Introduction

This study aims to evaluate the long-term outcome of the ameroid constrictor (AC) as the sole method of surgical occlusion for congenital portosystemic shunts in 20 cats.

Methods and Materials

The medical records of cats treated for PSS with AC at Oakwood Referrals, between October 2000 and October 2006, were reviewed. Data retrieved included: breed, sex, weight, age at surgery, presenting clinical signs, biochemical and haematological data, location of shunt vessel, size of AC used, length of hospitalisation pre and postoperatively and postoperative complications.

Thirteen out of 20 owners responded to a postal questionnaire. Of the remaining seven, five were contacted by telephone and two were lost to follow-up. The opinion of the owners on the outcome of surgery was obtained between 12 and 84 months (mean 41.4 months, median 39.5 months) after the surgical procedure.

Results

Similar results were obtained for age and breed distribution to those seen in previous studies. The most commonly affected breeds were the domestic short hair (n=7) and Birman (n=6). The most common presenting signs were hepatic encephalopathy and ptyalism. Serum biochemistry and haematological data were similar to those in previous studies. All patients had raised fasting and/or postprandial bile acid levels.

Eight of the twenty patients (40%) displayed postoperative neurological dysfunction and of these, 5 cats (25%) died or were euthanased as a result. Of the 6 cats not requiring hospitalisation before surgery and who exhibited no neurological dysfunction in the immediate post-operative period, 5 (83%) went on to make full recoveries.

Fifteen out of the 20 cats (75%) went on to make a good long term recovery irrespective of the length of hospitalisation or neurological dysfunction.

Of the 18 owners contacted only 1 (5.6%) described their cat as having suffered complications as a result of surgery.

100% of contacted owners said that they did not regret having their cat operated upon and would choose surgery if they were to have another cat with PSS.

In conclusion, ameroid constrictors can provide a good outcome for some PSS in cats. Cats exhibiting post-operative neurological dysfunction have a poorer prognosis than those without.