ISRAEL JOURNAL OF
VETERINARY MEDICINE
ANALYSIS OF HEMOSTASIS IN HORSES WITH
COLIC
Vol. 57 (2)
2002
Z. Y•lmaz1
1
and Y. Il‫חצ‬l2
1. Dept.of Internal Medicine, Veterinary Faculty, Uludag University,
Bursa-Turkey
2. Laboratory of Biochemistry, Medicine Faculty, Uludag University,
Bursa-Turkey
Abstract
Hemostatic profiles were measured in 23 horses with naturally acquired colic and in 10
healthy horses. Blood samples were taken from each horse to evaluate a minimal
hemostatic profile including prothrombin time (PT), activated partial thromboplastin time
(aPTT), fibrinogen, fibrinogen degradation products (FDPs), antithrombin III (AT III) activity
and platelet count. The test group included 23 horse with colic, which were divided into 3
groups based on its severity: T1 (mild colic), T2 (moderate colic) and T3 (severe colic).
Ten adult healthy horses served as controls.
The causes of colic were recognised as a simple obstruction (n=14), small intestinal
volvulus (n=1), strangulation obstruction (n=1) and non-definitive diagnosis (n=7). PT
(p<0.05), aPTT (p<0.01), and FDPs (p<0.001) increased but platelet count (p<0.001)
decreased in the test group compared with the control group. In the test groups, AT III
activity in T3 group was lower than in T1 and T2 groups (p<0.001). In the T3 group, 2
horses that had decreased AT III activity and increased FDPs (p<0.001) died from small
intestinal volvulus and strangulation obstruction, diagnosed at post mortem.
It was concluded that hemostatic profiles (PT, aPTT, fibrinogen, AT III, FDPs and platelet
count) were changed in horses with colic.
Introduction
Introduction
Hemostasis is a complex process with positive and negative regulators for formation and
degradation of fibrin. Imbalanced regulation may lead to hypercoagulation (thrombosis),
hypocoagulation (hemorrhage), or paradoxically to both of them, in disseminated
intravascular coagulation (DIC) (1,2,3,4,5). Hemostatic abnormalities such as
thrombocytopenia, prolonged clotting times, increased fibrinogen degradation products,
decreased fibrinogen and decreased antithrombin III activity have been reported in horses
with colic (1,5,6,7,8,9).
Minimum laboratory data needed to evaluate hemostasis in large animals include a
platelet count, plasma fibrinogen, the prothrombin time (PT), activated partial
thromboplastin (aPTT) and fibrin/fibrinogen degradation products (FDPs) (2,3,5,10,11).
Primary hemostasis can be evaluated by determination of platelet numbers, secondary
hemostasis can be evaluated by the activated partial thromboplastin (aPTT) for intrinsic
and common pathway abnormalities, fibrinogen quantification (common pathway
abnormalities), and prothrombin time (PT) for extrinsic and common pathway
abnormalities. The presence of fibrin degradation products (FDPs) suggests active
systemic fibrinolysis (2,3). Antithrombin III (AT III), a regulator of thrombin and other
procoagulant enzymes, has significantly increased activity in surviving compared with
nonsurviving horses with colic (1,6,7,9,11,12,13,14,15,16). DIC is manifested by multiple
hemostatic abnormalities, and serial analysis reveal reduced platelet numbers and a trend
towards prolongation of the PT, aPTT, and TT (Thrombini time), with reduction in plasma
AT III. FDPs are most often elevated by DIC as well. The combination of
thrombocytopenia with the mild-to-moderate prolongation of the PT and/or aPTT strongly
suggest DIC (1,3,14,15,16,17,18).
The most common forms of hemostatic dysfunction in large animals are DIC, consumption
coagulopathy, defibrination syndrome, or intravascular coagulation fibrinolysis (3,4). In
large animals DIC has been described in association with forms of localized and/or
systemic septic processes, neoplasia, gastrointestinal disorders (e.g., strangulating
intestinal obstruction, acute enteritis) and renal diseases (4). Diffuse activation of the
hemostatic system is particularly prevalent in horses with acute gastrointestinal disorders
(7,8,13). Microvascular thrombosis and subsequent ischemia to vital tissues leads to
organ malfunction such as renal failure, which contributes to the morbidity and mortality of
the primary diseases process (19). Acute tubular necrosis following renal involvement
poses a serious threat to life. Gastrointestinal microthrombosis may induce colic as a
result of submucosal necrosis (3,4,5).
The purpose of this study was to determine the abnormalities of hemostatic profiles in
horses with colic.
