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Paradoxical Embolism: Treatment & Medication
Updated: Sep 17, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Treatment
Medical Care
Paradoxical embolism (PDE) treatment involves medical intervention, surgical intervention, or both. The initial treatment is anticoagulation to prevent propagation of an intracardiac clot. The presence of paradoxical embolism (PDE) with PE or atrial clots increases mortality. No difference in survival exists whether patients are treated medically or surgically.
- Anticoagulation can be in the form of heparin, low molecular-weight heparin (LMWH; eg, enoxaparin, tinzaparin), or the new direct thrombin inhibitors (eg, hirudin) in the presence of heparin-induced thrombocytopenia (HIT). The main goal is to prevent the progression of embolic phenomena while awaiting emergent intracardiac embolectomy with PFO closure.
- Thrombolytics are another alternative available therapy when acute cor pulmonale or hemodynamic instability is present because of acute PE. Anticoagulation and thrombolytics can be used in conjunction or separately, depending on the absence of contraindications and as an alternative to surgical intervention if the patient refuses. Thrombolytics include the recombinant tissue-type plasminogen activator (tPA), reteplase, and TNKase.
- Contraindications include intracranial disease, recent surgery, or trauma. An approximate 1% risk of intracranial hemorrhage exists with the use of tPA.
- It has the additional advantage of treating associated PE and acute arterial occlusion of the extremities. This can lead to immediate decrease in pulmonary artery pressure and can reduce the incidence of recurrent paradoxical embolism (PDE).
- Treatment of the underlying cause of increased right atrial pressure is intended to reverse the right-to-left shunt, restoring the hemodynamic homeostasis.
- DVT and PE in conjunction with paradoxical embolism (PDE) can be treated with long-term anticoagulation in the form of warfarin when surgical intervention is not an option. Inferior vena cava interruption with caval filters, such as a Greenfield filter, can be used. However, they are not protective against emboli smaller than 3 mm.
- Antiplatelet therapy may be beneficial if anticoagulants are contraindicated. Options include dipyridamole/aspirin (Aggrenox), clopidogrel (Plavix), dipyridamole (Persantine), and ticlopidine (Ticlid). They also are beneficial in the treatment of TIA, which can be a presentation of paradoxical embolism (PDE).
- Oxygen therapy is indicated for hypoxia.
Surgical Care
Surgical therapies that include embolectomy and intracardiac communication closure (commonly PFO) are the treatments of choice and are used widely in patients with presumed paradoxical embolism (PDE).5
- Surgical embolectomy with closure of a PFO or ASD appears to be the best treatment option for patients with an impending paradoxical embolism (PDE), except in fixed pulmonary hypertension, where indefinite anticoagulation is an acceptable option.
- Transcatheter closure of intracardiac communication is an alternative option to surgical closure.6
- Both surgical closure and long-term anticoagulation therapy have significant associated morbidity and mortality, making transcatheter closure of PFO or ASD a promising alternative to surgical closure and a promising treatment for patients who are unable to tolerate long-term anticoagulation or who are poor surgical candidates.
- Transcatheter closure can be employed using a Bard ClamShell septal occluder device, the buttoned device, or the CardioSEAL septal occluder device. These all are available for transcatheter closure.
- Complications of nonsurgical closure of PFO or ASD for paradoxical embolism (PDE) are intermediate-term risks of recurrent neurologic events due to suboptimal device performance due to malalignment of the device, with significant residual shunting and the development of a displaced fractured device-arm friction lesion. The rate of recurrent stroke or a transient neurological event following the device placement is 3.2% per year.
- Monitoring of patients is achieved with postclosure TEE or TTE using Doppler color mapping or agitated saline solution contrast injection. Residual shunting may eventually lead to surgical closure when recurrent neurologic deficit or stroke complicates transcatheter PFO or ASD closure.
Consultations
- Radiology interventionists can help in the diagnostic evaluation (which may include angiographic/arteriographic studies) of patients with paradoxical embolism (PDE); they can also help in the treatment of these patients with transcatheter device placement for PFO closure.
- A cardiothoracic surgeon should be consulted to remove an intracardiac thrombus to correct impending paradoxical embolism (PDE). Open-heart surgery is an alternative to close the intracardiac communication.
- A vascular surgeon should be consulted for peripheral embolectomy.
