Vascular complications after splenectomy for hematologic disorders

β-Thalassemia intermedia: a comprehensive overview and novel approaches

β-Thalassemia intermedia is a clinical condition of intermediate gravity between β-thalassemia minor, the asymptomatic carrier, and β-thalassemia major, the transfusion-dependent severe anemia. It is characterized by a significant clinical polymorphism, which is attributable to its genetic heterogeneity. Ineffective erythropoiesis, chronic anemia, and iron overload contribute to the clinical complications of thalassemia intermedia through stepwise pathophysiological mechanisms. These complications, including splenomegaly, extramedullary erythropoiesis, iron accumulation, leg ulcers, thrombophilia, and bone abnormalities can be managed via fetal hemoglobin induction, occasional transfusions, chelation, and in some cases, stem cell transplantation. Given its clinical diversity, thalassemia intermedia patients require tailored approaches to therapy. Here we present an overview and novel approaches to the genetic basis, pathophysiological mechanisms, clinical complications, and optimal management of thalassemia intermedia.

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.

Tissue factor-bearing microparticles and inflammation: a potential mechanism for the development of venous thromboembolism in cancer

Cancer is associated with an increased risk of venous thromboembolism (VTE); the exact mechanisms for the induction of VTE remain to be fully elucidated, but it is widely acknowledged that tissue factor (TF)-bearing microparticles (TF-MPs) may play a significant role. However, TF-MPs have yet to be accepted as a genuine biomarker for cancer-associated VTE, as the presence of elevated TF-MP levels is not always accompanied by thrombosis; interestingly, in certain cases, particularly in pancreatic cancer, VTE seems to be more likely in the context of acute inflammation. Although several potential mechanisms for the development of VTE in cancer have been postulated, this review explores the homeostatic disruption of TF-MPs, as the main reservoir of bloodborne TF, in the context of cancer and inflammation, and considers the abrogated responses of the activated endothelium and mononuclear phagocyte system in mediating this disruption.

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.

A long-term follow-up study of subtotal splenectomy in children with hereditary spherocytosis

BACKGROUND

Hereditary spherocytosis (HS) is a heterogeneous hemolytic anemia treated with splenectomy in patients suffering from severe or moderate disease. Total splenectomy, however, renders patients vulnerable to overwhelming postsplenectomy infection despite preventive measures. Although subtotal splenectomy has been advocated as an alternative to total splenectomy, long-term follow-up data are scarce. We investigated how often hematologic recurrences requiring secondary total splenectomy occurred.

PROCEDURE

With a follow-up of at least 5 years, we analyzed the data of 12 patients, aged 11 years maximum (median 6.5 years), who had undergone intended subtotal splenectomy, and 9 patients (median age 11.9 years), who had undergone total splenectomy. We compared their hematologic results and searched for factors associated with secondary spleen surgery.

RESULTS

Hemolysis was reduced after subtotal splenectomy and absent after total splenectomy. Subtotal splenectomy was not successful in three children because no functional splenic remnant remained after 6 months (one conversion at surgery; one necrosis of splenic remnant; one early secondary splenectomy). Four children required secondary splenectomy after a median of 5 years for hematologic recurrence. In the remaining five patients, a functional splenic remnant was present for at least 5.5 years. The median time to secondary total splenectomy after intended subtotal splenectomy was 5.2 years. In all patients requiring secondary total splenectomy, increased reticulocyte levels within 2 years indicated hematologic recurrence.

CONCLUSIONS

Subtotal splenectomy can be an alternative for total splenectomy in young patients with HS. It allows for hematologic improvement and may preserve splenic immune function for as many as 5 years.

Non syndromic childhood onset congenital sideroblastic anemia: A report of 13 patients identified with an ALAS2 or SLC25A38 mutation

The most frequent germline mutations responsible for non syndromic congenital sideroblastic anemia are identified in ALAS2 and SLC25A38 genes. Iron overload is a key issue and optimal chelation therapy should be used to limit its adverse effects on the development of children. Our multicentre retrospective descriptive study compared the strategies for diagnosis and management of congenital sideroblastic anemia during the follow-up of six patients with an ALAS2 mutation and seven patients with an SLC25A38 mutation. We described in depth the clinical, biological and radiological phenotype of these patients at diagnosis and during follow-up and highlighted our results with a review of available evidence and data on the management strategies for congenital sideroblastic anemia. This report confirms the considerable variability in manifestations among patients with ALAS2 or SLC25A38 mutations and draws attention to differences in the assessment and the monitoring of iron overload and its complications. The use of an international registry would certainly help defining recommendations for the management of these rare disorders to improve patient outcome.

