NT-pro brain natriuretic peptide levels and the risk of death in the cooperative study of sickle cell disease

Pulmonary Hypertension in Sickle Cell Disease: Novel Findings of Gene Polymorphisms Related to Pathophysiology

Pulmonary hypertension (PH) is a progressive and potentially fatal complication of sickle cell disease (SCD), affecting 6-10% of adult SCD patients. Various mechanisms and theories have been evaluated to explain the pathophysiology of this disease. However, questions remain, particularly regarding the clinical heterogeneity of the disease in terms of symptoms, complications, and survival. Beyond the classical mechanisms that have been thoroughly investigated and include hemolysis, nitric oxide availability, endothelial disorders, thrombosis, and left heart failure, attention is currently focused on the potential role of genes involved in such processes. Potential candidate genes are investigated through next-generation sequencing, with the transforming growth factor-beta (TGF-β) pathway being the initial target. This field of research may also provide novel targets for pharmacologic agents in the future, as is already the case with idiopathic PH. The collection and processing of data and samples from multiple centers can yield reliable results that will allow a better understanding of SCD-related PH as a part of the disease's clinical spectrum. This review attempts to capture the most recent findings of studies on gene polymorphisms that have been associated with PH in SCD patients.

Determinants of ventricular arrhythmias in sickle cell anemia: toward better prevention of sudden cardiac death

Sudden death is 1 of the leading causes of death in adults with sickle cell anemia (SCA) but its etiology remains mostly unknown. Ventricular arrhythmia (VA) carries an increased risk of sudden death; however, its prevalence and determinants in SCA are poorly studied. This study aimed to identify the prevalence and predictors of VA in patients with SCA. From 2019 to 2022, 100 patients with SCA were referred to the physiology department to specifically analyze cardiac function and prospectively included in the DREPACOEUR registry. They underwent a 24-hour electrocardiogram monitoring (24h-Holter), transthoracic echocardiography, and laboratory tests on the same day. The primary end point was the occurrence of VA, defined as sustained or nonsustained ventricular tachycardia (VT), >500 premature ventricular contractions (PVCs) on 24h-Holter, or a recent history of VT ablation. The mean patient age was 46 ± 13 years, and 48% of the patients were male. Overall, VA was observed in 22 (22%) patients. Male sex (81% vs 34%; P = .02), impaired global longitudinal strain (GLS): -16% ± 1.9% vs -18.3% ± 2.7%; P = .02), and decreased platelet count (226 ± 96 giga per liter [G/L] vs 316 ± 130 G/L) were independently associated with VA. GLS correlated with PVC load every 24 hours (r = 0.39; P < .001) and a cutoff of -17.5% could predict VA with a sensitivity of 82% and a specificity of 63%. VAs are common in patients with SCA, especially in men. This pilot study uncovered GLS as a valuable parameter for improving rhythmic risk stratification.

Sickle Cell Disease and the Heart.. [DOI: 10.21203/rs.3.rs-3040535/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Purpose The objective of this study was to explore the relationship between cardiac structure, cardiac index (CI), and diastolic function parameters, and laboratory values in patients with Sickle Cell Disease (SCD), and to characterize the distinct SCD cardiomyopathy phenotype Methods We conducted a retrospective review of 202 adult patients with SCD (mean age 41.02 ± 13.36) at our hospital who underwent outpatient echocardiographic screening from 2019–2022. Results Our study identified cardiac hypertrophy, chamber dilatation with preserved ejection fraction, elevated TRV, increased cardiac output, and diastolic dysfunction as defining echocardiographic features in SCD. There was a negative correlation between CI and lateral e’ (R = -0.182, P = 0.012), and a positive correlation between CI and E/e’ (R = 0.274, P = 0.0001). Conclusions Our study identified a unique cardiomyopathy in patients with SCD characterized by cardiac hypertrophy with preserved systolic function, abnormal mitral inflow patterns, and elevated cardiac output. These features are indicative of restrictive physiology, as evidenced by left atrial enlargement and diastolic dysfunction, superimposed on hyperdynamic physiology. Further research is needed to elucidate the pathophysiological mechanisms underlying these observations and determine their prognostic significance in vulnerable populations with an elevated burden of cardiovascular disease, including the risk of sudden cardiac death.

Effect of a Physical Exercise Program on the Inflammatory Response, Cardiac Functions, Functional Capacity, and Quality of Life in Patients with Sickle Cell Disease

INTRODUCTION

The beneficial effects of physical exercise on functional capacity and inflammatory response are well-known in cardiovascular diseases; however, studies on sickle cell disease (SCD) are limited. It was hypothesized that physical exercise may exert a favorable effect on the inflammatory response of SCD patients, contributing to an improved quality of life. This study aimed to evaluate the effect of a regular physical exercise program on the anti-inflammatory responses in SCD patients.

METHODS

A non-randomized clinical trial was conducted in adult SCD patients. The patients were divided into two groups: 1-Exercise Group, which received a physical exercise program three times a week for 8 weeks, and; 2-Control Group, with routine physical activities. All patients underwent the following procedures initially and after eight weeks of protocol: clinical evaluation, physical evaluation, laboratory evaluation, quality of life evaluation, and echocardiographic evaluation.

STATISTICAL ANALYSIS

Comparisons between groups were made using Student's t-test, Mann-Whitney test, chi-square test, or Fisher's exact test. Spearman's correlation coefficient was calculated. The significance level was set at p < 0.05.