- All emboli removed from the peripheral arterial system should be sent to pathology for histological examination because cardiac myxoma is an important differential diagnosis of paradoxical embolism (PDE), and the clinical manifestations (peripheral, visceral, cerebral embolism) are identical.
- Consultation with a pulmonologist and/or intensivist may be useful for patients with paradoxical embolism (PDE) and PE with hemodynamic compromise for positive-pressure ventilation and intensive care monitoring.
- Early (<1 h) evaluation by a neurologist is very important for thrombolysis in acute stroke.
Diet
- Diet depends on the comorbid state of the patient, such as hypertension or diabetes mellitus, and whether the patient is stable enough to tolerate oral feeding or assisted feeding.
- Nasogastric/nasoenteral feeding is appropriate when patients cannot protect their airway.
Activity
- Bedrest: Patients with paradoxical embolism (PDE) should remain in bed until the threat of dislodgement of the thrombus is minimal.
- Restraints: Elderly patients with increased risk of falls or patients who are confused should be protected with restraints or one-on-one monitoring to prevent falls that can lead to bleeding in the presence of anticoagulation.
- Early mobilization is possible in patients who are hemodynamically stable, without risk of falls and without risk of further embolism.
Medication
Paradoxical embolism (PDE) treatment is based on anticoagulation to prevent clot propagation. Anticoagulants, such as heparin and LMWHs (ie, enoxaparin, tinzaparin), are used for acute cases. Lepirudin (direct thrombin inhibitor) is used in HIT. All medications described previously are adjusted in those with compromised renal states.
Warfarin is used for long-term anticoagulation over a period of months.
Thrombolytics are used commonly to lyse a clot in acute arterial occlusion, preventing permanent damage as occurs in ischemic stroke, PE, and arterial occlusion. Dosages for thrombolytics vary depending on the site involved.
Anticoagulants
These agents are used for the treatment of thromboembolic disorders.
Heparin
Augments activity of antithrombin III and prevents conversion of fibrinogen to fibrin. Does not actively lyse but is able to inhibit further thrombogenesis. Prevents reaccumulation of clot after spontaneous fibrinolysis.
Adult
Initial: 40-170 IU/kg IV
Maintenance infusion: 18 IU/kg/h IV; alternatively, 50 IU/kg/h IV initially, followed by continuous infusion of 15-25 IU/kg/h; increase dose by 5 IU/kg/h q4h prn using aPTT results
Pediatric
Initial: 50 IU/kg IV
Maintenance infusion: 15-25 IU/kg/h IV, increase dose by 2-4 IU/kg/h q6-8h prn using aPTT results
Digoxin, nicotine, tetracycline, and antihistamines may decrease effects; NSAIDs, ASA, dextran, dipyridamole, and hydroxychloroquine may increase heparin toxicity
Documented hypersensitivity; subacute bacterial endocarditis; active bleeding; history of HIT
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
In neonates, preservative-free heparin is recommended to avoid possible toxicity (gasping syndrome) by benzyl alcohol, which is used as preservative; caution in severe hypotension and shock; monitor for bleeding in peptic ulcer disease, menstruation, increased capillary permeability, and when administering IM injections
Enoxaparin (Lovenox)
Enhances inhibition of factor Xa and thrombin by increasing antithrombin III activity. In addition, preferentially increases inhibition of factor Xa. Average duration of treatment is 7-14 d.
Adult
1 mg/kg SC q12h; alternatively, 1.5 mg/kg SC qd
Pediatric
Not established; suggested dose is as follows:
<2 months: 0.75 mg/kg/dose SC bid
>2 months: 0.5 mg/kg/dose SC bid
Platelet inhibitors or oral anticoagulants, such as dipyridamole, salicylates, aspirin, NSAIDs, sulfinpyrazone, and ticlopidine, may increase risk of bleeding
Documented hypersensitivity; major bleeding; thrombocytopenia
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
If thromboembolic event occurs despite LMWH prophylaxis, discontinue drug and initiate alternate therapy; elevation of hepatic transaminases may occur but is reversible; heparin-associated thrombocytopenia may occur with fractionated LMWHs; 1 mg of protamine sulfate reverses effect of approximately 1 mg of enoxaparin if significant bleeding complications develop
Tinzaparin (Innohep)
LMWH with antithrombotic effect. It inhibits factors Xa and IIa (thrombin). The primary inhibitory activity is mediated through antithrombin.
