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THROMBOSIS AND THALASSEMIA
Prof.Dr.Tansu SipahiUfuk University, Faculty of Medicine, Department of
Pediatric Hematology
3rd InternationalCongress of Molecular Medicine, Istanbul, Turkey, May 5-8, 2009
Thalassemia is a congenital hemolytic disease caused by defective globin synthesis resulting in decreased quantity of globin chains.
Worldwide, about 300 000 infants are born each year with a hb.pathy and an estimated 5% of the world’s population are carriers of a gene mutation for autosomal recessive conditions.
The severity of clinical course distinguishes this disease into two main subtypes: – Thalassemia major (TM) – Thalassemia intermedia (TI)
The severity of clinical course distinguishes this disease into two main subtypes: – Thalassemia major (TM) – Thalassemia intermedia (TI)
Currently used therapeutic approaches such as regular blood transfusions and iron chelation have prolonged life expectancy in patients with thalassemia.
A consequence of this brings new complications
Deep venous thrombosis (DVT)
Portal venous thrombosis (PVT)
Pulmonary embolism (PE)
Cerebral thromboembolism (CTE)
Postsplenectomy thrombosis
In recent years, thromboembolic events have been increasingly recognized.
However, there are relatively few epidemiological data on the overall frequency of these complications.
Prevalence of thromboembolic episodes in -thalassemia in previous studies
Abbreviations: PTE, pulmonary thromboembolism; PVT, portal vein thrombosis; DIC, disseminated intravascular coagulation; CNS, central nervous system; STP, superficial thrombophlebitis.
Taher et al. Blood Reviews 2008; 22: 283-292
Reference (year) # of patients with thromboembolism (%)
Sites of thromboembolism
Michaeli et al. (1992) 4 (TM)4%
Recurrent arterial occlusion, recurrent PTE, venous thrombosis and one fatal stroke
Aessopos et al. (1997) 6 (3 TM, 3 TI)1%
Thrombotic strokes
Moratelli et al. (1998) 26 (14 TM, 12 TI)5.3% (overall), 3.3% (TM), 16.2% (TI)
-
Borgna Pignatti et al. (1998)
32 (27 TM, 5 TI)3.27% (TM + TI)
Thrombotic strokes-16, MT-1, PVT-2, DVT-6, intraatrial thrombosis-2, DIC in pregnancy-2, PTE-3
Akar et al. (1998) 17 homozygous -thalassemia Nine had CNS involvementSenanayake and Lamabadusuriya (2001)
2 homozygous -thalassemia Cerebral thrombosis (hemiparesis)
Cappellini et al. (2000) 24 TI29%
PVT-9, DVT-3, STP-10, PTE-3, Priapism-1
Zalloua et al. (2003) 4 TI8%
Not specified
Taher et al. (2006) 85 TI (3.9%), 61 TM (0.9%)Overall (1.65%)
DVT 32%, stroke 18%, PVT 16%, PE 13% and STP 4.7%
Zurlo et al. (1989)
A study concerning survival and causes of death in TM patients showed thromboembolism represented the primary cause of death in about 2.5% (4 of 159)of the transfusion dependent thalassemic patients.
Zurlo MG. Lancet 1989; 2: 27-30
Pignatti et al. (1998)In a survey involving 9 Italian thalassemia centers, (735 patients),overall prevalence of TE episodes– Thalassemia major (n=683) 2.3 %– Thalassemia intermedia (n=52) 9.6 %
Pignatti CB. Haematologica 2004; 89: 1187
Pignatti CB. Acta Haematol 1998; 99: 76-79
Pignatti et al. (2004)Seven Italian centers1073 patientsPrimary cause of death 4.1% (thrombosis)
Causes of death for the entire population of patients
All patients (N=1073)N %
Heart Failure 133 60.2Infection 15 6.8Arrhytmia 15 6.8Myocardial infarction 4 1.8Cirrhosis 9 4.1Thrombosis 9 4.1Malignancy 8 3.6Diabetes 7 3.2Accident 4 1.8Renal Failure 3 1.4HIV/AIDS 3 1.4Familial autoimmune disorder 2 0.9Anorexia 1 0.5Hemolytic anemia 1 0.5Thrombocytopenia 1 0.5Unknow 6 2.7Total 221
Borgna-Pignatti et al. Haematologica 2004
Akar et al. (1998)
The Turkish Thalassemia Study Group
compile data from 11 Centers. Of the
519 homozygous -thalassemia
patients(442 TM, 77 TI). Seventeen
(3.27%) had experienced thrombosis.
