Surgery for Emphysema

The role of NETT in emphysema research

Lung volume reduction surgery (LVRS) is one of a long lineage of surgical approaches to emphysema. The reintroduction of this operation in the mid-1990s led to great controversy over the value of the procedure and its long-term outcomes. The National Emphysema Treatment Trial (NETT) represented an historical scientific collaboration of the National Institutes of Health (NIH), the Centers for Medicare and Medicaid Services (CMS), and the Agency for Health Research and Quality (AHRQ). NETT was designed primarily as a pivotal surgical clinical trial, but also incorporated data collection to inform health policy and cost-benefit analyses. NETT faced challenges that included practical and ethical matters, statistical design and analysis issues, and intense public and political scrutiny. The study design required the development of methods for pulmonary rehabilitation, lung imaging, and exercise testing that have become templates for current clinical and research practice. During the course of the trial, the confidential deliberations of the Data and Safety Monitoring Board (DSMB) played an important role in the ultimate success of the trial and protection of research participants. Because of the importance of the NETT outcomes, the results were disseminated to the medical community and transformed into health policy in a rapid and efficient manner. In many ways, the story of NETT serves as a model for evaluation of new surgical approaches to chronic diseases.

Giant bullous lung disease: evaluation, selection, techniques, and outcomes

Patient selection remains one of the most important aspects of successful surgery for bullous disease. Operation is indicated for patients who have incapacitating dyspnea with large bullae that fill more than 30% of the hemithorax and result in the compression of healthy adjacent lung tissue. Operation is also indicated for patients who have complications related to bullous disease such as infection or pneumothorax. Patients who have bullous disease in the presence of diffuse lung disease (emphysematous or nonemphysematous) should be evaluated on an individual basis and surgery should be performed on patients in whom even a small increase in pulmonary function might be of major benefit. Smoking cessation and outpatient pulmonary rehabilitation are required of all patients preoperatively. Patients should undergo PFTs including lung volumes by whole body plethysmography, spirometry, diffusion capacity, and arterial blood gas. CT remains the most important preoperative evaluation because it is useful assessing the extent of bullous disease and the quality of the surrounding lung tissue. The authors favor a minimally invasive technique through VATS whenever possible because it might allow for a quicker recovery and might be associated with less pain than is seen following thoracotomy. Modified Monaldi-type drainage procedures are also effective, especially in high-risk patients who cannot tolerate excisional procedures. Special care must be taken to avoid sacrifice of any potentially functional lung tissue. Lobectomies should be avoided whenever possible. The best results are seen in limited resections of large bullae that spare all surrounding functional pulmonary parenchyma. Postoperative complications are minimized through aggressive tracheobronchial toilet and vigorous chest physiotherapy. Adequate pain control in maintained throughout the postoperative period, initially by way of epidural infusion of morphine or fentanyl and later through oral opioids. Early ambulation and pulmonary rehabilitation also help minimize complications.

Treatment of patients with lung cancer and severe emphysema

The development of lung cancer and emphysema is associated with the destructive chemical milieu that occurs with smoking. The recent interest in lung volume reduction surgery (LVRS) has stimulated a reassessment of the indications for surgery in patients with early stage lung cancer or emphysema. For patients with both diseases, the issues surrounding LVRS are simplified. The major concern is that the lung cancer can be surgically removed without the need for postoperative ventilation or mortality. A secondary consideration is the potential for long-term postoperative respiratory morbidity. These risks can be estimated by evaluating the anatomic location of the tumor, as well as the physiology of the underlying emphysema. Early results of combined LVRS and lung cancer resections suggest a favorable outcome in carefully selected patients.

Lung volume reduction surgery for emphysema: out on a limb without a NETT

Lung volume reduction surgery (LVRS) has recently been rediscovered and offers the potential of improving the quality of life of patients with advanced emphysema. In this article, we discuss the historical and contemporary versions of LVRS. Although initial enthusiasm has been substantial, existing data seem insufficient to demonstrate the safety and efficacy of the procedure in comparison with conventional medical therapy. Fundamental questions remain regarding the long-term effects of an operation versus medical therapy, the optimal selection criteria, the best measures of efficacy, the mechanisms of improvement, the cost-effectiveness of the procedure, and the optimal surgical technique. Until such questions are answered, advising patients about the best management their emphysema will be difficult. The National Emphysema Treatment Trial will address many of these issues and should be embraced by both health-care providers and patients.