Materials and Methods
This study included 23 adult horses that were admitted to the breeding farm of the Military
Veterinary Teaching Hospital with signs of colic, of both sexs (9 male and 14 female) and
age (2-6 years). Ten healthy adult horses of both sexes (5 male and 5 female), aged from
2 to 6 years, served as controls from the same population. Horses with colic were
categorized as mild, moderate, and severe on the basis of compatible clinical and
laboratory findings of colic, such as tachycardia, prolonged capillary filling time, increased
PCV and total protein concentration, and abnormal mucous membranes (Table I). Of the
23 horses with colic, 11 had mild colic, 9 had moderate colic and 3 had severe colic.
Blood samples were collected from each horse in tubes containing 0.129 M sodium citrate
(Becton Dickinson Vacutainer) and EDTA. Plasma was immediately separated from blood
with sodium citrate and stored at -200C until evaluation of coagulation profiles. Platelet
counts were estimated by automatic haemocell counter (Serono Diagnostic) from blood
samples with EDTA. Coagulation profiles, included PT (Coagulation Factor II Deficient
Plasma OSGR 13-3x1ml, DADE Behring, Germany), aPTT (Actin® aPTT B4218-1 10x2ml,
DADE Behring, Germany), fibrinogen (Multifibren® U OWZG 15-14x2ml, DADE Behring,
Germany), FDP (D-Dimer) (Dimertest® latex Assay B4233-60, DADE Behring, Germany)
and AT III (Berichrom® Antithrombin III OUBP 21, DADE Behring, Germany) were
performed using an automatic analyser (Behring Coagulation Timer) in the laboratory of
biochemistry of the Medical Faculty, University of Uludag.
Table-I: Clasification of cases with colic based on clinical and laboratory findings
Parameters
Mild Colic
Moderate Colic
Severe Colic
n=11
n=9
n=3
Pulsation /min
40-60
60-80
>80
Capillary Filling
Time sc
1-2
2-3
>3
Mucous membrans
Normal- hyperemic
(+)
Hyperemic (++)
Hyperemic (+++)
Hematocrit %
30-45
45-60
>60
Total protein gr/dl
6-8
8-10
>10
Statistical Analysis
All data were analysed by use of Student-t test. In horses with colic, mild versus severe
colic data for each variable determined on the sample collection were compared using
one-factor analysis of variance. Results were considered significant at p<0.05.
Results
Outcome: The causes of colic in 23 horses are presented in Table II. Two horses died in
the T3 group because of small intestinal volvulus and strangulation obstruction, diagnosed
on post mortem. The rest of horses were treated medically.
Table II: The causes of colic in test groups
The causes of colic
n
T1
T2
T3
Simple obstruction
14
8
6
-
Strangulation obstruction
9
3
3
3*
TOTAL
23
11
9
3
* Two horses died
T1: mild colic T2: moderate colic T3: severe colic
Coagulation Profiles: Table III presents the coagulation test results. As seen in Table III;
PT (p<0.05), aPTT (p<0.01), and FDPs (p<0.001) increased but platelet count (p<0.001)
decreased in the test group compared with the control group. The increase of fibrinogen
concentration and decrease in AT III activity were not significant in the test group.
Table III: The comparison of coagulation parameters between control and test groups.
Control Group
Test Group
Mean±SD
Mean±SD
n=10
n=23
276.2±94.1
141.4±41.3***
100-600x103/mm3
8.3±1.9
13.1±2.6*
<7-9sc
44.3±10.1
88.7±26.3**
37-54sc
Fibrinogen gr/dl
0.3±0.1
0.4±0.2
0.2-0.4 gr/dl
Fibrin split products µg/ml
6.5±2.7
18.6±11.3***
<32 µg/ml
Parameters
Platelet Count x103/mm3
Prothrombin time /sc
Activated partial thromboplastin time
/sc
Reference
Value(3)
Anti-thrombin III %
116.3±12.1
91.6.0±24.2
84-118%(20)
*p<0.05 **p<0.01 ***P<0.001
Table IV: Coagulation test result in T1 (mild colic), T2 (modarate colic) and T3 (severe colic)
groups.
