Evaluation of microstructural changes in the brain in transfusion dependent thalassemia patients with advanced magnetic resonance imaging techniques.

PURPOSE: Transfusion-dependent thalassemia (TDT) is associated with iron accumulation in the body and an increased tendency for thrombosis. With the increased life expectancy in these patients, the detection of neurocognitive complications has gained importance. This study investigates the microstructural changes in TDT patients using advanced diffusion MRI techniques and their relationship with laboratory parameters. METHODS: The study included 14 TDT patients and 14 control subjects. Tract-based spatial statistics (TBSS) were used to examine differences in DTI parameters such as fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in thalassemia patients using multi-shell DWI images. The mean kurtosis (MK) difference was investigated using diffusion kurtosis imaging. Fiber density (FD), fiber cross-section (FC), and fiber density and cross-section (FDC) differences were examined using fixel-based analysis. In the patient group, correlative tractography was used to investigate the relationship between DTI parameters and platelet (PLT) and ferritin levels. RESULTS: Increase in RD and MD was observed, particularly in the white matter tracts of the corona radiata in patient group. Additionally, an increase in AD was detected in a limited area. Correlative tractography in thalasemia patients showed a positive correlation between increases in RD, MD, and AD with PLT and ferritin. Fixel-based analysis demonstrated a dispersed distribution in white matter fibers, with a more pronounced decrease in FD, FC, and FDC in the internal capsule. CONCLUSION: There is widespread involvement in the white matter and fiber tracts in thalassemia patients, which is highly correlated with thrombotic parameters.

Quantification of cardiac iron in patients with thalassemia with 3-T MRI calibrated by 1.5-T MRI.

BACKGROUND: Due to the small sample size of many studies, it remained unclear what standardized reference range the T2* cutoff at 3 T would be used to assess the severity of cardiac iron load. In addition, the number of patients with moderate to severe cardiac iron load was small in some studies, especially the sample of patients with severe cardiac iron load. PURPOSE: To explore the feasibility, reproducibility, and reliability of using T2* values in quantifying cardiac iron load in patients with thalassemia at 3 T. MATERIAL AND METHODS: A total of 122 patients with thalassemia underwent cardiac T2* imaging at both 1.5 T and 3 T. Cardiac R2* (1000/T2*) values of the 100 patients at 3 T were fitted against the values at 1.5 T using linear regression and the prediction equation was derived. The remaining 22 cases were used to test the prediction accuracy of the equation. RESULTS: The combined R2* values exhibited a strong linear relationship between 1.5 T and 3 T (r = 0.830，P<0.001). At the center, it had a slope of 1.348 and an intercept of 37.279. According to the equation, the truncated T2* values of cardiac iron overload and cardiac heavy iron overload at 3 T were <10 ms and <6 ms, respectively. The two truncated T2* values were used to diagnose different levels of cardiac iron overloaded of 22 patients at 3 T; the accuracy rates were 95.5% and 100.0%, respectively. CONCLUSION: T2* quantification of cardiac iron load at 3 T MRI resulted to be feasible, reproducible, and reliable.

Left Ventricular Myocardial Dysfunction Evaluation in Thalassemia Patients Using Echocardiographic Radiomic Features and Machine Learning Algorithms.

Heart failure caused by iron deposits in the myocardium is the primary cause of mortality in beta-thalassemia major patients. Cardiac magnetic resonance imaging (CMRI) T2* is the primary screening technique used to detect myocardial iron overload, but inherently bears some limitations. In this study, we aimed to differentiate beta-thalassemia major patients with myocardial iron overload from those without myocardial iron overload (detected by T2*CMRI) based on radiomic features extracted from echocardiography images and machine learning (ML) in patients with normal left ventricular ejection fraction (LVEF > 55%) in echocardiography. Out of 91 cases, 44 patients with thalassemia major with normal LVEF (> 55%) and T2* ≤ 20 ms and 47 people with LVEF > 55% and T2* > 20 ms as the control group were included in the study. Radiomic features were extracted for each end-systolic (ES) and end-diastolic (ED) image. Then, three feature selection (FS) methods and six different classifiers were used. The models were evaluated using various metrics, including the area under the ROC curve (AUC), accuracy (ACC), sensitivity (SEN), and specificity (SPE). Maximum relevance-minimum redundancy-eXtreme gradient boosting (MRMR-XGB) (AUC = 0.73, ACC = 0.73, SPE = 0.73, SEN = 0.73), ANOVA-MLP (AUC = 0.69, ACC = 0.69, SPE = 0.56, SEN = 0.83), and recursive feature elimination-K-nearest neighbors (RFE-KNN) (AUC = 0.65, ACC = 0.65, SPE = 0.64, SEN = 0.65) were the best models in ED, ES, and ED&ES datasets. Using radiomic features extracted from echocardiographic images and ML, it is feasible to predict cardiac problems caused by iron overload.

