Serum amyloid A and plasma fibrinogen concentrations in horses following emergency exploratory celiotomy

Abstract

Summary Background Acute‐phase proteins may help assess the nature and severity of lesions and outcome in horses undergoing colic surgery. Objectives To compare serum amyloid A and plasma fibrinogen concentrations ([SAA] and [fibrinogen]) in the immediate post‐operative period after exploratory celiotomy and determine their value in assessment of post‐operative complications and survival to discharge. Study design Observational study. Methods This study included horses over 1 year of age undergoing exploratory celiotomy. Surgical procedures, lesions, post‐operative care, complications and survival to discharge were recorded. [SAA] and [fibrinogen] were measured prior to surgery and 5 days post‐operatively. Statistical analyses included Yate's Chi‐square test, linear mixed effects model, Mann–Whitney U test and logistic regression. Results Of 300 horses, 52.0% developed post‐operative complications and 83.7% survived to discharge, with significantly reduced chance of survival in horses that developed post‐operative complications (P<0.01). Median [SAA] at days 1, 2, 3, 4 and 5 and median [fibrinogen] at days 3, 4 and 5 were significantly different between horses that did and did not develop post‐operative complications (P<0.05). Median [SAA] at days 1, 4 and 5 were significantly different between horses that did and did not survive to discharge (P<0.05). Logistic regression revealed post‐operative complications to be associated with strangulating lesions (OR 2.35, 95% confidence interval [CI] 1.41–3.91, P≤0.001) and higher [fibrinogen] at admission (OR 1.21, 95% CI 1.00–1.45, P<0.05), and survival to discharge to be associated with lower [SAA] at 5 days post‐operatively (OR 0.965, 95% CI 0.94–0.99, P = 0.002). Main limitations A large variety of lesions and complications prevented detailed analysis of associations between inflammatory markers, lesions and complications. Conclusions Horses that develop post‐operative complications have acute‐phase responses of greater magnitudes and durations compared with those that do not develop complications. This is also seen in horses that do not survive to discharge. Measuring [SAA] daily and [fibrinogen] at admission, may help predict the development of post‐operative complications.

Clinical insights: Update on colic

“…Serum amyloid A (SAA) has been examined in several papers to aid in the diagnosis of post‐operative colic complications. A new study examining SAA following exploratory celiotomy in 300 horses corroborated previous findings that SAA and fibrinogen concentrations in post‐operative colic cases were found to peak at 2 and 4 days post‐operatively respectively 15 . This study showed that SAA was elevated in horses with complications in the post‐operative period but that only SAA on day 5 could be used as a predictor of survival.…”

Equine Inflammatory Markers in the Twenty-First Century

“…47 It is known that surgery itself, such as exploratory celiotomy for colic, causes an increase in APPs, including SAA. 43,[48][49][50] Compared with more minor surgical procedures, exploratory celiotomy causes a prolonged APR, with serum SAA concentrations increased from 48 to 96 hours after surgery (compared with 12-24 hours with minor procedures). 48,50,51 Horses with postoperative complications had a more pronounced increase in SAA (61.4-fold over baseline) and took longer to achieve peak values (96 hours) compared with horses without complications (29fold increase; peak at 48 hours).…”

“…43,[48][49][50] Compared with more minor surgical procedures, exploratory celiotomy causes a prolonged APR, with serum SAA concentrations increased from 48 to 96 hours after surgery (compared with 12-24 hours with minor procedures). 48,50,51 Horses with postoperative complications had a more pronounced increase in SAA (61.4-fold over baseline) and took longer to achieve peak values (96 hours) compared with horses without complications (29fold increase; peak at 48 hours). 50 Another prospective study assessing SAA and complications in postoperative colic patients found that the magnitude of SAA increase was greater at 48 hours and 4 to 6 days postsurgery in horses with versus those without complications.…”

“…48,50,51 Horses with postoperative complications had a more pronounced increase in SAA (61.4-fold over baseline) and took longer to achieve peak values (96 hours) compared with horses without complications (29fold increase; peak at 48 hours). 50 Another prospective study assessing SAA and complications in postoperative colic patients found that the magnitude of SAA increase was greater at 48 hours and 4 to 6 days postsurgery in horses with versus those without complications. 49 The data are conflicting regarding the accuracy and utility of SAA for determining outcome and prognosis in horses with colic.…”

Highlights of recent clinically relevant papers

“…This study by Michael De Cozar and colleagues in the UK aimed to compare serum amyloid A ([SAA]) and plasma fibrinogen ([fibrinogen]) concentrations in the immediate post‐operative period in horses undergoing exploratory celiotomy for colic unresponsive to medical management .…”