Purpose:
The main objectives of this study are to see if a type of lung surgery, known as lung
reduction surgery, in addition to standard medical treatment improves the quality of life,
lung function, and reduces the high mortality associated with severe emphysema when compared
to standard medical treatment alone. Another goal of this study is to better identify the
patients most likely to benefit from this surgical treatment. The information obtained in
this study is important because lung reduction surgery is being done in several centers
around the country but its long term benefits, if any, over standard medical treatment, are
not known.
Study summary:
Chronic obstructive pulmonary disease is a major cause of mortality and morbidity in the US.
Although medical therapy may delay disability and death, there has been no definitive
therapy to improve pulmonary function in these patients. The resection of emphysematous lung
parenchyma, lung volume reduction surgery (LVRS), has been reported in uncontrolled studies
in highly selected emphysema patients to substantially improve parameters of pulmonary
function, dyspnea, and quality of life. Numerous case series have reported significant
short-term benefits. Current LVRS data regarding outcomes is limited by study design lacking
parallel control groups and lack of long term data.
The main objectives of this proposal are: 1) To study the effects of LVRS in addition to
maximal medical therapy when compared to maximal medical therapy alone in terms of
improvement of physiology and quality of life. 2) To better define preoperative selection
criteria to determine which patients would benefit from this surgical intervention. To
accomplish these objectives, patients who meet clinical criteria and complete a pulmonary
rehabilitation-program will be randomized into 2 groups: 1) Continuing optimal medical care
or 2) bilateral LVRS via median sternotomy in addition to medical therapy.
The Houston Veterans Affairs Medical Center is currently performing LVRS under a protocol
supported by Merit Review funding (1996-200O, Effects of lung volume reduction surgery in
the treatment of severe emphysema) in selected patients with severe emphysema. This
controlled study is designed to determine patient selection criteria, as well as, both the
short and long term benefits of operated and non-operated patients with severe emphysema
receiving maximal medical therapy. Given the strict selection criteria and unexpectedly high
survival in both treatment groups to date, it is unlikely in a study of this size that
survival differences will be detected.
In 1997 the National Heart, Lung, and Blood Institute and Health Care Financing
Administration organized a national registry and a controlled, multicenter clinical trial to
compare bilateral LVRS to maximal medical treatment (NETT, National Emphysema Treatment
Trial).
Both our on-going LVRS study and the NETT have been hindered by an underestimation of the
difficulty in recruiting patients who qualify for this invasive study. Both studies have
evaluated/recruited to date approximately 50% of the projected number of subjects required
to achieve statistical power to draw significant clinical conclusions. In fact, the NIH is
investing additional funds in the national "marketing" of the NETT and LVRS. We believe that
this national marketing effort, as well as changes and enhancement of local recruiting
strategies will allow us to enroll adequate patients for study completion. This controlled
clinical trial will provide data to address crucial clinical and potential economic
implications of this surgical intervention in patients with severe emphysema.
Criteria:
1. Post-bronchodilator FEV I < 40% and > 15% of predicted
2. TLC > 120% of predicted*
3. Carbon monoxide diffusing capacity by the single breath technique (DLCOSB) < 50% of
predicted
4. PaCO2 < 55 mmHg
5. Age 75 years or younger
- TLC will be determined by body plethysmography using slow inspiratory effort to
determine thoracic gas lume because of the overestimation of lung volumes by
high frequency panting in patients with COPD.