Fatal pulmonary embolism following splenectomy in a patient with Evan's syndrome: case report and review of the literature

Background

Evans syndrome (ES) is a rare disease characterized by simultaneous or sequential development of autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP) with or without immune neutropenia. Splenectomy is one of the treatment options for disease refractory to medical therapy. Venous thromboembolism (VTE) following splenectomy for hematological diseases has an incidence of 10%.

Case presentation

Here we describe a case report of a young patient hospitalized with severe hemolytic anemia with Hgb 4.8 g/dl. He developed thrombocytopenia with platelet nadir of 52,000/mm³, thus formally diagnosed with ES. He failed standard medical therapy. He underwent splenectomy and had a fatal outcome. Autopsy confirmed the cause of death as pulmonary embolism (PE).

Conclusions

This case report and review of the literature highlight important aspects of the association between VTE, splenectomy, and hemolytic syndromes including the presence of thrombocytopenia. The burden of the disease is reviewed as well as various pathophysiologic mechanisms contributing to thromboembolic events in these patients and current perioperative prophylactic anticoagulation strategies. Despite an advancing body of literature increasing awareness of VTE following splenectomy, morbidity and mortality remains high. Identifying high risk individuals for thromboembolic complications from splenectomy remains a challenge. There are no consensus guidelines for proper perioperative and post-operative anti-coagulation. We encourage future research to determine which factors might be playing a role in increasing the risk for VTE in real time with hope of forming a consensus to guide management.

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.

Achieving a satisfactory clinical and biochemical response in antiphospholipid syndrome and severe thrombocytopenia with rituximab: two case reports

In AP syndrome (APS) with severe thrombocytopenia, rituximab represents a unique drug which can balance the effect of bleeding and thrombosis. By reducing the production of autoantibodies, rituximab can simultaneously raise the platelets and reduce the chance of thrombosis by suppressing APL antibodies. Rituximab can supersede splenectomy as second‐line therapy in similar patients.

Safety and efficacy of romiplostim in splenectomized and nonsplenectomized patients with primary immune thrombocytopenia

Primary immune thrombocytopenia is an autoimmune disorder characterized by increased platelet destruction and insufficient platelet production without another identified underlying disorder. Splenectomy may alter responsiveness to treatment and/or increase the risk of thrombosis, infection, and pulmonary hypertension. The analysis herein evaluated the safety and efficacy of the thrombopoietin receptor agonist romiplostim in splenectomized and nonsplenectomized adults with primary immune thrombocytopenia. Data were pooled across 13 completed clinical studies in adults with immune thrombocytopenia from 2002-2014. Adverse event rates were adjusted for time of exposure. Results were considered different when 95% confidence intervals were non-overlapping. Safety was analyzed for 1111 patients (395 splenectomized; 716 nonsplenectomized) who received romiplostim or control (placebo or standard of care). At baseline, splenectomized patients had a longer median duration of immune thrombocytopenia and a lower median platelet count, as well as a higher proportion with >3 prior immune thrombocytopenia treatments versus nonsplenectomized patients. In each treatment group, splenectomized patients used rescue medications more often than nonsplenectomized patients. Platelet response rates (≥50×10⁹/L) for romiplostim were 82% (310/376) for splenectomized and 91% (592/648) for nonsplenectomized patients (P<0.001 by Cochran-Mantel-Haenszel test). Platelet responses were stable over time in both subgroups. Exposure-adjusted adverse event rates were higher for control versus romiplostim for both splenectomized (1857 versus 1226 per 100 patient-years) and nonsplenectomized patients (1052 versus 852 per 100 patient-years). In conclusion, responses to romiplostim were seen in both splenectomized and nonsplenectomized patients, and romiplostim was not associated with an increase in the risk of adverse events in splenectomized patients. clinicaltrials.gov Identifier: 00111475(A)(B), 00117143, 00305435, 01143038, 00102323, 00102336, 00415532, 00603642, 00508820, 00907478, 00116688, and 00440037.

