Weight gain after lung volume reduction surgery is not correlated with improvement in pulmonary mechanics

Reduction in resting energy expenditure following lung volume reduction surgery in subjects with chronic obstructive pulmonary disease

Study objectives: Some subjects with COPD have an elevated resting energy expenditure (REE)which may be related to an increased work of breathing at rest. The purpose of this study was to examine the effect of lung volume reduction surgery (LVRS) on REE and body weight. Design: Ten subjects with COPD were recruited (mean age + SD = 61.4 + 6.1 years). At baseline (which was following preoperative pulmonary rehabilitation) and four months following LVRS (combined with postoperative pulmonary rehabilitation), each subject had tests of lung function, REE via indirect calorimetry using a canopy system, six minute walk distance (6MWD) and quality of life (QoL) using the St George's Hospital Respiratory Questionnaire (SGRQ). Measurements: The FEV, (% predicted) increased from 27.7 + 5.8% (mean + SD) at baseline to 33.9 + 7.8% following LVRS (P < 0.05). REE (% predicted) was 110 + 9.8% at baseline and decreased to 106 + 6.7% following LVRS (P = 0.04). Body mass index (BMI) following LVRS was unchanged (P = 0.67). No correlation between the change in BMI and change in REE was shown (r2 = 0.3, P = 0.1). Therewas a significant improvement in QoL following LVRS (P < 0.001). 6MWD also significantly increased from 354 + 83 m to 412 + 82 m following LVRS (P = 0.001). Conclusion: Whilst there was an increase in lung function and a reduction in REE following LVRS, there was no corresponding change to body weight. The improvement in REE following LVRS may be related to an improvement in work of breathing.

Effects of lung volume reduction surgery for emphysema on glycolipidic hormones

BACKGROUND

Pulmonary emphysema is associated with cachexia and disregulation of the hormones regulating the glycolipid metabolism, insulin resistance, and altered substrate utilization. This study aimed at identifying the effects of lung volume reduction surgery (LVRS) on glycolipidic hormones compared to respiratory rehabilitation (RR).

METHODS

Thirty-three patients with moderate-to-severe emphysema who were undergoing video-assisted thoracoscopic LVRS were compared to 31 similar patients who refused the operation and followed a standardized RR program. All patients were evaluated before and 12 months after treatment for respiratory function, body composition, glycolipidic hormones, metabolic parameters, and insulin resistance, which was calculated using the homeostatic model assessment index for insulin resistance (HOMA-IR). These groups were compared to a matched healthy control population.

RESULTS

Only after LVRS significant improvements were obtained in respiratory function (FEV1, +25.2%; p<0.0001; residual volume, -19.5%; p<0.0001), metabolic parameters (total cholesterol, +13.1%; p<0.01; high-density lipoprotein cholesterol, +11.2%; p<0.01; triglycerides, +18.4; p<0.001; nonesterified fatty acid, -19.7%; p<0.001), and body composition (fat-free mass [FFM], +6.5%; p<0.01; fat mass [FM], +11.9%; p<0.01). The leptin/FM ratio (-6.1%; p<0.01) and resistin/FM ratio (-5.6%; p<0.01) decreased, whereas the adiponectin/FM ratio (+6.9%; p<0.01) and ghrelin (+9.2%; p<0.01) increased, together with reductions in glycemia (-8.8%; p<0.01), insulin level (-20.4%; p<0.001), and HOMA-IR (-27.2%; p<0.0001). The decrement in residual volume was correlated with increment of FFM (rho=-0.49; p<0.02), FM (rho=-0.55; p<0.009), and ghrelin (rho=-0.52; p<0.01), and also with decreases in leptin corrected for FM (rho=0.50; p<0.02) and, marginally, HOMA-IR (rho=0.35; p=0.07).

CONCLUSIONS

After LVRS, glycolipidic hormone levels and nutritional status significantly improved, along with insulin resistance reduction and more physiologic utilization of substrates. Correlations between residual volume and body composition as well as glycolipidic hormone levels suggest that postoperative recovery in respiratory dynamics may induce favorable clinical changes when compared to RR.

Bone Mineral Density Improvement After Lung Volume Reduction Surgery for Severe Emphysema

BACKGROUND

In patients with severe emphysema, bone mineral density (BMD) is reduced and the risk of osteoporosis is increased.