Adult
175 IU/kg SC qd at same time each day
Pediatric
Not established
Platelet inhibitors or oral anticoagulants, such as dipyridamole, salicylates, aspirin, NSAIDs, sulfinpyrazone, and ticlopidine, may increase risk of bleeding
Documented hypersensitivity; active major bleeding; thrombocytopenia
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Bleeding diathesis; uncontrolled arterial hypertension; history of recent GI ulceration, diabetic retinopathy, and hemorrhage
Warfarin (Coumadin)
Interferes with hepatic synthesis of vitamin K–dependent coagulation factors.
Used for prophylaxis and treatment of venous thrombosis, PE, and thromboembolic disorders. Tailor dose to maintain an INR in the range of 2-3 with an overlap of 3-5 days of therapeutic aPTT using heparin regimen as previously described.
Adult
5-15 mg/d PO qd for 2-5 d; adjust dose according to desired INR
Pediatric
Administer weight-based dose of 0.05-0.34 mg/kg/d PO; adjust dose according to desired INR
Drugs that may decrease anticoagulant effects include griseofulvin, carbamazepine, glutethimide, estrogens, nafcillin, phenytoin, rifampin, barbiturates, cholestyramine, colestipol, vitamin K, spironolactone, oral contraceptives, and sucralfate
Medications that may increase anticoagulant effects of warfarin include oral antibiotics, phenylbutazone, salicylates, sulfonamides, chloral hydrate, clofibrate, diazoxide, anabolic steroids, ketoconazole, ethacrynic acid, miconazole, nalidixic acid, sulfonylureas, allopurinol, chloramphenicol, cimetidine, disulfiram, metronidazole, phenylbutazone, phenytoin, propoxyphene, sulfonamides, gemfibrozil, acetaminophen, and sulindac
Documented hypersensitivity; severe liver or kidney disease; open wounds or GI ulcers
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Do not switch brands after achieving therapeutic response; caution in active tuberculosis or diabetes; patients with protein C or S deficiency are at risk of developing skin necrosis
Lepirudin (Refludan)
Highly specific direct thrombin inhibitor. Recombinant hirudin derived from yeast cells. Indicated for anticoagulation in HIT and associated thromboembolic disease.
Action is independent of antithrombin III.
It blocks thrombogenic activity of thrombin. Affects all thrombin-dependent coagulation assays (ie, aPTT values increase in dose-dependent manner). Adjust dose based on aPTT ratios (target 1.5-2.5 normal) determined q4h and then qd.
Adult
0.4 mg/kg (not to exceed 44 mg) slow IV bolus over 15-20 sec, then 0.15 mg/kg/h (not to exceed 16.5 mg/h) continuous IV for 2-10 d or longer as indicated
Pediatric
Not established
Thrombolytics, oral anticoagulants (ie, warfarin), antiplatelet agents, penicillin, and cephalosporins may increase risk of bleeding
Documented hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Recent puncture of large vessels or organ biopsy, anomaly of vessels or organs, recent CVA, intracerebral surgery; severe uncontrolled hypertension; bacterial endocarditis; advanced renal impairment; recent major bleeding (ie, intracranial, GI, intraocular, pulmonary)
Thrombolytics
These agents are used to restore circulation through a previously occluded vessel by the rapid and complete removal of a pathologic intraluminal thrombus or embolus that has not been dissolved by the endogenous fibrinolytic system.
Alteplase (Activase)
A tPA used in management of AMI, acute ischemic stroke, and PE. Safety and efficacy with concomitant administration of heparin or aspirin during first 24 h after symptom onset have not been investigated.
Adult
PE: 100 mg IV infusion over 2 h, then restart heparin when aPTT £ twice normal
Cerebral embolism: Infuse 0.9 mg/kg (not to exceed 90 mg) 10% as IV bolus, then remainder infused over 60 min
Pediatric
Not established
Drugs that alter platelet function (aspirin, dipyridamole, abciximab) may increase risk of bleeding prior to, during, or after therapy; may administer heparin with and after alteplase infusions to reduce risk of repeat thrombosis; either heparin or alteplase may cause bleeding complications
Documented hypersensitivity; active internal bleeding; cerebrovascular accident or stroke within last 2 mo; intracranial or intraspinal surgery or trauma; intracranial hemorrhage on pretreatment evaluation; suspicion of subarachnoid hemorrhage, intracranial neoplasm, arteriovenous malformation, or aneurysm; bleeding diathesis; severe uncontrolled hypertension
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Monitor for bleeding, especially at arterial puncture sites, with coadministration of vitamin K antagonists; control and monitor blood pressure frequently during and following administration (when managing acute ischemic stroke); do not use >0.9 mg/kg to manage acute ischemic stroke; doses >0.9 mg/kg may cause ICH
Streptokinase (Streptase)
Acts with plasminogen to convert plasminogen to plasmin. Plasmin degrades fibrin clots, fibrinogen, and other plasma proteins. Increase in fibrinolytic activity that degrades fibrinogen levels for 24-36 h takes place with IV infusion of streptokinase.
