A 75-year-old woman presented with worsening dyspnea of about 6 to 8 months' duration. Her symptoms were initially associated with exercise, after about 30 minutes on the treadmill, and now were present at rest. Her breathing pattern had changed to "panting" to improve airflow during minimal activity.
The patient had a 40 pack-year smoking history but had quit 18 years earlier. She had hypertension, controlled with antihypertensive agents, and depression, for which she was not taking any medications. She denied heart or lung disease and use of alcohol or illicit drugs. Her father had a history of coronary artery disease.
On examination, the patient was in minimal distress. Blood pressure was 130/76 mm Hg; heart rate, 73 beats per minute; respiration rate, 20 breaths per minute; and temperature, 36.7[degrees]C (98.1[degrees]F). Oxygen saturation was 90% on room air. Head, neck, heart, lung, and abdominal findings were unremarkable. Trace pitting edema was noted in the lower extremities; signs of cyanosis or clubbing were absent.
Results of a complete blood cell count and complete metabolic panel were normal. A chest radiograph showed a tortuous right-sided aortic arch but an otherwise unremarkable cardiomediastinal silhouette; the lungs were clear without evidence of focal collapse, consolidation, effusion, or pneumothorax (Figure 1).
Pulmonary function test results showed only mild obstruction without a significant bronchodilator response. Results of a flow-volume loop test did not show clear evidence of fixed or variable upper airway obstruction.
A high-resolution CT scan of the chest confirmed a right-sided aortic arch; a small ductus diverticulum was also noted just distal to the origin of the left subclavian artery, which was causing near circumferential compression of the trachea (Figure 2). Tracheal diameter at...