Delayed adverse vascular events after splenectomy in hereditary spherocytosis

How complicated can be a case with immune thrombocytopenic purpura?: postsplenectomy arterial thrombosis

Arterial thrombus associated with the surgery can be seen in postsplenectomy cases, but there is no clear data in patients diagnosed with immune thrombocytopenic purpura (ITP). A 52-year-old female patient was admitted to the emergency department due to ecchymotic skin changes. Her initial platelet count was 6000/mm 3 ; after two courses of high dose-dexamethasone, intravenous immunoglobulin and rituximab, splenectomy was planned for the patient whose platelet count was again <40 000/mm 3 . She presented to the emergency department with complaints of pain and pallor in the right arm in the second week of follow-up. There was a mural thrombus that caused approximately 50% stenosis in the lumen at the division site in the aortic arch, proximal of the right subclavian artery. The patient's clinic was found to be associated with the presence of an aberrant right subclavian artery and postoperative thrombocytosis/inflammation after elimination other prothrombotic conditions.

New Clues to Cardiovascular Disease: Erythrocyte Lifespan

Determination of erythrocyte lifespan is an important part of the diagnosis of hemolytic diseases. Recent studies have revealed alterations in erythrocyte lifespan among patients with various cardiovascular diseases, including atherosclerotic coronary heart disease, hypertension, and heart failure. This review summarizes the progress of research on erythrocyte lifespan in cardiovascular diseases.

Long-term haematological response and maintained immunological function after laparoscopic subtotal splenectomy in patients with hereditary spherocytosis

INTRODUCTION

Subtotal or total splenectomy are recommended in severe and should be considered in intermediate forms of hereditary spherocytosis (HS). Data on laparoscopic subtotal splenectomy (LSTS) in HS patients are sparse.

METHODS

Thirty three patients with HS (median age 10.7 years (yrs), range 1.8-15.5) underwent LSTS. Baseline and follow-up investigation included haematological parameters, microscopic analysis of pitted erythrocytes (pitE), and B-cell subpopulations assessed by flow cytometry. Results were compared to those of non-splenectomised HS patients, HS patients after total splenectomy (TS), and healthy individuals.

RESULTS

After LSTS, haemoglobin levels were normalised in all patients. During median long-term follow-up of 3.9 yrs (range 1.1-14.9), only four patients presented mild anaemia. Despite re-growing of the remnant spleen none of the patients required a second surgical intervention. As compared to TS, PitE in LSTS patients were significantly lower and indicated normal to only moderately decreased spleen function. Relative but not absolute IgM memory B-cell counts were reduced in both LSTS and TS patients.

CONCLUSIONS

LSTS is effective for the treatment of patients with HS. A small remnant spleen is sufficient to provide adequate phagocytic function and to induce a pool of IgM memory B-cells.

[Splenic dysfunction in sickle cell disease: An update]

The spleen filters blood cells and contributes to the immune defense. The red pulp clears the blood from altered red blood cells via its unique microcirculatory network ; while the white pulp is a secondary lymphoid organ, directly connected to the bloodstream, whose specificity is the defense against encapsulated bacteria through the production of "natural" IgM in the marginal zone. Various health conditions can cause acquired impairment of the splenic function (or hyposplenism) directly and/or through therapeutic splenectomy. Hypo/asplenia is complicated by an increased susceptibility to encapsulated germ infections, but an increased risk of thrombosis and pulmonary hypertension has also been reported after surgical splenectomy. Homozygous sickle cell disease is the most common disease associated with functional asplenia. The latter appears early in childhood likely through repeated ischemic alterations caused by the sickling of red blood cells. In addition, specific complications such as hypersplenism and acute splenic sequestration can occur and may be life-threatening. We provide here an update on the role and physiology of the spleen, which will allow a better understanding of the pathophysiology of spleen damage and its consequences in sickle cell disease.

Diagnosis and clinical management of red cell membrane disorders

Heterogeneous red blood cell (RBC) membrane disorders and hydration defects often present with the common clinical findings of hemolytic anemia, but they may require substantially different management, based on their pathophysiology. An accurate and timely diagnosis is essential to avoid inappropriate interventions and prevent complications. Advances in genetic testing availability within the last decade, combined with extensive foundational knowledge on RBC membrane structure and function, now facilitate the correct diagnosis in patients with a variety of hereditary hemolytic anemias (HHAs). Studies in patient cohorts with well-defined genetic diagnoses have revealed complications such as iron overload in hereditary xerocytosis, which is amenable to monitoring, prevention, and treatment, and demonstrated that splenectomy is not always an effective or safe treatment for any patient with HHA. However, a multitude of variants of unknown clinical significance have been discovered by genetic evaluation, requiring interpretation by thorough phenotypic assessment in clinical and/or research laboratories. Here we discuss genotype-phenotype correlations and corresponding clinical management in patients with RBC membranopathies and propose an algorithm for the laboratory workup of patients presenting with symptoms and signs of hemolytic anemia, with a clinical case that exemplifies such a workup.