RESULTS

There was no significant difference in inflammatory response between the Control and Exercise Groups. The Exercise Group showed an improvement in peak VO₂ values (p < 0.001), an increase in the distance walked (p < 0.001), an improvement in the limitation domain due to the physical aspects of the 36-Item Short Form Health Survey (SF-36) quality of life questionnaire (p = 0.022), and an increase in physical activity related to leisure (p < 0.001) and walking (p = 0.024) in the International Physical Activity Questionnaire (IPAQ). There was a negative correlation between IL-6 values and distance walked on the treadmill (correlation coefficient -0.444, p = 0.020) and the estimated peak VO₂ values (correlation coefficient -0.480; p = 0.013) in SCD patients in both groups.

CONCLUSIONS

The aerobic exercise program did not change the inflammatory response profile of SCD patients, nor did it show unfavorable effects on the parameters evaluated, and patients with lower functional capacity were those with the highest levels of IL-6.

[Lung manifestations of sickle-cell disease]

Sickle-cell disease is an autosomal recessive genetic disorder of hemoglobin that causes systemic damage. Hypoxia is the main actor of sickle-cell disease. It initiates acutely the pathogenic cascade leading to tissue damages that in turn induce chronic hypoxia. Lung lesions represent the major risk of morbidity and mortality. Management of sickle-cell disease requires a tight collaboration between hematologists, intensivists and chest physicians. Recurrent episodes of thrombosis and hemolysis characterize the disease. New therapeutic protocols, associating hydroxyurea, transfusion program and stem cell transplantation in severe cases allow a prolonged survival until the fifth decade. However, recurrent pain, crisis, frequent hospital admissions due to infection, anemia or acute chest syndrome and chronic complications leading to organ deficiencies degrade the patients' quality of life. In low-income countries where the majority of sickle-cell patients are living, the disease is still associated with a high mortality in childhood. This paper focuses on acute chest syndrome and chronic lung manifestations.

Pulmonary hypertension screening in children with sickle cell disease

BACKGROUND

Screening for pulmonary hypertension (PHT) is recommended in children with sickle cell disease (SCD). However, best approaches are poorly described. We examined the utility of PHT symptoms, echocardiogram (ECHO), N-terminal-pro hormone brain natriuretic peptide (NT-proBNP), and BNP to screen for PHT in the SCD pediatric population.

METHODS

Children (8-18 years old) with SCD-HbSS and HbSthal° were prospectively included and underwent PHT screening. The screening consisted of a comprehensive PHT symptoms evaluation, ECHO measurement, and NT-proBNP and BNP levels.

RESULTS

A total of 73 patients were included (mean age 12 ± 5.7 years; >80% on hydroxyurea), of which 37% had a symptom consistent with PHT, including exertional dyspnea (26.5%), fatigue (17.6%), palpitation (14.7%), and chest pain (10.3%). ECHO was obtained in 53 (72.6%) patients, with only ECHO of 48 patients included in the final analysis. Elevated ECHO peak tricuspid regurgitant jet velocity (TRV) >2.5 m/s or indirect findings to suggest PHT were seen in only two of 48 (4.2%). No significant differences were seen between those with and without PHT symptoms when compared for NT-proBNP, BNP, hemoglobin, pulmonary function testing, fractional exhaled nitric oxide, asthma, oxygen saturation, and sleep apnea.

CONCLUSION

PHT symptoms are not consistent with ECHO, NT-proBNP nor BNP findings in children with SCD. PHT prevalence based on TRV was low in children on hydroxyurea, therefore screening may not be warranted for this group.

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.

The Cardiopulmonary Complications of Sickle Cell Disease

Sickle cell disease (SCD) is a genetic hemoglobinopathy associated with extensive morbidity and early mortality. While there have been recent improvements in available disease-modifying therapies for SCD, cardiopulmonary complications remain a major risk factor for death in this population. We provide an overview of current knowledge regarding several of the major acute and chronic cardiopulmonary complications in SCD, including: acute chest syndrome, airway disease, lung function abnormalities, nocturnal hypoxemia and sleep disordered breathing, pulmonary vascular disease, and sickle cell cardiomyopathy.

Treatment dilemmas: strategies for priapism, chronic leg ulcer disease, and pulmonary hypertension in sickle cell disease

Sickle cell disease is a disorder characterized by chronic hemolytic anemia and multiorgan disease complications. Although vaso-occlusive episodes, acute chest syndrome, and neurovascular disease frequently result in complication and have well-documented guidelines for management, the management of chronic hemolytic and vascular-related complications, such as priapism, leg ulcers, and pulmonary hypertension, is not as well recognized despite their increasing reported prevalence and association with morbidity and mortality. This chapter therefore reviews the current updates on diagnosis and management of priapism, leg ulcers, and pulmonary hypertension.

Multiple inducers of endothelial NOS (eNOS) dysfunction in sickle cell disease

A characteristic aspect of the robust, systemic inflammatory state in sickle cell disease is dysfunction of endothelial nitric oxide synthase (eNOS). We identify 10 aberrant endothelial cell inputs, present in the specific sickle context, that are known to have the ability to cause eNOS dysfunction. These are: endothelial arginase depletion, asymmetric dimethylarginine, complement activation, endothelial glycocalyx degradation, free fatty acids, inflammatory mediators, microparticles, oxidized low density lipoproteins, reactive oxygen species, and Toll‐like receptor 4 signaling ligands. The effect of true eNOS dysfunction on clinical testing using flow‐mediated dilation can be simulated by two known examples of endothelial dysfunction mimicry (hemoglobin consumption of NO; and oxidation of smooth muscle cell soluble guanylate cyclase). This lends ambiguity to interpretation of such clinical testing. The presence of these multiple perturbing factors argues that a therapeutic approach targeting only a single injurious endothelial input (or either example of mimicry) would not be sufficiently efficacious. This would seem to argue for identifying therapeutics that directly protect eNOS function or application of multiple therapeutic approaches.

