Transcatheter intravascular stent placement to relieve supravalvular pulmonic stenosis

Valvular pulmonic stenosis has been successfully treated in dogs via minimally invasive transcatheter balloon dilation procedures for almost 20 years. Supravalvular pulmonic stenosis however is not amenable to balloon dilation procedures. Although several surgical procedures are described for treatment of pulmonic stenosis, the morbidity and mortality of these procedures are significantly higher than for transcatheter approaches.Two cases of supravalvular pulmonic stenosis are presented, one acquired and one congenital, which were successfully treated with transcatheter intravascular stent placement. The procedure alleviated the stenotic lesion and resolved clinical signs.     

Half-Body Radiotherapy

Eight healthy mongrel dogs were treated with half-body irradiation (HBI) in a pilot study to evaluate the technique and radiotolerance of different organs. Cranial and caudal half-body fields were established using the 13th thoracic vertebra as the dividing point. Under general anesthesia, either 7 or 8 Gray (Gy) were delivered to one half of the body using opposing radiation portals. The other half of the body was similarly treated 28 days later. The dogs were monitored for 12 months. Significant radiation effects included transient bone marrow suppression and radiation sickness. There were no serious or life-threatening problems, but the 8 Gy group consistently showed more severe clinical signs and histologic changes than the 7 Gy group. Total body irradiation in two fractions of 7 or 8 Gy given 1 month apart appears to be a safe treatment that can be developed for therapy in veterinary oncology.     

Half-Body Radiotherapy in the Treatment of Canine Lymphoma

In a Phase I-II study, half-body radiotherapy was used to treat 14 dogs with multicentric lymphoma. Using this technique, a radiation dose of 7 Gray (Gy) was delivered to one half of the body in a single exposure. The other half of the body was treated approximately 28 days later. Of 14 treated dogs, 11 (79%) had a measurable decrease in tumor size. Five dogs achieved a complete or partial remission with a mean duration of 102 and 54 days, respectively. In predicting response to therapy, poor prognostic factors included large tumor burdens, advanced disease stage, and chemotherapy-resistant tumors. Side effects of treatment were divided chronologically into acute (radiation sickness, tumor lysis), subacute (bone marrow suppression), and chronic (radiation pneumonitis, lymphoma-cell leukemia) syndromes. Complications were more severe in tumor-bearing dogs when compared with healthy control animals. Dogs with small tumor burdens and minimal internal disease had fewer complications compared with those with more advanced disease.