What is the recommended management for a patient with a history of stroke, right-to-left cardiac shunt, and hyperechoic material in the IVC to reduce the risk of further thromboembolic events?

Management of Recurrent Stroke with Right-to-Left Cardiac Shunt and IVC Thrombus

This patient requires indefinite anticoagulation with apixaban (or another DOAC) given the recurrent stroke, known right-to-left cardiac shunt, and hyperechoic material in the IVC suggesting thrombus, with continuation of current therapy being the appropriate management. 1

Primary Recommendation: Continue Anticoagulation

The decision to continue apixaban indefinitely is strongly supported by the 2021 AHA/ASA guidelines, which recommend indefinite antithrombotic therapy for patients with recurrent unprovoked stroke. 1 This patient has now experienced two stroke events (left cerebellar infarction last year and current bilateral thalamic infarcts), both without atrial fibrillation or other clear provoked etiology beyond the cardiac shunt.

Key Supporting Evidence:

• Patients with a second unprovoked stroke event have extremely high recurrence risk off anticoagulation and warrant indefinite therapy. 1
• The presence of hyperechoic material in the IVC (7 x 9 mm) combined with a known intracardiac shunt creates a high-risk paradoxical embolism pathway. 1
• The echo findings of severe RV enlargement (RV:LV ratio 1.3), moderate pulmonary hypertension (PA pressure 54 mmHg), and dilated IVC with elevated RA pressure (15 mmHg) suggest chronic thromboembolic disease or significant right heart pathology contributing to the shunt mechanism. 1

Addressing the Cerebral Aneurysms

The presence of stable 3 mm saccular aneurysms does NOT contraindicate anticoagulation in this clinical context. 1

Risk-Benefit Analysis:

• Small aneurysms (<7 mm) have annual rupture rates of approximately 0.5-1%, which is substantially lower than this patient's stroke recurrence risk without anticoagulation. 1
• The aneurysms have been stable for over one year on prior anticoagulation (received TNK last year without aneurysm rupture). 2
• The mortality and morbidity from recurrent stroke far exceeds the bleeding risk from small, stable aneurysms. 1, 2

Workup Priorities

Immediate Actions Already Completed Appropriately:

• Lower extremity DVT evaluation (negative) was appropriate given IVC findings. 1
• CT pulmonary angiogram should be performed if not already done to evaluate for pulmonary embolism given the RV dysfunction, pulmonary hypertension, and IVC thrombus. 1

Additional Recommended Evaluation:

• Contrast echocardiography or cardiac MRI should be performed to better characterize the intracardiac shunt anatomy and assess for any LV thrombus, though the normal LV function (EF 65%) makes LV thrombus less likely. 1
• Hypercoagulability workup including antiphospholipid antibodies, lupus anticoagulant, and other prothrombotic factors should be obtained given recurrent events and IVC thrombus. 1
• Repeat brain MRI in 3-6 months to document stability of aneurysms while on anticoagulation. 1

Anticoagulation Specifics

DOAC vs Warfarin:

Apixaban is appropriate for this indication, though the evidence base is stronger for warfarin in the setting of intracardiac thrombus. 1

• For documented LV or intracardiac thrombus, warfarin with INR 2.0-3.0 for at least 3 months is the Class I recommendation. 1
• The safety of DOACs for new intracardiac thrombus (<3 months) is uncertain (Class 2b, LOE C-LD). 1
• However, this patient's IVC thrombus and cardiac shunt represent a different pathophysiology than LV thrombus, and DOACs have proven efficacy in VTE treatment. 1, 3

Practical Management Decision:

Given that the patient is already on apixaban and tolerating it well, continuation is reasonable with close monitoring. 3 Alternatively, transition to warfarin (INR 2.0-3.0) could be considered given the stronger evidence base for intracardiac/IVC thrombus, particularly if the hyperechoic material represents acute thrombus. 1

Addressing Hypoxia and Right Heart Dysfunction

The persistent hypoxia with ambulation requires urgent evaluation for:

• Pulmonary embolism (acute or chronic thromboembolic disease). 1
• Right-to-left shunting through the cardiac defect, which may worsen with increased RA pressure during exertion. 4
• Pulmonary hypertension contributing to V/Q mismatch. 1

Home oxygen is appropriate as a temporizing measure, but the underlying cause must be identified and treated. 1

Device Closure Consideration

Patent foramen ovale (PFO) or atrial septal defect closure should be discussed with interventional cardiology, though anticoagulation takes precedence acutely. 4

• In the BRUISE CONTROL-2 context, if device closure is pursued, anticoagulation can be continued perioperatively with DOACs. 5
• However, device closure does not eliminate the need for anticoagulation in a patient with documented IVC thrombus and recurrent events. 4
• The decision for device closure should be deferred until the acute thrombus burden is addressed and the patient is stable on anticoagulation for at least 3-6 months. 1, 4

Critical Pitfalls to Avoid

Do not discontinue anticoagulation due to concern about the cerebral aneurysms—the stroke recurrence risk is substantially higher than aneurysm rupture risk. 1, 2

Do not assume the right-to-left shunt alone explains the strokes without addressing the IVC thrombus, which requires treatment regardless. 1

Do not delay pulmonary embolism evaluation—the combination of RV dysfunction, pulmonary hypertension, IVC thrombus, and hypoxia is highly concerning for PE. 1

Do not add aspirin to anticoagulation without a specific indication (e.g., recent coronary intervention), as this significantly increases bleeding risk without proven benefit in this context. 1

Do not use bridging with heparin for procedures unless absolutely necessary—if anticoagulation must be interrupted briefly, the risk of recurrent embolism in the first 1-2 weeks is relatively low (2-5%). 2

Monitoring Plan

• INR monitoring not needed on apixaban, but renal function should be checked every 6 months (or more frequently if CrCl <60 mL/min). 3
• Repeat echocardiogram in 3 months to assess IVC thrombus resolution and RV function. 1
• Repeat brain MRI in 3-6 months to ensure aneurysm stability. 1
• Clinical follow-up every 3 months initially, then every 6 months once stable. 1