Delayed pulmonary hypertension following splenectomy for congenital spherocytosis

Echocardiographic Evaluation in Paediatric Sickle Cell Disease Patients: A Pilot Study

Cardiovascular involvement has a great impact on morbidity and mortality in sickle cell disease (SCD). Currently, few studies are available regarding the paediatric setting and, moreover, current guidelines for the echocardiogram screening program in the asymptomatic paediatric population are controversial. We performed a retrospective observational monocentric study on 64 SCD patients (37 male and 27 female, median age 10) at the Bambino Gesù Childrens' Hospital, who had undergone a routine transthoracic echocardiogram. In total, 46 (72%) patients had at least one cardiac abnormality. Left atrial dilatation (LAD) was present in 41 (65%) patients and left ventricular hypertrophy (LVH) was found in 29 (45%) patients. Patients with LAD showed lower median haemoglobin levels (p = 0.009), and a higher absolute reticulocyte count (p = 0.04). LVH was negatively correlated with the median haemoglobin value (p = 0.006) and positively with the reticulocyte count (p = 0.03). Moreover, we found that patients with cardiac anomalies had higher transfusion needs and a lower frequency of pain crises. In our setting, cardiac involvement has a high prevalence in the paediatric cohort and seems to be associated with specific laboratory findings, and with a specific clinical phenotype characterized by complications related to high haemodynamic load.

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.

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.

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.

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.

Post splenectomy related pulmonary hypertension

Splenectomy predisposes patients to a slew of infectious and non-infectious complications including pulmonary vascular disease. Patients are at increased risk for venous thromboembolic events due to various mechanisms that may lead to chronic thromboembolic pulmonary hypertension (CTEPH). The development of CTEPH and pulmonary vasculopathy after splenectomy involves complex pathophysiologic mechanisms, some of which remain unclear. This review attempts to congregate the current evidence behind our understanding about the etio-pathogenesis of pulmonary vascular disease related to splenectomy and highlight the controversies that surround its management.

Malignant systemic hypertension, encephalopathy and bradycardia following splenectomy for hereditary spherocytosis

An 8-year-old girl suffering from hereditary spherocytosis underwent splenectomy for chronic severe anaemia. Surgery was uneventful and the patient had a good early postoperative recovery. On the third postoperative day, however, she developed severe headache with associated abnormal movements of upper limbs and nystagmus. She had a heart rate of 50 bpm and a blood pressure of 180/110 mm Hg. She was managed with triple antihypertensives, antiepileptics and sedatives. She recovered slowly over 2 weeks and is fine at 5 months follow-up.

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.

Pulmonary hypertension associated with chronic hemolytic anemia and other blood disorders

Pulmonary hypertension (PH) has emerged as a major complication of several hematologic disorders, including hemoglobinopathies, red cell membrane disorders, chronic myeloproliferative disorders, and splenectomy. With the exception of sickle cell disease, there are a limited number of studies systematically evaluating the prevalence of PH using the gold standard right heart catheterization in these disorders. The cause of the PH in patients with hematologic disorders is multifactorial, and a thorough diagnostic evaluation is essential. More importantly, there are virtually no high-quality data on the safety and efficacy of PH-targeted therapy in this patient population.

Pulmonary hypertension in patients with hematological disorders following splenectomy

Prevalence of pulmonary arterial hypertension (PAH) was studied by Echocardiography and Doppler in 43 splenectomised patients with various disorders 1-20 years after splenectomy. PAH was detected only in thalassemia major, intermedia, hereditary sphereocytosis and myelofibrosis groups comprising a total of 21 patients. Six patients out of 21 was found to have PAH with mean pulmonary arterial pressure of 46.28 ± 28.17 mmHg. Twenty one controls having similar duration and type of disease also were assessed for PAH in this case control study 3/21 had PAH in this control group. The difference in number of patients showing pulmonary hypertension between case and control was not statistically significant (chi-square test p = 0.29-though the difference in pulmonary arterial pressure between case and control were significantly different (t-test p<0.0029) with control group showing a mean pulmonary arterial pressure of 25 ± 19 mmHg.Platelet count in the splenectomised group was significantly higher (p = 0.0029) than the controls. Pulmonary thromboembolism was equally high in the PAH patients with and without splenectomy. Patients undergoing splenectomy due to trauma, immune thrombocytopenia, sideroblastic anemia, extra hepatic portal hypertension, autoimmune hemolytic anemia did not show PAH after splenectomy even years after the procedure PAH following splenectomy is common after certain disorders and control patients with these diseases have tendency to develop PAH even without splenectomy. Pulmonary thromboembolism may be an important pathophysiological mechanism leading to this condition. Patients having hemolytic anemia and myelofibrosis should have regular evaluation of pulmonary arterial pressure whether he/she has been splenectomised or not. This is particularly important as availability of phosphodiesterase inhibitors like sildenafil allows one to manage these cases.

