Patient selection criteria for lung volume reduction surgery

McKenna, Robert J.; Brenner, Matthew; Fischel, Richard; Singh, Narinder; Yoong, Ben; Gelb, Arthur F.; Osann, Kathryn

doi:10.1016/s0022-5223(97)70010-2

Cited by 113 publications

(79 citation statements)

References 18 publications

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“…Many studies have suggested that the best candidates for LVRS are those in whom emphysema is most heterogeneous, with localized target areas composed only of cysts and bullae (20)(21)(22)(23). Consider the effects on RV and TLC after removal of such regions.…”

Section: Increased Vcmentioning

confidence: 99%

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Physiologic Basis for Improved Pulmonary Function after Lung Volume Reduction

Fessler¹,

Scharf²,

Ingenito³

et al. 2008

Proceedings of the American Thoracic Society

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It is not readily apparent how pulmonary function could be improved by resecting portions of the lung in patients with emphysema. In emphysema, elevation in residual volume relative to total lung capacity reduces forced expiratory volumes, increases inspiratory effort, and impairs inspiratory muscle mechanics. Lung volume reduction surgery (LVRS) better matches the size of the lungs to the size of the thorax containing them. This restores forced expiratory volumes and the mechanical advantage of the inspiratory muscles. In patients with heterogeneous emphysema, LVRS may also allow space occupied by cysts to be reclaimed by more normal lung. Newer, bronchoscopic methods for lung volume reduction seek to achieve similar ends by causing localized atelectasis, but may be hindered by the low collateral resistance of emphysematous lung. Understanding of the mechanisms of improved function after LVRS can help select patients more likely to benefit from this approach.Keywords: lung mechanics; emphysema surgery; lung recoil; airflow limitation; respiratory muscles PHYSIOLOGIC BASIS FOR IMPAIRMENT WITH EMPHYSEMAInflammatory changes associated with chronic obstructive pulmonary disease (COPD) initiate the changes in lung mechanical properties that characterize emphysema. Inflammation leads to destruction of elastin, which contributes to lung elasticity, and collagen, which provides tensile strength. Although recent interest has focused on the cellular and molecular mechanisms contributing to emphysema, the study of lung mechanical stresses, one of the earliest postulated causes of emphysema (1), has received less attention. Weakened lung parenchyma is more likely to fracture during respiratory stress, and coalescence of a few alveoli can increase stress on adjacent units in a way that favors formation of large, localized cysts similar to the pattern seen in patients with advanced emphysema (2-4). Effects of Emphysema on Expiratory FlowThese sequelae of inflammation ultimately decrease lung elastic recoil and small airway caliber, contributing to characteristic airflow limitation. The three classic determinants of expiratory flow limitation are lung elastic recoil, the propensity for airways to close, and airway resistance (5). Loss of elastic recoil in emphysema decreases the upstream pressure that drives expiratory flow, thereby decreasing maximal flows at any lung volume. Loss of elastic recoil also increases the unstressed volume of the lung (the volume remaining when elastic recoil is zero). Loss of radial traction on airways from lung parenchyma contributes to airway closure at higher lung volumes (increased trapped volume) because a higher transmural pressure is required to maintain airway patency. In addition, airway caliber at any lung volume is decreased (6). Coexisting small airway inflammation and fibrosis further increase airway resistance (7,8). These changes collectively reduce the rate of lung emptying.The rate of lung emptying may be expressed as its time constant, the time necessary for approximately 63% o...

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Section: Increased Vcmentioning

confidence: 99%

“…Before the National Emphysema Treatment Trial (NETT), some centers selected only patients with heterogeneous emphysema for surgery (21). The NETT has confirmed better functional and symptomatic results in such patients (23).…”

Section: Increased Vcmentioning

confidence: 99%

Physiologic Basis for Improved Pulmonary Function after Lung Volume Reduction

Fessler¹,

Scharf²,

Ingenito³

et al. 2008

Proceedings of the American Thoracic Society

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“…Accurate identification of areas of dead space (i.e., areas of gas trapping) is of paramount importance, and imaging is considered central for identifying target sites for LVR (16). Studies have demonstrated that heterogeneous emphysema, which is predominantly in the upper lung zones, predicts a better response to LVR (3,(17)(18)(19) and that the volume of severe emphysema present before LVR correlates with the magnitude of improvement (20). A scintigraphic ratio of decreased perfusion in the upper to the lower lung regions, however, was not predictive of response to therapy in a large randomized study of LVR (21).…”

Section: Discussionmentioning

confidence: 99%

New ¹³³Xe Gas Trapping Index for Quantifying Severe Emphysema Before Partial Lung Volume Reduction

Mathews¹,

Maurer²,

Steiner³

et al. 2008

J Nucl Med

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Lung volume reduction (LVR) is an effective therapy for endstage emphysema. Preliminary and postprocedure imaging is usually limited to CT for anatomic delineation of the location and severity of the most acutely affected lung zones. The purpose of this study was to investigate the potential of using a new quantitative gas trapping index (GTI) derived from a 133 Xe ventilation scan to assess the severity of emphysema. Methods: Using the equilibration and washout phases of a 133 Xe ventilation study, a GTI was compared with visual National Emphysema Treatment Trial (NETT) CT scoring, semiautomated CT densitometry, and 99m Tc perfusion scintigraphy in 28 patients being evaluated for LVR. The GTI was calculated as the percentage of 133 Xe gas retention in a 3-min washout image compared with the peak equilibrium image for 6 lung zones. Results: The GTI correlated best with the percentage of perfusion (20.39, P , 0.0001) and the CT density scoring with the percentage of severe emphysema (0.36, P , 0.0001). There was less correlation with visual NETT CT scores (0.25, P , 0.001). Conclusion: This GTI, based on widely available 133 Xe imaging, shows good correlation with other quantitative measures of emphysema that are anatomically based. Because this GTI provides a more functional assessment of gas trapping and airway disease, these results suggest that additional study is warranted to investigate its use as a functional measure of emphysema before and after LVR.

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“…[28] reported in 1997 that improvement in poFEV1% and dyspnoea score was more evident in patients aged under 70, although the differences were not statistical significant. A growing number of studies in the recent years have reported an improvement of respiratory function after lobectomy in some patients affected by COPD [29], or at least a minimal impairment of respiratory function indicated by better apoFEV% (actual postoperative) than ppoFEV1% (predicted postoperative) [30].…”

Section: Lung Volume Reduction Era and Its Importance In Lung Cancer mentioning

confidence: 95%