Splenectomy and thrombosis: the case of thalassemia intermedia

Non-Transfusion-Dependent Thalassaemia: A Panoramic Survey from Pathophysiology to Treatment

Non-transfusion-dependent thalassaemia (NTDT) is a rather broad term that encompasses a group of thalassaemia syndromes, most commonly β-thalassaemia intermedia, haemoglobin E/β-thalassemia, and α-thalassaemia intermedia (haemoglobin H disease). Importantly, these entities do not require regular blood transfusions for survival, and therefore have transfusion independence. Clinical morbidities associated with the NTDTs are the end result of the culmination of three principal pathophysiological aberrancies: ineffective erythropoiesis, chronic anaemia (and associated haemolysis), and iron overload. Such complications involve multiple organs and organ systems; hence, the importance of prompt identification of at-risk individuals and holistic management of diagnosed subjects can never be overstated. Several management options, both medical and surgical, remain at the disposal of involved clinicians, with a significant body of data favouring the virtue of iron chelation therapy, fetal haemoglobin induction, and treatment with blood transfusions, the latter only when absolutely indicated, with reservation of splenectomy to a few select cases. Yet, a better understanding of the molecular phenomena at the origin of the disease process in the NTDT syndromes calls for a pressing need to explore novel therapeutic modalities, in light of the increasing incidence of NTDT in the developed world.

Microparticles from splenectomized β-thalassemia/HbE patients play roles on procoagulant activities with thrombotic potential

Thromboembolic events including cerebral thrombosis, deep vein thrombosis, and pulmonary embolism are major complications in β-thalassemia. Damaged red blood cells and chronic platelet activation in splenectomized β-thalassemia/HbE patients were associated with increased microparticles (MPs) releases into blood circulation. MPs are small membrane vesicles, which play important roles on coagulation. However, the role of MP in thalassemia is poorly understood. In this study, the effects of splenectomized-MPs on platelet activation and aggregation were investigated. The results showed that isolated MPs from fresh platelet-free plasma of patients and normal subjects directly induce platelet activation, platelet aggregation, and platelet-neutrophil aggregation in a dose-dependent manner. Interestingly, MPs obtained from splenectomized patients are more efficient in induction of platelet activation (P-selectin⁺) when compared to MPs from normal subjects (P < 0.05), tenfold lower than pathophysiological level, at 1:0.1 platelet MP ratio. Co-incubation of splenectomized-MPs with either normal-, non-splenectomized- or splenectomized-platelets at 1:10 platelet MP ratio increased platelet activation up to 5.1 ± 2.2, 5.6 ± 3.7, and 9.5 ± 3.0%, respectively, when normalized with individual baseline. These findings suggest that splenectomized patients were proned to be activated by MPs, and splenectomized-MPs could play an important role on chronic platelet activation and aggregation, leading to thrombus formation in β-thalassemia/HbE patients.

Morbidity and mortality of adult patients with congenital dyserythropoietic anemia type I

Congenital dyserythropoietic anemia type I (CDAI) is a rare autosomal recessive disease characterized by macrocytic anemia, ineffective erythropoiesis, and secondary hemochromatosis. To better define the natural history of the disease among adult patients, we studied 32 Bedouin patients (median age 34 yr; range 21-60) all carrying the same CDAN1 founder mutation. Follow-up studies included complete blood count, blood chemistry, abdominal ultrasound, echocardiography, and T2*MRI. Main complications were due to anemia and ineffective erythropoiesis [osteoporosis (8/9, 89%), cholelithiasis (21/30, 70%), pulmonary arterial hypertension (PAH) (6/25, 24%)] and iron overload [hypothyroidism (9/24, 38%), and diabetes mellitus (6/32, 19%)]. T2* MRI revealed increased liver iron but no cardiac iron (13/13). Anemia improved in the majority of patients who underwent splenectomy (5/6). Three patients died (9%) at the age of 46-56 due to PAH (1) and sepsis (2). All previously underwent splenectomy. Analyzing both our patients and the 21 patients previously described by Heimpel et al. (Blood 107:334, 2006), we conclude that adults with CDA I suffer significant morbidity and mortality. Careful monitoring of iron overload and prompt iron chelation therapy is mandatory. Due to possible complications and inconsistent response to splenectomy α-interferon, transfusion therapy or stem cell transplantation should be considered as alternatives to this procedure in severely affected patients.

