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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the relationship between the extent of pulmonary emphysema, assessed by quantitative high-resolution computed tomography (HRCT), and lung mechanics in 24 patients with chronic obstructive pulmonary disease (COPD). The extent of emphysema was quantified as the relative lung area with CT numbers < -950 Hounsfield Units (HU). Patients with COPD had severe airflow obstruction (FEV(1) 35 +/- 15% pred) and severe reduction of CO diffusion constant (DCO/VA 37 +/- 19% pred). Maximal static elastic recoil pressure (Pst(max)) averaged 54 +/- 24% predicted, and the exponential constant K of pressure-volume curves was 258 +/- 116% predicted. Relative lung area with CT numbers < -950 HU averaged 21 +/- 11% (range 1 to 38%). It showed a highly significant negative correlation with DCO/VA (r = -0.84, p < 0.0001), a weak correlation with FEV(1)% predicted, and no correlation with either Pst(max) or constant K. A significant relationship was found between the natural logarithm of K and the full width at half maximum of the frequency distribution of CT numbers, taken as an index of the heterogeneity of lung density (r = 0.68, p < 0.0005). We conclude that currently used methods of assessing the extent of emphysema by HRCT closely reflect the reduction of CO diffusion constant, but cannot predict the elastic properties of the lung tissue.
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PMID:Relationship between extent of pulmonary emphysema by high-resolution computed tomography and lung elastic recoil in patients with chronic obstructive pulmonary disease. 1152 Jul 20

To determine the role of the alveolar pores in cigarette smoke-induced lung disease, we examined the alveolar pores of guinea pigs exposed to cigarette smoke for 12 months, and compared these data to those obtained from sham-smoked animals, correlating the data with airspace size and lung function. We found that the smoke-exposed animals had a larger mean number of pores per alveolus (p < 0.001), and the distributions of pore size and shape were significantly shifted to indicate a larger and more irregular pore configuration (p < 0.001, 01 respectively). In the smoke exposed group, there was a significant correlation of pore number with total lung capacity (TLC) (0.68 p < 0.05), RV (0.70, p < 0.05), and FEV(0.1)/FVC(-0.77, p < 0.02). No correlations were identified between pore size or shape and the lung function tests. We conclude that cigarette smoke exposure produces an increase in the number of alveolar pores, a process which we believe represents ultramicroscopic emphysema. These alterations appear to precede any increase in airspace size, and may help to explain abnormal lung function in cigarette smokers without macroscopic emphysema or small airway disease. This is the first study to clearly document an increased number of alveolar pores, with a significant number of either/or large and irregular pores, after chronic smoke exposure, but in the absence of gross emphysema.
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PMID:The importance of ultramicroscopic emphysema in cigarette smoke-induced lung disease. 1173 50

The FEV(1) declines rapidly in alpha(1)-antitrypsin deficiency (alpha(1)-ATD) but less is known about other measures of disease severity and the factors, other than smoking, that are associated with progression of emphysema. The natural history of alpha(1)-ATD was studied prospectively in 43 patients with the PiZ phenotype and emphysema at a single center over 2 yr. The mean +/- SE change in FEV(1) was -67 +/- 14 ml/yr, accompanied by a reduction in transfer factor (mean change in diffusing capacity of the lung for CO [DL(CO)] -1.07 +/- 0.21 ml/min/mm Hg/yr; p < 0.001) and lung density in the upper zones as assessed by quantitative high-resolution computed tomography (HRCT) (mean change in voxel index 2.8 +/- 0.6%/yr; p < 0.001). The decline in FEV(1) related to baseline FEV(1) (r = -0.56, p < 0.001), bronchodilator reversibility (r = 0.52, p < 0.001), and (for patients with FEV(1) > 35% predicted) exacerbation frequency (r = -0.38, p = 0.02). There was also a decline in the St. George's Respiratory Questionnaire (SGRQ) Activity score (mean change -4.3 +/- 1.2 units/yr, p < 0.001) that correlated with FEV(1) decline (r = 0.45, p = 0.002). Progression of emphysema in alpha(1)-ATD is dependent on baseline physiology and exacerbation frequency and may be detected by several different measurements of which HRCT density mask analysis and DL(CO) appear most sensitive.
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PMID:Longitudinal changes in physiological, radiological, and health status measurements in alpha(1)-antitrypsin deficiency and factors associated with decline. 1173 27

