Surgical correction of an arteriovenous fistula in a ring-tailed lemur (Lemur catta)

A 10-y-old ovariohysterectomized ring-tailed lemur (Lemur catta) was presented for exacerbation of respiratory signs. The lemur had a history of multiple examinations for various problems, including traumatic lacerations and recurrent perivulvar dermatitis. Examination revealed abnormal lung sounds and a femoral arteriovenous fistula with a palpable thrill and auscultable bruit in the right inguinal area. A diagnosis of congestive heart failure was made on the basis of exam findings, radiography, abdominal ultrasonography, and echocardiography. The lemur was maintained on furosemide until surgical ligation of the fistula was performed. Postoperative examination confirmed successful closure of the fistula and resolution of the signs of heart failure. Arteriovenous fistulas are abnormal connections between an artery and a vein that bypass the capillary bed. Large arteriovenous fistulas may result in decreased peripheral resistance and an increase in cardiac output with consequent cardiomegaly and high output heart failure. This lemur's high-flow arteriovenous fistula with secondary heart failure may have been iatrogenically induced during blood collection by prior femoral venipuncture. To our knowledge, this report is the first description of an arteriovenous fistula in a prosimian. Successful surgical correction of suspected iatrogenic femoral arteriovenous fistulas in a cynomolgus monkey (Macaca fascicularis) and a rhesus macaque (Macaca mulatta) have been reported previously. Arteriovenous fistula formation should be considered as a rare potential complication of venipuncture and as a treatable cause of congestive heart failure in lemurs.