Prevalence and Risk Factors for Complications in Patients with Nontransfusion Dependent Alpha- and Beta-Thalassemia

Background. Nontransfusion dependent thalassemia (NTDT) is a milder form of thalassemia that does not require regular transfusion. It is associated with many complications, which differ from that found in transfusion-dependent thalassemia (TDT). Currently available information is mostly derived from beta-NTDT; consequently, more data is needed to describe complications found in the alpha-NTDT form of this disease. Methods. We retrospectively reviewed the medical records of NTDT patients from January 2012 to December 2013. Complications related to thalassemia were reviewed and compared. Results. One hundred patients included 60 females with a median age of 38 years. The majority (54 patients) had alpha-thalassemia. Overall, 83 patients had one or more complications. The three most common complications were cholelithiasis (35%), abnormal liver function (29%), and extramedullary hematopoiesis (EMH) (25%). EMH, cardiomyopathy, cholelithiasis, and pulmonary hypertension were more commonly seen in beta-thalassemia. Osteoporosis was the only complication that was more common in alpha-thalassemia. The risk factors significantly related to EMH were beta-thalassemia type and hemoglobin < 8 g/dL. The risk factors related to osteoporosis were female gender and age > 40 years. Iron overload (ferritin > 800 ng/mL) was the only risk factor for abnormal liver function. Conclusion. The prevalence of alpha-NTDT complications was lower and different from beta-thalassemia.

The frequency of silent cerebral ischemia in patients with transfusion-dependent β-thalassemia major

The aim of this study is to determine the frequency of silent cerebral ischemia (SCI) in a group of patients with β-thalassemia major and correlate them with demographic parameters, blood and spleen status, volume and frequency of transfusions. In this cross-sectional study, 40 β-thalassemic patients over 10 years old who had no neurologic deficit were studied. Brain MRI was performed to detect SCI. Silent cerebral ischemia was classified according to number and size. Silent cerebral ischemia was found in 15 patients (37.5 %). Mean number of SCI was 6.73 ± 10.33 (1-40), and mean size of the brain lesions was 3.07 ± 2.81 mm (1-11 mm). The patients with SCI were significantly older (31.1 ± 6.5 vs. 25 ± 6.8 years, P = 0.009), and most of them were splenectomized (80% vs. 36 %, P = 0.01). Interestingly, 10 out of 15 patients with SCI had platelet count less than 500,000/mm(3). Eight of these patients (80 %) were splenectomized. Other variables had no statistically significant association with the presence of SCI. Older age and splenectomized multitransfused β-thalassemic patients even with normal platelet count have a higher incidence of SCI. The effect of splenectomy is more significant in statistical analysis. In splenectomized patients with a high platelet count and even with normal platelet count, aspirin therapy is indicated. Based on the results, it seems that regular blood transfusions are not going to have a significant effect on the number and size of SCI.

Priapism, an emerging complication in β-thalassemia intermedia patients

The increase in survival rate of β-thalassemia (β-thal) patients allowed for the appearance and manifestation of several complications in almost every organ system. Priapism in β-thal patients is rarely reported in the literature. We herein report and investigate the occurrence of two cases of priapism in two young patients with β-thal intermedia (β-TI). The potential mechanisms are due to either a cellular mechanism involving a thrombus obstructing the efferent venules of the corpora cavernosa leading to priapism, or a recently elucidated functional mechanism that causes alteration of nitric oxide (NO) response of the penis, ultimately causing priapism. This should incite clinicians for a close follow-up and monitoring of high risk patients who are susceptible to developing priapism.

Coagulopathy and functional hyposplenism during an episode of thrombotic thrombocytopenic purpura in a HgbS/β (+)-thalassemia patient

We report a case of TTP in a sickle cell/β+-thalassemia heterozygote with nonspecific complaints and a evidence of hemolysis, initially attributed to sickle crisis. Included in this case is a discussion of the development of functional hyposplenism, a rarely reported complication, limitation of ADAMTS-13 in diagnosis, and the use of platelet transfusion.

Platelet Aggregation Study in Patients With Hemoglobin Eβ Thalassemia in India

Hemoglobin Eβ thalassemia is a major public health problem in India, especially in the state of West Bengal. Various thromboembolic events are common, especially in splenectomized patients. Platelet hyperactivity most likely plays a pathogenetic role. To investigate the role of platelets in hypercoagulability, platelet aggregation tests were undertaken in the present study. Platelet-rich plasma from 30 patients with Eβ thalassemia (15 splenectomized and 15 nonsplenectomized) were studied and compared with 15 healthy participants. The 4 agonists used were adenosine 5-diphosphate, adrenaline (epinephrine), collagen, and ristocetin. The current study shows both splenectomized and nonsplenectomized patients had abnormal aggregation compared to normal healthy controls. Splenectomized patients had higher platelet aggregation than nonsplenectomized patients for all 4 agonists; but statistically significant difference among 2 groups was found only for collagen. The present study confirms a role of splenic absence in platelet hyperaggregation.

