Fig. 34.2. Skin necrosis associated with an umbilical artery catheter. Such lesions develop after vasospasm or embolism. A: Spinal injury may be present when ischemia involves this region. B: The distal part

of an extremity is a common site for embolic arterial loss. The full extent of loss is unpredictable at this

stage. (From Fletcher MA. Physical Diagnosis in Neonatology. Philadelphia: Lippincott-Raven; 1998:127.)

Table 34.2 Laboratory Tests for Suspected Prothrombotic Disorders

Laboratory Test Collection Tube

Antiphospholipid antibody panel, anticardiolipin, lupus anticoagulant

(IgG, IgM)

Citrated plasma

Fibrinogen Citrated plasma

Protein C activity

Protein S activity

Antithrombin (activity assay)

Citrated plasma

Factor V Leiden

Prothrombin G

Methylenetetrahydrofolate reductase

Ethylenediaminetetraacetic acid

Homocysteine

Lipoprotein(a)

Citrated plasma

From Saxonhouse MA. Management of neonatal thrombosis. Clin Perinatol. 2012;39:191,with permission.

Chapter 34 ■ Management of Vascular Spasm and Thrombosis 227

c. Anticoagulation for at least 10 days; UFH or LMWH

is recommended for neonates with UAC-related

thrombosis.

d. If there are potentially life-, limb-, or organ-threatening signs in neonates with UAC-related thrombosis,

thrombolysis with rTPA should be considered.

e. If there are contraindications to thrombolysis, surgical thrombectomy may be indicated.

4. Anticoagulant/thrombolytic therapy

a. Contraindications

(1) Major surgery within the last 10 days

(2) Active or major bleeding: Intracranial, pulmonary, or gastrointestinal

(3) Preexisting cerebral ischemic lesions

(4) Seizures within 48 hours

(5) Relative contraindications (anticoagulant/

thrombolytic therapy may be given after correction of these abnormalities)

(a) Thrombocytopenia (platelet count <100 ×

109

/L)

(b) Hypofibrinogenemia (fibrinogen <100 mg/

dL)

(c) Severe coagulation factor deficiency

(d) Hypertension

b. Precautions

(1) No arterial punctures

(2) No subcutaneous or intramuscular injections

(3) No urinary catheterizations

(4) Avoid aspirin or other antiplatelet drugs.

(5) Monitor serial head ultrasound scans for intracranial hemorrhage.

c. Anticoagulants

(1) UFH

(a) Anticoagulant, antithrombotic effect limited by low plasma levels of antithrombin in

neonates.