Confounding factors in the diagnosis and clinical course of rare congenital hemolytic anemias

Congenital hemolytic anemias (CHAs) comprise defects of the erythrocyte membrane proteins and of red blood cell enzymes metabolism, along with alterations of erythropoiesis. These rare and heterogeneous conditions may generate several difficulties from the diagnostic point of view. Membrane defects include hereditary spherocytosis and elliptocytosis, and the group of hereditary stomatocytosis; glucose-6-phosphate dehydrogenase and pyruvate kinase, are the most common enzyme deficiencies. Among ultra-rare forms, it is worth reminding other enzyme defects (glucosephosphate isomerase, phosphofructokinase, adenylate kinase, triosephosphate isomerase, phosphoglycerate kinase, hexokinase, and pyrimidine 5′-nucleotidase), and congenital dyserythropoietic anemias. Family history, clinical findings (anemia, hemolysis, splenomegaly, gallstones, and iron overload), red cells morphology, and biochemical tests are well recognized diagnostic tools. Molecular findings are increasingly used, particularly in recessive and de novo cases, and may be fundamental in unraveling the diagnosis. Notably, several confounders may further challenge the diagnostic workup, including concomitant blood loss, nutrients deficiency, alterations of hemolytic markers due to other causes (alloimmunization, infectious agents, rare metabolic disorders), coexistence of other hemolytic disorders (autoimmune hemolytic anemia, paroxysmal nocturnal hemoglobinuria, etc.). Additional factors to be considered are the possible association with bone marrow, renal or hepatic diseases, other causes of iron overload (hereditary hemochromatosis, hemoglobinopathies, metabolic diseases), and the presence of extra-hematological signs/symptoms. In this review we provide some instructive clinical vignettes that highlight the difficulties and confounders encountered in the diagnosis and clinical management of CHAs.

Cerebrovascular Complications of Anemia

PURPOSE OF THE REVIEW

Anemia has been called the fifth cardiovascular risk factor. It is one of the most prevalent pathologies worldwide. In this article, we aimed to perform a narrative review of the main cerebrovascular complications of anemia and its influence on stroke prognosis.

RECENT FINDINGS

Both hypoproliferative anemia (thalassemia, iron deficiency anemia, etc.) and hyperproliferative anemia (sickle cell disease, paroxysmal nocturnal hemoglobinuria, hereditary spherocytosis, etc.) are associated to cerebrovascular disease ranging from transient ischemic attack to ischemic stroke and hemorrhagic stroke with both intraparenchymal hemorrhage and subarachnoid hemorrhage or cerebral venous thrombosis. Anemia is associated to a worse prognosis in patients with cerebrovascular disease In some cases, like sickle cell disease, pathophysiological mechanisms and therapeutic guidelines are well established, while in others, due to their rarity, there are still lack of robust data. More studies are needed to clarify how the prognosis of stroke patients with anemia could be improved.

Ektacytometry Analysis of Post-splenectomy Red Blood Cell Properties Identifies Cell Membrane Stability Test as a Novel Biomarker of Membrane Health in Hereditary Spherocytosis

Hereditary spherocytosis (HS) is the most common form of hereditary chronic hemolytic anemia. It is caused by mutations in red blood cell (RBC) membrane and cytoskeletal proteins, which compromise membrane integrity, leading to vesiculation. Eventually, this leads to entrapment of poorly deformable spherocytes in the spleen. Splenectomy is a procedure often performed in HS. The clinical benefit results from removing the primary site of destruction, thereby improving RBC survival. But whether changes in RBC properties contribute to the clinical benefit of splenectomy is unknown. In this study we used ektacytometry to investigate the longitudinal effects of splenectomy on RBC properties in five well-characterized HS patients at four different time points and in a case-control cohort of 26 HS patients. Osmotic gradient ektacytometry showed that splenectomy resulted in improved intracellular viscosity (hydration state) whereas total surface area and surface-to-volume ratio remained essentially unchanged. The cell membrane stability test (CMST), which assesses the in vitro response to shear stress, showed that after splenectomy, HS RBCs had partly regained the ability to shed membrane, a property of healthy RBCs, which was confirmed in the case-control cohort. In particular the CMST holds promise as a novel biomarker in HS that reflects RBC membrane health and may be used to asses treatment response in HS.

Successful Splenectomy Management in a Patient With Moderate Factor VII Deficiency and Concomitant Severe Hereditary Spherocytosis

By the advent of the effective therapies for many coagulation diseases and hereditary spherocytosis (HS), patient's survival has been improved significantly; however, if patients are diagnosed late or left untreated, both diseases could ominously be life threatening. Concurrent occurring of factor VII (FVII) deficiency and HS is extremely rare and there is no literature report that explain this condition, thus far. In this study, we confronted a 9-year-old female patient diagnosed with HS and enlarged spleen as a result of this blood disorder. Given to her sever signs and symptoms of splenomegaly, she was candidate for emergent splenectomy. However, assessment of coagulation tests revealed a prolonged prothrombin time, suggesting the moderate FVII deficiency. With a multidisciplinary consultation, we decided to performed total splenectomy with prophylaxis administration of totally 6 doses of active recombinant FVII, initiated 1 hour before surgery and followed until 30 hours postoperation. As a result of cautious undertaken in Mofid Children's Hospital, the patient did not experience any hemostatic defect. Patient is now 14-year-old, generally well-being under regular surveillance of FVII deficiency.