Vascular complications after splenectomy for hematologic disorders

The most widely recognized long-term risk of splenectomy is overwhelming bacterial infection. More recently, thrombosis has become appreciated as another potential complication of the procedure. Because of these long-term risks, the indications for and timing of splenectomy are debated in the medical community. Accordingly, the adverse effects and benefits of splenectomy for hematologic disorders and other conditions demand further study. This comprehensive review summarizes the existing literature pertaining to vascular complications after splenectomy for hematologic conditions and attempts to define the potential pathophysiologic mechanisms involved. This complex topic encompasses diverse underlying conditions for which splenectomy is performed, diverse thrombotic complications, and multiple pathophysiologic mechanisms.

Pulmonary hypertension in patients with hematological disorders following splenectomy

Prevalence of pulmonary arterial hypertension (PAH) was studied by echocardiography and Doppler in 43 splenectomized patients with various disorders 1-20 years after splenectomy. Pulmonary arterial hypertension was detected only in thalassemia major, intermedia, hereditary sphereocytosis and myelofibrosis groups comprising a total of 21 patients. Six patients out of 21 was found to have PAH with mean pulmonary arterial pressure of 46.28 ± 28.17 mm of Hg. Twenty-one controls having similar duration and type of disease also were assessed for PAH in this case control study 3/21 had pulmonary arterial hypertension in this control group. The difference in number of patients showing pulmonary hypertension between case and control was not statistically significant (Chi square test P=0.29) though the difference in pulmonary arterial pressure between case and control were significantly different (t test P<0.0029) with control group showing a mean pulmonary arterial pressure of 25 ± 19 mm Hg.Platelet count in the splenectomized group was significantly higher (P=0.0029) than the controls. Pulmonary thromboembolism was equally high in the PAH patients with and without splenectomy. Patients undergoing splenectomy due to trauma, immune thrombocytopenia, sideroblastic anemia, extrahepatic portal hypertension, autoimmune hemolytic anemia did not show PAH after splenectomy even years after the procedure PAH following splenectomy is common after certain disorders and control patients in these diseases have tendency to develop PAH even without splenectomy. Pulmonary thromboembolism may be an important pathophysiological mechanism leading to this condition. Patients having hemolytic anemia and myelofibrosis should have regular evaluation of pulmonary arterial pressure whether he/she has been splenectomized or not.This is particularly important as availability of phosphodiesterase inhibitors such as sildenafil allows one to manage these cases.

Hereditary spherocytosis

Hereditary spherocytosis is a common inherited disorder that is characterised by anaemia, jaundice, and splenomegaly. It is reported worldwide and is the most common inherited anaemia in individuals of northern European ancestry. Clinical severity is variable with most patients having a well-compensated haemolytic anaemia. Some individuals are asymptomatic, whereas others have severe haemolytic anaemia requiring erythrocyte transfusion. The primary lesion in hereditary spherocytosis is loss of membrane surface area, leading to reduced deformability due to defects in the membrane proteins ankyrin, band 3, beta spectrin, alpha spectrin, or protein 4.2. Many isolated mutations have been identified in the genes encoding these membrane proteins; common hereditary spherocytosis-associated mutations have not been identified. Abnormal spherocytes are trapped and destroyed in the spleen and this is the main cause of haemolysis in this disorder. Common complications are cholelithiasis, haemolytic episodes, and aplastic crises. Splenectomy is curative but should be undertaken only after careful assessment of the risks and benefits.

