From the Guidelines
Acute pulmonary hypertension workup should start with a comprehensive diagnostic evaluation, including echocardiogram, laboratory tests, and imaging studies, to accurately diagnose and characterize the disease phenotype.
Initial Evaluation
The initial evaluation of suspected pulmonary hypertension should include:
- Echocardiogram to assess right ventricular systolic pressure (RVSP) and function
- Laboratory tests, such as:
- Complete blood count (CBC)
- Comprehensive metabolic panel
- Thyroid function tests
- N-terminal pro B-type natriuretic peptide (NT-proBNP)
- Hepatitis serologies
- HIV testing
- Imaging studies, such as:
- Chest X-ray
- Non-contrast CT scan of the chest or CT angiogram if thromboembolic disease is suspected
- V/Q scan to evaluate for chronic thromboembolic pulmonary hypertension (CTEPH)
Further Evaluation
If the initial evaluation suggests pulmonary hypertension, further testing may include:
- Right heart catheterization to measure pulmonary artery pressure and assess vasoreactivity
- Pulmonary function tests to evaluate lung function
- Six-minute walk test to assess functional capacity
- Sleep study to evaluate for sleep apnea
- Autoimmune antibody panel if there is a suspicion of autoimmune disease
Diagnostic Algorithm
The diagnostic algorithm for pulmonary hypertension should follow a step-wise approach, starting with non-invasive tests and progressing to invasive tests as needed 1. The American College of Radiology (ACR) Appropriateness Criteria for suspected pulmonary hypertension provide a framework for selecting the most appropriate imaging tests, including echocardiography, chest X-ray, CT angiography, and V/Q scan 1. It is essential to note that the workup for acute pulmonary hypertension should be individualized based on the patient's clinical presentation, medical history, and risk factors for disease.
From the Research
Workup for Acute Pulmonary Hypertension
The workup for acute pulmonary hypertension involves a stepwise approach to discern patients who need to be referred to a pulmonary hypertension center and undergo invasive hemodynamic assessment 2. The following steps are involved in the workup:
- Initial evaluation to identify the cause of pulmonary hypertension, which helps guide appropriate treatment 3
- Transthoracic Doppler echocardiography as a noninvasive test to detect the presence of pulmonary hypertension 4
- Right heart catheterization to confirm the diagnosis and assess hemodynamic parameters such as mean pulmonary arterial pressure, pulmonary arterial wedge pressure, and pulmonary vascular resistance 4, 2, 5
- Laboratory tests and imaging studies to rule out known causes of pulmonary hypertension and assess disease severity 4, 6
- Assessment of right ventricular function to follow up the clinical course and response to therapy 6
Diagnostic Criteria
Pulmonary hypertension is defined by a mean pulmonary artery pressure greater than 20 mm Hg, and is classified into 5 clinical groups based on etiology, pathophysiology, and treatment 2, 5. The diagnostic criteria for pulmonary arterial hypertension include:
- Mean pulmonary artery pressure greater than 20 mm Hg
- Pulmonary artery wedge pressure of 15 mm Hg or lower
- Pulmonary vascular resistance of 3 Wood units or greater 5
Referral to a Pulmonary Hypertension Center
Patients with high probability of severe pulmonary vascular disease, especially those with signs of right heart failure, should be referred to a pulmonary hypertension center for further evaluation and management 2. A fast-track referral is recommended at any point during the clinical workup if there is a high suspicion of pulmonary hypertension 2.