The different facets of sickle cell disease-related pulmonary hypertension

PURPOSE OF REVIEW

Sickle cell disease (SCD), one of the most common genetic diseases in the world, is characterized by repeated episodes of hemolysis and vaso-occlusion. Hemolytic anemia is a risk factor for the development of pulmonary hypertension, and currently SCD-related pulmonary hypertension is classified as World Health Organization group 5 pulmonary hypertension. Patients with SCD-related pulmonary hypertension have unique hemodynamics, multiple comorbidities, and distinct phenotypes that may contribute to the development of pulmonary hypertension.

RECENT FINDINGS

SCD-related pulmonary hypertension is defined as a mean pulmonary artery pressure >20 mmHg, a pulmonary artery occlusion pressure ≤15 mmHg and relatively low pulmonary vascular resistance (>2 Wood units) rather than the traditional definition of ≥3 Wood units, an important distinction due to a baseline high-cardiac output state in the setting of chronic anemia and low vascular resistance. Diastolic dysfunction is frequently identified in this patient population and right heart catheterization is essential to determine if combined pre- and postcapillary pulmonary hypertension is present. Thromboembolism is common among patients with SCD, and screening for chronic thromboembolic pulmonary hypertension is essential. Data regarding advanced therapies are limited. Primary treatment options include targeting correction of their primary hemoglobinopathy as well as aggressive management of underlying comorbid conditions.

SUMMARY

SCD-related pulmonary hypertension is common among patients with SCD and is associated with increased mortality. A high index of suspicion is warranted during evaluation to identify all potential factors that may be contributing to disease.

A phenotypic risk score for predicting mortality in sickle cell disease

Risk assessment for patients with sickle cell disease (SCD) remains challenging as it depends on an individual physician's experience and ability to integrate a variety of test results. We aimed to provide a new risk score that combines clinical, laboratory, and imaging data. In a prospective cohort of 600 adult patients with SCD, we assessed the relationship of 70 baseline covariates to all-cause mortality. Random survival forest and regularised Cox regression machine learning (ML) methods were used to select top predictors. Multivariable models and a risk score were developed and internally validated. Over a median follow-up of 4·3 years, 131 deaths were recorded. Multivariable models were developed using nine independent predictors of mortality: tricuspid regurgitant velocity, estimated right atrial pressure, mitral E velocity, left ventricular septal thickness, body mass index, blood urea nitrogen, alkaline phosphatase, heart rate and age. Our prognostic risk score had superior performance with a bias-corrected C-statistic of 0·763. Our model stratified patients into four groups with significantly different 4-year mortality rates (3%, 11%, 35% and 75% respectively). Using readily available variables from patients with SCD, we applied ML techniques to develop and validate a mortality risk scoring method that reflects the summation of cardiopulmonary, renal and liver end-organ damage. Trial Registration: ClinicalTrials.gov Identifier: NCT#00011648.

NT-proBNP levels and cardiopulmonary function in children with sickle cell disease

Patients with sickle cell disease (SCD) are living longer and subsequently more apt to develop cardiopulmonary dysfunction. N-terminal pro-brain natriuretic peptide (NT-proBNP) levels have been used in adults with SCD to assess for pulmonary hypertension and mortality. While the incidence of PH is low in pediatrics, it is reasonable to presume that NT-proBNP levels can be used to assess risk for the development of cardiopulmonary morbidity. We hypothesized that NT-proBNP levels would be increased in patients with SCD compared to age-adjusted healthy children; additionally, these levels would be associated with labs indicative of hemolysis and would demonstrate evidence of obstructive lung disease and cardiac dysfunction. We retrospectively evaluated patients with SCD, 8-18 years old, at a large, tertiary care children's hospital. NT-proBNP levels were assessed in correlation with hemolytic lab work, spirometry, and echocardiographic data. The age group 8-14 years old, 75% of our cohort's population, had a median NT-proBNP of 70 pg/ml, greater than their age-adjusted counterparts (52 pg/ml). NT-proBNP levels were associated with an increased degree of hemolysis when compared with hemoglobin (Hb) (r = -0.43, p < .0001), reticulocyte count (r = .25, p = .01) and lactate dehydrogenase levels (r = .47, p < .0001). An inverse trend was found between NT-proBNP and spirometric data. Finally, a positive correlation was found between NT-proBNP and diastolic left ventricular size (r = .28, p = .047]. The correlations found suggest that NT-proBNP may be used prospectively to identify patients with SCD at increased risk for the development of cardiopulmonary dysfunction.

Tricuspid regurgitation velocity and other biomarkers of mortality in children, adolescents and young adults with sickle cell disease in the United States: The PUSH study

In the US, mortality in sickle cell disease (SCD) increases after age 18-20 years. Biomarkers of mortality risk can identify patients who need intensive follow-up and early or novel interventions. We prospectively enrolled 510 SCD patients aged 3-20 years into an observational study in 2006-2010 and followed 497 patients for a median of 88 months (range 1-105). We hypothesized that elevated pulmonary artery systolic pressure as reflected in tricuspid regurgitation velocity (TRV) would be associated with mortality. Estimated survival to 18 years was 99% and to 25 years, 94%. Causes of death were known in seven of 10 patients: stroke in four (hemorrhagic two, infarctive one, unspecified one), multiorgan failure one, parvovirus B19 infection one, sudden death one. Baseline TRV ≥2.7 m/second (>2 SD above the mean in age-matched and gender-matched non-SCD controls) was observed in 20.0% of patients who died vs 4.6% of those who survived (P = .012 by the log rank test for equality of survival). The baseline variable most strongly associated with an elevated TRV was a high hemolytic rate. Additional biomarkers associated with mortality were ferritin ≥2000 μg/L (observed in 60% of patients who died vs 7.8% of survivors, P < .001), forced expiratory volume in 1 minute to forced vital capacity ratio (FEV1/FVC) <0.80 (71.4% of patients who died vs 18.8% of survivors, P < .001), and neutrophil count ≥10x10⁹ /L (30.0% of patients who died vs 7.9% of survivors, P = .018). In SCD children, adolescents and young adults, steady-state elevations of TRV, ferritin and neutrophils and a low FEV1/FVC ratio may be biomarkers associated with increased risk of death.