Feasibility and safety of emergency laparoscopic partial splenectomy: A retrospective analysis

The increased awareness of asplenia-related life-threatening complications has led to the development of parenchyma sparing splenic resections in past few years. The aim of this study is to retrospectively analyze the feasibility and safety of laparoscopic partial splenectomy (LPS) in selected emergency patients.From January 2013 to December 2015, there were 46 emergency patients, diagnosed with splenic rupture, admitted in our department. Selection criteria for LPS: (1) Preoperative CT scan revealed single pole rupture without spleen pedicle injury; (2) BP>90/60 mm Hg and heart rates <120 bpm; (3) No sigh of multiple organ injury. Eventually, LPS was performed in 21 patients (Group LPS), while laparoscopic splenectomy (LS) was performed in 20 patients (Group LS).The main cause of splenic rupture was traffic accident, followed by blunt injury and high falling injury. Abdominal CT scan showed the mean longitudinal diameter of spleen of group LPS was 14.2 ± 1.8 cm (range 12-17 cm), while the size of remnant spleen was 5.5 ± 1.2 cm. Between 2 groups, operation time (LPS: 122.6 ± 17.2 min vs LS: 110.5 ± 18.7 minutes, P = .117), and intraoperative blood loss (LPS: 174 ± 22 mL vs LS: 169 ± 29 mL, P = .331) were similar. There were 2 patients suffered subsequent unstable vital sign altering during mobilization when performing LPS. Conversion to LS (2/21, 9.52%) was decided and successfully completed. Although there was no patient suffered postoperative OPSI or thrombocytosis events in both groups after 6-month follow-up, the mean platelets and leukocyte count were significantly lower in group LPS. Splenic regrowth was evaluated in 20 patients of group LPS. And the mean regrowth of splenic volume reached 19% (10%-26%).Due to its minimal invasive effect and functional splenic tissue preservation, LPS may be a safe and feasible approach for emergency patients. And prospective trials with clear inclusion criteria are needed to proof the benefit of LPS.

Hypercoagulability after distal pancreatectomy: Just meaningless alterations?

BACKGROUND

Perioperative and short-term postoperative parameters are similar comparing spleen-preserving distal pancreatectomy (SPDP) and distal pancreatectomy with splenectomy (DPS). But there are no sound data evaluating the long term risk of postoperative thromboses and infectious complications after splenectomy. The present study evaluated whether the coagulation status differs in patients after SPDP and DPS, and whether that matters clinically.

METHODS

A total of 41 patients after DP (SPDP = 20; DPS = 21) were followed up, focusing on alterations of patient coagulation and immune status. To assess kinetics of the coagulation process, qualitative tests (multiple platelet function analyzer, rotational thrombelastography) were used in addition to global coagulation tests.

RESULTS

Coagulation tests revealed a significant enhanced tendency for blood-platelet aggregation and coagulation activation in patients after DPS compared to patients after SPDP. No septic or thromboembolic events were observed in any patient.

CONCLUSION

Hypercoagulability in splenectomized patients persists over years. Thus, a correlation of this finding with thromboembolic events and mortality years after splenectomy should to be performed in a large cohort.

Congenital Hemolytic Anemia

Red blood cell (RBC) destruction can be secondary to intrinsic disorders of the RBC or to extrinsic causes. In the congenital hemolytic anemias, intrinsic RBC enzyme, RBC membrane, and hemoglobin disorders result in hemolysis. The typical clinical presentation is a patient with pallor, anemia, jaundice, and often splenomegaly. The laboratory features include anemia, hyperbilirubinemia, and reticulocytosis. For some congenital hemolytic anemias, splenectomy is curative. However, in other diseases, avoidance of drugs and toxins is the best therapy. Supportive care with transfusions are also mainstays of therapy. Chronic hemolysis often results in the formation of gallstones, and cholecystectomy is often indicated.

Homozygous α-thalassemia: Challenges surrounding early identification, treatment, and cure

The prognosis for homozygous α-thalassemia is changing. Prenatal diagnosis and intrauterine transfusions (IUT) reduce maternofetal morbidity and mortality; hematopoietic stem cell transplant (HSCT) is curative. Empiric evidence to support IUT and HSCT to treat homozygous α-thalassemia is lacking. The first case of curative HSCT for homozygous α-thalassemia was reported in 1997. Nearly 20 years later, five additional reports are published. We review the literature and report an institutional experience with three homozygous α-thalassemia patients. The first died shortly after birth. The second underwent HSCT after years of chronic transfusion therapy. The third benefited from IUT and HSCT. These cases exemplify the varied outcomes associated with this condition.

