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Outcome of cholecystectomy in dogs for the treatment of gallbladder disease | VETgirl Veterinary Continuing Education Podcasts

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Ah, the mucocele. The disease that internists want to surgical treat, and the ones that surgeons want to medically manage.

In this VETgirl online veterinary continuing education podcast, we review the outcome in dogs undergoing cholecystectomy for the treatment of gallbladder disease. When it comes to dogs undergoing cholecystectomy, what’s the prognosis? Should we be rushing dogs with gallbladder disease to surgery? What clinical signs and clinicopathologic changes should we be looking for? Well, previous studies have looked at gall bladder disease and reported mortality rates for dogs undergoing cholecystectomy ranging from 7-33.3%, with a better prognosis for dogs specifically undergoing cholecystectomy for a gall bladder mucocele (GBM).(1-5) Multiple studies have evaluated signalment, diagnostic imaging, anesthetic complications, and overall survival with gallbladder disease. Based on some of these studies, several breeds have an increased risk of GBM formation, including Shetland Sheepdogs, Cocker Spaniels and Miniature Schnauzers. Shelties were found to have 7.2X the risk of development of GBM versus other breeds.6 Patients with GBMs can have vague GI clinical signs or no signs at all.2,3,4 In two studies, 44% of dogs with GBMs diagnosed on ultrasound were being scanned for a different disease process or high liver enzymes with no clinical signs of a GBM.6,7

Well, Youn et al out of VCA Animal Specialty Center of South Carolina wanted to evaluate this in a study called Outcome of elective cholecystectomy for the treatment of gallbladder disease in dogs.8 The authors retrospectively evaluated mortality rates in dogs undergoing cholecystectomy and reviewed variables associated with failure to survive to hospital discharge between 2009-2015 in this referral hospital. A total of 70 dogs were included in this study. In this study, dogs that underwent cholecystectomy as an elective (in other words, dogs with no or mild clinical signs, no evidence of biliary obstruction or underwent surgery for another procedure) or non-elective (icterus, possible biliary obstruction) procedure were compared. What’d they find? Overall, 64% of dogs had surgery as an elective procedure, while 36% needed surgery imminently (e.g., nonelective group). The overall mortality rate was 9%, with 2% in the elective group and 20% in the non-elective group. 31% of dogs had no clinical signs at the initial evaluation. Of those dogs showing clinical signs, the most common signs were anorexia or inappetence (43%), vomiting (41%), lethargy (33%) and icterus (23%).

There was no significant association made between presence or absence of clinical signs overall (i.e. yes or no for any clinical signs) and survival to discharge. However, when the authors broke down “signs” into specific clinical symptoms (e.g., was the patient vomiting or not? Was he icteric or not?, etc.) then the authors found significance for 4 specific signs (vomiting, lethargy, anorexia and icterus). Meaning, dogs with one or more of these 4 specific signs were statistically less likely to survive to hospital discharge than dogs without these signs. Icterus, an indicator of advanced hepatobiliary disease, was present solely in the non-elective group, suggesting that by the time dogs are icteric they are already feeling clinically ill and may have a worse prognosis post-op. The presence of the specific clinical signs of vomiting, anorexia, lethargy or icterus made patients more likely to fail to survive to discharge. For example, if a GBM was found on ultrasound and the patient was completely normal (e.g., asymptomatic), the prognosis was better than if they found a GBM and the patient was symptomatic (e.g., icteric). Confused? Pull the paper here.

When evaluating clinicopathologic data in this study between the elective versus non-elective surgery groups, they found that dogs in the non-elective group were more likely to have elevations in ALT, ALKP, GGT, bilirubin and WBC counts and decreases in albumin. The remaining lab values were similar between the elective and non-elective groups. When looking at the survival data, they found that of the lab values evaluated, only changes in ALT and bilirubin and hypoalbuminemia were significantly associated with outcome. In other words, ALT and bilirubin were significantly higher and albumin was significantly lower in non-survivors.

In dogs that had advanced imaging (e.g., abdominal ultrasound), 96% (67/70) of patients had descriptions of the ultrasonographic appearance of the gall bladder (GB) available; 54% had evidence of a GBM (e.g., stellate or kiwi appearance to the GB), while the remaining 46% had mineralization within the GB or GB distention with hyperechoic or organized sediment.

When looking at comparisons between the ultrasonographic and surgical findings in these patients, they didn’t always correlate, especially when it came to evidence of focal peritonitis, GB or biliary tree rupture, or the presence of abdominal effusion. This tells us that even patients without any evidence of impending or imminent rupture on ultrasound may still have these findings identified at surgery. The good news is that presence of these findings at surgery were not associated with outcome.

