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National Emphysema Treatment Trial (NETT)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT00000606
Recruitment Status : Completed
First Posted : October 28, 1999
Last Update Posted : April 14, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To evaluate the long term efficacy, morbidity and mortality associated with medical therapy with lung volume reduction surgery (LVRS) as compared to medical therapy alone and to define patient selection criteria. The trial, conducted in conjunction with a patient registry, is supported by the NHLBI, the Centers for Medicare and Medicaid Services (CMS), and the Agency for Healthcare Research and Quality (AHRQ).

Condition or disease Intervention/treatment Phase
Emphysema Lung Diseases Lung Diseases, Obstructive Chronic Obstructive Pulmonary Disease Procedure: Lung volume reduction surgery Phase 3

Detailed Description:


LVRS is intended primarily for those patients whose chronic obstructive pulmonary disease (COPD) is predominantly emphysema. Emphysema is characterized anatomically "by abnormal, persistent enlargement of the airspaces distal to the terminal bronchioles, accompanied by the destruction of the airspace walls and without obvious fibrosis". The loss of the lung architecture leads to compressible peripheral airways that close at higher than normal lung volumes (early airway closure). The increased compliance and the air trapping from early closure leads to hyperinflation of the lung, over distention of the chest wall, a flattened, disadvantaged diaphragm, and ventilation-perfusion mismatch. In the 1950s and 1960s, Dr. Otto Brantigan theorized that surgical excision of multiple wedges of lung would reduce lung volumes, thereby restoring the outward elastic pull on the small airways and reduce airway obstruction. Dr. Brantigan reported that the surgical excision of lung tissue resulted in significant clinical improvement in some cases, but mortality was high. With little objective data and high mortality, the procedure did not gain widespread acceptance.

The experience that diaphragmatic and chest wall function could be restored in emphysema with lung transplantation renewed interest in Dr. Brantigan's work. Improvements in surgical technique have opened the possibility of performing surgical excisions of lung tissue. Recent reports on LVRS have shown improvements in FEV1, FVC, TLC, RV and dyspnea and quality of life assessments.

These reports generated enormous excitement among patients and their doctors. Many centers around the country started performing LVRS with the result that hundreds of patients had the procedure, despite the preliminary nature of the results, the lack of rigorous patient selection criteria and the lack of information on long term outcome. Basic questions remain such as which patient should have the surgery, what protocol should be followed, what physiological tests should be obtained, and what is the long term efficacy of the technique on morbidity, mortality, and quality of life. The mechanisms of benefit and the full cardiopulmonary consequences are unknown.

The concept for the trial originated in the NHLBI Workshop on Evaluation and Research in Lung Volume Reduction Surgery. The initiative was reviewed and approved at the May 1996 National Heart, Lung, and Blood Advisory Council meeting. The Requests for Proposals were released in June, 1996.


In the trial, 1218 eligible patients were randomized to receive either medical therapy (610) or medical therapy with LVRS(608). LVRS was performed by median sternotomy or video-assisted thorascopic surgery (VATS). Centers randomized their patients to either a) medical therapy alone versus medical therapy with LVRS by median sternotomy, b) medical therapy alone versus medical therapy with LVRS by VATS, or c) medical therapy alone versus medical therapy with LVRS by median sternotomy versus medical therapy with LVRS by bilateral VATS. Medical therapy included pulmonary rehabilitation and education. Direct comparisons of the two surgical techniques were possible only at the centers that performed both techniques. All arms included intensive pulmonary rehabilitation. The primary endpoints were survival and functional improvement as assessed by maximum workload. Secondary endpoints included morbidity, improvement in pulmonary function, quality of life and performance of activities of daily living. Follow-up exams, including history, physical exams, pulmonary function tests, exercise tests and quality of life assessments, occurred after pre-operative rehabilitation and six and twelve months after surgery and every twelve months thereafter. Recruitment ended July 31, 2002 and follow-up ended in December, 2002.

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Study Type : Interventional  (Clinical Trial)
Allocation: Randomized
Primary Purpose: Treatment
Study Start Date : December 1996
Actual Primary Completion Date : December 2005
Actual Study Completion Date : December 2005

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Emphysema

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 100 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Men and women with end-stage emphysema.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00000606

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
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OverallOfficial: Steven Piantadosi Johns Hopkins University
Study Data/Documents: Individual Participant Data Set  This link exits the ClinicalTrials.gov site
Identifier: NETT
NHLBI provides controlled access to IPD through BioLINCC. Access requires registration, evidence of local IRB approval or certification of exemption from IRB review, and completion of a data use agreement.


Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

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ClinicalTrials.gov Identifier: NCT00000606    
Other Study ID Numbers: 218
First Posted: October 28, 1999    Key Record Dates
Last Update Posted: April 14, 2016
Last Verified: April 2009
Additional relevant MeSH terms:
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Lung Diseases
Lung Diseases, Obstructive
Pulmonary Disease, Chronic Obstructive
Pulmonary Emphysema
Respiratory Tract Diseases
Chronic Disease
Disease Attributes
Pathologic Processes