Management of Vascular Spasm and Thrombosis



Management of Vascular Spasm and Thrombosis


Matthew A. Saxonhouse

Ashley Hinson





A. Definitions

Within the pediatric population, neonates are at the highest risk for thrombosis. The combination of environmental and genetic prothrombotic risk factors significantly increases this risk. The use of arterial and central venous catheters represents the greatest risk for the development of thrombosis (1, 2). Although thrombosis can occur at several sites, this chapter focuses on catheter-related thrombosis. Recommendations for treatment of neonatal thrombosis are based on expert opinion and data from case series/studies. Care for neonates with significant thromboses should occur at a tertiary referral center that has appropriate subspecialty and laboratory support.

1. Prothrombotic disorder is the inheritance of a genetic mutation that results in the absence or severe deficiency of an inhibitor of hemostasis, the production of an inhibitor of hemostasis that has inadequate function despite normal levels, or an overproduction of a procoagulant protein or cofactor.

2. Vascular spasm is transient, reversible arterial constriction, often triggered by intravascular catheterization or arterial blood sampling.

3. Thrombosis is the complete or partial obstruction of arteries or veins by blood clot(s).

4. Anticoagulation is the process of administering an agent that hinders the clotting of blood.

5. Thrombolysis refers to the process of providing an agent that destroys or dissolves an active blood clot.


B. Assessment



1. Clinical Diagnosis

a. Risk factors associated with the development of neonatal thrombosis are presented in Table 36.1.

b. Neonatal thromboses may occur in a variety of locations and may present with varying signs and symptoms (Table 36.2).

c. Vascular spasm of peripheral arteries is characterized by transient pallor, or cyanosis of the involved extremity with diminished pulses and perfusion. The clinical effects of vascular spasm usually last <4 hours from the onset, but the condition may be difficult to differentiate from more serious thrombosis. The diagnosis of vasospasm of arteries is usually made retrospectively after documentation of the transient nature of ischemic changes and complete recovery of circulation (Figs. 36.1 and 36.2) (3).






FIGURE 36.1 Vasospasm following attempted radial artery catheterization in extremely preterm infant.









TABLE 36.1 Risk Factors for the Development of Neonatal Thromboses















MATERNAL RISK FACTORS

DELIVERY RISK FACTORS

NEONATAL RISK FACTORS


Infertility


Oligohydramnios


Prothrombotic disorder


Preeclampsia


Diabetes


Intrauterine growth restriction


Chorioamnionitis


Prolonged rupture of membranes


Autoimmune disorders

Emergent cesarean section


Fetal heart rate abnormalities


Instrumentation


Meconium-stained fluid

Central venous/arterial cathetersa


Congenital heart disease


Sepsis


Meningitis


Birth asphyxia


Respiratory distress syndrome


Dehydration


Congenital nephritic/nephrotic syndrome


Necrotizing enterocolitis


Polycythemia


Pulmonary hypertension


Surgery


Extracorporeal membrane oxygenation


Medications (steroids)


a Greatest risk factor for thrombosis.


From Saxonhouse MA, Manco-Johnson MJ. The evaluation and management of neonatal coagulation disorders. Semin Perinatol. 2009;33:56; and Data from (1, 11, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36).









TABLE 36.2 Locations of Neonatal Thromboses and the Best Imaging Modalities to Diagnose Them































VESSEL

TYPE OF THROMBOSES (VESSELS POTENTIALLY INVOLVED)

IMAGING MODALITY


Arterial

Perinatal arterial ischemic stroke


(left middle cerebral artery, anterior cerebral artery, posterior cerebral artery)

Diffusion-weighted MRI/MRA


Iatrogenic


(abdominal aorta, radial artery, renal artery, mesenteric artery, popliteal artery)

Doppler ultrasound


Spontaneous


(iliac artery, left pulmonary artery, aortic arch, descending aorta, renal artery)


Venous

Iatrogenic/spontaneous vessel occlusion


(SVC, IVC, hepatic vein, subclavian vein, abdominal veins, peripheral veins)


Renal vein


Portal vein


Cerebral sinovenous


(superior sagittal sinus, transverse sinuses of the superficial venous system, straight sinus of the deep system)

Diffusion-weighted MRI w/venography


Congenital heart disease related


(right/left atria, right/left ventricle, superior vena cava, inferior vena cava)

Echocardiography


Adapted from Saxonhouse MA. Management of neonatal thrombosis. Clin Perinatol. 2012;39:192-193; and Data from (4, 35-40).








