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a Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, Missouri
b Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, Missouri
c Division of Thoracic Surgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania
Accepted for publication March 18, 2008.
* Address correspondence to Dr Meyers, Washington University School of Medicine, Department of Cardiothoracic Surgery, 3108 Queeny Tower, One Barnes-Jewish Hospital Plaza, St. Louis, MO 63110–1013 (Email: meyersb{at}wustl.edu).
Presented at the Forty-second Annual Meeting of The Society of Thoracic Surgeons, Chicago, IL, Jan 30–Feb 1, 2006.
| Dr Cooper discloses that he has a financial relationship with Synovis.
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Abstract |
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Methods: Between January 1993 and December 2006, 43 consecutive patients underwent ULVRS. The study excluded patients undergoing giant bullectomy. Relative contraindications for BLVRS were unilateral emphysema, 21; unilateral emphysema plus other factors, 2; and other factors alone, 10. Preoperative pulmonary rehabilitation was required. Postrehabilitation data were used as the baseline for analyses. Outcome measurements for ULVRS were compared with BLVRS results.
Results: After ULVRS, the mean increase in forced expiratory volume in 1 second (FEV1) from postrehabilitation values was 32% at 6 months (p 
0.001) and 28% at 3 years (p = 0.036). The FEV1 was not significantly improved at 5 years. The mean reduction in residual volume after ULVRS was 23% at 6 months (p 0.001) and 38% at 5 years (p = 0.001). Supplemental oxygen requirements declined initially postoperatively. One patient (2%) died in the hospital. The 90-day mortality was 0%. Kaplan-Meier survival after ULVRS was 97.7%, 80.9%, and 45.5%, at 1, 3, and 5 years.
Conclusions: ULVRS produces improvements in pulmonary function, exercise capacity, and quality of life with an acceptable morbidity and mortality in patients for whom BLVRS is contraindicated, but the benefits are of lower magnitude than those achieved with BLVRS.
Emphysema is the fourth leading cause of death in the United States and is a leading cause of disability. The primary treatment remains medical management, including smoking cessation, supplemental oxygen administration, bronchodilators, and exercise rehabilitation. For selected patients, surgical options include bullectomy, lung volume reduction surgery (LVRS), and lung transplantation.
In 1958 Otto Brantigan and colleagues [1] proposed LVRS and suggested that partial lung resection could provide symptomatic and functional improvement in highly selected patients with emphysema. Initially, this procedure did not receive widespread acceptance because of high mortality and modest clinical benefit without objective documentation of benefit. In 1993 Cooper and colleagues [2] reintroduced LVRS by using a median sternotomy approach and incorporating bilateral pulmonary resection.
We have reported the long-term outcome of the initial 250 consecutive bilateral LVRS (BLVRS) performed at our institution. Our report agreed with many other single-center cohort studies in concluding that there is significant functional improvement for highly selected emphysema patients [3]. We continue to favor a bilateral approach, when possible, in order to achieve the maximum benefit with one procedure. However, for patients who meet the criteria for LVRS, but have a relative or absolute contraindication to a bilateral procedure, we have used a unilateral LVRS (ULVRS) approach, which has been demonstrated by others to produce beneficial results [4, 5]. We conducted the present retrospective study to describe the outcomes of ULVRS in patients with contraindications for BLVRS.
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Material and Methods |
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Patients were selected for ULVRS on the basis of disabling dyspnea, marked thoracic hyperinflation, heterogeneous target areas for resection, and a relative contraindication for BLVRS. Specific reasons for unilateral procedures included a marked asymmetrical unilateral distribution of disease in 22 patients, asymmetrical disease plus other factors in 8, other factors (such as previous thoracotomy or pleurodesis, or both) without asymmetry of disease in 9, an intraoperative decision due to adhesions in 3, and previous unilateral thoracic radiotherapy in 1. In the three cases of intraoperative decision making, a bilateral procedure was intended or considered, but dense adhesions led to the creation of substantial air leaks after the first side was completed and the procedure was stopped after one side. In all other patients, the decision for a unilateral procedure was made preoperatively.
