Influence of emphysema distribution on pulmonary function parameters in COPD patients

Abstract

OBJECTIVE: To evaluate the impact that the distribution of emphysema has on clinical and functional severity in patients with COPD. METHODS: The distribution of the emphysema was analyzed in COPD patients, who were classified according to a 5-point visual classification system of lung CT findings. We assessed the influence of emphysema distribution type on the clinical and functional presentation of COPD. We also evaluated hypoxemia after the six-minute walk test (6MWT) and determined the six-minute walk distance (6MWD).RESULTS: Eighty-six patients were included. The mean age was 65.2 ± 12.2 years, 91.9% were male, and all but one were smokers (mean smoking history, 62.7 ± 38.4 pack-years). The emphysema distribution was categorized as obviously upper lung-predominant (type 1), in 36.0% of the patients; slightly upper lung-predominant (type 2), in 25.6%; homogeneous between the upper and lower lung (type 3), in 16.3%; and slightly lower lung-predominant (type 4), in 22.1%. Type 2 emphysema distribution was associated with lower FEV1, FVC, FEV1/FVC ratio, and DLCO. In comparison with the type 1 patients, the type 4 patients were more likely to have an FEV1 < 65% of the predicted value (OR = 6.91, 95% CI: 1.43-33.45; p = 0.016), a 6MWD < 350 m (OR = 6.36, 95% CI: 1.26-32.18; p = 0.025), and post-6MWT hypoxemia (OR = 32.66, 95% CI: 3.26-326.84; p = 0.003). The type 3 patients had a higher RV/TLC ratio, although the difference was not significant. CONCLUSIONS: The severity of COPD appears to be greater in type 4 patients, and type 3 patients tend to have greater hyperinflation. The distribution of emphysema could have a major impact on functional parameters and should be considered in the evaluation of COPD patients.

Quantitative computed tomography measurements of emphysema for diagnosing asthma-chronic obstructive pulmonary disease overlap syndrome

“…More COPD patients are ULP than asthma patients, which is consistent with the fact that emphysema is more likely to involve the upper lung lobes in COPD. 35 These results suggest that extent and distribution of emphysema measured by quantitative CT may contribute to the differential diagnosis of COPD and asthma.…”

Decreased levels of irisin, a skeletal muscle cell-derived myokine, are related to emphysema associated with chronic obstructive pulmonary disease

“…Results revealed a strong correlation between emphysema and decreased serum irisin levels. In general, progressive or developed emphysema is usually found in the upper-lung area in patients with COPD,16,22 and %LAA for the upper-lung area exhibited the strongest correlation with serum irisin levels when lung fields were divided equally into three sections. Previous reports have shown significant correlations between %LAA and BMI23 and body-composition measurements, such as FFMI 24.…”

Variations of flow in human airways as a consequence of lung diseases

“…Then the data for several diseases were acquired. The data for asthmatics were obtained also from the study of Choi et al [6], the data on emphysema were from [10], on cancer from [11] and on lobectomy from [12].…”