What is the recommended heparin bolus dose for a patient with severe mitral stenosis undergoing bridging with Acitrom (Acenocoumarol)?

Heparin Bolus Dose for Bridging with Acitrom in Severe Mitral Stenosis

For patients with severe mitral stenosis undergoing bridging with Acitrom (acenocoumarol), an initial intravenous heparin bolus of 80-100 units/kg should be administered, followed by continuous infusion to maintain APTT at 1.5-2 times normal. 1

Rationale for Heparin Dosing in Mitral Stenosis

Patients with severe mitral stenosis require careful anticoagulation management due to their high thromboembolic risk. When bridging from Acitrom (acenocoumarol), therapeutic anticoagulation is crucial to prevent potentially fatal thromboembolic events.

Dosing Protocol:

1. Initial bolus: 80-100 units/kg IV 1, 2
2. Maintenance infusion: 20,000-40,000 units/24 hours via continuous IV infusion 3, 2
3. Target APTT: 1.5-2 times normal (equivalent to anti-factor Xa level of 0.3-0.7 U/mL) 3, 1

Special Considerations for Mitral Stenosis

Mitral stenosis presents unique challenges during anticoagulation bridging:

• Heart rate control is particularly important in mitral stenosis during the bridging period 3
• Patients with severe mitral stenosis are at high risk for thromboembolism, especially with atrial fibrillation 3, 1
• Therapeutic anticoagulation is extremely important to avoid complications in these high-risk patients 3

Monitoring Recommendations

Close monitoring is essential during heparin bridging:

• Check APTT every 4-6 hours during initial therapy 2
• Adjust dose to maintain APTT at 1.5-2 times normal 3, 1
• Monitor platelet counts regularly to detect heparin-induced thrombocytopenia 2
• Continue heparin until INR reaches therapeutic range with resumed Acitrom 1

Important Precautions

• Avoid intramuscular injections during heparin therapy due to bleeding risk 2
• Be vigilant for signs of bleeding complications, which occur more frequently with higher heparin doses 3, 1
• For patients with mechanical heart valves (which may coexist with mitral stenosis), therapeutic anticoagulation is particularly critical 3

Resuming Acitrom

• Resume Acitrom (acenocoumarol) on the evening of or day after any procedure 1
• Continue heparin infusion until INR reaches therapeutic range (typically 2.0-3.0 for most indications, may be higher for mechanical valves) 1, 4
• For patients with mitral stenosis, target INR should be maintained at 2.0-3.0 4

This protocol balances the need for effective anticoagulation in high-risk mitral stenosis patients while minimizing bleeding complications during the bridging period with Acitrom.