Immediate Management of Intraoperative Massive Watershed Stroke During Mitral Valve Repair
Immediately obtain non-contrast head CT to differentiate ischemic from hemorrhagic stroke, as this single determination dictates all subsequent anticoagulation decisions and is the most critical step in acute management. 1
Initial Diagnostic and Assessment Steps
Perform rapid neurological examination documenting specific deficits including motor function, sensory changes, speech abnormalities, and visual field defects to establish baseline stroke severity and guide prognostication 1. This documentation is essential for medicolegal purposes and tracking progression.
Obtain coagulation parameters immediately including PT/INR, aPTT, platelet count, and complete blood count, as these results determine reversal strategies and bleeding risk 1.
Obtain brain MRI with diffusion-weighted imaging (DWI) as soon as clinically feasible, since standard CT scans miss 42-100% of acute ischemic strokes within the first 6-24 hours, particularly small embolic watershed events 2. This is critical because attributing neurological deficits to "post-operative delirium" without excluding stroke via MRI represents a significant diagnostic pitfall 2.
Immediate Hemodynamic Management
Maintain cerebral perfusion pressure >70 mmHg using vasopressors if necessary, as hypotension extends ischemic injury in watershed territories that are already critically hypoperfused 1. This is particularly crucial in watershed strokes where perfusion pressure is the primary determinant of tissue survival.
Keep head of bed elevated 30 degrees to reduce intracranial pressure while maintaining adequate cerebral perfusion 1.
Maintain normoglycemia (glucose 140-180 mg/dL) as hyperglycemia significantly worsens stroke outcomes through multiple mechanisms including increased oxidative stress and blood-brain barrier disruption 1.
Critical Anticoagulation Decision Algorithm
If Hemorrhagic Stroke on CT:
Immediately reverse all anticoagulation with prothrombin complex concentrate and vitamin K, accepting the risk of prosthetic valve thrombosis as secondary to preventing hemorrhage expansion 1. The mortality from expanding intracranial hemorrhage exceeds the risk of acute valve thrombosis in this scenario.
If Ischemic Stroke on CT:
Continue therapeutic anticoagulation with unfractionated heparin (aPTT 1.5-2.0 times control) to prevent thrombus propagation and recurrent embolism 1. This represents a critical divergence from standard stroke protocols where anticoagulation is typically delayed.
Initiate oral anticoagulation (warfarin INR 2.0-3.0) for minimum 3 months post-mitral valve repair, as this reduces stroke risk by 72% (HR 0.28) without increasing major bleeding 1, 3. This recommendation applies even in patients without atrial fibrillation or other traditional indications.
Massive Stroke-Specific Interventions
Transfer immediately to a center with neurosurgical expertise if not already at such a facility, as patients with massive cerebral infarction at risk of malignant swelling require rapid access to decompressive procedures 4.
Perform serial physical examinations and repeat head CT scans to identify worsening brain swelling, as watershed strokes can evolve into malignant edema requiring surgical intervention 4.
Immediately intubate if neurological deterioration with respiratory insufficiency develops, as airway protection and controlled ventilation are essential for maintaining cerebral oxygenation 4.
Consider decompressive hemicraniectomy within 48 hours if massive hemispheric infarction with worsening neurological condition develops, particularly in patients <60 years where functional benefit is substantially greater 4.
Mechanism-Specific Considerations
Evaluate for air embolism as the primary cause, since inadequate de-airing technique during mitral valve repair is a well-documented stroke mechanism 1, 2. Review intraoperative TEE images for evidence of retained intracardiac air.
Assess for aortic atherosclerotic disease that may have been disrupted during cannulation, as this represents another common embolic source during cardiac surgery 1.
Consider incomplete left atrial appendage management if this was part of the procedure, as residual peridevice leak occurs in 26-57% of cases and increases thromboembolism risk 2.
Post-Procedure Monitoring Protocol
Admit to intensive care unit with continuous cardiac monitoring for at least 24 hours to screen for atrial fibrillation and other arrhythmias that increase stroke risk 4.
Maintain blood pressure below 180/105 mmHg for at least the first 24 hours if reperfusion therapy is considered, though this must be balanced against maintaining cerebral perfusion pressure >70 mmHg 4.
Monitor body temperature and treat fever (>38°C) aggressively, as hyperthermia worsens neurological outcomes 4.
Use antiseizure medications only for documented secondary seizures, not prophylactically, as prophylactic use does not improve outcomes and adds medication risks 4.
Multidisciplinary Team Activation
Immediately involve neurology, cardiac surgery, and critical care in shared decision-making regarding ongoing cardiac surgical management and stroke treatment 4. The decision to complete or abort the mitral valve repair depends on the severity of both cardiac pathology and neurological injury.
Engage family in shared decision-making regarding anticipated prognosis for functional recovery, as massive stroke during cardiac surgery carries substantial mortality and morbidity risk 4.
Common Pitfalls to Avoid
Do not delay CT imaging to "finish the case" if intraoperative stroke is suspected, as the hemorrhagic versus ischemic distinction must be made before any anticoagulation decisions 1.
Do not assume sinus rhythm eliminates stroke risk, as 80% of patients with preoperative atrial fibrillation ≥3 months maintain atrial fibrillation postoperatively despite concomitant Maze procedure 2, 5.
Do not attribute neurological changes to anesthesia emergence without imaging confirmation, as this delay worsens outcomes 2.
Do not withhold anticoagulation in ischemic stroke due to fear of hemorrhagic conversion, as the risk of recurrent embolism exceeds hemorrhagic transformation risk in this population 1.
Prognostic Considerations
Perioperative stroke is the strongest independent risk factor for postoperative mortality (OR 2.34) and morbidity (OR 4.53) after mitral valve surgery 6. This information is essential for informed consent discussions with family regarding realistic outcome expectations.
Age is the only consistent independent predictor of stroke occurrence across multiple studies, with each decade increasing risk 7. Patients >75 years have substantially worse outcomes.
In-hospital mortality after mitral valve surgery with perioperative stroke approaches 5.5% with overall morbidity of 63.3%, representing a devastating complication 6.