Knowledge insufficient: the management of haemoglobin SC disease

Although haemoglobin SC (HbSC) accounts for 30% of sickle cell disease (SCD) in the United States and United Kingdom, evidence-based guidelines for genotype specific management are lacking. The unique pathology of HbSC disease is complex, characterized by erythrocyte dehydration, intracellular sickling and increased blood viscosity. The evaluation and treatment of patients with HbSC is largely inferred from studies of SCD consisting mostly of haemoglobin SS (HbSS) patients. These studies are underpowered to allow definitive conclusions about HbSC. We review the pathophysiology of HbSC disease, including known and potential differences between HbSS and HbSC, and highlight knowledge gaps in HbSC disease management. Clinical and translational research is needed to develop targeted treatments and to validate management recommendations for efficacy, safety and impact on quality of life for people with HbSC.

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.

Case Reports of Idiopathic Thrombocytopenia Unresponsive to First-Line Therapies Treated With Traditional Herbal Medicines Based on Syndrome Differentiation

The objective of our study is to present two cases showing the effects of traditional Korean herbal medicines based on traditional Korean medicine (TKM) for the treatment of immune thrombocytopenic purpura (ITP). One patient showed no response to treatment with steroids and an immunosuppressive agent. Moreover, liver toxicity and side effects of steroids were evident. However, after he ceased conventional treatment and started to take an herbal medicine, his liver function normalized and the steroid side effects resolved. Ultimately, he achieved complete remission. Another patient with ITP had sustained remission after steroid therapy in childhood, but extensive uterine bleeding and thrombocytopenia recurred when she was 16 years old. She was managed with steroids again for 2 years, but severe side effects occurred, and eventually she ceased taking steroids. She refused a splenectomy, and was then treated with a herbal medicine for 7 months, ultimately leading to sustained remission again. Many patients with resistance to first-line treatments tend to be reluctant to undergo a splenectomy, considered a standard second-line treatment. In conclusion, herbal medicines, based on TKM, may offer alternative treatments for persistent or chronic ITP that is resistant to existing first-line treatments.

Coinhibition of the deubiquitinating enzymes, USP14 and UCHL5, with VLX1570 is lethal to ibrutinib- or bortezomib-resistant Waldenstrom macroglobulinemia tumor cells

The survival of Waldenstrom macroglobulinemia (WM) tumor cells hinges on aberrant B-cell receptor (BCR) and MYD88 signaling. WM cells upregulate the proteasome function to sustain the BCR-driven growth while maintaining homeostasis. Clinically, two treatment strategies are used to disrupt these complementary yet mutually exclusive WM survival pathways via ibrutinib (targets BTK/MYD88 node) and bortezomib (targets 20 S proteasome). Despite the success of both agents, WM patients eventually become refractory to treatment, highlighting the adaptive plasticity of WM cells and underscoring the need for development of new therapeutics. Here we provide a comprehensive preclinical report on the anti-WM activity of VLX1570, a novel small-molecule inhibitor of the deubiquitinating enzymes (DUBs), ubiquitin-specific protease 14 (USP14) and ubiquitin carboxyl-terminal hydrolase isozyme L5 (UCHL5). Both DUBs reside in the 19 S proteasome cap and their inhibition by VLX1570 results in rapid and tumor-specific apoptosis in bortezomib- or ibrutinib-resistant WM cells. Notably, treatment of WM cells with VLX1570 downregulated BCR-associated elements BTK, MYD88, NFATC, NF-κB and CXCR4, the latter whose dysregulated function is linked to ibrutinib resistance. VLX1570 administered to WM-xenografted mice resulted in decreased tumor burden and prolonged survival (P=0.0008) compared with vehicle-treated mice. Overall, our report demonstrates significant value in targeting USP14/UCHL5 with VLX1570 in drug-resistant WM and carries a high potential for clinical translation.

Long-term complications of splenectomy in adult immune thrombocytopenia

The recent large decrease in splenectomy use for chronic immune thrombocytopenia (ITP) is partly due to still-unsolved questions about long-term safety. We performed the first single-center exposed/unexposed cohort study evaluating the long-term incidence of splenectomy complications in patients with primary ITP. Overall, 83 patients who underwent splenectomy more than 10 years ago (exposed) were matched with 83 nonsplenectomized patients (unexposed) on the date of ITP diagnosis ±5 years, age and gender. After a median follow-up of 192 months (range 0.5-528), 43 patients (52%) achieved overall response after splenectomy. Splenectomized patients experienced more venous thromboembolism (VTE) than controls (n = 13 vs n = 2, P = 0.005). On multivariate analysis, splenectomy was an independent risk factor of VTE (hazard ratio = 4.006, P = 0.032 [95% confidence interval: 1.13-14.21]). Splenectomized patients presented more severe infections on long-term follow-up: all required hospitalization, and 5/26 (19%) infections led to severe sepsis or septic shock and to death for 3 cases (none in controls). However, the incidence of malignancy was similar in both groups, as was cardiovascular risk, which appeared to be related more to ITP than splenectomy. Finally, splenectomy did not significantly decrease overall survival. Despite the risk of thrombosis and severe sepsis, splenectomy remains an effective and curative treatment for ITP.