Preoperative Assessment
We generally offered LVRS to patients with marked impairment and disability despite optimal medical therapy, a suitable clinical and physiologic profile, and a favorable radiologic pattern of emphysema. Critical selection criteria included disabling dyspnea due to marked airflow obstruction, thoracic hyperinflation, and emphysema that was heterogeneously distributed within each lung to provide target areas for resection. We excluded patients with a predominance of airways disease, an inadequate amount of lung spared from severe emphysema as demonstrated on computed tomography (CT) scan, or who had a major comorbidity. Patients with symptoms suggestive of pulmonary hypertension underwent right heart catheterization. Patients with a systolic pulmonary artery pressure exceeding 45 mm Hg or a mean pulmonary artery pressure exceeding 35 mm Hg were excluded. With rare exception, patients accepted for BLVRS or giant bullectomy were excluded from this study.
Patients underwent preoperative assessment for cardiac ischemia. Chest roentgenograms were used to screen for emphysema location and severity, hyperinflation, and other disorders. High-resolution chest CT scans were used to identify the severity of the emphysema, the heterogeneity of the distribution of emphysematous destruction, and other findings such as lung nodules, bronchiectasis, and pleural disease. Radionuclide ventilation-perfusion lung scans were used to look for a reduction in blood flow and abnormal ventilation in the potential surgical target areas for resection.
All patients were required to participate in a preoperative pulmonary rehabilitation program for a minimum of 6 to 8 weeks. The week before the operation, the patients were reassessed with an interval history and physical examination, chest roentgenogram, complete pulmonary function tests, arterial blood gases, 6-minute walk test, and quality-of-life questionnaires. The postrehabilitation preoperative data were used as the baseline for comparisons with postoperative data.
Pulmonary function tests were performed with a Medgraphics System 1085 (Medical Graphics Corporation, St. Paul, MN). Lung volumes were determined by plethysmography, and diffusing capacity for carbon monoxide (DLCO) was measured with the single breath technique. Postbronchodilator spirometry and lung volume data are reported. During the 6-minute walk test, supplemental oxygen was administered by nasal cannula as needed to maintain the arterial oxygen saturation at 90% or higher.
Follow-Up
Patients were invited and encouraged to return for follow-up immediately postoperatively, at 3 months, 6 months, and then annually thereafter. Evaluation at these clinical follow-up visits included interval history, physical examination, and limited laboratory assessments consisting of chest roentgenograms, pulmonary function testing, arterial blood gasses, and 6-minute walk tests. A complete panel of pulmonary function testing was done at our institution, and an abbreviated battery of tests from other institutions was used for data analysis.
Dyspnea, general health-related quality of life, and each patient's satisfaction with the operation were assessed with questionnaires that were provided either onsite or through the mail. Patients completed self-administered general questionnaires including the Medical Outcomes Study 36-Item Short-Form (SF-36) Health Survey [6]. In this study, we report the physical functioning (PF) scale scores, which range from 0 (worst) to 100 (best). The physical component summary score is standardized so that the general population has a mean ± standard deviation (SD) score of 50 ± 10. A 10-point change in the PF score is considered clinically important.
Dyspnea was quantified by the modified Medical Research Council (MRC) of Great Britain Dyspnea Scale. The scale has 5 integer grades, 0 through 4, that describe the level of activity that provokes dyspnea; lower numbers indicate less dyspnea. A 1-point change in the dyspnea scale is considered clinically important. Postoperative patient overall satisfaction was measured with a question, "Please assess your overall satisfaction with the operation based on how you feel at the present time." Patients were asked to choose one of five possible responses: poor, fair, good, very good, and excellent.
Operative Technique
A unilateral muscle-sparing thoracotomy was used in 41 of 43 procedures. In 2 patients we performed a median sternotomy to surgically assess both sides but chose to perform ULVRS. We used successive application of a linear stapler, reinforced with bovine pericardial strips, to typically excise approximately 80% of the upper lobe for procedures on the right and approximately 60% of the upper lobe on the left. We usually sought to spare the lingula, which is usually better preserved than the superior subdivision of the upper lobe.
