Evaluation of the efficacy of oral deferiprone in beta-thalassemia major by multislice multiecho T2*

What is the importance of monitoring iron levels in different organs over time with magnetic resonance imaging in transfusion-dependent thalassemia patients?

INTRODUCTION

Iron overload is the main pathophysiological driver of organ damage in transfusion-dependent thalassemia (TDT). Magnetic resonance imaging (MRI) provides detailed insights into the distribution and severity of iron accumulation in the different organs.

AREAS COVERED

This special report describes the impact of MRI on clinical and therapeutic management and short- and long-term outcomes in TDT patients. PubMed, Scopus, and Google Scholar databases were searched to identify the relevant studies published before November 2024.

EXPERT OPINION

Cardiac and hepatic MRI are now well-established modalities, integrated into the clinical practice. They have become essential for tailoring iron chelation therapies to the specific patient's needs and for monitoring treatment efficacy. The improved control of cardiac iron burden has translated into reduced morbidity and mortality. The MRI accessibility remains limited in resource-limited settings and progress in this field relies on educating and training centers to ensure accurate execution and interpretation. The clinicopathological significance, prognostic value, and reproducibility of pancreatic iron levels assessment have been established, charting a path toward its clinical use. There are limited data about renal, adrenal, and pituitary iron deposition, and more research is needed to fully establish the functional significance and to standardize and validate the MRI protocols.

Iron overload: The achilles heel of β-thalassemia

Systematic transfusions coupled with iron chelation therapy have substantially improved the life expectancy of thalassemia patients in developed nations. As the human organism does not have a protective mechanism to remove excess iron, iron overload is a significant concern in thalassemia, leading to organ damage, especially in the heart and liver. Thus, iron chelation therapy is crucial to prevent or reverse organ iron overload. There are three widely used iron chelators, either as monotherapy or in combination. The choice of iron chelator depends on several factors, including local guidelines, drug availability, and the individual clinical scenario. Despite treatment advancements, challenges persist, especially in resource-limited settings, highlighting the need for improved global healthcare access. This review discusses clinical management, current treatments, and future directions for thalassemia, focusing on iron overload and its complications. Furthermore, it underscores the progress in transforming thalassemia into a manageable chronic condition and the potential of novel therapies to further enhance patient outcomes.

Imaging in Heart Failure with Preserved Ejection Fraction: A Multimodality Imaging Point of View

Heart failure with preserved ejection fraction (HFpEF) is an important global health problem. Despite increased prevalence due to improved diagnostic options, limited improvement has been achieved in cardiac outcomes. HFpEF is an extremely complex syndrome and multimodality imaging is important for diagnosis, identifying its different phenotypes and determining prognosis. Evaluation of left ventricular filling pressures using echocardiographic diastolic function parameters is the first step of imaging in clinical practice. The role of echocardiography is becoming more popular and with the recent developments in deformation imaging, cardiac MRI is extremely important as it can provide tissue characterisation, identify fibrosis and optimal volume measurements of cardiac chambers. Nuclear imaging methods can also be used in the diagnosis of specific diseases, such as cardiac amyloidosis.

Multi-Parametric Cardiac Magnetic Resonance for Prediction of Heart Failure Death in Thalassemia Major

We assessed the prognostic value of multiparametric cardiovascular magnetic resonance (CMR) in predicting death from heart failure (HF) in thalassemia major (TM). We considered 1398 white TM patients (30.8 ± 8.9 years, 725 women) without a history of HF at baseline CMR, which was performed within the Myocardial Iron Overload in Thalassemia (MIOT) network. Iron overload was quantified by using the T2* technique, and biventricular function was determined with cine images. Late gadolinium enhancement (LGE) images were acquired to detect replacement myocardial fibrosis. During a mean follow-up of 4.83 ± 2.05 years, 49.1% of the patients changed the chelation regimen at least once; these patients were more likely to have significant myocardial iron overload (MIO) than patients who maintained the same regimen. Twelve (1.0%) patients died from HF. Significant MIO, ventricular dysfunction, ventricular dilation, and replacement myocardial fibrosis were identified as significant univariate prognosticators. Based on the presence of the four CMR predictors of HF death, patients were divided into three subgroups. Patients having all four markers had a significantly higher risk of dying for HF than patients without markers (hazard ratio (HR) = 89.93; 95%CI = 5.62-1439.46; p = 0.001) or with one to three CMR markers (HR = 12.69; 95%CI = 1.60-100.36; p = 0.016). Our findings promote the exploitation of the multiparametric potential of CMR, including LGE, for better risk stratification for TM patients.

