Outcome After Lung Volume Reduction Surgery in Patients With Severely Impaired Diffusion Capacity

Surgical and bronchoscopic pulmonary function-improving procedures in lung emphysema

COPD is a highly prevalent, chronic and irreversible obstructive airway disease without curative treatment. Standard therapeutic strategies, both non-pharmacological and pharmacological, have only limited effects on lung function parameters of patients with severe disease. Despite optimal pharmacological treatment, many patients with severe COPD still have a high burden of dyspnoea and a poor quality of life. If these patients have severe lung emphysema, with hyperinflation as the driver of symptoms and exercise intolerance, lung volume reduction may be an effective treatment with a significant impact on lung function, exercise capacity and quality of life. Currently, different lung volume reduction approaches, both surgical and bronchoscopic, have shown encouraging results and have been implemented in COPD treatment recommendations. Nevertheless, choosing the optimal lung volume reduction strategy for an individual patient remains challenging. Moreover, there is still room for improving durability of effect and safety in all available procedures. Ongoing and innovative research is essential to push this field forwards. This review provides an overview of results and limitations of the current lung volume reduction options for patients with severe lung emphysema and hyperinflation.

Relevance of pleural adhesions for short- and long-term outcomes after lung volume reduction surgery

Objective

Pleural adhesions (PLAs) have been shown to be a possible risk factor for air leak after lung volume reduction surgery (LVRS), but the relevance of PLA for lung function outcome remains unclear. We analyzed our LVRS cohort for the influence of PLA on short-term (ie, prolonged air leak) and long-term outcomes.

Methods

Retrospective observational cohort study with 187 consecutive patients who underwent LVRS from January 2016 to December 2019. PLA were defined as relevant if they were distributed extensively at the dorsal pleura; were present in at least at 2 areas, including the dorsal pleura; or present extensively at the mediastinal pleura. In patients with bilateral emphysema, bilateral LVRS was performed preferentially. The objectives were to quantify the association of PLA and rate of prolonged air leak (chest tube >7 days), and the association of PLA with postoperative exacerbations and with forced expiratory volume in 1 second 3 months postoperatively. The associations were quantified with odds ratios for binary outcomes, and with between-group differences for continuous outcomes. To account for missing observations, 100-fold multiple imputation was used.

Results

PLAs were found in 46 of 187 patients (24.6%). There was a 32.6% rate of prolonged air leak (n = 61), mean chest tube time was 7.84 days. A total of 94 (50.3%) LVRSs were unilateral and 93 were bilateral. There was evidence for an association between PLA and the rate of prolonged air leak (odds ratio, 2.83; 95% CI, 1.36 to 5.89; P = .006). There was no evidence for an association between PLA and postoperative exacerbations (odds ratio, 1.11; 95% CI, 0.5 to 2.45; P = .79). There was no evidence for an association between PLA and forced expiratory volume in 1 second (estimate -1.52; 95% CI -5.67 to 2.63; P = .47). Both unilateral and bilateral LVRS showed significant postoperative improvements in forced expiratory volume in 1 second by 27% (8.43 units; 95% CI, 3.66-13.12; P = .0006) and by 28% (7.87 units; 95% CI, 4.68-11.06; P < .0001) and a reduction in residual volume of 15% (-33.9 units; 95% CI, -56.37 to -11.42; P = .003) and 15% (-34.9 units; 95% CI, -52.57 to -17.22; P = .0001), respectively.

Conclusions

Patients should be aware of potential prolongation of hospitalization due to PLA. However, there might be no relevant influence of PLA on lung function outcomes.

[Surgical or bronchoscopic lung volume reduction for emphysema therapy]

More than 20 years ago, surgical lung volume reduction (LVRS) was already established in patients with advanced emphysema as a palliative therapy option that reduces respiratory distress and improves lung function and quality of life. In addition, bronchoscopic procedures (BLVR) aimed at volume reduction have existed for just over 10 years. The advantages and disadvantages of LVRS and BLVR are discussed in this article.

