Septimiu D. Murgu

Tracheobronchomalacia and excessive dynamic airway collapse.

Abstract:  Tracheobronchomalacia and excessive dynamic airway collapse are two separate forms of dynamic central airway obstruction that may or may not coexist. These entities are increasingly recognized as asthma and COPD imitators. The understanding of these disease processes, however, has been compromised over the years because of uncertainties regarding their definitions, pathogenesis and aetiology. To date, there is no standardized classification, diagnosis or management algorithm. In this article we comprehensively review the aetiology, morphopathology, physiology, diagnosis and treatment of these entities.

Follow-up and Surveillance of the Patient With Lung Cancer After Curative-Intent Therapy: Diagnosis and Management of Lung Cancer, 3rd ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND These guidelines are an update of the evidence-based recommendations for follow-up and surveillance of patients after curative-intent therapy for lung cancer. Particular updates pertain to whether imaging studies, health-related quality-of-life (HRQOL) measures, tumor markers, and bronchoscopy improve outcomes after curative-intent therapy. METHODS Meta-analysis of Observational Studies in Epidemiology guidelines were followed for this systematic review, including published studies on posttreatment outcomes in patients who received curative-intent therapy since the previous American College of Chest Physicians subject review. Four population, intervention, comparison, and outcome questions were formulated to guide the review. The MEDLINE and CINAHL databases were searched from June 1, 2005, to July 8, 2011, to ensure overlap with the search strategies used previously. RESULTS A total of 3,412 citations from MEDLINE and 431 from CINAHL were identified. Only 303 were relevant. Seventy-six of the 303 articles were deemed eligible on the basis of predefined inclusion criteria after full-text review, but only 34 provided data pertaining directly to the subject of the questions formulated to guide this review. In patients undergoing curative-intent surgical resection of non-small cell lung cancer, chest CT imaging performed at designated time intervals after resection is suggested for detecting recurrence. It is recommended that treating physicians who are able to incorporate the patients clinical findings into decision-making processes be included in follow-up and surveillance strategies. The use of validated HRQOL instruments at baseline and during follow-up is recommended. Biomarker testing during surveillance outside clinical trials is not suggested. Surveillance bronchoscopy is suggested for patients with early central airway squamous cell carcinoma treated by curative-intent photodynamic therapy and for patients with intraluminal bronchial carcinoid tumor who have undergone curative-intent bronchoscopic treatment with Nd:YAG laser or electrocautery. CONCLUSIONS There is a paucity of well-designed prospective studies specifically targeting follow-up and surveillance modalities aimed at improving survival or QOL after curative-intent therapy. Additional research is warranted to clarify which curative-intent treatment modalities affect HRQOL the most and to identify patients who are at the most risk for recurrence or impaired QOL after treatment. Further evidence is needed to determine how the frequency and duration of surveillance programs that include imaging studies, QOL measurements, tumor markers, or bronchoscopy affect patient morbidity, survival, HRQOL, and health-care costs.

Tracheobronchomalacia and Excessive Dynamic Airway Collapse

Tracheobronchomalacia and excessive dynamic airway collapse are morphologic types of expiratory central airway collapse with specific pathophysiology, cause, and structural changes in airway wall. Physicians caring for symptomatic patients with expiratory central airway collapse must localize the flow-limiting airway segments amenable to bronchoscopic or surgical interventions. Functional bronchoscopy and dynamic radiologic studies are performed for the initial evaluation and to design follow-up strategies. Research is needed to determine noninvasive and reliable physiologic methods for localizing the flow-limiting segments that might guide patient selection for treatment and predict response to interventions.

Treatment of Adult Tracheobronchomalacia and Excessive Dynamic Airway Collapse

Tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC) are both dynamic forms of central airway obstruction characterized by a decrease of ≥50% in the cross-sectional area of the tracheobronchial lumen. The differences between these two entities, however, are not uniformly accepted in the medical community. While TBM is characterized by a weakness of the tracheobronchial cartilaginous structures, EDAC is marked by excessive bulging of the posterior membrane into the airway lumen during exhalation. These disease entities are probably underdiagnosed because they present with a variety of nonspecific symptoms similar to patients with other obstructive ventilatory disorders such as asthma and COPD. Diagnosis is confirmed by dynamic radiologic imaging studies or bronchoscopy. Current therapeutic management depends on the extent, type, and severity of airway abnormalities noted and the clinical presentation. Proposed management alternatives include conservative medical therapy, and minimally invasive and open surgical interventions. Inhaled bronchodilators should be used only if symptoms and ventilatory function improve after use. Continuous positive airway pressure acts as a pneumatic stent and should be considered as an alternative or additional therapeutic modality. Endoluminal stent insertion can improve symptoms and pulmonary function in patients with central airway obstruction and should be considered for patients with symptoms refractory to conservative therapy. Several open surgical procedures have also been performed over the years, including tracheostomy, airway splinting, tracheal resection and, more recently, external tracheal stents. Endobronchial laser therapy, resorbable stents, application of grafting materials used to support the collapsed airway as well as the use of cartilage regeneration techniques are experimental, and their efficacy in humans remains to be determined. Future studies should compare therapeutic interventions and outcomes such as functional status, ventilatory function, and bronchoscopic and radiologic appearances in order to define the costs and benefits of individual and combined treatment modalities.