Iron chelation alleviates multiple pathophysiological pathways in a rat model of cardiac pressure overload

Iron dysmetabolism affects a great proportion of heart failure patients, while chronic hypertension is one of the most common risk factors for heart failure and death in industrialized countries. Serum data from reduced ejection fraction heart failure patients show a relative or absolute iron deficiency, whereas cellular myocardial analyses field equivocal data. An observed increase in organellar iron deposits was incriminated to cause reactive oxygen species formation, lipid peroxidation, and cell death. Therefore, we studied the effects of iron chelation on a rat model of cardiac hypertrophy. Suprarenal abdominal aortic constriction was achieved surgically, with a period of nine weeks to accommodate the development of chronic pressure overload. Next, deferiprone (100 mg/kg/day), a lipid-permeable iron chelator, was administered for two weeks. Pressure overload resulted in increased inflammation, fibrotic remodeling, lipid peroxidation, left ventricular hypertrophy and mitochondrial iron derangements. Deferiprone reduced cardiac inflammation, lipid peroxidation, mitochondrial iron levels, and hypertrophy, without affecting circulating iron levels or ejection fraction. In conclusion, metallic molecules may pose ambivalent effects within the cardiovascular system, with beneficial effects of iron redistribution, chiefly in the mitochondria.

An evaluation of deferiprone as twice-a-day tablets or in combination therapy for the treatment of transfusional iron overload in thalassemia syndromes

INTRODUCTION

Regular blood transfusions in patients with thalassemia syndromes can cause iron overload resulting in complications including cirrhosis, heart problems, or endocrine abnormalities. To prevent iron overload toxicity in these patients, three iron chelators are currently FDA-approved for use: deferoxamine, deferasirox, and deferiprone. In the United States, deferiprone has been approved for three times daily dosing since 2011 and has recently gained approval for twice-daily administration.

AREAS COVERED

A PubMed literature search was performed with the keywords 'deferiprone' and 'thalassemia.' Relevant original research studying deferiprone's effects on transfusional iron overload in patients with thalassemia syndromes was included. Exclusion criteria included case reports and review papers. Deferiprone is effective at reducing serum ferritin levels in patients with iron overload. Twice-daily administration provides a similar level of iron chelation as three times daily dosing with a comparable side effect profile and increased patient acceptability.

EXPERT OPINION

New studies are highlighting deferiprone's potential for combination therapy with either deferoxamine or deferasirox to improve iron chelation. Deferiprone's ability to significantly decrease cardiac and liver iron content can be utilized in other transfusion-dependent hematologic conditions, as evidenced by its recent approval for use in the United States for sickle cell disease or other anemias.

Increased myocardial extracellular volume is associated with myocardial iron overload and heart failure in thalassemia major

OBJECTIVES

Myocardial extracellular volume (ECV) by cardiovascular magnetic resonance (CMR) is a surrogate marker of diffuse fibrosis. We evaluated the association between ECV and demographics, CMR findings, and cardiac involvement in patients with thalassemia major (TM).

METHODS

A total of 108 β-TM patients (62 females, 40.16 ± 8.83 years), consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network, and 16 healthy subjects (6 females, 37.12 ± 16.13 years) underwent CMR. The protocol included assessment of T2*, native T1, and T2 values in all 16 myocardial segments for myocardial iron overload (MIO) quantification, cine images for left ventricular (LV) function quantification, post-contrast T1 mapping for ECV calculation, and late gadolinium enhancement (LGE) technique for replacement myocardial fibrosis detection.