When to consider transfusion therapy for patients with non-transfusion-dependent thalassaemia

Non-transfusion-dependent thalassaemia (NTDT) refers to all thalassaemia disease phenotypes that do not require regular blood transfusions for survival. Thalassaemia disorders were traditionally concentrated along the tropical belt stretching from sub-Saharan Africa through the Mediterranean region and the Middle East to South and South-East Asia, but global migration has led to increased incidence in North America and Northern Europe. Transfusionists may be familiar with β-thalassaemia major because of the lifelong transfusions needed by these patients. Although patients with NTDT do not require regular transfusions for survival, they may require transfusions in some instances such as pregnancy, infection or growth failure. The complications associated with NTDT can be severe if not properly managed, and many are directly related to chronic anaemia. Awareness of NTDT is important, and this review will outline the factors that should be taken into consideration when deciding whether to initiate and properly plan for transfusion therapy in these patients in terms of transfusion interval and duration of treatment.

Non-Transfusion Dependent Thalassemia: Translating Evidence to Guidelines

The thalassemias are a group of inherited disorders of hemoglobin synthesis characterized by various degrees of defective production of the α- or β-globin chains of adult hemoglobin A. Non-transfusion- dependent thalassemia (NTDT) includes a group of thalassemia patients who do not require regular RBC transfusions for survival, but may require occasional transfusions due to infection or pregnancy or may require more regular transfusions later in life due to splenomegaly or other complications. Due to the rising phenomenon of global migration, this previously well-localized entity is currently spreading more and more worldwide reaching Northern America and Northern Europe. The clinical picture of NTDT is governed by the severity of the ineffective erythropoiesis and the chronic hemolytic anemia, which, in turn, lead to iron overload, hypercoagulability, and an array of clinical complications involving almost every organ system. Patients with NTDT suffer from complications that are distinct from those encountered in patients with transfusion- dependent thalassemia (TDT) in addition to the complications shared by both TDT and NTDT. As a consequence, patients with NTDT deserve a care specifically tailored to their needs. In the care of patients with NTDT, aiming at a standardized yet personalized care is not an easy task especially that NTDT patients lie on a heterogeneous spectrum with a wide variability in their clinical presentation and response to therapy. Therefore, guidelines emerge as a necessity to answer the specific needs of NTDT patients and the clinicians caring for them. In this article, we summarize the complications most commonly associated with NTDT and the recommendations of the guidelines for the management of patients with NTDT, based on the best available evidence.

Guidelines for diagnosis and management of Beta-thalassemia intermedia

Beta-thalassemia intermedia (β-TI) is a genetic variant of beta-thalassemias with a clinical disorder whose severity falls between thalassemia minor and thalassemia major. Different genetic defects are involved in this disorder and, based on severity of disease, clinical complications like skeletal deformities and growth retardation, splenomegaly, extramedullary hematopoiesis, heart failure, and endocrine disorders may be present in untreated patients. Precise diagnosis and management are essential in these patients for prevention of later clinical complications. Diagnosis of TI is based on clinical and laboratory data. There are some treatment strategies like modulation of gamma-globulin chain production with hydroxyurea or other drugs, transfusion, splenectomy, and stem cell transplantation. Iron chelation therapy is also needed in many of these patients even if they are not transfused. The aim of this manuscript is to review the clinical manifestations, complications, genetic defects, and unmet treatments needs in TI.

Identification and key management of non-transfusion-dependent thalassaemia patients: not a rare but potentially under-recognised condition