Surface area-to-volume ratio, not cellular viscoelasticity, is the major determinant of red blood cell traversal through small channels

The remarkable deformability of red blood cells (RBCs) depends on the viscoelasticity of the plasma membrane and cell contents and the surface area to volume (SA:V) ratio; however, it remains unclear which of these factors is the key determinant for passage through small capillaries. We used a microfluidic device to examine the traversal of normal, stiffened, swollen, parasitised and immature RBCs. We show that dramatic stiffening of RBCs had no measurable effect on their ability to traverse small channels. By contrast, a moderate decrease in the SA:V ratio had a marked effect on the equivalent cylinder diameter that is traversable by RBCs of similar cellular viscoelasticity. We developed a finite element model that provides a coherent rationale for the experimental observations, based on the nonlinear mechanical behaviour of the RBC membrane skeleton. We conclude that the SA:V ratio should be given more prominence in studies of RBC pathologies.

Congenital Hemolytic Anemias: Is There a Role for the Immune System?

Congenital hemolytic anemias (CHAs) are a heterogeneous group of rare hereditary conditions including defects of erythrocyte membrane proteins, red cell enzymes, and disorders due to defective erythropoiesis. They are characterized by variable degree of anemia, chronic extravascular hemolysis, reduced erythrocyte life span, splenomegaly, jaundice, biliary lithiasis, and iron overload. Although few data are reported on the role of the immune system in CHAs, several immune-mediated mechanisms may be involved in the pathogenesis of these rare diseases. We reported in ~60% of patients with hereditary spherocytosis (HS), the presence of naturally-occurring autoantibodies (NAbs) directed against different membrane proteins (α- and β-spectrin, band 3, and dematin). Positive HS subjects showed a more hemolytic pattern and NAbs were more evident in aged erythrocytes. The latter is in line with the function of NAbs in the opsonization of damaged/senescent erythrocytes and their consequent removal in the spleen. Splenectomy, usually performed to reduce erythrocyte catheresis and improve Hb levels, has different efficacy in various CHAs. Median Hb increase is 3 g/dL in HS, 1.6–1.8 g/dL in pyruvate kinase deficiency (PKD), and 1 g/dL in congenital dyserythropoietic anemias (CDA) type II. Consistently with clinical severity, splenectomy is performed in 20% of HS, 45% of CDAII, and in 60% of PKD patients. Importantly, sepsis and thrombotic events have been registered, particularly in PKD with a frequency of ~7% for both. Furthermore, we analyzed the role of pro-inflammatory cytokines and found that interleukin 10 and interferon γ, and to a lesser extent interleukin 6, were increased in all CHAs compared with controls. Moreover, CDAII and enzymatic defects showed increased tumor necrosis factor-α and reduced interleukin 17. Finally, we reported that iron overload occurred in 31% of patients with membrane defects, in ~60% of CDAII cases, and in up to 82% of PKD patients (defined by MRI liver iron concentration >4 mg Fe/gdw). Hepcidin was slightly increased in CHAs compared with controls and positively correlated with ferritin and with the inflammatory cytokines interleukin 6 and interferon γ. Overall the results suggest the existence of a vicious circle between chronic hemolysis, inflammatory response, bone marrow dyserythropoiesis, and iron overload.

Clinical and laboratory outcomes following total or partial splenectomy in patients with hereditary spherocytosis

This study compared outcomes following total (TS) or partial splenectomy (PS) among patients with hereditary spherocytosis. Seventy-nine patients (TS = 33, PS = 46) were identified. The follow-up period was longer after PS (59.6 vs. 24.9 months, p < .001). Long-term adverse events occurred more frequently following PS (50% vs. 29%, p = .001). Anemia, jaundice, and fatigue recurred in six patients with PS, leading to five completion splenectomies. Hemoglobin was not different between PS and TS by 5 years post-procedure (12.3 vs. 13.4 g/dL, p = .25). Both PS and TS ameliorate symptoms and improve hematologic parameters. The rate of secondary surgery following PS should be considered when planning the initial surgical procedure.

[Hemolytic disorders and venous thrombosis: An update]

Many factors can contribute to the risk of venous thrombosis observed in hemolytic diseases. Some mechanisms are related to hemolysis by itself, while others seem more specific to each disease. Despite recent advances in the quantification of this risk and in understanding its physiopathology, the association of hemolysis with venous thrombosis is often unknown. The purpose of this general review is to clarify the main pro-thrombotic mechanisms during hemolysis and to synthesize the clinical data currently available. We will focus on the main types of hemolytic pathologies encountered in current practice, namely paroxysmal nocturnal hemoglobinuria, hemoglobinopathies, auto-immune hemolytic anemia and thrombotic microangiopathies.

Sickle cell disease, sickle trait and the risk for venous thromboembolism: a systematic review and meta-analysis

Background

Globally, sickle cell disease (SCD) is one of the most common haemoglobinopathy. Considered a public health problem, it leads to vessel occlusion, blood stasis and chronic activation of the coagulation system responsible for vaso-occlussive crises and venous thromboembolism (VTE) which may be fatal. Although contemporary observational studies suggest a relationship between SCD or sickle trait (SCT) and VTE, there is lack of a summary or meta-analysis data on this possible correlation. Hence, we propose to summarize the available evidence on the association between SCD, SCT and VTE including deep vein thrombosis (DVT) and pulmonary embolism (PE).

Methods

We searched PubMed and Scopus to identify all cross-sectional, cohort and case-control studies reporting on the association between SCD or SCT and VTE, DVT or PE in adults or children from inception to April 25, 2017. For measuring association between SCD or SCT and VTE, DVT, or PE, a meta-analysis using the random-effects method was performed to pool weighted odds ratios (OR) of risk estimates.