Allogeneic Hematopoietic Stem Cell Transplantation for Adults with Sickle Cell Disease

Sickle cell disease (SCD) is an inherited red blood cell disorder that leads to substantial morbidity and early mortality. Acute and chronic SCD-related complications increase with older age, and therapies are urgently needed to treat adults. Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative therapy, but has been used less frequently in adults compared to children. This is, in part, due to (1) greater chronic organ damage, limiting tolerability to myeloablative conditioning regimens, (2) a higher rate of HSCT-related complications in adults versus children with SCD, and (3) limited coverage by public and private health insurance. Newer approaches using nonmyeloablative and reduced-intensity conditioning HSCT regimens have demonstrated better safety and tolerability, with high rates of stable engraftment in SCD adults. This review will focus on the impacts of HSCT, using more contemporary approaches to SCD-related complications in adults.

Sickle cell disease: Clinical presentation and management of a global health challenge

Sickle cell disease is an autosomal recessive, multisystem disorder, characterised by chronic haemolytic anaemia, painful episodes of vaso-occlusion, progressive organ failure and a reduced life expectancy. Sickle cell disease is the most common monogenetic disease, with millions affected worldwide. In well-resourced countries, comprehensive care programs have increased life expectancy of sickle cell disease patients, with almost all infants surviving into adulthood. Therapeutic options for sickle cell disease patients are however, still scarce. Predictors of sickle cell disease severity and a better understanding of pathophysiology and (epi)genetic modifiers are warranted and could lead to more precise management and treatment. This review provides an extensive summary of the pathophysiology and management of sickle cell disease and encompasses the characteristics, complications and current and future treatment options of the disease.

Vascular complications of sickle cell disease

Sickle cell disease (SCD) is a monogenetic disorder caused by a mutation in the β-globin gene HBB leading to polymerization of red blood cells causing damage to cell membranes, increasing its rigidity and intravascular hemolysis. Multiple lines of evidence suggest that SCD can be viewed as pan-vasculopathy associated with multiple mechanisms but driven by hemoglobin S polymerization. Here we review the pathophysiology, clinical manifestations and management strategies for cerebrovascular disease, pulmonary hypertension and renal disease associated with SCD. These "vascular phenotypes" reflect the systemic nature of the complications of SCD and are a major threat to the well-being of patients with the disorder.

Intravascular hemolysis and the pathophysiology of sickle cell disease

Hemolysis is a fundamental feature of sickle cell anemia that contributes to its pathophysiology and phenotypic variability. Decompartmentalized hemoglobin, arginase 1, asymmetric dimethylarginine, and adenine nucleotides are all products of hemolysis that promote vasomotor dysfunction, proliferative vasculopathy, and a multitude of clinical complications of pulmonary and systemic vasculopathy, including pulmonary hypertension, leg ulcers, priapism, chronic kidney disease, and large-artery ischemic stroke. Nitric oxide (NO) is inactivated by cell-free hemoglobin in a dioxygenation reaction that also oxidizes hemoglobin to methemoglobin, a non-oxygen-binding form of hemoglobin that readily loses heme. Circulating hemoglobin and heme represent erythrocytic danger-associated molecular pattern (eDAMP) molecules, which activate the innate immune system and endothelium to an inflammatory, proadhesive state that promotes sickle vaso-occlusion and acute lung injury in murine models of sickle cell disease. Intravascular hemolysis can impair NO bioavailability and cause oxidative stress, altering redox balance and amplifying physiological processes that govern blood flow, hemostasis, inflammation, and angiogenesis. These pathological responses promote regional vasoconstriction and subsequent blood vessel remodeling. Thus, intravascular hemolysis represents an intrinsic mechanism for human vascular disease that manifests clinical complications in sickle cell disease and other chronic hereditary or acquired hemolytic anemias.

Elevated tricuspid regurgitant jet velocity, reduced forced expiratory volume in 1 second, and mortality in adults with sickle cell disease

Cardiopulmonary disease is the leading cause of mortality in adults with sickle cell disease (SCD). Elevated tricuspid regurgitant jet velocity (TRJV) and reduced forced expiratory volume in 1 second (FEV₁ ) %predicted are associated with early mortality in SCD; however their relationship and combined effect on survival is unknown. We investigated the relationship between TRJV and FEV₁ %predicted, and their combined effect on mortality, in a retrospective cohort of 189 adults with SCD who underwent both pulmonary function testing and echocardiography. Nineteen (9.9%) of 189 patients died over a median follow-up of 1.4 years; cardiopulmonary disease was the major cause of death in 52.6%. FEV₁ %predicted was negatively associated with TRJV (Spearman rho, -0.34, P < 0.001). Individuals with FEV₁ %predicted ≤70% were more likely to have an elevated TRJV ≥2.5 m/second, compared to those with FEV₁ %predicted >70% [45.8% versus 17.1%; odds ratio (OR) 4.1 (95% Confidence interval ([CI] 2.1-8.0); P = 0.001]. In a multivariable cox regression model, the combination of TRJV ≥2.5 m/second and FEV₁ %predicted ≤70% predicted earlier mortality [hazard ratio (HR) 4.97 (95% CI 1.30-18.91; P = 0.019)] after adjusting for age, sex, and nephropathy. Both FEV₁ %predicted ≤70% and TRJV ≥2.5 m/second were independently associated with nephropathy [OR 4.48 (95% CI 1.51-13.31); P = 0.004] and [OR 3.27 (95% CI 1.19-9.00); P = 0.017], respectively. In conclusion, pulmonary and cardiac impairment are associated with, and contribute to mortality in SCD. Therapies aimed at improving reduced FEV₁ %predicted and elevated TRJV could improve survival in patients with SCD. Am. J. Hematol. 92:125-130, 2017. © 2016 Wiley Periodicals, Inc.

