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Ann Thorac Surg 2000;70:948-953
© 2000 The Society of Thoracic Surgeons

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Original articles: general thoracic

Reduction pneumoplasty versus respiratory rehabilitation in severe emphysema: a randomized study

^a Division of Thoracic Surgery, Tor Vergata University, Rome, Italy
^b Division of Pulmonary Medicine and Respiratory Rehabilitation, Ospedale Cartoni, Rocca Priora, Italy
^c Department of Experimental Medicine and Pathology, La Sapienza University, Rome, Italy

Address reprint requests to Dr Pompeo, Cattedra di Chirurgia Toracica, Università Tor Vergata, Ospedale S. Eugenio, P.le Umanesimo, 10, 00144 Rome, Italy
e-mail: pompeo{at}med.uniroma2.it

Presented at the Thirty-sixth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 31–Feb 2, 2000.

	Abstract

Top Footnotes Abstract Introduction Material and methods Results Comment Appendix. Pulmonary Emphysema... References

 
Background. The purpose of the study was to determine in a prospective randomized trial the independent short-term physiologic impact of reduction pneumoplasty (RP) on respiratory rehabilitation (RR).

Methods. Sixty patients eligible for RP were randomly selected by computer to receive either RP (n = 30) or comprehensive RR (n = 30). Pulmonary function tests, analysis of blood gas levels, measurement of respiratory muscle strength (maximal inspiratory and expiratory pressures), 6-minute walk test (6MWT), and incremental treadmill test (ITT), were performed at baseline and at 3 and 6 months.

Results. Two treatment-related deaths occurred after RP and one after RR. At 6 months dyspnea index, maximal inspiratory pressure, 6MWT, ITT, and PaO₂ were significantly improved in both groups whereas forced expiratory volume in 1 second and residual volume were significantly improved only in the surgical arm. In addition at 6 months, dyspnea index, 6MWT, maximal ITT, and PaO₂ improved significantly more after RP than after RR.

Conclusions. In our study short-term improvements in dyspnea index, oxygenation, inspiratory muscle strength, and exercise capacity occurred after either RP and RR. However dyspnea index, PaO₂, and exercise capacity improved more after RP than after RR whereas pulmonary function improved only after RP.

	Introduction

Top Footnotes Abstract Introduction Material and methods Results Comment Appendix. Pulmonary Emphysema... References

 
Reduction pneumoplasty (RP) is being actively investigated as a palliative surgical treatment for selected patients with severe emphysema. The operation involves nonanatomic resection of useless hyperinflated lung aimed at improving respiratory mechanics, lung recoil pressure, and ventilation perfusion matching [1].

Several studies have demonstrated that after RP significant improvement in lung function exercise capacity and subjective dyspnea may occur, and that these improvements may be maintained for 2 to 4 years [2, 3]. Nonsurgical care of severely affected patients despite maximal bronchodilator therapy includes enrollment in comprehensive respiratory rehabilitation (RR) programs that may also improve dyspnea and functional exercise capacity [4].

Currently, RR is carried out in many centers as a preoperative to postoperative adjunct to RP with the aim of reducing morbidity and optimizing operative results. The question therefore has been raised as to what portion of the measured benefits is attributable to the operation per se and what portion is attributable to the ongoing rehabilitation. One randomized trial compared bilateral RP with RR in patients with severe emphysema [5]. In that study improvement in lung function measures was achieved in the surgical arm only, whereas rehabilitation showed a limited role in improving aerobic exercise performance. However, in that trial all recruited patients received a prerandomization course of RR [5] that may have had a bearing on the operative outcome.

We conducted a prospective, randomized, controlled study examining the effects of sole RP versus sole RR on subjective dyspnea, lung function, gas exchange, respiratory muscle strength, and exercise capacity. Our goal was to determine the independent short-term physiologic impact of RP on maximal medical therapy including RR.

	Material and methods

Top Footnotes Abstract Introduction Material and methods Results Comment Appendix. Pulmonary Emphysema... References

 
The study was started in January 1996 and was closed in January 1999. Written informed consent was obtained from all patients who took part. Sixty patients who met the entry criteria (Table 1) were randomized by computer into two groups: 30 patients underwent video-assisted thoracoscopic RP and 30 patients underwent a structured supervised exercise rehabilitation program for a minimum of 6 weeks. No patient in the surgical arm underwent preoperative or postoperative rehabilitation.

