Management of Stroke 6 Hours Post-Mitral Valve Repair
Immediately obtain an urgent CT scan of the brain to rule out hemorrhage, and if the stroke is non-hemorrhagic, initiate anticoagulation therapy with heparin. 1
Immediate Diagnostic Evaluation
Perform urgent non-contrast CT brain scan to differentiate hemorrhagic from ischemic stroke, as this fundamentally determines all subsequent management decisions. 1
Assess for air embolism as the etiology, which is a recognized complication of mitral valve procedures due to inadequate de-airing techniques or device manipulation. 2 Air embolism requires fundamentally different treatment than thrombotic stroke.
Obtain transesophageal echocardiography (TEE) to evaluate for residual thrombus on the repair site, valve dysfunction, or ongoing embolic sources. 1
Management Based on Stroke Etiology
If Air Embolism is Suspected:
Coordinate immediate transfer to a hyperbaric oxygen therapy (HBOT) facility while stabilizing the patient, as HBOT is the standard treatment for iatrogenic air embolism and can dramatically increase oxygen delivery to ischemic tissue. 2
HBOT is specifically recommended by the American Heart Association/American Stroke Association for ischemic neurological symptoms secondary to air embolism, though it is NOT recommended for routine ischemic stroke. 2
Maintain adequate anticoagulation (activated clotting time 200-300 seconds) to minimize concurrent thrombus formation. 2
If Non-Hemorrhagic Thrombotic Stroke:
Initiate anticoagulation with unfractionated heparin without a loading dose once the CT scan confirms absence of hemorrhage. 1
Begin heparin when the aPTT has decreased to less than twice the normal control value, targeting an aPTT of 1.5 to 2 times normal (55 to 80 seconds). 1
The initial heparin dosage should be approximately 1,300 U/hour, with average total dosage of 20,000 to 40,000 U/24 hours. 1
Monitor aPTT closely: check four times every 6 hours for the first 24 hours, then three times every 8 hours, then daily due to rapidly changing levels of fibrinogen and heparin binding proteins. 1
Critical Timing Considerations
Do NOT administer thrombolytic therapy for the stroke itself in this post-operative setting, as the patient is at extremely high risk for hemorrhagic complications. 1
The 6-hour timeframe is within the window where endovascular thrombectomy could theoretically be considered for large vessel occlusion in non-surgical patients, but this is contraindicated immediately post-cardiac surgery due to bleeding risk. 1
Repeat Imaging Protocol
Obtain a second CT scan at 36 to 48 hours after stroke onset to definitively rule out delayed hemorrhagic transformation before considering any surgical intervention. 1
If both CT scans confirm non-hemorrhagic stroke, surgical re-exploration or revision may be performed 72 hours after the stroke if clinically indicated. 1
Transition to Long-Term Anticoagulation
Begin warfarin simultaneously with heparin once the patient is stabilized and hemorrhage has been definitively excluded. 1
Target INR of 2.5 to 3.5 for patients post-mitral valve repair, particularly given the thrombotic complication. 1
Add aspirin 81 to 100 mg daily to warfarin therapy, as this combination is strongly recommended after mitral valve procedures. 1
Continue anticoagulation for a minimum of 3 months, with consideration for longer duration given the stroke event. 1, 3
Common Pitfalls to Avoid
Do not delay CT imaging to pursue other diagnostics—hemorrhage exclusion is the absolute first priority and determines all subsequent management. 1
Do not use thrombolytic therapy in the immediate post-operative period, as randomized trials of intravenous streptokinase were stopped early due to unacceptable rates of intracranial hemorrhage. 1
Do not start heparin with a loading dose in this setting, as the patient's coagulation system is already disrupted from recent surgery. 1
Do not assume the stroke is thrombotic—air embolism must be considered and treated differently with hyperbaric oxygen if present. 2
Evidence Quality Considerations
The guidelines addressing cerebral embolism after valve procedures are primarily from the 1997 Consensus Conference on Prosthetic Valve Thrombosis 1, which remains the most specific guidance for this clinical scenario. More recent stroke guidelines from 2015 1 focus on endovascular therapy but are not applicable to immediate post-operative patients due to bleeding contraindications. The 2021 ACC/AHA guidelines 1 emphasize the increased stroke risk in the first 90-180 days post-valve surgery and support anticoagulation strategies. Recent research 3 demonstrates that anticoagulation after mitral valve repair reduces stroke/death risk by 72% at 3 months (HR 0.28) without excess bleeding, supporting aggressive anticoagulation in this population.