Lung volume reduction surgery as salvage procedure after previous use of endobronchial valves

OBJECTIVES

Lung volume reduction (LVR) is an efficient and approved treatment for selected emphysema patients. There is some evidence that repeated LVR surgery (LVRS) might be beneficial, but there are no current data on LVRS after unsuccessful bronchoscopic LVR (BLVR) with endobronchial valves (EBVs). We hypothesize good outcome of LVRS after BLVR with valves.

METHODS

In this study, we retrospectively investigated all patients who underwent LVRS between 2015 and 2019 at 2 centres after previous unsuccessful EBV treatment. They were further divided into subgroups with patients who never achieved the intended improvement after BLVR (primary failure) and patients whose benefit was fading over time due to the natural development of emphysema (secondary failure). Patients with severe air leak after BLVR and immediate concomitant LVRS and fistula closure thereafter were analysed separately.

RESULTS

A total of 38 patients were included. Of these, 19 patients had primary failure, 15 secondary failure and 4 were treated as an emergency due to severe air leak. At 3 months after LVRS, forced expiratory volume in 1 s had improved significantly by 12.5% (P = 0.011) and there was no 90-day mortality. Considering subgroups, patients with primary failure after BLVR seem to profit more than those with secondary failure. Patients with severe air leak after BLVR did not profit from fistula closure with concomitant LVRS.

CONCLUSIONS

LVRS after previous BLVR with EBVs can provide significant clinical improvement with low morbidity, although results might not be as good as after primary LVRS.

Lung Volume Reduction Surgery in Patients with Homogeneous Emphysema

Randomized controlled trials have demonstrated that lung volume reduction surgery (LVRS) improves exercise capacity, lung function, and quality of life in patients with heterogenous emphysema on computed tomographic and perfusion scan. However, most patients have a nonheterogenous type of destruction. These patients, summarized under "homogeneous emphysema," may also benefit from LVRS as long they are severely hyperinflated, and adequate function is remaining with a diffusing capacity of the lungs for carbon monoxide greater than 20% and no pulmonary hypertension. Surgical mortality is low when patients are well selected.

Endoscopic lung volume reduction with endobronchial valves in very low D LCO patients: results from the German Registry - Lungenemphysemregister e.V

Background

Endoscopic lung volume reduction (ELVR) with valves has been suggested to be the key strategy for patients with severe emphysema and concomitant low diffusing capacity of the lung for carbon monoxide (D_LCO). However, robust evidence is still missing. We therefore aim to compare clinical outcomes in relation to D_LCO for patients treated with ELVR.

Methods

We assessed D_LCO at baseline and 3 months follow-up and compared pre- and postprocedural pulmonary function test, quality of life, exercise capacity and adverse events. This is a retrospective subanalysis of prospectively collected data from the German Lung Emphysema Registry.

Results

In total, 121 patients treated with ELVR were analysed. Thirty-four patients with a D_LCO ≤20% and 87 patients with a D_LCO >20% showed similar baseline characteristics. After ELVR, there was a decrease of residual volume (both p<0.001 to baseline) in both groups, and both demonstrated better quality of life (p<0.01 to baseline). Forced expiratory volume in 1 s (FEV₁) improved significantly only in patients with a D_LCO >20% (p<0.001 to baseline). Exercise capacity remained almost unchanged in both groups (p=0.3). The most frequent complication for both groups was a pneumothorax (D_LCO ≤20%: 17.6% versus D_LCO >20%: 16.1%; p=0.728). However, there were no significant differences in other adverse events between both groups.

Conclusions

ELVR improves lung function as well as quality of life in patients with D_LCO >20% and D_LCO ≤20%. Adverse events did not differ between groups. Therefore, ELVR should be considered as a treatment option, even in patients with a very low D_LCO.