Thalassemia in the emergency department: special considerations for a rare disease.

Thalassemia is characterized by a defect in the synthesis of one or more of the globin subunits of hemoglobin. This defect results in imbalance in the α/ß-globin chain ratio, ineffective erythropoiesis, chronic hemolytic anemia, and iron overload. With advances in diagnosis, treatment, and transfusion support, the prognosis of patients with thalassemia has improved over the past few decades. An increasing number of patients with thalassemia is living with long-term complications, including cardiomyopathy, chronic liver disease, endocrinopathy, and infections. In this paper, we review common complications that bring the patient with thalassemia to urgent or emergent medical attention. We also discuss the aspects of emergency care that are most relevant while caring for the patient with thalassemia in the emergency department.

N-acetylcysteine Restored Heart Rate Variability and Prevented Serious Adverse Events in Transfusion-dependent Thalassemia Patients: a Double-blind Single Center Randomized Controlled Trial.

Regular blood transfusions in transfusion-dependent thalassemia (TDT) patients can lead to iron overload, causing oxidative stress and sympathovagal imbalance, resulting in increased cardiac complications. We hypothesized that administrating of N-acetylcysteine (NAC) prevents serious adverse events including cardiac complications in TDT patients by reducing systemic oxidative stress and balancing cardiac sympathovagal control. This study was double-blind, randomized control trial, investigating in 59 Thai TDT patients. After randomization, the participants were divided into two groups. The control group received standard care of TDT patient plus placebo, whereas the intervention group received 600 mg of NAC orally for six months. Serum 8-isoprostane, TNF-alpha, IL-10, 24-hour ECG monitoring, echocardiograms and the incidence of thalassemia-related complications were collected. At baseline, no significant difference in any parameters between the control and the intervention groups. At the end of intervention, the incidence of serious adverse events (i.e. infection, worsening thalassemia) was significantly higher in the control group when compared with the intervention group (24.1% vs. 3.3%, p=0.019) (Chi-square test; absolute risk reduction=20.8%, number needed to treat=4.8). The control group also had significantly lower time-dependent HRV parameters, compared with the intervention group (p=0.025 and 0.030, independent t-test). Treatment with NAC restored HRV and reduced serious adverse event in TDT patients, however, no difference in cardiac complications could be demonstrated. NAC could prevent serious adverse events in TDT patients. The proposed mechanism might be the balancing of sympathovagal control.

Comparative effectiveness of alendronate and zoledronic acid on bone mass improvement in transfusion-dependent thalassemia patients.

Thalassemia, as the most prevalent genetic blood disorder, has many associated comorbidities including low bone mass. We studied the comparative effectiveness of alendronate (AL) and zoledronic acid (ZOL) on bone mass improvement in transfusion-dependent thalassemia (TDT) patients a year after treatment. Three hundred seventy-five TDT patients with low bone mass were enrolled in this study. After a year of treatment with either AL or ZOL, a second bone mineral density (BMD) test was ordered to compare the effectiveness of the two aforementioned drugs. Body mass index (BMI), physical activity, sun exposure, and biochemical laboratory data were also considered as associated factors in this study. The BMD test of both groups was almost the same at the baseline and it increased comparably after a year of treatment with AL and ZOL. However, there was a significant difference in lumbar spine BMD delta Z score between both groups of female patients. ZOL was more effective in increasing the lumbar spine BMD of female patients. The choice of bisphosphonates therapy (oral versus parenteral) should be individually selected by considering patient's preference, compliance and the physician's decision. Given the longer administration interval, and TDT patients' compliance issue, it is justified to recommend ZOL as the drug of choice for patients suffering from low bone mass.