Akar N. Acta Haematol 1998
Cappellini et al. (2000)83 patients -TI29% of patients developed thromboembolic events (PE, DVT, PVT)(10 years follow-up)9 of these patients recurrent VTEsAll patients except one had undergone splenectomy
Cappellini et al. Br J Haematol 2000
Taher et al. (2006)
8860 thalassemia patients
1.65% of patients had TE events
Thromboembolic events occured 4.38 times more frequently in TI than TM, with more venous events occuring in TI and more arterial events occuring in TM
OR:4.38 (%95 CI:3.14-6.10)
Taher et al. Thromb Haemost 2006
Patient characteristics*
*Not all patients responded to every question, so presented frequencies are based on responder numbers only. TI, thalassaemia intermedia; TM, thalassaemia major.
TI (n=85) TM (n=61) All patients (n=146)Males % 42.4 (36/85) 51.7 (31/60) 46.2 (67/145)Females % 57.6 (49/85) 48.3 (29/60) 53.8 (78/145)Mean age at time of event, years
33.4 ± 14.9 25.1 ± 8.8 30.0 ± 13
Splenectomized % 94.0 (78/83) 91.8 (56/61) 93.0 (134/144)Haemoglobin <9 g/dl, % 67.5 (52/77) 43.3 (26/60) 56.9 (78/137)Regularly transfused % 33.3 (28/84) 93.3 (56/60) 58.3 (84/144)Recurrent thrombosis % 35.6 (26/73) 25.0 (13/52) 31.2 (39/125)Pulm. hypertension % 27.3 (15/55) 19.5 (8/41) 24.0 (23/96)Aspirin % 51.0 (26/51) 52.5 (21/40) 51.6 (47/91)Hydroxyurea % 35.3 (18/51) 4.7 (2/43) 21.3 (20/94)
Taher et al. Thromb Haemost 2006
Thromboembolic events in TI and TM (%)
12
8
19
12
39
9
66
30
0
11
8
23
28
48
0 20 40 60 80
Others
STP
PVT
PE
DVT
Stroke
Venous
Type
of e
vent
Thromboembolic events (%)
TI (n=85) TM (n=61)
Taher A et al. Thromb Haemost 2006; 96: 488-91
Cerebral TE events, stroke syndrome, and neurological findings were also found in patients with beta thalassemia.The incidence of stroke 2% to 20%.
Manfre L. AJR 1999
Pignatti . Acta Hemotologica 1998
Asymptomatic brain damage on MRI has also been reported on patients with TI as a frequent occurence affecting 37% of patients.
Autopsy series in patients with TM and TI describe the presence of Pulmonary embolism, arterial occlusion, thrombi in small and large pulmonary vessels.
Chronic hypoxia and lung injuries due to infectionsExcessive iron depositionRight ventricular dysfunctionIncreased platelet activationMicroembolization in the lungs
Singer ST et al. Am J Hematol 2006
As a result of multiple recent clinical studies and laboratory data, thalassemia has been referred to as a “hypercoagulable state”.
Several factors are implicated in the etiopathogenesis of the hypercoagulable state; namely inherent abnormality in the red cells, cardiac dysfunction, liver dysfunction, hypothyroidism, diabetes and post splenectomy thrombocytosis.
Summary of the pathogenesis of hypercoagulability in thalassemia
Pathogenesis Description of the problem ReferencePlatelet activation Increased platelet aggregation,
increased expression of activation markers, presence of platelet morphologic abnormalities
Winichagoon et al., Del Principe et al., Ruf et al., Bunyaratvej et al., Eldor et al.
Pathology and alteration in red blood cells
Formation and precipitation of hemichromes, formation of reactive oxygen species, expression of negatively charged phospholipids which facilitate thrombin generation, enhanced cohensiveness and aggreability
Kuypers and de Jong, Borenstain-Ben Yashar et al., Helley et al., Chen et al.
