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Heparin resistance in patients with coronary artery disease
Atherosclerosis, 18 (1973) 509-512 0 Elsevier Scientific Publishing Company, Amsterdam
509 - Printed in The Netherlands
Letter to the Editors
HEPARIN DISEASE
RESISTANCE
IN PATIENTS
WITH CORONARY
ARTERY
In a paper recently published in your Journal Korsan-Bengtsen et a1.l reported finding a significantly shortened recalcification time, a shortened partial thromboplastin time in siliconized tubes, and a significantly decreased F II-VII-X-activity in 83 patients, 3 months after their first myocardial infarction. The other parameters they studied did not show any significant changes. In previous experiments we also studied recalcification time (RT) in patients with severe atherosclerosis and our results were similar to those of Korsan-Bengtsen et af.l. The difference in RT between normal and atherosclerotic subjects became still more apparent after intravenous injection of 2500 U heparin; the atherosclerotic group showed a definite resistance to the drugs. To investigate the matter further, we studied heparin clotting time and heparin thrombin timesy4 in patients with myocardial infarction and other forms of coronary artery disease (CAD). These tests are variants of the heparin tolerance test in vitro5, the first being RT with the addition of 0.7 U heparin in calcium chloride, the second being thrombin clotting time with 3 different concentrations of heparin (0.3, 0.5 and 0.7 U). We performed these tests on the lst, 2nd, 3rd, 8th, 15th, 22nd and 90th day after infarction and, in other forms of CAD at a similar interval after admission. The results were compared with those of normal volunteers in their late teens and early twenties. Heparin clotting time was significantly shorter in both pathologic groups than in the normal; this could be seen throughout the follow-up and also when all results of the pathologic groups were taken in bulk. As these results were consistent throughout the follow-up, we omit to show in the table the results on individual days and show the bulk results of the whole groups only (Table 1, Part A). Heparin thrombin time did not show much difference between the different groups in absolute time values at the concentrations of 0.3 and 0.5 U of heparin throughout the follow-up, although in the evaluation of the whole groups a significant difference appeared with 0.5 U heparin. However, with the concentration of 0.7 U heparin a significant difference in the sense of “hypercoagulation” could be seen in both pathologic groups compared with the normal in absolute time values on all days. When comparing the responses to heparin, i.e. comparing the time prolongation
LETTER TO THE EDITORS
510 TABLE
1
HEPARIN
CLOTTING
TIME:
Group
(4
(B)
COMPARISON
0 Age
BETWEEN
n examinations
CONTROL,
0 min.
INFARCT
AND
SD
CAD
GROUPS
Significance t control vs. path.
P <
Control
20.37
53
7.78
1.34
-
-
Infarct CAD
56.88 55.12
117 78
6.43 6.56
0.85 0.69
= 6.733 = 6.100
0.0005 0.0005
Control
50.45
22
7.25
0.96
-
-
Infarct CAD
59.60 62.93
20 19
6.10 6.13
0.21 0.25
= 5.481 = 5.221
o.OOO5 o.OOO5
(A) Young control group. (B) Middle-aged control group.
TABLE
2
HEPARIN
THROMBIN
TIME:
Group
(A)
Control n = 52 0 set SD
COMPARISON
BETWEEN
CONTROL,
INFARCT
AND
CAD
GROUPS
Heparin concentration
Difference
( %)
Significance
l/0.3
310.7 U
A I:2
Al:3
t control vs.path. P <
44.9 5.94
+ 37.88 14.44
+ 110.95 26.39
21.37 2.19
U 2jO.5 u
29.4 3.96
!
