythmias. Transcatheter endovascular closure of patent foramen ovale with anatomical signs of a high risk of cerebrovascular events in combination with antiplatelet therapy are indicated for patients with cryptogenic stroke aged 18 to 60 years as an optimal means of secondary prevention of ischemic stroke.

• #45 Patent Foramen Ovale Percutaneous Closure: Evolution and Ongoing Challenges

  https://www.mdpi.com/2077-0383/13/1/54

  An updated nomenclature related to stroke risk and PFO has been proposed by the PFO International Workup Group, introducing the term “PFO-associated stroke.” […] This entity means a superficial, large, deep or retinal infarct in the presence of a medium- to high-risk PFO without another identified cause. […] One challenging issue remains to properly rule out atrial fibrillation (AF). […] PFO closure is performed in expert centers. […] The femoral vein is the preferred needle-puncture site for the procedure. […] Imaging allows anatomic measurements in order to select the device’s size appropriately. […] Current positions of European and International societies on DCS and PFO are listed in Table 3. […] PFO closure is today the mainstay therapy for patients with cryptogenic stroke and concomitant high-risk PFO.

• #46 Persistent pathology of the patent foramen ovale: a review of the literature | The Medical Journal of Australia

  https://www.mja.com.au/journal/2021/215/2/persistent-pathology-patent-foramen-ovale-review-literature

  A patent foramen ovale (PFO) is an interatrial shunt, with a prevalence of 2034% in the general population. […] While most people do not have secondary manifestations of a PFO, some reported sequelae include ischaemic stroke, migraine, platypnoeaorthodeoxia syndrome and decompression illness. […] Recent trials support PFO closure for ischaemic stroke patients with high risk PFOs and absence of other identified stroke mechanisms. […] PFO closure for other indications such as platypnoeaorthodeoxia syndrome, decompression illness and paradoxical embolism are based largely on case series with good clinical outcomes. […] PFO closure can be performed as a day surgical intervention with high procedural success and low risk of complications.

• #47 Patent foramen ovale – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/patent-foramen-ovale/symptoms-causes/syc-20353487

  A patent foramen ovale (PFO) is a hole in the heart that didn’t close the way it should after birth. The hole is a small flaplike opening between the upper heart chambers. The upper chambers of the heart are called the atria. […] It’s unclear why the foramen ovale stays open in some people. Genetics may play a role. […] A patent foramen ovale is a small, flaplike opening in the wall between the upper chambers of the heart. It usually causes no symptoms and rarely requires treatment. […] The pressure of the blood pumping through the heart usually forces the flap opening of the foramen ovale to close. In most people, the opening closes sometime during infancy. […] Some studies have found that patent foramen ovales (PFOs) are more common in people with unexplained strokes and migraines with aura. But more research is needed. Usually, there are other reasons for these conditions. It’s often just a coincidence a person also has a PFO.

• #48 Neurological disorders associated with patent foramen ovale – Perevezentseva – Kazan medical journal

  https://kazanmedjournal.ru/kazanmedj/article/view/591372

  In the pathogenesis of migraine, impaired cerebral autoregulation and a common genetic basis for the development of migraine in PFO are speculated. […] The association between PFO and TGA, syncope, vertigo, visual disturbances, and neurological pathology in pediatric patients is unclear and requires further research.

• #49 The pathophysiology of patent foramen ovale and its related complications – PubMed

  https://pubmed.ncbi.nlm.nih.gov/39134216/

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #50 Patent foramen ovale presenting with platypnoea-orthodeoxia syndrome and stroke after multi-organ resection | BMJ Case Reports

  https://casereports.bmj.com/content/14/2/e236784

  Platypnoea-orthodeoxia syndrome (POS) is defined by oxygen desaturation and dyspnoea in upright position that improves by lying down. It results from a right to left shunt at the intracardiac or intrapulmonary level. […] We present an unusual mechanism of POS mediated by PFO and presented immediately after extensive surgical operation where many abdominal and pelvic organs were removed. […] The underlying pathophysiology could be related to cardiac causes represented by intracardiac shunts, for example, PFO, ASD and ASD with fenestrations or to pulmonary causes represented by pulmonary parenchymal ventilation/perfusion mismatch, and pulmonary arteriovenous shunts. […] PFO is a congenital heart defect that present in 25% of autopsies and a minority of patients with this heart defect present with stroke; however, 40% of patients with cryptogenic stroke found to have PFO suggesting its involvement by paradoxical embolism rather than being an incidental finding.

