Abstract
Rationale: Previous investigations have identified several potential predictors of outcomes from lung volume reduction surgery (LVRS). A concern regarding these studies has been their small sample size, which may limit generalizability. We therefore sought to examine radiographic and physiologic predictors of surgical outcomes in a large, multicenter clinical investigation, the National Emphysema Treatment Trial.
Objectives: To identify objective radiographic and physiological indices of lung disease that have prognostic value in subjects with chronic obstructive pulmonary disease being evaluated for LVRS.
Methods: A subset of the subjects undergoing LVRS in the National Emphysema Treatment Trial underwent preoperative high-resolution computed tomographic (CT) scanning of the chest and measures of static lung recoil at total lung capacity (SRtlc) and inspiratory resistance (Ri). The relationship between CT measures of emphysema, the ratio of upper to lower zone emphysema, CT measures of airway disease, SRtlc, Ri, the ratio of residual volume to total lung capacity (RV/TLC), and both 6-month postoperative changes in FEV1 and maximal exercise capacity were assessed.
Measurements and Main Results: Physiological measures of lung elastic recoil and inspiratory resistance were not correlated with improvement in either the FEV1 (R = −0.03, P = 0.78 and R = –0.17, P = 0.16, respectively) or maximal exercise capacity (R = –0.02, P = 0.83 and R = 0.08, P = 0.53, respectively). The RV/TLC ratio and CT measures of emphysema and its upper to lower zone ratio were only weakly predictive of postoperative changes in both the FEV1 (R = 0.11, P = 0.01; R = 0.2, P < 0.0001; and R = 0.23, P < 0.0001, respectively) and maximal exercise capacity (R = 0.17, P = 0.0001; R = 0.15, P = 0.002; and R = 0.15, P = 0.002, respectively). CT assessments of airway disease were not predictive of change in FEV1 or exercise capacity in this cohort.
Conclusions: The RV/TLC ratio and CT measures of emphysema and its distribution are weak but statistically significant predictors of outcome after LVRS.
AT A GLANCE COMMENTARY.
Scientific Knowledge on the Subject
Multiple computed tomographic and physiological measures have been investigated as predictors of outcome from lung volume reduction surgery in single sites with small study cohorts. Data collected during the National Emphysema Treatment Trial allow replication of these studies in a large, well-characterized cohort of subjects with severe emphysema.
What This Study Adds to the Field
Lung recoil and inspiratory resistance were not predictive of surgical outcomes. The residual volume–to–total lung capacity ratio and ratio of upper to lower zone emphysema on computed tomography scan were statistically significantly correlated with improvement in lung function and exercise capacity; however, the magnitude of these correlations limits their use in clinical care.
Lung volume reduction surgery (LVRS) has been demonstrated to be one of the limited therapeutic options that can reduce both morbidity and mortality for selected subjects with severe chronic obstructive pulmonary disease (COPD) (1, 2). However, identifying which subjects will experience the greatest benefit from such intervention and therefore have the best risk-to-benefit ratio for undergoing such a procedure has posed a challenge to clinicians. In the National Emphysema Treatment Trial (NETT), upper lobe–predominant emphysema on computed tomographic (CT) imaging and low exercise capacity were two independent characteristics that identified subjects most likely to have a reduction in mortality as a result of surgery (2). Further work to identify computed tomographic and physiological predictors of surgical outcomes in this cohort has been limited. Identification of additional preoperative predictive measures of subject benefit and ultimately the integration of these measures into a preprocedure assessment that included regional distribution of emphysema and exercise capacity would further optimize patient selection for LVRS.
At the time of enrollment, subjects participating in NETT underwent high-resolution CT scanning of the chest in which quantitative measures of airway disease could be performed. An additional subset of these subjects underwent detailed measures of lung physiology including static lung recoil at total lung capacity (SRtlc) and lung inspiratory resistance (Ri), both of which have been independently evaluated as predictors of surgical outcomes after lung volume reduction (3, 4). We hypothesized that specific physiological and radiographic metrics of airway and parenchymal structure may refine the ability to predict outcomes from LVRS.
METHODS
Clinical Assessment
All subjects enrolled in the NETT underwent lung function testing including pre- and postbronchodilator spirometry and lung volume measurement (2). Computed tomographic images of the chest were acquired at full inflation with a minimum of 200 mA · seconds and reconstructed using a high spatial frequency algorithm, 1- to 2-mm collimation at 20-mm intervals. Densitometric assessments of the burden of emphysema were performed by the NETT Image Analysis Center (IAC) at the University of Iowa (Iowa City, IA), using a Hounsfield unit (HU) threshold of −950 (%low attenuation area less than −950 HU) as described previously (5, 6). Quantitative measures of emphysema were calculated for both the whole lung and upper, middle, and lower thirds. In the latter case, these regions were defined by equal divisions in cranial–caudal lung height. Discrete measures of airway wall thickness were performed with Airway Inspector (www.AirwayInspector.org) at Brigham and Women's Hospital (Boston, MA) in manually selected airways in the right and left upper lobes and right lower lobes, using the phase congruency method for airway wall segmentation (7). From these measures, the square root of the wall area of a 10-mm lumenal perimeter (Pi10) airway was calculated as described previously (8). In this way, a subject's CT burden of airway disease could be expressed by a single metric. Additional demographic data such as subject age, sex, and smoking history were collected and available for analysis.