In 7 patients with severe lobar parenchymal destruction and complete fissures, an anatomic lobectomy was performed rather than wedge excisions. One patient underwent left pneumonectomy on the basis of an intraoperative decision that the remaining lung was not sufficiently functional to merit saving it after upper and lower lobe wedge resections. A large residual apical space was left after resection in 4 patients, and we created a pleural tent to allow the apical pleura to drop down to the upper surface of the remaining lung. All patients were extubated in the operating room or in the recovery area. Other than the site of chest entry and the unilateral approach, we use a similar surgical approach for bilateral procedures [2, 3].
Postoperative Management
The standard postoperative management protocol for LVRS patients in our center has been previously described [2, 3]. We typically aimed to achieve adequate postoperative pain management by placing an epidural catheter at the T4 level postoperatively. This has reduced the need for intraoperative systemic narcotics and has provided optimal pain relief without excessive respiratory depression. Patients were cared for on a thoracic step-down unit that has experienced thoracic surgical nurses and physiotherapists who assist with vigorous chest physiotherapy and ambulation. Patients typically began exercising on postoperative day 1. We also performed aggressive bedside bronchoscopy for any signs of respiratory distress or ineffective cough.
Statistical Analysis
Continuous variables are expressed as mean ± SD unless otherwise specified, and categoric data are expressed as counts and proportions. Comparisons were done with paired, two-tailed t tests for means of normally distributed continuous variables and Wilcoxon rank sum tests for skewed data. Either the 
2 or the Fisher exact test was used to compare categoric data. Kaplan-Meier analysis was used to estimate survival. Follow-up was censored for end of study, loss to follow-up, and lung transplantation. All data analyses were done using SYSTAT 11.0 software (SYSTAT Software Inc, Richmond, CA). Statistical significance was set at p < 0.05, and adjustments were not made for multiple comparisons.
A propensity analysis was performed to select a less biased subset of the BLVRS cohort with which to compare the 43 ULVRS patients [7, 8]. For this analysis, a logistic regression was performed on the 43 ULV patients and 250 contemporaneous BLVRS patients to identify factors associated with group membership in either the ULVRS or BLVRS groups. Propensity scores were calculated for all patients, and 43 BLVRS patients were then selected in a 1:1 fashion with each ULVRS patients according to adjacent or identical propensity scores to obtain the matched cohort. We compared outcomes of the 43 ULVRS patients and both the unmatched 250-patient BLVRS cohort and the 43-patient propensity-matched BLVRS cohort.
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Results |
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The average age of the 43 patients undergoing ULVRS was 66.3 ± 7 years, and 29 (67.4 %) were men. All patients had a history of tobacco use. The selected side of intervention was the right in 26 patients and the left in 17 patients.
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Reexploration was required in 2 patients (4%), one of whom had a prolonged air leak. The other patient other underwent thoracotomy for an empyema caused by the perforation of an esophageal diverticulum. The esophagopleural fistula was repaired and the patient survived for 6 months but died before leaving the hospital. All the operative morbidities are listed in Table 1. The hospital length of stay (LOS) was a median of 8 days (interquartile range [IRQ], 6 to 12 days).
Follow-Up Status
During the median follow-up of 4.7 years (IQR, 3.1 to 7.1 years; mean, 5.4 years), 34 (79%) of the treated patients died. Their deaths were attributed to respiratory failure in 28 (82%), other specific causes in 4 (12%), and unknown causes in 2. The median time to death after ULVRS was 4.9 years. The Kaplan-Meier survival estimate at 5 years after ULVRS was 45.5% (Fig 1). One patient, who had no complications related to the ULVRS, subsequently underwent lung transplantation at 5.5 years after ULVRS. None of the 43 patients underwent a subsequent contralateral LVRS procedure.
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0.001) and 28% at 3 years (p = 0.036). At 5 years there was no longer statistical evidence of an improved FEV1. Figure 2
shows histograms of the number of patients experiencing various degrees of improvement or decline at 1, 3, and 5 years postoperatively. Residual volume was significantly reduced after ULVRS, with a mean reduction of 23% at 6 months (p 0.001) and 38% at 5 years (p = 0.001). The average improvement above baseline persisted for 5 years.
