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Platelet apheresis affects prothrombin time and plasminogen levels in healthy donors
Transfusion and Apheresis Science 33 (2005) 47–50 intl.elsevierhealth.com/journals/tras
Platelet apheresis affects prothrombin time and plasminogen levels in healthy donors Cengiz Beyan *, Ku¨rs‚at Kaptan, Serap Savas‚c¸ı, Ahmet Ifran, ¨ ztu¨rk, Birgu¨l O ¨ kmen Yes‚im O Department of Hematology, Gulhane Military Medical Academy, Etlik, 06010 Ankara, Turkey Received 21 September 2004; received in revised form 7 February 2005; accepted 13 February 2005
Abstract There are few studies evaluating whether platelet apheresis has an effect on hemostasis parameters or not. The aim of this study was to define the effects of platelet apheresis on hemostasis screening tests and plasminogen levels. The study was performed on 40 healthy donors. We compared the values obtained before and after apheresis and observed that the prothombin time (PT) elongated, plasminogen levels decreased and the activated partial thromboplastin and thrombin times were not changed significantly. The differences were not high enough to cause any hemostasis problem. It can be hypothesized that platelet apheresis affects PT and plasminogen levels in healthy donors. Ó 2005 Elsevier Ltd. All rights reserved.
1. Introduction Although platelet apheresis is frequently performed nowadays, there are few studies evaluating whether or not it has an effect on hemostasis parameters or not. Although many donors undergo repeated plateletpheresis, data on the consequences of plateletpheresis for the donorÕs health is scarce. * Corresponding author. Tel.: +90 312 304 41 01; fax: +90 312 304 41 00. E-mail addresses: [email protected], cbeyan@ yahoo.com (C. Beyan).
The aim of this study was to define the effects of platelet apheresis on hemostasis screening tests and plasminogen levels.
2. Materials and methods The study was carried on 40 healthy apheresis donors consisting of 36 men and four women whose mean age was 24.63 ± 6.22 years (range 20–46). Donors met the American Association of Blood Banks eligibility criteria for plateletpheresis donation and gave informed consent for participation in the study. Platelet apheresis was the first
1473-0502/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.transci.2005.02.003
48
C. Beyan et al. / Transfusion and Apheresis Science 33 (2005) 47–50
donation for 33 donors and seven donors have undergone apheresis procedure repeated times. Blood groups of donors were A in 13, B in 9, O in 11 and AB in 7 subjects. Apheresis was performed by COBE Spectra on 21, Fenwall CS 3000 Plus on nine and Fresenius AS-204 on 10 donors. According to the directives of manufacturers, acid citrate dextrose formula-A (ACD-A) solution which is the anticoagulant using during procedure, was used in the amount of 0.8 ml/min of infusion rate for each liter of total amount of blood in COBE Spectra users and in Fresenius AS-204 and Fenwall CS 3000 users was applied as the ACD-A/blood ratio being 1/8 and 1/9, respectively. STA Compact (Diagnostica Stago) was used for measurements of prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and plasminogen levels. PT was measured with STA Neoplastine Cl Plus 5 (Cat. No. 00606), APTT with STA-CK Prest (Cat. No. 00597), TT with STA-Thrombin (Cat. No. 00669) and plasminogen with STA-Stachrom Plasminogen (Cat. No. 00658). Samples were collected from donors before and after platelet apheresis. For comparisons, paired t-test was used. All results were given as mean ± standard deviation (SD). An a level of 0.05 was considered to be statistically significant. Statistical analysis was done with MS Excel 2000 software.
3. Results Significant prolongation in PT, decrement in plasminogen levels and no significant change in APTT and TT were observed when compared
the values obtained before and after platelet apheresis (Table 1). The differences in these tests were not high enough to cause any clinically important hemostasis problem and no clinically significant bleeding episode or thrombosis was observed. It was thought that the changes in tests could be related to the anticoagulant solution ACD-A used during procedure. But, there was no correlation between the amount of ACD-A solution used and the magnitude of deviation in PT and APTT tests and the level of decrement in plasminogen.