Infarct
n = 109 0 set 21.41 SD 2.36
= 0.5 0.3 = 2.887 0.107 0.475 0.0025 i A 0.7 1:2 = 3.906 5.871 OOOO5 0.0005
\
27.59 3.18
39 5.99
+ 29.18 10.18
+
82.90 25.66
A 1:3 = 6.363 OOOO5 ’ CAD
(B)
n=78 0 set SD
Control n = 22 0 set SD Infarct
n = 20 0 set SD
21.41 2.41
27.60 3.67
38.96 5.98
+ 29.05 13.60
+
83.01 27.84
16.77 2.47
22.14 3.75
38 6.44
+ 31.98 9.85
+ 127.17 26.94
15.3 2.03
20.25 3.23
28.95 4.67
+ 30.78 11.19
+
( 0.5 0.3 = 2.626 0.504 !’A A 0.7 1:2 = 5.563 3.496
0.005 0.35 OOOO5
1:3 5.785
o.OOO5
0.5 0.3 = 2.100 1.755 =
0.05 0.025
i 89.74 23.33
( A 0.7 1:3 = 0.367 1:2 4.824 5.241 i 0.5 0.3 = 0.996 0.986 CAD
n=19 0sec SD
16 2.49
21 3.57
(A) Young control group. (B) Middle-aged control group. For 0 age compare with Table 1.
32.37 6.77
+ 31.15 8.46
+ 102.16 28.95
0.7 = 2.716 A 1:2 = 0.290 A 1:3 = 2.848
O.OOO5 0.005 0.40 0.20 0.005 0.40 0.005
511
LETTER TO THE EDITORS
with increasing heparin concentrations, this was markedly lower in the pathologic groups than in the control one. The nature of the results entitles us again to present them in a shortened table showing summarised results of the whole groups only (Table 2, Part A). Later, on the advice of the editor, we repeated our study in an abridged form using a middle-aged control group, in order to avoid the possible misinterpretations due to the considerable age difference between control and pathologic groups. As can be seen from parts B of Tables 1 and 2 the results were similar to those of the previous series with the young control group: however, some slight difference in the degree of significance of the response to heparin in heparin thrombin time could indicate some dependence on age. Tn our previous experiments we found shortened RT together with increased resistance to heparin. Therefore, we think that it is justifiable to point out this coincidence, and that Korsan-Bengtsen’s results and ours point in the same direction: in atherosclerotic patients the equilibrium in clotting regulating mechanisms is disturbed one way or the other. TABLE
3
CLOTTING
ACTION
OF FRESH
Group
(A)
CAD
(B)
CAD
300 Illg/lOO IllI SOLUTION
OF FIBRINOGEN
Significance
I:9
I:3
I:1
3:l
t control vs.path.
152.65 51
72.55 31.35
46.90 21.64
29.40 15.12
-
n = 30/32 0 set 114.25 SD 52.79
55.81 26.11
35.28 17.57
21.97 10.86
n=25 0 set SD
119.64 46.55
55.88 21.31
36.76 14.82
23.88 9.65
122.24 21.21
57.67 11.91
31.10 6.88
20 4.17
Control n = 21 0 set SD Infarct
ON A
Dilutions of the serum
Control n = 20 0 set SD Infarct
SERUM
n = 20 0 set SD
86.3 17.31
44.7 10.39
26.65 5.4
19.15 4.07
n=l7 0 set SD
90.45 19.13
48 9.21
30.88 7.43
20.41 4.46
(A) Young control group. (B) Middle-aged control group.
