Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 54-year-old woman is evaluated for a 1-year history of progressive exertional dyspnea. She does not smoke cigarettes or use illicit drugs. The patient has a history of obesity and has used various appetite suppressants but takes no other medications. She has no significant family or personal or medical history.

On physical examination, she is afebrile; the blood pressure is 100/60 mm Hg, the pulse rate is 98/min, the respiration rate is 20/min, and the BMI is 38 kg/m². The lungs are clear on auscultation and percussion. There is a loud pulmonic component to S₂, which is also split during inhalation and exhalation. Spirometry and plethysmography are normal.

Arterial blood gases are normal.

Ventilation/perfusion scan shows diffusely nonhomogeneous perfusion but no segmental or subsegmental regions of perfusion defect. Chest radiograph shows enlarged pulmonary arteries and enlarged right-sided heart chambers but no parenchymal abnormalities. Transthoracic echocardiography shows decreased cardiac output, right ventricular hypertrophy and dilation, and right atrial enlargement. The left ventricle is somewhat compressed by the intraventricular septum.

Which of the following is the most appropriate next step in the management of this patient?

A) High-resolution CT scan of the chest
B) Myocardial perfusion imaging
C) Right-heart catheterization
D) Therapeutic trial of enalapril
E) Transbronchial lung biopsy

MKSAP Answer and Critique

The correct answer is C) Right-heart catheterization. This item is available to MKSAP 15 subscribers as item 59 in the Pulmonology and Critical Care Medicine section. More information about MKSAP 15 is available online.

This patient has signs and symptoms of pulmonary hypertension and a history of use of appetite suppressants, which have been associated with pulmonary hypertension. Echocardiography has ruled out the presence of cardiac diseases associated with pulmonary hypertension. Pulmonary function testing has ruled out parenchymal obstructive and restrictive lung diseases, and ventilation/perfusion scanning has ruled out chronic thromboembolic pulmonary hypertension. Right-heart catheterization will confirm the presence of pulmonary arterial hypertension, measure pulmonary vascular resistance, determine the magnitude of right ventricular dysfunction, and guide therapy.

High-resolution CT scan is useful for the evaluation of pulmonary parenchymal disease, but the absence of parenchymal abnormalities on chest radiograph and the normal pulmonary function tests make interstitial disease unlikely. This patient’s physiologic testing discloses no evidence of lung parenchymal disease. Myocardial perfusion imaging can help detect compromised coronary flow. However, the echocardiographic findings can be explained by right ventricular overload and do not suggest acute coronary disease.

Lung biopsy would add little to the diagnosis of pulmonary hypertension and entails a risk of bleeding in patients with pulmonary hypertension. Therapy with an angiotensin-converting enzyme (ACE) inhibitor may improve left ventricular function in patients with left ventricular systolic dysfunction. However, this patient’s left ventricular dysfunction is attributable to compression from right ventricular hypertrophy and dilation. ACE inhibitors would not improve the pulmonary arterial resistance and might even cause dangerous decreases in this patient’s blood pressure.

Key Point

• In patients with pulmonary hypertension, right-heart catheterization will confirm the presence of pulmonary arterial hypertension, quantify pulmonary vascular resistance, determine the magnitude of right ventricular dysfunction, and guide therapy.

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