Which of the following is the most appropriate initial test for this patient?
A 52-year-old man presents to your clinic complaining of progressive dyspnea, which he has been experiencing for 6 to 8 months. When he was a teenager, he underwent splenectomy after being involved in a motor vehicle accident. A few years ago, the patient had pneumonia. On examination today, results of auscultation of the patient's lungs and heart are normal. An ECG shows right ventricular hypertrophy and right atrial enlargement. A chest x-ray shows asymmetrical enlargement of the pulmonary arteries with regions of hyperperfusion and hypoperfusion.
A. Ventilation-perfusion lung scanning B. Pulmonary function testing C. Pulmonary angiography D. Transthoracic echocardiography
Ventilation-perfusion lung scanning-patients with chronic thromboembolic pulmonary hypertension (cteph) usually present months or years after the initial (and often asymptomatic) embolic event(s) with symptoms of pulmonary hypertension. the initial event may have been diagnosed as an episode of embolism (in only 50% of cases) or may have been undiagnosed or misdiagnosed as pneumonia. medical conditions associated with an increased risk of the development of cteph are splenectomy, ventriculoatrial shunt for the treatment of hydrocephalus, and chronic inflammatory disorders such as osteomyelitis and inflammatory bowel disease. the chest radiograph may be normal or may show abnormalities. findings suggestive of cteph include asymmetrical enlargement of the pulmonary arteries, regions of hyperperfusion and hypoperfusion, and focal fibrotic areas of old infarction that may be associated with local pleural thickening or cavitation. the ecg typically shows changes of right ventricular hypertrophy or strain, right atrial enlargement, and right bundle branch block. pulmonary function tests will most commonly show no abnormality of lung volumes or of spirometry measurements. the ventilation-perfusion lung scan is the best method of screening patients with pulmonary hypertension to identify those in whom the disorder may be caused by chronic thromboembolism. patients with chronic thromboembolism will have at least one segmental or larger perfusion defect. when large perfusion defects are seen on the ventilation-perfusion scan, additional testing is needed to confirm that the defects are caused by chronic thromboembolism. spiral ct is a noninvasive imaging technique that can allow identification of proximal chronic clots and detect other causes of pulmonary vascular obstruction. the use of pulmonary angiography in patients with pulmonary hypertension has been thought to be associated with a significant risk of death or adverse outcome.