1.995 i 1:3 1:9 = 2.571 1:;:
:
:.;;:
2.032 i 1:9 1:3 = 21242
‘1.9 = 5957 r, = 3’721 ’ I 1 :l = 2:310 t3:1 0.660 2.822 i 1:3 1:9 = 4.848 1:l = 0.094 3:l = 0.290
P -<
0.01 0.05 0.025 0.05 0.025 0.025 0.05 0.1
o.OOO5 0.0005 0.025 0.30 0.0005 0.005 0.475 0.40
512
LETTER TO THE EDITORS
The increased resistance to heparin, which is prevalently thought to exert an antithrombin activity, would suggest that there is an increased “availability” of thrombin in patients with CAD. Such increased thrombin might originate in a possible activation of intravascular microcoagulation mechanisms. Following this reasoning, we tried to assess thrombin activity in fresh serum, which was used 2 min after titrated platelet-poor plasma had been clotted by recalcification. The serum thus obtained was added to an 0.3 % solution of fibrinogen in saline. The serum was diluted before use with saline (1:9, 1:3, 1 :l and 3:l by vol.) in order to avoid lack of sensitivity in undiluted serum; clotting times were measured after adding 0.1 ml of the serum to 0.1 ml of the fibrinogen solution. This investigation was also carried out in 2 series (as in Tables 1 and 2), with a young and a middle-aged control group. The results are shown in Table 3. The significantly shorter times in the pathologic groups suggest higher thrombin activity of the serum in patients with CAD compared with normal subjects, but without evidence of age-dependence. However, we propose to investigate this matter further. ACKNOWLEDGEMENT
This work has been supported by the Medical Research Council of New Zealand.
1 KORSAN-BENGTSEN, K., WILHELMSEN,L., ELMFELDT,D. AND TIBBLIN, G., Blood coagulation and fibrinolysis in man after myocardial infarction compared with a representative popuiation sample,
Atherosclerosis, 16 (1972) 83. 2 SVEHLA, C., Some findings on hypercoagulation mechanisms in relation to atherosclerosis, Rev. Czech. Med., 15 (1969) 65. 3 GORMSEN, J., A technique for the heparin tolerance test, Brit. J. Huemutol., 5 (1959) 257. 4 HOLGER-MADSEN,T., Heparin resistance in acute coronary occlusion measured by the plasma heparin thrombin time, Actu Huematol., 23 (1960) 195. 5 SOULIER,J. P. AND BOLLOCH, A. J., Le test de tolerance a I’heparine in vitro dans le controle du traitement par la dicoumarine, Presse m&d., 58 (1950) 1031. Southland Hospital Invercargill (New Zealand) (Revised, received July 18th, 1973)
c.
SVEHLA
509 - Printed in The Netherlands
Letter to the Editors
HEPARIN DISEASE
RESISTANCE
IN PATIENTS
WITH CORONARY
ARTERY
In a paper recently published in your Journal Korsan-Bengtsen et a1.l reported finding a significantly shortened recalcification time, a shortened partial thromboplastin time in siliconized tubes, and a significantly decreased F II-VII-X-activity in 83 patients, 3 months after their first myocardial infarction. The other parameters they studied did not show any significant changes. In previous experiments we also studied recalcification time (RT) in patients with severe atherosclerosis and our results were similar to those of Korsan-Bengtsen et af.l. The difference in RT between normal and atherosclerotic subjects became still more apparent after intravenous injection of 2500 U heparin; the atherosclerotic group showed a definite resistance to the drugs. To investigate the matter further, we studied heparin clotting time and heparin thrombin timesy4 in patients with myocardial infarction and other forms of coronary artery disease (CAD). These tests are variants of the heparin tolerance test in vitro5, the first being RT with the addition of 0.7 U heparin in calcium chloride, the second being thrombin clotting time with 3 different concentrations of heparin (0.3, 0.5 and 0.7 U). We performed these tests on the lst, 2nd, 3rd, 8th, 15th, 22nd and 90th day after infarction and, in other forms of CAD at a similar interval after admission. The results were compared with those of normal volunteers in their late teens and early twenties. Heparin clotting time was significantly shorter in both pathologic groups than in the normal; this could be seen throughout the follow-up and also when all results of the pathologic groups were taken in bulk. As these results were consistent throughout the follow-up, we omit to show in the table the results on individual days and show the bulk results of the whole groups only (Table 1, Part A). Heparin thrombin time did not show much difference between the different groups in absolute time values at the concentrations of 0.3 and 0.5 U of heparin throughout the follow-up, although in the evaluation of the whole groups a significant difference appeared with 0.5 U heparin. However, with the concentration of 0.7 U heparin a significant difference in the sense of “hypercoagulation” could be seen in both pathologic groups compared with the normal in absolute time values on all days. When comparing the responses to heparin, i.e. comparing the time prolongation
LETTER TO THE EDITORS
510 TABLE
1
HEPARIN
CLOTTING
TIME:
Group
(4
(B)
COMPARISON
0 Age
BETWEEN
n examinations
CONTROL,
0 min.
