Safety of Transbronchial Biopsies in Patients with Pulmonary Hypertension: Systematic Review and Meta-Analysis.

Rationale: Transbronchial lung biopsies (TBLBs) are commonly performed by pulmonologists. Most providers consider pulmonary hypertension to be at least a relative contraindication to TBLB. This practice is based primarily on expert opinion, as there are very few patient outcomes data backing it. Objectives: We performed a systematic review and meta-analysis of previously published studies to determine the safety of TBLB in patients with pulmonary hypertension. Methods: The MEDLINE, Embase, Scopus, and Google Scholar databases were searched for pertinent studies. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. Meta-analysis was performed using MedCalc version 20.118 to calculate the weighted pooled relative risk of complications in patients with pulmonary hypertension. Results: Nine studies with a total of 1,699 patients were included in the meta-analysis. On the basis of the Newcastle-Ottawa Scale, the risk of bias was low in the included studies. The overall weighted relative risk of bleeding with TBLB in patients with pulmonary hypertension was 1.01 (95% confidence interval, 0.71-1.45) compared with patients without pulmonary hypertension. Heterogeneity was low; therefore, the fixed-effects model was used. In a subgroup analysis of three studies, the overall weighted relative risk of significant hypoxia in patients with pulmonary hypertension was 2.06 (95% confidence interval, 1.12-3.76). Conclusions: Our results show that the patients with pulmonary hypertension do not have a significantly elevated risk of bleeding with TBLB compared with control subjects. We hypothesize that significant postbiopsy bleeding might be preferentially originating from bronchial artery circulation as opposed to pulmonary artery circulation, much like episodes of massive spontaneous hemoptysis. This hypothesis can explain our results, as in this scenario, elevated pulmonary arterial pressure would not be expected to have a bearing on the risk of post-TBLB bleeding. Most of the studies in our analysis included patients with mild to moderate pulmonary hypertension and it is not clear if our results can be extrapolated to patients with severe pulmonary hypertension. We noted that the patients with pulmonary hypertension were at a higher risk of developing hypoxia and needing a longer duration of mechanical ventilation with TBLB compared with control subjects. Further studies are needed to better understand the origin and pathophysiology of post-TBLB bleeding.

Diagnostic Performance and Safety Profile of Robotic-assisted Bronchoscopy: A Systematic Review and Meta-Analysis.

Rationale: Conventional electromagnetic navigation bronchoscopy and other guided bronchoscopic modalities have a very desirable safety profile, but their diagnostic yield is only 60-70% for pulmonary lesions. Recently, robotic-assisted bronchoscopy (RAB) platforms have been introduced to improve the diagnostic performance of bronchoscopic modalities. Objectives: To determine the diagnostic performance and safety profile of RAB (using shape-sensing and electromagnetic navigation-based platforms) by performing a systematic review and meta-analysis. Methods: The PubMed, Embase, and Google Scholar databases were searched to find studies that reported on the diagnostic performance and/or the safety profile of one of the RAB systems. The quality of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Meta-analysis was performed using MedCalc version 20.118. Pooled diagnostic yield was calculated using a Freeman-Tukey transformation. We planned to use a random-effects model if the I2 index was >40%. Results: Twenty-five studies were included: 20 including diagnostic and safety analyses and 5 including only safety analyses. The pooled diagnostic yield of RAB (20 studies, 1,779 lesions) was 84.3% (95% confidence interval, 81.1-87.2%). The I2 index was 65.6%. On the basis of our subgroup analyses, the heterogeneity was likely driven by differences in study designs (prospective vs. retrospective) and procedural protocols (such as different RAB systems). Lesion size > 2 cm, the presence of a computed tomography bronchus sign, and concentric radial endobronchial ultrasound view were associated with a statistically significant increase in the odds of diagnosis with RAB. The overall rates of pneumothorax, need for tube thoracostomy, and significant hemorrhage were 2.3%, 1.2%, and 0.5%, respectively. Conclusions: RAB systems have significantly increased the diagnostic yield of navigational bronchoscopy compared with conventional systems such as electromagnetic navigation bronchoscopy, but well-designed prospective studies are needed to better understand the impact of various factors, such as the use of three-dimensional imaging modalities, cryobiopsy, and specific ventilatory protocols, on the diagnostic yield of RAB.

Orphan Lung Diseases.

There are hundreds of rare orphan lung diseases. We have highlighted five of them, one from each of the five major categories of pulmonary disorders: pleuroparenchymal fibroelastosis (a rare diffuse parenchymal lung disease), pulmonary alveolar proteinosis (a rare autoimmune and diffuse parenchymal lung disease), lymphangioleiomyomatosis (a rare cystic lung disease), yellow nail syndrome (a rare pleural disease), and Mounier-Kuhn syndrome (a rare airway disorder). The pathogenesis, clinical presentation, diagnostic criteria, treatment options, and prognosis of each disorder is discussed. This review is by no means exhaustive and further research is needed to improve our understanding of these disorders.