RESULTS

Global ECV values were significantly higher in females than in males. Global ECV values were significantly higher in patients with significant MIO (global heart T2* < 20 ms) than in patients without significant MIO, and both groups exhibited higher global ECV values than healthy subjects. No association was detected between native T1 and ECV values, while patients with reduced global heart T2 values showed significantly higher global ECV values than patients with normal and increased global heart T2. Global ECV values were not correlated with LV function/size and were comparable between patients with and without LGE. Compared to patients without heart failure, patients with a history of heart failure (N = 10) showed significantly higher global heart ECV values.

CONCLUSION

In TM, increased myocardial ECV, potentially reflecting diffuse interstitial fibrosis, is associated with MIO and heart failure.

KEY POINTS

• CMR-derived myocardial extracellular volume is increased in thalassemia major patients, irrespective of the presence of late gadolinium enhancement. • In thalassemia major, myocardial iron overload contributes to the increase in myocardial ECV, which potentially reflects diffuse interstitial fibrosis and is significantly associated with a history of heart failure.

Deep Learning Staging of Liver Iron Content From Multiecho MR Images

BACKGROUND

MRI represents the most established liver iron content (LIC) evaluation approach by estimation of liver T2* value, but it is dependent on the choice of the measurement region and the software used for image analysis.

PURPOSE

To develop a deep-learning method for unsupervised classification of LIC from magnitude T2* multiecho MR images.

STUDY TYPE

Retrospective.

POPULATION/SUBJECTS

A total of 1069 thalassemia major patients enrolled in the core laboratory of the Myocardial Iron Overload in Thalassemia (MIOT) network, which were included in the training (80%) and test (20%) sets. Twenty patients from different MRI vendors included in the external test set.

FIELD STRENGTH/SEQUENCE

A5 T, T2* multiecho magnitude images.

ASSESSMENT

Four deep-learning convolutional neural networks (HippoNet-2D, HippoNet-3D, HippoNet-LSTM, and an ensemble network HippoNet-Ensemble) were used to achieve unsupervised staging of LIC using five classes (normal, borderline, middle, moderate, severe). The training set was employed to construct the deep-learning model. The performance of the LIC staging model was evaluated in the test set and in the external test set. The model's performances were assessed by evaluating the accuracy, sensitivity, and specificity with respect to the ground truth labels obtained by T2* measurements and by comparison with operator-induced variability originating from different region of interest (ROI) placements.

STATISTICAL TESTS

The network's performances were evaluated by single-class accuracy, specificity, and sensitivity and compared by one-way repeated measures analysis of variance (ANOVA) and one-way ANOVA.

RESULTS

HippoNet-Ensemble reached an accuracy significantly higher than the other networks, and a sensitivity and specificity higher than HippoNet-LSTM. Accuracy, sensitivity, and specificity values for the LIC stages were: normal: 0.96/0.93/0.97, borderline: 0.95/0.85/0.98, mild: 0.96/0.88/0.98, moderate: 0.95/0.89/0.97, severe: 0.97/0.95/0.98. Correctly staging of cases was in the range of 85%-95%, depending on the LIC class. Multiclass accuracy was 0.90 against 0.92 for the interobserver variability.

DATA CONCLUSION

The proposed HippoNet-Ensemble network can perform unsupervised LIC staging and achieves good prognostic performance.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

Left ventricular global function index is associated with myocardial iron overload and heart failure in thalassemia major patients

PURPOSE

The left ventricular global function index (LVGFI) is a comprehensive marker of cardiac performance, integrating LV morphology with global function. We explored the cross-sectional association of LVGFI with myocardial iron overload (MIO), LV ejection fraction (LVEF), myocardial fibrosis, and heart failure (HF) in β-thalassemia major (TM) patients.