Pathologic findings in lung volume reduction surgery

PURPOSE

Lung volume reduction surgery (LVRS) has re-emerged as an alternative in the management of patients with chronic, debilitating, emphysematous lung disease. This has permitted the formal evaluation of pathologic pulmonary changes present in these patients. This study seeks to describe systematically the pathologic findings present in patients undergoing LVRS.

METHODS

Tissue sections stained with hematoxylin-eosin, as well as special stains, were retrospectively reviewed from the specimens of 65 nonconsecutive LVRS patients (male patients, 66%; female patients, 31%; mean age, 63.2+/-6.76 yr). All operations were conducted via an open technique (bilateral, 83%; unilateral, 17%).

RESULTS

Histologic emphysema grade was mild in 9%, moderate in 72%, and severe in 19% of patients. Microscopic bullae were noted in 75% of specimens. Three patients, each with radiographic evidence of a lesion preoperatively, had small (1.1 to 2.8 cm) adenocarcinomas. Granulomatous bronchiolitis and pneumonitis were noted in one patient who postoperatively developed progressive respiratory compromise. An old, inactive aspergilloma was found in the specimen of another patient. Additional findings of potential clinical significance included bronchiolitis (54), bronchiolectasis (6), and bronchoalveolar metaplasia (1). Incidental findings included interstitial fibrosis and scar (55), interstitial inflammation (20), calcification (20), and ossification (11), bone marrow emboli (4), chemodectoma (2), and carcinoid tumorlets (1).

CONCLUSION

This systematic analysis of the resected specimens from patients undergoing LVRS describes a wide range of pathologic findings, including those clinically relevant, as well as incidental. As the application of LVRS continues to expand, the likelihood of discovering clinically significant pathologic lesions (eg, carcinoma) will undoubtedly increase.

Preoperative and postoperative imaging in the surgical management of pulmonary emphysema

For patients with emphysema, imaging studies have been useful for diagnostic purposes and for preoperative patient selection for surgical intervention, such as bullectomy, lung transplantation, and LVRS. Chest radiography is useful in evaluating hyperinflation. Inspiratory and expiratory films are used to estimate diaphragmatic excursion and air-trapping. CT scan is used to evaluate the anatomy and distribution of emphysema throughout the lungs, providing information clinically unobtainable by other means. Both imaging techniques are useful for detecting other disease processes. Radionuclide lung scanning also provides an estimate of target areas, volume occupying but nonfunctioning lung. Cohort studies utilizing these imaging techniques have demonstrated associations between preoperative characteristics and postoperative outcome. The imaging studies, especially the chest radiograph, have also played an important role in postoperative management. Many other imaging options are available, such as HRCT scan, quantitative CT scan, and single photon emission CT scan. Other techniques, such as MR imaging, may play a future role as well.

New principles for the treatment of diffuse pulmonary emphysema

Emphysema is due to destruction of lung tissue but the main cause of the dyspnoea is a diminished elasticity of the lungs. Medical therapy, such as bronchodilation, corticosteroids, and treatment of intercurrent infections, can give temporary relief. Long-term oxygen treatment can improve and prolong life in patients with severe epmphysema. Lung transplantation is a final option in selected patients. Rehabilitation including exercise training will cause increase in maximal exercise tolerance and decrease of dyspnoea, and thereby an improvement of quality of life. In recent years surgical reduction of the lung volume has been reintroduced and in selected cases given dramatic results. The goal is to reduce the volume in both lungs with about 30%. Depending on the distribution of the emphysema, pieces of the upper or lower lobes will be removed. Sternotomy or bilateral thoracoscopy, using staplers, are the most common methods. Short-term results are good, with an improvement of FEV1 of 22-96%, improved arterial oxygen pressure, and a radical improvement of life quality. The impact on the daily life of the patient can be dramatic. The long-term results are still not well known, and many questions remain before volume reduction surgery can be regarded as an established form of treatment for emphysema, and randomized studies are badly needed.