Risk factors for mortality in adult patients with sickle cell disease: a meta-analysis of studies in North America and Europe

Although recent studies show an improved survival of children with sickle cell disease in the US and Europe, for adult patients mortality remains high. This study was conducted to evaluate the factors associated with mortality in adult patients following the approval of hydroxyurea. We first evaluated the association between selected variables and mortality at an academic center (University of North Carolina). Data sources were then searched for publications from 1998 to June 2016, with meta-analysis of eligible studies conducted in North America and Europe to evaluate the associations of selected variables with mortality in adult patients. Nine studies, combined with the UNC cohort (total n=3257 patients) met the eligibility criteria. Mortality was significantly associated with age (per 10-year increase in age) [7 studies, 2306 participants; hazard ratio (HR): 1.28; 95% confidence interval (CI): 1.10-1.50], tricuspid regurgitant jet velocity 2.5 m/s or more (5 studies, 1577 participants; HR: 3.03; 95%CI: 2.0-4.60), reticulocyte count (3 studies, 1050 participants; HR: 1.05; 95%CI: 1.01-1.10), log(N-terminal-pro-brain natriuretic peptide) (3 studies, 800 participants; HR: 1.68; 95%CI: 1.48-1.90), and fetal hemoglobin (7 studies, 2477 participants; HR: 0.97; 95%CI: 0.94-1.0). This study identifies variables associated with mortality in adult patients with sickle cell disease in the hydroxyurea era.

Heart failure in haemoglobinopathies: pathophysiology, clinical phenotypes, and management

Hereditary haemoglobinopathies, mainly beta-thalassemia and sickle cell disease, constitute the most common monogenic disorders in humans, and although once geographically confined, they are currently globally distributed. They are demanding clinical entities that require multidisciplinary medical management. Despite their genotypic and phenotypic heterogeneity, the haemoglobinopathies share several similarities in pathophysiology, clinical manifestations, therapeutic requirements, and complications, among which heart failure (HF) represents a leading cause of mortality and morbidity. However, haemoglobinopathies have generally been addressed in a rather fragmentary manner. A unifying approach focusing on the underlying similarities of HF attributes in the two main entities might contribute to their better understanding, characterization, and management. In the present review, we attempt such an approach to the pathophysiology, clinical phenotypes, and management of HF in haemoglobinopathies.

Review: Hemodynamic Characteristics and Outcomes of Sickle Cell Disease Associated Pulmonary Hypertension

Pulmonary hypertension (PH) is a leading cause of morbidity and early mortality in adults with sickle cell disease (SCD). However, the prevalence, hemodynamic profile and prognosis of SCD-PH remain controversial and need frequent updates. Pulmonary hypertension determined by right heart catheterization (RHC) occurs in 6% to 10% of adults with SCD. Hemodynamically, SCD-PH may be pre-capillary or post-capillary in nature. The exact etiology is unknown and often multifactorial; hence a thorough diagnostic evaluation following established PH guidelines is essential to determine disease prevalence, etiology and outcomes. Data on the efficacy and safety of pulmonary arterial hypertension (PAH) therapy are limited in SCD; clinical trials in these patients are urgently needed. This review provides an overview of RHC-determined hemodynamic characteristics, current management modality and outcomes; we also highlight recent advances and unmet research needs in SCD-PH.

Cardiovascular complications and risk of death in sickle-cell disease

In sickle-cell disease, a point mutation in the β-globin chain causes haemoglobin to polymerise within erythrocytes during deoxygenation, altering red blood cell rheology and causing haemolysis. Improvements in health infrastructure, preventive care, and clinical treatments have reduced the morbidity and mortality of sickle-cell disease in developed countries. However, as these patients live longer, the chronic effects of sustained haemolytic anaemia and episodic vaso-occlusive events drive the development of end-organ complications. Cardiopulmonary organ dysfunction and chronic kidney injury have a large effect on morbidity and premature mortality, and typically accelerate in the second decade of life. These processes culminate in the development of pulmonary hypertension, left ventricular diastolic heart disease, dysrhythmia, and sudden death. In this Series paper, we review the mechanisms, clinical features, and epidemiology of major cardiovascular complications in patients with sickle-cell disease and discuss how screening and intervention could reduce their incidence.

Amino-terminal pro-brain natriuretic peptide in children with latent rheumatic heart disease

Background:

Rheumatic heart disease (RHD) is a global cause of early heart failure. Early RHD is characterized by valvar regurgitation, leading to ventricular distention and possible elaboration of amino-terminal pro-brain natriuretic peptide (NT-proBNP). We investigated the ability of NT-proBNP to distinguish cases of latent RHD detected by echocardiographic screening from the controls.

Materials and Methods:

Ugandan children (N = 44, 36% males, mean age: 12 ± 2 years) with latent RHD (cases) and siblings (controls) by echocardiography were enrolled. Cases and controls were matched for age and sex, and they had normal hemoglobin (mean: 12.8 mg/dL). Children with congenital heart disease, pregnancy, left ventricular dilation or ejection fraction (EF) below 55%, or other acute or known chronic health conditions were excluded. RHD cases were defined by the World Heart Federation (WHF) 2012 consensus guideline criteria as definite. Controls had no echocardiography (echo) evidence for RHD. At the time of echo, venous blood samples were drawn and stored as serum. NT-proBNP levels were measured using sandwich immunoassay. Paired t-tests were used to compare NT-proBNP concentrations including sex-specific analyses.

