Persistent Embolic Risk Despite TEE-Confirmed Complete Transaortic Left Ventricular Thrombectomy During Coronary Artery Bypass Grafting: Recurrent Systemic Embolization in Severe Ischemic Cardiomyopathy

Technical Summary: Persistent Embolic Risk Despite TEE-Confirmed Complete Transaortic Left Ventricular Thrombectomy

Problem Statement
Left ventricular thrombus (LVT) is a critical complication of acute myocardial infarction, particularly in patients with apical akinesia and severe systolic dysfunction. While systemic anticoagulation is the standard of care, recurrent systemic embolization can occur despite therapeutic levels, creating a management dilemma for patients who also require urgent coronary revascularization. Although surgical thrombectomy during coronary artery bypass grafting (CABG) is an option for large or mobile thrombi, the literature lacks detailed accounts of major postoperative embolic complications occurring even after technically successful, imaging-confirmed thrombus removal. This case addresses the gap in understanding the residual thromboembolic risk in patients with severe ischemic cardiomyopathy and recent recurrent embolization, challenging the assumption that surgical clearance equates to risk elimination.

Methodology and Case Presentation
The authors present a single-case report of a 57-year-old male with severe ischemic cardiomyopathy (LVEF 25–30%), triple-vessel coronary artery disease with left main involvement, and a large (33 × 24 mm) mobile apical LVT. The patient experienced recurrent systemic embolization manifesting as acute left upper-limb ischemia and a small cerebral infarction.

The management strategy involved a hybrid surgical approach:

1. Preoperative Stabilization: Emergency brachial embolectomy was performed, followed by unfractionated heparin therapy with strict activated partial thromboplastin time (aPTT) monitoring (60–80 seconds).
2. Surgical Intervention: The patient underwent urgent hybrid CABG. This included off-pump left internal mammary artery (LIMA) to left anterior descending (LAD) grafting to minimize ventricular manipulation, followed by on-pump saphenous vein grafting to the obtuse marginal and posterior descending arteries.
3. Thrombectomy and Exclusion: A transaortic approach was utilized for direct visualization and complete removal of the apical thrombus. Intraoperative transesophageal echocardiography (TEE) confirmed complete thrombus removal, persistent apical akinesia, and an LVEF of ~25%. The left atrial appendage (LAA) was surgically ligated.
4. Postoperative Management: Anticoagulation was resumed early (4 hours post-op), and dual antiplatelet therapy was restarted once bleeding risk subsided.

Key Results
Despite the comprehensive surgical and medical management, the patient suffered a major postoperative neurological event:

• Clinical Outcome: Immediately post-surgery, the patient developed dense left hemiplegia.
• Imaging Findings: Non-contrast CT revealed a large right middle cerebral artery (MCA) territory infarction with significant cerebral edema, midline shift, and a concomitant right cerebellar infarction. Serial scans confirmed non-hemorrhagic infarction.
• Mechanism: The multifocal distribution of infarcts (MCA and cerebellar) was deemed suggestive of an embolic mechanism.
• Recovery: The patient required prolonged ventilatory support, tracheostomy, and neurorehabilitation, with persistent left-sided weakness at discharge.

Key Contributions
This case report contributes to the existing literature by:

• Documenting a scenario where TEE-confirmed complete thrombus removal and surgical LAA exclusion failed to prevent a major embolic stroke.
• Highlighting that technical success in thrombectomy does not necessarily correlate with the elimination of thromboembolic risk in patients with severe ventricular dysfunction and recent recurrent embolization.
• Providing a detailed timeline of perioperative antithrombotic management and intraoperative verification, offering a counterpoint to literature that primarily focuses on the technical feasibility of thrombectomy without addressing subsequent catastrophic embolic events.

Significance and Claims
The authors assert that this case demonstrates that patients with severe ischemic cardiomyopathy, large mobile LVTs, and recent recurrent systemic embolization represent an ultra-high-risk subgroup. The primary significance of the work is the cautionary finding that residual embolic risk persists even after:

1. Preoperative therapeutic anticoagulation.
2. Intraoperative confirmation of complete thrombus clearance via TEE.
3. Surgical exclusion of the left atrial appendage.
4. Early postoperative resumption of anticoagulation.

The paper concludes that the "technical success" of a thrombectomy should not be equated with the "elimination" of embolic risk. Consequently, surgeons and multidisciplinary Heart Teams must maintain vigilance, counsel families regarding this persistent residual risk, and recognize that postoperative stroke may occur despite adherence to accepted surgical and medical strategies. The authors suggest that for such high-risk patients, alternative strategies (e.g., intensified preoperative anticoagulation with imaging surveillance, staged procedures, or mechanical circulatory support) warrant further investigation, though they do not propose a definitive new protocol.