Pediatric Idiopathic Pulmonary Artery Hypertension Workup

The diagnostic assessment in idiopathic pulmonary artery hypertension (IPAH) includes a variety of blood studies, coagulation studies, tests for collagen-vascular disease, and imaging studies, as well as a variety of other tests and procedures.

For more information, see the Medscape Reference articles Primary Pulmonary Hypertension and Persistent Newborn Pulmonary Hypertension.

The following blood studies are indicated in the evaluation of IPAH:

• Complete blood count with differential

• Liver function tests

• Serum viscosity

• Serum protein electrophoresis

• Hemoglobin electrophoresis

• Quantitative immunoglobulins

• Fractionated plasma catecholamine

• HIV test

• Thyroid function tests

Coagulation studies include the following:

• Coagulation profile

• Bleeding time

• Platelet aggregation studies

• Coagulation factors (eg, factor VIII, von Willebrand factors, antithrombin III, protein S, protein C, factor VII, factor II, factor V)

In addition, consider an evaluation for homocystinemia as well as for defects in the promoter in prothrombin gene (ie, prothrombin G20210A), because each of these conditions may be associated with a hypercoagulable state.

The collagen-vascular disease workup includes the following:

• Lupus anticoagulant

• Erythrocyte sedimentation rate (ESR)

• Anti-DNA

• Anticardiolipin antibodies

• CH50 complement and components

• Antinuclear antibody (ANA)

• Rheumatoid factors

• Latex fixation

• Human leukocyte antigen (HLA) typing

Imaging studies for pediatric primary pulmonary hypertension include the following:

• Chest radiography

• Two-dimensional echocardiography

• Ventilation-perfusion imaging to rule out pulmonary thromboembolic disease

• MRI to assess airways and branch pulmonary arteries

• Radionuclide angiography to assess right ventricular function

Lung biopsy is not routinely necessary; the diagnosis is often made without this diagnostic procedure. If biopsy is performed, the findings allow confirmation of the diagnosis as well as a determination of severity.

The typical findings include pulmonary vascular medial hypertrophy, intimal fibrosis, and plexiform lesions in order of progression and severity.

Be aware that the risk of bleeding with open lung biopsy is considerable. Open lung biopsy is occasionally performed for diagnostic purposes. Biopsy also poses risks associated with anesthesia.

Other tests and procedures include the following:

• Electrocardiogram

• Pulmonary function tests, including lung volumes, diffusion capacity, and bronchodilator response

• Sleep study to rule out upper airway obstruction ^[7]

• Progressive exercise study

• Cardiac catheterization

Perform cardiac catheterization with acute vasodilator drug testing with oxygen, inhaled nitric oxide, prostacyclin, and nifedipine. Transseptal balloon dilation of the atrial septum is possible if symptoms of syncope associated with right heart failure are present.