Lung Physiology: Lung Static Recoil and Lung Inspiratory Resistance
Five of the NETT clinical centers participated in the lung physiology substudy. Measurement of SRtlc and lung Ri was performed with an esophageal balloon to measure esophageal pressure as an approximation of pleural pressure (9). This was inserted through the nares to a depth of approximately 40 cm and then inflated with 0.5 cm3 of air. Proper balloon placement was confirmed by observing a negligible change in transpulmonary pressure (Ptp) with respiratory efforts made against an occluded airway. Transpulmonary pressures were calculated by simultaneously recording pressure at the airway opening and esophagus (Ptp = Pao – Pes). Gas flow was measured with a pneumotachometer placed at the mouth. A single measure of lung inspiratory resistance was calculated by the methods previously outlined by Ingenito and colleagues (4). Transpulmonary pressure at full inflation was designated as static lung recoil at TLC (SRtlc). Measures of SRtlc were calculated as the average of up to three subject efforts.
Definition of Outcomes after LVRS
The primary outcomes after LVRS used in this investigation were the observed changes in a subject's FEV1 and maximal work attained on exercise testing at the 6-month postoperative interval. A secondary outcome was the 6-month postoperative change in the University of California, San Diego (San Diego, CA) Shortness of Breath Questionnaire (UCSD SOBQ) total score. A reduction in the UCSD SOBQ total score equates with a reduction in a subject's sense of breathlessness. In all cases, these changes were calculated as the algebraic difference between the values collected 6 months after enrollment and baseline measures made after pulmonary rehabilitation.
Statistical Analysis
All data are presented as means ± SD. Upper to lower lung zone ratios of emphysema were calculated by dividing the percent emphysema in the upper zone by the percent emphysema in the lower zone. Spearman correlation coefficients were used to express the strength of the relationships between CT measures of emphysema and airway disease, lung function, and lung mechanics at the time of study enrollment. The 6-month postoperative changes in both FEV1 and maximal exercise capacity were examined by univariate and multivariate correlative analysis to these baseline metrics of lung mechanics and both CT emphysema and airway disease. P values less than 0.05 were considered statistically significant. Statistical analysis was performed with SAS version 9.0 (SAS, Cary, NC).
RESULTS
This analysis was limited to the surgical arm of NETT (n = 608), members of had baseline measurement of lung function, exercise capacity, and questionnaire-based assessments of dyspnea (Table 1). The mean FEV1% predicted was 26.8 ± 7.4, with a mean residual volume–to–total lung capacity (RV/TLC) ratio of 0.64 ± 0.08, mean maximal work of 38.7 ± 21.1 W, and a mean preoperative UCSD SOBQ total score of 61.6 ± 18.1. Whole lung and regional densitometric measures of emphysema were available for 546 subjects. The mean percent emphysema by CT was 15.9 ± 10.9% and the mean ratio of upper to lower lung zone emphysema was 9.9 ± 43.5. Additional quantitative airway analysis was performed on the CT scans of 187 subjects from the NETT Genetics Ancillary Study (2). These measures were expressed as the square root of the wall area of a derived airway with a lumen perimeter of 10 mm (Pi10) and the mean value was 5.1 ± 0.6 mm (8).
TABLE 1.
BASELINE DATA FOR NATIONAL EMPHYSEMA TREATMENT TRIAL SURGICAL COHORT COLLECTED AFTER PULMONARY REHABILITATION
| Parameter | Mean (SD) |
|---|---|
| Age, years | 66.7 (6.3) |
| Sex, male | 355 or 58% |
| FEV1% predicted | 26.8 (7.4) |
| Maximum work, W | 38.7 (21.1) |
| UCSD SOBQ score (n = 608) | 61.6 (18.1) |
| Percent emphysema (%LAA-950) (n = 546) | 15.9 (10.9) |
| Emphysema ratio (n = 546) | 9.9 (43.5) |
| Inspiratory resistance, Ri (n = 85) | 7.3 (4.1) |
| Lung static recoil (n = 115) | 9.0 (4.1) |
| Square root of wall area (n = 187) | 5.1 (0.6) |
Definition of abbreviations: %LAA-950 = percentage low-attenuation area (less than −950 Hounsfield units); UCSD SOBQ = University of California, San Diego Shortness of Breath Questionnaire.
Unless otherwise indicated, data are provided for 608 subjects.
Across the 5 centers participating the lung physiology substudy, a total of 115 subjects underwent measures of SRtlc (mean, 9.0 ± 4.1 cm H2O) and 85 subjects underwent measures of Ri (mean, 7.3 ± 4.1 cm H2O/L/s). The number of subjects enrolled by center is provided in Table 2 and the overall distribution of data collection in the surgical cohort is shown in Figure 1.
TABLE 2.
DISTRIBUTION OF SUBJECT ENROLLMENT BY CLINICAL CENTER FOR LUNG PHYSIOLOGY SUBSTUDY
| Center | Static Recoil (SRtlc) | Inspiratory Resistance (Ri) |
|---|---|---|
| Baylor College of Medicine | 28 | 29 |
| Brigham and Women's Hospital | 30 | 30 |
| Columbia University | 6 | 6 |
| National Jewish Medical and Research Center | 20 | 20 |
| Temple University | 31 | 0 |
Values represent the number of subjects enrolled at each center who underwent measures of SRtlc and Ri.
Figure 1.
Schematic depiction of preoperative data collected from the surgical cohort. CT = computed tomography; LVRS = lung volume reduction surgery; UCSD = University of California, San Diego Shortness of Breath Questionnaire.
Baseline Measures of Lung Function: Surgical Cohort
In univariate analysis, the RV/TLC ratio was inversely correlated with both baseline FEV1% predicted (R = –0.50, P < 0.0001) and maximal exercise capacity (R = −0.53, P < 0.0001). CT emphysema was weakly correlated with FEV1% predicted (R = −0.1, P = 0.02) and exercise capacity (R = –0.1, P = 0.02) but the ratio of upper to lower zone emphysema was not (FEV1% predicted: R = 0.006, P = 0.90; maximal exercise capacity: R = 0.03, P = 0.50). Lung Ri was of significant correlative value for both a subject's FEV1% predicted (R = −0.25, P = 0.02) and maximal exercise capacity (R = −0.48, P < 0.0001) at study enrollment. Static lung recoil at TLC (SRtlc) was not predictive of either a subject's FEV1% predicted (R = 0.04, P = 0.66) or maximal exercise capacity (R = 0.005, P = 0.96).