Biomechanics of red blood cells in human spleen and consequences for physiology and disease

Red blood cells (RBCs) can be cleared from circulation when alterations in their size, shape, and deformability are detected. This function is modulated by the spleen-specific structure of the interendothelial slit (IES). Here, we present a unique physiological framework for development of prognostic markers in RBC diseases by quantifying biophysical limits for RBCs to pass through the IES, using computational simulations based on dissipative particle dynamics. The results show that the spleen selects RBCs for continued circulation based on their geometry, consistent with prior in vivo observations. A companion analysis provides critical bounds relating surface area and volume for healthy RBCs beyond which the RBCs fail the "physical fitness test" to pass through the IES, supporting independent experiments. Our results suggest that the spleen plays an important role in determining distributions of size and shape of healthy RBCs. Because mechanical retention of infected RBC impacts malaria pathogenesis, we studied key biophysical parameters for RBCs infected with Plasmodium falciparum as they cross the IES. In agreement with experimental results, surface area loss of an infected RBC is found to be a more important determinant of splenic retention than its membrane stiffness. The simulations provide insights into the effects of pressure gradient across the IES on RBC retention. By providing quantitative biophysical limits for RBCs to pass through the IES, the narrowest circulatory bottleneck in the spleen, our results offer a broad approach for developing quantitative markers for diseases such as hereditary spherocytosis, thalassemia, and malaria.

Biomechanics of red blood cells in human spleen and consequences for physiology and disease

Red blood cells (RBCs) can be cleared from circulation when alterations in their size, shape, and deformability are detected. This function is modulated by the spleen-specific structure of the interendothelial slit (IES). Here, we present a unique physiological framework for development of prognostic markers in RBC diseases by quantifying biophysical limits for RBCs to pass through the IES, using computational simulations based on dissipative particle dynamics. The results show that the spleen selects RBCs for continued circulation based on their geometry, consistent with prior in vivo observations. A companion analysis provides critical bounds relating surface area and volume for healthy RBCs beyond which the RBCs fail the "physical fitness test" to pass through the IES, supporting independent experiments. Our results suggest that the spleen plays an important role in determining distributions of size and shape of healthy RBCs. Because mechanical retention of infected RBC impacts malaria pathogenesis, we studied key biophysical parameters for RBCs infected with Plasmodium falciparum as they cross the IES. In agreement with experimental results, surface area loss of an infected RBC is found to be a more important determinant of splenic retention than its membrane stiffness. The simulations provide insights into the effects of pressure gradient across the IES on RBC retention. By providing quantitative biophysical limits for RBCs to pass through the IES, the narrowest circulatory bottleneck in the spleen, our results offer a broad approach for developing quantitative markers for diseases such as hereditary spherocytosis, thalassemia, and malaria.

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.

Influence of experimental Anaplasma marginale infection and splenectomy on NTPDase and 5'nucleotidase activities in platelets of cattle

The objective of this paper was to evaluate NTPDase and 5'-nucleotidase activities in platelets of bovine with and without spleen and infected by Anaplasma marginale. Our results demonstrate that infection along with splenectomy is able of inducing a profile of cellular protection, which showed an increase in the degradation of the nucleotides ATP and ADP by NTPDase, in addition to AMP by 5'nucleotidase to form the nucleoside adenosine in platelets, i.e., the enzymatic activities of platelets were increased in splenectomized animals when compared to non-splenectomized group. It notes that adenosine is a molecule with anti-inflammatory function. But this profile is related to a deficiency in immune signaling triggered by nucleotide ATP, which may be related to the increase in bacteremia and disability in combating the parasite in splenectomized host.

Role of romiplostim in splenectomized and nonsplenectomized patients with immune thrombocytopenia

Romiplostim is a thrombopoietin receptor agonist (TPO-RA) used for the treatment of adult primary immune thrombocytopenia (ITP). ITP is an autoimmune condition characterized by low platelet counts due to increased destruction and reduced platelet production. First-line interventions include corticosteroids, anti-D, and intravenous immunoglobulins, while second-line therapies comprise splenectomy, rituximab, cyclosporine A, and TPO-RAs. The recognition that compromised platelet production is a critical part of the pathogenesis of ITP prompted the development of therapeutic strategies based on the stimulation of the TPO receptor. TPO-RAs enhance megakaryocyte proliferation, increase platelet production, and lead to a reduction in bleeding episodes in ITP patients. This review will summarize current data on the TPO-RA romiplostim, with a particular focus on its relation to splenectomy.