Results

From 313 records initially identified from bibliographic databases, 10 studies were eligible and therefore included the meta-analysis. SCD patients had significantly higher risk for VTE (pooled OR 4.4, 95%CI 2.6–7.5, p < 0.001), DVT (OR 1.1, 95% CI 1.1–1.2, p < 0.001) and PE (pooled OR 3.7, 95% CI 3.6–3.8, p < 0.001) as compared to non SCD-adults. A higher risk of VTE (OR 33.2, 95% CI 9.7–113.4, p < 0.001) and DVT (OR 30.7, 95% CI 1.6–578.2, p = 0.02) was found in pregnant or postpartum women with SCD as compared to their counterparts without SCD. Compared to adults with SCT, the risk of VTE was higher in adults with SCD (pooled OR 3.1, 95% CI 1.8–5.3, p < 0.001), and specifically in SCD pregnant or postpartum women (OR 20.3, 95% CI 4.1–102, p = 0.0003). The risk of PE was also higher in adults with SCD (OR 3.1, 95% CCI 1.7–5.9, p = 0.0004) as compared to those with SCT. The risk of VTE was higher in individuals with SCT compared to controls (pooled OR 1.7, 95% CI 1.3–2.2, p < 0.0001), but not in pregnant or postpartum women (OR 0.9, 95% CI 0.3–2.9, p = 0.863). Compared to controls, SCT was associated with a higher risk of PE (pooled OR 2.1, 95% CI 1.2–3.8, p = 0.012) but not of DVT (pooled OR 1.2, 95% CI 0.9–1.7, p = 0.157).

Conclusion

Individuals with SCD, especially pregnant or postpartum women, might have a higher risk of VTE compared to the general population. SCT might also increases the risk of VTE. However, currently available data are not sufficient to allow a definite conclusion. Further larger studies are needed to provide a definitive conclusion on the association between SCD, SCT and VTE.

Electronic supplementary material

The online version of this article (10.1186/s12959-018-0179-z) contains supplementary material, which is available to authorized users.

How I treat hypoxia in adults with hemoglobinopathies and hemolytic disorders

Hemoglobinopathies are caused by genetic mutations that result in abnormal hemoglobin molecules, resulting in hemolytic anemia. Chronic complications involving the lung parenchyma, vasculature, and cardiac function in hemoglobinopathies result in impaired gas exchange, resulting in tissue hypoxia. Hypoxia is defined as the deficiency in the amount of oxygen reaching the tissues of the body and is prevalent in patients with hemoglobinopathies, and its cause is often multifactorial. Chronic hypoxia in hemoglobinopathies is often a sign of disease severity and is associated with increased morbidity and mortality. Therefore, a thorough understanding of the pathophysiology of hypoxia in these disease processes is important in order to appropriately treat the underlying cause and prevent complications. In this article, we discuss management of hypoxia based on three different cases: sickle cell disease, β-thalassemia, and hereditary spherocytosis. These cases are used to review the current understanding of the disease pathophysiology, demonstrate the importance of a thorough clinical history and physical examination, explore diagnostic pathways, and review the current management.

Splenectomy for immune thrombocytopenia: down but not out

Splenectomy is an effective therapy for steroid-refractory or dependent immune thrombocytopenia (ITP). With the advent of medical alternatives such as rituximab and thrombopoietin receptor antagonists, the use of splenectomy has declined and is generally reserved for patients that fail multiple medical therapies. Splenectomy removes the primary site of platelet clearance and autoantibody production and offers the highest rate of durable response (50% to 70%) compared with other ITP therapies. However, there are no reliable predictors of splenectomy response, and long-term risks of infection and cardiovascular complications must be considered. Because the long-term efficacy of different second-line medical therapies for ITP have not been directly compared, treatment decisions must be made without supportive evidence. Splenectomy continues to be a reasonable treatment option for many patients, including those with an active lifestyle who desire freedom from medication and monitoring, and patients with fulminant ITP that does not respond well to medical therapy. We try to avoid splenectomy within the first 12 months after ITP diagnosis for most patients to allow for spontaneous or therapy-induced remissions, particularly in older patients who have increased surgical morbidity and lower rates of response, and in young children. Treatment decisions must be individualized based on patients' comorbidities, lifestyles, and preferences. Future research should focus on comparing long-term outcomes of patients treated with different second-line therapies and on developing personalized medicine approaches to identify subsets of patients most likely to respond to splenectomy or other therapeutic approaches.

Perspective: interesterified triglycerides, the recent increase in deaths from heart disease, and elevated blood viscosity

The authors hypothesize that consumption of interesterified fats may be the cause of the continuous increase in cardiovascular deaths in the United States which began in 2011. Interesterification is a method of producing solid fats from vegetable oil and began to supplant partial hydrogenation for this purpose upon recognition of the danger of trans fats to cardiovascular health. Long, straight carbon chains, as are present in saturated and trans fatty acids, decrease the fluidity of the erythrocyte cell membrane, which decreases erythrocyte deformability and increases blood viscosity. This decrease in cell membrane fluidity is caused by increased van der Waals interactions, which also solidify dietary fats. Elevated blood viscosity is favored as the pathogenic mechanism by which trans fats increase cardiovascular mortality because changes in lipoprotein levels do not account for all the mortality attributable to their consumption. The rapid changes in cardiovascular mortality noted with the introduction and withdrawal of trans fats from the food supply are reviewed. The evidence implicating elevated blood viscosity in cardiovascular disease is also reviewed. Data regarding the production and consumption of interesterified fats in the US should be released in order to determine if there is an association with the observed increase in cardiovascular deaths.

