Associations of Prolonged QTc in Sickle Cell Disease

Left ventricular global longitudinal strain and acute myocardial injury in patients with sickle cell disease admitted to the intensive care unit for vaso-occlusive crisis

In patients with sickle cell disease (SCD), SCD-related cardiomyopathy may be partly due to repeated ischaemic events related to sickling during vaso-occlusive crises, but few clinical studies support this hypothesis. We evaluated the incidence of acute myocardial ischaemia during vaso-occlusive crises as assessed by the left ventricular global longitudinal strain (LVGLS) and high-sensitive cardiac troponin T (hs-cTnT). We included adult patients with SCD admitted to the intensive care unit (ICU) for vaso-occlusive crisis. We collected hs-cTnT and measured LVGLS with echocardiography at admission (day 1), day 2, day 3 and ICU discharge. Among 55 patients included, considering only the first hospitalization of patients admitted several times, 3 (5%) had elevated hs-cTnT at ≥1 time point of the ICU stay. It was ≤2 times the upper limit of normal in two of these patients. LVGLS was altered at ≥1 time point of the ICU stay in 13 (24%) patients. Both hs-cTnT and LVGLS were abnormal at ≥1 time point of the hospital stay in 2 (4%) patients. Acute myocardial injury as assessed by troponin elevation and LVGLS impairment was a rare event during vaso-occlusive crises.

Electrocardiographic abnormalities in patients with sickle cell disease: A systematic review and meta-analysis

BACKGROUND

Previous studies have documented that electrocardiography (ECG) can reveal a range of abnormalities, offering valuable insights into the cardiac evaluation of patients with sickle cell disease (SCD). The objective of this study is to assess the patterns of ECG abnormalities observed in these patients with SCD, and to determine their prevalence.

METHOD

We systematically reviewed the literature using online databases of PubMed, Scopus, Web of Science, Embase, and Google Scholar to identify original studies that reported findings of standard ECG assessments in patients with SCD. Statistical analyses were performed using the random effects model. Additional analyses including sensitivity analysis and subgroup analysis were also conducted.

RESULTS

Analysis of data from 59 studies involving 897,920 individuals with SCD revealed that 75% of these patients had abnormal ECG findings (67%-81%), which were predominantly nonspecific ST-T changes, left ventricular hypertrophy, T-wave changes, prolonged corrected QT (QTc) interval, and ischemic changes. Besides, it was shown that these patients had significantly higher odds of having any ECG abnormalities (OR of 17.50, 4.68-65.49), right atrial enlargement (6.09, 1.48-25.09), left ventricular hypertrophy (3.45, 1.73-6.89), right ventricular hypertrophy (7.18, 2.28-22.57), biventricular hypertrophy (10.11, 1.99-51.38), prolonged QTc interval (5.54, 2.44-12.59), ST depression (3.34, 1.87-5.97), and T-wave changes (5.41, 1.43-20.56). Moreover, the mean of QTc interval was significantly higher among those with SCD (23.51 milliseconds, 16.08-30.94).

CONCLUSION

Our meta-analysis showed a higher prevalence of abnormal ECG findings among individuals with SCD. A significant proportion of these patients had various ECG abnormalities, suggesting a potential need for regular ECG assessments for patients with SCD.

Genetic variants and effect modifiers of QT interval prolongation in patients with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is a common inherited blood disorder among African Americans (AA), with premature mortality which has been associated with prolongation of the heart rate-corrected QT interval (QTc), a known risk factor for sudden cardiac death. Although numerous genetic variants have been identified as contributors to QT interval prolongation in the general population, their impact on SCD patients remains unclear. This study used an unweighted polygenic risk score (PRS) to validate the previously identified associations between SNPs and QTc interval in SCD patients, and to explore possible interactions with other factors that prolong QTc interval in AA individuals with SCD.

METHODS

In SCD patients, candidate genetic variants associated with the QTc interval were genotyped. To identify any risk SNPs that may be correlated with QTc interval prolongation, linear regression was employed, and an unweighted PRS was subsequently constructed. The effect of PRS on the QTc interval was evaluated using linear regression, while stratification analysis was used to assess the influence of serum alanine transaminase (ALT), a biomarker for liver disease, on the PRS effect. We also evaluated the PRS with the two subcomponents of QTc, the QRS and JTc intervals.