Computed tomography (CT) has shown that emphysema is more extensive in the inner (core) region than in the outer (rind) region of the lung. It has been suggested that the concentration of emphysematous lesions in the outer rind leads to a better outcome following lung volume reduction surgery (LVRS) because these regions tend to be more surgically accessible. The present study used a recently described, computer-based CT scan analysis to quantify severe emphysema (lung inflation > 10.2 ml gas/g tissue), mild/moderate emphysema (lung inflation = 10.2 to 6.0 ml gas/g tissue), and normal lung tissue (lung inflation < 6.0 ml gas/g tissue) present in the core and rind of the lung in 21 LVRS patients. The results show that the quantification of severe emphysema independently predicts change in maximal exercise response and FEV(1). We conclude that a greater extent of severe emphysema in the rind of the upper lung predicts greater benefit from LVRS because it identifies the lesions most accessible to removal by LVRS.
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PMID:Core to rind distribution of severe emphysema predicts outcome of lung volume reduction surgery. 1175 Nov 73

According to a previously published theoretical model of emphysema, the ratio of RV to TLC (RV/TLC) reflects the size mismatch between the hyperinflated lungs in the disease and the surrounding chest. The model suggests that RV/TLC is an important predictor of improvement in FVC and that increased FVC is an important determinant of increased FEV(1) after lung volume reduction surgery (LVRS). We tested these predictions in 13 patients undergoing LVRS, in whom we made detailed measurements of lung mechanics. Using stepwise regression, we found that RV/TLC was the only preoperative independent predictor of the increase in FVC. Seventy percent of the increase in FEV(1) was attributable to increased FVC, with the remainder due to increased FEV(1)/FVC. In a separate group of 78 LVRS patients evaluated with standard preoperative pulmonary function tests, RV/TLC again was found to correlate with the increase in FVC, and changes in FEV(1) were also due largely to changes in FVC. However, RV/TLC was not predictive of the increase in FEV(1) among the group of 78 patients, because FEV(1)/FVC in patients with a low preoperative RV/TLC often increased despite little change in FVC. These findings support the proposed mechanism for increased FVC following LVRS. They also illustrate the limitations of the model, and suggest further hypotheses for selecting patients who may benefit from surgery.
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PMID:Improvement in spirometry following lung volume reduction surgery: application of a physiologic model. 1177 27

Lung volume reduction surgery (LVRS) can improve the functional capacity of selected patients with severe emphysema. Hypothesized physiologic effects of LVRS include an improvement in right ventricular function, although this has not been investigated in detail. To help clarify this issue, we used fast-thermistor thermodilution at rest and during submaximal upright exercise in 12 patients, before and 6 mo after bilateral LVRS. Preoperatively, all patients had severe airflow obstruction, with a mean FEV(1) of 0.69 L and an RV-to-TLC ratio of 0.67. Six months after LVRS, significant improvements occurred in respiratory function measures (+0.39 L in FEV(1), p < 0.002; and +/- 0.15 in RV/TLC ratio, p < 0.002) and in right ventricular function indexes measured at rest (+0.21 L in cardiac index [CI], p < 0.01; and +3.0 ml in stroke volume, p < 0.01) and during exercise (+0.9 L in CI, p < 0.002; +10.0 ml in stroke volume index, p < 0.002; and +20% in ejection fraction [EF], p < 0.002). A significant correlation was found between pre- to postoperative changes in the EF response to exercise and changes in the RV/TLC ratio (R = -0.68; p = 0.01). We conclude that a significant improvement in right ventricular performance, particularly during exercise, can occur 6 mo after bilateral LVRS.
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PMID:Effect of lung volume reduction surgery for severe emphysema on right ventricular function. 1185 Mar 41

Bronchiolitis obliterans syndrome (BOS) after lung transplantation is a disease of small airways that is currently graded according to a decline in forced expiratory volume in 1 second (FEV(1)) even in single lung transplant recipients in whom native diseased lung may influence lung physiology. The aim of this study was to evaluate the comparative changes in lung function and survival following the onset of BOS in patients with emphysema and patients with idiopathic pulmonary fibrosis (IPF) who have undergone single lung transplantation. We analyzed data from 31 single lung transplant recipients with emphysema and 25 with IPF who were at risk of BOS. There was no difference in the incidence of BOS between the 2 groups (10 patients with emphysema and 6 patients with IPF), but after the onset of BOS the patients with emphysema had a significantly greater median survival (18 months vs 8 months) despite a poorer mean FEV(1) (1.26 liter, 45% predicted vs 2.11 liter, 67% predicted) compared with the IPF group (p < 0.05) and this difference in lung function persisted at death (0.8 liter, 30% predicted vs 1.65 liter, 51% predicted) (p < 0.05). In summary the native lung physiology appears to influence lung function and therefore survival, and this may indicate that the classification of BOS should include disease-specific characteristics.
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PMID:Bronchiolitis obliterans syndrome in single lung transplant recipients--patients with emphysema versus patients with idiopathic pulmonary fibrosis. 1287 56

