Jornal Brasileiro de Pneumologia (Aug 2012)
Índice de enfisema pulmonar em coorte de pacientes sem doença pulmonar conhecida: influência da idade Emphysema index in a cohort of patients with no recognizable lung disease: influence of age
Abstract
OBJETIVO: Investigar os efeitos da idade no enfisema pulmonar, com base nos valores do índice de enfisema (IE) em uma coorte de pacientes que nunca fumou e que não possuía doença pulmonar conhecida. MÉTODOS: Foram revisados exames de TC, considerados normais, de 315 pacientes. Tabagismo, doenças cardiorrespiratórias e exposição a drogas que poderiam causar doença pulmonar foram critérios de exclusão. Dessa coorte, selecionamos 32 pacientes (16 homens e 16 mulheres), igualmente divididos em dois grupos (idade 50 anos), que foram pareados por gênero e índice de massa corpórea. Realizou-se a quantificação do enfisema utilizando um programa específico. O IE foi calculado com um limiar de -950 UH. O volume pulmonar total (VPT) e a densidade pulmonar média (DPM) também foram avaliados. RESULTADOS: As médias gerais de VPT, DPM e IE foram 5.027 mL, -827 UH e 2,54%, respectivamente. A comparação entre os mais velhos e os mais novos mostrou as seguintes médias: VPT, 5.229 mL vs. 4.824 mL (p > 0,05); DPM, -846 UH vs. -813 UH (p OBJECTIVE: To investigate the effects of age on pulmonary emphysema, based on the values of the emphysema index (EI) in a cohort of patients who had never smoked and who had no recognizable lung disease. METHODS: We reviewed the CT scans, reported as normal, of 315 patients. Exclusion criteria were a history of smoking, cardiorespiratory disease, and exposure to drugs that could cause lung disease. From this cohort, we selected 32 patients (16 men and 16 women), matched for gender and body mass index, who were divided equally into two groups by age ( 50 years). We quantified emphysema using a computer program specific to that task. The EI was calculated with a threshold of -950 HU. We also evaluated total lung volume (TLV) and mean lung density (MLD). RESULTS: The overall means for TLV, MLD, and EI were 5,027 mL, -827 HU, and 2.54%, respectively. Mean values in the older and younger groups, respectively, were as follows: for TLV, 5,229 mL vs. 4,824 mL (p > 0.05); for MLD, -846 HU vs. -813 HU (p < 0.04); and for EI, 3.30% vs. 1.28% (p < 0.001). Significant correlations were found between EI and age (r = 0.66; p = 0.001), EI and TLV (r = 0.58; p = 0.001), and EI and MLD (r = -0.67; p < 0.001). The predicted EI per age was defined by the regression equation (r² = 0.43): p50(EI) = 0.049 × age - 0.5353. CONCLUSIONS: It is important to consider the influence of age when quantifying emphysema in patients over 50 years of age. Based on the regression analysis, EI values of 2.6%, 3.5%, and 4.5% can be considered normal for patients 30, 50, and 70 years of age, respectively.
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