Is ITP a thrombophilic disorder?

Immune thrombocytopenia (ITP) represents the epitome of acquired bleeding diseases for the hematologist. Stemming from the interest for the safety of thrombopoietin-receptor agonists (TPO-ra) romiplostim and eltrombopag, recent data have investigated if thrombotic risk is also increased in this disorder. In patients not treated with TPO-ra, a slightly higher risk of venous thrombosis (VTE) is consistently found in ITP, but not to a rate demanding special attention in the generality of cases. No significant increase of arterial thrombosis (AT) is apparent. However, age, splenectomy, and personal risk factors may put some ITP patient to a particularly higher risk of venous and arterial thrombosis (three to four times higher than the average subject). Patients exposed to TPO-ra present indirect evidence of a much higher risk of both AT and VTE. Unfortunately, no matched control population is available and the prospective and registrative nature of these studies may have emphasized the incidence of thrombosis, which was recorded as adverse event. The clinician should be able to individualize the best treatment for the patient, taking also into account the thrombotic risk, limiting active treatment of ITP to those patients really at risk of bleeding.

Comparative efficacy and cost effectiveness of splenectomy and thrombopoietin prior to peginterferon and ribavirin therapy with compensatory cirrhosis associated with hepatitis C and thrombocytopenia

The aim of the present study was to evaluate and compare the treatment efficacy and cost of two therapies, splenectomy and thrombopoietin, in order to optimize the treatment plans for patients with HCV-associated cirrhosis. A prospective randomized controlled trial was conducted on 69 patients with a platelet count <60,000/mm³ that were enrolled between 2009 and 2013, including 38 cases as the research group and 31 cases as the observed group. The study included two stages: A 4-week initial treatment and a 48-week antiviral treatment, during which a number of parameters were evaluated, including platelet count, liver stiffness measure, albumin, total bilirubin, alanine aminotranferase and treatment cost-effectiveness. Of the 38 patients, 21 underwent a splenectomy and their platelet counts increased to 60,000/mm³ after the 4-week initial treatment. The patients then started a 48-week P-R antiviral treatment, and 18 cases completed the treatment. In addition, 17/38 patients received thrombopoietin as a drug therapy. The platelet counts in 15 cases increased to >60,000/mm³ and the patients received antiviral treatment, among which 9 cases completed the second treatment stage. The expense of the splenectomy group treatment was higher compared with that received by the thrombopoietin group. The results of the present study indicated that splenectomy was more effective at increasing platelet count. More splenectomy patients completed the full course of antiviral treatment and presented a sustained virologic response, compared with the thrombopoietin group. Therefore, splenectomy may be more expensive compared with thrombopoietin; however, the improved efficacy suggests that on balance it is the preferable treatment option.

Persistent thrombocytopaenia in a young man with splenomegaly, rebound thrombocytosis after splenectomy and subsequent pulmonary embolism: splenic littoral cell angioma and associated events

Littoral cell angioma (LCA) is a rare endothelial cell neoplasm in the spleen. Although many cases of LCA are asymptomatic, some present with signs and symptoms related to splenomegaly, whereas others manifest with haematological abnormalities, including anaemia and/or thrombocytopaenia (ie, hypersplenism). We report a case of LCA presenting with chronic thrombocytopaenia, probably due to splenic sequestration of platelets or phagocytosis of platelets by neoplastic cells. Following therapeutic splenectomy, the patient suffered from a marked rebound thrombocytosis and subsequently developed pulmonary embolisms. He was treated with anticoagulant therapy combined with antiplatelet therapy, and his symptoms were quickly resolved. This case emphasises an exclusion of primary splenic disorders in patients with chronic thrombocytopaenia, especially in those with splenomegaly and the contemplation of thromboembolism prophylaxis postsplenectomy.

Splenectomy is associated with a higher risk for venous thromboembolism: A prospective cohort study

BACKGROUND

Thrombocytosis following splenectomy is a common occurrence. Whether this thrombocytosis leads to a higher risk for venous thromboembolism (VTE) remains unclear. This investigation aimed to determine if splenectomy increases the risk for VTE.