The lung pathology of severe chronic obstructive pulmonary disease (COPD) has been poorly investigated. We examined surgical specimens obtained from patients with severe (forced expiratory volume in 1 second [FEV(1)] = 29 +/- 3% predicted, n = 9) or mild/no airflow limitation (FEV(1) = 86 +/- 5% predicted, n = 9) and similar smoking history. With histochemical and immunohistochemical methods we quantified the structural changes and the inflammatory cells in small airways and in muscular pulmonary arteries. As compared with smokers with mild/no COPD, smokers with severe COPD had an increased number of leukocytes in the small airways, which showed a positive correlation with the radiologic score of emphysema and with the value of residual volume, and a negative correlation with the values of FEV(1) and carbon monoxide diffusing capacity. The inflammatory process was characterized by an increase in CD8(+) and CD4(+) T-lymphocytes in the airway wall and by an increase in macrophages in the airway epithelium. When all smokers were considered together, the smoking history was correlated with both the airway wall and smooth muscle thickness, suggesting that smoking itself may play a role in the development of structural changes. No structural and cellular differences were observed in pulmonary arteries between smokers with severe COPD and smokers with mild/no COPD. In conclusion, in the small airways of smokers with severe COPD, there is an increased number of leukocytes, which is correlated with reduced expiratory flow, lung hyperinflation, carbon monoxide diffusion impairment, and radiologic emphysema, suggesting a role for this inflammatory response in the clinical progression of the disease.
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PMID:Airway inflammation in severe chronic obstructive pulmonary disease: relationship with lung function and radiologic emphysema. 1209 Nov 79

In 120 patients with severe emphysema evaluated for participation in the National Emphysema Treatment Trial, pulmonary hemodynamics and ventricular function were assessed. Pulmonary function tests were (%predicted): FEV(1) = 27%; residual volume = 224.6%; diffusion capacity = 26.7%. In 90.8% of patients, end-expiratory pulmonary artery mean pressure was > 20 mm Hg; in 61.4%, end-expiratory wedge pressure was > 12 mm Hg. Cardiac index was normal. Mean pulmonary artery pressure correlated inversely with arterial PO(2), and severity of emphysema, and directly with wedge pressure. Multiple stepwise regression revealed that arterial PO(2) was not an independent predictor of mean pulmonary artery pressure. No correlation was found between indices of emphysema severity and PA pressures. Diastolic ventricular pressures were increased without evidence of systolic dysfunction. We conclude that (1) elevations of pulmonary vascular pressures are common, (2) pulmonary hypertension may be related to factors other than hypoxia, (3) pulmonary hypertension does not impair resting systemic O(2) delivery, and (4) elevated cardiac diastolic pressures do not represent systolic dysfunction.
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PMID:Hemodynamic characterization of patients with severe emphysema. 1215 63

This paper examines potential physiological mechanisms responsible for improvement after lung volume reduction surgery (LVRS). In 25 patients (63 +/- 9 yr; 11 men, 14 women), spirometry [forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC)], lung volumes [residual volume (RV) and total lung capacity (TLC)], small airway resistance, recoil pressures, and respiratory muscle contractility (RMC) were measured before and 4-6 mo after LVRS. Data were interpreted to assess how changes in each component of lung mechanics affect overall function. Among responders (DeltaFEV(1) > or = 12%; 150 ml), improvement was primarily due to an increase in FVC, not to FEV(1)-to-FVC ratio. Among nonresponders, FEV(1), FVC, and RV/TLC did not change after surgery, although recoil pressure increased in both groups. Both groups experienced a reduction in RMC after LVRS. In conclusion, LVRS improves function in emphysema by resizing the lung relative to the chest wall by reducing RV. LVRS does not change airway resistance but decreases RMC, which attenuates the potential benefits of LVRS that are generated by reducing RV/TLC. Among nonresponders, recoil pressure increased out of proportion to reduced volume, such that no increase in vital capacity or improvement in FEV(1) occurred.
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PMID:Physiological characterization of variability in response to lung volume reduction surgery. 1239 Oct 64


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