Six-month Change in Lung Function after LVRS
Six months after LVRS, the mean change in FEV1 for the 495 subjects for whom data were available was 200 ± 240 ml. Within this group, 480 subjects underwent additional exercise testing with a mean improvement of 5.4 ± 14.6 W (Table 3).
TABLE 3.
SIX-MONTH CHANGE IN FUNCTIONAL STATUS OF SURGICAL COHORT
| Parameter | Mean (SD) |
|---|---|
| Δ FEV1, L (n = 495) | 0.2 (0.24) |
| Δ Maximal work, W (n = 480) | 5.4 (14.6) |
| Δ UCSD SOBQ score (n = 507) | −15.5 (22.1) |
Changes in parameters were calculated using the measure collected at 6 months minus that collected at baseline.
Data are presented as means and standard deviation.
Physiological Predictors of Surgical Outcome
The preoperative RV/TLC ratio was weakly correlated to both an improvement in FEV1% predicted (R = 0.11, P = 0.01) and change in maximal exercise capacity (R = 0.17, P = 0.0001). There was no relationship between preoperative measures of either lung Ri or lung SRtlc for either the postoperative change in FEV1 (R = −0.17, P = 0.16 and R = −0.03, P = 0.78, respectively—results depicted graphically in Figures 2 and 3) or the postoperative change in exercise capacity (R = 0.08, P = 0.53 and R = −0.02, P = 0.83, respectively).
Figure 2.
Graphical relationship between a subject's baseline inspiratory resistance (Ri) and their 6-month change in FEV1 after lung volume reduction surgery.
Figure 3.
Graphical relationship between a subject's baseline static recoil at total lung capacity (SRtlc) and their 6-month change in FEV1 after lung volume reduction surgery.
Computed Tomographic Predictors of Surgical Outcome
Within the surgical cohort, both the baseline burden of CT emphysema (Figure 4) and ratio of upper to lower zone emphysema were weakly predictive of a subject's change in FEV1 (R = 0.20, P < 0.0001 and R = 0.23, P < 0.0001, respectively) and change in maximal exercise capacity (R = 0.15, P = 0.002 and R = 0.15, P = 0.002, respectively). When the RV/TLC ratio, and both CT emphysema and its upper to lower zone ratio, were included in a multivariate model, only the ratio of upper to lower emphysema remained a significant predictor of a subject's change in FEV1 (P = 0.0001, model R2 = 0.16). When using this same model to predict postoperative improvement in maximal exercise capacity, both the RV/TLC ratio and emphysema ratio remained significant (P = 0.001 and P < 0.0001, respectively; model R2 = 0.15). Finally, in a subset of 177 subjects (only 177 of the original 187 subjects had follow-up lung function testing at 6 mo), CT airway wall thickness (square root wall area of Pi10) was not predictive of either the 6-month change in FEV1 (R = −0.06, P = 0.43) or 6-month change in maximal work (R = 0.004, P = 0.95).
Figure 4.
Relationship of the change in FEV1 (value at 6-mo baseline value) and preoperative percent emphysema (%LAA-950; percentage low-attenuation area [less than −950 Hounsfield units]) as measured from baseline computed tomography scans.
Predictors of 6-month Change in the UCSD SOBQ Total Score
Six months after LVRS, the mean reduction in UCSD SOBQ total score (signifying an improvement in symptoms) was 15.3 ± 22.1. Within this cohort, preoperative Ri (R = −0.09, P = 0.48), the total burden of emphysema (R = −0.04, P = 0.35), and the subject's preoperative SRtlc (R = −0.11, P = 0.32) were not predictive of improvement in subject symptoms. The preoperative RV/TLC ratio and ratio of upper to lower zone emphysema were both related to a reduction in UCSD SOBQ score at 6 months (R = −0.14, P = 0.02 and R = −0.20, P < 0.0001, respectively), suggesting that those subjects with the highest baseline RV/TLC ratio and highest preoperative ratio of upper to lower lung zone emphysema on their CT scan experienced the greatest improvement in symptoms 6 months after LVRS. A subject's improvement in both FEV1 and maximal exercise capacity was correlated with the reduction in dyspnea (R = −0.41, P < 0.0001 and R = −0.5, P < 0.0001, respectively) as assessed by the UCSD SOBQ.
DISCUSSION
Using data from the National Emphysema Treatment Trial, we sought to determine whether detailed physiological assessment of lung function and preoperative high-resolution CT scans of the chest could be used to predict postoperative changes in lung function, exercise capacity, and symptoms of breathlessness. Included in this analysis were the RV/TLC ratio (10, 11) and measures of both the lung static recoil at TLC and lung inspiratory resistance (3, 4). Additional objective CT measures of airway disease as well as both global and regional assessments of emphysema were also used. When examining these metrics on univariate analysis, the baseline RV/TLC ratio and CT measures of emphysema and its distribution were weakly predictive of post-LVRS improvements in lung function and exercise capacity. Further, when adjusted for the total amount of CT emphysema present, only the magnitude of the ratio of upper to lower zone emphysema remained as a significant predictor of 6-month change in a subject's FEV1. Using a similar model, both the RV/TLC and ratio of upper to lower zone emphysema were predictive of change in maximal exercise capacity after LVRS. The preoperative RV/TLC ratio and ratio of upper to lower zone emphysema were both directly related to improvement in symptoms of breathlessness after LVRS.
