Chronic Thromboembolic Occlusion in the Adult Can Mimic Pulmonary Artery Agenesis: Chest x-ray film
A chest x-ray film disclosed cardiomegaly of right ventricular configuration, a hypoperfused left lung, a prominent right pulmonary artery and pleural thickening on the left side. Spirometry revealed mild expiratory obstruction. Lung volumes were normal. An ECG disclosed marked right axis deviation, incomplete right bundle branch block, nonspecific ST and T changes. Lung perfusion scan disclosed total absence of perfusion to the left lung and right middle lobe, and segmental defects in the right upper and lower lobes. Ventilation scans were normal.
At cardiac catheterization, the pulmonary artery pressure was 92/12 mm Hg (mean: 46 mm Hg); right atrial pressure (mean) 10; wedge pressure, 8 mm Hg. The CO was 4.08 L/min. Mild tricuspid insufficiency was present. Calculated pulmonary vascular resistance was 744 dvsnes*s»cm . There was no evidence of an intracardiac shunt.
Pulmonary angiography disclosed that 110 contrast material entered the left pulmonary artery. Radiographic interpretation was of left pulmonary agenesis with thromboembolism to the right lung involving total occlusion of the RML branch and two right basilar segmental branches. A CAT scan of the chest with contrast was noncontributory, with no evidence of a left pulmonary artery detected. further
Fortunately, a series of radiographs dating to 1977 were ultimately assembled. A 1977 chest x-ray film showed normal lung fields and pulmonary vasculature bilaterally (Fig 6). A chest x-ray film in February 1980 revealed oligemia of the left lung, no identifiable left pulmonary artery and enlargement of the cardiac silhouette (Fig 7).
Pulmonary angioscopy was performed and disclosed a large organized thrombus totally occluding the left main pulmonary artery as well as chronic thrombi in the right middle lobe and right basilar segmental arteries. The patient underwent successful bilateral pulmonary thromboendarterectomy. A chest x-ray film obtained three weeks after surgery disclosed restoration of the left pulmonary artery shadow and a decrease in cardiac size.
Figure 6. Chest x-ray film dated Oct 10, 1977 discloses normal central pulmonary arterial shadows bilaterally.
Figure 7. Chest x-ray film dated Feb 5, 1980 shows cardiomegaly, no identifiable left pulmonary artery and an avascular left lung.