Endothelial cell and peripheral blood activation
Expression of endothelial adhesion molecules and tissue factor on endothelial cells, formation of microparticles, monocyte and granulocyte activation
Carlos and Harlan, Pattanapanyasat et al. (2004), Pattanapanyasat et al. (2007), Wiener et al., Deo et al.
Splenectomy High platelet counts following splenectomy, platelet hyperactivity
Eldor and Rachmilewitz, Atichartakarn et al.
Thrombophilic DNA mutations and acquired changes in coagulation factors and inhibitors
High prevalence for both the factor V Leiden, decreased levels of antithrombin III, protein C and protein S. Anti-phospholipid antibodies
Zalloua et al., Eldor et al., Cappellini et al., Iolascon et al., Giordano et al., Sharma et al., Kashef et al.
PATHOGENESIS
Factors contributing to the hypercoagulable state in thalassemia
Hypercoagulable State
Iron overloadHyperviscosityEndothelial damageMonocyte activationRelease of microparticles
Genetic mutationsFactor V LeidenProthrombin G20210MTHFR C677T(hyperhomocysteinemia)? Others
Cardiac dysfunctionLiver dysfunctionHormonal deficienciesAntiphospholipid antibodies? Intravascular hemolysis
Decreased levels ofProtein CProtein SAntithrombin III
PlateletsIncreased platelet aggregationState of oxidative stress (ROS)Expression of activation markers (CD62P and CD63)
Taher et al. Blood Reviews 2008; 22: 283-292
Red Blood CellsAbnormal erythroid cellsSource of procoagulant phospholipidsEnhanced cohesiveness
PATHOGENESIS
Factors contributing to the hypercoagulable state in thalassemia
Hypercoagulable State
Red Blood CellsAbnormal erythroid cellsSource of procoagulant phospholipidsEnhanced cohesiveness
Iron overloadHyperviscosityEndothelial damageMonocyte activationRelease of microparticles
Genetic mutationsFactor V LeidenProthrombin G20210MTHFR C677T(hyperhomocysteinemia)? Others
Cardiac dysfunctionLiver dysfunctionHormonal deficienciesAntiphospholipid antibodies? Intravascular hemolysis
Decreased levels ofProtein CProtein SAntithrombin III
PlateletsIncreased platelet aggregationState of oxidative stress (ROS)Expression of activation markers (CD62P and CD63)
Taher et al. Blood Reviews 2008; 22: 283-292
Under normal conditions, the choline-containing phospholipids, phosphatidylcholine(PC) and sphingomyelin(SM) are mainly present in the outer monolayer of the plasma membrane, where as phosphatidylserine (PS) is exclusively and phosphatidylethanolamine (PE) is mainly found in the inner monolayer.
Kuypers, ASH, Hematology, 2007
Red Blood Cells
In normal RBC, maintenance of membrane phospholipid asymmetry appears to be provided by the action of an ATP-dependent aminophospholipid translocase ( flipase), that transportsPS and PE from the outer to the inner membrane surface.
Red Blood Cells
Phospholipid Organisation of Red Blood Cells
Kuypers, ASH, Hematology, 2007
Red Blood Cells
The Hypercoagulable State in Thalassemia
Eldor A. Blood 2002; Kuypers&de Jong 2004; Rund&Rachmilewitz 2005
Endothelial activation Thrombus formation Endothelial perturbation
Low plasma protein C and protein S
RBC adhesion and aggregation
Fibrin
Platelets
Fibrinogen
Activation of granulocytes
and monocytes
RBC
Tissue factor
Prothrombinasecomplex
Red Blood Cells
Ataga et al.2007
Pathophysiology of hypercoagulable state in thalassemia
Rund et al.2005
Atichartakran et al. Annexin V labelling of RBCs using flow cytometry
These findings indicated that splenectomized patients with Hb E/β-thalassemia were in a chronic
hypercoagulable state. increased numbers of circulating PS-exposed RBCs
Atichartakran et al. 2002
Red Blood Cells
Several studies have demonstrated that RBCs from thalassemia patients also show enhanced cohesiveness and aggregability. RBCs may also act as activated platelets and enhance conversion of prothrombin thrombinEnhanced adherence of the abnormal erythrocytes to endothelial cells is also described.