• #51 Patent foramen ovale presenting with platypnoea-orthodeoxia syndrome and stroke after multi-organ resection | BMJ Case Reports

  https://casereports.bmj.com/content/14/2/e236784

  Platypnoea-orthodeoxia syndrome (POS) is defined by oxygen desaturation and dyspnoea in upright position that improves by lying down. It results from a right to left shunt at the intracardiac or intrapulmonary level. […] We present an unusual mechanism of POS mediated by PFO and presented immediately after extensive surgical operation where many abdominal and pelvic organs were removed. […] The underlying pathophysiology could be related to cardiac causes represented by intracardiac shunts, for example, PFO, ASD and ASD with fenestrations or to pulmonary causes represented by pulmonary parenchymal ventilation/perfusion mismatch, and pulmonary arteriovenous shunts. […] PFO is a congenital heart defect that present in 25% of autopsies and a minority of patients with this heart defect present with stroke; however, 40% of patients with cryptogenic stroke found to have PFO suggesting its involvement by paradoxical embolism rather than being an incidental finding.

• #52 Patent foramen ovale presenting with platypnoea-orthodeoxia syndrome and stroke after multi-organ resection | BMJ Case Reports

  https://casereports.bmj.com/content/14/2/e236784

  In most cases of POS caused by heart defects, an additional pathology or a thoracoabdominal anatomical abnormality coexist leading to right-to-left shunt even in the absence of persistent high right-heart pressures. […] The presence of PFO only without an associated pathology mostly would not present with positional hypoxia due to the fact that the left atrial pressure is higher than the right atrial pressure preventing right-to-left shunt. […] The occurrence of septal displacement leads to a change in the atrial position that puts the atrial defect directly at the level of blood flow entrance from the inferior vena cava. […] Assuming that thrombi crossed the PFO, this means there is a right-to-left shunt consolidating the diagnosis of POS. […] The use of relevant diagnostic tools confirms the presence of PFO. PFO percutaneous closure has proven to be a safe and a successful treatment for patients with POS, with rapid symptom relief and low complication rates.

• #53 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  A right-to-left shunt, such as a PFO, allows nitrogen bubbles to bypass the pulmonary filter, increasing the risk that usually safe ascents will cause systemic embolisation. […] A longitudinal, non-randomised follow-up study showed that PFO closure reduced both symptomatic neurological events and total brain lesions among recreational divers with PFO and decompression illness, compared with those who continued to dive without closure. […] A recent prospective registry evaluated 489 recreational divers for PFO using transcranial Doppler. This demonstrated that large PFO was a major independent risk factor for unprovoked decompression illness. […] Closure of PFO would be indicated in a young patient presenting with acute MI of embolic source, with otherwise unremarkable coronary arteries and an absence of risk factors for atherosclerosis or atrial fibrillation. […] The evidence for PFO closure is not strong enough to offer a routine recommendation for PFO closure in migraine with aura.

• #54 Patent Foramen Ovale (PFO) Closure: Procedure & Indications

  https://www.icrjournal.com/articles/patent-foramen-ovale-closure-state-art?language_content_entity=en

  A right-to-left shunt, such as a PFO, allows nitrogen bubbles to bypass the pulmonary filter, increasing the risk that usually safe ascents will cause systemic embolisation. […] A longitudinal, non-randomised follow-up study showed that PFO closure reduced both symptomatic neurological events and total brain lesions among recreational divers with PFO and decompression illness, compared with those who continued to dive without closure. […] A recent prospective registry evaluated 489 recreational divers for PFO using transcranial Doppler. This demonstrated that large PFO was a major independent risk factor for unprovoked decompression illness. […] Closure of PFO would be indicated in a young patient presenting with acute MI of embolic source, with otherwise unremarkable coronary arteries and an absence of risk factors for atherosclerosis or atrial fibrillation. […] The evidence for PFO closure is not strong enough to offer a routine recommendation for PFO closure in migraine with aura.

