620	L. M. Seijo Maceiras

sedation or general anesthesia. Most procedures last less than 1 h and may target one or both lungs. Patients may undergo pulmonary rehabilitation prior to treatment, and must be on standard medical therapy for chronic obstructive pulmonary disease (COPD), including bronchodilators and occasionally low dose steroids. In general, patients with frequent exacerbations are excluded as they may be at greater risk of complications following device implantation. Endoscopic lung volume reduction has also been postulated as a bridge to lung transplantation.

Historical Perspective

Pioneers of ELVR focused on obtaining improvements in lung function and seeking measurable lung volume reduction, essentially attempting to reproduce surgical results [7]. However, the paradigm has shifted back and forth as failure to obtain comparable lung volume reduction despite improvements in quality of life made many investigators weary of attempting to match surgical outcomes. Also, while ELVR was initially reserved for ideal surgical candidates with upper lobe predominant emphysema, subsequent studies have included patients with homogeneous emphysema as well as patients with heterogeneous emphysema not necessarily upper lobe predominant. Endoscopic lung volume reduction may also be an alternative for selected patients who are not candidates for lung volume reduction surgery because of their extremely poor lung function.

The role of computed tomography (CT) has also widened. It was originally limited to patient selection, but has become a useful tool for fol- low-­up since it can quantify regional lung volume changes in the absence of overall lung volume reduction. Collateral ventilation, a major limitation of many ELVR approaches, has also been studied with CT [8]. A multicenter European study demonstrated that fssure analysis by CT correlates well with endoscopic collateral ventilation measurements [9]. If fssure integrity on

CT analysis is >95%, collateral ventilation can be considered negligible [10]. Such analysis may improve patient selection for a given procedure since valve treatment success is highly dependent on the absence of collateral ventilation while other methods of ELVR are not.

Indications and Contraindications

Endoscopic lung volume reduction is indicated for a highly selected group of patients with advanced emphysema. Originally, ELVR was reserved for patients with upper lobe predominant disease (Fig. 35.1). However, indications for ELVR have widened to include a more diverse population of patients suffering from emphysema in response to the ongoing proliferation in techniques and devices, including patients with homogeneous emphysema, alpha-1 antitrypsin defciency, or lower lobe predominant disease.

Fig. 35.1  CT reconstruction of a patient with upper lobe predominant emphysema. (Diseased lung is represented in blue). This patient with an forced expiratory volume in 1 second (FEV1) of 0.73 L (24% of predicted) was a candidate for endoscopic lung volume reduction, but a hereditary cardiomyopathy, frequent exacerbations, and pulmonary hypertension were considered contraindications to the procedure

Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/

35  Endoscopic Methods for Lung Volume Reduction	621

In general, candidates for ELVR must suffer from severe emphysema and moderate-to-severe dyspnea despite optimal medical therapy. Patients with alpha-1 antitrypsin defciency have been historically excluded from clinical trials, although limited evidence from recent trials investigating the role of ELVR for those patients and at least one small series showed signifcant beneft from ELVR in that setting [11, 12].

Ideal candidates for ELVR must be ambulatory and capable of walking at least 100–150 m with or without supplemental oxygen during a 6 min walk test. They must abstain from smoking and demonstrate severe obstruction on spirometry as well as air trapping and hyperin ation on plethysmography. ELVR should probably not be attempted in patients with residual volumes <175% of predicted. Patients with extremely low diffusing capacities (<20%), as well as those with severe gas exchange abnormalities, especially hypercapnic patients, and frequent exacerbations are not considered good candidates for ELVR. However, a recent retrospective analysis of data collected from the German Lung Emphysema Registry showed no difference in outcomes in individuals with very low diffusing capacity for carbon monoxide (DLCO) (<20%) treated with ELVR. The technique improved lung function and quality of life in those patients, while adverse effects were similar to those seen in patients with higher DLCOs [13].

Giant bullous or reactive airways disease and severe pulmonary hypertension are also considered important contraindications to ELVR, especially coil placement, while major medical comorbidities may be an issue for some individuals. Patients with coexisting bronchiectasis, especially those colonized by P. aeruginosa, should not be treated, while patients with FEV1s less than 20–25% of the age-adjusted predicted value are generally not treated. That notwithstanding, at least one retrospective analysis has found ELVR to be feasible and safe in individuals with extremely low FEV1s improving lung function at the expense of a 25% risk of pneumothorax [14].

Elderly patients have generally been excluded from clinical trials, so outcomes of ELVR in patients older than 75 are uncertain. Most procedures are performed under general anesthesia or deep sedation, so patients unable to tolerate either cannot be treated. One should keep in mind that each device or technique designed to achieve ELVR is unique, so indications, patient selection, and/or treatment strategy (i.e., unilateral vs. bilateral treatment) may vary or are liable to change based on incoming evidence.

Description of the Equipment

Needed

ELVR can be performed in a variety of hospital settings. Many procedures are performed in the bronchoscopy suite and do not require special equipment beyond that which can generally be found in a well-stocked unit. A diagnostic or therapeutic exible bronchoscope may be used, depending on the method chosen. Devices tend to require the larger 2.8 mm channel of the therapeutic bronchoscope. Vapor-induced ELVR requires special equipment unique to this procedure.

In general, deployment of most devices, including valves, is straightforward for an experienced bronchoscopist and requires little additional training (Fig. 35.2). However, valve removal can be quite challenging if not impossible in some cases. Coil therapy is best performed under uoroscopic guidance, a technique familiar to many bronchoscopists who perform transbronchial biopsies or stent implantation. Some bronchoscopists use the Chartis™ system in order to assess fssure integrity and collateral ventilation, but others rely on CT scan data. Finally, some bronchoscopists prefer to treat patients under general anesthesia using the rigid bronchoscope or an endotracheal tube.Anesthesia support is mandatory in such cases, while others prefer conscious sedation which may be administered by the endoscopic team.