Imbalance of erythropoiesis and iron metabolism in patients with thalassemia.

Aim: This study aimed to evaluate the imbalance of erythropoiesis and iron metabolism in patients with thalassemia. Methods: 192 patients with non-transfusion-dependent thalassemia (NTDT), 94 patients with transfusion-dependent thalassemia (TDT) and 101 healthy controls were recruited between June 2013 and December 2016 in the Hematology Department, the First Affiliated Hospital of Guangxi Medical University. The groups were compared in terms of levels of erythropoiesis biomarkers [growth differentiation factor 15 (GDF15), erythropoietin (EPO) and soluble transferrin receptor (sTfR)] and of iron overload biomarkers [serum ferritin (SF), liver iron concentration (LIC) and cardiac T2*] and hepcidin. Results: The levels of GDF15, EPO, sTfR, LIC and SF were significantly higher in patients with thalassemia. The levels of GDF15 and EPO were significantly higher in patients with TDT compared to NTDT. Those with iron overload had higher EPO, GDF15, SF and sTfR levels compared with non-iron overload patients. Hepcidin levels and ratios of hepcidin to erythropoietic activity and to iron biomarker levels were lower in patients with ß-thalassemia intermedia or hemoglobin (Hb) E/ß-thalassemia than in patients with HbH disease. The hepcidin levels were correlated negatively with the levels of EPO, GDF15 and sTfR in patients with NTDT and TDT, but correlated positively with SF and Hb levels only in patients with TDT. Conclusions: Patients with thalassemia showed iron overload, reduced hepcidin levels, and a greater extent of ineffective erythropoiesis. The hepcidin levels were more strongly related to ineffective erythropoiesis compared with iron overload. The imbalance between erythropoiesis and iron metabolism differed across different thalassemia types.

Comparison of Deferiprone to Deferasirox and Deferoxamine to Cardiac and Hepatic T2* MRI in Thalassemia Patients: Evidence-based Case Report.

BACKGROUND: there are currently three iron chelator readily available for patients Indonesia; deferiprone/DFP (branded as Ferriprox), deferasirox/DFX (branded as Exjade) and deferoxamine/DFO (branded as Desferal). This study aims to determine which iron chelator is the most efficient in reducing cardiac and hepatic iron overload (measured by means of T2* MRI). METHODS: journal search with determined MeSH term was done in PubMed and Scopus. Studies that looked upon thalassemia major patient in all ages with usage of monotherapy iron chelation and its effect on myocardial T2* MRI and/or liver T2* MRI was included. Appraisal of studies was done using Oxford's CEBM appraisal tools and Joanna Brigs Institute critical appraisal tools. RESULTS: total of 11 studies with grand total of 611 samples were included. Mean T2* MRI value or (when available) mean changes in T2* MRI value after usage of specific iron chelator was gained from all the studies included. Comparison study and individual studies shows better control and increase of myocardial T2* MRI in those with DFP, and of liver T2* in those with good adherence to DFO chelation. CONCLUSION: DFP is superior in controlling or reducing myocardial iron load (as proven by mT2* MRI) and DFO had better capabilities in controlling or reducing hepatic iron load (as proven by liver T2* MRI). Studies with longer observation and larger samples is needed to see a significant changes of T2* MRI in DFX.

Progression of liver fibrosis can be controlled by adequate chelation in transfusion-dependent thalassemia (TDT).

