Introduction and rationale

Benign airway stenosis or malacia is a frequent complication of lung transplantation occurring in 4-24% of patients, most often occurring two to nine months post-transplant. Initial therapeutic approach consists of conservative endobronchial treatment with recurrent balloon dilatation, radial incision, and electro cautery. For severe case of recurrent stenosis or malacia, airway stent placement can be considered. Different types of airway stent exist, for instance self-extendable metallic stent (SEMS), silicone stent and biodegradable airway stent. Conventional airway stents (SEMS, silicone) are associated with complications as granulation tissue and recurrent infections and can be difficult to remove. Newly developed biodegrabale stents are made of polydioxanone and disintegrate after a period of time are thought to have less side effects, and has been standard of care for the last few years. A sub selection of patients have been treated with conventional stent before treated with biodegradable stent.

Research question

• To assess the efficacy and efficiency of biodegradable airway stent.
• Compare occurrence of adverse events such as infection, dislocation, in stent granulation and difficulty of removal to conventional metallic or silicone stents.
• Asses if biodegradable stent lead to improvement of lung function.
• Assessment of the life span of biodegradable stents.

• Background Recurrent airway stenosis or malacia can be treated with airway stents. Conventional airway stents, for instance self-extendable metallic stent (SEMS) and silicone stent are associated with adverse events as recurrent infection or granulation tissue and can be difficult to remove because of in stent-granulation. Therefore they are used with restraint for benign airway problems. Biodegradable stents are made of polydioxanone and disintegrate after a period of time. They are thought to be well tolerated and associated with less adverse events compared to traditional airway stent and have been used as standard care for multiple years.

• Main research question

  • To assess the efficacy and efficiency of biodegradable airway stent
  • Compare occurrence of adverse events such as infection, dislocation, in stent granulation and difficulty of removal to conventional metallic or silicone stents.
  • Asses if biodegradable stent lead to improvement of lung function.
  • Assessment of the life span of biodegradable stents.

• Design (including population, confounders/outcomes) Retrospective cohort study of patients with airway stenosis or malacia treated with biodegradable airway stent from 2019 in the UMCG and Amsterdam UMC.

• Expected results

  • Less adverse events, hospital admittance and need for bronchoscopic interventions compared to patients treated with conventional stents. No complications associated with removal of stents.
  • Life span around 4 months

Inclusion Criteria:

• Patients who underwent a lung transplantation and developed airway stenosis or malacia with airway stent requirement

Exclusion Criteria:

• No