Page 2462 - Hematology_ Basic Principles and Practice ( PDFDrive )

2200 Part XII Hemostasis and Thrombosis

Treatment of Neonatal Thromboembolism Tissue Plasminogen Activator Thrombolysis for Neonatal
Thromboembolism
Unfractionated Heparin (UFH)
Bolus: 75 units/kg over 10 minutes Concurrent Heparin (UFH or Enoxaparin) Should Be Considered at
Maintenance: 28 units/kg/h; therapeutic goal, anti-FXa of 0.3 to Prophylactic Dosing; UFH Preferred
0.7 units/mL Life- or limb-threatening thrombi: starting dose of 0.1 to 0.5 mg/kg/h
Prophylaxis: 10 units/kg/h for up to 6 hours
Follow platelet count to detect possible HIT (risk is low) If no response, consider increase by 0.1 mg/kg/h increments to
maximum 0.5 mg/kg/h
Enoxaparin Consider using FFP 10 mL/kg before thrombolytic therapy
1.5 mg/kg subcutaneously every 12 hours (with normal renal Maintain fibrinogen greater than 100 mg/dL
function; round dose to nearest milligram; consider higher dose Maintain platelet count above 100 × 10 /L
9
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[see text] ) Reversal of severe bleeding with aminocaproic acid at 100 mg/kg
Check anti-FXa level by peripheral venipuncture 4 to 6 hours after intravenously every 6 hours
second or third dose; therapeutic goal, anti-FXa of 0.5 to 1 units/
mL (0.4 to 0.6 units/mL if concurrent thrombocytopenia or other FFP, Fresh frozen plasma; TE, thromboembolism; t-PA, tissue plasminogen
bleeding risk factor) activator; UFH, unfractionated heparin.
Follow platelet count to detect possible HIT (risk is low)
Hold for 24 hours before procedures
Prophylaxis With Enoxaparin Low-dose thrombolysis is recommended to open occluded catheters.
0.75 mg/kg subcutaneously every 12 hours t-PA is the drug that has been most widely studied in pediatric
If checked, anti-FXa level 4 to 6 hours after second or third dose patients. Transfusion support for hypofibrinogenemia and thrombo-
should be less than 0.4 units/mL cytopenia should be provided to minimize the bleeding risk. Contra-
Hold for 12 hours before procedures indications for thrombolytic therapy include active bleeding and
Purpura Fulminans major surgery or bleeding within the past 10 days, whereas relative
Concurrent heparin: UFH dose of 28 units/kg/h with target anti-FXa contraindications include severe asphyxia within 7 days, generalized
of 0.3 to 0.7 units/mL; LMWH dose of 1.0 to 1.5 mg/kg every seizures within the last 48 hours, sepsis, or prematurity of less than
12 hours with therapeutic target anti-FXa range of 0.5 to 1 units/ 32 weeks of gestation. If UFH or LMWH is given concomitantly
mL and replacement with FFP or protein C concentrate with t-PA, it should be administered at prophylactic doses (0.75 mg/
FFP: 10 to 20 mL/kg every 6 to 12 hours for purpura fulminans kg every 12 hours for LMWH or 10 units/kg/h for UFH; see box on
Protein C concentrate for severe protein C deficiency: load with t-PA Thrombolysis for Neonatal TE). Surgical thrombectomy is
100 to 120 units/kg, then 60 to 80 units/kg every 6 hours × reserved for organ-, limb-, or life-threatening thrombosis when t-PA
three doses (goal protein C activity 100%). Once therapeutic administration is impractical or predicted to be ineffective. Throm-
anticoagulation is achieved, maintenance therapy with 45 to bolytic therapy may be of benefit in a select group of pediatric
60 units/kg every 6 to 12 hours (goal protein C activity >25%).
patients with massive pulmonary embolism or extensive DVT.
Antithrombin Repletion
AT (functional) should be maintained at greater than 50% of normal
levels for effective heparin-based anticoagulation SUGGESTED READINGS
Dose in international units = (desired – current AT )
a
× weight (kg) Bhatt MD, Paes BA, Chan AK: How to use unfractionated heparin to treat
AT, Antithrombin; FFP, fresh frozen plasma; HIT, heparin-induced throm-
bocytopenia; LMWH, low-molecular-weight heparin; TE, thromboembolism; neonatal thrombosis in clinical practice. Blood Coagul Fibrinolysis 27:605,
UFH, unfractionated heparin. 2016.
Brandão LR, Simpson EA, Lau KK: Neonatal renal vein thrombosis. Semin
a Expressed as percentage of normal level based on functional AT level.
Fetal Neonatal Med 16:323, 2011.
Kenet G, Chan AK, Soucie JM, et al: Bleeding disorders in neonates. Hae-
mophilia 16:168, 2010.
Fondaparinux may be a reasonable option in selected cases, but Monagle P, Chan AK, Goldenberg NA, et al: Antithrombotic therapy in neo-
experience in neonates is limited. nates and children: antithrombotic therapy and prevention of thrombosis,
9th ed: American College of Chest Physicians Evidence-Based Clinical
Practice Guidelines [published errata appear in Chest. 2014;146:1422;
Thrombolytic Therapy and Chest. 2014;146:1694]. Chest 141(2 Suppl):e737S, 2012.
Williams S, Chan AK: Neonatal portal vein thrombosis: diagnosis and
Guidelines for thrombolytic management of neonatal TE are pro- management. Semin Fetal Neonatal Med 16:329, 2011.
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vided by the British Haemostasis and Thrombosis Task Force and
the Scientific Subcommittee on Perinatal and Pediatric Thrombosis
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of the International Society of Thrombosis and Haemostasis. Both REFERENCES
groups agree that thrombolysis should be considered for extensive TE
associated with organ dysfunction or limb-threatening ischemia. For the complete list of references, log on to www.expertconsult.com.