RESULTS

Out of 26 candidate SNPs, five risk SNPs were identified for QTc duration under the recessive model. For every unit increase in PRS, the QTc interval prolonged by 4.0 ms (95% CI: [2.0, 6.1]; p-value: <0.001) in the additive model and 9.4 ms in the recessive model (95% CI: [4.6, 14.1]; p-value: <0.001). Serum ALT showed a modification effect on PRS-QTc prolongation under the recessive model. In the normal ALT group, each PRS unit increased QTc interval by 11.7 ms (95% CI: [6.3, 17.1]; p-value: 2.60E-5), whereas this effect was not observed in the elevated ALT group (0.9 ms; 95% CI: [-7.0, 8.8]; p-value: 0.823).

CONCLUSION

Several candidate genetic variants are associated with QTc interval prolongation in SCD patients, and serum ALT acts as a modifying factor. The association of a CPS1 gene variant in both QTc and JTc duration adds to NOS1AP as evidence of involvement of the urea cycle and nitric oxide metabolism in cardiac repolarization in SCD. Larger replication studies are needed to confirm these findings and elucidate the underlying mechanisms.

Clinical and Laboratory Correlates of QTc Duration in Adult and Pediatric Sickle Cell Disease

Background

Sickle cell disease, a common genetic disorder in African Americans, manifests an increased risk of sudden death, the basis of which is incompletely understood. Prolongation of heart rate-corrected QT (QTc) interval on the electrocardiogram, a standard clinical measure of cardiac repolarization, may contribute to sudden death by predisposing to torsades de pointes ventricular tachycardia.

Methods

We established a cohort study of 293 adult and 121 pediatric sickle cell disease patients drawn from the same geographic region as the Jackson Heart Study (JHS) cohort, in which significant correlates of QT duration have been characterized and quantitatively modeled. Herein, we establish clinical and laboratory correlates of QTc duration in our cohort using stepwise multivariate linear regression analysis. We then compared our adult sickle cell disease data to effect-size predictions from the published JHS statistical model of QT interval duration.

Results

In adult sickle cell disease, gender, diuretic use, QRS duration, serum ALT levels, anion gap, and diastolic blood pressure show positive correlation; hemoglobin levels show inverse correlation; in pediatric sickle cell disease, age, hemoglobin levels, and serum bicarbonate and creatinine levels show inverse correlation. The mean QTc in our adult sickle cell disease cohort is 7.8 milliseconds longer than in the JHS cohort, even though the JHS statistical model predicts that the mean QTc in our cohort should be > 11 milliseconds shorter than in the much older JHS cohort, a differential of > 18 milliseconds.

Conclusion

Sickle cell disease patients have substantial QTc prolongation relative to their age, driven by factors some overlapping, in adult and pediatric sickle cell disease, and distinct from those that have been defined in the general African American community.

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.

Cardiopulmonary changes in patients with sickle cell anemia: A systematic review

BACKGROUND

Given the high prevalence of cardiovascular and pulmonary abnormalities associated with sickle cell anemia (SCA), the clinical impact caused in addition to compromising the quality of life of patients and the overcharge that it represents to the public health system, this study systematized and evaluated scientific publications on pulmonary complications and cardiovascular diseases in sickle cell patients from 1920 to 2020. This compilation aims to provide knowledge for health professionals and managers in order to draw attention to the importance of chronic diseases in SCA patients and in addition to providing elements that provide improvements in management of useful resources that contribute to improve the quality and increase the life expectancy of these patients.

AIM

To systematically compile information about cardiopulmonary changes in patients with SCA.

METHODS

A systematic literature review was performed based on the PRISMA recom-mendation including scientific articles indexed in the Scientific Electronic Library Online databases of the United States National Library of Medicine and Biblioteca Virtual de Saúde. The search period was delimited between 1990 and 2020 and selected in Portuguese, English and Spanish. Three sets of descriptors were used for each database including research carried out with human beings. After reading the articles, those useful for this review were extracted using a collection instrument designed for this purpose.