INFARCT
AND
SD
CAD
GROUPS
Significance t control vs. path.
P <
Control
20.37
53
7.78
1.34
-
-
Infarct CAD
56.88 55.12
117 78
6.43 6.56
0.85 0.69
= 6.733 = 6.100
0.0005 0.0005
Control
50.45
22
7.25
0.96
-
-
Infarct CAD
59.60 62.93
20 19
6.10 6.13
0.21 0.25
= 5.481 = 5.221
o.OOO5 o.OOO5
(A) Young control group. (B) Middle-aged control group.
TABLE
2
HEPARIN
THROMBIN
TIME:
Group
(A)
Control n = 52 0 set SD
COMPARISON
BETWEEN
CONTROL,
INFARCT
AND
CAD
GROUPS
Heparin concentration
Difference
( %)
Significance
l/0.3
310.7 U
A I:2
Al:3
t control vs.path. P <
44.9 5.94
+ 37.88 14.44
+ 110.95 26.39
21.37 2.19
U 2jO.5 u
29.4 3.96
!
Infarct
n = 109 0 set 21.41 SD 2.36
= 0.5 0.3 = 2.887 0.107 0.475 0.0025 i A 0.7 1:2 = 3.906 5.871 OOOO5 0.0005
\
27.59 3.18
39 5.99
+ 29.18 10.18
+
82.90 25.66
A 1:3 = 6.363 OOOO5 ’ CAD
(B)
n=78 0 set SD
Control n = 22 0 set SD Infarct
n = 20 0 set SD
21.41 2.41
27.60 3.67
38.96 5.98
+ 29.05 13.60
+
83.01 27.84
16.77 2.47
22.14 3.75
38 6.44
+ 31.98 9.85
+ 127.17 26.94
15.3 2.03
20.25 3.23
28.95 4.67
+ 30.78 11.19
+
( 0.5 0.3 = 2.626 0.504 !’A A 0.7 1:2 = 5.563 3.496
0.005 0.35 OOOO5
1:3 5.785
o.OOO5
0.5 0.3 = 2.100 1.755 =
0.05 0.025
i 89.74 23.33
( A 0.7 1:3 = 0.367 1:2 4.824 5.241 i 0.5 0.3 = 0.996 0.986 CAD
n=19 0sec SD
16 2.49
21 3.57
(A) Young control group. (B) Middle-aged control group. For 0 age compare with Table 1.
32.37 6.77
+ 31.15 8.46
+ 102.16 28.95
0.7 = 2.716 A 1:2 = 0.290 A 1:3 = 2.848
O.OOO5 0.005 0.40 0.20 0.005 0.40 0.005
511
LETTER TO THE EDITORS
with increasing heparin concentrations, this was markedly lower in the pathologic groups than in the control one. The nature of the results entitles us again to present them in a shortened table showing summarised results of the whole groups only (Table 2, Part A). Later, on the advice of the editor, we repeated our study in an abridged form using a middle-aged control group, in order to avoid the possible misinterpretations due to the considerable age difference between control and pathologic groups. As can be seen from parts B of Tables 1 and 2 the results were similar to those of the previous series with the young control group: however, some slight difference in the degree of significance of the response to heparin in heparin thrombin time could indicate some dependence on age. Tn our previous experiments we found shortened RT together with increased resistance to heparin. Therefore, we think that it is justifiable to point out this coincidence, and that Korsan-Bengtsen’s results and ours point in the same direction: in atherosclerotic patients the equilibrium in clotting regulating mechanisms is disturbed one way or the other. TABLE
3
CLOTTING
ACTION
OF FRESH
Group
(A)
CAD
(B)
CAD
300 Illg/lOO IllI SOLUTION
OF FIBRINOGEN
Significance
I:9
I:3
I:1
3:l
t control vs.path.
