Anticoagulation for Sickle Cell Crisis with Pulmonary Embolism
For a patient with sickle cell disease experiencing a crisis and diagnosed with pulmonary embolism, initiate therapeutic anticoagulation with enoxaparin (Lovenox) 1 mg/kg subcutaneously twice daily, as low-molecular-weight heparin is the preferred parenteral anticoagulant for PE in hemodynamically stable patients. 1
Acute Phase Management
Initial Anticoagulation Strategy
Prefer LMWH (enoxaparin/Lovenox) or fondaparinux over unfractionated heparin for patients without hemodynamic instability, which applies to most sickle cell crisis presentations with PE 1
Enoxaparin dosing for PE treatment: 1 mg/kg subcutaneously twice daily, or alternatively 1.5 mg/kg once daily (approved in the US for inpatient treatment) 1
Initiate anticoagulation immediately upon high or intermediate clinical probability of PE while diagnostic workup proceeds, unless active bleeding or absolute contraindications exist 2
Hemodynamic Considerations
Stratify the patient based on hemodynamic stability to determine risk category and treatment intensity 1
Reserve unfractionated heparin for patients being considered for primary reperfusion therapy, those with severe renal impairment (creatinine clearance <30 mL/min), or severe obesity 1
Do not routinely administer systemic thrombolysis as primary treatment in intermediate- or low-risk PE, even in sickle cell patients 1
Transition to Oral Anticoagulation
NOAC vs VKA Selection
When transitioning to oral anticoagulation, prefer a NOAC (apixaban, dabigatran, edoxaban, or rivaroxaban) over vitamin K antagonists for eligible patients 1
Consider renal function carefully in sickle cell patients: Avoid edoxaban if creatinine clearance >95 mL/min due to decreased efficacy; do not use NOACs with severe renal impairment 1
As an alternative to NOACs, use a VKA (warfarin), overlapping with parenteral anticoagulation for at least 5 days and until INR reaches 2.0-3.0 for two consecutive days 1
Duration of Anticoagulation in Sickle Cell Disease
Special Considerations for SCD
Sickle cell disease is considered a chronic underlying risk factor for initial and recurrent VTE, which influences duration decisions 1
For first provoked VTE (such as during a vaso-occlusive crisis): Suggest defined periods of anticoagulation (3-6 months) over indefinite anticoagulation 1
For recurrent provoked VTE: Suggest indefinite anticoagulation over shorter defined periods 1
All patients with PE require therapeutic anticoagulation for >3 months as a minimum baseline 1
Critical Decision Points
The sickle cell crisis itself may be considered a provoking factor, but the type and strength of the provoking event should guide duration decisions through shared decision-making 1
Reassess drug tolerance, adherence, hepatic and renal function, and bleeding risk at regular intervals in patients receiving extended anticoagulation 1
Consider bleeding risk from concurrent medications (such as NSAIDs commonly used for pain management in sickle cell crisis) when determining anticoagulation duration 1
Important Caveats
PE diagnosis in sickle cell patients is challenging because presenting symptoms often mimic vaso-occlusive crisis; the Wells score >4 has 72.5% sensitivity and 70.1% specificity for PE in this population 3
Anticoagulation should continue as long as any provoking risk factor persists, including central venous lines commonly present in sickle cell patients 1
Enoxaparin monotherapy without oral anticoagulation is feasible for extended treatment periods (up to 90 days) if oral anticoagulation is problematic, though this requires further validation 4