T1
T2
T3
Mean±SD
Mean±SD
Mean±SD
n=11
n=9
n=3
152.0±43.4
144.7±38.3
98.3±2.8
Prothrombin time /sc
11.6±0.8a
13.5±3.4ab
18.3±1.0b**
Activated partial thromboplastin time /sc
69.8±8.3a
81.2±7.0ab
124.7±14.6b**
Fibrinogen gr/dl
0.4±0.1a
0.6±0.1b
0.1±0.1c***
Fibrin split products µg/ml
12.3±4.2a
14.4±6.6ab
38.8±9.7b***
Anti-thrombin III %
98.3±6.5a
94.1±8.5ab
70.3±5.4b***
Parameters
Platelet Count x103/mm3
*p<0.05 **p<0.01 ***p<0.001
a, b, c: difference letter on the same line are found to be important
Discussion
In this study, hemostatic profiles were determined in 23 horses with colic and in 10 healthy
horses from a breeding population. Abnormalities of hemostasis such as
thrombocytopenia, prolonged clotting times, increased fibrinogen degradation products,
decreased fibrinogen and decreased antithrombin III activity have been reported in horses
with colic (1,2,6,7,8,9,11,12,14,16,17). The minimum laboratory database needed to
evaluate hemostasis in large animals includes platelet count, plasma fibrinogen,
prothrombin time (PT), activated partial thromboplastin (aPTT) and fibrin/fibrinogen
degradation products (FDPs) (3).In our study, these tests were performed and prolonged
prothrombin time (p<0.05) and activated partial thromboplastin time (p<0.01), increased
fibrin degragation products (p<0.001), and decreased platelet counts (p<0.001) were
observed in the test group compared with the control group. The possible explanation of
altered hemostasis may be related to endotoxin absorption from the intestines in this
study, as in agreement with other studies (5,8,10,12). This may be supported by a study in
which 9 horses had detectable endotoxin in their plasma out of 30 horses with colic (12).
Barton et al. (18) reported that during endotoxemic shock, the delicate balance of
procoagulant, anticoagulant, and fibrinolytic factors that maintains homeostasis of the
coagulation system is disrupted. Increased FDPs concentration is indicative of increased
activation of coagulation, and prolonged PT is indicative of coagulation factor consumption
(12).
Clinical and laboratory findings as well as coagulation profiles change on the basis of
severity of colic in horses (1,2,3,6,7,8,12,13,16). Boom and Velden (19) reported that
strangulating obstructions of the small intestine still carry a poor to guarded prognosis, and
mortality was highest in the direct pre-operative period. Similarly, two horses with
strangulating obstructions died in the study. All horses with colic were divided into 3
groups and coagulation test results were evaluated. Within test groups, the platelet count
was decreased, in T1 and T2 groups, but in T3 group was not statistically significant. This
might be attributed to the release of endogenous mediators such as platelet activating
factor in inflammatory disorders. Also antithrombin III (AT III) activity was determined and
was low in the test group. The alteration of hemostatic tests in this study may be an
indicator of active coagulation and fibrinolysis. It has been reported that prolonged PT was
the most frequently observed abnormality in the coagulation profile and was more likely to
be prolonged in horses with colic that did not survive (10,11,12). These changes were in
agreement with our study, determined a prolonged PT and aPTT (p<0.01) in T3 group.
Small intestinal volvulus and strangulation obstruction were diagnosed based on postmortem examination of the non-surviving horses in T3 group, in which in addition to these
test results, AT III activity and fibrinogen concentrations were lower than those in T1 and
T2 group (P<0.001).
Many of the significant differences (decreased AT III, decreased fibrinogen, increased PT,
aPTT, and FDPs concentration) were thought to be related to DIC in the T3 group. Low AT
III activity is also associated with poor prognosis (12). Darien et al. (13) observed that AT
III activity in colic (55-76%) was significantlydifferent from the reference value for healthy
adults (92-102%) and also the mean AT III activity of the survivor was significantly greater
than that of the nonsurvivor. AT III is a major inhibitor of thrombin and other serine
proteases of the coagulation system (1). For this reason, decreased AT III activity (70%) in
our study might be considered as a principal marker for DIC in T3 group. This
consideration may be supported by decreased fibrinogen concentration in this group
(p<0.001). The longer clotting time (PT, aPTT) in the test group may have been the result
of decreased coagulation factors. This may be related to consumption coagulopathy of
coagulotion factors (5,18). As noticed in other studies (14,16), fibrinogen concentrations
increased (p<0.001)in all horses of T1 and T2 groups, regardless of diagnostic category,
while it decreased in T3 group. This may be related to an acute phase reaction in T1 and
T2 groups. Likewise, Topper and Prasse (17) reported that an increased fibrinogen
concentration was an acute phase response that contributes to changes observed in
coagulation proteins in horses with colic. Prasse et al. (1) reported that in experimentally
induced and naturally developing inflammation in horses, proteins considered as part of
the acute phase response include haptoglobulin, transferrin, ferritin, ceruloplasmin,
fibrinogen and c-reactive protein. Otherwise, a decrease in fibrinogen concentration in T3
group is more likely related to stimulated fibrinolytic activity. Although FDPs concentration
increased in all horses with colic, it was within normal limits. As with decreased AT III
activity and prolonged PT and aPTT, these changes were most dramatic in horses in T3
group, due to the severity of colic.
