# Removable airway stents that preserve mucociliary function

> **NIH NIH R41** · DOWN FROM THE DOOR, LLC · 2021 · $303,769

## Abstract

PROJECT SUMMARY
Tracheobronchomalacia, while a rare disease, is observed in up to 13% of adult patients who undergo
bronchoscopic examination for respiratory symptoms and up to 23% of patients with chronic bronchitis. Intrinsic
weakness of the cartilage and/or fibromuscular membrane leads to collapse resulting in air trapping and poor
gas exchange. Symptoms include labored breathing, episodic choking, chronic cough and periodic respiratory
infections. While continuous positive airway pressure (CPAP) can be used to prevent collapse, it is difficult to
perform everyday activities while using CPAP 24 hours a day. A number of surgical procedures have been
developed to reinforce the airways and so prevent collapse, but these involve major surgery and have high
complication rates. Alternatively, while stents can be used to prevent airway collapse, existing airway stents are
ineffective. Metal mesh stents induce the growth of granulation tissue through the mesh requiring a very invasive
removal procedure. To avoid this, solid silicone tubes have been developed, but they too have shortcomings.
They migrate easily along the airways and block mucociliary function over the length of the stent resulting in
mucous plugging. Resorbable stents are intended to overcome the challenge of removal, but stent fragmentation
during resorption can block distal airways. To address this clinical need, a Boston Children’s Hospital (BCH)
team, comprised of surgeons, pulmonologists and engineers, has created a helical stent technology and tested
it using in vivo animal experiments. These stents allow mucociliary flow and their screw-like shape prevents them
from migrating once positioned in the airways. They can also be removed with minimal damage even if
epithelialized using a novel bronchoscopic tool that employs an unscrewing motion to retract the stent from the
tissue and into a cannula for removal. The BCH team has joined forces with DFD Solutions to commercialize
this technology. As an initial step toward a 510(k) application, this project proposes two Specific Aims. In the first
aim, we will evaluate the efficacy and safety of our stent system in a malacic animal model matched the
dimensions of an adult human trachea. These 12-week experiments will be of sufficient duration to enable
evaluation of stent performance over a clinically relevant time period. Bronchoscopy will be used to evaluate
airway patency, the formation of granulation tissue, mucus clearance, stent migration and the ease of stent
removal. We will also employ histological techniques to assess tissue damage, granulation tissue, fibrosis and
inflammatory response. Aim 2 will focus on designing the stent and tools for clinical use by defining the critical
requirements and features that will enable use within existing clinical workflows. This will include conducting
human-factors research to obtain procedural and process maps for the system as well as engineering design to
define user / technical requirem...

## Key facts

- **NIH application ID:** 10258203
- **Project number:** 1R41HL158451-01
- **Recipient organization:** DOWN FROM THE DOOR, LLC
- **Principal Investigator:** Pierre E Dupont
- **Activity code:** R41 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $303,769
- **Award type:** 1
- **Project period:** 2021-05-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10258203

## Citation

> US National Institutes of Health, RePORTER application 10258203, Removable airway stents that preserve mucociliary function (1R41HL158451-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10258203. Licensed CC0.

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