RESULTS

The final selection included 27 studies. The year with the highest number of publications was 2016 with 5 studies (18.51%), followed by 2017 with 4 (14.81%). The type of study most carried out in the period was cohort 10 (37.03%) followed by cross-sectional and case-control with 8 studies in each (29.62%). Regarding the language of publication, the distribution was as follows: 25 (92.59%) in English, 1 (3.70%) in Spanish and 1 (3.70%) in Portuguese.

CONCLUSION

The findings of the present study suggest that cardiopulmonary alterations represent a serious clinical repercussion of SCA. Of the analyzed studies, the high occurrence of pulmonary hypertension, ventricular hypertrophy and diastolic dysfunction stands out as the main cardiopulmonary complications. In view of the increased survival in SCA, there is a need for surveillance and the development of strategies aimed at preserving the cardiopulmonary function and consequently improving the quality of life of these patients.

Protocol-based cardiotoxicity monitoring in hydroxychloroquine medicated COVID-19 pediatric patients

Introduction/objectives

By May 2020, SARS-CoV-2 had caused more than 400 000 deaths worldwide. Initially, hydroxychloroquine was a treatment option for COVID-19. More recent studies have questioned its safety and efficacy and, until stronger evidence is available, it was suspended from therapy protocols. We describe our experience treating COVID-19 Portuguese pediatric patients with hydroxychloroquine, having applied a protocol for monitoring cardiac toxicity.

Methods

An observational retrospective study of COVID-19 pediatric patients, admitted from March to April 2020 and treated with hydroxychloroquine. Cardiotoxicity was assessed using ECG recordings and corrected QT-time (QTc). Patients were classified into risk-groups depending on QTc value: normal, slightly elevated or severely elevated (>500 ms).

Results

Total of 14 patients, with a median age of 10 years [four months; 17 years], treated with hydroxychloroquine for a median of five days. Hydroxychloroquine was used in monotherapy in six patients (mainly mild disease with comorbidities), and in association with lopinavir/ritonavir (3) and azithromycin (5) in moderate to severe disease. Other QT-prolonging therapies were used in five patients: oseltamivir (3), omeprazole (1), morphine (1) and ketamine (1). At 48 hours of treatment, two patients temporarily suspended hydroxychloroquine due to QTc prolongation (>500 ms). All patients completed the whole treatment. No other side effects or deaths occurred.

Conclusion

Clinical trials are evolving to define hydroxychloroquine effectivity and safety. Our considerable pediatric population supports the need for cardiotoxicity monitoring during therapy but suggest its use seems to be safe in COVID-19 pediatric patients, even in association with other QT-prolonging therapies.

Prolonged QTc Interval in Nigerian Children with Sickle Cell Anemia

Prolonged QTc interval, a risk factor for ventricular arrhythmia, occurs in sickle cell anemia. The aim of this study was to determine the risk of prolonged QTc interval and its relationship with vaso-occlusive painful crises (VOCs) and follow-up steady-state in the same children with sickle cell anemia. This prospective cohort study enrolled 38 subjects, aged 5-17 years. History of bone pain and examination were obtained during VOC and steady-state. Assessment of QTc interval was with 12-lead electrocardiography. The QTc interval value >0.440 seconds was taken as prolonged. Median (interquartile range) of QTc interval was higher during VOC [0.447 (0.438-0.459) seconds] than during steady-state [0.435 (0.417-0.440) seconds]. Risk of prolonged QTc interval was higher during VOC (68.4%) than in steady-state (21.1%) with relative risk of 3.250 [95% confidence interval (CI) = 1.692-6.241]. Prolonged QTc interval was likely to occur [area under curve (AUC) = 0.759, p<0.001] during VOC with 68.4% sensitivity, 78.9% specificity and at cutoff point of 0.441 seconds. Prolonged QTc interval negatively correlated with packed cell volume (PCV) during VOC [r_s (36) = -0.14, p = 0.387]. Binary logistics of the combined effect of PCV and gender on QTc interval showed that during VOC, males were more likely to have prolonged QTc [odds ratio (OR): 1.337 (95% CI: 0.327-5.464; p = 0.686]. Children with sickle cell anemia, particularly males, were three-times more likely to have prolonged QTc interval during VOC when QTc interval was >0.441 seconds. Routine electrocardiography may help to identify those with QTc intervals above this threshold for prompt cardiac-oriented management.