A substantial proportion of patients with transfusion-dependent beta-thalassemia major suffer from chronic liver disease. Iron overload resulting from repeated transfusions and HCV infection has been implicated in the development of liver fibrosis. Hepatic siderosis and fibrosis were assessed in 99 transfusion-dependent thalassemia (TDT) patients using transient elastography (TE) and liver iron concentration (LIC) assessed by T2*MRI at baseline and after 4 years. Data were analyzed retrospectively. At baseline, the overall mean liver stiffness measurement (LSM) was 7.4 ± 3.2 kPa and the mean LIC was 4.81 ± 3.82 mg/g dw (n = 99). Data available at 4 ± 1.5 years showed a significant reduction in LSM (6.6 ± 3.2 kPa, p 0.017) and hepatic siderosis measured by LIC (3.65 ± 3.45 mg/g dw, p 0.001). This result was confirmed when considering patients with iron overload at the time of the first measurement (n = 41) and subjects treated with a stable dose of deferasirox over the entire period of observation (n = 39). A reduction of LSM, yet not statistically significant, was achieved in patients on combined deferoxamine + deferiprone, while the group on deferoxamine (n = 11) remained stable over time. HCV-RNA positivity was found in 33 patients at T0, 20 of which were treated during the observation period. Patients who underwent anti-HCV therapy showed a more evident reduction in LSM (9 ± 3 vs 7 ± 3.1 kPa, p 0.016). Adequate chelation therapy is mandatory in order to prevent liver disease progression in TDT. Patients could benefit from regular non-invasive assessment of liver fibrosis by TE to indirectly monitor treatment adequacy and therapeutic compliance.

Effect of Iron Chelation Therapy on Glucose Metabolism in Non-Transfusion-Dependent Thalassaemia.

AIMS: To compare insulin sensitivity, ß-cell function and iron status biomarkers in non-transfusion-dependent thalassaemia (NTDT) with iron excess during pre- and post-iron chelation. METHODS: Subjects with NTDT, aged older than 10 years, with serum ferritin >300 ng/ml, were included. Iron chelation with deferasirox (10 mg/kg/day) was prescribed daily for 6 months. RESULTS: Ten patients with a median age of 17.4 years were enrolled. The comparison between pre- and post-chelation demonstrated significantly lower iron load: median serum ferritin (551.4 vs. 486.2 ng/ml, p = 0.047), median TIBC (211.5 vs. 233.5 µg/dl, p = 0.009) and median non-transferrin binding iron (5.5 vs. 1.4 µM, p = 0.005). All patients had a normal oral glucose tolerance test (OGTT) both pre- and post-chelation. However, fasting plasma glucose was significantly reduced after iron chelation (85.0 vs.79.5 mg/dl, p = 0.047). MRI revealed no significant changes of iron accumulation in the heart and liver after chelation, but there was a significantly lower iron load in the pancreas, assessed by higher T2* at post-chelation compared with pre-chelation (41.9 vs. 36.7 ms, p = 0.047). No adverse events were detected. CONCLUSIONS: A trend towards improving insulin sensitivity and ß-cell function as well as a reduced pancreatic iron load was observed following 6 months of iron chelation (TCTR20160523003).

Serum Levels of S100b and NSE Proteins in Patients with Non-Transfusion-Dependent Thalassemia as Biomarkers of Brain Ischemia and Cerebral Vasculopathy.

Patients with non-transfusion-dependent thalassemia (NTDT) are at risk of developing brain ischemia. Transcranial Doppler (TCD) has been established as a useful screening tool of cerebrovascular disease in patients with sickle cell disease. Proteins neuron specific enolase (NSE) and S100B are biomarkers that reflect CNS injury. The purpose of this study is to evaluate cerebral vessel vasculopathy and brain damage in NTDT patients using non-invasive methods as TCD and measurement serum levels of NSE and S100B. We included in our study 30 patients with NTDT, aged between 8 and 62 years old (mean: 29.4, median: 32) who presented in our Unit for regular follow-up. We performed in all patients a non-imaging TCD examination and have measured serum S100, NSE and lactate dehydrogenase (LDH) levels. We investigated the possible correlation between TCD results and S100B, NSE and LDH levels as well as between NSE-LDH and S100B-LDH levels by regression analysis. We found a statistically significant relationship for both NSE, S100B with LDH. We also found a statistically significant relationship for S100B and time-averaged mean velocity (TAMV)/peak velocity of left middle cerebral artery (MCA), NSE and pulsatility index (PI)/resistive index (RI) of the left posterior cerebral artery (PCA). TCD results correlated with biomarkers for brain ischemia. This finding enhances the role of TCD as a screening tool for brain ischemia in patients with NTDT.

