Lung reduction surgery in chronic obstructive lung disease

Novel surgical system for reducing lung tissue and preventing air leaks

PURPOSE

This study assessed the feasibility of using the VALR surgical system (Spiration Inc, Redmond, WA), limited by federal law to investigational use, for capturing and reducing a selected portion of affected lobes in patients undergoing lobectomy.

DESCRIPTION

The tested system consists of a hand-held vacuum-regulated introducer loaded with a flexible, silicone sleeve. Targeted tissue is drawn into the introducer and the silicone sleeve is deployed and sutured in place. The end of the proximal sleeve includes a compression band for applying uniform radial pressure, suture ports, and silicone lugs lining the inner lumen for reinforcing sleeve position.

EVALUATION

The system was effective in capturing 25% to 30% tissue of each lobe tested. Mean intraoperative test time was 8.5 minutes. The compression sleeve did not slip or dislodge after suturing, and no tissue damage or leaks were observed.

CONCLUSIONS

It was feasible using vacuum to draw and isolate a portion of pulmonary tissue within a silicone sleeve. The system was intuitive to apply, easy to use, and produced effective reduction and sealing of tissue.

Selection of patients for lung volume reduction surgery using a power law analysis of the computed tomographic scan

BACKGROUND

A study was undertaken to test the hypothesis that patients respond better to lung volume reduction surgery (LVRS) if their emphysema is confluent and predominantly located in the upper lobes.

METHODS

A density mask analysis was used to identify voxels inflated beyond 10.2 ml gas/g tissue (-910 HU) on preoperative and postoperative CT scans from patients receiving LVRS. These hyperinflated regions were considered to represent emphysematous lesions. A power law analysis was used to determine the relationship between the number (K) and size (A) of the emphysematous lesions in the whole lung and two anatomical regions using the power law equation Y=KA(-D).

RESULTS

The analysis showed a positive correlation between the change in the power law exponent (D) and the change in exercise (Watts) after surgery (r=0.47, p=0.03). There was also a negative correlation between the power law exponent D in the upper region of the lung preoperatively and the change in exercise following surgery (r=-0.60, p<0.05).

CONCLUSIONS

These results confirm that patients with large upper lobe lesions respond better to LVRS than patients with small uniformly distributed disease. Power law analysis of lung CT scans provides a quantitative method for determining the extent and location of emphysema within the lungs of patients with COPD.

Improvement in spirometry following lung volume reduction surgery: application of a physiologic model

According to a previously published theoretical model of emphysema, the ratio of RV to TLC (RV/TLC) reflects the size mismatch between the hyperinflated lungs in the disease and the surrounding chest. The model suggests that RV/TLC is an important predictor of improvement in FVC and that increased FVC is an important determinant of increased FEV(1) after lung volume reduction surgery (LVRS). We tested these predictions in 13 patients undergoing LVRS, in whom we made detailed measurements of lung mechanics. Using stepwise regression, we found that RV/TLC was the only preoperative independent predictor of the increase in FVC. Seventy percent of the increase in FEV(1) was attributable to increased FVC, with the remainder due to increased FEV(1)/FVC. In a separate group of 78 LVRS patients evaluated with standard preoperative pulmonary function tests, RV/TLC again was found to correlate with the increase in FVC, and changes in FEV(1) were also due largely to changes in FVC. However, RV/TLC was not predictive of the increase in FEV(1) among the group of 78 patients, because FEV(1)/FVC in patients with a low preoperative RV/TLC often increased despite little change in FVC. These findings support the proposed mechanism for increased FVC following LVRS. They also illustrate the limitations of the model, and suggest further hypotheses for selecting patients who may benefit from surgery.

Core to rind distribution of severe emphysema predicts outcome of lung volume reduction surgery

Computed tomography (CT) has shown that emphysema is more extensive in the inner (core) region than in the outer (rind) region of the lung. It has been suggested that the concentration of emphysematous lesions in the outer rind leads to a better outcome following lung volume reduction surgery (LVRS) because these regions tend to be more surgically accessible. The present study used a recently described, computer-based CT scan analysis to quantify severe emphysema (lung inflation > 10.2 ml gas/g tissue), mild/moderate emphysema (lung inflation = 10.2 to 6.0 ml gas/g tissue), and normal lung tissue (lung inflation < 6.0 ml gas/g tissue) present in the core and rind of the lung in 21 LVRS patients. The results show that the quantification of severe emphysema independently predicts change in maximal exercise response and FEV(1). We conclude that a greater extent of severe emphysema in the rind of the upper lung predicts greater benefit from LVRS because it identifies the lesions most accessible to removal by LVRS.