Results:

The mean NT-proBNP concentration in the cases was 105.74 ± 67.21 pg/mL while in the controls, it was 86.63 ± 55.77 pg/mL. The cases did not differ from the controls (P = 0.3). In sex-specific analyses, male cases differed significantly from the controls (158.78 ± 68.82 versus 76 ± 42.43, P = 0.008). Female cases did not differ from the controls (75.44 ± 45.03 versus 92.30 ± 62.35 respectively, P = 0.4).

Conclusion:

Serum NT-proBNP did not distinguish between latent RHD cases and the controls. Sex and within-family exposures may confound this result. More investigation into biomarker-based RHD detection is warranted.

Lactate dehydrogenase in sickle cell disease

Lactate dehydrogenase (LDH) activity is elevated in many pathological states. Interest in LDH activity in sickle cell disease (SCD) has developed out of an increased comprehension of the pathophysiological process and the clinical course of the disease. Elevated LDH activity in SCD comes from various mechanisms, especially intravascular hemolysis, as well as ischemia-reperfusion damage and tissular necrosis. Intravascular hemolysis is associated with vasoconstriction, platelet activation, endothelial damage, and vascular complications. LDH has been used as a diagnostic and prognostic factor of acute and chronic complications. In this review we have evaluated the literature where LDH activity was examined during steady-state or acute conditions in SCD.

Chronic Pulmonary Complications of Sickle Cell Disease

Sickle cell disease (SCD), the most common genetic hemolytic anemia worldwide, affects 250,000 births annually. In the United States, SCD affects approximately 100,000 individuals, most of African descent. Hemoglobin S (HbS) results from a glutamate-to-valine mutation of the sixth codon of the β-hemoglobin allele; the homozygous genotype (HbSS) is associated with the most prevalent and severe form of the disease. Other SCD genotypes include HbSC, composed of one HbS allele and one HbC (glutamate-to-lysine mutation) allele; and HbS-β-thalassemia(0) or HbS-β-thalassemia(+), composed of one HbS allele and one β-thalassemia allele with absent or reduced β-chain production, respectively. Despite advances in care, median survival remains in the fifth decade, due in large part to chronic complications of the disease. Chronic pulmonary complications in SCD are major contributors to this early mortality. Although our understanding of these conditions has improved much over the past 10 to 15 years, there remains no specific treatment for pulmonary complications of SCD. It is unclear whether conventional treatment regimens directed at non-SCD populations have equivalent efficacy in patients with SCD. This represents a critical research need. In this review, the authors review the state-of-the-art understanding of the following pulmonary complications of SCD: (1) pulmonary hypertension; (2) venous thromboembolic disease; (3) sleep-disordered breathing; (4) asthma and recurrent wheezing; and (5) pulmonary function abnormalities. This review highlights the advances as well as the knowledge gaps in this field to update clinicians and other health care providers and to garner research interest from the medical community.

Evolution of sickle cell disease from a life-threatening disease of children to a chronic disease of adults: The last 40 years

Over the past 40 years, public health measures such as universal newborn screening, penicillin prophylaxis, vaccinations, and hydroxyurea therapy have led to an impressive decline in sickle cell disease (SCD)-related childhood mortality and SCD-related morbidity in high-income countries. We remain cautiously optimistic that the next 40 years will be focused on meeting current challenges in SCD by addressing chronic complications of SCD to reduce mortality and improve quality of life in a growing population of adults with SCD in high-income countries, while simultaneously decreasing the disparity of medical care between high and low-income countries.

Pediatric Pulmonary Hypertension: Guidelines From the American Heart Association and American Thoracic Society

Pulmonary hypertension is associated with diverse cardiac, pulmonary, and systemic diseases in neonates, infants, and older children and contributes to significant morbidity and mortality. However, current approaches to caring for pediatric patients with pulmonary hypertension have been limited by the lack of consensus guidelines from experts in the field. In a joint effort from the American Heart Association and American Thoracic Society, a panel of experienced clinicians and clinician-scientists was assembled to review the current literature and to make recommendations on the diagnosis, evaluation, and treatment of pediatric pulmonary hypertension. This publication presents the results of extensive literature reviews, discussions, and formal scoring of recommendations for the care of children with pulmonary hypertension.

Low forced expiratory volume is associated with earlier death in sickle cell anemia

Pulmonary complications result in mortality in adults with sickle cell anemia (SCA). We tested the hypothesis that abnormal pulmonary function was associated with earlier death. A prospective cohort of adults with SCA, followed in the Cooperative Study for Sickle Cell Disease, was constructed using the first pulmonary function test at >21 years of age. Spirometry measures: forced expiratory volume in 1 second (FEV1), forced vital capacity, and total lung capacity were categorized based on age, gender, height, and race. Pulmonary function patterns were categorized based on the American Thoracic Society guidelines using both spirometry and lung volumes. A cohort of 430 adults with SCA, mean age 32.6 ± 9.5 (range, 21.0-67.8) years at time of first pulmonary function test, and a median follow-up of 5.5 years, was evaluated. A total of 63 deaths occurred. At baseline, 47% had normal, 29% restrictive, 8% obstructive, 2% mixed, and 14% nonspecific lung function patterns. In the final multivariable model, lower FEV1 percent predicted was associated with increased hazard ratio of death (HR per % predicted 1.02; 95% confidence interval [CI] 1.00-1.04; P = .037), as was older age (HR 1.07; 95% CI 1.04-1.10; P < .001), male sex (HR 2.09; 95% CI 1.20-3.65; P = .010), higher lactate dehydrogenase levels (HR per mg/dL 1.002; 95% CI 1.00-1.003; P = .015), and higher acute chest syndrome incidence rate (HR per event/year 10.4; 95% CI 3.11-34.8; P < .001). Presence of obstructive (HR 1.18; 95% CI: 0.44-3.20; P = .740) and restrictive (HR 1.31; 95% CI: 0.64-2.32; P = .557) pulmonary function patterns were not associated with earlier death. Understanding the pathophysiology of a low FEV1 percent predicted in individuals with SCA is warranted, enabling early intervention for those at risk.

