Update: This procedure is now available at several locations around the country.
Last year, we published a post on a promising new procedure, Percutaneous Transvenous Coil Embolization (PTCE) for the repair of liver shunts. The first scientific paper has come out on this procedure, but Dr. Cassie Lux, Assistant Professor of Surgery at the College of Veterinary Medicine at the University of Tennessee, very generously wrote up for us how the procedure works:
The procedure involves a small incision in the neck to access the jugular vein, through this vessel the entire procedure is completed with the aid of fluoroscopy. We place a vena cava stent at the mouth of the intrahepatic shunt to allow the thrombogenic coils to have something to pile up against during the procedure. These coils will continue to form clots over time.
The procedural complications are usually related to shunt anatomy itself. Some are more difficult than others to coil, but a majority of them are left and right divisional shunts (which tend to be quite amendable). Five to ten percent of dogs can only accept the vena cava stent at the first procedure because of dangerously high elevations in portal pressures, which is measured throughout the procedure. After stent placement if the pressures are safe, coils are placed into the shunt until portal pressures reach a value in which enough flow is attenuated to raise the pressures, but they are still within a safe range. Some dogs can take as few as 1-2 coils, some up to 13, etc.
Postoperative complications are similar to the extrahepatic shunts with regard to risk of seizures, at around 6-7%. Gastrointestinal hemorrhage can be life threatening in these dogs, and this risk continues throughout their entire life. Any dog with an intrahepatic shunt is recommended to be administered omeprazole* 1mg/kg BID for life to minimize this risk. There is a risk of bleeding from the jugular vein access site, although it’s uncommon. Anesthesia is a big concern in any PSS patient and occasionally they can have difficult recoveries or expire under anesthesia.
Long term, a majority of shunts will not completely occlude with their coils. In the reported cases (cited study) only 3-5% could have complete occlusion of their shunt at the time of surgery. However, even though most still had flow through their shunts 83% live a good quality of life (fair to excellent outcome) long term without a second procedure. 17% of dogs needed a second surgery to minimize clinical signs or effects from the patent shunt.
Second procedures are generally done 6 months or longer after first procedure to see full effects from the first round of coil placement. Reasons to perform a second procedure could include urinary stones, progressive hepatic encephalopathy signs, etc. Generally the dogs with persistent flow live the rest of their lives on omeprazole and a modified protein diet, without all other medications. Median survival times for all the dogs in the large group reported is around 6-7 years.
* Prilosec, available over the counter. (Ed.)
We asked Dr. Bill Culp, who is still studying this procedure at UC Davis Vet School, for clarification on some details:
Has a Deerhound been included in the study yet?
A Deerhound has not been treated yet.
It says in the article that gastrointestinal hemorrhage “is likely a separate, concomitant condition.” Have you learned anything else about this since this study was concluded?
For the gastrointestinal hemorrhage, this is something that we see associated with shunts (both treated and untreated). We know that this GI hemorrhage can occur long-term even after treatment.
In the paper, it reports a median survival time of 6-7 years, and long term, about 40% of the study dogs died from something related to the PSS or procedure, and a bit more than half died from unrelated things? Is the reduced life span because of the shunt, even in treated dogs?
The altered life span is due to the shunt, unfortunately. The procedure prolongs survival time as we know that the usual survival times with untreated shunts tend to be less than a year after diagnosis.
Several surgeons around the country are now also doing this procedure. Diagnostics and the procedure can run roughly from $6000-9000, although prices may vary around the country.