Laboratory markers of thrombosis risk in children with hereditary spherocytosis

BACKGROUND

Recent data suggest that adults with hereditary spherocytosis (HS) may be protected from atherothrombosis before splenectomy but have increased risk of thrombosis following splenectomy. In order to aid in making informed decisions regarding splenectomy in children with HS, we conducted a retrospective study of several surrogate laboratory markers of thrombosis risk in children with HS.

METHODS

A retrospective record review was performed on 246 children with HS. Platelet count and hemoglobin concentration were recorded prior to and following splenectomy in each patient. Serum cholesterol levels were collected from the record when available.

RESULTS

Prior to splenectomy, hypocholesterolemia was common. Mean platelet counts in 31 evaluable patients pre- and post-splenectomy were 334 and 608 x 10(9)/L, respectively (P < 0.001). Twenty-nine patients (94%) exhibited persistent thrombocytosis following splenectomy. Hemoglobin values following splenectomy often rose to higher than age and gender-matched norms, with 30% of measurements greater than the 90th percentile and 17% greater than the 97th percentile.

CONCLUSIONS

The findings of hypocholesterolemia before splenectomy and thrombocytosis and mild polycythemia afterwards support the hypothesis that patients with HS might be protected from thrombosis before splenectomy and/or more susceptible afterwards. Prospective studies of additional prothrombotic biomarkers and thrombotic events in HS patients are warranted.

Severity of pulmonary hypertension during vaso-occlusive pain crisis and exercise in patients with sickle cell disease

Pulmonary hypertension is associated with sudden death and is a risk factor for mortality in adult patients with sickle cell disease. The high mortality despite only mild-to-moderate increases in pulmonary vascular resistance remains an unresolved paradox. Accordingly, little is known about the cardiovascular effects of stressors, such as vaso-occlusive pain crisis (VOC) and exercise, which may acutely increase pulmonary pressures and impair right heart function. We therefore evaluated pulmonary artery pressures by echocardiogram in 25 patients with sickle cell disease in steady-state and during VOC, and by right heart catheterisation with exercise in a second cohort of 21 patients to determine whether pulmonary hypertension worsens during acute cardiopulmonary stress. TRV increased during VOC (P < 0.001), and the increased pulmonary pressures during VOC were associated with decreases in haemoglobin levels (P < 0.001), and increases in lactate dehydrogenase (P < 0.001) and plasma haemoglobin levels (P = 0.03). During exercise stress performed during cardiac catheterisation, mean pulmonary artery pressures (P < 0.001) and pulmonary vascular resistance increased (P < 0.001) in all subjects. These data suggest that acute elevations in pulmonary pressures during VOC or exercise may contribute to morbidity and mortality in patients with sickle cell disease.

Deconstructing sickle cell disease: reappraisal of the role of hemolysis in the development of clinical subphenotypes

Hemolysis, long discounted as a critical measure of sickle cell disease severity when compared with sickle vaso-occlusion, may be the proximate cause of some disease complications. New mechanistic information about hemolysis and its effects on nitric oxide (NO) biology and further examination of the subphenotypes of disease requires a reappraisal and deconstruction of the clinical features of sickle cell disease. The biology underlying clinical phenotypes linked to hemolysis may increase our understanding of the pathogenesis of other chronic hemolytic diseases while providing new insights into treating sickle cell disease. The pathophysiological roles of dysregulated NO homeostasis and sickle reticulocyte adherence have linked hemolysis and hemolytic rate to sickle vasculopathy. Nitric oxide binds soluble guanylate cyclase which converts GTP to cGMP, relaxing vascular smooth muscle and causing vasodilatation. When plasma hemoglobin liberated from intravascularly hemolyzed sickle erythrocytes consumes NO, the normal balance of vasoconstriction:vasodilation is skewed toward vasoconstriction. Pulmonary hypertension, priapism, leg ulceration and stroke, all subphenotypes of sickle cell disease, can be linked to the intensity of hemolysis. Hemolysis plays less of a role in the vaso-occlusive-viscosity complications of disease like the acute painful episode, osteonecrosis of bone and the acute chest syndrome. Agents that decrease hemolysis or restore NO bioavailability or responsiveness may have potential to reduce the incidence and severity of the hemolytic subphenotypes of sickle cell disease. Some of these drugs are now being studied in clinical trials.

