HHE Respiratory 2019 - Page 5

Endobronchial coil implantation The coil procedure (PneumRx Inc, Mountain View, CA, USA) was developed for patients with heterogeneous and homogenous emphysema with interlobar collateral ventilation. The procedure is performed under general anaesthesia and fluoroscopy. Approximately 8 and 14 nitinol coils (average of 10) are placed in the targeted lobe using bronchoscopy. The length of the airway is measured by the guide wire during the procedure, and 100, 125, and 150mm coils are used in the procedure. Using the carrier catheter, the coil is advanced to the targeted bronchus, but it is recommended not to place it too close to the central vascular structures and pleura. 12 By pulling the catheter, the coil returns to its original shape before it is loaded into the catheter, thus reducing lung volume. The same procedure is applied in the other lung within four to eight weeks. Following the procedure, patients are kept under observation for one to two days. In order to obtain a good response, the patient must have healthy parenchymal tissue in the non-targeted lung areas. 6–8 severe emphysema. Values of patient forced expiratory volume in 1 second (FEV1) should be between 15% and 50% (15–45% for coil), and findings indicating the presence of hyperinflation (TLC >100%, RV >175%, RV/TLC ≥0.58) are required. Although there is no clear evidence, it is recommended by experts that these therapies should be avoided in patients with hypercapnia (PCO2 >55–60mmHg) and pulmonary hypertension (PAB > 50mmHg). 7 Patient results for the 6-minute walk test (6MWT) should be in the range of 150–450m. Furthermore, these expensive treatments are not recommended for active smokers. To be considered for ELVR treatment, patients should have quit smoking at least two months prior; cessation of smoking six months before is most ideal (Table 1). Contraindications These treatments are not recommended for patients with clinically relevant bronchiectasis, lung cancer, bullous lesions greater than 4cm, history of prior lung surgery, severe hypoxia (PaO2 <45mmHg), hypercapnia (PCO2 >55–60), or in patients undergoing anticoagulation therapy. 7 In addition, these treatments are not recommended in patients with impaired general status or in those who have comorbidities that might significantly affect survival. Other contraindications include unstable cardiovascular disease such as unstable arrhythmia, severe heart failure (left ventricular ejection fraction <35%), and stroke or myocardial infarction within the last six months. 8 Although genetic α-1 antitrypsin deficiency has been accepted as a criterion for exclusion, discussion continues as to whether it should be considered as a contraindication. Procedure The most frequently used and most evidence- based ELVR methods are the valve and coil procedures. Although their mechanisms of action are different, these methods can be performed in patients with both heterogeneous and homogenous emphysema. The treatment algorithm for these methods is shown in Figure 1. 1,9 The valves are fully reversible, and coils are partially reversible, but it is not possible to recycle all applied coils. 10 The most important reason for increasing treatment efficacy is correct patient and appropriate treatment method selection Endobronchial valve implantation The evaluation of collateral ventilation and the fissure completeness score (FCS) is very important prior to treatment. These evaluations are performed by qualitative computed tomography and via the Chartis system during bronchoscopy. If the FCS and collateral flow are above 95%, valve therapy can be applied directly. Measurement with the Chartis system is required when collateral flow is between 80% and 95%. However, alternative endoscopic methods and surgeries should be considered in patients with collateral flow scores below 80%. 7 Under light sedation, endobronchial valves are placed into bronchoscopically targeted segmental bronchi. Atelectasis and volume-reducing effects are achieved after blocking the hyperinflated lung lobe. Targeted lobar volume reduction is the efficacy outcomes measure, which is considered to be positive when a reduction of 350ml is achieved. 11 Benefits In the studies conducted to date, EBV treatment resulted in an average increase in FEV1 values of 77.5ml (34.5–140.0ml), an increase in results of the 6MWT of 40.8m (9.3–91.0m), and an average decrease in RV values of 440ml (200–680ml). 6 In addition, the following were observed: increased patient quality of life, a St George’s Respiratory Questionnaire (SGRQ) score decrease of 7.0 points, a modified Medical Research Council (mMRC) score decrease of 0.8 points, a BODE Index decrease of 1.2 points, and increased exercise tolerance. 7 In a review of the coil procedure, it was reported that coil treatment resulted in an average increase in FEV1 values of 130ml (90–200ml), an increase in results for the 6MWT of 47.0m (14.6–84.0m), and an average decrease in RV values of 420ml (310–510ml). 6 A significant increase in patient quality of life was also observed (SGRQ –12 points). 7 Additionally, improvements in scores of anxiety and depression were recorded in this patient group. 13 In a recent study, coil treatments were reported to cause improvements in blood gas parameters in patients with hypoxic or mild hypercapnic respiratory failure. 14 Potential complications Although ELVR therapies are minimally invasive procedures, they can lead to various complications due to the presence of COPD with severe emphysema. Pneumothorax (17.3%), valve migration (2.1%), pneumonia (1.7%), haemoptysis (1.9%), respiratory failure (1.4%), and exacerbations of COPD (0.9%) were reported in a recent study after application of EBV procedures. 15 Pneumothoraces (86%) usually occur within the first 72 hours, indicating that patients should be hospitalised immediately for a minimum of 72 hours following the procedure. 16 COPD exacerbation (41.0%) is the most frequent complication of coil procedures, followed by pneumonia (14.8%), and pneumothorax (5.7%). 6 These complications may occur either immediately after the procedure or during 5 HHE 2019 | hospitalhealthcare.com