Surgical options for patients with advanced emphysema

Since the early 1900s, a variety of operations have been suggested for emphysema but, with the exception of giant bullectomy, an option in only a small fraction of patients, none has proven effective. Data collected by a number of academic medical centers indicate that LVRS may ameliorate symptoms and improve pulmonary physiology, function, and quality of life in appropriately selected patients with emphysema. Accordingly, LVRS may provide an opportunity to intervene in a rapid, effective, and, possibly, cost-effective manner in a debilitating, chronic disease. That is an extraordinarily attractive proposition for both patients and physicians alike. But a number of questions remain: (1) What is the effect of LVRS compared with maximal medical therapy? (2) What is the duration of any beneficial effect of LVRS? (3) What is the best operative approach? (4) What patient characteristics predict good and bad outcomes? (5) What is the role of pre- and, possibly, postoperative pulmonary rehabilitation? (6) Does LVRS adversely affect the rate of loss of lung function over time, as some have suggested? (7) What is the cost of LVRS compared with standard medical therapy? (8) Can the procedure be performed safely in nontransplant centers? (9) What is the effect on disease-specific quality of life? (10) Does it affect mortality? A prospective, randomized controlled trial involving 18 selected centers will begin in the fall of 1997 under the sponsorship of the Health Care Financing Corporation (the administrators of Medicare) and the National Institutes of Health. We strongly support the creative, collaborative approach that has been taken by those two government agencies to stimulate this study. The need for controlled trials of new therapies cannot be overstated; only with such trials can the questions enumerated above be answered with certainty.

Evaluation and preoperative management of lung volume reduction surgery candidates

The efficacy of lung volume reduction surgery has been demonstrated by improvements in functional status, dyspnea, pulmonary function, alveolar gas exchange, and exercise tolerance. However, surgery has a significant morbidity, mortality, and cost. Surgical outcome is dependent on the clinical, anatomical, and physiological features of the patients and their emphysema. Therefore, the patient evaluation process and the preoperative optimization of medical therapy are crucial for success. Through understanding mechanisms for improvement have added insight to the selection process, patient selection needs further clarification.

Lung volume reduction surgery: an overview

Lung volume reduction surgery, originally used in the 1950s, has reemerged as a technique that may help some individuals with end-stage emphysema breathe more easily. The goal of the surgery is to enhance elastic recoil of the lung and to restore diaphragmatic function. The surgery is still in the experimental stages, but early outcome data are encouraging. The purpose of this study was to discuss the pathology of emphysema and the rationale for lung volume reduction. The patient selection criteria for the operation are discussed, and information is provided regarding the preoperative and postoperative management and rehabilitation of these patients by physicians, nurses, respiratory therapists, and physical therapists.

Bilateral volume reduction surgery for diffuse pulmonary emphysema by video-assisted thoracoscopy

We prospectively studied the surgical aspects, functional results, and complications of video-assisted bilateral thoracoscopic volume reduction surgery in patients with severe diffuse pulmonary emphysema.

METHODS

Fifteen men and five women with a mean age of 64 years (range 42 to 78 years) whose daily activity was substantially impaired by severe airflow obstruction and hyperinflation underwent thoracoscopic volume reduction surgery. The prospective preoperative assessment and postoperative assessment at 3 months included (1) pulmonary function studies, (2) grading of dyspnea, and (3) exercise performance; pulmonary function tests were also performed immediately before discharge from the hospital.

RESULTS

There was no perioperative mortality. All patients left the hospital after a median stay of 15 days (6 to 27 days). Only seven patients had a prolonged chest tube drainage time (>7 days). At 3 months the mean (+/- standard deviation) forced expiratory volume in 1 second had improved by 42% (+/-3.8%), from 0.80 L (+/-0.23) to 1.09 L (+/-0.28) (p < 0.001); residual volume had decreased from 5.8 L (+/-1.5) to 4.4 L (+/-1.0) (p < 0.001). Shortly before discharge the forced expiratory volume in 1 second was already 1.10 L (+/-0.26). The median 12-minute walking distance increased from 495 m (35 to 790 m) to 688 m (175 to 1035 m) (p < 0.001) and the mean maximal oxygen consumption from 10 ml/kg per minute (+/-2.5) to 13 ml/kg per minute (+/-2.3) (p < 0.0005). The patients reported a substantial relief of dyspnea with a mean decrease in the Medical Research Council score from 3.4 to 1.8.