Hovav T. Br J Haematol 1999
Red Blood Cells
PATHOGENESIS
Factors contributing to the hypercoagulable state in thalassemia
Hypercoagulable State
Red Blood CellsAbnormal erythroid cellsSource of procoagulant phospholipidsEnhanced cohesiveness
Iron overloadHyperviscosityEndothelial damageMonocyte activationRelease of microparticles
Genetic mutationsFactor V LeidenProthrombin G20210MTHFR C677T(hyperhomocysteinemia)? Others
Cardiac dysfunctionLiver dysfunctionHormonal deficienciesAntiphospholipid antibodies? Intravascular hemolysis
Decreased levels ofProtein CProtein SAntithrombin III
PlateletsIncreased platelet aggregationState of oxidative stress (ROS)Expression of activation markers (CD62P and CD63)
Taher et al. Blood Reviews 2008; 22: 283-292
Platelet abnormalitiesIncreased platelet aggregationChronic platelet activationIncreased circulating platelet aggregatesShortened platelet survivalEnhanced excretion of urinary metabolites of thromboxane A2 (TxA2) and prostacyclinExpression the activation markers (CD62P and CD63)(flow cytometry)
Platelets
Eldor et al.
A significant increase (4-10 fold) in the urinary excretion of the stable hydrolysis products of TxA2, and PGI2 in beta-thalassemia patients compared to controls. The platelet life span is shortened– 107 ± 36 hour in splenectomized patients– 248 ± 51 hour in splenectomized controls
Eldor A et al. Am J Hematol 1989
Platelets
Goldschmidt et al.
Platelet adhesion under flow condition, the primary event in thrombus formation, is increased in thalassemic patients as compared to healthy controls.
Thalassemic red blood cells promote platelet adhesion under flow.
Goldschmidt et al. Thromb Haemost 2008
Platelets
PATHOGENESIS
Factors contributing to the hypercoagulable state in thalassemia
Hypercoagulable State
Red Blood CellsAbnormal erythroid cellsSource of procoagulant phospholipidsEnhanced cohesiveness
Iron overloadNO deficiencyEndothelial damageMonocyte activationRelease of microparticles
Genetic mutationsFactor V LeidenProthrombin G20210MTHFR C677T(hyperhomocysteinemia)? Others
Cardiac dysfunctionLiver dysfunctionHormonal deficienciesAntiphospholipid antibodies? Intravascular hemolysis
Decreased levels ofProtein CProtein SAntithrombin III
PlateletsIncreased platelet aggregationState of oxidative stress (ROS)Expression of activation markers (CD62P and CD63)
Taher et al. Blood Reviews 2008; 22: 283-292
Endothelial cells, monocytes and granulocyte activation
Elevated levels of endothelial adhesion proteins – Vascular cell adhesion molecule-1 (VCAM-1)– Intercellular adhesion molecule-1 (ICAM-1)– E-selectin (ELAM-1)– Von Willebrand factor (vWF)– ThrombomodulinEndothelial injury and activation
Butthep P. Thromb Hemost 1995, Hovav T. 1999
Monocyte, Endothelial Cells
Adherence of red blood cells (RBC) from -thalassaemia major (TM) and intermedia (TI)
patients to endothelial cells (EC)
RBC of the indicated composition were placed on confluent cultured bovine aortic endothelial cells for 45 min then washed five times with PBS, and the number of RBC remaining adhered to the EC were counted as described in Methods. Each datum is mean ±SD for six experiments (with blood samples taken from six patients). To examine the effect of the dilution of pathological RBC with normal RBC ones. TI-RBC were mixed with 30% of normal RBC because the dilution of TM-RBC by the routine transfusion of normal blood is usually about 30%.
RBC compositionAdherence (no. of RBC/103 EC)
Normal 32 ± 7TM prior to transfusion 342 ± 43TM after transfusion 321 ± 37TI 820 ± 54TI (70%) with normal (30%) 813 ± 66
Hovav T. Br J Haematol 1999; 106: 178-181
Monocyte, Endothelial Cells
Microparticles are small vesicles formed by the membrane, which is derived from RBCs, platelets, EC and monocytes following activation.
The number of RBC vesicles are especially marked following splenectomy in patients with beta-thalassemia/hemoglobin E.
Hugel B et al. Physiology 2005
Recently, in a study it was shown that these particles are also derived from activated platelets.
