Redirection of Blood Vessels May Cure Congenital Condition
Acknowledging that some veterinary cases require mechanical – versus medicinal – care, researchers at the University of Florida have successfully tested a new surgical approach to curing a rare but often fatal vascular malfunction called congenital intrahepatic portosystemic shunts (CIPS).
“We tell clients that it’s a plumbing problem that has to be fixed mechanically,” said Christopher Adin, DVM, DACVS, who has tested the surgery on 16 client-owned dogs.
CIPS is caused by shunts that redirect blood vessels to the heart and systemic circulatory system instead of going through the liver, which acts as a filter. If left untreated, CIPS causes liver failure and can be fatal within two to three years, Adin said. It occurs primarily in large purebred dogs such as retrievers, Scottish deerhounds and Irish wolfhounds, though it is also diagnosed in small dogs.
Symptoms include lethargy, gastrointestinal problems, blindness, and stunted growth. Once lab tests confirm liver failure, advanced imaging is used to detect the shunts, Adin added.
The study took place at the University of Florida teaching hospital between January 2004 and February 2005, and focused on large breeds because it is more difficult to access the abnormal blood vessels, Adin said. Since completion of the study, an additional six dogs have had the surgery. Adin may consider trying the surgery on smaller dogs in the future.
The new procedure, which has been replicated in two United States specialty facilities, is intended to close shunts gradually to avoid spikes in blood pressure. Surgeons implanted silicone cuffs around aberrant blood vessels, and injected sterile saline into ports underneath the skin.
Dogs that were referred from specialty clinics as well as general practitioners in the area received eight injections every two weeks, which Adin likened to administration of chemotherapy drugs. Over the eight-week time span the devices were closed down.
Alternatives to the surgery include tying silk sutures around shunts, but that approach can raise blood pressure and cause mortal hypertension, Adin said.
“Dogs cannot tolerate the sudden closure of the blood vessel,” he explained. In comparison, shunts employed during Adin’s surgery are closed gradually to avoid inflammation. “Inflammation is difficult to control in the body,” he said. “And we don’t like methods that are out of our control.”
Eight of the 10 dogs included in the study are still alive and the two deaths were not directly related to the surgery, Adin said. There were initial problems with three of the first six dogs that received the treatment, including a device that burst, and a tube that disconnected from the port, but they have been rectified, Adin said.
Described as challenging, the three-hour surgery has been replicated in New York and Colorado, and costs approximately $2,000 to $3,000 in clinics for the surgery and required hospital stay. Costs for the 10 study dogs were covered by a Morris Animal Foundation grant.