When looking at surgery specifically, many of these patients had other surgical procedures performed, including things like feeding tube placement, splenectomy, other GI surgery, liver biopsies and cystotomies, to name a few. Whether related to GB disease or not, these other surgical procedures were not associated with outcome. At surgery, 58% of dogs did not have either aspiration of the duodenum or catheterization of the bile duct performed to confirm bile duct patency. However, it was reported that this step was not performed mostly because bile duct patency was identified visually without an additional procedure. While no statistical assessment was done on patients that did or did not have duodenotomy or aspiration of the duodenum performed, no patient required re-operation for bile duct obstruction during their hospitalization. This may be of interest as there are conflicting opinions on whether or not these additional procedures are necessary to confirm bile duct patency in cholecystectomy patients. Another interesting fact related to surgical findings and alluded to above was that in 4 of the patients, gall bladder or biliary tree rupture was confirmed, but this did not significantly impact outcome.

While knowing what is associated with outcome is important, knowing what did not affect outcome is beneficial as well. In this study, variables that were assessed and not significantly associated with outcome included intra-operative hypotension, duration of hospitalization, gall bladder/biliary tree rupture, positive bile bacterial culture, adjunct surgical procedure, or the presence of abdominal effusion. FYI, despite the fact that positive bacterial culture was not associated with outcome in this study, this is not the case in human medicine. For this reason, peri- and post-operative antimicrobial administration is recommended, especially if GB rupture is suspected.2,6

So, what do we take from this VETgirl podcast? Dogs undergoing elective cholecystectomy (before clinical signs develop) have a significantly better prognosis than dogs requiring non-elective cholecystectomy, and have a lower mortality rate than previously reported. This can be helpful when discussing surgical recommendations and timing with owners. This study supports the notion that surgical intervention for patients with an ultrasonographic diagnosis of GBM should be performed early, even if dogs are not clinically ill. In other words, cut them before they become clinical!

Some limitations that you need to be aware of with this study? First, it’s retrospective in nature, and there is lack of randomization or a control population when assessing treatment protocols. Also, there is lack of long-term follow up in this study. We only know if these patients survived until hospital discharge, not if they had recurrent issues or re-hospitalization in the short term post-op period. Some comparisons also may have had low statistical power due to the retrospective nature of the medical record review and lack of some information being available.

Regardless, there are a few takeaways from this VETgirl podcast. Dogs that were healthier prior to cholecystectomy had a significantly lower mortality rate than dogs that were already sick at the time of surgery. Early surgical intervention is recommended for patients with ultrasonographic evidence of a GBM to improve outcome. The mortality rate reported here in both elective (2%) and non-elective (20%) cholecystectomy patients is lower than previously reported, which may help counsel owners pre-operatively.

References:
1: Mehler SJ. Complications of the extrahepatic biliary surgery in companion animals. Vet Clin North Am Small Anim Pract 2011;41:949–967.
2. Pike FS, Berg J, King NW, et al. Gallbladder mucocele in dogs: 30 cases (2000–2002). J Am Vet Med Assoc 2004;224:1615–1622.
3. Malek S, Sinclair E, Hosgood G, et al. Clinical findings and prognostic factors for dogs undergoing cholecystectomy for gallbladder mucocele. Vet Surg 2013;42:418–426.
4. Worley DR, Hottinger HA, Lawrence HJ. Surgical management of gallbladder mucoceles in dogs: 22 cases (1999–2003). J Am Vet Med Assoc 2004;225:1418–1422.
5. Besso JG, Wrigley RH, Gliatto JM, et al. Ultrasonographic appearance and clinical findings in 14 dogs with gallbladder mucocele. Vet Radiol Ultrasound 2000;41:261–271.
6. Aguirre AL, Center SA, Randolph JF, et al. Gallbladder disease in Shetland Sheepdogs: 38 cases (1995–2005). J Am Vet Med Assoc 2007;231:79–88.
7. Choi J, Kim A, Keh A, et al. Comparison between ultrasonographic and clinical findings in 43 dogs with gallbladder mucoceles. Vet Radiol Ultrasound 2014;55:202–207.
8. Youn G, Waschak MJ, Kunkel KAR, Gerard PD. Outcome of elective cholecystectomy for the treatment of gallbladder disease in dogs. J Am Vet Med Assoc 2018;252:970–975

  1. Bryan Park says:

    I see a lot patients that present themselves with lethargy, anorexia, and vomiting that have high ALP levels, occasional high GGT and ALT levels. No real signs of Cushings. I usually place them on Denamarin and Ursodiol and hope for the the best in 2-3 weeks. Is it really necessary to refer these patients for ab ultrasounds and possible cholecystectomies? I saw a case of this during an externship and this patient was not doing well. Hence my choice of treatment.

    • VETgirl says:

      My concern is why the meds if you don’t know what the etiology is? Typically, warrants a work up to rule out neoplasia, mucocele, etc.

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