Pattanapanyasat K et al. Cytometry B Clin Cytom 2004
Pattanapanyasat K et al. Br J Haematol 2007
Monocyte, Endothelial Cells
Monocyte activation may play an important role in endothelial activation – High serum levels of monocyte colony-
stimulating factor
Granulocytes activation– Elevated granulocyte phagocytic function – Endothelial damage - Removal of leukocytes from transfused blood
resulted in improved pulmonary function tests.
Deo SS et al. Indian J Pediatr 1994 Kivity S et al. Pediatr Pulmonol 1999
Monocyte, Endothelial Cells
Intravascular hemolysis reduces nitric oxide bioactivity
Kato GJ et al. Blood Reviews 2007
NO deficiency
Intravascular hemolysis releases Hb, Arginase, LDH
Hb inactivates NO, generating MetHb and inert nitrat.
Plasma Arginase deplete NO production.
Decrease of NO is associated with Pulmonary.
Decrease of NO is associated with Pulmonary hypertension, priapism, leg ulceration and nonhemorrhagic stroke
The increased number of circulating abnormal RBC
Activation of platelets
Activation of the coagulation system
may contribute to the development
of TE phenomena in patients with βt
NO deficiency
HEMOLYSIS
NITRIC OXIDEEndothelial Cell DysfunctionProinflammatory EffectsProliferation
DECREASED NITRIC OXIDE SIGNALLING VIA cGMP
Impaired Regulation of Smooth Muscle Tone
Platelet Activation
Local Vasoconstriction
Intravascular Thrombosis
Smooth Muscle DystoniasVascular Constriction GI ContractionsPulmonary and Systemic Hypertension DysphagiaErectile Dysfunction Abdominal Pain
Cappellini MD et al. Am Soc Hematol 2007; adapted from Rother et al.
NO deficiency Consequences of nitric oxide depletion during intravascular hemolysis
Role of splenectomySummary of studies on the prevalence of thrombosis in splenectomized patientsAuthors No. of patients
splenectomizedPrevalence of thrombosis
Type of thrombosis Underling disease
Chaffanjon et al. 60 6.7% PVT (1 symtomatic, 3 asymptomatic)
Myeloproliferative disorder
Loring et al. 123 9.8% PVT (3 symtomatic, 9 asymptomatic)
Hematologic diseases (myelofibrosis, MDS, lymphoma, leukemia)
Valeri et al. 12 8.3% PVT ITPVan’t Riet et al. 563 1.6% PVT 10% autoimmune
hemolytic anemia and myeloproliferative
syndromeTefferi et al. 223 7% TE Myelofibrosis with
myeloid metaplasiaHassn et al. 50 10% PVT ?Cappellini et al. 83 29% TE Thalassemia intermediaDelaitre et al. 275 10% TE Hematologic diseasesAkpek et al. 26 12% VT Myelofibrosis with
myeloid metaplasiaWinslow et al. 101 8% PVT 74% hematologic disease
(myeloproliferative disorder)
Fujita et al. 321 1.5% PVT Hemolytic anemia thalassemia and
myelofibrosisIkeda et al. 22 (LS)
21 (OS)55% (LS)
33% symp-tomatic 19% (OS)
Portal vein, mesenteric veins,
splenic vein
?
Cappellini MD. Ann NY Acad Sci 2005
Splenectomy
The development of these complications has been attributed to the presence of high platelet counts following splenectomy and/or to increased number of abnormal RBC.
Eldor A. Blood 2002
A multicenter study (56 tertiary referral centers,8860 patients),146 (1.65%)TE events.The highest prevalence of thrombotic events was observed in splenectomized patients.
Taher A. Thromb Haemost 2006
Splenectomy
Taher et al.
Eldor A.
The most significant changes occurred in the severe splenectomized group who have a higher risk for thrombosis than comparable patients with intact spleen.
Tripatara A et al. Thrombosis Res 2007
Test Normal (mean±SD)
Severe non-splenectomized
(mean±SD)
Severe splenectomized
(mean±SD)TAFI (%) 115±17 108±22 95±12a,b
Factor V (%) 114±15 108±18 94±12a,b
Factor VII (%) 98±13 94±14 88±9Factor VIII (%) 98±14 91±43 71±17a,b
Factor IX (%) 97±36 98±39 77±29Factor XI (%) 86±19 81±37 78±37Prothrombin (%) 86±12 87±14 86±13Fibrinogen (mg/dl) 261±40 220±42a 218±38a
Protein C (%) 94±21 58±10a 63±14a
Protein S (%) 92±35 68±19a 53±25a
Tripatara et al.