STUDY OBJECTIVES

To identify the impact of lung volume reduction surgery on BMD.

DESIGN

Prospective cohort study.

SETTING

University hospital.

PATIENTS AND INTERVENTIONS

Forty emphysematous patients, all receiving oral steroid therapy, underwent bilateral lung volume reduction surgery. Thirty similar patients, who refused the operation, followed a standard respiratory rehabilitation program.

MEASUREMENTS

All subjects were evaluated pretreatment and 12 months posttreatment for respiratory function, nutritional status, and bone-related biochemical parameters. BMD was assessed by dual-energy radiograph absorptiometry.

RESULTS

After surgery, we observed significant improvements in respiratory function (FEV1, + 18.8% [p < 0.01]; residual volume [RV], -29.6% [p < 0.001]; diffusing capacity of the lung for carbon monoxide [Dlco], + 21.6% [p < 0.01]) nutritional parameters (fat-free mass, + 6.0% [p < 0.01]), levels of bone-related hormones (free-testosterone, + 20.5% [p < 0.01]; parathormone, -11.2% [p < 0.01]), bone turnover markers (osteocalcin, -12.7% [p < 0.05]; bone-alkaline-phosphatase, -14.0% [p < 0.05]; beta-crosslaps, -33.6% [p < 0.001]), BMD (lumbar, + 8.8% [p < 0.01]; femoral, + 5.5% [p < 0.01]), and T-score (lumbar, + 21.0% [p < 0.01]; femoral, + 12.4% [p < 0.01]) with reduction in osteoporosis rate (50 to 25%). Nineteen patients who had undergone surgery were able to discontinue treatment with oral steroids. These subjects showed a more significant improvement in BMD (lumbar, + 9.6%; femoral, + 6.8%; p < 0.001) and T-score (lumbar, + 27.3%; femoral, + 14.3%; p < 0.001). The remaining 21 patients who had undergone surgery experienced significant improvement compared to respiratory rehabilitation subjects despite continued therapy with oral steroids (BMD: lumbar, + 4.5% vs -0.7%, respectively [p < 0.01]; femoral, + 2.7% vs -1.1%, respectively [p < 0.05]; T-score: lumbar, + 14 vs -2.1, respectively [p < 0.01]; femoral, + 7.4 vs -2.7, respectively [p < 0.01]). The increase in lumbar BMD was correlated with the surgical reduction of RV (p = 0.02) and with the increase in Dlco (p = 0.01) and fat-free mass (p = 0.01).

CONCLUSIONS

Lung volume reduction surgery significantly improves BMD compared to respiratory rehabilitation therapy, even in patients requiring oral steroids. The increase in BMD correlates with RV, Dlco, and fat-free mass, suggesting that the restoration of respiratory dynamics, gas exchange, and nutritional status induces improvement in bone metabolism and mineral content.

The increase in body mass index observed after lung volume reduction may act as surrogate marker of improved health status

OBJECTIVE

To assess the effects of lung volume reduction surgery (LVRS) on body mass index (BMI).

METHODS

Prospective data was collected on a series of 63 patients undergoing LVRS (bilateral in 22 patients, unilateral in 41 patients). Median age was 58 (41-70) years. The peri-operative effects of LVRS on BMI, lung function and health status (assessed by SF 36 questionnaire) were recorded at 3, 6, 12 and 24 months.

RESULTS

We found an overall increase in BMI after LVRS, which was significant up to 2 years. These changes correlated with the changes in FEV1 (R = 0.3, P < 0.01 6 months after LVRS) and diffusing capacity for carbon monoxide (DLCO) (R = 0.5, P < 0.01 6 months after LVRS). At 6 months, when the best results in health status were found, the patients were divided in a responders group (improved SF 36 score) and a non-responders group (same or worse SF 36 score) for each of the 8 domains of the SF 36. In 6 domains the non-responders showed no increase in BMI. In 6 domains the responders showed a significant increase in BMI.

CONCLUSION

LVRS significantly improves postoperative BMI, which correlates with improvements in DLCO and reflects changes in health status.