FIGURE 36.2 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. (Reprinted with permission from Fletcher MA. Physical Diagnosis in Neonatology. 1st ed. Philadelphia, PA: Lippincott-Raven; 1998:127.)

d. Persistent bacteremia, thrombocytopenia, and/or central line dysfunction are nonspecific signs associated with vascular thrombosis at any site (4).

e. Clinical signs may be subtle or absent in many cases of thrombosis, which may be detected incidentally during ultrasonography for other indications.


2. Diagnostic Imaging

a. Optimal diagnostic modalities for diagnosing neonatal thromboses are presented in Table 36.2.

b. Contrast angiography: Gold standard; gives best definition of thrombosis but is difficult to perform in critically ill neonates; requires infusion of radiocontrast material that may be hypertonic or cause undesired increase in vascular volume (5).

c. Doppler ultrasonography: Portable, noninvasive monitors improve over time, but may give both false-positive and false-negative results compared with contrast angiography (6).


3. Additional Diagnostic Tests

a. Obtain detailed family history in all cases of vascular thrombosis.

b. Prothrombotic disorders increase a neonate’s risk for developing pathologic thrombosis. It is recommended that neonates with significant thrombosis (other than asymptomatic central venous line thrombosis) be tested for genetic prothrombotic traits based on the presence of other risk factors (Table 36.3) (7).

c. Laboratory evaluation should take place at an experienced tertiary care center that has either self-laboratory support or a reliable referral center. This approach can dramatically reduce the amount of blood required for this testing (2).

d. Due to many of the pro/anticoagulation protein levels being lower than adult values, the diagnosis of a prothrombotic disorder may be difficult to confirm in the immediate neonatal period. If abnormal values are obtained in the immediate neonatal period, these should be repeated at 3 to 6 months of age.

e. Lipoprotein(a) concentrations increase during the first year of life and should be repeated at 8 to 12 months of life if values obtained at 3 to 6 months are low, especially in Caucasian individuals.

f. DNA-based assays (see Table 36.3) are accurate during the neonatal period and may be obtained at any time.

g. The different evaluations presented (see Table 36.3) are based on the presence of acquired risk factors, type of thrombosis, severity of thrombosis, and treatment regimen.

h. Baseline complete blood count (CBC), prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen levels should be obtained shortly after the acute event.

i. Placental pathology, especially in cases of ischemic perinatal stroke, should be requested (8).


C. Management of Arterial Vascular Spasm/Thromboses


1. Arterial Vascular Spasm

a. A stepwise approach to the management of vascular spasm is presented in Figure 36.3.









TABLE 36.3 Laboratory Evaluation for Prothrombotic Disorder













LABORATORY TESTING IF OTHER ACQUIRED RISK FACTORS PRESENT

LABORATORY TESTING IF OTHER ACQUIRED RISK FACTORS NOT PRESENT


▪ Antiphospholipid antibody panel, anticardiolipin and lupus anticoagulant (IgG, IgM)a


▪ Protein C activityb


▪ Protein S activityb


▪ Lipoprotein(a) (in Caucasian neonates)b


▪ Plasminogen levelb (if considering thrombolytic therapy)


▪ Antithrombin III (AT-III) (activity assay)b


▪ Factor V Leidenc


▪ Factor II G20210A (prothrombin G)c

▪ Antiphospholipid antibody panel, anticardiolipin and lupus anticoagulant (IgG, IgM)a


▪ Protein C activityb


▪ Protein S activityb


▪ Antithrombin (activity assay)b


▪ Factor V Leidenc


▪ Prothrombin Gc


▪ PAI-1 4G/5G mutationc


▪ Homocysteineb (if elevated, screen for methylenetetrahydrofolate reductase gene mutation)


▪ Lipoprotein(a)b


▪ Factor VIII activityb


▪ Factor XII activityb


▪ Plasminogen activityb


▪ Heparin cofactor IIb


a May be performed from maternal serum during first few months of life.

b Protein-based assays are affected by the acute thrombosis and must be repeated at 3-6 months of life, before a definitive diagnosis may be made. Therefore, recommend that complete evaluation (excluding DNA-based assays) be performed at 3-6 months of life (21). If anticoagulation is being administered, then these assays should be obtained 14-30 days after discontinuing the anticoagulant. Lipoprotein(a) levels may need to be repeated at 8-12 months of life.

c DNA-based assays.


Adapted from Saxonhouse MA, Manco-Johnson MJ. The evaluation and management of neonatal coagulation disorders. Semin Perinatol. 2009;33:59; and Data from (16, 27, 28, 32, 41, 42).

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Dec 15, 2019 | Posted by in PEDIATRICS | Comments Off on Management of Vascular Spasm and Thrombosis

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