Exercise tolerance was assessed by 6-minute walk test (6MWT) with standardized encouragement and by maximal incremental treadmill test (ITT). Incremental treadmill test was performed with stepwise increase of both velocity and gradient until the symptom-limited maximum, according to a modified Bruce protocol.

At baseline and during the follow-up visits dyspnea was rated according to the modified Medical Research Council Score [7]. Complete symptomatic and functional assessment was repeated 3 and 6 months after completion of treatment.

Surgical technique
The operation was directed at reducing 20% to 30% of the lung volume by excising functionally useless and hyperinflated lung tissue. Patients assigned to the surgical arm underwent tailored unilateral or bilateral RP by means of video-assisted thoracoscopic surgery. The main indication for unilateral RP was the finding of an asymmetric distribution of emphysema in the lungs [8]. Extrapleural dissection was carried out selectively in patients with dense adhesions [9]. Staple resection of target areas was performed routinely by excising a single strip of lung tissue. Patients were extubated routinely in the operating room.

Respiratory rehabilitation
The aim of the outpatient rehabilitation program was to optimize the performance of daily living activities by improving exercise capacity. The program entailed 3-hour supervised sessions over 5 days per week for at least 6 weeks. The first half of each session included educational activity such as breathing retraining, chest clearance, energy conservation, nutritional and medication education, and psychosocial support. The second half of each session entailed physical conditioning including inspiratory resistive exercises, upper extremity training, and lower extremity training.

Study design and statistical methods
The primary outcome measures chosen were forced expiratory volume in 1 second (FEV₁) and maximal exercise capacity (ITT). Trial size was originally determined by the number of patients necessary to yield, by a nonparametric two-sided test, with a power of 0.9 and with an error of 0.05, a 1.25-fold difference in median FEV₁ or maximal ITT. The close-out period was set at 6 months assuming that for either treatment peak improvements should be reached within the first 6 months. Such a limited duration of the trial was also preferred for ethical purposes so as to eventually allow crossover of unimproved patients to the most effective therapy after final follow-up evaluation. Group descriptive statistics are presented as mean ± SD. The Wilcoxon rank sum test, the Mann-Whitney test, and Friedman’s analysis of variance were used as appropriate due to the non-normal distribution of data and the limited sample size. Frequencies were compared with the Fisher’s exact test.

	Results

Top Footnotes Abstract Introduction Material and methods Results Comment Appendix. Pulmonary Emphysema... References

 
Of the 237 patients screened, 60 were randomized and 55 completed the 6-month study (Fig 1). Among the 125 ineligible patients 39 had prevailing intrinsic disease of the airway or asthma, 35 did not meet entry spirometric (n = 24) or radiologic (n = 11) criteria, 22 had clinically significant comorbidities, 14 were still smoking, 8 did not meet nutritional status (n = 4) or exercise performance (n = 4) requirements, and 7 were older than 75 years old.

View larger version (32K): [in this window] [in a new window]   Fig 1. Outcome of 237 patients screened.

Medical arm data
All patients completed a minimum of 75% of the training sessions. Five patients underwent prolonged rehabilitation for up to a total of 10 weeks. Seven patients, living too far away from hospital to comply with the outpatient program, received inpatient rehabilitation. No patient died during the rehabilitation period. Three patients withdrew following the 3-month evaluation due to unsatisfactory symptomatic improvement and 1 of these patients eventually died due to respiratory failure 2 months later. Four patients required hospitalization during the follow-up due to exacerbation of symptoms and worsening hypoxemia (n = 3) or pneumonia (n = 1). All these patients were subsequently discharged uneventfully and completed the follow-up evaluation.

There was no difference between the surgical and medical arm in treatment-related 1-month or 6-month mortality (2 patients versus 1 patient, p = NS) and 6-month morbidity (3 patients versus 4 patients, p = NS). On the other hand 1-month morbidity was significantly higher in the surgical (16 patients versus none; p < 0.00001).