The lack of correlation between the lung static recoil and either baseline lung function or postoperative change in FEV1 is consistent with prior observations (4, 12). Preoperative lung inspiratory resistance was, however, expected to be inversely correlated with postoperative improvement in lung function. Those subjects with the highest Ri and therefore the greatest burden of airway disease were expected to have the least functional improvement after LVRS (4). We were unable to confirm this previously demonstrated relationship and, although our findings may suggest that such physiological measures are not predictive of surgical outcomes, it is also possible that this finding is in part due to the difficulties in standardizing physiological data collection across several institutions. Between each NETT center that performed measures of Ri, mean values varied between approximately 3 and 10 cm H2O/L/second. Given the homogeneity of the cohort as a whole, it is unlikely that this difference in Ri reflects true center-to-center variance in subject characteristics. When examining the data from a single center (Brigham and Women's Hospital), the cohort size and distribution of Ri measures (mean Ri, 10.0 ± 4.2 cm H2O/L/s) was similar to that published previously (4), and in this NETT cohort, there was no relationship between preoperative Ri and postoperative improvement in FEV1 (R = 0.03, P = 0.88). It should, however, be noted that the cohort members originally described by Ingenito and colleagues (4) were somewhat younger, had more severe airflow obstruction, less hyperinflation, and different radiographic selection criteria than did NETT participants.
Computed tomographic measures of airspace but not airway disease were found to be predictive of postoperative changes in both lung function and maximal exercise capacity. More specifically, when adjusted for the total amount of emphysema, only the objective ratio of upper to lower zone emphysema on preoperative CT scans was predictive of postoperative improvement. In the original NETT publication, semiquantitative visual determinations of the regional burden of emphysema were found to predict mortality where those subjects with upper zone–predominant disease would have the best chances of experiencing a survival advantage from LVRS (2). Since that time there has been increasing recognition of the interobserver variability in such measures and the potential strength of using objective densitometric measures of emphysema has been emphasized (13). The results of the current investigation suggest that objective measures of the ratio of upper to lower zone emphysema are statistically correlated with surgical outcomes such as improvement in both FEV1 and maximal exercise capacity. The strength of these observed relationships, however, tempers their use in clinical medicine. These findings are consistent with prior studies such as that reported by Nakano and colleagues, in which the objective ratio of rind to core burden of emphysema in the upper regions of the lung of 21 subjects could be used as a predictor of postoperative improvement in FEV1 and exercise capacity (14). Although the study by Nakano and colleagues was one of the first to objectively examine the distribution of emphysema in subjects undergoing LVRS, additional investigations have reported that both semiobjective measures of disease distribution and quantitative measures of total burden of emphysema could be used as predictors of functional improvement (15–17).
Prior work by Ingenito and colleagues suggests that a subject's burden of airway disease influences outcomes from LVRS (4). On the basis of the reported correlation between CT measures of proximal airways and distal small airway disease (18), we expected to find that those subjects with thicker airway walls on CT scan would experience less functional benefit from LVRS. There was, in fact, no relationship between these measures. The inclusion criteria for NETT, severe COPD and emphysema on CT scan, led to a cohort with emphysema-predominant COPD. This homogeneity of the study cohort and the limited data available in the CT scans may have obscured any such relationship if it existed. An alternative explanation is that there is a predictive relationship between CT measures of airway disease and functional outcomes after LVRS and the metric employed in this investigation, the derived square root of the wall area of a 10-mm lumenal perimeter airway, is insensitive to regional burdens of airway disease. For example, a subject with upper zone–predominant emphysema and airway disease may fare better from upper zone volume reduction than a subject with a similar distribution of emphysema but lower zone–predominant airway disease. Such regional discrimination of airway disease and emphysema may have important prognostic implications for such techniques as endoscopic lung volume reduction (19–21). In either case, the age of the CT data and, more specifically, the older generation of CT scanners employed in this investigation with the interval spacing in the reconstructed images limited our analysis and ability to correlate radiographic airway disease and surgical outcomes.
A subject's preoperative RV/TLC ratio was predictive of postoperative improvement in breathlessness. Specifically, those subjects with the greatest hyperinflation on pulmonary function testing experienced the greatest procedurally related symptomatic benefit. Also, computed tomographic measures of a subject's distribution of emphysema but not its absolute burden was correlated with a subject's reduction in dyspnea after surgery. The explanations for these associates are likely found through the stated relationships between these measures and 6-month changes in lung function and exercise capacity.
There are limitations to this investigation that must be acknowledged, including the age of the CT scans undergoing evaluation and the previously mentioned potential difficulty in standardizing measures of lung physiology across multiple centers. In addition, despite this being one of the largest and well-characterized cohorts of subjects with severe emphysema, there was only limited overlap between the CT scans available for objective analysis and measures of both lung elastic recoil and inspiratory resistance.
In summary, objective computed tomography–based measures of emphysema and its upper to lower zone distribution may be predictive of a subject's response to LVRS as assessed by change in lung function and maximal exercise capacity. CT measures of airway disease and physiological measures of lung elastic recoil and inspiratory resistance do not appear to have similar prognostic value. Contrary to earlier reports, Ri did not predict improvement in pulmonary function or exercise capacity in one of the largest and well-characterized cohorts of subjects with severe emphysema. LVRS is a procedure that can improve quality of life and survival, but only in a highly select group of patients that require careful preoperative physiological and radiologic characterization. This study highlights the complexities of phenotyping patients with COPD. Clearly further investigation is required and a deeper understanding of the pathophysiology of emphysema and its seemingly unpredictable mechanical properties will almost certainly improve clinical decision-making for subjects with severe COPD.
Acknowledgments
NETT Credit Roster Members of the NETT Research Group
Office of the Chair of the Steering Committee, University of Pennsylvania, Philadelphia, PA: Alfred P. Fishman, M.D. (Chair); Betsy Ann Bozzarello; Ameena Al-Amin.
