Review Question - QID 109187

A 55-year-old African American male presents to his primary care provider complaining of shortness of breath. He has noticed progressively worsening difficulty running, walking up the stairs, and working out. His past medical history is notable for well-controlled asthma and osteoarthritis. He had a previous spinal surgery. He drinks alcohol socially and has never smoked. His family history is notable for emphysema in his father and myocardial infarction in his mother. He works as an investment banker, recently inherited some land, and is working on restoring a barn on the property. His temperature is 98.6°F (37°C), blood pressure is 135/85 mmHg, pulse is 100/min, and respirations are 24/min. Physical examination reveals bilateral rales at the lung bases. A chest radiograph is shown in Figure A. Which of the following is most likely responsible for this patient’s symptoms?