Preoperative severity of emphysema predictive of improvement after lung volume reduction surgery: use of CT morphometry

STUDY OBJECTIVE

To determine how the volume and severity of emphysema measured by CT morphometry (CTM) before and after lung volume reduction surgery (LVRS) relates to the functional status of patients after LVRS.

DESIGN

A histologically validated CT algorithm was used to quantify the volume and severity of emphysema in 35 patients before and after LVRS: total lung volume (TLV), normal lung volume (< 6.0 mL gas per gram of tissue), volume of mild/moderate emphysema (ME; 6.0 to 10.2 mL gas per gram of tissue), volume of severe emphysema (> 10.2 mL gas per gram of tissue), surface area/volume (SA/V; meters squared per milliliter), and surface area (SA; meters squared). Outcome parameters included maximal cardiopulmonary exercise (CPX) performance in 21 patients and routine pulmonary function in all patients. We hypothesized that baseline CTM parameters predict response to LVRS and that the change in these parameters may offer insight into mechanisms of improvement.

PATIENTS AND INTERVENTION

Thirty-five patients with severe emphysema who had successful LVRS.

RESULTS

The significant decrease in TLV following LVRS was entirely accounted for by a decrease in severe emphysema. The SA/V and the SA both increased significantly following LVRS. The change in maximal CPX in watts following surgery correlated significantly with baseline values of severe emphysema (r = 0.60), which was collinear with TLV, and SA/V. The change in diffusing capacity of the lung for carbon monoxide revealed a significant positive linear relationship with preoperative severe emphysema (r = 0.37) and a negative relationship with ME (r = -0.37). Change in watts revealed a strong relationship with changes in severe emphysema (r = -0.75) and weaker but significant relationships with change in TLV, ME, SA/V, and SA. Other measures of pulmonary function revealed significant albeit less dominant relationships with baseline CTM and change in these indexes.

CONCLUSION

Using CTM, we have identified a close relationship between baseline severe emphysema, or change in severe emphysema, and the improvement in CPX after LVRS. These observations support a potential role of CTM in future clinical trials for predicting responders to LVRS and identifying mechanisms of improvement.

Lung volume reduction surgery (LVRS) for emphysema: initial experience at the University Hospital Gasthuisberg. Leuven LVRS Group

Emphysema is a disabling disease, for which there is no curative therapy available today. Lung transplantation offers a valuable option for a very selected number of patients, however, due to the enormous organ shortage, only few patients can be offered such a therapy. Recently there has been important resurgence of interest in lung volume reduction surgery and as a consequence, we have embarked in such a program since may 1997. We have now performed unilateral lung volume reduction surgery in 29 emphysema patients (25 on the right and 4 on the left side). Twenty-four patients were already discharged home. There has been no perioperative mortality. The mean hospital stay was 19.8 +/- 11.4 days (range, 8-47 d). Twenty patients of whom we already have follow-up data during 6 months (m) form the further basis of this report. Six weeks after the procedure the FEV1 increased from 0.82 +/- 0.28 L (28 +/- 8%) to 1.05 +/- 0.39 L, a mean increase of 28%. There was a further increase of the FEV1 to a maximum of 1.06 +/- 0.42 L at 6 m, a mean maximum increase of 29% (p = 0.0046, ANOVA). Similarly, the FVC increased from 2.80 +/- 1.10 L to 3.15 +/- 1.00 L, a mean increase of 12.5%. A further increase was also obtained at 6 m and was 19.6% (3.35 +/- 1.05 L, p = 0.014, ANOVA). The maximum decrease in RV was obtained at 3 m (from 5.91 +/- 1.37 L to 4.37 +/- 0.85 L (p = 0.0001, ANOVA), a mean decrease of 26%. The maximum TLC decrease was demonstrated at 3 m (from 8.71 +/- 1.71 L to 7.60 +/- 1.56 L (p = 0.002, ANOVA), a mean decrease of 12.8%. Afterwards there was again a gradual raise of the TLC. The six minute walking distance increased from 231 +/- 31 m to 272 +/- 34 m (p = NS) after pulmonary rehabilitation and to 416 +/- 77 m at 3 m and 415 +/- 18 m at 6 m (p = 0.0002, ANOVA) after the operation. The quality of life (measured with a standardized questionnaire, the Nottingham Health Profile) improved significantly in several domains (e.g. mobility, pain, energy, emotions and social) at 3 m postoperatively. There was one late death (at 6 m) due to an unknown cause. The actuarial survival rate was therefore 100% at 3 m and 95% at 12 m. In conclusion, unilateral thoracoscopic lung volume reduction surgery is a new and safe treatment modality for patients suffering from severe end-stage emphysema. The objective and subjective improvement is marked and the mortality is very low. Rigid selection criteria are, however, necessary to be able to guarantee an optimal result.

