Review Question - QID 103004

This patient is presenting with gradual worsening dyspnea, bilateral hilar enlargement on radiography, and right axis deviation on ECG suggesting a diagnosis of pulmonary hypertension. The most accurate test for pulmonary hypertension is right-sided heart catheterization.

The diagnosis of pulmonary hypertension is often delayed due to its similar clinical presentation to congestive heart failure, coronary artery disease, pulmonary embolism, and other more common diseases. Patients may initially be asymptomatic with symptoms that progress to exertional dyspnea, fatigue, exertional chest pain, exertional syncope, and peripheral edema. Echocardiography can indirectly diagnose pulmonary hypertension by assessing right ventricular hypertrophy, right atrial size, right ventricular contractility, and estimates of pulmonary artery pressure. Right heart catheterization is the definitive diagnostic test, as it allows for direct measurement of pulmonary artery pressures and pulmonary artery occlusion pressure which can help differentiate between pre-capillary (pulmonary arterial hypertension) and post-capillary (pulmonary venous hypertension) pulmonary hypertension.

Figure A is a chest radiograph showing bilateral hilar enlargement which is a common finding in patients with pulmonary hypertension, as well as cardiomegaly. Figure B is an ECG demonstrating right axis deviation suggesting right heart strain which could be seen in any condition with right ventricular failure (such as pulmonary hypertension or a pulmonary embolism). Other findings in this ECG include diffuse repolarization abnormalities.

Incorrect Answers:
Answer 1: Cardiac MRI can be used to diagnose myocardial ischemia, cardiomyopathies, myocarditis, vascular diseases, and congenital heart disease; however, it can not confirm the pressure in the pulmonary artery thus it is not the most accurate test for pulmonary hypertension.

Answer 2: CT angiogram would be an appropriate accurate diagnostic test for a pulmonary embolism which presents with pleuritic chest pain, hypoxia, and sinus tachycardia in the setting of stasis or a hypercoagulable state. It is an unlikely diagnosis in a patient with a very slow onset of worsening dyspnea without constant chest pain (though right axis deviation could also be seen in this condition).

Answer 3: Echocardiogram is a non-invasive and accurate test for pulmonary hypertension and it can show signs of right ventricular strain; however, it is not the most accurate test for pulmonary hypertension as it can not confirm the pressure in the pulmonary artery.

Answer 4: Pulmonary function tests may reveal an isolated decrease in diffusing capacity with pulmonary arterial hypertension, and give insight into chronic lung disease with secondary pulmonary hypertension; however, it can not confirm the increased pulmonary artery pressure.

Bullet Summary:
The most accurate test for pulmonary hypertension is right heart catheterization.