152.65 51
72.55 31.35
46.90 21.64
29.40 15.12
-
n = 30/32 0 set 114.25 SD 52.79
55.81 26.11
35.28 17.57
21.97 10.86
n=25 0 set SD
119.64 46.55
55.88 21.31
36.76 14.82
23.88 9.65
122.24 21.21
57.67 11.91
31.10 6.88
20 4.17
Control n = 21 0 set SD Infarct
ON A
Dilutions of the serum
Control n = 20 0 set SD Infarct
SERUM
n = 20 0 set SD
86.3 17.31
44.7 10.39
26.65 5.4
19.15 4.07
n=l7 0 set SD
90.45 19.13
48 9.21
30.88 7.43
20.41 4.46
(A) Young control group. (B) Middle-aged control group.
1.995 i 1:3 1:9 = 2.571 1:;:
:
:.;;:
2.032 i 1:9 1:3 = 21242
‘1.9 = 5957 r, = 3’721 ’ I 1 :l = 2:310 t3:1 0.660 2.822 i 1:3 1:9 = 4.848 1:l = 0.094 3:l = 0.290
P -<
0.01 0.05 0.025 0.05 0.025 0.025 0.05 0.1
o.OOO5 0.0005 0.025 0.30 0.0005 0.005 0.475 0.40
512
LETTER TO THE EDITORS
The increased resistance to heparin, which is prevalently thought to exert an antithrombin activity, would suggest that there is an increased “availability” of thrombin in patients with CAD. Such increased thrombin might originate in a possible activation of intravascular microcoagulation mechanisms. Following this reasoning, we tried to assess thrombin activity in fresh serum, which was used 2 min after titrated platelet-poor plasma had been clotted by recalcification. The serum thus obtained was added to an 0.3 % solution of fibrinogen in saline. The serum was diluted before use with saline (1:9, 1:3, 1 :l and 3:l by vol.) in order to avoid lack of sensitivity in undiluted serum; clotting times were measured after adding 0.1 ml of the serum to 0.1 ml of the fibrinogen solution. This investigation was also carried out in 2 series (as in Tables 1 and 2), with a young and a middle-aged control group. The results are shown in Table 3. The significantly shorter times in the pathologic groups suggest higher thrombin activity of the serum in patients with CAD compared with normal subjects, but without evidence of age-dependence. However, we propose to investigate this matter further. ACKNOWLEDGEMENT
This work has been supported by the Medical Research Council of New Zealand.
1 KORSAN-BENGTSEN, K., WILHELMSEN,L., ELMFELDT,D. AND TIBBLIN, G., Blood coagulation and fibrinolysis in man after myocardial infarction compared with a representative popuiation sample,
Atherosclerosis, 16 (1972) 83. 2 SVEHLA, C., Some findings on hypercoagulation mechanisms in relation to atherosclerosis, Rev. Czech. Med., 15 (1969) 65. 3 GORMSEN, J., A technique for the heparin tolerance test, Brit. J. Huemutol., 5 (1959) 257. 4 HOLGER-MADSEN,T., Heparin resistance in acute coronary occlusion measured by the plasma heparin thrombin time, Actu Huematol., 23 (1960) 195. 5 SOULIER,J. P. AND BOLLOCH, A. J., Le test de tolerance a I’heparine in vitro dans le controle du traitement par la dicoumarine, Presse m&d., 58 (1950) 1031. Southland Hospital Invercargill (New Zealand) (Revised, received July 18th, 1973)
c.
SVEHLA