Endoscopic lung volume reduction with endobronchial valves can be safely performed in patients with a very low diffusing capacity of the lung (D_LCO). Clinical effectiveness is comparable to patients with higher D_LCO.https://bit.ly/3cOgDK1

Lung volume reduction surgery: from National Emphysema Treatment Trial to non-intubated awake video-assisted thoracoscopic surgery

Chronic obstructive pulmonary disease (COPD) is a major public health problem. Loss of elastic recoil, hyperinflation and obstruction of the expiratory airflow lead to an increased breathing work, which results in dyspnea during minimal physical activity of the patients. Reduction of the lung volume in these patients leads to improvement of dyspnea, physical activity and quality of life in these patients. Beside endoscopic lung volume reduction (ELVR), lung volume reduction surgery (LVRS) represents an important and valuable treatment option for patients with advanced lung emphysema. Since the National Emphysema Treatment Trial (NETT), thoracic surgery experienced a remarkable evolution of the surgical techniques enabling safe surgery and quick recovery in this critically ill patient cohort. A paradigm shift from open surgical approaches to most minimally invasive techniques accompanied by improvement of anesthesiologic management of these patients was evident. Moreover, indications for LVRS, which were originally described in the NETT, were extended to apply for further groups of patients with advanced lung emphysema, enabling significant clinical improvement in well-selected patients with a low perioperative morbidity and mortality. The current review will give an overview of the historical approaches for LVRS, highlight the indications for LVRS and discuss the development of the surgical approaches.

The effects of lung volume reduction treatment on diffusing capacity and gas exchange

Lung volume reduction (LVR) treatment in patients with severe emphysema has been shown to have a positive effect on hyperinflation, expiratory flow, exercise capacity and quality of life. However, the effects on diffusing capacity of the lungs and gas exchange are less clear. In this review, the possible mechanisms by which LVR treatment can affect diffusing capacity of the lung for carbon monoxide (D _LCO) and arterial gas parameters are discussed, the use of D _LCO in LVR treatment is evaluated and other diagnostic techniques reflecting diffusing capacity and regional ventilation (V')/perfusion (Q') mismatch are considered.A systematic review of the literature was performed for studies reporting on D _LCO and arterial blood gas parameters before and after LVR surgery or endoscopic LVR with endobronchial valves (EBV). D _LCO after these LVR treatments improved (40 studies, n=1855) and the mean absolute change from baseline in % predicted D _LCO was +5.7% (range -4.6% to +29%), with no real change in blood gas parameters. Improvement in V' inhomogeneity and V'/Q' mismatch are plausible explanations for the improvement in D _LCO after LVR treatment.

Consolidating Lung Volume Reduction Surgery After Endoscopic Lung Volume Reduction Failure

BACKGROUND

Bronchoscopic valve placement constitutes an effective endoscopic lung volume reduction (ELVR) therapy in patients with severe emphysema and low collateral ventilation. After the most destroyed lobe is occluded with valves, significant target lobe volume reduction leads to improvements in lung function, exercise capacity, and quality of life. The effects are not consistent in some patients, leading to long-term therapy failure. We hypothesized that surgical lung volume reduction (LVRS) would reestablish ELVR short-term clinical improvements after ELVR long-term failure.

METHODS

This retrospective single-center analysis included all patients who underwent consolidating LVRS by lobectomy after long-term failure of valve therapy between 2010 and 2015. Changes in forced expiratory volume in 1 second, residual volume, 6-minute walking distance, and Modified Medical Research Council dyspnea score 90 days after ELVR and LVRS were analyzed, and the outcomes of both procedures were compared.

RESULTS

LVRS was performed in 20 patients after ELVR failure. A lower lobectomy was performed in 90%. The 30-day mortality of the cohort was 0% and 90-day mortality was 5% (1 of 20). The remaining 19 patients showed a significant increase in forced expiratory volume in 1 second (+27.5% ± 19.4%) and a reduction in residual volume (-21.0% ± 17.4%) and total lung capacity (-11.1% ± 11.1%). This resulted in significant improvements in exercise tolerance (6-minute walking distance: +56 ± 60 m) and relief of dyspnea (ΔModified Medical Research Council: -1.8 ± 1.4 points.).

CONCLUSIONS

Consolidating LVRS by lobectomy after failure of a previously successful ELVR is feasible and results in significant symptom relief and improvement of lung function.

