Management of Right Atrial Thrombus (RAT)
Primary Recommendation by RAT Mechanism
For in-situ thrombus and catheter-associated thrombus without high-risk features or prohibitive bleeding risk, initiate systemic anticoagulation with target INR 2-3 as first-line therapy. 1 For clot-in-transit (Type A) with hemodynamic instability, proceed directly to systemic thrombolysis or surgical thrombectomy rather than anticoagulation alone. 1
Risk Stratification Framework
High-Risk Features Requiring Aggressive Intervention 1
- Thrombus characteristics: Large size (≥60 mm), snake-shaped or pedunculated morphology, high mobility 1, 2
- Anatomic involvement: Tricuspid valve involvement, blood flow restriction, or presence of intracardiac right-to-left shunt 1
- Clinical presentation: Hemodynamic compromise, arrhythmias, or associated pulmonary embolism 1, 3
- Device-related: Presence of central venous catheter or intracardiac leads 1
Bleeding Risk Assessment 1
- Active bleeding or recent hemorrhage (absolute contraindication to anticoagulation) 1
- Cirrhosis with coagulopathy 3
- Active malignancy with thrombocytopenia 3
- Recent intracranial hemorrhage or neurosurgery 1
Treatment Algorithm by Clinical Scenario
In-Situ Thrombus (Atrial Stasis)
Hemodynamically stable + low bleeding risk:
- Initiate therapeutic anticoagulation with unfractionated heparin bolus followed by continuous infusion (aPTT 1.5-2× control) 1
- Transition to oral anticoagulation (INR 2-3) for minimum 3-4 weeks, then reassess with repeat echocardiography 1
- For atrial fibrillation patients: Continue indefinite anticoagulation given stroke risk 1, 4
High bleeding risk:
- Conservative management with close monitoring may be considered only if thrombus lacks high-risk features 1
- Serial echocardiography every 48-72 hours to assess for thrombus progression 1
Catheter-Associated Thrombus
First-line approach:
- Remove catheter immediately AND initiate anticoagulation simultaneously 2, 5
- Obtain blood cultures to exclude infection before catheter removal 3, 5
- If infection confirmed (positive cultures), targeted antibiotic therapy for minimum 4-6 weeks 5
Anticoagulation regimen:
- Unfractionated heparin followed by warfarin (INR 2-3) for 3-6 months 2
- Mortality with catheter removal plus anticoagulation: 16.2% versus 13% with surgical thrombectomy (no significant difference) 2
Surgical thrombectomy indications:
- Thrombus ≥60 mm despite anticoagulation 2
- Failed anticoagulation therapy with thrombus progression 2
- Persistent sepsis despite catheter removal and antibiotics 2
Device-Related Thrombus (ICD/Pacemaker Leads)
Management sequence:
- Initiate anticoagulation (heparin → warfarin, INR 2-3) as first-line 1
- Do NOT remove device leads unless infection documented or thrombus causing hemodynamic compromise 1
- Consider percutaneous aspiration (e.g., AngioVac system) for large mobile thrombi if anticoagulation fails 1, 3
Clot-in-Transit (Type A) - HIGHEST MORTALITY RISK
Hemodynamically unstable (shock, severe hypoxemia):
- Immediate systemic thrombolysis (alteplase 100 mg over 2 hours) OR surgical embolectomy 1
- Do NOT delay for anticoagulation alone—mortality 80-100% without aggressive intervention 1, 6
- If thrombolysis contraindicated: Emergency surgical thrombectomy or catheter-directed thrombectomy (FlowTriever device) 6
Hemodynamically stable with confirmed pulmonary embolism:
- Systemic anticoagulation alone is insufficient 1
- Consider catheter-directed thrombectomy as bridge to anticoagulation 6
- Thrombolysis may be considered if no bleeding contraindications 1
Stable without pulmonary embolism:
- Anticoagulation alone may be attempted with intensive monitoring 1
- Low threshold for escalation to thrombolysis or thrombectomy if clinical deterioration 1
RAT with Absolute Contraindication to Anticoagulation
Active bleeding or recent hemorrhage:
- Catheter-directed mechanical thrombectomy (percutaneous aspiration) as first-line 6, 5
- Surgical thrombectomy if percutaneous approach unavailable or unsuccessful 1
- IVC filter placement to prevent paradoxical embolism if intracardiac shunt present 1
Supportive care only:
- Reserved for patients with prohibitive surgical risk AND contraindication to all interventions 1
- Serial imaging every 24-48 hours to monitor for complications 1
Critical Pitfalls to Avoid
Anticoagulation Errors
- Never use anticoagulation alone for clot-in-transit with hemodynamic instability—this approach has 80-100% mortality 1, 6
- Never interrupt anticoagulation prematurely in atrial fibrillation patients with RAT—embolic risk increases immediately 1
- Never delay heparin initiation when cardioversion planned for atrial fibrillation with suspected thrombus 1
Catheter Management
- Never leave catheter in place when catheter-associated thrombus diagnosed—mortality significantly higher without removal 2
- Always obtain blood cultures before catheter removal to guide antibiotic duration 5
Thrombolysis Timing
- Never administer thrombolysis without first confirming absence of intracranial hemorrhage, recent surgery, or active bleeding 1
- Never use thrombolysis as first-line for in-situ or catheter-associated thrombus—bleeding risk outweighs benefit 1, 2
Surgical Consultation
- Never delay surgical consultation for thrombus ≥60 mm or straddling interatrial septum 1, 2
- Never attempt percutaneous intervention without cardiac surgery backup available 6
Monitoring and Follow-Up
Acute Phase (First 72 Hours)
- Continuous telemetry monitoring for arrhythmias 1
- Serial echocardiography every 24-48 hours until thrombus resolution or stabilization 1, 2
- Daily assessment for pulmonary embolism symptoms (chest pain, dyspnea, hypoxemia) 1
Anticoagulation Monitoring
- aPTT every 6 hours during heparin infusion until therapeutic (1.5-2× control) 1
- INR weekly during warfarin initiation, then monthly when stable (target 2-3) 1
- For elderly patients >75 years with bleeding risk: Consider lower INR target 1.6-2.5 1