Clinical Centers
Baylor College of Medicine, Houston, TX: Marcia Katz, M.D. (Principal Investigator); Carolyn Wheeler, R.N., B.S.N. (Principal Clinic Coordinator); Elaine Baker, R.R.T., R.P.F.T.; Peter Barnard, Ph.D., R.P.F.T.; Phil Cagle, M.D.; James Carter, M.D.; Sophia Chatziioannou, M.D.; Karla Conejo-Gonzales; Kimberly Dubose, R.R.T.; John Haddad, M.D.; David Hicks, R.R.T., R.P.F.T.; Neal Kleiman, M.D.; Mary Milburn-Barnes, C.R.T.T.; Chinh Nguyen, R.P.F.T.; Michael Reardon, M.D.; Joseph Reeves-Viets, M.D.; Steven Sax, M.D.; Amir Sharafkhaneh, M.D.; Owen Wilson, Ph.D.; Christine Young, P.T.; Rafael Espada, M.D. (Principal Investigator, 1996–2002); Rose Butanda (1999–2001); Minnie Ellisor (2002); Pamela Fox, M.D. (1999–2001); Katherine Hale, M.D. (1998–2000); Everett Hood, R.P.F.T. (1998– 2000); Amy Jahn (1998–2000); Satish Jhingran, M.D. (1998–2001); Karen King, R.P.F.T. (1998–1999); Charles Miller III, Ph.D. (1996–1999); Imran Nizami, M.D. (Co-Principal Investigator, 2000–2001); Todd Officer (1998–2000); Jeannie Ricketts (1998–2000); Joe Rodarte, M.D. (Co-Principal Investigator, 1996–2000); Robert Teague, M.D. (Co-Principal Investigator, 1999–2000); Kedren Williams (1998–1999).
Brigham and Women's Hospital, Boston, MA: John Reilly, M.D. (Principal Investigator); David Sugarbaker, M.D. (Co-Principal Investigator); Carol Fanning, R.R.T. (Principal Clinic Coordinator); Simon Body, M.D.; Sabine Duffy, M.D.; Vladmir Formanek, M.D.; Anne Fuhlbrigge, M.D.; Philip Hartigan, M.D.; Sarah Hooper, E.P.; Andetta Hunsaker, M.D.; Francine Jacobson, M.D.; Marilyn Moy, M.D.; Susan Peterson, R.R.T.; Roger Russell, M.D.; Diane Saunders; Scott Swanson, M.D. (Co-Principal Investigator, 1996–2001).
Cedars-Sinai Medical Center, Los Angeles, CA: Rob McKenna, M.D. (Principal Investigator); Zab Mohsenifar, M.D. (Co-Principal Investigator); Carol Geaga, R.N. (Principal Clinic Coordinator); Manmohan Biring, M.D.; Susan Clark, R.N., M.N.; Jennifer Cutler, M.D.; Robert Frantz, M.D.; Peter Julien, M.D.; Michael Lewis, M.D.; Jennifer Minkoff-Rau, M.S.W.; Valentina Yegyan, B.S., C.P.F.T.; Milton Joyner, B.A. (1996–2002).
Cleveland Clinic Foundation, Cleveland, OH: Malcolm DeCamp, M.D. (Principal Investigator); James Stoller, M.D. (Co-Principal Investigator); Yvonne Meli, R.N.C. (Principal Clinic Coordinator); John Apostolakis, M.D.; Darryl Atwell, M.D.; Jeffrey Chapman, M.D.; Pierre DeVilliers, M.D.; Raed Dweik, M.D.; Erik Kraenzler, M.D.; Rosemary Lann, L.I.S.W.; Nancy Kurokawa, R.R.T., C.P.F.T.; Scott Marlow, R.R.T.; Kevin McCarthy, R.C.P.T.; Priscilla McCreight, R.R.T., C.P.F.T.; Atul Mehta, M.D.; Moulay Meziane, M.D.; Omar Minai, M.D.; Mindi Steiger, R.R.T.; Kenneth White, R.P.F.T.; Janet Maurer, M.D. (Principal Investigator, 1996–2001); Terri Durr, R.N. (2000–2001); Charles Hearn, D.O. (1998–2001); Susan Lubell, P.A.-C. (1999–2000); Peter O'Donovan, M.D. (1998–2003); Robert Schilz, D.O. (1998–2002).
Columbia University, New York, NY in consortium with Long Island Jewish Medical Center, New Hyde Park, NY: Mark Ginsburg, M.D. (Principal Investigator); Byron Thomashow, M.D. (Co-Principal Investigator); Patricia Jellen, M.S.N., R.N. (Principal Clinic Coordinator); John Austin, M.D.; Matthew Bartels, M.D.; Yahya Berkmen, M.D.; Patricia Berkoski, M.S., R.R.T. (Site Coordinator, L.I.J.); Frances Brogan, M.S.N., R.N.; Amy Chong, B.S., C.R.T.; Glenda DeMercado, B.S.N.; Angela DiMango, M.D.; Sandy Do, M.S., P.T.; Bessie Kachulis, M.D.; Arfa Khan, M.D.; Berend Mets, M.D.; Mitchell O'Shea, B.S., R.T., C.P.F.T.; Gregory Pearson, M.D.; Leonard Rossoff, M.D.; Steven Scharf, M.D., Ph.D. (Co-Principal Investigator, 1998–2002); Maria Shiau, M.D.; Paul Simonelli, M.D.; Kim Stavrolakes, M.S., P.T.; Donna Tsang, B.S.; Denise Vilotijevic, M.S., P.T.; Chun Yip, M.D.; Mike Mantinaos, M.D. (1998–2001); Kerri McKeon, B.S., R.R.T., R.N. (1998–1999); Jacqueline Pfeffer, M.P.H., P.T. (1997–2002).
