Noninvasive imaging for the diagnosis and prognosis of pulmonary hypertension

Abstract

Pulmonary hypertension (PH) is a major cause of morbidity and mortality, but it often presents with nonspecific symptoms, thereby delaying diagnosis and treatment. While invasive cardiac catheterization is essential to confirm the diagnosis, patients with breathlessness are commonly encountered in clinical practice creating a demand for noninvasive screening methods. Preliminary investigations such as the electrocardiogram and chest radiograph lack sensitivity even in advanced cases. Echocardiography is used to screen patients; however, over-reliance on a single estimation of pulmonary artery systolic pressure is unwise, instead multiple parameters should be assessed. Once a diagnosis of PH is made, radionuclide imaging should be performed to exclude chronic thromboembolic disease, and computed tomography is vital for eliminating parenchymal lung disease as a potential etiology. Currently, the primary contribution of cardiac MRI is the accurate assessment of right ventricular size and function. In this respect, cardiac MRI may be supportive during diagnosis of PH, but the main importance of this is in defining prognosis although new outcome variables are anticipated.

Keywords::

• cardiovascular magnetic resonance imaging
• computed tomography
• diagnosis
• echocardiography
• etiology
• prognosis
• pulmonary hypertension

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Pulmonary hypertension (PH) is a hemodynamic state defined as a mean pulmonary arterial pressure >25 mmHg.

• Noninvasive assessments need to be used judiciously as they can falsely reassure clinicians. Suspected PH on noninvasive testing should always be confirmed by invasive measurement of pressures.

• A normal ECG and chest radiograph cannot exclude even advanced PH.

• Although transthoracic echocardiography is an excellent screening tool, there are commonly encountered pitfalls when estimating pulmonary arterial pressures using tricuspid regurgitant jet velocity alone. Multiple echocardiographic parameters should be combined before reaching a conclusion.

• In addition to screening and identification of left side heart disease, there is a wealth of data supporting the use of certain echocardiographic variables to predict prognosis in PH.

• Most cases of PH are due to left heart disease, and transthoracic echocardiography is the first step to be taken in defining etiology.

• Computed tomography is currently unable to reliably diagnose PH but is invaluable when investigating the second most common etiology of PH, chronic lung disease.

• Cardiac magnetic resonance is the ‘gold standard’ investigation for description of right ventricular anatomy and function.

• There are data to support the use of cardiac magnetic resonance imaging variables to predict prognosis in PH, but further large-scale, multicenter data are warranted and anticipated.

Notes