Diagnostics

• Screen and monitor patients with conditions at high risk of PH for suggestive clinical features

• If clinical suspicion is high for PH, perform transthoracic echocardiography (TTE) to noninvasively identify markers of elevated pulmonary artery pressure.

• If TTE suggests PH and the etiology is not yet known, begin evaluation for the most common underlying causes.

  • Identify clinical evidence of left heart disease and/or chronic lung disease and consider supportive investigations (e.g., ECG, CXR, BNP, PFTs) as directed by clinical suspicion.

  • If these are inconclusive, perform a V/Q scan to evaluate for thromboembolic disease.

• If the etiology remains unclear, TTE is equivocal, and/or severe PH is identified:

  • Consult a PH specialist.

  • Refer for confirmatory right heart catheterization.

  • Consider more advanced investigations, e.g., genetic screening.

CXR, ECG, and laboratory studies

first-line study in all patients with suspected PH

• ↑ Tricuspid regurgitation velocity (TRV)

• Right ventricular pressure overload

  • Flattening of the interventricular septum

  • Hypertrophy of the right ventricle

  • Dilation of the coronary sinus

• Right ventricular failure

  • Dilation and hypokinesis of the right ventricle

  • Right atrial dilation

• Underfilled left heart chambers

• Evidence of underlying cardiovascular disease

  • Left ventricular dysfunction

  • Mitral regurgitation

  • Mitral stenosis

  • Thrombus in the right heart, pulmonary artery, or IVC

• Confirmatory test for pulmonary hypertension

• Detailed assessment of other cardiac diseases (e.g., valvular heart disease, coronary artery disease)

mPAP > 20 mm Hg at rest is considered diagnostic for PH

• Precapillary pulmonary hypertension, e.g., PAH

  • Pulmonary vascular resistance ≥ 3 Wood units (normal: 0.25–1.6 Wood units)

  • PCWP ≤ 15 mm Hg

• Postcapillary pulmonary hypertension and mixed pre- and postcapillary pulmonary hypertension, e.g., secondary to left heart disease

  • Pulmonary vascular resistance is variable.

  • PCWP > 15 mm Hg

• Typically shows nonspecific changes secondary to increased right ventricular workload

  • Right ventricular hypertrophy

  • Right-axis deviation

  • P pulmonale

  • Incomplete or complete right bundle branch block

  • S1Q3T3

• May also show signs of underlying etiology, e.g., ischemic heart disease

Chest x-ray findings may help to support the diagnosis of PH

• Right heart hypertrophy

  • Prominent right heart border

  • Lateral view: loss of retrosternal space due to right ventricular enlargement

• Vascular changes

  • Enlarged central pulmonary arteries

  • Reduction in number and size of vessels of the peripheral pulmonary vasculature (referred to as pulmonary vascular pruning)

• Signs of the underlying cause (e.g., nodular opacities in interstitial lung disease, hyperinflation in COPD, pulmonary venous congestion in left heart disease)

• Left heart disease: NT-proBNP

• Chronic lung disease

  • Arterial blood gas

  • Pulmonary function tests

  • Diffusion capacity for carbon monoxide

  • Consider CT chest and sleep studies.

• Chronic pulmonary thromboembolism: V/Q scan

• Drug-induced: e.g., urine drug screen

• Portopulmonary hypertension: Send liver chemistries, consider ultrasound liver.

• Infection (based on risk factors): e.g., screen for HIV and schistosomiasis.

• Connective tissue disease (most commonly systemic sclerosis): e.g., antinuclear antibodies, anticentromere antibodies, anti-Scl-70 and anti-RNA polymerase III

• Sarcoidosis: e.g., inflammatory markers, serum calcium, ACE levels

• Hereditary: e.g., genetic testing