Duke University Medical Center, Durham, NC: Neil MacIntyre, M.D. (Principal Investigator); R. Duane Davis, M.D. (Co-Principal Investigator); John Howe, R.N. (Principal Clinic Coordinator); R. Edward Coleman, M.D.; Rebecca Crouch, R.P.T.; Dora Greene; Katherine Grichnik, M.D.; David Harpole, Jr., M.D.; Abby Krichman, R.R.T.; Brian Lawlor, R.R.T.; Holman McAdams, M.D.; John Plankeel, M.D.; Susan Rinaldo-Gallo, M.E.D.; Sheila Shearer, R.R.T.; Jeanne Smith, A.C.S.W.; Mark Stafford-Smith, M.D.; Victor Tapson, M.D.; Mark Steele, M.D. (1998–1999); Jennifer Norten, M.D. (1998–1999).
Mayo Foundation, Rochester, MN: James Utz, M.D. (Principal Investigator); Claude Deschamps, M.D. (Co-Principal Investigator); Kathy Mieras, C.C.R.P. (Principal Clinic Coordinator); Martin Abel, M.D.; Mark Allen, M.D.; Deb Andrist, R.N.; Gregory Aughenbaugh, M.D.; Sharon Bendel, R.N.; Eric Edell, M.D.; Marlene Edgar; Bonnie Edwards; Beth Elliot, M.D.; James Garrett, R.R.T.; Delmar Gillespie, M.D.; Judd Gurney, M.D.; Boleyn Hammel; Karen Hanson, R.R.T.; Lori Hanson, R.R.T.; Gordon Harms, M.D.; June Hart; Thomas Hartman, M.D.; Robert Hyatt, M.D.; Eric Jensen, M.D.; Nicole Jenson, R.R.T.; Sanjay Kalra, M.D.; Philip Karsell, M.D.; Jennifer Lamb; David Midthun, M.D.; Carl Mottram, R.R.T.; Stephen Swensen, M.D.; Anne-Marie Sykes, M.D.; Karen Taylor; Norman Torres, M.D.; Rolf Hubmayr, M.D. (1998–2000); Daniel Miller, M.D. (1999–2002); Sara Bartling, R.N. (1998–2000); Kris Bradt (1998–2002).
National Jewish Medical and Research Center, Denver, CO: Barry Make, M.D. (Principal Investigator); Marvin Pomerantz, M.D. (Co-Principal Investigator); Mary Gilmartin, R.N., R.R.T. (Principal Clinic Coordinator); Joyce Canterbury; Martin Carlos; Phyllis Dibbern, P.T.; Enrique Fernandez, M.D.; Lisa Geyman, M.S.P.T.; Connie Hudson; David Lynch, M.D.; John Newell, M.D.; Robert Quaife, M.D.; Jennifer Propst, R.N.; Cynthia Raymond, M.S.; Jane Whalen-Price, P.T.; Kathy Winner, O.T.R.; Martin Zamora, M.D.; Reuben Cherniack, M.D. (Principal Investigator, 1997–2000).
Ohio State University, Columbus, OH: Philip Diaz, M.D. (Principal Investigator); Patrick Ross, M.D. (Co-Principal Investigator); Tina Bees (Principal Clinic Coordinator); Jan Drake; Charles Emery, Ph.D.; Mark Gerhardt, M.D., Ph.D.; Mark King, M.D.; David Rittinger; Mahasti Rittinger.
Saint Louis University, Saint Louis, MO: Keith Naunheim, M.D. (Principal Investigator); Robert Gerber, M.D. (Co-Principal Investigator); Joan Osterloh, R.N., M.S.N. (Principal Clinic Coordinator); Susan Borosh; Willard Chamberlain, D.O.; Sally Frese; Alan Hibbit; Mary Ellen Kleinhenz, M.D.; Gregg Ruppel; Cary Stolar, M.D.; Janice Willey; Francisco Alvarez, M.D. (Co-Principal Investigator, 1999–2002); Cesar Keller, M.D. (Co-Principal Investigator, 1996–2000).
Temple University, Philadelphia, PA: Gerard Criner, M.D. (Principal Investigator); Satoshi Furukawa, M.D. (Co-Principal Investigator); Anne Marie Kuzma, R.N., M.S.N. (Principal Clinic Coordinator); Roger Barnette, M.D.; Neil Brister, M.D.; Kevin Carney, R.N., C.C.T.C.; Wissam Chatila, M.D.; Francis Cordova, M.D.; Gilbert D'Alonzo, D.O.; Michael Keresztury, M.D.; Karen Kirsch; Chul Kwak, M.D.; Kathy Lautensack, R.N., B.S.N.; Madelina Lorenzon, C.P.F.T.; Ubaldo Martin, M.D.; Peter Rising, M.S.; Scott Schartel, M.D.; John Travaline, M.D.; Gwendolyn Vance, R.N., C.C.T.C.; Phillip Boiselle, M.D. (1997–2000); Gerald O'Brien, M.D. (1997–2000).
University of California, San Diego, San Diego, CA: Andrew Ries, M.D., M.P.H. (Principal Investigator); Robert Kaplan, Ph.D. (Co-Principal Investigator); Catherine Ramirez, B.S., R.C.P. (Principal Clinic Coordinator); David Frankville, M.D.; Paul Friedman, M.D.; James Harrell, M.D.; Jeffery Johnson; David Kapelanski, M.D.; David Kupferberg, M.D., M.P.H.; Catherine Larsen, M.P.H.; Trina Limberg, R.R.T.; Michael Magliocca, R.N., C.N.P.; Frank J. Papatheofanis, M.D., Ph.D.; Dawn Sassi-Dambron, R.N.; Melissa Weeks.