Effects of lung volume reduction surgery for emphysema on oxygen cost of breathing

BACKGROUND

Patients with severe pulmonary emphysema have a greatly increased oxygen cost of breathing (O(2) cost), and this is the cause of serious malnutrition, or respiratory cachexia, in such patients.

STUDY OBJECTIVES

To clarify the effect of lung volume reduction surgery (LVRS) on respiratory function and the nutritional state of these patients through a reduction in the O(2) cost of the respiratory muscles.

DESIGN

Prospective cohort study. Setting, patients, and interventions: Twenty-three patients who underwent LVRS in Tohoku University Hospital.

MEASUREMENTS

Pulmonary function and O(2) cost were measured perioperatively by utilizing a method of continuous dead space. In addition, we calculated the proportion of oxygen consumption (O(2)) of respiratory muscles to total O(2) (%O(2)resp) from the measured energy expenditure and the predicted values.

RESULTS

FEV(1) and arterial oxygen pressure increased after surgery while lung volume and dyspnea decreased (p < 0.01), and O(2) cost was also reduced from 0.044 to 0.026 log(mL/min)/(L/min) [p < 0.001]. Moreover, the change in O(2) cost had a strong negative correlation with that of FEV(1) (r = - 0.70, p < 0.001), and a moderate positive correlation with that of the ratio of residual volume to total lung capacity (r = 0.54, p < 0.01). %O(2)resp was 23.1% at rest and 55.5% at maximal ventilation. LVRS reduced %O(2)resp at maximal ventilation to 49.0% (p < 0.05), but %O(2)resp at rest did not decrease after surgery.

CONCLUSIONS

LVRS reduces energy expenditure of respiratory muscles especially during exercise by decreasing small airway obstruction and hyperinflated lung volume. This may reverse the malnourished state in end-stage emphysema.

Body weight and nutritional changes after reduction pneumoplasty for severe emphysema: a randomized study

BACKGROUND

The impact of reduction pneumoplasty on body weight and nutritional status has not previously been tested in a controlled study.

METHODS

We investigated 60 patients with severe emphysema who were randomly assigned to receive either reduction pneumoplasty (n = 30) or a 6-week respiratory rehabilitation program (n = 30). Nutritional status was evaluated by means of body mass index, triceps skin fold measurement, midarm muscle circumference, and biochemical blood values. Fat mass and fat-free mass were calculated by bioelectric impedance. Two treatment-related deaths occurred after reduction pneumoplasty and 1 death occurred after respiratory rehabilitation.

RESULTS

Functional and subjective improvements were significantly showed in reduction pneumoplasty group. Despite insignificant differences in energy intake, the reduction pneumoplasty group showed significant gain (P <.0001) relative to the respiratory rehabilitation group in mean weight changes at 3 months (1.82 +/- 2.63 kg vs -0.57 +/- 2.25 kg), 6 months (2.87 +/- 3.79 kg vs -1.11 +/- 2.64 kg), and 12 months (3.29 +/- 4.01 kg vs -0.95 +/- 1.90 kg). Both fat mass and fat-free mass increased after surgery, but only fat-free mass had a significant improvement (P =.001). Six-month weight gain in the reduction pneumoplasty group was significantly correlated with low baseline weight (rho = -0.437, P =.02) and residual volume reduction (rho = -0.446, P =.01). Total proteins (P =.003), albumin (P =.03), transferrin (P =.04), cholesterol (P =.003), hemoglobin (P =.01), triceps skin fold measurement (P <.0001), and midarm muscle circumference (P <.0001) were significantly increased only in the reduction pneumoplasty group. Conversely, in the respiratory rehabilitation group no nutritional index was significantly increased at 6 months after rehabilitation.

CONCLUSIONS

Body weight and nutritional status improved only after reduction pneumoplasty and not after respiratory rehabilitation, and this was significantly related to fat-free mass increment. In the reduction pneumoplasty group, the residual volume result was significantly correlated with postoperative weight gain.