METHODS

We considered 1352 adult TM patients (708 females, 32.79 ± 7.16years) enrolled in the Myocardial Iron Overload in Thalassemia Network and 112 healthy subjects (50 females, 32.09 ± 6.08years). LVGFI and LVEF were assessed by cine images and MIO by multislice multiecho T2* technique. Replacement myocardial fibrosis was detected by late gadolinium enhancement technique.

RESULTS

LVGFI and LVEF were significantly lower in patients with significant MIO (global heart T2*<20ms) than in patients without MIO and in healthy subjects but were comparable between TM patients without MIO and healthy subjects. In TM, LVGFI was significantly associated with LVEF (R = 0.733; p < 0.0001). Global heart T2* values were significantly associated with both LVGFI and LVEF, but the correlation with LVGFI was significantly stronger (p = 0.0001). Male sex, diabetes mellitus, significant MIO, and replacement myocardial fibrosis were the strongest predictors of LVGFI. Eighty-six patients had a history of HF and showed significantly lower global heart T2* values, LVEF, and LVGFI than HF-free patients. A LVGFI ≤ 44.9% predicted the presence of HF. The LVGFI showed a diagnostic performance superior to that of LVEF (area under the curve: 0.67 vs. 0.62; p = 0.039).

CONCLUSION

In TM patients the LVGFI correlates with MIO and provides incremental diagnostic value for HF detection compared with LVEF.

Gender Differences in Knowledge and Perception of Cardiovascular Disease among Italian Thalassemia Major Patients

We evaluated gender differences in knowledge and perception of cardiovascular disease (CVD) among Italian thalassemia major (TM) patients. An anonymous questionnaire was completed by 139 β-TM patients (87 (62.7%) females, 40.90 ± 8.03 years). Compared to females, males showed a significantly higher frequency of CVDs, and they less frequently selected tumors in general as the greatest health problem for people of the same age and gender (48.1% vs. 66.7%; p = 0.031) and as the greatest danger to their future health (26.9% vs. 43.7%; p = 0.048). CVDs were designated as the greatest danger to their future health by a significantly higher percentage of males than females (53.8% vs. 36.8%; p = 0.048). Both males and females showed a good knowledge of cardiovascular risk factors and preventive measures for CVDs. No gender differences were detected in the subjective well-being and the perceived cardiovascular risk. The perceived risk was not influenced by age, presence of cardiovascular risk factors, or disease, but no patient with a low perceived CVD risk had myocardial iron overload. Our findings highlight the need to implement future educational programs aimed at increasing the awareness of CVD as the greatest health issue, especially among the female TM population, and at informing TM patients of the different actors, besides iron, that play a role in the development of cardiovascular complications.

The Importance of Functional and Feature-Tracking Cardiac MRI Parameters in Prediction of Adverse Cardiac Events and Cardiac Mortality in Thalassemia Patients

RATIONALE AND OBJECTIVES

Despite some investigations about the role of cardiovascular magnetic resonance (CMR) imaging in thalassemia, there are a few studies regarding the feature-tracking (FT). We evaluated the role of T2*, functional, and FT values for the determining of adverse cardiac events (ACE).

METHODS

One-hundred-fifty-nine patients with thalassemia-major (49.7% female, mean-age = 32 ± 9.8 year) were followed for 8 - 64 (median = 36) months. CMR derived functional, FT, and T2* as well as ACE (heart failure hospitalization, cardiac mortality, pulmonary hypertension, and arrhythmias) were recorded. Also, variables were analyzed for cardiac death prediction separately.

RESULTS

Seventeen patients (10.7%) developed ACE. The right-ventricular ejection fraction (RVEF) was the strongest indicator of ACE (OR: 0.85, 95% - CI: 0.790 - 0.918; p < 0.001) and cardiac mortality (OR: 0.88, 95%-CI: 0.811 - 0.973; p = 0.01). RVEF ≤ 39% and ≤ 37% predicted ACE and mortality with sensitivity of 62.5% and 71.43% and specificity of 95.77% and 93.38%, respectively. Additionally, myocardial-T2* was a predictor of mortality (OR: 0.90, 95%-CI: 0.814 - 0.999; p = 0.04). T2* ≤ 10 months predicted death with 85.71% sensitivity and 85.91% specificity. RV global longitudinal strain (GLS) was the strongest strain parameter for the indication of ACE and death (OR: 0.81, 95%-CI: 0.740 - 0.902; p < 0.001 and OR: 0.81, 95%- CI: 0.719 - 0.933; p = 0.003, respectively). RV GLS ≤ 16.43% and ≤ 15.63% determined ACE and death with sensitivity of 52.94% and 71.43% and specificity of 90%, respectively.

