Group 2 Pulmonary Hypertension Workup

Updated: Jul 30, 2021
  • Author: Nikhil Barot, MD, MS; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Workup

Approach Considerations

Initial screening tests with two-dimensional transthoracic echocardiography revealing elevated pulmonary artery systolic pressure (PASP) and/or right ventricular dysfunction should prompt further diagnostic evaluation for underlying pulmonary hypertension.

Invasive testing with right-sided heart catheterization (RHC) is used to confirm the diagnosis of pulmonary hypertension. RHC is also useful for vasodilator testing.

As previously mentioned, a comprehensive workup for other pulmonary hypertension WHO groups 1, 3, 4, and 5 should be undertaken as this can influence the treatment options available.

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Laboratory Studies

Baseline complete blood cell count, basic metabolic panel, and liver function tests should be obtained in all patients. Serologic evaluation for other etiologies of WHO groups 1, 3, 4, and 5 pulmonary hypertension should be obtained in order to identify concomitant etiologies. In patients with volume overload, obtaining a brain natriuretic peptide (BNP) level and troponin level can be helpful in establishing baseline values and as a means to monitor degree of chamber stretch and myocardial injury.

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Electrocardiography

Electrocardiography findings in pulmonary hypertension are nonspecific but may suggest right ventricular disease. Signs of right ventricular hypertrophy include right axis deviation, incomplete and complete right bundle-branch block, and an R-wave-to-S-wave ratio greater than 1 in lead V1. Additionally, increased P-wave amplitude in lead II is indicative of right atrial enlargement.

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Chest Radiography and Computed Tomography

Chest radiography in patients with pulmonary hypertension due to left-sided heart disease (PH-LHD) demonstrates enlarged central pulmonary arteries with or without oligemic lung fields depending on the patient’s underlying volume status (see image below). Signs of right atrial and ventricular dilation can include a diminished retrocardiac space and prominent right-sided heart border. Additionally, an enlarged cardiac silhouette with prominent left-sided heart border can found in group 2 pulmonary hypertension. In the setting of acute exacerbation, edema at the lung bases can be noted. Abnormalities found on chest radiographs can be followed up with computed tomography.

Chest radiograph of a patient with pulmonary hyper Chest radiograph of a patient with pulmonary hypertension due to left-sided heart disease from heart failure with reduced ejection fraction showing enlarged pulmonary arteries, mild pulmonary vascular congestion, and dilated right atrium and left atrium.
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Echocardiography

Echocardiography is used to evaluate right ventricular systolic pressure (sometimes expressed as pulmonary artery systolic pressure, [PASP]), chamber size, right and left ventricular systolic and diastolic function, valvular function, and presence of pericardial effusion (see the image below). Doppler echocardiography can be used to estimate PASP using the tricuspid regurgitant jet velocity and right atrial pressure. The efficacy of measuring PASP depends on the ability to locate the tricuspid regurgitant jet. An important aspect to determining WHO group 2 pulmonary hypertension due to left-sided heart disease (PH-LHD) is the measurement of left atrial size in which a dilated left atrium is suggestive of chronic elevated left atrial pressures due to left-sided heart disease. In determining the underlying etiology of pulmonary hypertension, bubbles can be administered to detect intracardiac shunts. In the setting of right ventricular overload, systolic flattening of the intraventricular septum and thickening of the right ventricular free wall may be observed. As a result of chronic right ventricular overload, tricuspid regurgitation, right atrial dilatation, and hypokinesis of the right ventricular free wall may be present.

Transthoracic echocardiograph showing an apical fo Transthoracic echocardiograph showing an apical four-chamber view of the same patient with pulmonary hypertension due to heart failure with reduced ejection fraction. The right atrium and ventricle are notably dilated.
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Right-Sided Heart Catheterization

Right-sided heart catheterization (RHC) is used to confirm the diagnosis of pulmonary hypertension and can be used to differentiate group 2 pulmonary hypertension from other underlying etiologies. Measurements obtained from RHC include pulmonary capillary wedge pressure (PCWP), mean pulmonary arterial pressure (mPAP), cardiac output (CO), pulmonary vascular resistance (PVR) reported in Wood units (WU), transpulmonary gradient (TPG), and diastolic pressure gradient (DPG).

TPG is the difference between the mPAP and the mean PCWP (mPCWP), with a normal value being less than 12 mm Hg. The Fifth World Symposium in pulmonary hypertension recommended using DPG, the difference between diastolic PAP and mPCWP, to differentiate isolated postcapillary pulmonary hypertension (Ipc-PH) from combined postcapillary and precapillary pulmonary hypertension (Cpc-PH). [4] The DPG is more specific in identifying pulmonary hypertension due to left-sided heart disease (PH-LHD) patients who have undergone pathophysiologic remodeling since the DPG is less sensitive to changes in pulmonary vascular flow rate (which can be variable due to dynamic changes in stroke volume and cardiac output), resistance, and PCWP. One study found that a DPG greater than 7 mm Hg is an independent predictor of survival in patients with PH-LHD. [12]

On the basis of these measurements during RHC, PH-LHD can be divided into the following two categories:

  • IpcPH (mPAP >20 mm Hg, mPCWP >15 mm Hg, TPG >12 mm Hg, DPG < 7 mm Hg, and/or PVR < 3 WU)
  • CpcPH (mPAP >20 mm Hg, mPCWP >15 mm Hg, TPG >12mm Hg, DPG >7 mm Hg, and/or PVR >3 WU)

Some controversy exists regarding vasodilator testing in the setting of group 2 pulmonary hypertension. Vasoreactivity testing includes the use of prostanoids, nitrous oxide, nitroprusside, or phosphodiesterase-5 inhibitors. Testing is recommended when pulmonary hypertension is out of proportion or in heart transplantation candidates. [5] The goal of testing is to determine if pulmonary hypertension is reversible (reduction in TPG and PVR without change in CO or raising PCWP) with the use of vasodilators. However, there are no current guidelines on the definition for reversibility in group 2 pulmonary hypertension.

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Other Tests

Other etiologies of pulmonary hypertension should be evaluated with a ventilation perfusion scan (to assess for chronic thromboembolic pulmonary hypertension), polysomnography (to assess for obstructive sleep apnea), and pulmonary function tests (to assess for restrictive or obstructive pulmonary disease).

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