Patients with non-transfusion-dependent thalassaemia (NTDT) have a genetic defect or combination of defects that affect haemoglobin synthesis, but which is not severe enough to require regular blood transfusions. The carrier frequency of NTDT is high (up to 80% in some parts of the world) but the prevalence of symptomatic patients varies with geography and is estimated to be from 1 in 100,000 to 1 in 100. NTDT has a variable presentation that may include mild to severe anaemia, enlarged spleen and/or liver, skeletal deformities, growth retardation, elevated serum ferritin and iron overload. The contributing factors to disease progression are ineffective erythropoiesis and increased haemolysis, which lead to chronic anaemia. The body's attempts to correct the anaemia result in constantly activated erythropoiesis, leading to marrow expansion and extramedullary haematopoiesis. Diagnosis of NTDT is largely clinical but can be confirmed by genetic sequencing. NTDT must be differentiated from other anaemias including sideroblastic anaemia, paroxysmal nocturnal haemoglobinuria, congenital dyserythropoietic anaemia, myelodysplastic syndromes and iron-deficiency anaemia. Management of NTDT is based on managing symptoms, and includes blood transfusions, hydroxyurea treatment, iron chelation and sometimes splenectomy. Prognosis for well managed patients is good, with most patients living a normal life. Since NTDT is mainly prevalent in sub-tropical regions, patients who present in other parts of the world, in particular the Northern hemisphere, might not been correctly recognised and it can be considered a 'rare' condition. It is particularly important to identify and diagnose patients early, thereby preventing complications.

Splenectomy improves anaemia but does not reduce iron burden in patients with haemoglobin H Constant Spring disease

BACKGROUND

Splenectomy is reported to increase the haemoglobin level in patients with haemoglobin H Constant Spring (HbH CS) disease; however, its impact on iron burden and the underlying mechanism remains unclear.

MATERIALS AND METHODS

From March through to May 2013, a total of 50 adults with HbH CS disease (25 cases splenectomised and 25 cases non-splenectomised) were enrolled. The patients' general conditions, history of blood transfusion and iron chelator treatment were investigated. Levels of haemoglobin, nucleated red blood cell counts, and serum ferritin were measured. The percentage of apoptotic erythroid precursor cells in bone marrow, an index representing ineffective erythropoiesis, was determined in some cases.

RESULTS

There were no significant differences in age, blood transfusion volume, and use of iron chelator drugs between the splenectomised group and the non-splenectomised group. Significantly higher haemoglobin levels, serum ferritin levels and nucleated red blood cell counts as well as a higher percentage of apoptotic erythroid progenitor cells were detected in the splenectomised group. Regression analysis revealed that age and nucleated red blood cell counts were independent risk factors affecting the serum ferritin level.

DISCUSSION

Despite improving the haemoglobin level, splenectomy is associated with greater iron burden in HbH CS disease. A high nucleated red blood cell count is predictive of the risk of severe iron overload.

Elevated tricuspid regurgitant jet velocity in subgroups of thalassemia patients: insight into pathophysiology and the effect of splenectomy

A high tricuspid regurgitant jet velocity (TRV) signifies a risk for or established pulmonary hypertension (PH), which is a serious complication in thalassemia patients. The underlying pathophysiology in thalassemia subgroups and potential biomarkers for early detection and monitoring are not well defined, in particular as they relate to spleen removal. To better understand some of these unresolved aspects, we examined 76 thalassemia patients (35 non-transfused), 25 splenectomized non-thalassemia patients (15 with hereditary spherocytosis), and 12 healthy controls. An elevated TRV (>2.5 m/s) was found in 25/76 (33 %) of the patients, confined to non-transfused or those with a late start of transfusions, including patients with hemoglobin H-constant spring, a finding not previously described. These non or late-transfused patients (76 % splenectomized) had significantly increased platelet activation (sCD40L), high platelet count, endothelial activation (endothelin-1), and hemolysis (LDH, plasma-free Hb), while hypercoagulable and inflammatory markers were not significantly increased. The same markers were increased in the seven patients with confirmed PH on cardiac catheterization, suggesting their possible role for screening patients at risk for PH. A combination of hemolysis and absence of spleen is necessary for developing a high TRV, as neither chronic hemolysis in the non-splenectomized thalassemia patients nor splenectomy without hemolysis, in the non-thalassemia patients, resulted in an increase in TRV.

β -thalassemia intermedia in Northern Iraq: a single center experience

To investigate the molecular basis of β-thalassemia intermedia in Northern Iraq and evaluate its management practices, a total of 74 patients from 51 families were enrolled. The patients were clinically and hematologically reevaluated, and had their β-thalassemia mutations characterized, as well as the number of α-globin genes and Xmn I ^Gγ −158 (C>T) polymorphism studied. Out of 14 β-thalassemia mutations identified, the four most common were IVS-I-6 (T>C) [33.3%], IVS-II-I (G>A) [21.1%], codon 82/83(−G) [10.1%], and codon 8 (−AA) [8.1%]. The most common contributing factors to the less severe phenotype of thalassemia intermedia were found to be the inheritance of mild β-thalassemia alleles and the Xmn I polymorphism, while concomitant α-thalassemia had a limited role. Several complications were documented including: pulmonary hypertension in 20.4%, diabetes mellitus in 1.4%, hypothyroidism in 2.9%, and heart failure in 2.7%, while no documented cases of venous thrombosis were found. Compared to their counterparts in several Mediterranean countries, it appears that our patients were much less frequently transfused and had a lower proportion of patients who were splenectomized, on iron chelation, or hydroxycarbamide therapy. Such practices require further scrutiny to ensure that a better level of care is provided and that growth retardation, skeletal changes, and other complications are prevented or reduced.