Current status of lung volume reduction

Lung volume reduction surgery, where 20-30% of lung is resected in patients with end-stage emphysema, has been shown in a number of published series to improve expiratory lung volumes, exercise capacity, and subjective well being. This procedure, originally described in the early 1950s, has caught the imagination of the public and medical fraternity. This operation may find utility as an alternative to lung transplantation. Only when the results of a number of randomized clinical trials are available, however, will an assessment of the true value of this procedure be known.

A quantification of the lung surface area in emphysema using computed tomography

Quantitative analysis of computed tomography (CT) has been combined with a stereologically based histologic analysis of lung structure to assess regional lung inflation and the structural features of the lung parenchyma. In this study, CT measurements of lung inflation were compared with histologic estimates of surface area in order to develop prediction equations that allow lung surface to volume ratio and surface area to be predicted from an analysis of the CT scan. The results show that mild emphysema is associated with an increase in lung volume and a reduction in surface to volume ratio, whereas surface area and tissue weight were only decreased in severe disease. The CT predicted surface to volume ratio correlated with histology, and both predicted and measured surface areas correlated with the diffusing capacity. We conclude that this CT analysis can be used to monitor the progression of emphysematous lung destruction in individual patients, and to assess the impact of both surgical and medical treatments for emphysema.

Bilateral apical vs nonapical stapling resection during lung volume reduction surgery

STUDY OBJECTIVES

To determine whether biapical stapling resection alone or resection of diseased, nonapical areas of emphysematous lung provides comparable physiologic outcomes or alters morbidity and mortality after lung volume reduction surgery (LVRS).

DESIGN

Consecutive case-series analysis.

SETTING

Urban university hospital.

PATIENTS

Forty-seven patients ([mean +/- SD] aged 58+/-8 years; 18 men) with severe emphysema (FEV1, 0.7+/-0.2 L; total lung capacity [TLC], 139+/-23% predicted).

INTERVENTIONS

Thirty-two patients underwent biapical LVRS, 27 by median sternotomy (MS) and 5 by video-assisted thoracoscopic surgery (VATS), and 15 underwent nonapical resection, 9 by MS and 6 by VATS. Patients were assessed for postoperative complications (respiratory tract infections, air leak duration, and death), length of stay, and physiologic parameters, which included a 6-min walk distance, spirometry, lung volume, gas exchange, diaphragm strength, and quality-of-life measures.

MEASUREMENTS AND RESULTS

Patients were studied at baseline and at 3 months postoperatively. At the preoperative baseline, both groups had similar ages (57 vs 60 years; p = 0.2), 6-min walk distance (294 vs 263 m; p = 0.3), FEV1 (28% vs 29% predicted; p = 0.6), degree of hyperinflation (TLC, 138% vs 141% predicted; p = 0.8), gas exchange (PaO2/fraction of inspired oxygen, 344 vs 313, p = 0.1; PaCO2 46 vs 48 mm Hg, p = 0.4), and diaphragm strength (maximal transdiaphragmatic pressure sniff, 54 vs 46 cm H2O, p = 0.4). Resected tissue weight was similar in both groups (94 vs 93 g, p = 0.9). There were no differences in the mean percentage of change from baseline for these physiologic parameters or for quality-of-life measures between the two groups. The 6-min walk distances increased by 20% and 33%, FEV1 increased by 37% and 38%, the degrees of hyperinflation (residual volume/TLC) decreased by 16% and 15%, and the quality-of-life scores improved by 51% and 41%, respectively, in the groups that underwent biapical and nonapical resections at 3 months post-LVRS. The length of stay in the hospital for LVRS (18 vs 23 days; p = 0.4) and the duration of air leak (10 vs 15 days; p = 0.4) were also similar. Complications between the two groups (biapical vs nonapical) were similar (respiratory tract infection, 47% vs 60%, p = 0.2; reintubation, 34% vs 33%, p = 0.2; reoperation, 9% vs 20%, p = 0.4; and death, 9% vs 7%, p = 0.2).

CONCLUSIONS

LVRS, by biapical or nonapical resection, produces similar improvements in lung function, exercise, diaphragm strength, and quality of life, with comparable morbidity and mortality.

