Colic Surgery Complications
Colic surgery is meant to help horses in distress, but complications following the procedure—such as incisional infections, postoperative ileus (lack of gut motility), or thrombophlebitis (blood vessel inflammation and blockage)—can put the patient back into a precarious, even life-threatening, position. Treating complications early can help improve outcomes, but it’s not always easy to tell which horses are most at risk for developing problems.

At the 2017 International Equine Colic Research Symposium, held July 18-20 in Lexington, Kentucky, Michael De Cozar, BSc(Hons), BVetMed, MRCVS, shared the results of a study in which he and colleagues evaluated whether two easily measurable biomarkers in horses’ blood—serum amyloid A (SAA) and plasma fibrinogen concentrations—could help predict colic surgery complications. De Cozar is a surgery resident at Bell Equine Veterinary Clinic, in Kent, England.

Serum amyloid A is a protein produced in response to an inflammatory insult. Importantly for veterinarians, its concentrations increases and decreases rapidly, allowing them real-time information on inflammation via a blood test. Fibrinogen is also an inflammatory marker, but doesn’t change quite as quickly as SAA.

In their prospective study, the researchers measured SAA and fibrinogen concentrations in horses undergoing exploratory laparotomy or celiotomy (abdominal surgery) at admission and again every 24 hours for five days following surgery.

Their study population included 275 horses—165 geldings, 102 mares, and eight stallions—ranging in age from 2 to 31 years. Less than half the horses (125/275, 45.5%) developed postoperative complications.

De Cozar said SAA concentrations peaked on Day 3 and Day 4 following surgery in horses without and with complications, respectively. Additionally, SAA concentrations were significantly higher in horses that developed complications on Days 2, 3, 4, and 5.

Meanwhile, fibrinogen concentrations peaked on Day 4 in horses without complications, but continued to increase on Day 5 in horses that developed complications. Also on Day 5, fibrinogen concentrations were significantly higher in horses with complications.

De Cozar said these results suggest that horses’ acute inflammatory responses are prolonged following colic surgery and peak three to four days following celiotomy. Thus, if inflammatory markers continue to increase post Day 3-4, veterinarians could suspect an underlying complication.

“The use of inflammatory markers may be helpful to detect postoperative complications,” he said. “Further studies are warranted to explore these associations.”

Still, De Cozar said veterinarians can begin monitoring SAA and fibrinogen levels following surgery, “especially monitoring SAA trends over the first few days after exploratory laparotomy to catch possible complications early.”