Non-transfusion-dependent thalassemias

Non-transfusion-dependent thalassemias include a variety of phenotypes that, unlike patients with beta (β)-thalassemia major, do not require regular transfusion therapy for survival. The most commonly investigated forms are β-thalassemia intermedia, hemoglobin E/β-thalassemia, and α-thalassemia intermedia (hemoglobin H disease). However, transfusion-independence in such patients is not without side effects. Ineffective erythropoiesis and peripheral hemolysis, the hallmarks of disease process, lead to a variety of subsequent pathophysiologies including iron overload and hypercoagulability that ultimately lead to a number of serious clinical morbidities. Thus, prompt and accurate diagnosis of non-transfusion-dependent thalassemia is essential to ensure early intervention. Although several management options are currently available, the need to develop more novel therapeutics is justified by recent advances in our understanding of the mechanisms of disease. Such efforts require wide international collaboration, especially since non-transfusion-dependent thalassemias are no longer bound to low- and middle-income countries but have spread to large multiethnic cities in Europe and the Americas due to continued migration.

Thalassemia and the hypercoagulable state

Thalassemia, an inherited hemolytic disorder, is associated with a high incidence of thrombosis. The major mechanisms underlying thromboembolism (TE) are an abnormal red blood cell surface, platelet activation and endothelial cell activation. A higher risk of TE is found in splenectomized patients due to thrombocytosis and increased abnormal RBCs in the circulation. Regular RBC transfusions can reduce the proportion of abnormal RBCs and suppress erythropoiesis. Regular transfusion may also reduce levels of circulating coagulation markers and reduce elevated pulmonary artery pressure. To prevent thromboembolic events, aspirin is now recommended for splenectomized patients with thrombocytosis.

Thalassemic erythrocytes release microparticles loaded with hemichromes by redox activation of p72Syk kinase

High counts of circulating microparticles, originated from the membrane of abnormal erythrocytes, have been associated with increased thrombotic risk in hemolytic disorders. Our studies indicate that in thalassemia intermedia patients the number of circulating microparticles correlates with the capability of the thalassemic erythrocytes to release microparticles. The microparticles are characteristically loaded with hemichromes formed by denatured α-chains. This finding was substantiated by the positive correlation observed in thalassemia intermedia patients between the amount of hemichromes measured in erythrocytes, their capability to release microparticles and the levels of plasma hemichromes. We observed that hemichromes, following their binding to the cytoplasmic domain of band 3, induce the formation of disulfide band 3 dimers that are subsequently phosphorylated by p72Syk kinase. Phosphorylation of oxidized band 3 appears to be relevant for the formation of large hemichromes/band 3 clusters that, in turn, induce local membrane instability and the release of microparticles. Proteomic analysis of microparticles released from thalassemia intermedia erythrocytes indicated that, besides hemichromes and clustered band 3, the microparticles contain a characteristic set of proteins that includes catalase, heat shock protein 70, peroxiredoxin 2 and carbonic anhydrase. High amounts of immunoglobulins and C3 have also been found to be associated with microparticles, accounting for their intense phagocytosis. The effect of p72Syk kinase inhibitors on the release of microparticles from thalassemia intermedia erythrocytes may indicate new perspectives for controlling the release of circulating microparticles in hemolytic anemias.

Cerebral Artery Velocity Determined by Transcranial Doppler Ultrasonography in Patients With β-Thalassemia Intermedia Compared to β-Thalassemia Major

We aimed to compare cerebral artery velocity and relevant clinical factors in patients with β-thalassemia intermedia (β-TI), β-thalassemia major (β-TM), and healthy individuals. For this study, 60 patients with β-TM and 64 with β-TI were randomly selected. Sixty healthy adults comprised the control group. Time average maximum mean velocity (TAMMV) was measured in large cerebral arteries with transcranial Doppler (TCD) ultrasonography. In all arteries, TAMMV was significantly higher in the β-TI group than that of β-TM or controls ( P < .001). Patients with β-TM had significantly higher TAMMV than controls in most arteries evaluated ( P < .001). Overall, the lack of regular blood transfusions, splenectomy, and lower age (to a lesser extent) was found to be independent influencing factors contributing to high cerebral artery velocities. Further detailed longitudinal studies are needed to confirm these results and to determine the risk of silent infarction and stroke in patients with thalassemia and abnormal TCD, with particular focus on patients with β-TI.

