How should I manage a patient with a previously replaced mitral valve who now has a stuck prosthetic valve, including diagnostic steps, medical therapy, and indications for redo mitral valve replacement?

Management of Stuck Prosthetic Mitral Valve Requiring Redo Surgery

Emergency surgical valve replacement is the definitive treatment for a stuck mechanical mitral valve causing NYHA class III-IV symptoms, as this approach minimizes risks of thromboembolism, major bleeding, and recurrent valve dysfunction compared to thrombolytic therapy. 1

Immediate Diagnostic Workup

Clinical Assessment

• Evaluate for recent onset dyspnea, fatigue, or heart failure symptoms developing over days to weeks 1, 2
• Determine anticoagulation history—subtherapeutic INR or interrupted warfarin in preceding weeks strongly suggests thrombosis 1, 2, 3
• Check for precipitating factors: dehydration, infection, or other hypercoagulable states 1

Imaging Protocol

• Transthoracic echocardiography (TTE) first to assess hemodynamic severity, transvalvular gradients, and ventricular function 1
• Transesophageal echocardiography (TEE) is essential to visualize clot burden, assess leaflet motion, and differentiate thrombus from pannus 1
• Fluoroscopy or cardiac CT to directly visualize mechanical leaflet motion and confirm obstruction 1, 4
• Note: Thrombus appears as soft, mobile echogenic mass while pannus is fixed fibrous tissue, though both frequently coexist 2, 5, 3

Laboratory Studies

• INR, complete blood count (assess for hemolytic anemia from paravalvular leak), lactate dehydrogenase, blood cultures to exclude endocarditis 1

Initial Stabilization

Upon diagnosis confirmation, immediately:

• Administer 5000 units intravenous unfractionated heparin 1
• Transfer urgently to cardiac surgical center 1
• Avoid vitamin K if INR >6.0 due to rapid reversal risking further thrombosis; instead use fresh-frozen plasma if INR >10.0 1

Treatment Algorithm Based on Clinical Status

NYHA Class III-IV or Cardiogenic Shock

Emergency surgery is Class I recommendation 1, 6

• Redo mitral valve replacement is preferred over attempting repair when valve is stuck 6
• Operative mortality for redo mitral surgery ranges 4.7-17.5%, but this is lower than thrombolysis risks in critically ill patients 6
• Intraoperative findings typically reveal combined thrombus and pannus requiring complete valve replacement 2, 5, 3

NYHA Class I-II with Small Clot Burden (<0.8 cm²)

Fibrinolytic therapy is reasonable (Class IIa) if recent onset (<14 days) 1

• Slow-infusion, low-dose thrombolytics show favorable outcomes when surgery unavailable or prohibitive risk 2, 4
• However, fibrinolysis carries 12-15% risk of cerebral emboli and is often ineffective for pannus 1
• Alternative: Intravenous unfractionated heparin may be considered (Class IIb) 1

Large or Mobile Thrombus (>0.8 cm²)

Emergency surgery is reasonable (Class IIa) regardless of symptom severity due to high embolic risk 1

Preoperative Risk Stratification for Redo Surgery

Critical assessments before reoperation:

• Right heart catheterization to measure pulmonary artery pressures—elevated pressures significantly increase operative mortality (Class I recommendation) 6
• Echocardiographic estimates alone are insufficient for high-risk reoperative cases 6
• Assess for concurrent left atrial appendage thrombus on TEE, which complicates surgical planning 2

Surgical Options at Reoperation

Primary Approach

• Complete mechanical valve replacement is most frequently performed for stuck valves 6
• Indicated when defect is large, irregular, multiple, or when pannus extensively involves the prosthesis 6, 5

Alternative Approach

• Direct surgical repair of paravalvular defect while preserving existing valve is possible if obstruction is localized 6
• Choice depends on intraoperative findings of thrombus versus pannus burden and defect characteristics 6

Percutaneous Option for High-Risk Patients

Percutaneous closure of paravalvular leak is Class IIa recommendation for patients at prohibitive surgical risk with suitable anatomy 1, 6

• Technical success rates 80-85% with procedural mortality <2% 6
• Best suited for hemolysis from paravalvular leak rather than obstructive thrombosis 6
• Transcatheter manipulation of stuck leaflet is emerging option as bridge to surgery 4

Critical Pitfalls to Avoid

• Do not delay surgery in NYHA III-IV patients attempting medical therapy—clinical deterioration can be rapid and catastrophic 1, 2, 3
• Do not assume thrombus alone based on imaging; pannus and thrombus coexist in majority of stuck mechanical valves 2, 5, 3
• Do not use thrombolysis as first-line for left-sided mechanical valve thrombosis with severe symptoms due to high embolic risk 1, 4
• Do not rely on physical examination alone—severe paravalvular regurgitation may be inaudible 1

Post-Surgical Management

• Baseline TTE at 2-4 weeks post-discharge to establish new prosthesis hemodynamics 1
• Resume therapeutic anticoagulation with unfractionated heparin bridge to warfarin, targeting INR 2.5-3.0 for mechanical mitral valve 1
• Annual follow-up with earlier re-evaluation if clinical status changes 1