Diagnosis and tests for Pulmonary Hypertension

Chest X-ray. Dilation of the main pulmonary arteries and their branches is usually seen, with decreased peripheral vascularisation. Increased heart size due to enlargement of the right heart chambers is common.

Electrocardiogram (ECG). The ECG result is normal in up to 90% of cases. This is a non-invasive examination to study the electrical activity of the heart at a certain time. The objective is to establish the frequency of the heartbeat, the type of heart rhythm and morphology of the electrical waves of the heart. It may show enlargement or distention of the right ventricle.

Analytical determinations. These help determine the cause of pulmonary arterial hypertension. Liver and thyroid function studies are done, serology for HIV and hepatitis B and C viruses, as well as analysis of antibodies associated with connective tissue diseases.

Echocardiogram. This provides a non-invasive estimation of pulmonary artery pressure, by assessing the properties of the right heart chambers, and ruling out heart disease as the origin of pulmonary hypertension. Therefore, this is the technique most often used in the detection of pulmonary hypertension.

Ventilation and perfusion lung scan. This measures the flow of air in the lungs (ventilation) and shows how the blood circulates in the lungs (perfusion). It must be done in all patients to rule out thromboembolic disease.

Pulmonary function tests. To evaluate how pulmonary hypertension affects lung function. It can also detect respiratory disease as the cause of the appearance of pulmonary hypertension.

Chest computed tomography (CT) scan. This is recommended when lung tissue involvement is suspected. This is the case with interstitial lung disease, veno-occlusive disease and pulmonary capillary haemangiomatosis. Contrast CT angiography, or Computed Tomography Angiography, can locate and quantify thromboembolic lesions.

Exercise stress tests. These evaluate the limitation of the patients' aerobic capacity (ability to do moderate exercise). The objective measurement of exercise tolerance can be done with simple tests, such as the 6-minute walk test, or complex tests, such as cardiopulmonary exercise tests on a cycle ergometer.

Pulmonary haemodynamic study. This is the tool that confirms the diagnosis of pulmonary hypertension and provides information on its severity and prognosis. It can also assess whether the disease is reversible, and to what degree, through the acute vasodilator test.