CONCLUSION

Our results underscore the role of FT and non-contrast CMR parameters as valuable markers of ACE in thalassemia.

MRI-Based Iron Phenotyping and Patient Selection for Next-Generation Sequencing of Non-Homeostatic Iron Regulator Hemochromatosis Genes

BACKGROUND AND AIMS

High serum ferritin is frequent among patients with chronic liver disease and commonly associated with hepatic iron overload. Genetic causes of high liver iron include homozygosity for the p.Cys282Tyr variant in homeostatic iron regulator (HFE) and rare variants in non-HFE genes. The aims of the present study were to describe the landscape and frequency of mutations in hemochromatosis genes and determine whether patient selection by noninvasive hepatic iron quantification using MRI improves the diagnostic yield of next-generation sequencing (NGS) in patients with hyperferritinemia.

APPROACH AND RESULTS

A cohort of 410 unselected liver clinic patients with high serum ferritin (defined as ≥200 μg/L for women and ≥300 μg/L for men) was investigated by HFE genotyping and abdominal MRI R2*. Forty-one (10%) patients were homozygous for the p.Cys282Tyr variant in HFE. Of the remaining 369 patients, 256 (69%) had high transferrin saturation (TSAT; ≥45%) and 199 (53%) had confirmed hepatic iron overload (liver R2* ≥70 s^-1 ). NGS of hemochromatosis genes was carried out in 180 patients with hepatic iron overload, and likely pathogenic variants were identified in 68 of 180 (38%) patients, mainly in HFE (79%), ceruloplasmin (25%), and transferrin receptor 2 (19%). Low spleen iron (R2* <50 s^-1 ), but not TSAT, was significantly associated with the presence of mutations. In 167 patients (93%), no monogenic cause of hepatic iron overload could be identified.

CONCLUSIONS

In patients without homozygosity for p.Cys282Tyr, coincident pathogenic variants in HFE and non-HFE genes could explain hyperferritinemia with hepatic iron overload in a subset of patients. Unlike HFE hemochromatosis, this type of polygenic hepatic iron overload presents with variable TSAT. High ferritin in blood is an indicator of the iron storage disease, hemochromatosis. A simple genetic test establishes this diagnosis in the majority of patients affected. MRI of the abdomen can guide further genetic testing.

The predictive role of cardiac magnetic resonance imaging in determining thalassemia patients with intermediately to highly probable pulmonary hypertension

OBJECTIVES

We sought to determine the cardiac magnetic resonance (CMR) indicators of intermediately to highly probable pulmonary hypertension (IHpPH) in patients with thalassemia referred for myocardial iron overload assessments to prevent further cardiac complications.

METHODS

The study population consisted of 152 patients with thalassemia (major or intermedia) (49.3% women, mean age = 33 ± 10.1 years) who underwent non-contrast CMR and echocardiographic examinations on the same day. Functional, T2*, and global strain parameters via a feature-tracking method were extracted from CMR. The probability of PH was defined based on the tricuspid regurgitation velocity and echocardiographic parameters. The catheterization-derived hemodynamic data of patients with moderate to high probable PH was registered.

