Peritoneal D-dimer concentration for assessing peritoneal fibrinolytic activity in horses with colic

Background: Plasma D-dimer concentration is a useful marker to assess systemic coagulation and fibrinolytic activities in humans, dogs, and horses. Peritoneal fibrinolytic activity increases in horses with colic, especially in horses with endotoxin in the peritoneal fluid. Hypothesis/Objectives: Peritoneal D-dimer concentration can be used to assess peritoneal fibrinolytic activity in horses with severe gastrointestinal (GI) disorders and altered peritoneal fluid. Animals: Two hundred and twenty-one colic horses and 15 control horses. Methods: Prospective observational clinical study. Blood and peritoneal fluid were collected on admission. Horses were grouped according to diagnosis, peritoneal fluid analysis, and outcome. Peritoneal D-dimer concentration was determined, together with peritoneal tissue-plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) activities. Plasma D-dimer concentration also was measured. Results: Peritoneal D-dimer concentration was significantly higher in all colic groups compared with controls, and in horses with enteritis, peritonitis, and ischemic disorders compared with horses with large intestinal obstructions. Peritoneal D-dimer concentration was significantly higher in horses with altered peritoneal fluid (modified transudate and exudate) compared with horses with normal peritoneal fluid analysis. Plasma D-dimer concentration also was significantly higher in the peritonitis group, and in horses with altered peritoneal fluid analysis. Peritoneal and plasma D-dimer concentrations also were significantly higher in nonsurvivors. Peritoneal D-dimer concentration was significantly correlated with decreased peritoneal t-PA activity and increased peritoneal PAI-1 activity. Conclusions and Clinical Importance: Peritoneal D-dimer concentration is markedly higher in severe GI disorders, and it can be used to assess peritoneal fibrinolytic activity in horses with colic. © 2009 by the American College of Veterinary Internal Medicine.