Risk of venous thromboembolism in patients with splenic injury and splenectomy

The spleen is a crucial organ in humans. However, little is known about the association of venous thromboembolism (VTE) with splenic injury and splenectomy in trauma patients. The aim of this study was to determine the subsequent risk of VTE following splenic injury and splenectomy. A nationwide retrospective cohort study was conducted by analysing data from the National Health Insurance Research Database in Taiwan. We included 6,162 splenic injury patients (3,033 splenectomised and 3,129 nonsplenectomised patients) and 24,648 comparison patients who were selected by frequency match based on sex, age, and the index year during 2000–2006. All patients were followed until the occurrence of VTE, 31 December, 2011, death, or withdrawal from the insurance program. The age of patients with splenic injury was 41.93 ± 16.44 years. The incidence rates of VTE were 11.81, 8.46, and 5.21 per 10,000 person-years in the splenic injury patients with splen -ectomy, splenic injury patients without splenectomy, and comparison patients, respectively. Compared with the comparison cohort, splenic injury patients with splenectomy exhibited a 2.21-fold risk of VTE (95 % confidence interval [CI], 1.43–3.43), whereas those without splenectomy exhibited a 1.71-fold risk of VTE (95 % CI, 1.05–2.80). The overall incidence rate of VTE was 1.97-fold higher in the splenic injury cohort than the comparison cohort (95 % CI, 1.38–2.81). Although splenectomy increased the risk of VTE 1.35-fold compared with no splenectomy, the difference was not statistically significant (95 % CI, 0.74–2.45). These results may alert physicians and patients to the complications of splenic injury and splenectomy.

Persistent changes in circulating white blood cell populations after splenectomy

The effect of splenectomy on the incidence of infections and thromboembolisms has been investigated thoroughly. Nevertheless, the long-term effects of splenectomy on immunological profile and circulating blood counts have not been described before. To study such long-term effects, we analysed several parameters in splenectomised trauma patients and compared the results of this group ("otherwise healthy patients") to patients with a specific underlying disease. We measured platelet count, leukocytes and differential, lymphocyte subsets, serum levels of immunoglobulins, and complement pathways in 113 patients. Indications to perform a splenectomy were trauma (n = 42), Hodgkin lymphoma (n = 24), hereditary spherocytosis (n = 21), and immune thrombocytopenia (n = 26). In trauma patients lymphocytes and lymphocytes subsets were particularly elevated compared to normal population values. Splenectomised patients with Hodgkin lymphoma had significant lower numbers of T lymphocytes than trauma patients. Significant increases in platelets, leukocytes, and monocytes were observed in patients with hereditary spherocytosis. Occurrence of MBL genotype was different in ITP patients than in other splenectomised groups and the normal population. In splenectomised patients (> 4 years), platelet counts and lymphocyte subsets are increased which persist over time. As a result, these blood counts in splenectomised patients differ from reference values in the normal population.

Red blood cells in thrombosis

Red blood cells (RBCs) have historically been considered passive bystanders in thrombosis. However, clinical and epidemiological studies have associated quantitative and qualitative abnormalities in RBCs, including altered hematocrit, sickle cell disease, thalassemia, hemolytic anemias, and malaria, with both arterial and venous thrombosis. A growing body of mechanistic studies suggests that RBCs can promote thrombus formation and enhance thrombus stability. These findings suggest that RBCs may contribute to thrombosis pathophysiology and reveal potential strategies for therapeutically targeting RBCs to reduce thrombosis.

Risk of cardiovascular events and pulmonary hypertension following splenectomy - a Danish population-based cohort study from 1996-2012

Splenectomized patients are at increased risk of cardiovascular events, but it remains unclear whether this is due to lack of the spleen or due to the underlying disease leading to splenectomy. We aimed to assess the risk of myocardial infarction, pulmonary hypertension, and stroke following splenectomy. We identified patients splenectomized in Denmark between 1996 and 2012. We constructed two comparison cohorts: an age- and sex-matched general population cohort and a disease-matched cohort based on the splenectomy-related underlying disease. We computed 5-year cumulative incidences and adjusted hazard ratios of myocardial infarction, pulmonary hypertension, and stroke for the three cohorts. The study included 5,306 splenectomized patients, 53,060 members of the general population, and 11,651 disease-matched patients. During the 5-year follow-up, 1.3% of splenectomized patients had a myocardial infarction versus 1.8% of the population cohort. The adjusted hazard ratio for myocardial infarction in splenectomized patients versus the population cohort was 1.24 (95% confidence interval: 1.01–1.52). The 5-year cumulative incidence of pulmonary hypertension was 0.4% among splenectomized subjects and 0.2% in the population cohort [adjusted hazard ratio 3.25 (95% confidence interval: 1.93–5.45)], while that of stroke was 3.3% among splenectomized patients versus 2.6% in the population cohort [adjusted hazard ratio 2.04 (95% confidence interval: 1.78–2.35)]. When comparing splenectomized subjects with the disease-matched cohort, only stroke risk was elevated, with 5-year risks of 3.0% and 2.3%, respectively [adjusted hazard ratio 1.56 (95% confidence interval: 1.26–1.92)]. In conclusion, splenectomized patients were at increased risk of stroke. Additionally, we found that underlying splenectomy-related diseases explained the increased risk of myocardial infarction and pulmonary hypertension following splenectomy.