In the surgical arm a significant improvement occurred at 6-month assessment in all evaluated parameters excepted for PaCO₂ and MEP. Differently, in the medical arm only dyspnea index, MIP, and PaO₂ were improved significantly after 6 months. Intergroup comparison revealed a more significant improvement in dyspnea index, PaO₂, 6MWT, and ITT after RP than after RR (Table 4). Figures 2, 3, and 4 illustrate the behavior of the 6MWT, the ITT, and the FEV₁ at baseline and 3 and 6 months after completion of treatment. The 6MWT and the ITT changed significantly during the follow-up in both groups (ANOVA; p < 0.0001) whereas the FEV₁ changed significantly only in the surgical group (ANOVA; p < 0.0001). However, whereas in the surgical arm the results of 6MWT and ITT continued to improve with time peaking at 6 months, in the medical arm the results of both tests peaked at 3 months and slightly worsened at 6 months. At last follow-up oxygen requirements improved significantly after RP compared with baseline results (8 patients versus 16 patients on oxygen; p = 0.04). On the other hand, no change was noted in exercise oxygen requirements in the medical arm (17 patients versus 17 patients on oxygen; p = NS).

View larger version (18K): [in this window] [in a new window]   Fig 2. Results of the measurements of forced expiratory volume in 1 second. (RP = reduction pneumoplasty; RR = respiratory rehabilitation.)

View larger version (19K): [in this window] [in a new window]   Fig 3. Results of the 6-minute walk test. (RP = reduction pneumoplasty; RR = respiratory rehabilitation.)

View larger version (18K): [in this window] [in a new window]   Fig 4. Results of the maximal incremental treadmill test. (RP = reduction pneumoplasty; RR = respiratory rehabilitation.)

	Comment

Top Footnotes Abstract Introduction Material and methods Results Comment Appendix. Pulmonary Emphysema... References

 
Our main finding was that pulmonary function measures and oxygen requirements were significantly improved after RP whereas they remained unchanged after RR. In particular, by means of tailored unilateral and bilateral operation we have achieved a 0.46-L increase in FEV₁ that compares with the best results reported after bilateral RP [10]. This feature is consistent with the previous observation that after unilateral RP, patients with asymmetric emphysema may have similar FEV₁ improvement to those undergoing bilateral operation [6, 8]. A second feature is that symptomatic dyspnea, 6MWT, maximal ITT, MIP, and PaO₂ were significantly improved in both study arms. Recently, Criner and colleagues [5] reported the results of a controlled randomized trial comparing prolonged RR versus rehabilitation and bilateral RP. In accordance with our findings, in that study, pulmonary function tests improved only in the surgical arm; however, in the medical arm only total exercise time at maximal ITT increased significantly in contrast to the wider pattern of improvements we observed after RR. This finding may depend in part on three differences between the studies: First, because none of our patients received rehabilitation before randomization, a greater difference in outcome measures may be explained by the lack of possible prerandomization improvements. Second, our patients were less severely obstructed and had better baseline 6MWT scores and these features may be related to improved response to rehabilitation [11]. Lastly, other differences existed between the studies in design, methods, duration, intensity of exercise training, and outcome measures.

Several reports have shown that comprehensive RR does not modify spirometry lung volumes but may improve dyspnea, exercise capacity [4, 12, 13], and respiratory muscle strength [14]. Nonetheless, our data have indicated that greater improvements in dyspnea index, exercise capacity (6MWT and ITT), and PaO₂ occurred after sole RP than after RR. In an era of cost-effectiveness concerns, this result suggests that RR, although useful, might not be necessary as a routine adjunct to RP. On the other hand, the possibility that combined RR plus RP may act in a synergistic or complementary way in determining outcome, implies that further studies comparing sole RP versus combined RP and RR are warranted.

Significant improvement in subjective dyspnea has occurred after either RP or RR [2, 4, 12, 13]. This symptom has proved to correlate better with general health status than with the degree of airway obstruction [15]. However, Brenner and colleagues [16] found that after RP improvement in FEV₁ was correlated with improvement in dyspnea scores. Supposed mechanisms of improvement include reduced thoracic hyperinflation and reduced mechanical constraints on lung volume expansion that are both related to a reduction in RV [17]. These mechanisms represent a possible explanation of the greater symptomatic improvement we have observed after RP, because pulmonary function measures and static lung volumes did not change after RR.

