Tracheal Stenosis Caused by Thoracic Malignancy: Correlation between CT-Based Tracheal Measurement and Spirometric Values before and after Tracheal Stenting

Shinya Azagami,Teruomi Miyazawa,Shin Matsuoka,Hiroshi Handa,Tsuneo Yamashiro,Takeo Inoue,Masamichi Mineshita

doi:10.4236/ojmi.2017.73007

Abstract

Background: The correlation between computed tomography (CT)-based tracheal size and spirometry values is unknown in patients with tracheal stenosis by thoracic malignancy, which is often treated by tracheal stenting. Objectives: To evaluate the correlation between the tracheal cross-sectional area (CSA) and spirometric values before and after tracheal stenting, and to confirm that greater improvement in tracheal CSA leads to a larger improvement in spirometry values. Methods: A total of 32 patients with malignant tracheal stenosis underwent tracheal stenting. Before (n = 32) and after (n = 27) treatment, patients underwent chest CT, measuring mean and minimum tracheal CSA values, and spirometry. The correlation between tracheal CSA and each spirometric value was evaluated using Spearman rank correlation analysis. Differences in the pre- and posttreatment tracheal CSA and spirometric values were evaluated using the Wilcoxon matched-pairs test. Results: Significant improvement in the minimum tracheal CSA and in spirometric values was observed after stenting (P P P < 0.05). Conclusions: The tracheal size measured on chest CT correlates with patients’ spirometric values, particularly at the prestenting examination, in patients with malignant tracheal stenosis. The increase in the minimum tracheal CSA after stenting on CT is a predictor for improved spirometric values, which is first demonstrated by this study.

Highlights

Tracheal stenosis is often caused by thoracic malignancy, typically by direct tracheal invasion of primary cancers, external tracheal compression by lymph node metastases, and luminal narrowing by endoluminal tracheal malignancies
We demonstrated that 1) computed tomography (CT)-based tracheal cross-sectional area (CSA) measurements, the minimum tracheal CSA before stenting, are significantly correlated with spirometric values in patients with malignant tracheal stenosis; and 2) the increase in the minimum tracheal CSA created by stenting is significantly correlated with improvements in spirometric values
It is already known that the choke-point of the central airway is responsible for airflow limitation and the patient’s symptoms; this choke-point is usually identified by bronchoscopy, chest CT, or impulse oscillometry [17] [23] [24]

Summary

Introduction

Tracheal stenosis is often caused by thoracic malignancy, typically by direct tracheal invasion of primary cancers, external tracheal compression by lymph node metastases, and luminal narrowing by endoluminal tracheal malignancies. A simulation analysis and a bronchoscopic study measuring intratracheal pressure showed that constriction of over 70% of the tracheal lumen causes severe airflow reduction [2] [3]. They are usually palliative treatments, bronchoscopic interventions have been developed for and used in symptomatic patients with malignant tracheal stenosis. The correlation between computed tomography (CT)-based tracheal size and spirometry values is unknown in patients with tracheal stenosis by thoracic malignancy, which is often treated by tracheal stenting. Before (n = 32) and after (n = 27) treatment, patients underwent chest CT, measuring mean and minimum tracheal CSA values, and spirometry.

Objectives

Methods

Results

Conclusion