A 10-year-old ovariohysterectomized female ring-tailed lemur with prior history of repeated examinations for perivulvar dermatitis, laceration repair, and suspected pneumonia presented for tachypnea. A right femoral arteriovenous fistula was diagnosed by the presence of a palpable thrill and continuous machinery murmur over the inguinal area, positive Branham’s sign, and suggestive ultrasonagraphic findings. Cardiac enlargement and mild pleural and abdominal effusion consistent with congestive heart failure were identified on radiographs and echocardiography. This animal was maintained on furosemide (0.5 mg/kg PO SID) until surgical ligation of the fistula was performed. Postoperative recheck examination confirmed successful closure of the fistula with resolution of the signs of heart failure.
Arteriovenous fistulas are abnormal connections between an artery and a vein which bypass the capillary bed. Acquired arteriovenous fistulas may result from invasive cardiovascular procedures, vascular trauma, or erosion of an arterial aneurysm.1,2 Large arteriovenous fistulas may result in an increase in cardiac output with consequent cardiomegaly and high output heart failure.1
This lemur’s high flow arteriovenous fistula with secondary heart failure is suspected to have resulted from prior femoral venipuncture based on the history and the anatomic location. To the authors’ knowledge, this is the first report of an arteriovenous fistula in a lemur. Surgical correction of a suspected iatrogenic arteriovenous fistula in a macaque has been previously reported.3 Arteriovenous fistula formation should be considered as a potential complication of venipuncture in primates and as a treatable cause of congestive heart failure.
1. Creager, M.A., and V.J. Dzau. 2005. Vascular diseases of the extremities. In: Kasper, D.L., E. Braunwald, A.S. Fauci, S.L. Hauser, D.L. Longo, J.L. Jameson (eds.). Harrison’s Principles of Internal Medicine, 16th ed. McGraw-Hill Co., New York, New York. Pp. 1486–1494.
2. Marsan, R.E., V. McDonald, and S. Ramamurthy. 1990. Iatrogenic femoral arteriovenous fistula. Cardiovasc. Intervent. Radiol. 13(5): 314–316.
3. Streett, J.W., P.F. Lord, and A. Schwartz. 198O. Iatrogenic arteriovenous fistula in a cynomolgus macaque (Macaca fascicularis): a case report. Lab. Anim. Sci. 30(6): 1012–1015.