Pulmonary hypertension risk in patients with hemoglobin h disease: low incidence and absence of correlation with splenectomy

Pulmonary hypertension (PHT) is a common complication for patients with β thalassemia intermediate (TI), especially splenectomized patients. However, the frequency and risk factors of PHT in patients with hemoglobin H (HbH) disease is unknown. The purpose of this study was to identify the prevalence of PHT risk manifested as tricuspid regurgitant jet velocity (TRV) ≥2.5 m/s in patients with HbH disease and its correlation with splenectomy. One hundred and ninety-eight patients with HbH disease who visited the 303rd Hospital of the People's Liberation Army (Nanning, China) were investigated. Thirteen subjects (6.5%) were diagnosed as having a risk of PHT. Regression analyses showed that the prevalence of PHT risk was correlated only with age (r = 0.195, p = 0.006) and not with splenectomy. The risk of PHT in patients older than 35 years was 5.7 times (range 1.8-18.6) greater than that for patients younger than 35 years. For splenectomized patients compared to those with HbH disease, patients with TI had a higher frequency of PHT risk, higher nucleated red blood cell counts (46.03 ± 41.11 × 10(9)/l vs. 0.18 ± 1.19 × 10(9)/l, p < 0.001) and a higher platelet counts (837.6 ± 178.9 × 10(9)/l vs. 506.7 ± 146.2 × 10(9)/l, p < 0.001). PHT risk is low in patients with HbH disease and does not correlate with splenectomy. Patients older than 35 years should be monitored regularly.

Cross-talk between available guidelines for the management of patients with beta-thalassemia major

Efforts to optimize the management of patients with β-thalassemia major (TM) continue to expand. Evidence from biomedical research evaluating safe and careful processing measures of blood products, the efficacy and safety of oral iron chelators, and noninvasive techniques for the assessment of iron overload are translated into better patient outcomes. The construction of TM management guidelines facilitated the incorporation of such evidence into practice. However, as several aspects of the management of TM remain controversial or governed by resource availability, a concern regarding potential variations in recommendations made by the different guidelines becomes rational, especially for physicians treating TM patients outside countries where the guidelines were constructed. In this work, we overview currently available guidelines for the management of TM and explore apparent similarities and differences between them. The evaluated guidelines included the Thalassaemia International Federation, US, Canadian, UK, Italian and Australian guidelines. We noted a general consensus for most aspects of management, although some guidelines provided more comprehensive and contemporary recommendations than others. We did not identify differences warranting concern, although minor differences in iron overload assessment strategy and more notable variations in the recommendations for iron chelation therapy were observed.

Cerebral thrombosis in patients with β-thalassemia: a systematic review

A hypercoagulable state has been documented in patients with β-thalassemia. It could result in thromboembolic events in several organs including brain involvement, which deserves particular attention. We summarized the prevalence of cerebral involvement in patients with β-thalassemia worldwide. We conducted an electronic search on PUBMED (MEDLINE), SCOPUS, and Google Scholar databases up to January 2011. Overall 152 thalassemic patients with cerebral thromboembolic events and a proportion of 1.13% (134 of 11770) were recorded. From all patients with cerebral thromboembolic events, 74 (48%) were splenectomized. Cerebral thromboembolic events were reported after transfusion in six β-thalassemia major, and two β-thalassemia intermedia patients. Three β-thalassemia major patients had irregular transfusion and 22 β-thalassemia intermedia patients were not transfused. Thrombocytosis were determined in 11 β-thalassemia major, and 15 β-thalassemia intermedia patients. Cardiomyopathy was present in 13 β-thalassemia major and four β-thalassemia intermedia patients. Also, nine β-thalassemia major patients had diabetes. Activated protein C resistant, decreased protein C or protein S or plasminogen level was detected in eight β-thalassemia major patients. Cerebral involvement appears to be associated with increasing age, transfusion naivety, splenectomy, thrombocytosis, intensive transfusion, decreased protein C level, and having risk factors for cerebrovascular accident such as cardiomyopathy, and diabetes. In light of these findings, diagnostic MRI is recommended in high-risk groups to screen for early asymptomatic brain damage. If brain ischemia is found, the administration of antiplatelet aggregants or blood transfusion is likely to be beneficial. In addition, in thalassemic patients who complicated with a thromboembolic event, secondary prophylaxis could be helpful to prevent cerebral thromboembolic events.