Thoracoscopic laser bullectomy: a prospective study with three-month results

One hundred forty-one patients were prospectively enrolled in a study of contact-tip laser bullectomy at four institutions. Ninety-one have had both preoperative and postoperative testing at 3 months. Nonsmoking patients with disabling dyspnea at less than 50 yards and with a forced expiratory volume in 1 second of 35% or less were enrolled. Testing included formal pulmonary function tests, arterial blood gasses, computed tomographic scans, ventilation/perfusion scans, echocardiograms, electrocardiograms, 6-minute walk testing, transdiaphragmatic pressures, and quality of life and dyspnea index questionnaires. A modest 16% improvement was noted in forced expiratory volume in 1 second (0.69 to 0.80 L), and there was a 29% improvement in 6-minute walk distances (655.2 to 846.3 feet). Oxygen use was completely discontinued in 16%. Risk factors for mortality included age, 6-minute walk distances, low diffusing capacity for carbon monoxide, high carbon dioxide tension, and high base excess. Minor improvement was judged from the dyspnea index and the Medical Outcome Study Short Form-36. Preoperative predictors of good outcome included heterogeneous disease, lack of carbon dioxide retention, and no emaciation (weight < 40 kg). Comparison of our results with those in the literature suggests that the improvement seen with the contact neodymium:yttrium-aluminum-garnet laser is not as good as that provided by the stapled techniques for volume reduction.

Lung volume reduction surgery for emphysema

There has been dramatic resurgence of interest in surgical treatment of emphysema, particularly "lung volume reduction" procedures. Recent studies have demonstrated improvements in pulmonary function, lung mechanics, exercise tolerance, and quality of life in selected patients following volume reduction procedures. However, considerable uncertainty remains regarding overall benefit, optimal patient selection, operative techniques, and duration of response. This summarizes current approaches to lung volume reduction surgery, available clinical outcome information, selection criteria, and physiologic mechanisms of response, and discusses the potential role for surgical volume reduction in treatment of emphysema. Recent data appear to support the efficacy of bilateral staple lung volume reduction surgery in patients with severe symptomatic heterogeneously distributed emphysema. Further studies will be needed to determine relative value of different operative techniques and benefit in patients with other clinical presentations.

Improvement in pulmonary function and elastic recoil after lung-reduction surgery for diffuse emphysema

BACKGROUND

Pulmonary function may improve after surgical resection of the most severely affected lung tissue (lung-reduction surgery) in patients with diffuse emphysema. The basic mechanisms responsible for the improvement, however, are not known.

METHODS

We studied 20 patients with diffuse emphysema before and at least three months after either a unilateral or a bilateral lung-reduction procedure. Clinical benefit was assessed by measurement of the six-minute walking distance and the transitional-dyspnea index, which is a subjective rating of the change from base line in functional impairment and the threshold for effort- and task- dependent dyspnea. Pressure-volume relations in the lungs were measured with static expiratory esophageal-balloon techniques, and right ventricular systolic function was assessed by echocardiography.

RESULTS

The patients had significant improvement in the transitional-dyspnea index after surgery (P<0.001). The mean (+/-SD) coefficient of retraction, an indicator of elastic recoil of the lung, improved (from 1.3+/-0.6 cm of water per liter before surgery to 1.8+/-0.8 after, P<0.001). Sixteen patients with increased elastic recoil had a greater increase in the distance walked in six minutes than the other four patients, in whom recoil did not increase (P=0.02). The improved lung recoil led to disproportionate decreases in residual volume as compared with total lung capacity (16 percent vs. 6 percent), but the decreases in both values were significant (P<0.001). Forced expiratory volume in one second increased (from 0.87+/-0.36 to 1.11+/-0.45 liters, P<0.001). End-expiratory esophageal pressure also decreased (P=0.002). These improvements in lung mechanics led to a decrease in arterial partial pressure of carbon dioxide form 42+/-6 to 38+/-5 mm Hg (P=0.006). Furthermore, the fractional change in right ventricular area, an indicator of systolic function, increased from 0.33+/-0.11 to 0.38+/-0.010 (P=0.02).

CONCLUSIONS

Lung-reduction surgery can produce increases in the elastic recoil of the lung in patients with diffuse emphysema, leading to short-term improvement in dyspnea and exercise tolerance.

Bilateral pneumectomy (volume reduction) for chronic obstructive pulmonary disease

We undertook surgical bilateral lung volume reduction in 20 patients with severe chronic obstructive pulmonary disease to relieve thoracic distention and improve respiratory mechanics. The operation, done through median sternotomy, involves excision of 20% to 30% of the volume of each lung. The most affected portions are excised with the use of a linear stapling device fitted with strips of bovine pericardium attached to both the anvil and the cartridge to buttress the staple lines and eliminate air leakage through the staple holes. Preoperative and postoperative assessment of results has included grading of dyspnea and quality of life, exercise performance, and objective measurements of lung function by spirometry and plethysmography. There has been no early or late mortality and no requirement for immediate postoperative ventilatory assistance. Follow-up ranges from 1 to 15 months (mean 6.4 months). The mean forced expiratory volume in 1 second has improved by 82% and the reduction in total lung capacity, residual volume, and trapped gas has been highly significant. These changes have been associated with marked relief of dyspnea and improvement in exercise tolerance and quality of life. Although the follow-up period is short, these preliminary results suggest that bilateral surgical volume reduction may be of significant value for selected patients with severe chronic obstructive pulmonary disease.