Recommendations regarding splenectomy in hereditary hemolytic anemias

Hereditary hemolytic anemias are a group of disorders with a variety of causes, including red cell membrane defects, red blood cell enzyme disorders, congenital dyserythropoietic anemias, thalassemia syndromes and hemoglobinopathies. As damaged red blood cells passing through the red pulp of the spleen are removed by splenic macrophages, splenectomy is one possible therapeutic approach to the management of severely affected patients. However, except for hereditary spherocytosis for which the effectiveness of splenectomy has been well documented, the efficacy of splenectomy in other anemias within this group has yet to be determined and there are concerns regarding short- and long-term infectious and thrombotic complications. In light of the priorities identified by the European Hematology Association Roadmap we generated specific recommendations for each disorder, except thalassemia syndromes for which there are other, recent guidelines. Our recommendations are intended to enable clinicians to achieve better informed decisions on disease management by splenectomy, on the type of splenectomy and the possible consequences. As no randomized clinical trials, case control or cohort studies regarding splenectomy in these disorders were found in the literature, recommendations for each disease were based on expert opinion and were subsequently critically revised and modified by the Splenectomy in Rare Anemias Study Group, which includes hematologists caring for both adults and children.

Venous Thromboembolism in Children with Cancer and Blood Disorders

Venous thromboembolism (VTE) in children is multifactorial and most often related to a combination of inherited and acquired thrombophilias. Children with cancer and blood disorders are often at risk for VTE due to disease-related factors such as inflammation and abnormal blood flow and treatment-related factors such as central venous catheters and surgery. We will review risk factors for VTE in children with leukemia, lymphoma, and solid tumors. We will also review risk factors for VTE in children with blood disorders with specific focus on sickle cell anemia and hemophilia. We will present the available evidence and clinical guidelines for prevention and treatment of VTE in these populations.

Hematological disorders and pulmonary hypertension

Pulmonary hypertension (PH), a serious disorder with a high morbidity and mortality rate, is known to occur in a number of unrelated systemic diseases. Several hematological disorders such as sickle cell disease, thalassemia and myeloproliferative diseases develop PH which worsens the prognosis. Associated oxidant injury and vascular inflammation cause endothelial damage and dysfunction. Pulmonary vascular endothelial damage/dysfunction is an early event in PH resulting in the loss of vascular reactivity, activation of proliferative and antiapoptotic pathways leading to vascular remodeling, elevated pulmonary artery pressure, right ventricular hypertrophy and premature death. Hemolysis observed in hematological disorders leads to free hemoglobin which rapidly scavenges nitric oxide (NO), limiting its bioavailability, and leading to endothelial dysfunction. In addition, hemolysis releases arginase into the circulation which converts L-arginine to ornithine, thus bypassing NO production. Furthermore, treatments for hematological disorders such as immunosuppressive therapy, splenectomy, bone marrow transplantation, and radiation have been shown to contribute to the development of PH. Recent studies have shown deregulated iron homeostasis in patients with cardiopulmonary diseases including pulmonary arterial hypertension (PAH). Several studies have reported low iron levels in patients with idiopathic PAH, and iron deficiency is an important risk factor. This article reviews PH associated with hematological disorders and its mechanism; and iron homeostasis and its relevance to PH.

Giant right ventricular outflow tract thrombus in hereditary spherocytosis: a case report

Background

In hereditary spherocytosis with severe anemia, splenectomy is a recommended treatment. However, the spleen carries an important role both in immune function and coagulation. The increased risk of bacterial infections associated with splenectomy is well known. Recently, hypercoagulation disorders have also been linked to splenectomy through loss of regulation of platelet activity, loss of filtering function and post-splenectomy thrombocytosis.

Case presentation

A 28 year-old smoking women who had previously undergone splenectomy due to hereditary spherocytosis with a moderate thrombocytosis (platelet count 553–635*10⁹/L), presented with recurrent episodes of pulmonary embolisms. Further examination by multimodality cardiac imaging demonstrated a giant chronic thrombus in the right ventricular outflow tract, which eventually had to be surgically removed.

Conclusions

The present case highlights the increased risk of severe thromboembolic complications following therapeutic splenectomy in hereditary spherocytosis, and emphasis the important role of multimodality cardiac imaging in recurrent pulmonary embolism, diagnosing a giant chronic thrombus in the right ventricular outflow tract.

Electronic supplementary material

The online version of this article (doi:10.1186/s12959-016-0083-3) contains supplementary material, which is available to authorized users.

Critical Illness in Patients With Asplenia

The critically ill, asplenic patient presents a variety of management challenges. Historically, the focus of the care of the asplenic population has been the prevention and management of infection, including the often-fatal overwhelming postsplenectomy infection with encapsulated organisms such as Streptococcus pneumoniae. Recently, however, there has been increasing recognition of the spleen's function in areas outside of immunity because the asplenic state has been identified as a risk factor for such vascular complications as thrombosis and pulmonary hypertension resulting from dysregulated inflammation and coagulation. Because of the relatively small size of this population and the relative infrequency with which critical illness occurs in it, there are few controlled trials that can serve as a basis for therapeutic maneuvers; thus, optimal management requires an astute clinician with an understanding of the pathogenetic mechanisms underlying the reported consequences of splenectomy. The purpose of this review is to explore the pathophysiology of the asplenic state-impairment in adaptive immunity, loss of blood filtration, endothelial dysfunction, and dysregulated coagulation-and how it leads to infection, thrombosis, and pulmonary hypertension as well as to discuss the implications of these conditions on the management of the critically ill, splenectomized patient.