The alterations in the activity of coagulation and fibrinolytic proteins in normal individuals and in severe non-splenectomized and severe splenectomized -thalassemia/Hb E patients
For comparison purposes, values for NS group were prothrombin=87±13%; fibrinogen=189±47%; protein C=76±21%; protein S=59±20%.ap<0.05, in comparison with normal control.bp<0.05, in comparison with severe non-splenectomized.
Splenectomy
Thrombocytosis
The increased number of circulating abnormal RBC
Activation of platelets
Activation of the coagulation system
may contribute to the development
of TE phenomena in patients with βt
Splenectomy
Alterations in markers of coagulation activation
The marker of thrombin generation– Prothrombin fragment 1.2 (F 1.2)– Fibrinopeptide A
The marker of increased fibrinolysis– Thrombin – antithrombin complexes– D-dimer
Thrombin generation by red cells and erythroid cells of patients with thalassemia intermedia and major
**P < 0.001 compared with patients with thalassaemia intermedia who were non-splenectomized and compared with patients with thalassaemia major and healthy individuals.
No. of individuals Generated thrombin (nmol/min/ml)
Thalassaemia intermediaNon-splenectomized 5 22.6±3.4Splenectomized 9 42.9±16.8*
Thalassaemia majorNon-splenectomized 3 29.7±1.3Splenectomized 3 23.0±11.1
Healthy individualsNon-splenectomized 11 28.6±3.6Splenectomized 8 26.3±4.4
Cappellini MD et al. Br J Haematol 2000; 111: 467-473
PATHOGENESIS
Factors contributing to the hypercoagulable state in thalassemia
Hypercoagulable State
Red Blood CellsAbnormal erythroid cellsSource of procoagulant phospholipidsEnhanced cohesiveness
Iron overloadHyperviscosityEndothelial damageMonocyte activationRelease of microparticles
Genetic mutationsFactor V LeidenProthrombin G20210MTHFR C677T(hyperhomocysteinemia)? Others
Cardiac dysfunctionLiver dysfunctionHormonal deficienciesAntiphospholipid antibodies? Intravascular hemolysis
Decreased levels ofProtein CProtein SAntithrombin III
PlateletsIncreased platelet aggregationState of oxidative stress (ROS)Expression of activation markers (CD62P and CD63)
Taher et al. Blood Reviews 2008; 22: 283-292
Decreased levels of anticoagulant proteins:
Protein C and Protein S levels Cappellini et al. Br J Haematol 2000
Protein C was low in 26.2% of patientsProtein S was low in 28.6% of patientsAT III was low in 46.8% of patients
Naithani R et al. Hematology 2006
Anticoagulant Proteins
Nature anticoagulant proteinsParameter No No. of patient with
abnormal valuesPercentag
eThrombocytopenia 54 18 33.3Prolonged PT 54 22 40.7Prolonged aPTT 54 25 46.3Protein C (70%) 42 11 26.2Protein S (70%) 42 12 28.6AT III (80%) 47 22 46.8Pr C + Pr S 42 1 2.4Pr C + AT III 42 6 14.3Pr S + AT III 42 5 11.9Pr C + Pr S + AT III 42 3 7.1
Naithani R et al. Hematology 2006
Anticoagulant Proteins Naithani et al.
Anticoagulant proteins and markers of coagulation and fibrinolysis activation in patients with
thalassemia intermedia and major
Values are expressed as mean ± 1SD.*P < 0.05 compared with healthy individuals.**P < 0.001 compared with healthy individuals.