Pulmonary cachexia

Weight loss is a frequent complication in patients with chronic obstructive pulmonary disease (COPD) and is a determining factor of functional capacity, health status, and mortality. Weight loss in COPD is a consequence of increased energy requirements unbalanced by dietary intake. Both metabolic and mechanical inefficiency contribute to the elevated energy expenditure during physical activity, while systemic inflammation is a determinant of hypermetabolism at rest. A disbalance between protein synthesis and protein breakdown may cause a disproportionate depletion of fat-free mass in some patients. Nutritional support is indicated for depleted patients with COPD because it provides not only supportive care, but direct intervention through improvement in respiratory and peripheral skeletal muscle function and in exercise performance. A combination of oral nutritional supplements and exercise or anabolic stimulus appears to be the best treatment approach to obtaining significant functional improvement. Patients responding to this treatment even demonstrated a decreased mortality. Poor response was related to the effects of systemic inflammation on dietary intake and catabolism. The effectiveness of anticatabolic modulation requires further investigation.

Lung volume reduction surgery and nutritional status in patients with severe emphysema

OBJECTIVE

We studied the short-term effect of lung volume reduction surgery on nutritional status including body composition and the relationship between preoperative nutritional status and postoperative morbidity.

METHODS

Subjects were 28 patients with emphysema who underwent bilateral thoracoscopic lung volume reduction surgery (23 simultaneously, 5 staged). Functional tests, body weight, and body composition were measured before and 6 months after surgery. Fat-free mass and fat mass were assessed by bioelectrical impedance analysis.

RESULTS

FEV1.0 improved 35.2% following surgery and maximal oxygen uptake 23.8%. Body weight and fat-free mass increased significantly after surgery, while fat mass was unchanged. Of the 23 undergoing simultaneous bilateral lung volume reduction surgery, 8 had major complications-3 required additional surgery to close air leaks, 3 required mechanical ventilation (> 72 hrs), and 2 developed postoperative infection. The preoperative percentage of ideal body weight and fat-free mass was significantly higher among patients without major complications.

CONCLUSIONS

Bilateral lung volume reduction surgery increases fat-free mass and provides functional improvement for underweight patients with severe emphysema. We found fat-free mass and body weight to be good predictors of unacceptable postoperative complications following bilateral lung volume reduction surgery.

Extrapulmonary effects of chronic obstructive pulmonary disease

Although airflow obstruction is the most obvious and most studied manifestation of chronic obstructive pulmonary disease (COPD), it should not be overlooked that COPD, particularly in its later stages, is associated with many extrapulmonary features that contribute to the morbidity, reduced quality of life, and, possibly, mortality of this disease. We review here the literature on skeletal muscle dysfunction, osteoporosis, and weight loss in COPD, with particular attention to possible approaches to their management. Patients with COPD may also have other extrapulmonary effects such as hormonal abnormalities that could probably be corrected, but less is known about them. COPD, therefore, should be regarded as a systemic disorder. Its systemic manifestations should not be overlooked in the overall care of the patient, because there are important ways in which they can be addressed.

Lung volume reduction surgery for emphysema

Over the past decades, extensive literature has been published regarding surgical therapies for advanced COPD. Lung-volume reduction surgery would be an option for a significantly larger number of patients than classic bullectomy or lung transplantation. Unfortunately, the initial enthusiasm has been tempered by major questions regarding the optimal surgical approach, safety, firm selection criteria, and confirmation of long-term benefits. In fact, the long-term follow-up reported in patients undergoing classical bullectomy should serve to caution against unbridled enthusiasm for the indiscriminate application of LVRS. Those with the worst long-term outcome despite favourable short-term improvements after bullectomy have consistently been those with the lowest pulmonary function and significant emphysema in the remaining lung who appear remarkably similar to those being evaluated for LVRS. With this in mind, the National Heart, Lung and Blood Institute partnered with the Health Care Finance Administration to establish a multicenter, prospective, randomized study of intensive medical management, including pulmonary rehabilitation versus the same plus bilateral (by MS or VATS), known as the National Emphysema Treatment Trial. The primary objectives are to determine whether LVRS improves survival and exercise capacity. The secondary objectives will examine effects on pulmonary function and HRQL, compare surgical techniques, examine selection criteria for optimal response, identify criteria to determine those who are at prohibitive surgical risk, and examine long-term cost effectiveness. It is hoped that data collected from this novel, multicenter collaboration will place the role of LVRS in a clearer perspective for the physician caring for patients with advanced emphysema.

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.