Spinal Cord Infarction in a Patient with Hereditary Spherocytosis: A Case Report and Discussion

The etiology of spinal cord infarcts (SCIs), besides being related to aortic perioperative events, in large subset of SCIs, remains cryptogenic. We present a first case of SCI in a patient with hereditary spherocytosis and discuss the potential pathophysiologic considerations for vascular compromise. A 43-year-old woman with a history of hereditary spherocytosis, post splenectomy status, presented with chest, back, and shoulder pain with subsequent myelopathic picture; SCI extending from C4-T2 was confirmed by MRI. Despite aggressive treatment her stroke progressed leading to her demise. Her autopsy confirmed the SCI and revealed some incidental findings, but the cause of SCI remained unidentified. Exclusion of the known etiologies of SCI by extensive negative workup including autopsy evaluation suggested that SCI in our case was related to her history of hereditary spherocytosis. Both venous and arterial adverse vascular events, at a higher rate, have been associated in patients with hereditary spherocytosis who had their spleens removed compared to nonsplenectomized patients. Postsplenectomy increases in the platelet, red blood cell count, leukocyte count, and cholesterol concentrations are postulated to contribute to increased thrombotic risk. Additional prothrombotic factors include continuous platelet activation and adhesion as well as abnormalities of the red blood cell membrane.

Risk factors for venous thromboembolism in adults with hemoglobin SC or Sβ(+) thalassemia genotypes

INTRODUCTION

Venous thromboembolism (VTE) is common in sickle cell disease (SCD); however, the risk factors associated with VTE in patients with sickle variant syndromes are not known. The primary aim of this study was to determine hematologic and clinical risk factors for VTE in adults with hemoglobin SC or Sβ(+) thalassemia genotypes.

MATERIALS AND METHODS

We conducted a retrospective cross-sectional analysis of patients with hemoglobin SC and Sβ(+) thalassemia genotypes followed at the Sickle Cell Center for Adults from 2008 to 2012. Data on baseline hematologic parameters and SCD-specific comorbidities were collected from review of electronic records.

RESULTS

A total of 116 patients, 85 (73%) with hemoglobin SC disease and 31 (27%) with Sβ(+)-thalassemia, were included for analysis. Thirty-two (28%) patients had a verified history of non-catheter related VTE. Mean baseline hemoglobin levels were higher among individuals with a history of VTE compared to those without (11.7g/dL vs. 11.0g/dL, p=0.003). In addition, the prevalence of surgical splenectomy was higher among patients with VTE compared to those without (25.0% vs. 4.8%, p=0.001). On multivariate analysis, elevated baseline hemoglobin (odds ratio [OR] 2.45 (95% confidence interval [CI] 1.42-4.23)) and history of surgical splenectomy (OR 5.76 [CI 1.43-23.22]) were independently associated with VTE risk.

CONCLUSIONS

Higher baseline hemoglobin is a risk factor for non-catheter-related VTE in patients with hemoglobin SC or Sβ(+) thalassemia genotypes. Surgical splenectomy, which is a known risk factor for VTE in other hemoglobinopathies such as β-thalassemia intermedia, is also associated with VTE in sickle variant syndromes. Future studies are needed to validate these findings and to investigate the mechanisms of hypercoagulability observed in patients with hemoglobin SC and Sβ(+) thalassemia.

Increased Risk of Hemorrhagic and Ischemic Strokes in Patients With Splenic Injury and Splenectomy: A Nationwide Cohort Study

The spleen is a crucial organ in humans. Little is known about the association between stroke and splenic injury or splenectomy. The aim of this study was to determine the risk of stroke in patients with splenic injury and splenectomy.A nationwide cohort study was conducted by analyzing the National Health Insurance Research Database in Taiwan. For comparison, control patients were selected and matched with splenic injury patients in a ratio of 4:1 according to age, sex, and the year of hospitalization. We analyzed the risks of stroke using a Cox proportional-hazards regression analysis.A total of 11,273 splenic injury patients, including 5294 splenectomized and 5979 nonsplenectomized patients, and 45,092 control patients were included in this study. The incidence rates of stroke were 8.05, 6.53, and 4.25 per 1000 person-years in splenic injury patients with splenectomy, those without splenectomy, and the control cohort, respectively. Compared with the control cohort, splenic injury patients with splenectomy exhibited a 2.05-fold increased risk of stroke (95% confidence interval [CI] 1.8-2.34), whereas those without splenectomy exhibited a 1.74-fold increased risk (95% CI 1.51-2). Splenectomy entailed an additional 1.21-fold increased risk of stroke compared with nonsplenectomy in patients with splenic injury.This study revealed that splenic injury and splenectomy were significantly associated with an increased risk of hemorrhagic and ischemic strokes. The results of this study may alert physicians and patients to the complications of splenic injury and splenectomy.

Changes in cerebral blood flow in children with sickle cell disease after splenectomy

The study assessed changes in cerebral blood flow and need for chronic blood transfusions in sickle cell disease children after splenectomy. A retrospective chart review of 40 children splenectomized between 1999 and 2014 was performed. The mean time-average maximum velocity before splenectomy was 129 cm/sec; which increased to 157 cm/sec and then decreased to 137 cm/sec, 2 and 5 years postsplenectomy, respectively. There was a persistent and statistically significant elevation in platelet count noted after splenectomy. The mean cerebral blood flow velocity seemed to increase transiently after splenectomy. Close monitoring and screening for stroke risk should be continued postsplenectomy.