Relationship Between Disease Severity and Resting Electrocardiograms of Adults With Sickle Cell Anemia in a Tertiary Institution in Southern Nigeria

Introduction

Sickle cell anemia (SCA) in adults has many clinical manifestations. These manifestations are due to effects of recurrent hemolysis, anemia, and ischemia-reperfusion injury on various organs, including the heart. These factors determine the severity of the disease.

Objectives

The aim of the study was to assess the severity of SCA using a scoring system consisting of clinical and laboratory parameters. In addition, the study aimed to determine the electrocardiographic abnormalities in the adult SCA population.

Study design

This was a cross-sectional, observational study conducted in the medical outpatient clinic of Irrua Specialist Teaching Hospital, Irrua, Nigeria.

Methodology

Sixty SCA patients who were older than 18 years old were recruited for this study between February 2017 and January 2018. Sixty healthy individuals matched for age and sex were recruited to serve as controls. Patients who were pregnant or having an acute crises were excluded from the study. Each participant had an electrocardiogram and a SCA severity score was calculated using their clinical history and complete blood count. Data analysis was carried out using the IBM Statistical Package for Social Sciences Statistics® software, version 21 (IBM SPSS Statistics for Windows, Armonk, NY) and statistical significance assigned to p-values less than 0.05.

Results

Severity scores for SCA ranged between 7 and 24, with a mean score of 14.5 ± 4.04. Out of the 60 patients, 14 (23.3%), 39 (65%), and seven (11.7%) participants met criteria for mild, moderate, and severe disease, respectively. Tachycardia, prolonged QTc, and the presence of ST-segment and T-wave abnormalities were significantly associated with severe SCA (p = 0.024, p = 0.027, and p = 0.018, respectively). There was positive correlation between SCA severity scores and P-wave duration (r = 0.327, p = 0.011), QRS dispersion (r = 0.298, p = 0.021), QTc interval (r = 0.332, p = 0.010), and QTc dispersion (r = 0.320, p = 0.013).

Conclusion

This study demonstrated that moderate and severe forms of SCA are common in our region. Tachycardia, left atrial abnormality, prolonged corrected QT interval, and the presence of ST-segment and T-wave changes are electrocardiographic findings associated with more severe forms of the disease. These abnormalities are significant etiologies of cardiac morbidity and mortality in SCA.

IL-18 mediates sickle cell cardiomyopathy and ventricular arrhythmias

Previous reports indicate that IL18 is a novel candidate gene for diastolic dysfunction in sickle cell disease (SCD)-related cardiomyopathy. We hypothesize that interleukin-18 (IL-18) mediates the development of cardiomyopathy and ventricular tachycardia (VT) in SCD. Compared with control mice, a humanized mouse model of SCD exhibited increased cardiac fibrosis, prolonged duration of action potential, higher VT inducibility in vivo, higher cardiac NF-κB phosphorylation, and higher circulating IL-18 levels, as well as reduced voltage-gated potassium channel expression, which translates to reduced transient outward potassium current (Ito) in isolated cardiomyocytes. Administering IL-18 to isolated mouse hearts resulted in VT originating from the right ventricle and further reduced Ito in SCD mouse cardiomyocytes. Sustained IL-18 inhibition via IL-18-binding protein resulted in decreased cardiac fibrosis and NF-κB phosphorylation, improved diastolic function, normalized electrical remodeling, and attenuated IL-18-mediated VT in SCD mice. Patients with SCD and either myocardial fibrosis or increased QTc displayed greater IL18 gene expression in peripheral blood mononuclear cells (PBMCs), and QTc was strongly correlated with plasma IL-18 levels. PBMC-derived IL18 gene expression was increased in patients who did not survive compared with those who did. IL-18 is a mediator of sickle cell cardiomyopathy and VT in mice and a novel therapeutic target in patients at risk for sudden death.