University of Maryland at Baltimore, Baltimore, MD in consortium with Johns Hopkins Hospital, Baltimore, MD: Mark Krasna, M.D. (Principal Investigator); Henry Fessler, M.D. (Co-Principal Investigator); Iris Moskowitz (Principal Clinic Coordinator); Timothy Gilbert, M.D.; Jonathan Orens, M.D.; Steven Scharf, M.D., Ph.D.; David Shade; Stanley Siegelman, M.D.; Kenneth Silver, M.D.; Clarence Weir; Charles White, M.D.
University of Michigan, Ann Arbor, MI: Fernando Martinez, M.D. (Principal Investigator); Mark Iannettoni, M.D. (Co-Principal Investigator); Catherine Meldrum, B.S.N., R.N., C.C.R.N. (Principal Clinic Coordinator); William Bria, M.D.; Kelly Campbell; Paul Christensen, M.D.; Kevin Flaherty, M.D.; Steven Gay, M.D.; Paramjit Gill, R.N.; Paul Kazanjian, M.D.; Ella Kazerooni, M.D.; Vivian Knieper; Tammy Ojo, M.D.; Lewis Poole; Leslie Quint, M.D.; Paul Rysso; Thomas Sisson, M.D.; Mercedes True; Brian Woodcock, M.D.; Lori Zaremba, R.N.
University of Pennsylvania, Philadelphia, PA: Larry Kaiser, M.D. (Principal Investigator); John Hansen-Flaschen, M.D. (Co-Principal Investigator); Mary Louise Dempsey, B.S.N., R.N. (Principal Clinic Coordinator); Abass Alavi, M.D.; Theresa Alcorn, Selim Arcasoy, M.D.; Judith Aronchick, M.D.; Stanley Aukberg, M.D.; Bryan Benedict, R.R.T.; Susan Craemer, B.S., R.R.T., C.P.F.T.; Ron Daniele, M.D.; Jeffrey Edelman, M.D.; Warren Gefter, M.D.; Laura Kotler-Klein, M.S.S.; Robert Kotloff, M.D.; David Lipson, M.D.; Wallace Miller, Jr., M.D.; Richard O'Connell, R.P.F.T.; Staci Opelman, M.S.W.; Harold Palevsky, M.D.; William Russell, R.P.F.T.; Heather Sheaffer, M.S.W.; Rodney Simcox, B.S.R.T., R.R.T.; Susanne Snedeker, R.R.T., C.P.F.T.; Jennifer Stone-Wynne, M.S.W.; Gregory Tino, M.D.; Peter Wahl; James Walter, R.P.F.T.; Patricia Ward; David Zisman, M.D.; James Mendez, M.S.N., C.R.N.P. (1997–2001); Angela Wurster, M.S.N., C.R.N.P. (1997–1999).
University of Pittsburgh, Pittsburgh, PA: Frank Sciurba, M.D. (Principal Investigator); James Luketich, M.D. (Co-Principal Investigator); Colleen Witt, M.S. (Principal Clinic Coordinator); Gerald Ayres; Michael Donahoe, M.D.; Carl Fuhrman, M.D.; Robert Hoffman, M.D.; Joan Lacomis, M.D.; Joan Sexton; William Slivka; Diane Strollo, M.D.; Erin Sullivan, M.D.; Tomeka Simon; Catherine Wrona, R.N., B.S.N.; Gerene Bauldoff, R.N., M.S.N. (1997–2000); Manuel Brown, M.D. (1997–2002); Elisabeth George, R.N., M.S.N. (Principal Clinic Coordinator, 1997–2001); Robert Keenan, M.D. (Co-Principal Investigator, 1997–2000); Theodore Kopp, M.S. (1997–1999); Laurie Silfies (1997–2001).
University of Washington, Seattle, WA: Joshua Benditt, M.D. (Principal Investigator), Douglas Wood, M.D. (Co-Principal Investigator); Margaret Snyder, M.N. (Principal Clinic Coordinator); Kymberley Anable; Nancy Battaglia; Louie Boitano; Andrew Bowdle, M.D.; Leighton Chan, M.D.; Cindy Chwalik; Bruce Culver, M.D.; Thurman Gillespy, M.D.; David Godwin, M.D.; Jeanne Hoffman; Andra Ibrahim, M.D.; Diane Lockhart; Stephen Marglin, M.D.; Kenneth Martay, M.D.; Patricia McDowell; Donald Oxorn, M.D.; Liz Roessler; Michelle Toshima; Susan Golden (1998–2000).
Other Participants
Agency for Healthcare Research and Quality, Rockville, MD: Lynn Bosco, M.D., M.P.H.; Yen-Pin Chiang, Ph.D.; Carolyn Clancy, M.D.; Harry Handelsman, D.O.
Centers for Medicare and Medicaid Services, Baltimore, MD: Steven M Berkowitz, Ph.D.; Tanisha Carino, Ph.D.; Joe Chin, M.D.; JoAnna Baldwin; Karen McVearry; Anthony Norris; Sarah Shirey; Claudette Sikora Steven Sheingold, Ph.D. (1997–2004).
Coordinating Center, Johns Hopkins University, Baltimore, MD: Steven Piantadosi, M.D., Ph.D. (Principal Investigator); James Tonascia, Ph.D. (Co-Principal Investigator); Patricia Belt; Amanda Blackford, Sc.M.; Karen Collins; Betty Collison; Ryan Colvin, M.P.H.; John Dodge; Michele Donithan, M.H.S.; Vera Edmonds; Gregory L. Foster, M.A.; Julie Fuller; Judith Harle; Rosetta Jackson; Shing Lee, Sc.M.; Charlene Levine; Hope Livingston; Jill Meinert; Jennifer Meyers; Deborah Nowakowski; Kapreena Owens; Shangqian Qi, M.D.; Michael Smith; Brett Simon, M.D.; Paul Smith; Alice Sternberg, Sc.M.; Mark Van Natta, M.H.S.; Laura Wilson, Sc.M.; Robert Wise, M.D.
