Pleural Adhesion Assessment as a Predictor for Pneumothorax after Endobronchial Valve Treatment

Abstract

Background: Pneumothorax after bronchoscopic lung volume reduction using one-way endobronchial valves (EBVs) in patients with advanced emphysema occurs in approximately 20% of patients. It is not well known which factors predict the development of pneumothorax. Objective: To assess whether pleural adhesions on pretreatment high-resolution computed tomography (HRCT) scans are associated with pneumothorax occurrence after EBV treatment. Methods: HRCT scan analyses were performed on all patients who received EBV treatment in a randomized controlled trial. Three blinded readers scored adhesions by number and by measuring the longest axis of each pleural adhesion in the treated lung. The Pleural Adhesion Score (PAS) was calculated by adding 1 point for each small pleural lesion (<1 mm), 5 points for each medium-sized lesion (1-5 mm), and 10 points for each large lesion (>5 mm). Results: The HRCT scans of 64 treated patients were assessed, of whom 14 developed pneumothorax. Patients who developed pneumothorax had a higher median number of pleural adhesions, 2.7 (IQR 1.9-4) compared to 1.7 (1-2.7) adhesions in the group without pneumothorax (p < 0.01). The PAS in the group with pneumothorax was higher compared to that in the group without: 14.3 (12.4-24.1) versus 6.7 (3.7-11.2) (p < 0.01). A threshold PAS of ≥12 was associated with a higher risk of pneumothorax (OR 13.0, 95% CI 3.1-54.9). A score <12 did not rule out the occurrence of pneumothorax. Conclusion: A higher number of pleural adhesions on HRCT with a subsequent higher PAS in the treated lung is associated with a higher occurrence of pneumothorax after EBV treatment.