Postpneumonectomy Pulmonary Artery Stump Thrombosis: CT Features and Imaging Follow-up

Abstract

To retrospectively evaluate the computed tomographic (CT) features of pulmonary artery stump thrombosis at initial and follow-up CT. The study was approved by institutional review board, which waived informed consent, and was HIPPA compliant. All patients who had undergone pneumonectomy and CT from January 2001 to August 2003, as identified with data search system, were included. Eighty-nine patients (49 men, 40 women; mean age, 60 years) were studied. Thrombus identification, categorization (concave or convex), and stump and thrombus measurements were made by two radiologists in consensus. The use of anticoagulation therapy was determined from patients' charts. The t test was used. Initial CT scans were obtained 34 months +/- 67 (standard deviation) after pneumonectomy; multiple CT scans were obtained in 58 patients during follow-up of 25.1 months +/- 24.8. Eleven (12.4%) of 89 patients had stump thrombi with near equal frequency on either side. Five concave and six convex thrombi were initially identified. Anticoagulation was not commenced for stump thrombosis. The mean length of the right stump (31 mm +/- 10) was greater than that of the left stump (13 mm +/- 7) (P < .01). After a right and left pneumonectomy, there was a significant difference between the length of the stump in patients with (right, 40 mm +/- 14; left, 21 mm +/- 11) and patients without thrombosis (right, 30 mm +/- 9; left, 12 mm +/- 6) (P = .027 and P < .01, respectively). Follow-up CT scans were not available in four cases. CT findings demonstrated a reduction in thrombus size in four patients (one received anticoagulation therapy for concomitant pulmonary embolism). Two patients had stable concave thrombi, one with an initial concave thrombus developed convex thrombus, and one with an initial convex thrombus developed concave thrombus. No thrombi propagated outside of the stump. There is a relationship between stump length and the development of in situ thrombosis. The data suggest a rather benign natural history.