Paradoxical embolism: Difference between revisions
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Factors that enhance clotting mechanism beyond physiological requirements elevate the risks of incidence of paradoxical embolism e.g. genetic disorders of hypercoagulation (factor V Leiden deficiency, anti-thrombin III deficiency, protein C and S deficiency), increased estrogen levels (pregnancies and use of oral contraceptive pills), immobilization (related to surgery or disability) and malignancies. | Factors that enhance clotting mechanism beyond physiological requirements elevate the risks of incidence of paradoxical embolism e.g. genetic disorders of hypercoagulation (factor V Leiden deficiency, anti-thrombin III deficiency, protein C and S deficiency), increased estrogen levels (pregnancies and use of oral contraceptive pills), immobilization (related to surgery or disability) and malignancies. | ||
==Pathophysiology== | ==Pathophysiology== | ||
The prerequisites for paradoxical embolism include presence of blood clot on the veins and their eventual bypass passage from venous to arterial blood systems through a breach in integrity of separating right and left sides of heart. When already present clot in form of deep vein thrombosis which is mostly in veins of lower extremities dislodges, it traverses through the right side to the left side of heart and eventually through systemic circulation lodges in end-artery. The manifestation of symptoms depend on size of clot and vessels blocked. The most commonly blocked vessels include: | |||
#Cerebral Arteries (leading to stroke) | |||
#Mesenteric Arteries (leading to acute or chronic mesenteric ischemic) | |||
#Femoral Artery (limb ischemic) | |||
#Renal Artery (acute renal failure) | |||
#Coronary Artery (acute myocardial infarction) | |||
==Diagnosis== | ==Diagnosis== | ||
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2) Presence of intracardiac shunt or pulmonary fistula | 2) Presence of intracardiac shunt or pulmonary fistula | ||
3) Arterial | 3) Arterial blockage | ||
=== Echocardiography=== | === Echocardiography=== | ||
Revision as of 04:05, 12 June 2020
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Hira Rehman, MD[2]
Synonyms and keywords: Paradoxical embolization, paradoxical embolus, cryptogenic stroke, crossed embolism
Overview
A paradoxical embolism refers to a phenomenon of dislodging a clot from venous vasculature which traverses through intracardiac or intrapulmonary shunt into systemic circulation. If dislodged into brain, it could cause ischemic stroke with neurological manifestations depending on the site of blockade of intracranial arteries.
Etiology
It can occur from any condition with any condition with breach in a barrier between right and left sided circulation of heart. The most common pre-existing conditions that results in mixing of arterial and venous blood and eventually lead to paradoxical embolism include:
1) Patent Foramen Ovale
2) Atrial Septal Defect
3) Arteriovenous Shunts
4) Ventricular Septal Defects
Factors that enhance clotting mechanism beyond physiological requirements elevate the risks of incidence of paradoxical embolism e.g. genetic disorders of hypercoagulation (factor V Leiden deficiency, anti-thrombin III deficiency, protein C and S deficiency), increased estrogen levels (pregnancies and use of oral contraceptive pills), immobilization (related to surgery or disability) and malignancies.
Pathophysiology
The prerequisites for paradoxical embolism include presence of blood clot on the veins and their eventual bypass passage from venous to arterial blood systems through a breach in integrity of separating right and left sides of heart. When already present clot in form of deep vein thrombosis which is mostly in veins of lower extremities dislodges, it traverses through the right side to the left side of heart and eventually through systemic circulation lodges in end-artery. The manifestation of symptoms depend on size of clot and vessels blocked. The most commonly blocked vessels include:
- Cerebral Arteries (leading to stroke)
- Mesenteric Arteries (leading to acute or chronic mesenteric ischemic)
- Femoral Artery (limb ischemic)
- Renal Artery (acute renal failure)
- Coronary Artery (acute myocardial infarction)
Diagnosis
Three conditions are required to meet clinical diagnosis:
1) Venous source of embolism
2) Presence of intracardiac shunt or pulmonary fistula
3) Arterial blockage
Echocardiography
A bubble study can be useful in establishing the presence of right-to-left shunting in the evaluation of the patient with suspected paradoxical embolism. It should be noted that bidirectional shunting can also be associated with paradoxical embolism.
Treatment
Treatment of paradoxical embolization involves either:
- Closure of the defect in the heart( closure of an atrial septal defect (ASD), ventricular septal defect (VSD), or patent foramen ovale (PFO))
- Anticoagulation
- Placement of a inferior vena cava (IVC) filter
- Discontinuation of birth control pills
- Smoking cessation