4. Discussion Although apheresis is frequently performed nowadays, there is limited number of studies evaluating its effects in donors. Bosch et al. [1] investigated the efficacy and safety of citrate anticoagulation in direct adsorption of lipoproteins (DALI) apheresis in hypercholesterolemic patients. In this study, citrate was used as being the ratio of ACD-A/blood was 1/20 and 1/40, and the investigators found that both dilutions were safe. They did not observe any bleeding complication or thrombus in afferent line of extracorporeal circuit. They observed slight prolongation in PT with both anticoagulation regimens. In this study, changes in tests were similar although different doses of citrate were administered. We also did not find any correlation between the dose of citrate administered and the derangements in hemostasis tests in our study. Citrate has been the anticoagulant of choice in plateletpheresis procedures for more than two decades [2]. Theoretically, while 1 mol of citrate binds one calcium atom, 3 mol of citrate are needed for
Table 1 Test results and statistical comparisons Tests (n = 40)
PT (INR) APTT (s) TT (s) Plasminogen (%) a
NS = not significant.
Before apheresis
After apheresis
p-Value
Mean ± SD
Range
Mean ± SD
Range
1.14 ± 0.11 32.97 ± 3.90 17.06 ± 1.46 97 ± 15
0.95–1.43 25.4–43.1 13.2–21.1 73–144
1.28 ± 0.26 35.26 ± 7.17 17.29 ± 1.89 83 ± 14
1.01–2.38 26.7–59.5 12.9–25.1 54–119
0.0028 NSa NS 0.00009
C. Beyan et al. / Transfusion and Apheresis Science 33 (2005) 47–50
one calcium atom for the anticoagulant effect of citrate could be seen [2]. The relationship between citrate and calcium is not stable and it is possible to observe differences between individuals and it is still a problem to observe thrombus even at a dose of citrate thought to be appropriate. Citrate is metabolized very quickly in human beings and no citrate toxicity is observed except the patients with hepatic failure. But, Bolan et al. [3] showed that acute citrate overload could affect renal excretion during platelet apheresis. Variable affinity of citrate to calcium and the possibility of interactions in metabolism could explain why there is no relationship between the dose of citrate used and the amount of changes in hemostasis tests. Kobayashi et al. [4] studied the effects of Fenwall CS-3000 on coagulation and fibrinolytic system in platelet apheresis donors. They compared the values obtained before and after platelet apheresis and after apheresis they found a significant increase in prothrombin fragment-F 1 + 2 and thrombin–antithrombin complex, a slight increase in fibrinopeptide A and a slight decrease in alpha 2-plasmin inhibitor. Investigators concluded that Fenwall CS-3000 produces a hypercoagulable state and it is possible to prevent the hypercoagulable state in donors by changing disposable plastic material with a material refractory for thrombosis. Parallel to the results of this study, we found a decrease in plasminogen levels in our study. Plasminogen insufficiency is a risk factor for thrombosis according to some authors. For some authors, this insufficiency is not a thrombosis risk factor solely but rather a factor which augments the clinical risk of other hemostatic derangements [5]. If we evaluate the importance of decrement in plasminogen levels after platelet apheresis in healthy donors in accordance with these findings, it is not expected to observe any thrombotic event in healthy donors. But, the risk of low plasminogen level after platelet apheresis in triggering a thrombotic event in the presence of a genetic disorder such as factor V Leiden or prothrombin gene mutation should not be overlooked. The importance of history, physical examination and screening tests in donor recruitment are noted in the guideline [6] and especially the history of bleeding and thrombosis diathesis should be asked by the physician. More
49
detailed investigation is advised if there is any suspicion. The changes in PT and plasminogen levels observed after platelet apheresis might be speculated in a different mechanism. Citrate transiently binds ionized calcium and if sufficient ionized calcium is bound, there is minimal activation of platelets; however centrifugation and exposure to plastics also activates platelets and monocytes. This could lead to some activation of the coagulation and/or fibrinolytic system which could explain the slight drop in plasminogen in this study. Furthermore, the test method for the PT involves the addition of calcium and phospholipids to citrated plasma. Normal individuals and patients are assumed to have normal levels of ionized calcium when samples are drawn for PT testing; the amount of calcium added is constant, so the outcome is a PT value between normal levels. However, the starting sample was taken from a platelet donor at the end of the procedure, and if the ionized calcium level was diminished by the ACD-A used in the platelet collection procedure, then the amount of calcium added for the test may have been inadequate to provide a normal result. In this instance, the prolongation of the PT is due to a laboratory artifact and not to a physiological change in hemostasis in the patient. Tests of APTT and TT use different reagents in the test methods and are not sensitive to the changes in ionized calcium. Thus, these tests were normal in this study. As a result, it can be stated that platelet apheresis procedure affects PT and plasminogen levels, this interaction is related to the anticoagulant solution ACD-A, there is no relation between the amount of ACD-A used and the changes in tests and these changes produces no clinically significant risk in donors. But, in the presence of obscure clinical entities predisposing bleeding diathesis or thrombosis, it should be taken into consideration that apheresis procedure could be a risk factor for the donor.