RESULTS

Twenty-two (14.5%) patients suffered from IHpPH. The multivariate logistic regression analysis revealed that the right ventricular end-systolic volume index (RVESVI) was the strongest of all the CMR parameters for the prediction of IHpPH (OR: 1.044, 95% CI: 1.021-1.067). The other powerful IHpPH predictor was age (OR: 1.066, 95% CI: 1.009-1.126). A cutoff point of greater than 47 ml for RVESVI (AUC: .801, 95% CI: .728-.861) was found to predict IHpPH with 73.91% sensitivity and 70.31% specificity. The single most robust CMR-derived strain parameter for IHpPH prediction was the right ventricular global longitudinal strain (OR: .887, 95% CI: .818-.961). A p value of less than 0.05 was considered significant.

CONCLUSIONS

Both CMR functional and global strain parameters were strong predictors of IHpPH in our patients with thalassemia.

Myocardial iron overload by cardiovascular magnetic resonance native segmental T1 mapping: a sensitive approach that correlates with cardiac complications

BACKGROUND

We compared cardiovascular magnetic resonance segmental native T1 against T2* values for the detection of myocardial iron overload (MIO) in thalassaemia major and we evaluated the clinical correlates of native T1 measurements.

METHODS

We considered 146 patients (87 females, 38.7 ± 11.1 years) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassaemia Network. T1 and T2* values were obtained in the 16 left ventricular (LV) segments. LV function parameters were quantified by cine images. Post-contrast late gadolinium enhancement (LGE) and T1 images were acquired.

RESULTS

64.1% of segments had normal T2* and T1 values while 10.1% had pathologic T2* and T1 values. In 526 (23.0%) segments, there was a pathologic T1 and a normal T2* value while 65 (2.8%) segments had a pathologic T2* value but a normal T1 and an extracellular volume (ECV) ≥ 25% was detected in 16 of 19 segments where ECV was quantified. Global native T1 was independent from gender or LV function but decreased with increasing age. Patients with replacement myocardial fibrosis had significantly lower native global T1. Patients with cardiac complications had significantly lower native global T1.

CONCLUSIONS

The combined use of both segmental native T1 and T2* values could improve the sensitivity for detecting MIO. Native T1 is associated with cardiac complications in thalassaemia major.

Prospective cardiac magnetic resonance imaging survey in myelodysplastic syndrome patients: insights from an Italian network

We prospectively evaluated changes in cardiac and hepatic iron overload (IO) and in morpho-functional cardiac parameters and myocardial fibrosis by magnetic resonance imaging (MRI) in patients with low-risk and intermediate-1-risk myelodysplastic syndromes (MDS). Fifty patients enrolled in the Myocardial Iron Overload in MyElodysplastic Diseases (MIOMED) study were followed for 12 months. IO was quantified by the T2* technique and biventricular function parameters by cine images. Macroscopic myocardial fibrosis was detected by late gadolinium enhancement technique. Twenty-eight patients (71.89±8.46 years; 8 females) performed baseline and follow-up MRIs. Thirteen patients had baseline hepatic IO, with a higher frequency among transfusion-dependent patients. Out of the 15 patients with a baseline MRI liver iron concentration <3 mg/g/dw, two (non-chelated) developed hepatic IO. Thirteen (46.4%) patients had an abnormal T2* value in at least one myocardial segment. One patient without hepatic IO and non-transfused had baseline global T2* <20 ms. Among the 15 patients with no baseline myocardial IO (MIO), 2 worsened. There was a significant increase in both left and right ventricular end-diastolic volume indexes. Thirty-six percent of patients showed myocardial fibrosis correlating with aging. Two new occurrences were detected at the follow-up. In conclusion, by a more sensitive segmental approach, MIO is quite frequent in MDS patients and it can be present also in non-transfused patients and in absence of detectable hepatic iron. The incidence of cardiac and hepatic IO and of myocardial fibrosis and the increase in biventricular volumes after a 12-month interval suggest performing periodic MRI scans to better manage MDS patients.

