Ultrasonographic assessment of hemodynamic changes in the portal vein during surgical attenuation of congenital extrahepatic portosystemic shunts in dogs.
OBJECTIVE
To determine portal hemodynamic changes associated with surgical shunt ligation and establish ultrasonographic criteria for determining the optimal degree of shunt narrowing and predicting outcome.


METHODS
Case series.


METHODS
17 dogs, each with a single congenital extrahepatic portosystemic shunt.


METHODS
Pre- and postligation flow velocities and flow directions were determined by Doppler ultrasonography intraoperatively in the shunt and in the portal vein cranial and caudal to the shunt origin. Outcome was evaluated 1 month after surgery by measuring blood ammonia concentration and performing abdominal ultrasonography.


RESULTS
Hepatofugal flow was detected in 9 of 17 dogs before shunt attenuation in the portal segment that was between the shunt origin and the entering point of the gastroduodenal vein. If hepatofugal flow became hepatopetal after shunt ligation, hyperammonemia resolved. Hepatofugal portal flow was caused by blood that flowed from the gastroduodenal vein toward the shunt. Shunt attenuation converted hepatofugal flow to hepatopetal in the shunt in 12 of 17 dogs. Chronic portal hypertension developed or perioperative death occurred when the portal congestion index caudal to the shunt origin increased by > 3.6 times.


CONCLUSIONS
After hepatopetal flow in the cranial portal vein and the shunt is established, further shunt narrowing is contraindicated. Increase of the portal congestion index caudal to the shunt > 3.5 times should be avoided. Poor outcome because of severe hypoplasia of the portal branches can be expected if the flow direction remains hepatofugal after shunt occlusion cranial to the shunt origin.
Szatmári
Viktor
V
Division of Diagnostic Imaging, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
van Sluijs
Frederik J
FJ
Rothuizen
Jan
J
Voorhout
George
G
D000818:Animals; D001783:Blood Flow Velocity; D004285:Dogs / Q000097:blood*; D005260:Female; D006439:Hemodynamics; D008026:Ligation / Q000662:veterinary; D008297:Male; D011168:Portal System / Q000002:abnormalities* / Q000601:surgery; D011169:Portal Vein / Q000000981:diagnostic imaging* / Q000502:physiology / Q000601:surgery; D011183:Postoperative Complications / Q000662:veterinary; D016896:Treatment Outcome; D018615:Ultrasonography, Doppler, Color / Q000379:methods / Q000662:veterinary