References [1] Bosch T, Heinemann O, Duhr C, Wendler T, Keller C, Fink E, et al. Effect of low-dose citrate anticoagulation on the
50
C. Beyan et al. / Transfusion and Apheresis Science 33 (2005) 47–50
clinical safety and efficacy of direct adsorption of lipoproteins (DALI apheresis) in hypercholesterolemic patients: a prospective controlled clinical trial. Artif Organs 2000;24:790–6. [2] Mollison PL. The introduction of citrate as an anticoagulant for transfusion and of glucose as a red cell preservative. Br J Haematol 2000;108:13–8. [3] Bolan CD, Greer SE, Cecco SA, Oblitas JM, Rehak NN, Leitman SF. Comprehensive analysis of citrate effects during plateletpheresis in normal donors. Transfusion 2001;41:1165–71.
[4] Kobayashi I, Hamaoka S, Ozawa H, Ihno M, Tamura K, Tanaka Y, et al. Hypercoagulable state induced by thrombocytapheresis. J Clin Apheresis 1993;8:147–52. [5] Brandt JT. Plasminogen and tissue-type plasminogen activator deficiency as risk factors for thromboembolic disease. Arch Pathol Lab Med 2002;126:1376–81. [6] Joint Working Party of the Transfusion and Clinical Haematology Task Forces of the British Committee for Standards in Haematology. Guidelines for the clinical use of blood cell separators. Clin Lab Haematol 1998;20:265– 78.
Platelet apheresis affects prothrombin time and plasminogen levels in healthy donors Cengiz Beyan *, Ku¨rs‚at Kaptan, Serap Savas‚c¸ı, Ahmet Ifran, ¨ ztu¨rk, Birgu¨l O ¨ kmen Yes‚im O Department of Hematology, Gulhane Military Medical Academy, Etlik, 06010 Ankara, Turkey Received 21 September 2004; received in revised form 7 February 2005; accepted 13 February 2005
Abstract There are few studies evaluating whether platelet apheresis has an effect on hemostasis parameters or not. The aim of this study was to define the effects of platelet apheresis on hemostasis screening tests and plasminogen levels. The study was performed on 40 healthy donors. We compared the values obtained before and after apheresis and observed that the prothombin time (PT) elongated, plasminogen levels decreased and the activated partial thromboplastin and thrombin times were not changed significantly. The differences were not high enough to cause any hemostasis problem. It can be hypothesized that platelet apheresis affects PT and plasminogen levels in healthy donors. Ó 2005 Elsevier Ltd. All rights reserved.
1. Introduction Although platelet apheresis is frequently performed nowadays, there are few studies evaluating whether or not it has an effect on hemostasis parameters or not. Although many donors undergo repeated plateletpheresis, data on the consequences of plateletpheresis for the donorÕs health is scarce. * Corresponding author. Tel.: +90 312 304 41 01; fax: +90 312 304 41 00. E-mail addresses: [email protected], cbeyan@ yahoo.com (C. Beyan).
The aim of this study was to define the effects of platelet apheresis on hemostasis screening tests and plasminogen levels.
