h. Anticoagulation therapy with unfractionated heparin (UFH) or low-molecular-weight heparin

(LMWH) is used for clinically significant clots with

the goal of preventing clot extension or embolization.

i. Recombinant tissue plasminogen activator (rTPA) is

reserved for thrombolysis of severe life-, organ-, or

limb-threatening thrombosis.

j. The International Children’s Thrombophilia

Network, which is based in Canada, is a free

consultative service, maintained 24 hours a day, for

Fig. 34.1. Vasospasm following attempted radial artery catheterization in extremely preterm infant.

Table 34.1 Diagnosis of Vascular Thrombosis

Site Clinical Signs Diagnostic Imaging

CVL-associated venous thrombosis Malfunction of CVL, SVC syndrome, chylothorax, swelling and

livid discoloration of extremity, dilatation of collateral veins

over trunk or abdomen in chronic cases

Inferior vena cava thrombosis Lower limbs cool, cyanotic, edematous Contrast angiography

Doppler ultrasonography

Real-time 2D ultrasonography

Superior vena cava thrombosis

Renal vein thrombosis

Swelling of upper limbs and head, chylothorax

Flank mass, hematuria, thrombocytopenia, hypertension

Aortic or renal arterial thrombosis Systemic hypertension, hematuria, oliguria

Peripheral or central (aorta or iliac) arterial

thrombosis

Pallor, coldness, weak or absent peripheral pulse(s),

discoloration, gangrene

Right atrial thrombosis Congestive heart failure Echocardiography

Pulmonary thromboembolism Respiratory failure Lung perfusion scan

CVL, central venous line; SVC, superior vena cava.

}

226 Section V ■ Vascular Access

physicians worldwide who are caring for children

with thromboembolic disease. The toll-free number

in the North America is 1-800-NO-CLOTS; the

number for physicians elsewhere is 1-905-573-4795

(Web site http://www.1800noclots.ca/) The service

provides current management protocols as well as

links to the network and its services.

2. Management of catheter-related venous

thrombosis (12)

a. Either initial anticoagulation or supportive care

with radiological monitoring may be appropriate.

However, anticoagulation is recommended if extension of the thrombus occurs during supportive care.

b. Remove central venous lines (CVL) or umbilical

venous lines associated with confirmed thrombosis, preferably after 3 to 5 days of anticoagulation.

This recommendation has been made to reduce

the risk of paradoxical emboli at the time of CVL

removal.

c. Intravascular catheters are occasionally left in place

if local thrombolysis through the catheter is planned

(14).

d. Anticoagulation may be with LMWH or UFH for 3

to 5 days followed by LMWH.

e. Total duration of anticoagulation is between 6 and

12 weeks.

f. Thrombolytic therapy is not recommended for neonatal venous thrombosis unless major vessel occlusion is causing critical compromise of organs or limbs.

3. Management of arterial thrombosis (12)

a. Initiate management as for vasospasm if there are

peripheral signs of ischemia.

b. Remove catheter unless catheter-directed thrombolysis is planned (14)

A B