Glomerular hyperfiltration and proteinuria in transfusion-independent patients with β-thalassemia intermedia

BACKGROUND/AIMS

Renal manifestations have been described in β-thalassemia major and were attributed to transfusional iron overload and chelation therapy. Patients with the milder phenotype, β-thalassemia intermedia (TI), remain largely transfusion and iron chelation independent while enduring a chronic hemolytic anemia and primary iron overload. Data on renal function in patients with TI is lacking.

METHODS

In this cross-sectional study of 50 TI patients, we evaluated the association of estimated glomerular filtration rate (eGFR) and urinary protein to creatinine (UPr/UCr) ratio with relevant patient, disease and laboratory indices.

RESULTS

The median age of patients was 28 years (44% males). The eGFR was >90 ml/min/1.73 m(2) in all patients, with a median value of 142.3 ml/min/1.73 m(2). The median UPr/UCr ratio was 213.2 mg/g. There was a negative correlation between age and eGFR, while the UPr/UCr ratio correlated positively with markers of anemia, hemolysis and iron overload. A total of 24 (48%) patients had evidence of glomerular hyperfiltration, while 7 (14%) had proteinuria (UPr/UCr ratio >500 mg/g). Patients with proteinuria were characterized by elevated liver iron concentration (>7 mg Fe/g dry weight), non-transferrin-bound iron levels and nucleated red blood cell counts.

CONCLUSIONS

A considerable proportion of TI patients show evidence of abnormally elevated eGFR, with a declining trend towards advancing age. The occurrence of proteinuria is associated with anemia, hemolysis and iron toxicity.

β-thalassemia intermedia: a clinical perspective

Our understanding of the molecular and pathophysiological mechanisms underlying the disease process in patients with β-thalassemia intermedia has substantially increased over the past decade. Earlier studies observed that patients with β-thalassemia intermedia experience a clinical-complications profile that is different from that in patients with β-thalassemia major. In this article, a variety of clinical morbidities are explored, and their associations with the underlying disease pathophysiology and risk factors are examined. These involve several organs and organ systems including the vasculature, heart, liver, endocrine glands, bone, and the extramedullary hematopoietic system. The effects of some therapeutic interventions on the development of clinical complications are also discussed.

Short- and long-term risks of splenectomy for benign haematological disorders: should we revisit the indications?

Splenectomy has represented a key treatment option in the treatment of many benign haematological diseases, including immune thrombocytopenia (ITP) and disorders associated with ongoing haemolysis (thalassaemia major and intermedia, sickle cell disease, and hereditary or acquired haemolytic anaemias). Improvements in surgical techniques have reduced perioperative complications and mortality. Preventive measures (new protein conjugate vaccines, antibiotic prophylaxis, and increased vigilance) are thought to greatly reduce the risk of overwhelming post-splenectomy infection (OPSI), although their implementation is inconsistent. Nevertheless, there is increasing documentation of the short- and long-term risks of splenectomy, which vary according to the underlying indication. Splenectomized patients are at increased risk of venous thromboembolism, particularly within the splenoportal system. The long-term thromboembolic risk is higher in haematological disorders associated with ongoing haemolysis, particularly in thalassaemia intermedia, which has led to a more conservative approach. In comparison, patients with ITP appear to be at lower risk of adverse effects of splenectomy, which maintains its place as the potentially most curative and safe second-line treatment. However, a splenectomy-sparing approach is also emerging for ITP, and recent guidelines recommend that this procedure is deferred until ≥ 12 months from ITP diagnosis, to allow sufficient time for possible remission.

