Tracheal collapse: old disease; newer treatment options (Proceedings)
Tracheal stent placement is a novel treatment option for dogs presenting with tracheal collapse refractory to traditional medical management and for those in which the nature and location of the collapse make them poor candidates for prosthetic ring placement. The goal of this handout is to provide the reader with a brief overview of tracheal collapse, treatment options, selection criteria for stent candidates, an overview of the technique, and the expected outcome.
Diagnosis & Medical Management of Dogs with Tracheal Collapse:
Despite the rapidly growing popularity of tracheal stents for the management of tracheal collapse, medical management remains the cornerstone of therapy. Only those refractory to medical management and those in which medical management is compromising quality of life are generally considered as candidates for tracheal stent placement or other palliative surgical options. The majority of dogs with tracheal collapse will present electively for evaluation of cough or a restricted or stridorous breathing pattern noted chronically by the owners. A tentative diagnosis of tracheal collapse is made based on signalment, clinical signs, and physical examination findings. Definitive diagnosis of tracheal collapse is based on various imaging modalities including thoracic radiography (3 view) to help rule out concurrent diseases as well as fluoroscopy and /or tracheobronchoscopy.Fluoroscopy is the author's preferred method for dynamic evaluation of tracheal collapse. The patient is allowed to spontaneously breathe, and cough while being imaged fluoroscopically. Using this technique, the extent of the tracheal collapse and the presence of main stem bronchial (MSB) collapse can be evaluated. This information is valuable when determining optimal definitive treatment measures (surgery for prosthetic ring placement vs. tracheal stent placement).
Tracheobronchoscopy performed under general anesthesia is a preferred technique for some to evaluate the extent of the tracheal collapse and to grade its severity while concurrently identifying the presence of MSB collapse.
It is important to ascertain the presence of MSB collapse because the presence of MSB collapse significantly impacts response to treatment (and persistence of cough). Finally, the author always evaluates the larynx for evidence of dysfunction, structural abnormalities (collapse), or the presence of a mass.
Medical management is always attempted for the management of dogs with tracheal collapse prior to other interventions (surgery or tracheal stent placement). Anti-inflammatory doses of corticosteroids have a significant place in both the acute and chronic management of dogs with tracheal collapse. Injectable forms of corticosteroids equivalent to prednisone (0.5-1mg/Kg/day) may be administered soon after presentation in an effort decrease tracheal inflammation. Corticosteroid therapy should be weaned beginning one week after treatment begins to a level that is low enough to optimally control clinical signs. To the authors' knowledge, the efficacy of corticosteroid administration in the acute management of tracheal collapse has not been objectively investigated.
Initiating therapy with hydrocodone (0.22mg/Kg PO Q6hrs PRN) is effective for cough suppression. Cough is a significant complaint for many dogs with tracheal collapse, especially those with intrathoracic and main stem bronchial collapse. Finally, comorbid conditions should be treated concurrently.
Palliative Treatments for Dogs with Tracheal Collapse:
When medical management cannot adequately control clinical signs of tracheal collapse such that quality of life is compromised, palliative interventions (surgery for prosthetic ring placement or tracheal stent placement) must be considered. It is critical for the client to accept that these interventions are palliative and will not cure the problem. Instead, the goal of these procedures is an improvement in clinical signs and less reliance on medical therapies.
If the tracheal collapse is only in the cervical region and at the level of the thoracic inlet, surgical placement of prosthetic tracheal rings is a reasonable consideration. It should be noted however, that the success of this procedure is very operator dependent. Intraluminal placement of a self-expanding metallic stent is a rapid, relatively simple procedure that can restore the patency of the tracheal lumen without the need for open surgical intervention.
Tracheal Stent Case Selection Criteria:
Tracheal stent placement is an option, but is not considered optimal by the author for all dogs with tracheal collapse. Younger to middle-aged dogs with cervical collapse and collapse at the thoracic inlet in need of elective intervention may be best treated through placement of prosthetic rings. The reason for this is (at this time) the increased durability of prosthetic rings over time. Tracheal stent fracture and subsequent mechanical failure has been a recognized complication of tracheal stent placement whereas failure of prosthetic rings would be considered extremely rare.
Tracheal stents are most often placed in dogs with intrathoracic collapse or those with diffuse tracheal collapse. In addition, the author will often recommend tracheal stent placement over prosthetic rings in extremely small patients, in those that are extremely old, those with many comorbidities, and those that present intubated in the emergency setting and cannot be extubated due to airway obstruction. Finally, some clients will elect a minimally invasive treatment option over open surgical intervention (prosthetic rings) even if surgical intervention is perceived to be the superior treatment option.