No. of individuals
Protein C (IU/ml)
Antithrombin (IU/ml)
Fibrinopeptide (nmol/l)
Prothrombin fragment 1+2
(nmol/l)
D-dimer (ng/ml)
Thalassaemia intermedia
Non-splenectomized 10 0.54±0.10** 0.81±0.11** 0.8±0.3 0.7±0.3 36±26
Splenectomized 20 0.52±0.14** 0.80±0.10** 1.3±0** 1.2±0.7* 121±74**
Thalassaemia major
Non-splenectomized 8 - 0.96±0.13 0.7±0.1 1.1±0.3 17±9.3
Splenectomized 24 - 0.92±0.10** 1.1±0.7 1.0±0.2 34.5±24
Healthy individuals 30 0.87±0.11 0.98±0.07 0.8±0.3 0.9±0.3 27±16
Cappellini MD et al. Br J Haematol 2000; 111: 467-473
Anticoagulant Proteins
The most significant changes occurred in the severe splenectomized group who have a higher risk for thrombosis than comparable patients with intact spleen.
Tripatara A et al. Thrombosis Res 2007
Test Normal (mean±SD)
Severe non-splenectomized
(mean±SD)
Severe splenectomized
(mean±SD)TAFI (%) 115±17 108±22 95±12a,b
Factor V (%) 114±15 108±18 94±12a,b
Factor VII (%) 98±13 94±14 88±9Factor VIII (%) 98±14 91±43 71±17a,b
Factor IX (%) 97±36 98±39 77±29Factor XI (%) 86±19 81±37 78±37Prothrombin (%) 86±12 87±14 86±13Fibrinogen (mg/dl) 261±40 220±42a 218±38a
Protein C (%) 94±21 58±10a 63±14a
Protein S (%) 92±35 68±19a 53±25a
Tripatara et al.
The alterations in the activity of coagulation and fibrinolytic proteins in normal individuals and in severe non-splenectomized and severe splenectomized -thalassemia/Hb E patients
For comparison purposes, values for NS group were prothrombin=87±13%; fibrinogen=189±47%; protein C=76±21%; protein S=59±20%.ap<0.05, in comparison with normal control.bp<0.05, in comparison with severe non-splenectomized.
Anticoagulant Proteins
Thalassemia Major Patients with Abnormal Values of Hematological Parameters
Parameter No Number of patients with abnormal values (n)
Percentage (%)
Protein C deficiency 34 10 29.4%Protein S deficiency 34 13 38.2%AT III deficiency 34 1 2.9%Protein C and protein S deficiency
34 6 17.6%
Protein C and AT III deficiency
34 1 2.9%
Protein S and AT III deficiency
34 1 2.9%
Protein C, protein S and AT III deficiency
34 1 2.9%
Elevated FVIII level 24 2 8.3%Elevated FIX level 22 0 0
Sipahi T et al. Clin Appl Thromb Hemost 2008
Anticoagulant Proteins Sipahi et al.
Protein C and Protein S levels AT III = N
Protein C, protein S, TAFI, fibrinogen, Factor V and VIII in the splenectomized groups were statistically lower than those in control group.
Eldor A et al. 1999
Tripatara A et al. Thrombosis Res 2007
Anticoagulant Proteins
The presence of anti-phospholipid antibodies (aPL) reported a high prevalence (34%)
Kashef et al. reported ACA in 42.7%
Antiphospholipid ab
Giardano at al. 1998
Kashef et al.2008
Hemostatic parameters in thalassemiaAssay -TM -TI
Platelet Life spanAggregationUrinary TXA2Circulating platelet aggregatesCD62, CD63PF3PF4, -TG
ShortImpairedHighPresentHighHighHigh
ShortImpairedHighPresentHighHighHigh
Vascular endothelium
ThrombomodulinICAM-1VCAM-1VWFE-selectinUrinary PGI2
HighHighHigh HighHighHigh
HighHighHigh HighHighHigh
RBC Annexin V bindingThrombin generation
IncreasedIncreased
IncreasedIncreased
Coagulation factors
Factor IIFactors V, VII, X
LowNormal
LowNormal
Coagulation inhibitors
Protein C (antigen, activity)Protein S (free)ATIIIHCII
LowLowNormalLow
LowLowLow
Thrombin generation
TATF1,2FPAD-dimer
HighNormal
HighHighHighHigh
Eldor A and Rachmilewitz EA. Blood 2002; 99(1): 36-43
PATHOGENESIS
Factors contributing to the hypercoagulable state in thalassemia
Hypercoagulable State
Red Blood CellsAbnormal erythroid cellsSource of procoagulant phospholipidsEnhanced cohesiveness
Iron overloadHyperviscosityEndothelial damageMonocyte activationRelease of microparticles
Genetic mutationsFactor V LeidenProthrombin G20210MTHFR C677T(hyperhomocysteinemia)? Others
Cardiac dysfunctionLiver dysfunctionHormonal deficienciesAntiphospholipid antibodies? Intravascular hemolysis
Decreased levels ofProtein CProtein SAntithrombin III
PlateletsIncreased platelet aggregationState of oxidative stress (ROS)Expression of activation markers (CD62P and CD63)
Taher et al. Blood Reviews 2008; 22: 283-292
Thrombophilic DNA mutations Genetic basis for the hypercoagulable state in thalassemia patients is not clear.