Mechanisms linking red blood cell disorders and cardiovascular diseases

The present paper aims to review the main pathophysiological links between red blood cell disorders and cardiovascular diseases, provides a brief description of the latest studies in this area, and considers implications for clinical practice and therapy. Anemia is associated with a special risk in proatherosclerotic conditions and heart disease and became a new therapeutic target. Guidelines must be updated for the management of patients with red blood cell disorders and cardiovascular diseases, and targets for hemoglobin level should be established. Risk scores in several cardiovascular diseases should include red blood cell count and RDW. Complete blood count and hemorheological parameters represent useful, inexpensive, widely available tools for the management and prognosis of patients with coronary heart disease, heart failure, hypertension, arrhythmias, and stroke. Hypoxia and iron accumulation cause the most important cardiovascular effects of sickle cell disease and thalassemia. Patients with congenital chronic hemolytic anemia undergoing splenectomy should be monitored, considering thromboembolic and cardiovascular risk.

New perspectives on the thrombotic complications of haemolysis

Many clinical settings are associated with haemolysis, from rare conditions, such as paroxysmal nocturnal haemoglobinuria, to common interventions, such as mechanical circulatory support and blood transfusion. The toxic effects of circulating free haemoglobin, haem, and iron are becoming increasingly understood and include an increased risk of thrombotic complications. This review summarizes the epidemiological evidence for an association between haemolysis and thrombosis and explores potential underlying mechanisms. New insights into the role haem plays in inflammatory signalling and in generating neutrophil extracellular traps (NETs) may provide useful strategies for managing pathological states associated with severe haemolysis. A better understanding of the toxic effects of haemolysis will result in better therapies to prevent the side effect of thrombosis.

Risk factors for thromboembolism and pulmonary artery hypertension following splenectomy in children with hereditary spherocytosis

BACKGROUND

The aim was to study risk-factors for vascular thrombosis and incidence of pulmonary artery hypertension (PAH) in splenectomized children with hereditary spherocytosis (HS) at a single center.

PROCEDURE

Pre- and post-splenectomy hemoglobin and platelet counts were recorded. Post-splenectomy lipid-profile, fibrinogen, D-dimer, CRP and anti-coagulant-protein levels were compared to established controls. Echo-Doppler was performed for PAH.

RESULTS

Twenty-six children with HS had undergone splenectomy; the mean age at surgery was 7.9 ± 3.7 years. Nineteen of the 26 were prospectively investigated at a median duration of 4.5 years (range: 4 months to 19 years) following splenectomy. Thrombocytosis was observed in 19 (73%), whereas no patient had erythrocytosis at the last follow-up visit. Total cholesterol, LDL-C, HDL-C, and triglyceride levels were not deranged (P ≥ 0.3). Mean CRP levels (males: 2.8 ± 0.5; females: 2.1 ± 0.5 mg/L) were significantly higher than described for normal children (P < 0.001). Six (23%) patients had a positive D-dimer assay. Protein S, anti-thrombin-III and fibrinogen were in range. A single patient had a borderline low protein C activity. Lupus anticoagulant and anti-cardiolipin antibody assays were negative. The mean tricuspid regurgitant jet velocity (TRJV) was 1.8 ± 0.55 meter per second (range: 0-2.4). None had a TRJV ≥2.5 meter per second to suggest PAH.

CONCLUSIONS

There was no evidence of PAH, dyslipidemia, elevation of fibrinogen or a reduction in anti-coagulant proteins, at a median follow-up duration of 4.5 years following splenectomy in children with HS. However, elevated CRP level (42%), persistent thrombocytosis (73%) and elevated D-dimer levels (23%) were observed. These have been recognized as risk factors for cerebrovascular and coronary heart disease.

Benefits and risks of splenectomy

Splenectomy is a powerful therapeutic procedure in a wide variety of medical disorders provided that it is not undertaken lightly and the risks are weighed against the potential benefits in each individual case. Most of this risk seems to be due to the underlying splenectomy indication and not to splenectomy alone. There has been an increased tendency in recent years towards splenic preservation to prevent not only the risk of subsequent overwhelming post-splenectomy infection (OPSI) but the long term risk of cardiovascular complications. As there is no condition that can be cured by splenectomy, this paper reviewed the rationale behind the indications for, and the associated risks.

METHOD

Electronic searches of the medline (PubMed) database, Cochrane library, and science citation index were performed to identify original published studies on splenectomy. Relevant articles were searched from relevant chapters in specialized texts and all included.

Abnormalities of the erythrocyte membrane

Primary abnormalities of the erythrocyte membrane are characterized by clinical, laboratory, and genetic heterogeneity. Among this group, hereditary spherocytosis patients are more likely to experience symptomatic anemia. Treatment of hereditary spherocytosis with splenectomy is curative in most patients. Growing recognition of the long-term risks of splenectomy has led to re-evaluation of the role of splenectomy. Management guidelines acknowledge these considerations and recommend discussion between health care providers, patient, and family. The hereditary elliptocytosis syndromes are the most common primary disorders of erythrocyte membrane proteins. However, most elliptocytosis patients are asymptomatic and do not require therapy.