Identification of target zones for lung volume reduction surgery using three-dimensional computed tomography rendering

Background

The key issues for performing lung volume reduction surgery (LVRS) is the identification of the target zones. Recently introduced three-dimensional computed tomography rendering methods are used to identify the morphological distribution and its severity of lung emphysema by densitometry. We demonstrate a new software for emphysema imaging and show the pre- and post-operative results in patients undergoing LVRS planned based on this new technology.

Methods

A real-time three-dimensional image analysis software system was used pre- and 3 months post-operatively in five patients with heterogeneous emphysema and a single patient with homogeneous morphology scheduled for LVRS. Focus was on low attenuation areas with <950 HU, distribution on both lungs and the value of the three-dimensional images for planning surgery. Functional outcome was assessed by pulmonary function tests after 3 months.

Results

Five patients underwent bilateral LVRS and one patient had unilateral LVRS. All patients showed a median increase in forced expiratory volume in 1 s of 70% (range 30–120%), compared with baseline values. Hyperinflation (expressed as residual volume/total lung capacity ratio) was reduced by 30% (range 5–32%). In the patients with heterogeneous emphysema, the pre- and post-operative computed tomography scans and the densitometries showed a decrease in low attenuation areas by 23% (right side) and by 17% (left side), respectively.

Conclusion

We demonstrate three-dimensional computed tomography-rendered images for planning personalised remodelling of hyperinflated lungs using LVRS. This user-friendly software has the potential to assist surgeons and interventional pulmonologists to select patients and to visualise target areas in LVRS procedures.

New, user-friendly software with 3D CT-rendered images can be used for planning personalised remodelling of hyperinflated lungs using LVRShttps://bit.ly/3fbICn2

Endobronchial Valve Treatment in Emphysema Patients with a Very Low DLCO

BACKGROUND

For selected patients with severe emphysema, bronchoscopic lung volume reduction with endobronchial valves (EBV) is recognized as an additional treatment option. In most trials investigating EBV treatment, patients with a very low diffusing capacity (DLCO) were excluded from participation.

OBJECTIVES

Our goal was to investigate whether EBV treatment in patients with emphysema with a very low DLCO is safe and effective.

METHODS

This was a single-center retrospective analysis including patients with emphysema and a DLCO ≤20%pred who underwent EBV treatment. Follow-up was performed 6 months post-treatment. Outcome parameters were compared to a historical matched control group (DLCO >20%pred, matched for sex, age, forced expiratory volume in 1 s [FEV1], and residual volume [RV]).

RESULTS

Twenty patients (80% female, 64 ± 6 years, FEV1 26 ± 6%pred, RV 233 ± 45%pred, DLCO 18 ± 1.6%pred) underwent EBV treatment. At 6 months follow-up, we found a statistically significant improvement in FEV1 (0.08 ± 0.12 L), RV (-0.45 ± 0.95 L), 6-min walking distance (38 ± 65 m), and St. George's Respiratory Questionnaire (-12 ± 13 points). With the exception of FEV1, all exceeded the minimal clinically important difference. The most common serious adverse event was a pneumothorax requiring intervention (15%). There were no significant differences in outcome compared to the DLCO >20%pred control group.

CONCLUSIONS

In this single-center retrospective analysis, we showed statistically significant and clinically relevant improvements in lung function, exercise capacity, and quality of life up to 6 months after EBV treatment in emphysema patients with a DLCO ≤20% (14-20%) of predicted with no increased risk of serious adverse events.

Surgical and endoscopic interventions that reduce lung volume for emphysema: a systemic review and meta-analysis

BACKGROUND

Severe emphysema is a debilitating condition with few treatment options. Lung volume reduction procedures in the treatment of severe emphysema have shown excellent results in selected patients but their exact role remains unclear with studies reporting a wide variation in outcomes. We therefore aimed to evaluate the effects of volume reduction.