Comparison between different software programs and post-processing techniques for the MRI quantification of liver iron concentration in thalassemia patients.

PURPOSE: In magnetic resonance imaging (MRI) relaxometry, various software programs are available to perform R2* measurements and to estimate the liver iron concentration (LIC). The main objective of our study was to compare R2* LIC values, obtained with three different software programs based on specific decay models and calibration curves, with LIC estimates provided by R2-relaxometry (FerriScan). METHODS: This retrospective study included 15 patients with 15 baseline MRIs and 34 serial examinations. R2* LIC estimates were calculated using the FuncTool, CMRtools/Thalassemia Tools and Quanta Hematology programs. Longitudinal LIC changes (ΔLIC) were calculated using the subset of 34 serial MRIs. RESULTS: After Bland-Altman analysis on baseline data, Quanta Hematology, which employs the monoexponential-plus-constant fit, produced the lowest mean difference [0.01 ± 0.14 log(mg/gdw)] with the closest limits of agreement. In the longitudinal setting, Quanta Hematology again gave the lowest mean difference between R2 and R2* LIC (0.1 ± 2.6 mg/gdw). Using FerriScan as reference, the value of concordant directional ΔLIC changes was the same for all programs (27/34, 85.7 %). CONCLUSIONS: R2* LICs are higher than R2 LICs at iron levels <7 mg/gdw, while R2 LIC averages higher than R2* LIC with increasing iron load. The monoexponential-plus-constant model provided the best agreement with R2 LIC estimates.

Management of pulmonary arterial hypertension associated to thalassemia: when pulmonary endarterectomy is the best therapeutical option? A case report.

Pulmonary arterial hypertension (PAH) has been reported with nearly all forms of the inherited as well as the acquired hemolytic anemias. Although screening studies suggested that PAH has emerged as major complication of thalassemia patients, its impact on survival is unknown; the pathophysiology of the PAH in these patients is multifactorial, and a thorough diagnostic evaluation is essential. Understanding the PAH pathogenesis, diagnostic options, prevention is critical for clinicians who care for the thalassemic patients; there are virtually no high-quality data on the safety/efficacy of PAH treatment strategy in this patient population. We are reporting the case of a thalassemic patient suffering from progressive severe PAH, not responding to medical treatment and related to chronic thromboembolic disease. After carefully considering all the options, we decided to proceed with vascular disobliteration by pulmonary endarterectomy (PEA), the first line choice in these cases. This intervention led to a significant improvement in the clinical status and in the functional parameters. Therefore, even if haemolytic anemia-associated-PAH is included in the group I of the Dana-point classification, an individualized approach is recommended as well as a particular management with disease-specific measures and a comprehensive evaluation of other causes of PAH; this current report supports the feasibility and effectiveness of PEA also in the thalassemic patients with surgically accessible chronic thromboembolic pulmonary hypertension.

Left ventricular torsional mechanics and myocardial iron load in beta-thalassaemia major: a potential role of titin degradation.

BACKGROUND: Iron may damage sarcomeric proteins through oxidative stress. We explored the left ventricular (LV) torsional mechanics in patients with beta-thalassaemia major and its relationship to myocardial iron load. Using HL-1 cell and B6D2F1 mouse models, we further determined the impact of iron load on proteolysis of the giant sarcomeric protein titin. METHODS AND RESULTS: In 44 thalassaemia patients aged 25 ± 7 years and 38 healthy subjects, LV torsion and twisting velocities were determined at rest using speckle tracking echocardiography. Changes in LV torsional parameters during submaximal exercise testing were further assessed in 32 patients and 17 controls. Compared with controls, patients had significantly reduced LV apical rotation, torsion, systolic twisting velocity, and diastolic untwisting velocity. T2* cardiac magnetic resonance findings correlated with resting diastolic untwisting velocity. The increments from baseline and resultant LV torsion and systolic and diastolic untwisting velocities during exercise were significantly lower in patients than controls. Significant correlations existed between LV systolic torsion and diastolic untwisting velocities in patients and controls, both at rest and during exercise. In HL-1 cells and ventricular myocardium of B6D2F1 mice overloaded with iron, the titin-stained pattern of sarcomeric structure became disrupted. Gel electrophoresis of iron-overloaded mouse myocardial tissue further showed significant decrease in the amount of titin isoforms and increase in titin degradation products. CONCLUSIONS: Resting and dynamic LV torsional mechanics is impaired in patients with beta-thalassaemia major. Cell and animal models suggest a potential role of titin degradation in iron overload-induced alteration of LV torsional mechanics.