D-dimer and portal vein status in splenectomized Egyptian β-thalassemia major patients: a prospective single-thalassemia center experience

Splenectomy is a recognized cause of portal vein thrombosis. Thirty-six β-thalassemia major (β-TM) patients were followed up for 36 months to evaluate changes in D-dimer levels (as a possible marker for thrombosis development) and portal vein status (by portal duplex ultrasound) at both early and late postlaparoscopic splenectomy periods. They were classified into group I if they were splenectomized in the study period (n = 12), or group II if they were splenectomized during the 5 years preceding the period (n = 24). In group I, D-dimer was measured 5 times: 1 day presplenectomy, the 1st week, 6th week, and 6th month postsplenectomy, and at the study end, whereas in group II, D-dimer was measured twice: at the study entry and end. Portal duplex was done 1 week postsplenectomy (group I) and at study end in both groups. Presplenectomy D-dimer levels in group I were significantly higher compared with the 6th month (P = .042) and study end (P = .03), whereas 1st week (postsplenectomy) D-dimer levels had a high mean of 3497.3 ng/mL, lowered at the 6th week (P = .017), at the 6th month (P = .008), and at study end (P = .005). D-dimer levels in group II showed no difference between study entry and end (P = .104). Portal vein "diameter and flow" were within normal findings in both groups. In this 3-year prospective study, a subclinical hypercoagulable state was detected 1 day prior to splenectomy and in the early postsplenectomy period, as evidenced by high D-dimer levels. Laparoscopic splenectomy was not associated with portal venous thrombosis either clinically or by duplex sonography.

Brain magnetic resonance angiography in splenectomized adults with β-thalassemia intermedia

BACKGROUND

 Hypercoagulability and venous thromboembolism are common in patients with β-thalassemia intermedia (TI), especially in the splenectomized adult. Although arterial involvement is not commonly reported, we have recently observed a high prevalence (60%) of silent brain infarction on brain MRI in 30 splenectomized adults with TI. The pathophysiology of these white matter lesions remains unknown.

METHODS

In this prospective work, we evaluated magnetic resonance angiography (MRA) scans of the same cohort of 30 patients. Data collected were the presence or absence of vascular lesions, their locations, and severity. Correlations between MRA abnormality and patients/disease characteristics were evaluated. Comparisons between MRA and previous MRI findings were made.

RESULTS

Of 29 evaluable patients, 8 (27.6%) had evidence of arterial stenosis on MRA. The majority of lesions had mild narrowing and mostly involved the internal carotid artery. Five patients (17.2%) had evidence of aneurysms. Low total hemoglobin and high non-transferrin-bound iron levels independently characterized patients with evidence of stenosis on MRA. Among the 18 patients with silent brain infarction on MRI, three had evidence of stenosis on MRA with only one patient having lesions that could explain the silent infarcts.

CONCLUSIONS

Cerebral vasculopathy is common in splenectomized adults with TI. However, large-vessel disease does not explain the occurrence of silent brain infarction. The combined use of MRA and MRI better identifies splenectomized TI adults with neuroimaging abnormalities.

Risk factors for pulmonary hypertension in patients with β thalassemia intermedia

BACKGROUND

Pulmonary hypertension (PHT) is a common yet poorly understood complication of β thalassemia intermedia (TI).

METHODS

We herein evaluated risk factors for PHT in TI, through comparing 64 TI patients with evidence of PHT by symptomatology and echocardiography (Group I) to age- and sex-matched TI patients without PHT (Group II). Retrieved data included demographics, laboratory parameters, clinical characteristics, and received treatments that may influence PHT development; and reflected the period prior to PHT occurrence in Group I.

RESULTS

The mean age of Group I patients at development of PHT was 37.3±10.6years; with 44% being males. Among studied parameters, Group I patients were more likely to be splenectomized (4.9-times), transfusion-naive (3.5-times); hydroxyurea-naive (2.6-times), or iron chelation-naive (2.3-times); and have nucleated red blood cell count ≥300×10(6)/l (2.59-times) or a previous history of thromboembolic events (3.69-times).

CONCLUSION

TI patients who eventually develop PHT may be identified early on by being splenectomized, having high nucleated red blood cell counts and a previous history of thromboembolism. Prospective clinical trials that evaluate the efficacy, safety, and cost effectiveness of transfusion, iron chelation, and hydroxyurea therapy in preventing PHT in TI are invited.

Thrombosis in thalassemia: why are we so concerned?

Although life expectancy of thalassemia patients has markedly improved over the last few decades, patients still suffer from many complications of this congenital disease. The presence of a high incidence of thromboembolic events (TEE), mainly in β-thalassemia intermedia (β-TI), has led to the identification of a hypercoagulable state in these patients. In this review, the molecular and cellular mechanisms leading to hypercoagulability in thalassemia are highlighted, with a special focus on thalassemia intermedia being the group with the highest incidence of thrombotic events as compared to other types of thalassemia. Clinical experience and available clues on optimal management are also discussed.