Pulmonary arterial hypertension is often not diagnosed in a timely manner because its early symptoms can be confused with those of other cardio-respiratory conditions. Symptoms can initially be subtle and relatively non-specific. A process of exclusion generally makes diagnosis of PAH by looking for and ruling out other diseases (see below).
In fact there is often a lengthy delay between the time when patients first visit their general practitioner and the time when they receive specialist care at a hospital. The average delay is 2,5 years.
Diagnostic work up
The evaluation of a patient with suspected pulmonary hypertension requires a series of investigations intended to:
- confirm the diagnosis;
- establish the type of PH according to the current diagnostic classification (see specific section) and, within PAH, the particular sub-group;
- evaluate the functional and haemodynamic impairment.
The diagnosis of PAH is a diagnosis of exclusion. Each step of the work up narrows down the range of possibilities in order to arrive at PAH and the specific form of PAH.
- Electrocardiogram: may provide suggestive evidence of PH by demonstrating right ventricle enlargment and strain, and right atrial dilatation.
- Chest X ray: useful to exclude lung diseases (group 3 of the PH diagnostic classification) such as COPD, emphysema, intersitital lung disease or pulmonary venous hypertension due to left heart disease (LHD), (group 2);
- Pulmonary function tests and arterial blood gases will identify underlying airway or lung diseases (see above, group 3);
- Echocardiography provides several variables which correlate with right heart haemodynamics including pulmonary arterial pressure (PAP). Is helpful in detecting the cause of suspected PH, eg congenital heart disease (CHD) or left heart disease (LHD);
- Ventilation/perfusion lung scan: should be performed in patients with PH to look for potentially treatable chronic thromboembolic pulmonary hypertension (CTEPH, group 4).
- High-resolution computed tomography, contrast-enhanced computed tomography, and pulmonary angiography: high-resolution CT facilitates the diagnosis of interstitial lung disease and emphysema; high-resolution CT may be helpful where there is a clinical suspicion of PVOD (group 1’); contrast CT angiography can determine whether there is evidence of surgically accessible CTEPH.
- Blood tests and immunology are important to detect underlying connective tissue disease (CTD), HIV, and hepatitis.
- Abdominal ultrasound scan: Liver cirrhosis and/or portal hypertension can be excluded by the use of abdominal ultrasound.
- Right heart catheterization and vasoreactivity RHC are required to confirm the diagnosis of PAH (group 1), to assess the severity of the haemodynamic impairment, and to test the vasoreactivity of the pulmonary circulation. In PAH, vasoreactivity testing should be performed at the time of diagnostic RHC to identify patients who may benefit from long-term therapy with calcium channel blockers (CCBs).
Source: ESC guidelines on Pulmonary hypertension (http://www.escardio.org/guidelines-surveys/esc-guidelines/Pages/pulmonary-arterial-hypertension.aspx)
PHA, the US patient association, has recently launched a campaign targeted at medical professionals to improve the knowledge of the disease and achieve a more timely diagnosis.
Sometimes it’s PH is a multi-year initiative by the Pulmonary Hypertension Association (PHA) to reduce the time from the onset of symptoms to diagnosis of PH. PHA is mobilizing to change aspects of medical practice so that more patients may gain access to approved treatments and specialty care centers before the disease progresses to advanced stages. See website and video at: http://www.phassociation.org/SometimesItsPH
The video is currently available in 19 languages.