2. Materials and methods The study was carried on 40 healthy apheresis donors consisting of 36 men and four women whose mean age was 24.63 ± 6.22 years (range 20–46). Donors met the American Association of Blood Banks eligibility criteria for plateletpheresis donation and gave informed consent for participation in the study. Platelet apheresis was the first
1473-0502/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.transci.2005.02.003
48
C. Beyan et al. / Transfusion and Apheresis Science 33 (2005) 47–50
donation for 33 donors and seven donors have undergone apheresis procedure repeated times. Blood groups of donors were A in 13, B in 9, O in 11 and AB in 7 subjects. Apheresis was performed by COBE Spectra on 21, Fenwall CS 3000 Plus on nine and Fresenius AS-204 on 10 donors. According to the directives of manufacturers, acid citrate dextrose formula-A (ACD-A) solution which is the anticoagulant using during procedure, was used in the amount of 0.8 ml/min of infusion rate for each liter of total amount of blood in COBE Spectra users and in Fresenius AS-204 and Fenwall CS 3000 users was applied as the ACD-A/blood ratio being 1/8 and 1/9, respectively. STA Compact (Diagnostica Stago) was used for measurements of prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and plasminogen levels. PT was measured with STA Neoplastine Cl Plus 5 (Cat. No. 00606), APTT with STA-CK Prest (Cat. No. 00597), TT with STA-Thrombin (Cat. No. 00669) and plasminogen with STA-Stachrom Plasminogen (Cat. No. 00658). Samples were collected from donors before and after platelet apheresis. For comparisons, paired t-test was used. All results were given as mean ± standard deviation (SD). An a level of 0.05 was considered to be statistically significant. Statistical analysis was done with MS Excel 2000 software.
3. Results Significant prolongation in PT, decrement in plasminogen levels and no significant change in APTT and TT were observed when compared
the values obtained before and after platelet apheresis (Table 1). The differences in these tests were not high enough to cause any clinically important hemostasis problem and no clinically significant bleeding episode or thrombosis was observed. It was thought that the changes in tests could be related to the anticoagulant solution ACD-A used during procedure. But, there was no correlation between the amount of ACD-A solution used and the magnitude of deviation in PT and APTT tests and the level of decrement in plasminogen.
4. Discussion Although apheresis is frequently performed nowadays, there is limited number of studies evaluating its effects in donors. Bosch et al. [1] investigated the efficacy and safety of citrate anticoagulation in direct adsorption of lipoproteins (DALI) apheresis in hypercholesterolemic patients. In this study, citrate was used as being the ratio of ACD-A/blood was 1/20 and 1/40, and the investigators found that both dilutions were safe. They did not observe any bleeding complication or thrombus in afferent line of extracorporeal circuit. They observed slight prolongation in PT with both anticoagulation regimens. In this study, changes in tests were similar although different doses of citrate were administered. We also did not find any correlation between the dose of citrate administered and the derangements in hemostasis tests in our study. Citrate has been the anticoagulant of choice in plateletpheresis procedures for more than two decades [2]. Theoretically, while 1 mol of citrate binds one calcium atom, 3 mol of citrate are needed for
Table 1 Test results and statistical comparisons Tests (n = 40)
PT (INR) APTT (s) TT (s) Plasminogen (%) a
NS = not significant.
Before apheresis
After apheresis
p-Value
Mean ± SD
Range
Mean ± SD
Range
1.14 ± 0.11 32.97 ± 3.90 17.06 ± 1.46 97 ± 15
0.95–1.43 25.4–43.1 13.2–21.1 73–144
1.28 ± 0.26 35.26 ± 7.17 17.29 ± 1.89 83 ± 14
1.01–2.38 26.7–59.5 12.9–25.1 54–119
0.0028 NSa NS 0.00009
C. Beyan et al. / Transfusion and Apheresis Science 33 (2005) 47–50
one calcium atom for the anticoagulant effect of citrate could be seen [2]. The relationship between citrate and calcium is not stable and it is possible to observe differences between individuals and it is still a problem to observe thrombus even at a dose of citrate thought to be appropriate. Citrate is metabolized very quickly in human beings and no citrate toxicity is observed except the patients with hepatic failure. But, Bolan et al. [3] showed that acute citrate overload could affect renal excretion during platelet apheresis. Variable affinity of citrate to calcium and the possibility of interactions in metabolism could explain why there is no relationship between the dose of citrate used and the amount of changes in hemostasis tests. Kobayashi et al. [4] studied the effects of Fenwall CS-3000 