Tracheal and bronchial stenting for treatment of airway collapse

Airway collapse (tracheal, bronchial or both) is a very common cause of chronic respiratory signs in dogs. While patient signalment may increase the suspicion of airway collapse in certain cases, for example tracheal collapse in Yorkshire Terriers or left mainstem bronchus collapse in Cavalier King Charles Spaniels with mitral valve disease, airway collapse should be considered as a major differential in any toy or small breed dog presenting with chronic respiratory signs. Clinical signs can include a chronic cough, decreased exercise tolerance, episodes of collapse/syncope, and heat intolerance. These clinical signs can be very worrying for pet owners and can severely affect the quality of life of both the patient and owner. More importantly, life-threatening sequelae can be seen in cases with advanced airway collapse and can include hypoxic episodes and pulmonary hypertension.

At SCVS, we offer both tracheal and bronchial stenting and stock a range of stent sizes so that patients presenting with acute deterioration or as an emergency can be treated without delay. Collapse of the left mainstem bronchus should be considered an important differential in any patient with mitral valve disease presenting with syncopal episodes or other signs such as coughing, which are refractory to cardiac medications or where there is no evidence of pulmonary oedema.

Key facts

• Stenting can result in significant improvement with regards to clinical signs and quality of life in a patient’s refractory to medical management
• Patients presenting with severe, life-threatening clinical signs can be treated without delay
• Bronchial collapse and stenting should be considered in patients with mitral valve disease and persistent clinical signs which are refractory to management with heart medications.

Positioning of the stent

Tracheal stent in position

Balloon dilation and stenting for nasopharyngeal stenosis and choanal atresia

Nasopharyngeal stenosis can be congenital or acquired while choanal atresia is a congenital condition. Both conditions can be seen in dogs and cats and these cases can present at any age. Clinical signs can include stridorous/loud breathing, retching, nasal discharge, reverse sneezing, and a preference for affected patients to breathe through the mouth. These signs can affect the patient’s quality of life and are worrying for pet owners. A definitive diagnosis can be made with CT and endoscopic examination of the nasopharynx. Treatment consists of balloon dilation of the stenotic area and this is performed using a combination of fluoroscopic and endoscopic visualisation. For cases refractory to ballooning, stenting can be considered.

Key Facts

• Consider as a differential in patients presenting with upper respiratory tract/nasal signs at a young age or those developing signs following episodes of regurgitation
• Interventional treatment can result in significant improvement with regards to clinical signs and patient quality-of-life
• Rapid recovery time from procedure.

Long-term pleural drainage / pleural port placement

Low-profile, permanent thoracic drainage via placement of a pleural port may offer a palliative management option for patients with recurrent pleural effusions, typically due to neoplastic disease. In some cases of intra-thoracic neoplasia, such as mesothelioma or carcinoma, the patients may remain relatively well, and the only clinical signs may be recurrent pleural effusion. Repeat thoracocentesis can be costly, time consuming and affects patient quality of life. With placement of a pleural port, such patients can be palliated long-term without the repeated need for therapeutic thoracocentesis. These ports are cosmetic and allow patients to enjoy a good quality of life when in place.

Key facts

• Minimally invasive, low-profile management option for patients with recurrent pleural effusion
• Negates the need for repeated thoracocentesis
• Rapid recovery time and short duration of hospitalisation

Minimally invasive treatment of nasal aspergillosis

Sinonasal aspergillosis is a common cause of nasal disease in dogs and reportedly account for up to 25%-30% of dogs with chronic nasal disease. The condition is seen most commonly in young-middle age, large breed or dolichocephalic dogs. Clinical signs can include nasal discharge (serious, purulent, haemhorrhagic), sneezing, epistaxis, depigmentation of the nasal planum, and signs of discomfort on touching the head. A definitive diagnosis can be made upon visualisation of fungal plaques (usually following CT) within the nasal cavities or sinuses. A diagnosis of Aspergillosis can frequently be missed if serology or nasal swabs are used as the sole tests as these have relatively low sensitivities. Treatment of sinonasal aspergillosis involves topical instillation of an anti-fungal medication, usually after debridement of fungal plaques. Oral anti-fungal medications are not recommended as the sole treatment given the low success/cure rate and potential for significant side-effects with long-term use. One of the most commonly employed methods for debridement and topical application of anti-fungal medications is surgical trephination of the sinus. While sinus trephination is an effective management option, we at SCVS are happy to also offer a minimally invasive treatment option. We can offer endoscopic debridement of fungal plaques from the nasal cavity and sinuses along with non-surgical instillation of antifungal medication into the affected nasal cavities and sinuses. Both the surgical and minimally invasive options typically involve two procedures to apply anti-fungal medications.

Key facts

• Less invasive with more rapid recovery time when compared to sinus trephination
• Response rate similar to surgical management with an expected cure rate of >90% following two applications
• More cosmetic appearance following procedure when compared to sinus trephination