Sickle cell disease-associated arrhythmias and in-hospital outcomes: Insights from the National Inpatient Sample

BACKGROUND

The frequency and temporal trend in the prevalence of arrhythmias and associated in-hospital outcomes in patients with sickle cell disease (SCD) have never been quantified.

METHODS

Our study cohort of SCD patients and sub-types of arrhythmias were derived from the 2010-2014 National Inpatient Sample using relevant diagnostic codes. The frequency and trends of arrhythmia and odds of inpatient mortality were measured.

RESULTS

A total of 891 450 hospitalized SCD patients were identified, of which, 55 616 (6.2%) patients experienced arrhythmias. The SCD cohort with arrhythmia demonstrated higher all-cause mortality (2.7% vs 0.4%; adjusted OR 2.53, 95% CI 2.15-2.97, P < .001), prolonged hospital stays (6.9 vs 5.0 days) and higher hospital charges ($53 871 vs $30 905) relative to those without arrhythmias (P < .001).The frequency of supraventricular arrhythmia (AFib, SVT, and AF) and ventricular arrhythmia (VFib and VT) were 1893 and 362 per 100 000 SCD-related admissions, respectively. Unspecified arrhythmias (4126) were seen most frequently followed by AFib (1622) per 100 000 SCD-related admissions. From 2010 to 2014, the frequency of any arrhythmias and atrial fibrillation in hospitalized SCD patients relatively increased by 29.6% and 38.5%, respectively. There was nearly a twofold (2.4% in 2010 to 5.0% in 2014) increase in the frequency of arrhythmia among patients aged <18 years. The frequency of arrhythmias in hospitalized male and female SCD patients relatively increased by 28.8% and 31.4%, respectively (P trend < .001).

CONCLUSIONS

The frequency of arrhythmias among SCD patients is on the rise with worse hospitalization outcomes, including higher in-hospital mortality and higher resource utilization as compared to those without arrhythmias.

Reversal of a rheologic cardiomyopathy following hematopoietic stem cell transplantation for sickle cell disease

Cardiac complications have been well-described in sickle cell disease; however, it has been rare to see improvements in cardiac abnormalities following any interventions. Previous work has shown no significant structural changes after treatment with hydroxyurea. The cardiac effects of red blood cell exchange transfusion (RBCx) and hematopoietic stem cell transplantation (HSCT) have not been well described. We studied 56 patients undergoing HSCT (41 HLA-matched, 15 haploidentical), of whom 32 had RBCx within 3 months before HSCT. Echocardiograms and laboratory parameters were obtained at baseline, and at 3, 6, and 12 months following HSCT. Although hemolytic parameters and anemia improved following RBCx, there was a small increase in left ventricular volume index. Following successful HSCT, however, there were significant improvements in cardiac size, function, and diastolic filling parameters at 3 months followed by continued smaller improvements up to 1 year. There was a significant improvement in N-terminal pro B-type natriuretic peptide levels and a trend toward improvement in 6-minute walk time 1 year after HSCT. The magnitude of cardiac improvement seen following HSCT was comparable to that observed following correction of a volume overload state as seen in pregnancy or after repair of chronic valvular regurgitation. Further studies in sickle cell disease patients will help delineate which cardiac complications and what level of severity should be considered indications for HSCT.

Impact of relative systemic hypertension on the heart in sickle cell anaemia

Sickle cell anaemia (SCA) is associated with macrovascular complications at relatively normal blood pressures. This has led to the development of the term 'relative systemic hypertension' (RSH). The electrocardiography (ECG) and echocardiography (ECHO) findings in these people has not been well highlighted. Patients with SCA in steady state were consecutively recruited. History, physical examination, ECG and ECHO information were obtained from all participants after informed consent was obtained. Eighty-three people were recruited in all- 15 of which had RSH, giving a prevalence of 18.1%. Those with RSH had higher packed cell volumes (PCV), smaller right atria area, lower tricuspid regurgitant velocities, lower incidence of early satiety, longer QTc and higher frequency of a history of vaso-occlusive crises. The indices of right and left ventricular function were normal in both groups. Right atrial area was the only significant determinant of RSH in this study. RSH is associated with higher PCV, longer QTc and smaller right atrial area in SCA patients. More studies to evaluate sympathetic output in SCA with RSH is required.