on coagulation and fibrinolytic system in platelet apheresis donors. They compared the values obtained before and after platelet apheresis and after apheresis they found a significant increase in prothrombin fragment-F 1 + 2 and thrombin–antithrombin complex, a slight increase in fibrinopeptide A and a slight decrease in alpha 2-plasmin inhibitor. Investigators concluded that Fenwall CS-3000 produces a hypercoagulable state and it is possible to prevent the hypercoagulable state in donors by changing disposable plastic material with a material refractory for thrombosis. Parallel to the results of this study, we found a decrease in plasminogen levels in our study. Plasminogen insufficiency is a risk factor for thrombosis according to some authors. For some authors, this insufficiency is not a thrombosis risk factor solely but rather a factor which augments the clinical risk of other hemostatic derangements [5]. If we evaluate the importance of decrement in plasminogen levels after platelet apheresis in healthy donors in accordance with these findings, it is not expected to observe any thrombotic event in healthy donors. But, the risk of low plasminogen level after platelet apheresis in triggering a thrombotic event in the presence of a genetic disorder such as factor V Leiden or prothrombin gene mutation should not be overlooked. The importance of history, physical examination and screening tests in donor recruitment are noted in the guideline [6] and especially the history of bleeding and thrombosis diathesis should be asked by the physician. More
49
detailed investigation is advised if there is any suspicion. The changes in PT and plasminogen levels observed after platelet apheresis might be speculated in a different mechanism. Citrate transiently binds ionized calcium and if sufficient ionized calcium is bound, there is minimal activation of platelets; however centrifugation and exposure to plastics also activates platelets and monocytes. This could lead to some activation of the coagulation and/or fibrinolytic system which could explain the slight drop in plasminogen in this study. Furthermore, the test method for the PT involves the addition of calcium and phospholipids to citrated plasma. Normal individuals and patients are assumed to have normal levels of ionized calcium when samples are drawn for PT testing; the amount of calcium added is constant, so the outcome is a PT value between normal levels. However, the starting sample was taken from a platelet donor at the end of the procedure, and if the ionized calcium level was diminished by the ACD-A used in the platelet collection procedure, then the amount of calcium added for the test may have been inadequate to provide a normal result. In this instance, the prolongation of the PT is due to a laboratory artifact and not to a physiological change in hemostasis in the patient. Tests of APTT and TT use different reagents in the test methods and are not sensitive to the changes in ionized calcium. Thus, these tests were normal in this study. As a result, it can be stated that platelet apheresis procedure affects PT and plasminogen levels, this interaction is related to the anticoagulant solution ACD-A, there is no relation between the amount of ACD-A used and the changes in tests and these changes produces no clinically significant risk in donors. But, in the presence of obscure clinical entities predisposing bleeding diathesis or thrombosis, it should be taken into consideration that apheresis procedure could be a risk factor for the donor.
References [1] Bosch T, Heinemann O, Duhr C, Wendler T, Keller C, Fink E, et al. Effect of low-dose citrate anticoagulation on the
50
C. Beyan et al. / Transfusion and Apheresis Science 33 (2005) 47–50
clinical safety and efficacy of direct adsorption of lipoproteins (DALI apheresis) in hypercholesterolemic patients: a prospective controlled clinical trial. Artif Organs 2000;24:790–6. [2] Mollison PL. The introduction of citrate as an anticoagulant for transfusion and of glucose as a red cell preservative. Br J Haematol 2000;108:13–8. [3] Bolan CD, Greer SE, Cecco SA, Oblitas JM, Rehak NN, Leitman SF. Comprehensive analysis of citrate effects during plateletpheresis in normal donors. Transfusion 2001;41:1165–71.
[4] Kobayashi I, Hamaoka S, Ozawa H, Ihno M, Tamura K, Tanaka Y, et al. Hypercoagulable state induced by thrombocytapheresis. J Clin Apheresis 1993;8:147–52. [5] Brandt JT. Plasminogen and tissue-type plasminogen activator deficiency as risk factors for thromboembolic disease. Arch Pathol Lab Med 2002;126:1376–81. [6] Joint Working Party of the Transfusion and Clinical Haematology Task Forces of the British Committee for Standards in Haematology. Guidelines for the clinical use of blood cell separators. Clin Lab Haematol 1998;20:265– 78.