Traffic Light: prognosis-based eligibility for clinical trials of hematopoietic SCT in adults with sickle cell anemia

Estimating prognosis in sickle cell anemia (SCA) assumes greater importance as intensive treatments, such as hematopoietic SCT (HSCT), are being tested. Here we estimate the mortality risk from the walk-PHaSST (Sildenafil Therapy for Pulmonary Hypertension and Sickle Cell Disease) trial of homozygous SCA patients with suspected pulmonary hypertension (19/468 deaths; 10 centers in the US and UK). Parallel investigations were also undertaken in the Cooperative Study of Sickle Cell Disease (CSCCD) and a contemporary urban sickle cell disease population (Case Western Reserve University-University Hospitals (CWRU-UH), Cleveland, OH, USA). One- and two-value positive predictive values for 2-year mortality (from study entry) are calculated using factors that include demographics, laboratory values and clinical evaluations. We define high-, intermediate-, and low-risk SCA as > 15%, 10-15% and < 10% 2-year mortality. In walk-PHaSST, no single factor qualifies as high-risk SCA, although several combinations of two factors (that is, both age > 35 years and history of chronic transfusion) do. Either elevated white blood cell count (> 13.5 × 10(3) cells/mcL, 7/70 deaths) or elevated Tricuspid Regurgitant Jet Velocity (⩾ 3.0 m/s, 8/67 deaths) was individually associated with intermediate-risk disease, as were many two-factor combinations. N-terminal pro-brain natriuretic peptide > 160 ng/L, lactate dehydrogenase > 600 IU/L, history of chronic transfusion, sepsis or age > 35 years are individually associated with low-risk SCA, as are many two-factor combinations. SCA risk was integrated with estimated donor type-associated risk from HSCT to form 'Traffic Light' eligibility criteria for clinical trials of HSCT. This method is adaptable to evolutions in clinical care.

Kinetics of sickle cell biorheology and implications for painful vasoocclusive crisis

We developed a microfluidics-based model to quantify cell-level processes modulating the pathophysiology of sickle cell disease (SCD). This in vitro model enabled quantitative investigations of the kinetics of cell sickling, unsickling, and cell rheology. We created short-term and long-term hypoxic conditions to simulate normal and retarded transit scenarios in microvasculature. Using blood samples from 25 SCD patients with sickle hemoglobin (HbS) levels varying from 64 to 90.1%, we investigated how cell biophysical alterations during blood flow correlated with hematological parameters, HbS level, and hydroxyurea (HU) therapy. From these measurements, we identified two severe cases of SCD that were also independently validated as severe from a genotype-based disease severity classification. These results point to the potential of this method as a diagnostic indicator of disease severity. In addition, we investigated the role of cell density in the kinetics of cell sickling. We observed an effect of HU therapy mainly in relatively dense cell populations, and that the sickled fraction increased with cell density. These results lend support to the possibility that the microfluidic platform developed here offers a unique and quantitative approach to assess the kinetic, rheological, and hematological factors involved in vasoocclusive events associated with SCD and to develop alternative diagnostic tools for disease severity to supplement other methods. Such insights may also lead to a better understanding of the pathogenic basis and mechanism of drug response in SCD.

Pulmonary hypertension in sickle cell disease: diagnosis and management

The increased survival of patients with sickle cell disease (SCD) into adulthood is associated with an increased incidence of multiorgan dysfunction and a progressive systemic and pulmonary vasculopathy. The high prevalence of an elevated tricuspid regurgitant jet velocity and its association with an increased risk of death in adult patients is well established. However, there has been controversy regarding the prevalence of pulmonary hypertension (PH) and its association with mortality in SCD. Multiple recently published reports demonstrate that PH as diagnosed by right heart catheterization is common in adult SCD patients, with a prevalence of 6%–11%. Furthermore, PH is associated with an increased risk of death in SCD patients. In this chapter, we provide evidence for the high prevalence of PH in SCD and its association with mortality and make recommendations for its evaluation and management. Finally, we provide the rationale for screening for this life-threatening complication in adult patients with SCD.

Risk factors for death in 632 patients with sickle cell disease in the United States and United Kingdom

Background

The role of pulmonary hypertension as a cause of mortality in sickle cell disease (SCD) is controversial.

Methods and Results

We evaluated the relationship between an elevated estimated pulmonary artery systolic pressure and mortality in patients with SCD. We followed patients from the walk-PHaSST screening cohort for a median of 29 months. A tricuspid regurgitation velocity (TRV)≥3.0 m/s cuttof, which has a 67–75% positive predictive value for mean pulmonary artery pressure ≥25 mm Hg was used. Among 572 subjects, 11.2% had TRV≥3.0 m/sec. Among 582 with a measured NT-proBNP, 24.1% had values ≥160 pg/mL. Of 22 deaths during follow-up, 50% had a TRV≥3.0 m/sec. At 24 months the cumulative survival was 83% with TRV≥3.0 m/sec and 98% with TRV<3.0 m/sec (p<0.0001). The hazard ratios for death were 11.1 (95% CI 4.1–30.1; p<0.0001) for TRV≥3.0 m/sec, 4.6 (1.8–11.3; p = 0.001) for NT-proBNP≥160 pg/mL, and 14.9 (5.5–39.9; p<0.0001) for both TRV≥3.0 m/sec and NT-proBNP≥160 pg/mL. Age >47 years, male gender, chronic transfusions, WHO class III–IV, increased hemolytic markers, ferritin and creatinine were also associated with increased risk of death.