Adult
PE
Loading dose: 250,000 IU IV over 30 min
Maintenance: 100,000 IU/h IV for 24 h (if concurrent DVT suspected, administer for 72 h)
DVT
Loading dose: 250,000 IU IV over 30 min
Maintenance: 100,000 IU/h IV for 72 h
Arterial thrombosis or embolism
Loading dose: 250,000 IU IV over 30 min
Maintenance: 100,000 IU/h IV for 24-72 h
Pediatric
Administer as in adults
Antifibrinolytic agents may decrease effects; heparin, warfarin, and aspirin may increase risk of bleeding
Documented hypersensitivity; active internal bleeding; intracranial neoplasm; aneurysm; diathesis; severe uncontrolled arterial hypertension
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution in severe hypertension, IM administration of medications, trauma, or surgery in the previous 10 days; measure hematocrit, platelet count, aPTT, TT, PT, or fibrinogen levels before therapy is implemented; either TT or aPTT should be less than twice the normal control value following infusion of streptokinase and before (re) instituting heparin; do not take blood pressure in the lower extremities because it may dislodge possible deep vein thrombi; monitor PT, aPTT, TT, or fibrinogen 4 h after the initiation of therapy
Reteplase (Retavase)
A recombinant tPA that forms plasmin after facilitating cleavage of endogenous plasminogen.
In clinical trials, has been shown to be comparable with tPA in achieving TIMI 2 or 3 patency at 90 min. Heparin and aspirin are usually given concomitantly and after.
Adult
10 U IV over 2 min, followed 30 min later by a second dose at 10 U IV
Pediatric
Not established
Anticoagulants and antiplatelets may increase risk of bleeding
Documented hypersensitivity; uncontrolled hypertension; recent intracranial surgery; malformation of aneurysm; bleeding diathesis
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in cardiovascular arrhythmias, hypotension, and perfusion arrhythmias
Tenecteplase (TNKase)
Modified version of alteplase (tPA) made by substituting 3 amino acids of alteplase. Has longer half-life and, thus, can be given as single bolus over 5-s infusion instead of 90 min with alteplase.
Appears to cause less non–intracranial bleeding but has similar risk of intracranial bleeding and stroke as alteplase. Base dose using patient weight. Initiate treatment as soon as possible after onset of AMI symptoms. Because tenecteplase contains no antibacterial preservatives, reconstitute immediately before use.
Adult
Give IV bolus over 5 s using body weight, not to exceed 50 mg
<60 kg: 30 mg (6 mL)
60-70 kg: 35 mg (7 mL)
70-80 kg: 40 mg (8 mL)
80-90 kg: 45 mg (9 mL)
>90 kg: 50 mg (10 mL)
Pediatric
Not established
Heparin and vitamin K antagonists, acetylsalicylic acid, dipyridamole, and GP IIb/IIIa inhibitors may increase risk of bleeding if coadministered
Documented hypersensitivity; active internal bleeding; intracranial neoplasm, arteriovenous malformation, or aneurysm; history of cerebrovascular accident; intracranial or intraspinal surgery or trauma within 2 months; known bleeding diathesis; severe uncontrolled hypertension
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution if readministering to patients who have received prior plasminogen activator therapy (may develop immunity); coronary thrombolysis may result in arrhythmias associated with reperfusion but not different from those often seen in ordinary course of AMI (may be managed with standard antiarrhythmic measures); in elderly, weigh benefits of tenecteplase on mortality against risk of increased adverse events, including bleeding; cholesterol embolism is associated with all types of thrombolytic agents, but true incidence is unknown
Antiplatelets
These agents inhibit platelet aggregation and reduce thrombotic stroke in transient ischemia of the brain.