Lung volume reduction surgery: answering the crucial questions

Emphysema and other forms of COPD are not only common, but also have a poor prognosis. Mortality with severe COPD may be as high as 60% at 5 years and is associated with a significant degree of disability and cost to the health-care system. Building on Dr. Otto Brantigan's experience in the 1950s, when multiple-wedge resections of emphysematous lung were performed to decrease lung volume, thereby improving airflow and reducing hyperinflation, recent investigators, utilizing improved surgical and anesthetic technique, have redeveloped a surgical approach to the treatment of emphysema. The operations used to treat emphysema include excision of large bullae (bullectomy) and resection of diffusely emphysematous lung and are variously known as lung volume reduction surgery (LVRS), pneumectomy, and reduction pneumoplasty. These operations aim for a 20 to 30% reduction in lung volume and may be performed by stapler or laser resection, or both. The mechanisms of benefit have been attributed to enhanced elastic recoil, correction of ventilation perfusion mismatch, improved efficiency of respiratory musculature, and improved right ventricular filling. Questions that remain to be answered include duration of benefits, safety, and cost of LVRS. The National Heart, Lung, and Blood Institute and the Health Care Financing Administration have responded to the demand for more access to and information about LVRS by organizing both a national registry and controlled clinical trial of these procedures over a 7-year period. This multicenter trial intends to enroll patients with end-stage emphysema to compare methods of bilateral LVRS to maximal medical therapy.

Lung volume reduction surgery for emphysema

OBJECTIVE

To report the results of lung volume reduction surgery (LVRS) for severe emphysema in Australia.

SETTING

A tertiary teaching hospital.

DESIGN

A prospective study of a consecutive case series.

PARTICIPANTS

20 patients (mean age, 56 years) with severe emphysema--mean forced expiratory volume in one second (FEV1), 0.72 L (28% of predicted) and severe gas trapping (mean residual volume, 286% of predicted).

INTERVENTION

Bilateral apical LVRS was performed via a median sternotomy with a linear stapler; bovine pericardial strips were used to reinforce the staple line.

RESULTS

There was a 95% survival, and a mean (range) inpatient stay of 17 (8-45) days. No complications occurred in nine patients; a further six patients had only minor complications. Five patients had major complications (sputum retention requiring reintubation, persistent air leak requiring reoperation, duodenal perforation, and epidural haemorrhage); one patient died from multiorgan failure at 28 days. Intercostal drainage was left in situ for a mean of eight days. The results of FEV1, Medical Research Council (MRC) Dyspnoea Score and six-minute walk test improved in more than 90% of patients. FEV1 improved an average of 0.35 L (54% over baseline) (P < 0.001). Mean MRC Dyspnoea Score decreased from 3.4 to 2.1 (P < 0.001). Mean distance for the six-minute walk test increased from 306 to 431 metres (P < 0.001).

CONCLUSION

Our experience confirms that LVRS produces worthwhile early outcomes for a subgroup of patients with severe emphysema. The clinical, economic and ethical questions raised by this new therapy will need to be assessed.

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.

Lung volume reduction surgery at a community hospital: program development and outcomes

STUDY OBJECTIVES

Description of the development and results of a program in lung volume reduction surgery (LVRS) at a community hospital.

DESIGN

Prospective data collection.

SETTING

A 320-bed community hospital.

PATIENTS

Fifty-five patients consecutively discharged from the hospital following LVRS. The mean preoperative FEV1 averaged 28% (+/-8%) of predicted values, while the preoperative PaCO2 averaged 49 mm Hg (+/-11.5 mm Hg). Forty-eight patients completed a preoperative conditioning regimen and underwent the procedure on an elective basis. Seven patients underwent the procedure during a hospital admission for a COPD exacerbation. Eight patients required mechanical ventilation preoperatively, including three who had required long-term mechanical ventilatory support.

RESULTS

Three patients (5%) died in the hospital following surgery. One patient developed chronic ventilator dependence. All three of the patients who required long-term mechanical ventilation preoperatively were weaned from the ventilator and returned home. Follow-up pulmonary function testing is available for 42 patients 3 months after surgery, and for 20 patients 6 months after the operation. At 3 months, the mean FEV1 improved 0.19 L (p=0.0002), the mean improvement for FVC was 0.37 L (p=0.0001), and the mean drop in residual volume was 0.97 L (p=0.0001). Similar changes are seen at 6 months. Highly significant improvements were also seen in quality of life measurements and exercise performance. The benefits of surgical treatment of emphysema seemed similar in both elective and urgent groups.

CONCLUSIONS

LVRS can be done safely and effectively at a community hospital, with significant improvement in pulmonary function and quality of life.

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.