Our data confirm prior reports of significant improvements in 6MWT distance or maximal ITT after either RP or RR. The difference that we noted in exercise performance after operative or medical therapy may be due to different mechanisms of improvement. Increased motivation has been conceived as possibly translating into improved exercise capacity after RR. However, increased peak work rate, peak maximal oxygen uptake [18], and the recent evidence of increased levels of aerobic enzymes of leg muscles noted after RR [19] suggest a true physiologic training effect. Differently, after RP increased maximal exercise workload, maximal oxygen uptake, maximal tidal volume, and maximal ventilatory capacity have been proved to be associated with improved FEV₁ and decreased RV that suggest improvements in respiratory mechanics [20].

Studies examining the effects of RP or RR on respiratory muscle strength have reported conflicting results [21–23]. Recently, Criner and colleagues [24] showed no improvements in MIP or transdiaphragmatic pressures after RR, whereas a significant increase of MIP was evidenced after RP. Such increase tended to correlate with reduction in RV and is likely due to mechanisms that include an increased length, improved geometry, and improved mechanical effectiveness of inspiratory muscles. We have found that MIP increased significantly after either RR or RP, although RV decreased only after operative treatment. We hypothesized that improvements in respiratory muscle strength after RR might be addressed to a positive effect of breathing retraining exercises that may have reduced dynamic hyperinflation, to a training effect on respiratory muscles strength, or both [18].

Reduction pneumoplasty has showed variable effect on gas exchange. Cooper and colleagues [10] reported a mean increase of 6 mm Hg in PaO₂ at 6 months but no significant differences in PaCO₂. Differently, Criner and colleagues [5] found a reduction of 4 mm Hg in PaCO₂ but no effect on PaO₂. These improvements are consistent with a better regional ventilation or perfusion matching following the recruitment of previously compressed lung that is composed of normally perfused alveolar units [14]. In accordance with Cooper and colleagues [10], we found an increase of 5 mm Hg in PaO₂ after RP but no effect on PaCO₂ at the last follow-up. The smaller and yet significant increase in PaO₂ observed in the medical arm is more difficult to explain because usually RR had no effect on gas exchange. It is conceivable that optimized chest clearance realized during rehabilitation may have improved ventilation-perfusion matching in those patients who did not receive maximized medical care before study.

In our study population there was no difference between the study arms in 1-month mortality whereas, as expected, 1-month morbidity was significantly greater after RP. On the other hand, the higher 6-month morbidity noted after RR and the finding that 44.4% of medical arm patients underwent RP after completion of the study follow-up, suggest that RP is superior to RR in determining satisfactory and stable improvements; furthermore RP effectively reduced the number of late complications in patients with severe emphysema. Reduction pneumoplasty, however is not without risk for increased perioperative morbidity compared with standard medical therapy.

In conclusion, this controlled randomized study confirms short-term improvements in subjective dyspnea, lung function, gas exchange, inspiratory muscle strength, and exercise capacity after RP for severe emphysema. In addition we found that RR may also be associated with significant improvements in dyspnea, exercise capacity, inspiratory muscle strength, and oxygenation, although these improvements appear to be smaller and less stable than those of RP. Limitations of our study relate to the small number of patients and the short-term assessment of the results that has denied the possibility of achieving comparative data on duration of benefits and survival. Hopefully, more definitive data of the risks, benefit, effects on survival, and durability of RP will be provided in the near future by the results of larger multicenter studies such as the National Emphysema Treatment Trial (NETT) [25].

	Footnotes

Top Footnotes Abstract Introduction Material and methods Results Comment Appendix. Pulmonary Emphysema... References

 
^* The members of the Pulmonary Emphysema Research Group are listed in the Appendix.

	Appendix. Pulmonary Emphysema Research Group (PERG)

 

Clinical Centers Università Tor Vergata, Roma: Tommaso Claudio Mineo, MD (Principal investigator and coordinator); Eugenio Pompeo, MD; Vincenzo Ambrogi, MD; Benedetto Cristino, MD; Alessandro F Sabato, MD; Mario Dauri, MD; Mauro Polzoni, MD; Franco Turani, MD; Domenico Curatola, MD; Maurizio Visaggio, MD; GianLuigi Sergiacomi, MD; Cesidio Cipriani, MD; Sergio Villaschi, MD; Paolo Rossi, MD; Lucia Senis, MD Ospedale "Cartoni" Rocca Priora: Mario Marino, MD; Giuseppe Matteucci, MD; Filippo DePadova, MD, Cesare Maria Fiorani, MD Università "La Sapienza," Roma: Italo Nofroni, BS; Andrea Fabbri, MD Istituto Nazionale della Nutrizione, Roma: Angela Polito, PhD Ospedale Civile di Frascati: Luigi Casella, MD Ospedale "St. Giuseppe" Marino: Franz Finocchio Thorel, MD Ospedale "Calai," Gualdo Tadino: Marcello Paci, MD Ospedale Civile di Agnone: Nicola Iavicoli, MD Ospedale Civile di Lecce: Corrado Sorrenti, MD; Gaetano Greco, MD Ospedale Forlanini, Roma: Salvatore Mariotta, MD Ospedale St. Eugenio, Roma: Gaetano Aiello, MD; Paola Codato, MD; Guido Sciarra, MD; Nello Giovannone, MD; Gianpaolo Giovannone, MD