Clopidogrel (Plavix)
Selectively inhibits adenosine diphosphate (ADP) binding to platelet receptor and subsequent ADP-mediated activation of glycoprotein GPIIb/IIIa complex, thereby inhibiting platelet aggregation.
Adult
75 mg PO qd
Pediatric
Not established
Coadministration with naproxen is associated with increased occult GI blood loss; prolongs bleeding time; safety of coadministration with warfarin not established
Documented hypersensitivity; active pathological bleeding, such as peptic ulcer or intracranial hemorrhage
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in patients at increased risk of bleeding from trauma, surgery, or other pathological conditions; caution in patients with lesions with propensity to bleed (such as ulcers)
Ticlopidine (Ticlid)
Second-line antiplatelet therapy for patients who cannot tolerate or fail ASA therapy.
Adult
250 mg PO bid
Pediatric
Not established
Effects may decrease with coadministration of corticosteroids and antacids; toxicity increases when taken concurrently with theophylline, cimetidine, aspirin, and NSAIDS
Documented hypersensitivity; neutropenia or thrombocytopenia; liver damage; active bleeding disorders
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Discontinue if absolute neutrophil count decreases to <1200/mm3 or if platelet count falls to <80,000/mm3
Dipyridamole 200 mg/aspirin 25 mg (Aggrenox)
Combination antiplatelet agent using additive antiplatelet effects of dipyridamole and aspirin.
Dipyridamole acts via adenosine-platelet A2-receptor system, while aspirin inhibits platelet aggregation by irreversible inhibition of cyclooxygenase system and thus inhibits generation of thromboxane A2, a powerful enhancer of platelet aggregation and vasoconstriction.
Adult
1 cap PO bid
Pediatric
Not established
Diminishes effects of beta-blockers, ACE inhibitors, cholinesterase inhibitors, and diuretics; increased risk of bleeding with anticoagulants, antineoplastic agents, and NSAIDs; increases effect of antidiabetic agents; increased aspirin toxicity with corticosteroids; increases toxicity of methotrexate; aspirin added to treatment regimen that includes valproic acid increases valproic acid toxicity; aspirin discontinued from treatment regimen that includes valproic acid decreases effectiveness of valproic acid
Documented hypersensitivity; NSAIDS allergy; asthma; rhinitis; nasal polyps;
Reye syndrome; coagulation abnormalities; pregnancy (especially third trimester)
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Pregnancy category D (aspirin) and B (dipyridamole); caution in coronary artery disease, hepatic insufficiency, hypotension, renal failure, recent MI, unstable angina, GI ulcers, or bleeding peptic ulcers; discontinue if dizziness or tinnitus occur
More on Paradoxical Embolism |
| Overview: Paradoxical Embolism |
| Differential Diagnoses & Workup: Paradoxical Embolism |
 Treatment & Medication: Paradoxical Embolism |
| Follow-up: Paradoxical Embolism |
| Multimedia: Paradoxical Embolism |
| References |
| Further Reading |
| « Previous Page | Next Page » |
References
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Further Reading
Clinical guidelines
Deep venous thrombosis.
Finnish Medical Society Duodecim - Professional Association. 2001 Apr 30 (revised 2006 Apr 27). Various pagings. NGC:004983
Guidelines on the diagnosis and management of pericardial diseases. The task force on the diagnosis and management of pericardial diseases of the European Society of Cardiology.
European Society of Cardiology - Medical Specialty Society. 2004 Jan. 28 pages. NGC:003524
Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease.
Global Initiative for Chronic Obstructive Lung Disease - Disease Specific Society
National Heart, Lung, and Blood Institute (U.S.) - Federal Government Agency [U.S.]
World Health Organization - International Agency. 2006 (revised 2007). 109 pages. [NGC Update Pending] NGC:006275
Clinical trials
PC-Trial: Patent Foramen Ovale and Cryptogenic Embolism
Risk of Stroke in Pulmonary Embolism With a Patent Foramen Ovale (PFO)
Related eMedicine topics
Patent Foramen Ovale
Atrial Septal Defect, Patent Foramen Ovale
Venous Air Embolism
Pulmonary Embolism
Deep Vein Thrombosis, Lower Extremity
Keywords
paradoxical embolism, PDE, deep vein thrombosis, DVT, deep venous thrombosis, PFO, patent foramen ovale, thromboembolic disease, embolism