Cost Effectiveness Subcommittee: Robert M. Kaplan, Ph.D. (Chair); J. Sanford Schwartz, M.D. (Co-Chair); Yen-Pin Chiang, Ph.D.; Marianne C. Fahs, Ph.D.; A. Mark Fendrick, M.D.; Alan J. Moskowitz, M.D.; Dev Pathak, Ph.D.; Scott Ramsey, M.D., Ph.D.; Steven Sheingold, Ph.D.; A. Laurie Shroyer, Ph.D.; Judith Wagner, Ph.D.; Roger Yusen, M.D.
Cost Effectiveness Data Center, Fred Hutchinson Cancer Research Center, Seattle, WA: Scott Ramsey, M.D., Ph.D. (Principal Investigator); Ruth Etzioni, Ph.D.; Sean Sullivan, Ph.D.; Douglas Wood, M.D.; Thomas Schroeder, MA; Karma Kreizenbeck; Kristin Berry, M.S.; Nadia Howlader, M.S.
CT Scan Image Storage and Analysis Center, University of Iowa, Iowa City, IA: Eric Hoffman, Ph.D. (Principal Investigator); Janice Cook-Granroth, B.S.; Angela Delsing, RT; Junfeng Guo, Ph.D.; Geoffrey McLennan, M.D.; Brian Mullan, M.D.; Chris Piker, B.S.; Joseph Reinhardt, Ph.D.; Blake Wood; Jered Sieren, R.T.R.; William Stanford, M.D.
Data and Safety Monitoring Board: John A. Waldhausen, M.D. (Chair); Gordon Bernard, M.D.; David DeMets, Ph.D.; Mark Ferguson, M.D.; Eddie Hoover, M.D.; Robert Levine, M.D.; Donald Mahler, M.D.; A. John McSweeny, Ph.D.; Jeanine Wiener-Kronish, M.D.; O. Dale Williams, Ph.D.; Magdy Younes, M.D.
Marketing Center, Temple University, Philadelphia, PA: Gerard Criner, M.D. (Principal Investigator); Charles Soltoff, M.B.A.
Project Office, National Heart, Lung, and Blood Institute, Bethesda, MD: Gail Weinmann, M.D. (Project Officer); Joanne Deshler (Contracting Officer); Dean Follmann, Ph.D.; James Kiley, Ph.D.; Margaret Wu, Ph.D. (1996–2001).
Other Acknowledgments
Arthur Gelb, M.D., Lakewood Regional Medical Center, Lakewood, CA.
Supported by NIH grants 5U10HL074428-3, R01HL52586, and 1K23HL089353-01A1, and by a grant from the Parker B. Francis Foundation. Additional sources of funding: The National Emphysema Treatment Trial (NETT) is supported by contracts with the National Heart, Lung, and Blood Institute (N01HR76101, N01HR76102, N01HR76103, N01HR76104, N01HR76105, N01HR76106, N01HR76107, N01HR76108, N01HR76109, N01HR76110, N01HR76111, N01HR76112, N01HR76113, N01HR76114, N01HR76115, N01HR76116, N01HR76118, and N01HR76119), the Centers for Medicare and Medicaid Services (CMS), and the Agency for Healthcare Research and Quality (AHRQ).
Originally Published in Press as DOI: 10.1164/rccm.200906-0911OC on December 3, 2009
Conflict of Interest Statement: G.R.W. received $1,001–$5,000 from MedImmune in consultancy fees; F.J.M. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; E.A.H. received $5,001–$10,000 from QI2 for image protocol advice and oversight, $1,001–$5,000 from AstraZeneca, $1,001–$5,000 from Sanofi-Aventis, and $1,001–$5,000 from Grifols in travel and hotel support, an honorarium for a lecture or both, up to $1,000 from Siemens Medical Systems for travel expenses only, $1,001–$5,000 from Chiesi Pharmaceuticals, $1,001–$5,000 from AstraZeneca, and $1,001–$5,000 from GlaxoSmithKline in lecture fees, holds a patent from the University of Iowa for texture analysis of medical images and a patent from Marval Diagnostics for nanoscale liposomal blood-pool contrast agent, holds more than $100,001 in stock ownership or options from VIDA Diagnostics as the founder and shareholder and $100,001 from Marval Diagnostics in stock ownership or options as the founder and shareholder. E.H. is a founder and shareholder of VIDA Diagnostics, which is commercializing image analysis software, developed in E.H.'s university laboratory, which has been used in this study; S.H.L. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; R.S.J.E. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; A.D. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; F.C.S. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; E.K.S. received $10,001–$50,000 from GlaxoSmithKline and $10,001–$50,000 from AstraZeneca in consultancy fees, $1,001–$5,000 from GlaxoSmithKline, $5,001–$10,000 from AstraZeneca, and $1,001–$5,000 from Bayer in lecture fees, more than $100,001 from GlaxoSmithKline in industry-sponsored grants; M.H. received up to $1,000 from Novartis in consultancy fees, $1,001–$5,000 from CSL Behring for serving on an advisory board, $5,001–$10,000 from GlaxoSmithKline in lecture fees, up to $1,000 from UpToDate in royalties; M.D. received $5,001–$10,000 from Portaero, Inc in consultancy fees, $5,001–$10,000 from PneumRx in lecture fees, and $10,001–$50,000 from PneumRx in industry-sponsored grants; J.J.R. received more than $100,001 from Aeris, Inc in industry-sponsored grants for human clinical trial of bronchoscopic lung volume reduction (funding from 2004 to 2007), up to $1,000 from UpToDate in royalties for content contribution to online text.
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