METHODS

We did a systematic review and meta-analysis. We searched MEDLINE on Sept 29, 2016, for trials of lung volume reduction in patients with emphysema, and we did an updated search on Embase and PubMed on June 18, 2018. We only included randomised controlled studies published in English evaluating the intervention with either sham or standard of care. Inclusion was limited to trials of techniques in which there was sustainable volume reduction. Primary outcomes were residual volume, FEV₁, St George's Respiratory Questionnaire (SGRQ), and 6-min walk distance (6MWT). Secondary outcomes were severe adverse events (including mortality), short-term mortality, and overall mortality. We extracted summary level data from the trial publications and where necessary we obtained unpublished data. A random-effects model with the I² statistic was used to determine heterogeneity and trial weight in each analysis. The study is registered with the PROSPERO database, number CRD42016045705.

FINDINGS

We identified 4747 references in the search, and included 20 randomised controlled trials of lung volume reduction involving 2794 participants with emphysema. Following lung volume reduction from any of the interventions in pooled analyses (ie, surgery, endobronchial valve, endobronchial coil, or sclerosing agents), the mean differences compared with the control were reduction in residual volume of 0·58 L (95% CI -0·80 to -0·37), increase in FEV₁ of 15·87% (95% CI 12·27 to 19·47), improvement in 6MWT of 43·28 m (31·36 to 55·21), and reduction in the SGRQ of 9·39 points (-10·92 to -7·86). The odds ratio for a severe adverse event, which included mortality, was 6·21 (95% CI 4·02 to 9·58) following intervention. Regression analysis showed improvements relative to the degree of volume reduction: FEV₁ (r²=0·86; p<0·0001), 6MWT (r²=0·77; p<0·0001), and SGRQ (r²=0·70; p<0·0001). Most studies were at high risk of bias for lack of blinding, and heterogeneity was high for some outcomes when pooled across all interventions, but was generally lower in the subgroups by intervention type.

INTERPRETATION

Despite limitations of high risk of bias and heterogeneity for some analyses, our results provide support that lung volume reduction in patients with severe emphysema on maximal medical treatment has clinically meaningful benefits. These benefits should be considered alongside potential adverse events.

FUNDING

None.

Lung volume reduction surgery beyond the NETT selection criteria

Lung volume reduction surgery (LVRS) for symptomatic patients with advanced emphysema was proven to be successful in a large randomized multi-center trial (NETT) and in several smaller randomized single center trials. This evidence primarily concerns patients with heterogeneous, upper-lobe predominant emphysema and low exercise tolerance within certain selection criteria regarding lung function values. As the most important effect of LVRS is generated by reducing the hyperinflation, even patients with homogeneous emphysema morphology profit from the procedure. Simultaneously, by removing distended and functionless areas in heterogeneous emphysema, also patients with seriously impaired diffusion capacity, moderate pulmonary arterial hypertension, a history of previous LVRS and alpha-1-antitrypsin-deficiency (AATD) can be considered as candidates for (re-)-LVRS. This article summarizes indications for LVRS in these various subtypes of emphysema patients.

Pulmonary hypertension in chronic obstructive pulmonary disease and emphysema patients: prevalence, therapeutic options and pulmonary circulatory effects of lung volume reduction surgery

The exact prevalence of pulmonary hypertension (PH) and cor pulmonale (CP) in chronic obstructive pulmonary disease (COPD) is unknown, and varies considerably from 20-91%. Usually, mean pulmonary artery pressure (mPAP) does not exceed 30 mmHg, and PH is not severe. However, PH and CP are important predictors of mortality in COPD and contribute to disability in this disease. Many factors contribute to the development of PH in chronic lung disease, including reduction of the pulmonary vascular cross-sectional area due to parenchymal loss and accompanying hypoxia, effects of abnormal pulmonary mechanics due to hyperinflation, but also vascular remodeling processes. So far, PH associated with chronic lung disease cannot be treated medically. Therefore, it is indicated to treat the underlying pulmonary disease. Patients with severe PH should be referred to centers experienced in the management of PH and enrollment in clinical trials should be considered. Lung volume reduction surgery (LVRS) theoretically further increases pulmonary vascular resistance (PVR) by reducing the vascular bed when resecting lung tissue, however, this might be compensated by better pulmonary mechanics through reduction of hyperinflation, which will be discussed in the present article.