METHODS

This was a prospective study conducted in the SICU between 1/2011 and 11/2013 investigating the VTE risk in patients undergoing a splenectomy compared with those undergoing any other abdominal procedure.

RESULTS

In total 2503 patients were admitted to the SICU: 37 (2%) after a splenectomy and 638 (26%) after any other abdominal surgery. Splenectomy patients had a higher incidence of VTE compared to patients undergoing any other abdominal procedure (29.7% vs. 12.1%, p < 0.01). After adjustment, splenectomy was associated with a higher adjusted risk for VTE compared to the no-splenectomy group (AOR [95% CI]: 2.6 [1.2, 5.9], p = 0.02). Reactive thrombocytosis did not predict the development of VTE.

CONCLUSION

Splenectomy increases the risk for VTE, however reactive thrombocytosis is not associated with this higher incidence. Further investigations are required to characterize the pathophysiologic mechanisms of VTE development following splenectomy.

Role of splenic monocytes in atherosclerosis

PURPOSE OF REVIEW

This review relates recent findings that highlight the role of the spleen as an active donor of monocytes during inflammation, with a special focus on atherosclerosis.

RECENT FINDINGS

The contribution of hypercholesterolemia and monocytes/macrophages to atherosclerotic lesion formation is undisputable. The origin of plaque macrophages is, however, still a subject of debate as to whether they derive from local amplification of (resident) macrophages or from continuous recruitment and differentiation of monocytes. Recently, the spleen has emerged as an important reservoir of monocytes that contributes to lesion growth. The regulation of monocyte mobilization from the splenic compartment has, therefore, raised a keen interest in understanding the cellular and molecular mechanisms involved in this process.

SUMMARY

Impaired regulation of cholesterol metabolism increases the proliferation of hematopoietic stem and progenitor cells in both the bone marrow and the spleen. Recent findings identified the implication of angiotensin II, red pulp macrophages and B-lymphocytes as partners of monocyte expansion in, and mobilization from the spleen. Future studies will help in understanding the mechanisms of monocyte mobilization and its precise roles in atherosclerosis, and whether modulation of the splenic components may become a promising future direction in the prevention and treatment of cardiovascular diseases.

Thrombocytosis following splenectomy and aortic valve replacement for idiopathic thrombocytopaenic purpura with bicuspid aortic valve

Idiopathic thrombocytopaenic purpura (ITP) patients are at high risk for complications during and after cardiac surgeries involving cardiopulmonary bypass. The main clinical problem of primary ITP is an increased risk of bleeding although bleeding may not always be present. More recently, thrombosis has become appreciated as another potential complication of the procedure. We report a 22-year-old female patient with ITP with bicuspid aortic valve and splenomegaly, who underwent uncomplicated aortic valve replacement and splenectomy simultaneously. She was readmitted with chest pain due to coronary thrombosis following splenectomy which made the management difficult. We describe our experience in managing this patient who presented with thrombotic complication rather than bleeding in post-operative period and the challenges met in maintaining appropriate anticoagulation for aortic valve replacement as well as thrombosis, post-splenectomy

[Robot-assisted and laparoscopic partial splenectomy for nonparasitic cysts]

21 patients with nonparasitic spleen cysts were operated. Robot-assisted (RA) interventions were applied in 10 cases, laparoscopic--in 11 patients. Men surgery duration was 124 minutes in case of RA-technique and 120 minutes if laparoscopy was used. Blood loss was significantly lower in the group of RA resection (p=0.035). There were no conversions of access in the group of RA-operations while in group of laparoscopy conversion has been required in 1 case. We did not observe complications in case of RA-surgeries. Laparoscopic method was associated with 2 complications (left-sided hydrothorax and fluid accumulation in resection area). Postoperative hospital-stay did not differ in both groups and was 7.1 and 6.4 room-nights in case of RA-interventions and laparoscopy respectively. There were no deaths. Indications for robot-assisted partial splenectomy for nonparasitic cysts include location of mass in upper pole or hilus of spleen, its diameter more than 8 cm, body mass index more than 30 and splenomegaly. Lower pole resection and splenectomy are more advisable using laparoscopic method.

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.

Radiation-induced dose-dependent changes of the spleen following postoperative chemoradiotherapy for gastric cancer

BACKGROUND AND PURPOSE

Abdominal (chemo-)radiotherapy is associated with dose-limiting toxicity of various normal structures. The purpose of this retrospective study was to investigate radiation-induced changes of the spleen and their clinical consequences.