Cardiovascular Sequelae of Sickle Cell Disease

Sickle cell disease (SCD) is one of the most common hereditary hemoglobinopathies worldwide. It is a multisystem disease that causes considerable patient morbidity. Despite advances in medical treatment, cardiopulmonary complications remain the most common cause of death in individuals with SCD. A growing body of evidence has shown that SCD results in a spectrum of cardiovascular complications through a variety of mechanisms, including chronic hemolysis, local tissue hypoxia, increased oxidative stress, and autonomic instability. Herein, we will examine the pathophysiology of sickle cell vasculopathy and discuss the spectrum of cardiovascular sequelae of the disease, while highlighting the impact of SCD on the cardiovascular health of the patients.

Cardiovascular complications of sickle cell disease

Sickle cell disease (SCD) is the most common inherited blood disorder in the United States, and a global health problem. Pathological features of the abnormal hemoglobin (HbS) result in 2 hallmarks of the disease - recurrent episodes of acute microvascular occlusion and chronic hemolytic anemia - that inflict continuous and insidious damage to multiple organs. With improved childhood survival, SCD in adults has evolved into a chronic degenerative disease with underlying damage to multiple organs including the heart and lungs. Cardiopulmonary complications, including cardiomyopathy, diastolic dysfunction, pulmonary hypertension (PH), and sudden cardiac death are the most common causes of morbidity and mortality. Awareness of the sickle-related cardiovascular phenotypes is important for screening, early diagnosis, and intervention of cardiac complications in this disorder.

Cardiovascular manifestations of sickle cell disease

Sickle cell disease (SCD) is the most frequent genetic haemoglobinopathy worldwide. Early childhood mortality has dramatically decreased in high-income countries, and most patients now survive beyond the 5th decade. However, in the aging SCD population, the morbidity related to chronic organ damage, especially kidney and heart, has become a major concern. While pulmonary hypertension has attracted most attention, it appears that this condition is frequently linked to left heart failure (HF). Accordingly, SCD-associated cardiomyopathy is emerging as a major cause of reduced quality of life and early mortality in these patients. The diagnosis of this particular phenotype of high-output HF is challenging. Exercise intolerance and dyspnoea in SCD patients are linked to multiple causes including chronic anaemia. Moreover, echocardiographic features are unusual and can be misinterpreted. The classical diagnosis algorithm for HF is generally not suitable in SCD patients, and HF is poorly recognized and mostly diagnosed at a late congestive stage in routine practice. Such patients need to be identified at an earlier stage of myocardial dysfunction via improved phenotyping. This constitutes the first step towards further investigations in SCD needed to improve the prognosis and the quality of life. This article provides an updated review of the recent advances in the pathophysiology and diagnosis, and in addition, perspectives of new therapeutic approaches in SCD-related cardiac manifestations.

Association of circulating transcriptomic profiles with mortality in sickle cell disease

Sickle cell disease (SCD) complications are associated with increased morbidity and risk of mortality. We sought to identify a circulating transcriptomic profile predictive of these poor outcomes in SCD. Training and testing cohorts consisting of adult patients with SCD were recruited and prospectively followed. A pathway-based signature derived from grouping peripheral blood mononuclear cell transcriptomes distinguished 2 patient clusters with differences in survival in the training cohort. These findings were validated in a testing cohort in which the association between cluster 1 molecular profiling and mortality remained significant in a fully adjusted model. In a third cohort of West African children with SCD, cluster 1 differentiated SCD severity using a published scoring index. Finally, a risk score composed of assigning weights to cluster 1 profiling, along with established clinical risk factors using tricuspid regurgitation velocity, white blood cell count, history of acute chest syndrome, and hemoglobin levels, demonstrated a higher hazard ratio for mortality in both the training and testing cohorts compared with clinical risk factors or cluster 1 data alone. Circulating transcriptomic profiles are a powerful method to risk-stratify severity of disease and poor outcomes in both children and adults, respectively, with SCD and highlight potential associated molecular pathways.