Role of CMR feature-tracking derived left ventricular strain in predicting myocardial iron overload and assessing myocardial contractile dysfunction in patients with thalassemia major

OBJECTIVE

Myocardial iron overload (MIO) in thalassemia major (TM) may cause subclinical left ventricular (LV) dysfunction which manifests with abnormal strain parameters before a decrease in ejection fraction (EF). Early detection of MIO using cardiovascular magnetic resonance (CMR)-T2* is vital. Our aim was to assess if CMR feature-tracking (FT) strain correlates with T2*, and whether it can identify early contractile dysfunction in patients with MIO but normal EF.

METHODS

One hundred and four consecutive TM patients with LVEF > 55% on echocardiography were prospectively enrolled. Those fulfilling the inclusion criteria underwent CMR, with T2* being the gold standard for detecting MIO. Group 1 included patients without significant MIO (T2* > 20 ms) and group 2 with significant MIO (T2* < 20 ms).

RESULTS

Eighty-six patients (mean age, 17.32 years, 59 males) underwent CMR. There were 68 (79.1%) patients in group 1 and 18 (20.9%) in group 2. Fourteen patients (16.3%) had mild-moderate MIO, and four (4.6%) had severe MIO. Patients in group 2 had significantly lower global radial strain (GRS). Global longitudinal strain (GLS) and global circumferential strain (GCS) did not correlate with T2*. T1 mapping values were significantly lower in patients with T2* < 10 ms than those with T2* of 10-20 ms; however, FT-strain values were not significantly different between these two groups.

CONCLUSION

CMR-derived GRS, but not GLS and GCS, correlated with CMR T2*. GRS is significantly decreased in TM patients with MIO and normal EF when compared with those without. FT-strain may be a useful adjunct to CMR T2* and maybe an early marker of myocardial dysfunction in TM.

KEY POINTS

• A global radial strain of < 29.3 derived from cardiac MRI could predict significant myocardial iron overload in patients with thalassemia, with a sensitivity of 76.5% and specificity of 66.7%. • Patients with any myocardial iron overload have significantly lower GRS, compared to those without, suggesting the ability of CMR strain to identify subtle myocardial contractile disturbances. • T1 and T2 mapping values are significantly lower in those with severe myocardial iron than those with mild-moderate iron, suggesting a potential role of T1 and T2 mapping in grading myocardial iron.

Reduced iron export associated with hepcidin resistance can explain the iron overload spectrum in ferroportin disease

BACKGROUND & AIMS

Ferroportin disease (FD) and hemochromatosis type 4 (HH4) are associated with variants in the ferroportin-encoding gene SLC40A1. Both phenotypes are characterized by iron overload despite being caused by distinct variants that either mediate reduced cellular iron export in FD or resistance against hepcidin-induced inactivation of ferroportin in HH4. The aim of this study was to assess if reduced iron export also confers hepcidin resistance and causes iron overload in FD associated with the R178Q variant.

METHODS

The ferroportin disease variants R178Q andA77D and the HH4-variant C326Y were overexpressed in HEK-293T cells and subcellular localization was characterized by confocal microscopy and flow cytometry. Iron export and cytosolic ferritin were measured as markers of iron transport and radioligand binding studies were performed. The hepcidin-ferroportin axis was assessed by ferritin/hepcidin correlation in patients with different iron storage diseases.

RESULTS

In the absence of hepcidin, the R178Q and A77D variants exported less iron when compared to normal and C326Y ferroportin. In the presence of hepcidin, the R178Q and C326Y, but not the A77D-variant, exported more iron than cells expressing normal ferroportin. Regression analysis of serum hepcidin and ferritin in patients with iron overload are compatible with hepcidin deficiency in HFE hemochromatosis and hepcidin resistance in R178Q FD.

CONCLUSIONS

These results support a novel concept that in certain FD variants reduced iron export and hepcidin resistance could be interlinked. Evasion of mutant ferroportin from hepcidin-mediated regulation could result in uncontrolled iron absorption and iron overload despite reduced transport function.

