Stormie, a 4-year-old female Siamese with a history of heartworm disease since she was 1 year old, was with her owner while she visited family in the Bay Area when one of her rear legs became lame. Stormie’s owner brought her to a local veterinary emergency room in Berkeley, where she shared the cat’s history. After an ultrasound showed a suspected heartworm in the arterial system, and a heartworm antigen test resulted in a strong positive, Stormie’s owner was advised to bring her to specialists at the UC Davis veterinary hospital.
Once at UC Davis, the Cardiology Service confirmed the diagnosis and performed an echocardiogram, only to find a heartworm located in the pulmonary artery and evidence of pulmonary hypertension from heartworm disease.
An abdominal ultrasound confirmed that the heartworm extended into her abdominal aorta and down her leg into the right femoral artery, cutting off blood supply to the right leg. Immediate attention was necessary in order to avoid amputation.
A CT angiography scan revealed no additional heartworms. However, it did find abnormalities in the soft tissues in the right back leg, likely secondary to decreased blood flow from the worm, as well as evidence of lung inflammation also likely caused by the heartworms.
Catherine Gunther-Harrington, DVM, DACVIM (cardiology), and Ingrid Balsa, MEd, DVM, of the Soft Tissue Surgery Service, assisted by cardiology resident Maureen Oldach, DVM, collaborated to successfully remove the 13-centimeter heartworm from Stormie’s right femoral artery without breaking it. Because normal blood flow through the artery was restored once the worm was removed — and the leg tissue still looked healthy — the artery was repaired, and the doctors decided that amputation was unnecessary. However, Stormie’s leg may require amputation in the future if the nerves and muscle in that leg do not heal properly, which may take months.
Stormie remained hospitalized for four days so the Intensive Care Unit team could closely monitor her recovery. In addition to painkillers and anti-inflammatory medications, she was given an antibiotic to help weaken the remaining heartworms in her system, as well as an anticoagulant to break and prevent clotting, and, of course, a monthly heartworm preventative that she will need to continue for the rest of her life.
To avoid a future amputation, Stormie’s owner has her in physical rehabilitation and is hopeful that she will continue to improve.