Modified Magnetic Resonance Imaging Burden of Cerebral Small Vessel Disease and Related Risk Factors in Patients With Thalassemia.

OBJECTIVE: This study aimed to explore the burden of magnetic resonance imaging (MRI) of cerebral small vessel disease (CSVD) in patients with thalassemia and related risk factors. METHODS: The clinical data and MRI of patients with thalassemia were retrospectively analyzed, and non-thalassemia controls with matched sex and age were selected. The modified MRI burden of CSVD included recent small subcortical infarct, presumed vasogenic white matter hyperintensity, presumed vasogenic lacunae, perivascular space (PVS), and brain atrophy. RESULTS: This study included 110 patients in each of the thalassemia and control groups. There was no significant difference in sex, age, and common cerebrovascular disease risk factors between the 2 groups. The patients with thalassemia had a higher red blood cell count and lower content of hemoglobin. The PVS and modified MRI burden scores in the thalassemia group were higher than in the control group. With the increase in age, patients with thalassemia have a more severe CSVD burden. CONCLUSION: Patients with thalassemia have a heavier modified MRI burden of CSVD than non-thalassemia patients, particularly PVS, and aging is an important risk factor for CSVD changes.

Bone mineral density in adult thalassaemias: a retrospective longitudinal study.

OBJECTIVES: In this study, we aim to evaluate the long-term impact of thalassaemia on bone mineral density (BMD) through sequential analysis, compare changes in BMD values between male and female patients and find any correlation between BMD and biochemical markers in the adult thalassaemia group. BMD is a bone mineral density test using dual-energy X-ray to measure calcium hydroxyapatite per unit of bone, reflecting bone strength. METHODS: We conducted a longitudinal retrospective observational cohort study to determine the changes in BMD values and biochemical parameters in adult thalassaemia patients. BMD was assessed at the lumbar spine (L1-L4) and proximal femora using Hologic's bone dual-energy X-ray absorptiometry. Five serial BMD values were retrieved from electronic records. Biochemical parameters, including serum calcium, phosphorus and 25-hydroxyvitamin D levels, were also assessed. RESULTS: A total of 108 patients (47 males and 61 females; median age: 44 years) with thalassaemia major 71 patients, intermedia 20 patients, haemoglobin E disease 14 patients and thalassaemia-alpha three patients were included. The incidence of low BMD in patients with thalassaemia increased from 64 to 74% over three decades of analysis. Females and thalassaemia major patients had lower hip BMD values and corresponding Z -scores. CONCLUSION: There is a progressive decline in BMD values in adult thalassaemia, which was apparent in female thalassaemia major patients. No changes in biochemical parameters, however, were observed over long-term assessments.

Application of the magnetic resonance 3D multiecho Dixon sequence for quantifying hepatic iron overload and steatosis in patients with thalassemia.

OBJECTIVE: To investigate the feasibility and diagnostic efficacy of a 3D multiecho Dixon (qDixon) research application for simultaneously quantifying the liver iron concentration (LIC) and steatosis in thalassemia patients. MATERIALS AND METHODS: This prospective study enrolled participants with thalassemia who underwent 3 T MRI of the liver for the evaluation of hepatic iron overload. The imaging protocol including qDixon and conventional T2* mapping based on 2D multiecho gradient echo (ME GRE) sequences respectively. Regions of interest (ROIs) were drawn in the liver on the qDixon maps to obtain R2* and proton density fat fraction (PDFF). The reference R2* value was measured and calculated on conventional T2* mapping using the CMRtools software. Correlation analysis, Linear regression analysis, and Bland-Altman analysis were performed. RESULTS: 84 patients were finally included in this study. The median R2*-ME-GRE was 366.97 (1/s), range [206.68 (1/s), 522.20 (1/s)]. 8 patients had normal hepatic iron deposition, 16 had Insignificant, 42 had mild, 18 had moderate. The median of R2*-qDixon was 376.88 (1/s) [219.33 (1/s), 491.75 (1/s)]. A strong correlation was found between the liver R2*-qDixon and the R2*-ME-GRE (r = 0.959, P < 0.001). The median value of PDFF was 1.76% (1.10%, 2.95%). 8 patients had mild fatty liver, and 1 had severe fatty liver. CONCLUSION: MR qDixon research sequence can rapidly and accurately quantify liver iron overload, that highly consistent with the measured via conventional GRE sequence, and it can also simultaneously detect hepatic steatosis, this has great potential for clinical evaluation of thalassemia patients.

