Global Incidence and Prevalence of Central Airway Stenosis

Based on a comprehensive review of recent literature, there is a notable gap in epidemiological data regarding the global incidence and prevalence of central airway stenosis. Current PubMed-indexed research does not provide specific global incidence rates for central airway stenosis or its subtypes, including tracheal stenosis, main bronchial stenosis, and subglottic stenosis.

The most recent publications from 2022 only mention "scarring central airway stenosis" as a condition manageable through various interventions, without providing epidemiological data on its occurrence worldwide. The available literature primarily consists of case reports rather than large-scale epidemiological studies.

For instance, one 2022 publication describes two case reports of tracheobronchial stenosis following injury that were treated with pirfenidone in combination with interventional management. Another publication from the same year details a single case of a 57-year-old man with high grade epithelioid angiosarcoma of the right lung and pleura who required placement of a tracheal stent.

Despite the clinical significance of central airway stenosis, there appears to be a lack of comprehensive epidemiological research that would provide reliable estimates of its global incidence or prevalence rates. The absence of such data represents a significant knowledge gap in understanding the true burden of this condition across different populations and geographical regions.

The literature does not currently offer stratified data by etiology such as post-intubation, neoplastic, inflammatory, idiopathic, or traumatic causes. Similarly, there is no information available regarding how these rates might vary by geographical region, patient demographics, or healthcare infrastructure.

This lack of epidemiological data highlights the need for more robust, population-based studies to better understand the true global burden of central airway stenosis and inform appropriate resource allocation for its management.

Study Design Parameters and Endpoints in Central Airway Stenosis Trials

Study Designs

• Cross-sectional, descriptive, prospective study (2010) with 180 subjects comparing Vitalograph-COPD-6 with conventional spirometry
• Single-arm, open-label study (2015) evaluating LVR coil treatment in homogeneous emphysema patients
• Validation study (2018) with 7 expert bronchoscopists and 7 general pulmonologists assessing SENSA software
• Retrospective single-center cohort study (2023) evaluating a novel segmentation-based volume rendering approach for benign central airway obstruction (BCAO)
• Pilot study (2024) with 10 patients evaluating a novel prototype measurement device (LJ system)
• Computational fluid dynamics analysis (2023) on 36 synthetic and 8 patient-specific airway models

Patient Populations

• Patients with tracheal stenosis with suspected benign etiology
• Patients with severe airway obstruction and hyperinflation
• Patients with Malignant Central Airway Obstruction (MCAO) from primary lung cancer or metastatic disease
• Patients with tracheal stenosis indicated for Y-stent placement or open surgery
• Patients with tracheoesophageal fistula

Measurement Methods

• Vitalograph-COPD-6 portable device versus conventional spirometry
• SENSA (System for Endoscopic Stenosis Assessment) for objective stenosis measurements
• Segmentation-based volume rendering approach using OsiriX software
• LJ system with probe, display box, encoder, and microcontroller
• 3D reconstruction with computational fluid dynamics simulations
• Pressure sensor plethysmography using two pressure sensors

Key Endpoints

• FEV₁/FEV₆ ratio compared to FEV₁/FVC for detecting airway obstruction
• Stenosis Index (SI) measurements with precision up to 99.5%
• Interrater reliability calculated by intraclass correlation coefficient (ICC)
• Pressure drop, area-average velocity, volume flow rate, wall shear stress, and airflow resistance
• 6-minute walking distance (6MWD) improvement from baseline
• Forced vital capacity (FVC) and residual volume measurements
• St. George's Respiratory Questionnaire scores for quality of life assessment
• Technical success and symptomatic relief in therapeutic bronchoscopy

Key Findings

• 70% constriction marks the onset of a precipitous decrease in airflow
• ICC of 0.88 (95% CI, 0.84 to 0.93) for volume rendering approach, indicating good to excellent agreement
• ICC of 0.38 (95% CI, 0.20 to 0.55) for subjective methods, indicating poor to fair agreement
• Tracheal stenosis significantly influences peripheral bronchi resistance
• LVR coil treatment improves hyperinflation, airway resistance, exercise capacity and quality of life

• In a 2015 multicenter registry study of therapeutic bronchoscopy for MCAO:

• Technical success (reopening airway lumen to >50% of normal) achieved in 93% of procedures

• Clinically significant improvements in dyspnea occurred in 48% of patients

• Clinically significant improvements in HRQOL occurred in 42% of patients

• Endobronchial obstruction and stent placement were associated with success

• ASA score >3, renal failure, primary lung cancer, left mainstem disease, and tracheoesophageal fistula were associated with failure