Lactate dehydrogenase as a biomarker of hemolysis-associated nitric oxide resistance, priapism, leg ulceration, pulmonary hypertension, and death in patients with sickle cell disease

Pulmonary hypertension is prevalent in adult patients with sickle cell disease and is strongly associated with early mortality and markers of hemolysis, in particular, serum lactate dehydrogenase (LDH). Intravascular hemolysis leads to impaired bioavailability of nitric oxide (NO), mediated by NO scavenging by plasma oxyhemoglobin and by arginine degradation by plasma arginase. We hypothesized that serum LDH may represent a convenient biomarker of intravascular hemolysis and NO bioavailability, characterizing a clinical subphenotype of hemolysis-associated vasculopathy. In a cohort of 213 patients with sickle cell disease, we found statistically significant associations of steady-state LDH with low levels of hemoglobin and haptoglobin and high levels of reticulocytes, bilirubin, plasma hemoglobin, aspartate aminotransferase, arginase, and soluble adhesion molecules. LDH isoenzyme fractionation confirmed predominance of LD1 and LD2, the principal isoforms within erythrocytes. In a subgroup, LDH levels closely correlated with plasma cell-free hemoglobin, accelerated NO consumption by plasma, and impaired vasodilatory responses to an NO donor. Remarkably, this simple biomarker was associated with a clinical subphenotype of pulmonary hypertension, leg ulceration, priapism, and risk of death in patients with sickle cell disease. We propose that LDH elevation identifies patients with a syndrome of hemolysis-associated NO resistance, endothelial dysfunction, and end-organ vasculopathy.

Chronic sickle cell lung disease: new insights into the diagnosis, pathogenesis and treatment of pulmonary hypertension

Pulmonary hypertension is a common complication of sickle cell disease (SCD). In spite of the mild elevations in pulmonary artery pressures in these patients, the associated morbidity and mortality is high. In fact, in adult patients with SCD, pulmonary hypertension is emerging as the major independent risk factor for death. The aetiology of pulmonary hypertension is probably multifactorial, including haemolysis, impaired nitric oxide bioavailability, chronic hypoxaemia, thromboembolism, parenchymal and vascular injury because of sequestration of sickle erythrocytes, chronic liver disease and asplenia. Interestingly, pulmonary hypertension is emerging as a common, and probably, invariant sequella of lifelong haemolytic anaemia in other hereditary and acquired haemolytic diseases, such as thalassaemia, stomatocytosis and spherocytosis. There are currently limited specific data on the effects of any treatment modality for pulmonary hypertension in patients with SCD. It is likely that maximization of SCD therapy, in all patients, and treatment with selective pulmonary vasodilators and antiproliferative agents, in patients with severe disease, would be beneficial. A large trial evaluating the effects of therapy for pulmonary hypertension in the SCD population is clearly indicated.

Red cell membrane disorders

Disorders of the erythrocyte membrane, including hereditary spherocytosis, hereditary elliptocytosis, hereditary pyropoikilocytosis, and hereditary stomatocytosis, comprise an important group of inherited hemolytic anemias. These syndromes are characterized by marked clinical and laboratory heterogeneity. Recent molecular studies have revealed that there is also significant genetic heterogeneity in these disorders. This is particularly true for the spherocytosis syndromes where each kindred has a private mutation in one of the spherocytosis genes. Treatment with splenectomy is curative in most patients. Splenectomy via a laparoscopic approach has become the surgical method of choice. Growing recognition and understanding of the long-term risks and complications of splenectomy, including cardiovascular disease, thrombotic disorders, and pulmonary hypertension, and the emergence of penicillin-resistant pneumococci, a concern for infection in overwhelming postsplenectomy infection, have led to reevaluation of the role of splenectomy. Recent management guidelines acknowledge these important considerations when entertaining splenectomy and recommend detailed discussion between health care providers, patient, and family.