Tracheal Collapse: Does My Patient Need a Tracheal Stent?

Overview

• Tracheal Stents: Designed primarily for palliation in canine tracheal collapse, which is a common condition in certain dog breeds.

• Historical Devices: The initial use of stainless-steel self-expanding metallic stents marked the advancement in managing this condition.

• Comparison with Prosthetic Rings: Stents offer a minimally invasive alternative with notably lower complication rates compared to traditional prosthetic rings, allowing for a more straightforward recovery process.

Clinical Outcomes

• Early Improvement: An impressive 95.8% of patients exhibited significant clinical improvement following stent placement, highlighting the effectiveness of this intervention in alleviating airway obstruction.

• Complications with "Open Wire" Design:

  • Pneumomediastinum: This serious condition occurred in 8.3% of cases post-stent placement, indicating a potential risk associated with the design of the stent.

  • Inflammatory Tissue Formation: A chronic issue affecting 27.8% of cases, leading to unwanted constriction of the tracheal lumen which can compromise airflow.

Alternative Stent Types

• Nitinol Suture-Released Stents (Sura et al., 2008):

  • Complications noted included stent malpositioning and migration. Long-term concerns included bacterial tracheitis, reported in 7 out of 12 dogs, and stent fracture in 5 out of 12 dogs, indicating the need for careful monitoring after placement.

• Endoscopy-Guided Self-Expanding Stents (Durant et al., 2012):

  • These stents utilize smooth, atraumatic ends and reconstrainable designs to reduce irritation. Acute complications included the onset of aspiration pneumonia in 3 out of 18 cases and stent fractures noted in 4 out of 18 cases, reflecting the risks inherent in this procedure.

Evolution of Vet-Stent Trachea

• Improvements (2004-Present): The design and material of stents have significantly improved, resulting in lower fracture rates and better patient outcomes.

• Tapered Stent Design: This new design provides enhanced resistance to compression compared to more traditional cylindrical designs, thereby improving the stent's overall functionality in the tracheal passage.

Clinical Considerations

• Indications for Stent Placement: Stenting is indicated for dogs experiencing significant airway obstruction that is unmanageable through medical interventions alone.

• Recognize that Stenting is a Palliative Solution: It is critical to understand that while stenting can relieve symptoms, it is not a cure for tracheal collapse.

Phenotypes of Tracheal Collapse

• Cervical and Thoracic Inlet Collapse: Characterized by airway obstruction and stridor, making timely intervention essential.

• Intrathoracic Collapse: Presents with cough and is generally less favorable for stenting, as these cases often indicate a more severe collapse.

• Cough without Significant Obstruction: Dogs exhibiting this symptom rarely benefit from stenting as the underlying issues differ.

Emergency Management

• Initial Crisis Treatment: Prioritizing airway management with endotracheal intubation is key; intravenous propofol can be used for anesthesia while thorough assessments are conducted.

• Palliative Medical Management: Appropriate treatment includes oxygen therapy, sedation (using acepromazine or butorphanol), corticosteroids, and antibiotics to manage inflammation and prevent infection.

Complications from Stent Placement

• Acute Risks: Include potential for malpositioning, migration, and risks of aspiration during recovery.

• Chronic Complications:

  • Foreshortening: A narrowing of the trachea due to radial force applied by the stent.

  • Fracture Risk: A persistent cough may exacerbate this risk, necessitating careful post-operative monitoring.

Client Education

• Expectations: It's essential to communicate that while immediate relief from airway obstruction is anticipated post-stenting, ongoing medical management and follow-ups are crucial for long-term care.

• Post-Operative Care: Hospitalization typically extends for one night, with a structured follow-up plan to monitor stent integrity and overall health of the patient.

References (Partial)

• Wall-Stent; Boston Scientific, Natick, MA USA.

• Vet-Stent Trachea; Infiniti Medical LLC, Menlo Park, CA USA.

• Clinical studies demonstrating outcomes and complications associated with the use of stents in veterinary medicine.