Morphologic grading of the emphysematous lung and its relation to improvement after lung volume reduction surgery.

Background: The morphologic criteria for lung volume reduction surgery, such as severity and heterogeneity of disease, differ widely between patients, and this makes any comparison of functional results between centers difficult. Here we present a morphologic scoring system and describe its possible relation to functional results after lung volume reduction operations.

Methods: Between September 1994 and December 1996, 47 consecutive patients underwent bilateral lung volume reduction operations. The morphology of emphysema was quantified with standard chest roentgenograms and computed tomographic imaging, which were used to define the following four variables: degree of hyperinflation (grade 0 to 4), degree of impairment in diaphragmatic mechanics, degree of heterogeneity (grade 0 to 4), and severity of parenchymal destruction (range, 0 to 48).

Results: All four variables showed good reproducibility. Degree of heterogeneity had a significant influence on functional improvement in terms of forced expiratory volume in 1 second (p = 0.0413, r2 = 0.11). Severity of parenchymal destruction was significantly associated with 30-day mortality: patients who died after operation (n = 4) had a severity of parenchymal destruction of 28.4 +/- 2.1 compared with 21.3 +/- 1.0 for those who survived (n = 43) (p = 0.003).

Conclusions: This morphologic scoring system is easy to use, is reproducible, and allows quantification of the morphology of emphysema, thereby allowing definition of different patient subgroups. Such an exact morphologic quantification may help in the comparison of functional results between centers. Furthermore, the risk factors for certain morphologic subgroups, such as patients with a homogeneous distribution pattern, may be clarified in the future.