Doppler echocardiography is the most appropriate test to perform next in this patient with a 3-year history of limited cutaneous systemic sclerosis (LcSSc) who now presents with shortness of breath and fatigue, a prominent single S2, and a normal pulmonary examination and chest radiograph. LcSSc is characterized by isolated distal skin thickening (face, neck, and hands distal to wrists), is typically not accompanied by internal organ fibrosis, and is more likely to be associated with pulmonary arterial hypertension (PAH). The initial screening test for those with systemic sclerosis who have suspected PAH is echocardiography, which can rapidly and noninvasively estimate elevated pulmonary pressure as well as rule out some etiologies in the differential diagnosis such as intracardiac shunts, valvular heart disease, or heart failure. A moderate to high tricuspid gradient correlates well with PAH confirmed with gold standard right heart catheterization, which is 97% specific but may not be sensitive.
Bronchoscopy with lavage is often used in immunocompromised patients with rapidly deteriorating lung function to assess for infection and/or pulmonary hemorrhage. This test is not indicated in a patient with findings suggestive of PAH.
B-type natriuretic peptide (BNP) or N-terminal proBNP levels should be assessed in patients suspected of having heart failure. Preliminary data suggest that N-terminal proBNP may be helpful in the assessment of PAH and may provide prognostic information. BNP and N-terminal proBNP measurement cannot be recommended at this time until further studies validate their usefulness in patients with PAH.
In patients with echocardiographic findings suggesting PAH, an array of studies (such as imaging of the chest to assess parenchymal lung disease; V/Q scanning to assess potential chronic thromboembolic disease; pulmonary function testing with DLCO; serologic studies for connective tissue disease, liver disease, and HIV; and sleep studies) are helpful in selected patients. All patients suspected of having PAH should be considered for right heart/pulmonary artery catheterization to confirm the diagnosis suggested by clinical presentation, echocardiography, and pulmonary function tests and to accurately measure the arterial pressure. It is also very useful in evaluating responsiveness to therapeutic medications and helps guide therapy. However, right heart catheterization follows these preliminary diagnostic tests and would not be done next.