Eldor et al. (1999)No increased prevalence of FVL, PT20210 A, MTHFR C 677 T mutations.
Finkelstein et al. (2004)(5/23) had spesific mutations
Finkelstein et al. Pediatr Hematol Oncol 2004
Zalloua et al. (2003)14% were heterozygous for FVL
Genetic Mutations
FVL (heterozygous) 8/48 (17%)FVL (homozygous) 1/48 (2%)PT20210A mutation 1/48 (2%)
(heterozygous) Normal population (in Turkiye) FVL 10.4 % PT 20210A 2.7 %
Sipahi T et al. Clin Appl Thromb Hemost 2008
Genetic Mutations Sipahi et al.
Distribution of PT20210 G-A Polymorphism in Patients and Controls
Genotype n (%) G/G (%) GA (%) p ORControl 70 (100) 68 (97) 2 (3) 1 1.38 (0.1217-15.697 ) Patients 48 (100) 47 (98) 1 (2)
Sipahi T et al. Clin Appl Thromb Hemost 2008
Genotype n (%) G/G (%) GA (%) AA (%) p ORControl 70 (100) 60 (86) 10 (14) 0 (0) 0.795 0.81 (0.29-2.24)
Patients 48 (100) 39 (87) 8 (17) 1 (2)
Distribution of FV1691 G-A Polymorphism in Patients and Controls
Genetic Mutations Sipahi et al.
Distribution of MTHFR 677C-T Polymorphism in Patients and Controls
Genotype n (%) C/C (%) CT (%) T/T (%) p ORControl 70 (100) 37 (52.9) 29 (41.4) 4 (5.7) 0.24 0.59 (0.28-1.28)Patient 48 (100) 19 (40) 25 (52) 4 (8) 0.44 0.51 (0.12-2.28)
Sipahi T et al. Clin Appl Thromb Hemost 2008
Distribution of Elevated sEPCR Levels in Patients and Control
EPCR level n (%) Normal (%) Elevated (%) p ORControl 61 (100) 46 (75.4) 12 (24.6) 0.34 1.68 (0.62-4.55)Patient 43 (100) 38 (88.4) 5 (11.6)
Genetic Mutations Sipahi et al.
Result of our study was, significant decrements of protein C and protein S and slight increased prevalence of congenital thrombophilic mutations when compared to controls. Although five of the patients had high sEPCR levels, no significant change was found at sEPCR values between patients and controls.
Sipahi T et al. Clin Appl Thromb Hemost 2008
Genetic Mutations Sipahi et al.
Other Factors
Other pathogenetic mechanisms:Congestive heart failure
Cardiac dysfunction
Liver dysfunction
Hormonal deficiencies
Prevention of thromboembolism The TE events in the majority of patients are usually manifested in the second or third decade of life
Post transf. Hb should not exceed 15g
Effective iron chelation should be initiated after 10-20 transfusions when serum ferritin exceeds 1000 µg/L
Low dose aspirin can be given in splenectomized patients with platelet counts above 800 000/dl
The management of TE events:– LMWH (enoxaparin, dalteparin, nadroparin)
7 days Dose: 1 mg/kg twice a day sc
– Warfarin (long term)
Prophylaxis for TE in thalassemia– Antiplatelet agents– Hydroxyurea– Aspirin– Antioxidants
Prevention of thromboembolism
Even if thromboembolic complications could be explained by hypercoagulable state found in thalassemia major patients; following the first thrombotic event, should be investigated for congenital thrombophilia.When they are exposed to thrombotic risk factors such as immobilisation, surgery and delivery, prophylactic antithrombotic agents may be recommended.
In Conclusion