Risk factors and mortality associated with an elevated tricuspid regurgitant jet velocity measured by Doppler-echocardiography in thalassemia: a Thalassemia Clinical Research Network report.

An elevated tricuspid regurgitant jet velocity (TRV) is associated with hemolysis and early mortality in sickle cell disease, yet risk factors, clinical parameters, and mortality associated with this biomarker in thalassemia are poorly defined. This report summarizes the prevalence of an elevated TRV in 325 patients screened by Doppler echocardiography in the Thalassemia Clinical Research Network. A documented TRV was reported in 148 of 325 (46%) of patients. Average age was 25.9 years (range, 5-56 years) and 97% were transfusion-dependent. Mean TRV was 2.3 ± 0.4 m/s (range, 0.2-3.5 m/s). An abnormal TRV ≥ 2.5 m/s was identified in 49 of 148 (33%) of patients with a documented TRV, 5% (8/148), with a TRV ≥ 3.0 m/s, suggesting significant PH risk. Older age was strongly associated with a high TRV; however, 16% of children had a TRV ≥ 2.5 m/s. A history of splenectomy, hepatitis C, smoking, or high white blood cell count was associated with TRV elevation. In summary, an elevated TRV is noted in one-third of transfusion-dependent thalassemia patients with a documented value and develops in both children and adults. Age, splenectomy, hepatitis C, and smoking are significant univariate risk factors, with splenectomy surfacing as the dominant risk factor over time. Mortality was low in this cohort. Prospective longitudinal studies are needed. This study is registered at http://www.clinicaltrials.gov as NCT00661804.

Sildenafil therapy in thalassemia patients with Doppler-defined risk of pulmonary hypertension.

Pulmonary hypertension is a common but often overlooked complication associated with thalassemia syndromes. There are limited data on the safety and efficacy of selective pulmonary vasodilators in this at-risk population. We, therefore, designed a 12-week, open-label, phase 1/2, pilot-scale, proof-of-principle trial of sildenafil therapy in 10 patients with ß-thalassemia and at increased risk of pulmonary hypertension based on an elevated tricuspid regurgitant jet velocity >2.5 m/s on Doppler-echocardiography. Variables compared at baseline and after 12 weeks of sildenafil treatment included Doppler-echocardiographic parameters, 6-minute walked distance, Borg Dyspnea Score, New York Heart Association functional class, pulmonary function, and laboratory parameters. Treatment with sildenafil resulted in a significant decrease in tricuspid regurgitant jet velocity by 13.3% (3.0±0.7 versus 2.6±0.5 m/s, P=0.04), improved left ventricular end systolic/diastolic volume, and a trend towards a improved New York Heart Association functional class. No significant change in 6-minute walked distance was noted. Sildenafil was well tolerated, although minor expected adverse events were commonly reported. The total dose of sildenafil (mg) was strongly correlated with percent change in nitric oxide metabolite concentration in the plasma (ρ=0.80, P=0.01). There were also significant increases in plasma and erythrocyte arginine concentrations. Our study suggests that sildenafil is safe and may improve pulmonary hemodynamics in patients at risk of pulmonary hypertension; however, it was not demonstrated to improve the distance walked in 6 minutes. Clinical trials are needed to identify the best treatment strategy for pulmonary hypertension in patients with ß-thalassemia. (clinicaltrials.gov identifier: NCT00872170).