Aberrant migration and surgical removal of a heartworm (Dirofilaria immitis) from the femoral artery of a cat

Abstract

A cat was evaluated for an acute‐onset of right pelvic limb paresis. Thoracic radiographs revealed normal cardiac size and tortuous pulmonary arteries. Abdominal ultrasound identified a heartworm (HW) extending from the caudal abdominal aorta into the right external iliac artery and right femoral artery. The cat was HW‐antigen positive. Echocardiography revealed a HW within the right branch of the main pulmonary artery and evidence of pulmonary hypertension. An agitated‐saline contrast echocardiogram revealed a small right to left intracardiac shunt at the level of the atria. Surgical removal of the HW was performed with no substantial postoperative complications. There was return of blood flow and improved motor function to the limb. The cat remains mildly paretic on the affected limb with no other clinical signs.

Dirofilarioses in cats: European guidelines from the ABCD on prevention and management

“…38 Interestingly, HWD had been diagnosed in this cat 3 years earlier when it was evaluated for cough and successfully treated with prednisolone. 38 Laboratory diagnosis may reveal eos inophilia on complete blood count and on bronchoalveolar lavage cytology. Changes in concentrations of acute phase proteins have been described.…”

“…38 Interestingly, HWD had been diagnosed in this cat 3 years earlier when it was evaluated for cough and successfully treated with prednisolone. 38…”

“…Aberrant migrations (eg, to body cavities, central nervous system, femoral artery) are rare, but more frequently reported in cats than in dogs and are responsible for effusions or neurological manifestations (eg, blind ness, ataxia, paraparesis, monoparesis, seizures). 1,2,37,38 Acute-onset pelvic limb monoparesis due to femoral thrombo embolism was caused in a cat by a 13 cm adult female heartworm extending from the caudal abdominal aorta into the right external iliac and femoral arteries. 38 Interestingly, HWD had been diagnosed in this cat 3 years earlier when it was evaluated for cough and successfully treated with prednisolone.…”

“…1,2,37,38 Acute-onset pelvic limb monoparesis due to femoral thrombo embolism was caused in a cat by a 13 cm adult female heartworm extending from the caudal abdominal aorta into the right external iliac and femoral arteries. 38 Interestingly, HWD had been diagnosed in this cat 3 years earlier when it was evaluated for cough and successfully treated with prednisolone. 38 Laboratory diagnosis may reveal eos inophilia on complete blood count and on bronchoalveolar lavage cytology.…”

“…46,57 Successful surgical removal of an adult heartworm that had migrated to the femoral artery, achieved via direct access to the worm from the arteriotomy site, has been reported. 38 Slow kill protocols combining monthly administration of heartworm-preventive drugs with a 1-month course of doxycycline therapy are used in dogs when melarsomine is contraindicated, 58 and have been reported in cats, 21 but their efficacy and safety are unknown and therefore these protocols are not recommended. Nevertheless, all cats diagnosed with HWD should undergo monthly application of preventive drugs (see below).…”