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.