As a result, it is concluded that hemostatic profiles (PT, aPTT, fibrinogen, AT III, FDPs and
platelet count) could change with the severity of the colic in horses.
References
1.
1. Prasse, K.W., Topper, M.J., Moore, J.N. and Welles, E.G.: Analysis of hemostasis in
horses with colic. J.A.V.M.A., 203(5): 685-693, 1993.
2. Petterson, J.L., Couto, C.G. and Wellman, M.L.: Hemostatic disorder in cats: A
retrospective study and review of the literature. J. Vet. Inten. Med., 9(5): 298-303, 1995.
3. Morris, D.D.: Alterations in the clotting profile. In: Smith B.P. (Ed.): Large Animal
Internal Medicine, The C.V. Mosby Comp., Philadelphia, 445-451, 1990.
4. Byars, T.D.: Disseminated intravascular coagulation. In: Robinson, N. E. (Ed.): Current
Therapy In Equine Medicine. W.B. Saunders Comp., Philadelphia, 306-309, 1987.
5. Weiss, D.J. and Rashid, J.: The sepsis-coagulant axis: A review. J. Vet. Intern. Med.,
12: 317-324, 1998.
6. Collatos, C., Barton, M.H., Prasse, K.W. and Moore, J.N.: Intravascular and peritoneal
coagulation and fibrinolysis in horses with acute gastrointestinal diseases. J.A.V.M.A.,
207(4): 465-470, 1995.
7. Collatos, C., Barton, M.H. and Moore, J.N.: Fibrinolytic activity in plasma from horses
with gastrointestinal diseases: changes associated with diagnosis, surgery, and outcome.
J. Vet. Intern. Med., 9(1): 18-23, 1995.
8. Sandholm, M., Vidovic, A., Pouteran, R.A., Sankari, S., Nyholm, K. and Rita, H.:
D-Dimer improves the prognostic value of combined clinical and laboratory data in
equine gastrointestinal colic. Acta Veterinaria Scan., 36(2): 255-272, 1995.
9. Monreal, L., Angles, A., Espada, Y., Monesterio, J. and Monreal, M.:
Hypercoagulation and hypofibrinolysis in horses with colic and DIC. Equine Vet. J.
(Suppl.), 32: 19-25, 2000.
10. Michelle, M.H. and Moore, J.N.: Whole blood re-calcification time in equine
colic. Equine Vet. J., 23(4): 303-308, 1991.
11. Welch, R.D., Watkins, J.P., Taylor, T.S., Coren, N.D. and Carter, G.K.:
Disseminated intravascular coagulation associated with colic in 23 horses (19841989). J. Vet. Intern. Med., 6(1): 29-35, 1992.
12. Henry, M.M. and Moore, J.N.: Clinical relevance of monocyte procoagulant
activity in horses with colic. J.A.V.M.A., 198(5): 843-848, 1991.
13. Darien, B.J., Potempa, J., Moore, J.N. and Trav•s, J.: Antithrombin III activity
in horses with colic: an analysis of 46 cases. Equine Vet. J., 23(3): 211-214, 1991.
14. Johonstone, I.B. and Cdane, S.: Hemostatic abnormalities in equine colic. Am.
J. Vet. Res., 47(2): 356-358, 1986.
15. Topper, M.J. and Prasse, K.W.: Use of immunosorbet assay to measure
thrombin-antithrombin III complexis in horses with colic. Am. J. Vet. Res., 57(4):
456-562, 1996.
16. Parry, B.W.: Use of clinical pathology in evaluation of horses with colic. Vet.
Clin. North Am. Equine Pract., 3(3): 529-542, 1987.
17. Topper, M.J. and Prasse, K.W.: Analysis of coagulation proteins as acutephase reactants in horses with colic. Am. J. Vet. Res., 59(5): 542-545, 1998.
18. Barton, M.H., Morris, D.D., Norton, N. And Prasse, K.W.: Hemostatic and
fibrinolytic indices in neonatal foals with presumed septicemia. J. Vet. Intern.
Med., 12: 26-35, 1998.
VRa Red vdVmn -d . n a-nd .R Ann , e. d . ed .Ra nR .R , o.B.n d naV .91
nl vaambd VaRdV R V nl Vad av dVm a nc VavbVmn nl V R
d m VR Vm R m na R n
wee9. ,91-nRV. 3vdaV. wQuQ n9e1 .d aRemR2 nl wwe bd R
Ra da. , d.n B VmV an cm RRR .RVRa m dVmn m na R . eRlRaR bR ed vR d . dbdvmaR. .we
‫ה‬d VmV an cm RRR .RlmbmR bh. tmarztl. Prax. 15(1): 47-55, 1987.