Outcome of minimally invasive surgical treatment of heartworm caval syndrome in dogs: 42 cases (1999-2007)

Objective - To report the outcome of minimally invasive surgical treatment of heartworm caval syndrome in a series of dogs and to provide information on long-term survival of patients with this condition. Design - Retrospective case series. Animals - 42 client-owned dogs with a diagnosis of heartworm caval syndrome. Procedures - Information on history, clinical, laboratory, and diagnostic imaging findings and treatment was obtained from medical records. When possible, additional follow-up information was obtained through telephone interviews with referring veterinarians and owners. Results - Of the 42 dogs with caval syndrome, 21 underwent minimally invasive surgical treatment consisting of transvenous heartworm extraction. Two of the 21 dogs died during the procedure, and after surgery, 4 died. Following induction of anesthesia, heartworms migrated into the distal portion of the pulmonary artery in 1 dog; therefore, extraction was not attempted. Transvenous heartworm extraction was completed successfully in 14 dogs, and all 14 of these dogs were discharged from the hospital. Mean follow-up time in these 14 dogs was 24.4 ± 17.7 months with a range of 2 to 56 months. At the time of final follow-up, 10 of these 14 dogs had survived at least 18 months and 7 had survived > 24 months. By the end of the study, 1 dog was lost to follow-up and 3 had been euthanatized for unrelated reasons. Conclusions and Clinical Relevance-Results of the study reported here suggest that dogs with caval syndrome that undergo successful transvenous heartworm extraction and survive to discharge have a good long-term prognosis.