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Comment |
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This study supports that BLVRS, when appropriate, should be preferred over ULVRS because the improvements of pulmonary function are better after BLVRS than after ULVRS [4, 5, 9]. However, patients undergoing ULVRS have clinically meaningful improvements that last for years; thus, ULVRS should be considered in patients that have contraindications to BLVRS.
Our results show that patients with end-stage emphysema who fulfill the criteria for LVRS appear to benefit after ULVRS. We found that the increase in FEV1 and decrease in residual volume occurred primarily during the first year after ULVRS, and despite the inevitable progression of chronic obstructive pulmonary disease (COPD), measurable benefit appeared to last through 5 years in those who survived to that point. Although the initial increase in FEV1 was greater after BLVRS compared with ULVRS, the rate of decline may be faster for BLVRS patients compared with ULVRS because both appear to reach the preoperative level of function at about 5 years postoperatively.
We compared our current morbidity and mortality with the unmatched cohort of 250 BLVRS patients and could not demonstrate a difference. The hospital mortality of 2.3% shows that ULVRS is reasonably safe and has an acceptable risk. A randomized controlled trial of ULVRS vs medical therapy or ULVRS vs BLVRS would best show the survival effects of ULVRS.
The Center for Medicare Services (CMS) has resumed reimbursing for BLVRS in selected CMS-approved centers, but currently, CMS does not reimburse for ULVRS. The decision to resume funding for BLVRS was based on the results of the National Emphysema Treatment Trial (NETT). Because that trial did not include any unilateral operations and no other trial to study unilateral procedures appears to be looming, any further consideration by CMS to cover ULVRS will be partly dependent on the reporting of individual case series from LVRS centers [10–13]. This report is, in part, an attempt to add to such data to allow further consideration of ULVRS in appropriate patients.
One limitation of our study is that our selection of patients for ULVRS was partly subjective. Without a system to objectively classify patients preoperatively into the appropriate group, the results observed at our institution might not be generalized to other programs that might use different criteria to assign ULVRS. We found it quite a challenge to retrospectively review operative reports and radiology reports and images from the early experience at our institution and clearly identify a case as a ULVRS vs a bullectomy. In fact, many cases were reviewed and rejected from analysis after the oral presentation of these results, because on closer inspection they were determined to be bullectomy operations.
Another limitation is that the comparison between ULVRS and BLVRS is slightly biased. We have used propensity analysis to reduce such bias. Because we did not capture data on all possible differences between the groups, the propensity analysis does not completely remove bias.
In conclusion, even though we prefer bilateral lung volume reduction operations for suitable patients with end-stage emphysema, unilateral procedures should be considered an alternative in selected appropriate patients with contraindications to a bilateral procedure. As in the BLVRS series, careful patient selection, rigorous preoperative preparation, and detailed postoperative care are necessary for the success of ULVRS.
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Discussion |
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TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionReferences |
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DR SULTAN: To answer your first question, I think in our patients, this is a special subgroup of patients who have unilateral emphysema, so when we do resection of that unilateral abnormal lung, the other side is still better; so in the long run, they tend to do better. That is one reason. The other reason is with unilateral LVRS, what we are doing effectively is getting the diaphragm on that side up higher, the chest cavity down, and the mediastinum to shift from the other side, to decompress the other side, to the contralateral side of the operation. That improves pulmonary mechanics. We have 2 patients in this group in whom we did pneumonectomies because there was very less functional lung left behind, and they did very well. So I think those are two reasons.
Your second question, I think that is something that needs to be done. I think some patients get benefit from a unilateral operation, and after it peters out, larger studies need to be done to define that.
DR DANIEL L. MILLER (Atlanta, GA): Keith, I have a question. There was a small number of unilaterals in the NETT that couldn't go—were there any at all that could not go on to the contralateral side? I couldn't remember; 5 or 6?
DR NAUNHEIM: Yes. Obviously the ones we knocked off didn't go on to have the other side operated on. Generally when it was done unilaterally, it was done because there was an intraoperative problem, and there were a few who went on to a second side, but the majority of them, as far as I remember, ended up having a unilateral one, though that was less than 10, and I don't think we have ever looked at the results specifically of those people.