Description of a multidimensional classification system for patients with expiratory central airway collapse

Background and objective:  Patients with expiratory central airway collapse present with various symptoms, aetiologies, morphologies, extent and severity of airway collapse. The aim of this study was to delineate a multidimensional classification system and common language for evaluating patients with expiratory central airway collapse.

Endobronchial ultrasound morphology of expiratory central airway collapse.

Abstract:  Differences in central airway wall structure in patients with various forms of expiratory central airway collapse can be identified by endobronchial ultrasound using a 20 MHz radial probe. In tracheobronchomalacia due to relapsing polychondritis, the cartilage is thick and irregular while the membranous portion is normal. In malacia due to chronic inflammation after tracheotomy, the cartilage is thick and irregular and the membranous portion is also thick. In excessive dynamic airway collapse associated with COPD, on the contrary, the cartilage is normal and the posterior membrane is thin when compared to the normal airway wall structures identified in a patient with physiological dynamic airway collapse. These findings may support the hypothesis that various clinical forms of expiratory central airway collapse are not only different morphologically, physiologically and aetiologically, but also structurally.

Lung cancer-a fractal viewpoint.

Fractals are mathematical constructs that show self-similarity over a range of scales and non-integer (fractal) dimensions. Owing to these properties, fractal geometry can be used to efficiently estimate the geometrical complexity, and the irregularity of shapes and patterns observed in lung tumour growth (over space or time), whereas the use of traditional Euclidean geometry in such calculations is more challenging. The application of fractal analysis in biomedical imaging and time series has shown considerable promise for measuring processes as varied as heart and respiratory rates, neuronal cell characterization, and vascular development. Despite the advantages of fractal mathematics and numerous studies demonstrating its applicability to lung cancer research, many researchers and clinicians remain unaware of its potential. Therefore, this Review aims to introduce the fundamental basis of fractals and to illustrate how analysis of fractal dimension (FD) and associated measurements, such as lacunarity (texture) can be performed. We describe the fractal nature of the lung and explain why this organ is particularly suited to fractal analysis. Studies that have used fractal analyses to quantify changes in nuclear and chromatin FD in primary and metastatic tumour cells, and clinical imaging studies that correlated changes in the FD of tumours on CT and/or PET images with tumour growth and treatment responses are reviewed. Moreover, the potential use of these techniques in the diagnosis and therapeutic management of lung cancer are discussed.

Recent advances in optical coherence tomography for the diagnoses of lung disorders.

There have been many advances in the field of diagnostic and therapeutic pulmonary medicine in the past several years, with major progress in the field of imaging. Optical coherence tomography (OCT) is a high-resolution (micron level) imaging modality currently being advanced with the potential to image airway wall structures in real time and at higher resolution than previously possible. OCT has the potential to increase the sensitivity and specificity of biopsies, create 3D images of the airway to guide diagnostics, and may have a future role in diverse areas such as the evaluation and treatment of patients with obstructive sleep apnea, tracheal stenosis, airway remodeling and inhalation injury. OCT has recently been investigated to monitor airway compliance in chronic obstructive pulmonary disease and asthma patients as well as differentiate causes of pulmonary hypertension. In future clinical and research applications, OCT will likely be combined with other endoscopic based modalities such as ultrasound, spectroscopy, confocal, and/or photoacoustic tomography to determine functional and biomolecular properties. This article discusses the current uses of OCT, its potential applications, as it relates to specific pulmonary diseases, and the future directions for OCT.

Morphometric bronchoscopy in adults with central airway obstruction: Case illustrations and review of the literature†

The severity of airway narrowing impacts ventilatory function, quality of life, and choice of therapy for patients with central airway obstruction. The quantification of airway caliber remains a subjective estimate that depends on patient positioning, technique, and operator experience. In this article, we describe how morphometric bronchoscopy, a software processing method whereby bronchoscopic digital images are analyzed in order to measure airway lumen diameter, can be used to objectively quantify the degree of airway narrowing in adult patients with central airway obstruction. Laryngoscope, 2009

Diagnosing and Staging Lung Cancer Involving the Mediastinum

The purpose of this article is to provide an update on evidence-based methods for mediastinal staging in patients with lung cancer. This is a review of the recently published studies and a summary of relevant guidelines addressing the role of CT scan, PET scan, endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA), and mediastinoscopy as pertinent to lung cancer staging and restaging. The focus is on how these diagnostic methods fit into the best algorithm for patients with chest imaging abnormalities suspected of malignant disease. Several studies, meta-analyses, and systematic reviews specifically targeted the role of PET scan, EBUS-TBNA, and mediastinoscopy for detecting mediastinal lymph node involvement in patients suffering from lung cancer. Based on the recommendations from the currently published guidelines, algorithms of care are proposed for staging and restaging of the mediastinum.