Prediction of lobar collateral ventilation in 25 patients with severe emphysema by fissure analysis with CT.

Abstract

Reducing pulmonary volume through implantation of endobronchial valves is a major interest to improve exercise tolerance and survival in patients with severe emphysema. The primary aim of this study was to evaluate how well CT-determined fissure integrity predicts interlobar collateral ventilation. The secondary objective was to show whether there is a relationship between the size of fissural defects and the presence of collateral ventilation. Thirty patients with heterogeneous emphysema (postbronchodilator forced expiratory volume in 1 second [FEV1] = 20-50% predicted and > 50% of emphysema in a lobe) underwent collateral ventilation measurements with a catheter through an occlusive balloon within this target lobe during flexible endoscopy. Two senior thoracic radiologists studied the fissures on thoracic high-resolution CT. Collateral ventilation was successfully measured in 37 target lobes in 25 patients. The fissures surrounding the 37 target lobes were evaluated on CT. For the detection of collateral ventilation, the presence of a fissural defect on CT has a sensitivity, specificity, positive predictive value, and negative predictive value of 95%, 44%, 69%, and 88%, respectively. There was a statistically significant difference in the area of the defect between patients with collateral ventilation and those without collateral ventilation (p = 0.04). Analysis of pulmonary fissures using CT is useful before endoscopic volume reduction because results are well correlated to endoscopic measurements of collateral ventilation. Further study with clinical outcomes is mandatory to determine if and when one test or the other or both should be used in patient selection.