DR JOHN R. ROBERTS (Nashville, TN): I want to make sure I understand. I think your abstract says that you had a perioperative mortality of 2% for the unilaterals and 4% for the bilaterals, and then did your presentation indicate a 4% operative mortality?
DR SULTAN: Yes, absolutely right. After the abstract was submitted, I went back and looked. There was 1 patient who had a complication of a perforated esophagus, and she stayed in the hospital after being repaired but never left the hospital and died 6 months later after the procedure. So initially we did not catch that, but when I went back and reviewed everything carefully, I saw that there was 1 more patient who did not leave the hospital after the operation. And this perforation did not happen anywhere in the field of where we were operating. It was a right upper lobe LVRS and the perforation was in the distal esophagus. I talked to Dr Cooper about it. He thinks that it was probably some sort of traction injury or maybe a stapler, someone got in and caught it, but we were not sure.
DR ROBERTS: So then your operative mortality is equivalent between the two procedures?
DR SULTAN: Yes, 4%.
DR ROBERTS: And at the end of your abstract you state that you still prefer bilateral LVRS, yet your survival was the same, and it looked as though your perioperative complications were equivalent, perhaps even less for the unilateral, as I understand your presentation. What is your rationale for preferring bilateral LVRS?
DR SULTAN: Bilateral LVRS is still our preferred approach, because when we compared all the pulmonary function tests and the 6-minute walk, the patient with the bilateral operation walked better after operation, and the SF-36 functional score of the bilateral group was 55 in 6 months compared with the unilateral group, which was 33, and also the survival in the long run, bilateral survival was 68% from our 250 patients compared with 55%.
DR JOSEPH B. SHRAGER (Philadelphia, PA): Can you theorize why you get fully a 20% reduction in your residual volume when you are only doing one side? I mean you don't typically get a 40% reduction when you do both sides, and you showed on one of your curves that the residual volumes are similar in the amount that they fall. Also, you mentioned that you do an 80% right upper lobe resection, which is a very large portion of one lobe to remove with a wedge. You are leaving a little nubbin, really, of the right upper lobe. Are you being more aggressive with the size of your resection when you know you're only doing one side as opposed to doing both?
DR SULTAN: I think that is the case. Our operative strategy has evolved. As you know, initially we did U-shaped LVRS and now we do as much as possible. We take off 80% of the right upper lobe, or on the left side 60%, sparing the lingula. The residual volume, if you ask me what is the physiologic explanation behind that, I won't be able to tell you why exactly we are seeing that much reduction in residual volume.
DR HANI SHENNIB (Montreal, Quebec, Canada): That was a very nice paper. My question has to do with the survival curve that you have shown. In your opinion and in your analysis, do you find that the attrition of survival is similar to what would be reported for COPD patients, end-stage, with a similar subset of characters, or do you think that this operation would have an attrition rate that is better or worse than the same group of patients if you look at their survival in 5 years?
DR SULTAN: We reported this data in our Medicare patients who were refused operations, and those are all bilateral patients in our institution. We have seen that an LVRS operation usually is better than that group of patients who did not receive the operation because Medicare refused to pay for those operations.
DR SHENNIB: So in light of the unilateral results that you are showing right now, can you extrapolate on that?
DR SULTAN: I think the unilateral has a survival benefit. I mean we have not compared that to the natural history of the emphysema patient. I mean I can't tell point to point what the survival difference is.
DR SHENNIB: And as a philosophy today, would you consider unilateral a better option for patients who potentially will have a lung transplant?
DR SULTAN: This was a group of higher-risk patients. They were older patients. They were like 4 years older than our bilateral group. They had relative cardiac comorbidities, which we thought at that time made it a higher risk for operation. For that group of patients, I think the unilateral approach would be very good to see. I was talking to Dr Cooper and he said that when he was thinking about these operations, he was seeing how this patient gets through the operation and then maybe do a second side. But none of these 49 patients got a second operation. We still prefer the bilateral approach, but for a selected group of patients I think unilateral is a safe operation and gives them good functional benefit.
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