• #55 Patent Foramen Ovale – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493151/

  Patent foramen ovale (PFO) occurs when a remnant of normal fetal anatomy abnormally persists into adulthood. […] If PFO persists into adulthood, it usually leads to right-to-left shunting of deoxygenated blood, which can be symptomatic or asymptomatic. […] Additionally, if a PFO is present and venous thromboembolism (VTE) develops, the PFO can lead to shunting of the VTE into the arterial circulation. […] Patent foramen ovale (PFO) is part of a group of entities known as atrial septal defects and is a remnant of normal fetal anatomy. […] Most adult patients with a PFO are asymptomatic; however, in some adults, PFO may result in an inter-atrial, right-to-left shunting of deoxygenated blood and the potential for shunting venous thromboembolism to the arterial circulation. […] These changes explain the pathophysiologic determinant of several conditions associated with PFO, including cryptogenic (having no other identifiable cause) stroke, decompression sickness, migraine, platypnea-orthodeoxia syndrome, and acute limb ischemia secondary to emboli.

• #56 The pathophysiology of patent foramen ovale and its related complications – PubMed

  https://pubmed.ncbi.nlm.nih.gov/39134216/

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #57 The efficacy and safety of patent Foramen Ovale Closure for Refractory Epilepsy (PFOC-RE): a prospectively randomized control trial of an innovative surgical therapy for refractory epilepsy patients with PFO of high-grade right-to-left shunt | BMC Neurolo

  https://bmcneurol.biomedcentral.com/articles/10.1186/s12883-023-03317-0

  A significant proportion of patients with epilepsy have an unknown etiology and lack effective targeted therapeutic drugs. Patent Foramen Ovale (PFO) induces hypoxia and microembolism, leading to cerebral neurological dysfunction and increased epilepsy risk. […] The mechanism of the impact of the PFO on brain neurofunction has been gradually clarified, and there is enough clinical evidence of the health benefits of PFO closure in patients with cryptogenic stroke and migraines. […] Therefore, considering the close connection between epilepsy, other CNS diseases, and the pathological mechanisms of PFO injury to the CNS, we hypothesized that PFO might be a possible cause of the development of refractory epilepsy, and PFO closure may contribute to relieving epileptic seizures. […] Based on this clinical evidence, we sought to perform a randomized clinical trial (RCT) using PFO closure to improve epileptic seizures in PRE accompanied by PFO of second-grade or higher RLS. […] This study aims to achieve good treatment effects in relieving epileptic symptoms in patients with refractory epilepsy and PFO, including reducing the frequency of postoperative seizures and alleviating seizure symptoms.

• #58

  https://journals.lww.com/jceg/fulltext/2014/24040/how_to_understand_patent_foramen_ovale_clinical.3.aspx

  Patent foramen ovale (PFO) is a remnant of fetal circulation commonly found in healthy population. […] Coexistent atrial septal aneurysm, size of PFO, degree of the shunt, shunt at rest, pelvic deep vein thrombosis, and prothrombotic states could enhance stroke risk in subjects with PFO. […] The role of patent foramen ovale (PFO) as underlying mechanism of neurological syndromes is still debated and patients management is debated as well. […] With the name PFO we actually include a spectrum of different defects that may show various anatomical complexity. Clinical significance of a single PFO depends on its anatomical features, thus a complex PFO can be considered at higher risk for neurological events rather than a simple defect. […] The association between CS and PFO is one of the most controversial issues of the literature, owing to the instance that paradoxical embolism remains frequently a diagnosis of suspicion.

• #59 Closure of Patent Foramen Ovale (PFO) in Elderly Patients

  https://www.uscjournal.com/articles/how-old-too-old-closure-patent-foramen-ovale-older-patients?language_content_entity=en

  Conversely, older patients may also have additional risk factors that predispose to paradoxical embolism, such as acquired hypercoagulable states and immobility leading to venous thromboembolism. […] This raises questions. What is the definition of young? Is there an age cut off beyond which PFO closure should not be offered? Is there additional evaluation that should be considered in older patients before considering closure? […] The prevalence of PFO is almost three times higher in elderly patients with cryptogenic strokes compared with patients of the same age with a known cause of stroke, suggesting that elderly patients may derive benefit from PFO closure. […] Although the RESPECT-LT, CLOSE and REDUCE trials established the superiority of PFO closure versus medical therapy for preventing recurrent ischemic stroke, none of them included patients older than 60 years.

