IRON STATUS AND ERYTHROCYTE VOLUME IN DOGS WITH CONGENITAL PORTOSYSTEMIC VASCULAR ANOMALIES

Microcytosis, hypochromasia, and low mean corpuscular hemoglobin are f requent hematologic abnormalities in dogs with portosystemic vascular anomalies (PSVA). The relationship of iron status to these abnormaliti es is unclear. We evaluated iron status and hematologic and biochemica l parameters in dogs with congenital PSVA before (25 dogs) and after ( 11 dogs) partial ligation of the vascular anomaly. Serum iron concentr ation and total iron binding capacity were subnormal in 56% and 20% of dogs with PSVA, respectively. Transferrin saturation was normal in 68 %, decreased in 20%, and increased in 12% of the dogs. Plasma ferritin concentration was either normal (56%) or high (44%), and was not asso ciated with increases in ceruloplasmin concentration. Hepatic stainabl e iron was increased in 10 of 16 dogs. Mean corpuscular volume (MCV), mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentra tion were decreased in more than 60% of dogs with PSVA. Serum biochemi cal abnormalities included high bile acid concentration and alanine tr ansaminase (ALT) and alkaline phosphatase (ALP) activities; and low ur ea, creatinine, cholesterol, and total protein concentrations. Serum i ron concentration and clinical status (normal or PSVA) significantly i nfluenced MCV (P = .003 and P < .001, respectively), whereas age, ceru loplasmin, ferritin, cholesterol, bile acids, and total iron binding c apacity did not, Partial ligation of PSVA was associated with resoluti on of clinical signs and the return to normal of iron status and all c linicopathologic abnormalities, except total fasting bile acid concent rations. These findings indicate that iron status is frequently abnorm al in dogs with PSVA and that low serum iron concentration appears to be related to the development of microcytosis. The normalization of ir on status and clinicopathologic abnormalities after treatment suggests that they are direct consequences of PSVA. Copyright (C) 1997 by the American College of Veterinary Internal Medicine.