Pretreatment to posttreatment changes: ^a Wilcoxon test, p < 0.0001;^b p < 0.0002; ^c p < 0.01.

FEV₁ = forced expiratory volume in 1 second; FVC = forced vital capacity; ITT = incremental treadmill test; MEP = maximal expiratory pressure; MIP = maximal inspiratory pressure; 6MWT = 6-minute walk test; RV = residual volume.

Source of funding: The Pulmonary Emphysema Research Group is supported by a Grant of Ministero dell’Università e della Ricerca Scientifica e Tecnologica No. 9906274194-06.

	References

Top Footnotes Abstract Introduction Material and methods Results Comment Appendix. Pulmonary Emphysema... References

 

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				M. Tutic, K. E. Bloch, D. Lardinois, T. Brack, E. W. Russi, and W. Weder Long-term results after lung volume reduction surgery in patients with {alpha}1-antitrypsin deficiency J. Thorac. Cardiovasc. Surg., September 1, 2004; 128(3): 408 - 413. [Abstract] [Full Text] [PDF]

				D. Ost, L. Glassman, A. M. Fein, and P. Marcus Innovations in Lung Volume Reduction: The Non-Cutting Edge Chest, July 1, 2004; 126(1): 6 - 9. [Full Text] [PDF]

				T.C. Mineo, V. Ambrogi, E. Pompeo, S. Elia, D. Mineo, P. Bollero, and I. Nofroni Impact of lung volume reduction surgery versus rehabilitation on quality of life Eur. Respir. J., February 1, 2004; 23(2): 275 - 280. [Abstract] [Full Text] [PDF]

				R. A. Maxfield New and Emerging Minimally Invasive Techniques for Lung Volume Reduction Chest, February 1, 2004; 125(2): 777 - 783. [Abstract] [Full Text] [PDF]

				M. Decramer Treatment of chronic respiratory failure: lung volume reduction surgery versus rehabilitation Eur. Respir. J., November 16, 2003; 22(47_suppl): 47s - 56s. [Abstract] [Full Text] [PDF]

				K. Jorgensen, E. Houltz, U. Westfelt, F. Nilsson, H. Schersten, and S.-E. Ricksten Effects of Lung Volume Reduction Surgery on Left Ventricular Diastolic Filling and Dimensions in Patients With Severe Emphysema Chest, November 1, 2003; 124(5): 1863 - 1870. [Abstract] [Full Text] [PDF]

				E.W. Russi, K.E. Bloch, and W. Weder Lung volume reduction surgery: what can we learn from the National Emphysema Treatment Trial? Eur. Respir. J., October 1, 2003; 22(4): 571 - 573. [Full Text] [PDF]

				B F Meyers and G A Patterson Chronic obstructive pulmonary disease * 10: Bullectomy, lung volume reduction surgery, and transplantation for patients with chronic obstructive pulmonary disease Thorax, July 1, 2003; 58(7): 634 - 638. [Abstract] [Full Text] [PDF]

				National Emphysema Treatment Trial Research Group A Randomized Trial Comparing Lung-Volume-Reduction Surgery with Medical Therapy for Severe Emphysema N. Engl. J. Med., May 22, 2003; 348(21): 2059 - 2073. [Abstract] [Full Text] [PDF]

				National Emphysema Treatment Trial Research Group Cost Effectiveness of Lung-Volume-Reduction Surgery for Patients with Severe Emphysema N. Engl. J. Med., May 22, 2003; 348(21): 2092 - 2102. [Abstract] [Full Text] [PDF]