Surgical treatment of bullous emphysema: experience with the Brompton technique

The technique first described by Monaldi has been modified for the treatment of discrete emphysematous bullae. Fifty-eight patients (median age, 56 years) underwent this procedure between 1983 and 1992. The operative mortality was 6.9% (4 patients). Fifty-two patients (89.6%) noted symptomatic improvement, as measured using the modified Medical Research Council of Great Britain dyspnea scale, from a mean value of 3.7 preoperatively to 2.1 postoperatively. Two patients remained unchanged symptomatically. In all patients, amelioration of symptoms was accompanied by an objective improvement in lung function. A mean increase of 28% was noted in the forced expiratory volume in 1 second (p < 0.05), and a 12.3% improvement in the total lung capacity was observed (p < 0.002). The residual lung volume-total lung capacity ratio declined from a mean of 70% to 57% after operation. A forced expiratory volume in 1 second of less than 500 mL (p < 0.05) and carbon dioxide tension of greater than 6.5 kPa (p < 0.05) were significant predictors of poor prognosis. The median follow-up period has been 1.9 years (range, 0.5 to 9 years). Two patients have returned for further drainage of new bullae on the operated side, and this was carried out percutaneously in both. We conclude that this technique offers a simple, safe, and effective method for the treatment of discrete bullous disease in patients with emphysema.

Cystic and bullous lung disease

One of the most difficult problems facing clinicians is the evaluation and management of patients with dyspnea whose chest roentgenogram shows single or multiple large cystic spaces. This is made more difficult when underlying lung disease is present. The dilemma focuses on whether the obliteration or removal of the cystic areas will benefit or cause further deterioration of the patient's condition. The pathophysiology of the problem is not completely understood, but accumulated clinical experience has shown that surgical therapy can be beneficial but requires proper patient selection.

Intracavity drainage for bullous, emphysematous lung disease: experience with the Brompton technique

Twenty two operations have been performed on 20 patients for the relief of symptoms due to bullous lung disease. Open intubation drainage of the bullae was used in all patients, the technique initially devised by Monaldi for the treatment of intrapulmonary tuberculous abscesses having been modified. Three patients died after surgery. Mortality was associated with low preoperative FEV1 (median 350 ml) and higher preoperative arterial carbon dioxide tension (PaCO2) (median 7.8 kPa). Symptomatic improvement was reported by 16 of the remaining 17 patients and was maintained over a median follow up period of 1.6 years. This was accompanied by objective improvement in lung function with a 22% median improvement in FEV1, an 11% median reduction in total lung capacity, and a 26% median reduction in residual volume. In one patient symptoms were unchanged after surgery. The technique described provides a simple method for decompressing bullae by means of a minimally invasive surgical procedure. It also allows for the treatment of further bullae at a later date by closed intubation under local anaesthetic. It has proved a suitable approach for all but those with the poorest lung function and is now our treatment of choice.

Effect of removal of bullae on airway conductance and conductance volume ratios

Airway conductance is known to increase with an increase in the lung volume at which it is measured, owing to a change in transpulmonary pressure and lung tissue tension. We investigated the effect of surgical resection of lung tissue on functional residual capacity and airway conductance in patients with localized lung disease (i.e., carcinoma or tuberculosis) and in patients with lung cysts or bullous emphysema. In four out of five of the patients who had resection of one or more lobes of the lung to remove localized disease there was a reduction both in the airway conductance and in the functional residual capacity with relatively little change in the conductance volume ratio. By contrast, in all patients who underwent bullectomy, there was a decrease in functional residual capacity but an increase in airway conductance, and an increase in the conductance/volume ratio. This change was sustained in patients who had had localized cysts removed. However, the measurements gradually reverted toward preoperative values in those patients who had generalized emphysema. The increase in airway conductance after resection of blebs and bullae presumably was due to improved lung elastic pressure causing the airways to increase in diameter and conductance. In addition, some patients may have experienced relief of compression of neighboring airways.