The patient presented again 7 years later with dyspnea. He noted initial improvement in his respiratory symptoms after his discharge from the previous hospitalization; however, the improvement was short-lived. He was now limited to climbing less than a flight of stairs without stopping and he was sharing farm chores with his sons due to his limitations. His 6 min walk distance at that time was 209 m with a BORG dyspnea score of 10. He denied chest pain, lightheadedness and near syncope. He had lower extremity edema (right leg > left leg). Vital signs upon consultation demonstrated a blood pressure of 122/70 mmHg and a SaO₂ of 93% on 4 L/min. His BMI was 26 kg/m². His chest exam was notable for end-expiratory wheezes bilaterally. His cardiovascular exam noted a jugular venous pressure of 8 cm, a normal S1 and S2 and no appreciable murmurs. Pulmonary function tests revealed severe obstruction with a forced expiratory volume (FEV₁) = 1.1 L (35%) and a diffuse capacity adjusted for hemoglobin (DLCO) of 10.3 mL/mmHg/min (33% predicted). Forced vital capacity was 3.76 L (92%). His echocardiogram showed a mildly dilated right ventricle and an insufficient tricuspid regurgitant jet to estimate a right ventricular systolic pressure (RVSP) estimate. Laboratory assessment showed normal α-1 antitrypsin levels, a non-reactive antinuclear antibody, normal thyroid stimulating hormone and no evidence of hepatitis C virus or human immunodeficiency virus. Chest x-ray (Fig. 19.2) demonstrated flat hemidiaphragms, increased lung volumes and dilated intralobar pulmonary arteries: Past medical history was notable for emphysema and systemic hypertension .

Given the previous history of pulmonary embolism, a ventilation-perfusion scan was obtained. The study showed multiple moderate or large segmental perfusion defects throughout both lungs. Ventilation images showed xenon retention (Fig. 19.3).

Further assessment was obtained via CT pulmonary angiogram (Figs. 19.4 and 19.5).