Conclusions

A TRV≥3.0 m/sec occurs in approximately 10% of individuals and has the highest risk for death of any measured variable.

The study is registered in ClinicalTrials.gov with identifier

NCT00492531

An official American Thoracic Society clinical practice guideline: diagnosis, risk stratification, and management of pulmonary hypertension of sickle cell disease

BACKGROUND

In adults with sickle cell disease (SCD), an increased tricuspid regurgitant velocity (TRV) measured by Doppler echocardiography, an increased serum N-terminal pro-brain natriuretic peptide (NT-pro-BNP) level, and pulmonary hypertension (PH) diagnosed by right heart catheterization (RHC) are independent risk factors for mortality.

METHODS

A multidisciplinary committee was formed by clinician-investigators experienced in the management of patients with PH and/or SCD. Clinically important questions were posed, related evidence was appraised, and questions were answered with evidence-based recommendations. Target audiences include all clinicians who take care of patients with SCD.

RESULTS

Mortality risk stratification guides decision making. An increased risk for mortality is defined as a TRV equal to or greater than 2.5 m/second, an NT-pro-BNP level equal to or greater than 160 pg/ml, or RHC-confirmed PH. For patients identified as having increased mortality risk, we make a strong recommendation for hydroxyurea as first-line therapy and a weak recommendation for chronic transfusions as an alternative therapy. For all patients with SCD with elevated TRV alone or elevated NT-pro-BNP alone, and for patients with SCD with RHC-confirmed PH with elevated pulmonary artery wedge pressure and low pulmonary vascular resistance, we make a strong recommendation against PAH-specific therapy. However, for select patients with SCD with RHC-confirmed PH who have elevated pulmonary vascular resistance and normal pulmonary capillary wedge pressure, we make a weak recommendation for either prostacyclin agonist or endothelin receptor antagonist therapy and a strong recommendation against phosphodiesterase-5 inhibitor therapy.

CONCLUSIONS

Evidence-based recommendations for the management of patients with SCD with increased mortality risk are provided, but will require frequent reassessment and updating.

Differences in the clinical and genotypic presentation of sickle cell disease around the world

Sickle cell disease (SCD), caused by a mutation in the β-globin gene HBB, is widely distributed in malaria endemic regions. Cardiopulmonary complications are major causes of morbidity and mortality. Hemoglobin SS (Hb SS) represents a large proportion of SCD in the Americas, United Kingdom, and certain regions of Africa while higher proportions of hemoglobin SC are observed in Burkina Faso and hemoglobin Sβ-thalassemia in Greece and India. Coinheritance of α-thalassemia and persistence of hemoglobin F production are observed in highest frequency in certain regions of India and the Middle East. As confirmed in the PUSH and Walk-PHaSST studies, Hb SS, absence of co-inheriting alpha-thalassemia, and low hemoglobin F levels tend to be associated with more hemolysis, lower hemoglobin oxygen saturations, greater proportions of elevated tricuspid regurgitant jet velocity and brain natriuretic peptide, and increased left ventricular mass index. Identification of additional genetic modifiers will improve prediction of cardiopulmonary complications in SCD.

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.

Beyond the definitions of the phenotypic complications of sickle cell disease: an update on management

The sickle hemoglobin is an abnormal hemoglobin due to point mutation (GAG → GTG) in exon 1 of the β globin gene resulting in the substitution of glutamic acid by valine at position 6 of the β globin polypeptide chain. Although the molecular lesion is a single-point mutation, the sickle gene is pleiotropic in nature causing multiple phenotypic expressions that constitute the various complications of sickle cell disease in general and sickle cell anemia in particular. The disease itself is chronic in nature but many of its complications are acute such as the recurrent acute painful crises (its hallmark), acute chest syndrome, and priapism. These complications vary considerably among patients, in the same patient with time, among countries and with age and sex. To date, there is no well-established consensus among providers on the management of the complications of sickle cell disease due in part to lack of evidence and in part to differences in the experience of providers. It is the aim of this paper to review available current approaches to manage the major complications of sickle cell disease. We hope that this will establish another preliminary forum among providers that may eventually lead the way to better outcomes.

Cardiovascular abnormalities in sickle cell disease

Sickle cell disease is characterized by recurrent episodes of ischemia-reperfusion injury to multiple vital organ systems and a chronic hemolytic anemia, both contributing to progressive organ dysfunction. The introduction of treatments that induce protective fetal hemoglobin and reduce infectious complications has greatly prolonged survival. However, with increased longevity, cardiovascular complications are increasingly evident, with the notable development of a progressive proliferative systemic vasculopathy, pulmonary hypertension (PH), and left ventricular diastolic dysfunction. Pulmonary hypertension is reported in autopsy studies, and numerous clinical studies have shown that increased pulmonary pressures are an important risk marker for mortality in these patients. In epidemiological studies, the development of PH is associated with intravascular hemolysis, cutaneous leg ulceration, renal insufficiency, iron overload, and liver dysfunction. Chronic anemia in sickle cell disease results in cardiac chamber dilation and a compensatory increase in left ventricular mass. This is often accompanied by left ventricular diastolic dysfunction that has also been a strong independent predictor of mortality in patients with sickle cell disease. Both PH and diastolic dysfunction are associated with marked abnormalities in exercise capacity in these patients. Sudden death is an increasingly recognized problem, and further cardiac investigations are necessary to recognize and treat high-risk patients.