PATIENTS AND METHODS

In gastric cancer patients treated with postoperative chemoradiotherapy, the spleen size and its functions were assessed at follow-up by spleen volume on CT-scan, serum leucocytes/thrombocytes, and the occurrence of infectious events consisting of pneumonia and fatal sepsis. To evaluate the effect of radiation dose, mixed effects and Cox regression models were used.

RESULTS

Forty-six out of 90 consecutive patients treated from 2006 to 2011 were evaluable. All patients received 45 Gy in 25 fractions with concurrent capecitabine (n=8), and capecitabine/cisplatin (n=38). Median Dmean to the spleen was 40 Gy (range 32-46). Mean relative spleen volume reduced to 37% (95% CI 32-42%) at 4-year follow-up, which was most strongly associated to the V44 (p<0.001). Median follow-up time was 67 (95% CI 57-78) months. Eleven patients had 13 pneumonias and 3 fatal sepsis. No association with dosimetric parameters was observed.

CONCLUSIONS

In postoperative chemoradiotherapy for gastric cancer, the spleen received a high radiation dose. This resulted in a progressive, radiation dose-dependent reduction of spleen volume. Pneumonia and fatal sepsis occurred frequently, possibly as a result of functional hyposplenia.

Venous thromboembolism related to warm autoimmune hemolytic anemia: a case-control study

BACKGROUND

The risk of venous thromboembolism (VTE) during warm autoimmune hemolytic anemia (wAIHA) is apparent in several published series. Unlike proximate disorders (autoimmune thrombocytopenia, non-immune hemolytic diseases) little is known about the presentation and risk factors for VTE in this setting.

OBJECTIVE

To determine the frequency, presentation and risk factors for VTE associated with wAIHA.

METHODS

We performed a single center retrospective study of adult patients (>18years) followed for wAIHA between 2009 and 2013. VTE risk factors were systematically assessed. The characteristics of patients with or without VTE were compared. VTE presentation and precipitating factors were analyzed. The Padua VTE risk score was calculated in each case.

RESULTS

Forty patients were included. wAIHA was idiopathic in 24 patients (60%). Twelve patients (30%) had Evans syndrome. Mean lowest hemoglobin level was 6.6g/dl [3.7-11.5]. Eight patients (20%) presented VTE after the appearance of wAIHA, at a mean age of 52.5years. All patients had pulmonary embolus, associated with a deep venous thrombosis in 4 cases. At the time of VTE 7/8 patients had frank hemolysis (median hemoglobin level: 7g/dL) and 6/8 were outpatients with a low Padua VTE risk score. The frequency of usual VTE risk factor was similar in cases and controls. By contrast, lowest hemoglobin level was significantly lower in patients that experienced VTE (5.3 vs 7.2g/dL, p=0.016). During the first episode of wAIHA, patients with concurrent VTE had a more pronounced anemia (5.3 vs 7.4g/dL, p=0.026). At the time of VTE, anemia was more severe when no other precipitating factor was present (6 vs 8.9g.dL, p=0.04).

CONCLUSION

In our cohort, 20% of patients with wAIHA presented VTE. The vast majority of VTE occurred during severe hemolytic flares and were not attributable to usual VTE risk factors. VTE prophylaxis is advisable in any patient admitted for wAIHA, irrespective of Padua VTE risk score. Prophylaxis also seems reasonable for outpatients with marked hemolysis.

Proximal Versus Distal Splenic Artery Embolisation for Blunt Splenic Trauma: What is the Impact on Splenic Immune Function?

PURPOSE

To compare the impact of proximal or distal splenic artery embolisation versus that of splenectomy on splenic immune function as measured by IgM memory B cell levels.

MATERIALS AND METHODS

Patients with splenic trauma who were treated by splenic artery embolisation (SAE) were enrolled. After 6 months splenic volume was assessed by CT, and IgM memory B cells in peripheral blood were measured and compared to a local normal reference population and to a post-splenectomy population.

RESULTS

Of the 71 patients who underwent embolisation, 38 underwent proximal embolisation, 11 underwent distal embolisation, 22 patients were excluded, 1 had both proximal and distal embolisation, 5 did not survive and 16 did not return for evaluation. There was a significant difference between splenectomy and proximal or distal embolisation and a trend towards greater preservation of IgM memory B cell number in those with distal embolisation-a difference that could not be attributed to differences in age, grade of injury or residual splenic volume.

CONCLUSION

IgM memory B cell levels are significantly higher in those treated with SAE compared to splenectomy. Our data provide evidence that splenic embolisation should reduce immunological complications of spleen trauma and suggest that distal embolisation may maintain better function.