• #60 A case of cryptogenic stroke in a young woman with a patent foramen ovale

  https://www1.racgp.org.au/ajgp/2022/june/cryptogenic-stroke-in-a-woman-with-a-patent-forame

  However, PFO remains an important aetiology to consider in cases of cryptogenic stroke, responsible for 42% of cryptogenic strokes in patients aged 55 years and 15% in patients aged 55 years. […] The RoPE score is a 10-point scale used to determine the risk of a PFO being pathogenic in a cryptogenic stroke, and it can also estimate the risk of stroke recurrence in the following two years. […] The patient had a RoPE score of 9, indicating that the risk of the stroke being attributable to her PFO was 88%, with a 2% risk of recurrent cryptogenic stroke in the next two years. […] It is likely that the hypercoagulable state during pregnancy would further increase the risk of PFO-related complications.

• #61 The pathophysiology of patent foramen ovale and its related complications – PubMed

  https://pubmed.ncbi.nlm.nih.gov/39134216/

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #62 The pathophysiology of patent foramen ovale and its related complications – EM consulte

  https://www.em-consulte.com/it/article/1685847/the-pathophysiology-of-patent-foramen-ovale-and-it

  The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. […] The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. […] PFO-associated pathologies can therefore be divided into (1) paradoxical systemic embolization and (2) right to left shunting (RLS) of blood through the PFO. […] Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. […] In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

• #63 Patent foramen ovale morphology and stroke size

  https://www.openaccessjournals.com/articles/patent-foramen-ovale-morphology-and-stroke-size.html

  This study suggests that PFO size and morphology alone may not serve as reliable parameters for therapeutic decision making. […] The study indicates that, in addition to the fixed anatomical parameters, structural and hemodynamic changes during the cardiac cycle may contribute significantly towards the etiopathogenic potential of a PFO.

• #64 Neurological disorders associated with patent foramen ovale – Perevezentseva – Kazan medical journal

  https://kazanmedjournal.ru/kazanmedj/article/view/591372

  The foramen ovale between the right and left atria remains open in 15-25% of people over 18 years of age and in most of them it does not manifest itself clinically. […] However, the actual contribution of patent foramen ovale to the development of neurological disorders remains a matter of debate. […] Most individuals with PFO do not experience any clinical symptoms. However, this defect is linked to atrial fibrillation, worsening hypoxemia in patients with pulmonary diseases, and various neurological conditions and symptoms. […] Numerous studies have investigated the impact of PFO on the occurrence and progression of cryptogenic stroke and migraine. […] The clinical significance of PFO is potentially high. However, PFO involvement in the development of neurological disorders remains debatable.

• #65 Patent Foramen Ovale Percutaneous Closure: Evolution and Ongoing Challenges

  https://www.mdpi.com/2077-0383/13/1/54

  Patent foramen ovale (PFO) is implicated in the pathogenesis of several medical conditions. […] PFO closure has been established as the cornerstone therapy for patients with cryptogenic stroke and concomitant PFO. […] The concept of cryptogenic stroke was developed to characterize patients without risk factors or cause of stroke and included criteria such as lesion size and localization, which resulted in a subgroup called “Embolic Stroke of Undetermined Source” (ESUS). […] Nevertheless, the pathophysiologic concept underlying paradoxical embolism is not yet totally elucidated. […] As the risk of recurrent stroke in patients with PFO and ASA is higher than it is in patients without PFO or ASA, closing PFO appeared as an attractive strategy to lower this risk. […] Given those observations, European societies suggest percutaneous closure of a PFO in selected patients aged 18 to 65 years with a confirmed cryptogenic stroke, TIA (transient ischemic attack) or systemic embolism; and an estimated high probability of a causal role of the PFO as assessed by clinical, anatomical and imaging features.

• #66 Patent Foramen Ovale Percutaneous Closure: Evolution and Ongoing Challenges

  https://www.mdpi.com/2077-0383/13/1/54

  This recommendation is based on results obtained in several RCTs and subsequent meta-analysis, in which the rate of recurrent stroke was much lower among PFO closure patients compared to those under antithrombotic treatment alone. […] Further observational and randomized studies are warranted to clarify all the remaining issues in PFO closure.

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