When should I stop an unfractionated heparin infusion before performing a transesophageal echocardiogram (TEE) in an adult patient on a therapeutic heparin drip for atrial fibrillation, pulmonary embolism, or deep vein thrombosis?

Heparin Management Before TEE

You do not need to stop a therapeutic unfractionated heparin (UFH) infusion before performing a transesophageal echocardiogram (TEE). TEE can be safely performed while the patient remains on continuous IV heparin anticoagulation.

Evidence-Based Rationale

TEE-Guided Cardioversion Protocol with Concurrent Heparin

The established approach for TEE-guided cardioversion explicitly includes maintaining therapeutic anticoagulation during the procedure:

• LMWH at full VTE treatment doses or IV UFH should be started at the time of TEE, with the target being an aPTT prolongation corresponding to plasma heparin levels of 0.3-0.7 IU/mL anti-factor Xa activity 1
• Cardioversion is performed within 24 hours of the TEE if no thrombus is identified, while anticoagulation continues 1
• For patients requiring immediate cardioversion due to hemodynamic instability, heparin should be administered concurrently by initial IV bolus followed by continuous infusion adjusted to prolong aPTT to 1.5-2 times control 1

Safety Data in High-Risk Patients

Recent evidence demonstrates TEE safety even in patients with significant coagulopathy:

• A single-center study of 228 TEEs performed by intensivists and emergency physicians found no difference in complications between high bleeding risk patients (including those on therapeutic anticoagulation with aPTT >40 seconds) versus low-risk patients 2
• Upper esophageal bleeding occurred in only 4% of high-risk patients versus 1% of low-risk patients (not statistically significant), with no deaths attributable to TEE in either group 2

Practical Management Algorithm

For Patients Already on Therapeutic UFH:

1. Verify therapeutic anticoagulation: Check that aPTT is 1.5-2.5 times control (typically 55-85 seconds) or corresponds to anti-Xa levels of 0.3-0.7 IU/mL 1
2. Continue the heparin infusion without interruption during TEE 1
3. Maintain continuous infusion throughout the procedure and afterward 1

For Patients Not Yet Anticoagulated:

1. Initiate UFH immediately with IV bolus (typically 5000-10,000 units) followed by continuous infusion 1
2. Target aPTT of 1.5-2 times control (corresponding to 0.3-0.7 IU/mL anti-Xa activity) 1
3. Perform TEE once therapeutic anticoagulation is achieved 1

Critical Considerations

Timing Nuances

The guidelines consistently emphasize that anticoagulation should be present at the time of TEE, not withheld before it 1. This approach:

• Prevents thrombus formation during the procedure
• Allows immediate cardioversion if no thrombus is visualized
• Maintains protection against thromboembolism throughout the peri-procedural period

Common Pitfall to Avoid

Do not confuse TEE with other invasive procedures that require heparin discontinuation (such as kidney biopsy, which requires 4-6 hours off heparin) 3. TEE is fundamentally different because:

• It is performed specifically to assess for thrombus before cardioversion
• The patient requires anticoagulation for the underlying condition (AF, PE, DVT)
• The bleeding risk from TEE probe insertion is minimal even with therapeutic anticoagulation 2

Post-TEE Management

• Continue therapeutic anticoagulation for at least 4 weeks after successful cardioversion regardless of baseline stroke risk 1
• Long-term anticoagulation decisions should be based on thromboembolic risk factors, not on apparent cardioversion success 1
• If thrombus is identified on TEE, postpone cardioversion and continue anticoagulation for 3-4 weeks before considering repeat imaging 1