Influence of mitochondrial and systemic iron levels in heart failure pathology

Iron deficiency or overload poses an increasingly complex issue in cardiovascular disease, especially heart failure. The potential benefits and side effects of iron supplementation are still a matter of concern, even though current guidelines suggest therapeutic management of iron deficiency. In this review, we sought to examine the iron metabolism and to identify the rationale behind iron supplementation and iron chelation. Cardiovascular disease is increasingly linked with iron dysmetabolism, with an increased proportion of heart failure patients being affected by decreased plasma iron levels and in turn, by the decreased quality of life. Multiple studies have concluded on a benefit of iron administration, even if just for symptomatic relief. However, new studies field evidence for negative effects of dysregulated non-bound iron and its reactive oxygen species production, with concern to heart diseases. The molecular targets of iron usage, such as the mitochondria, are prone to deleterious effects of the polyvalent metal, added by the scarcely described processes of iron elimination. Iron supplementation and iron chelation show promise of therapeutic benefit in heart failure, with the extent and mechanisms of both prospects not being entirely understood. It may be that a state of decreased systemic and increased mitochondrial iron levels proves to be a useful frame for future advancements in understanding the interconnection of heart failure and iron metabolism.

Treatment margins in radiotherapy for liver tumors visualized as T2*-hypointense areas on SPIO-enhanced MRI at 9.4 T

OBJECTIVE

To investigate whether a SPIO-labeling technique could enable MR visualization of the treatment margin after X-irradiation at a single dose of 30 Gy.

MATERIALS AND METHODS

Fifteen rats bearing N1-S1 hepatoma in either the left (group 1) or right (group 2) liver lobe were examined. Four hours after systemic SPIO administration, the left lobe was selectively irradiated at 30 Gy. Liver T2* maps were acquired 7 days later using a 9.4 T scanner. The livers were excised and examined histologically.

RESULTS

The irradiated area showed T2*-weighted hypointensity with significantly shorter T2* values than those in the non-irradiated area (p < 0.001). Tumors in group 1 completely disappeared, whereas tumors in group 2 had grown outside the T2*-weighted hypointensity by up to ~ 2.3 times that at baseline. Group 1 showed significantly higher probability of tumor regression than group 2 (p = 0.048). Histologically, iron deposition was heavier in irradiated areas than in non-irradiated areas.

DISCUSSION

Even at a single dose of 30 Gy, which is a slightly higher dose than can be used clinically in stereotactic body radiotherapy, MR visualization of the treatment margin was achieved, because tumors showed significant growth outside the T2*-hypointense areas. In contrast, tumors disappeared inside the T2*-hypointense areas.

CMR for myocardial iron overload quantification: calibration curve from the MIOT Network

OBJECTIVES

R2* cardiac magnetic resonance (CMR) allows the non-invasive measurement of myocardial iron. We calibrated cardiac R2* values against myocardial tissue-measured iron concentration by using a segmental approach and we assessed the iron distribution.

METHODS

Five hearts of thalassemia patients were donated after death/transplantation to the CoreLab of the Myocardial Iron Overload in Thalassemia Network. A multislice multiecho R2* approach was adopted. After CMR, used as guidance, the heart was cut in three short-axis slices and each slice was cut into different equiangular segments according to AHA segmentation and differentiated into endocardial and epicardial layers. Tissue iron concentration was measured by atomic absorption spectrometer technique.

RESULTS

Fifty-five samples were used since only for two hearts all the 16 samples were analyzed. Mean iron concentration was 4.71 ± 4.67 mg/g dw. Segmental iron levels ranged from 0.24 to 13.78 mg/g dw. The coefficient of variability of iron for myocardial segments ranged from 8.08 to 24.54% (mean 13.49 ± 6.93%). Iron concentration was significantly higher in the epicardial than in the endocardial layer (5.99 ± 6.01 vs 4.84 ± 4.87 mg/g dw; p = 0.042). Four different circumferential regions (anterior, septal, inferior, and lateral) were defined. A circumferential heterogeneity was noted, with more iron in the anterior region, followed by the inferior region. The direct nonlinear fitting of R2* and [Fe] data led to the calibration curve: [Fe] = 0.0022 ∙ (R2*-ROI)^1.462 (R-square = 0.956).

CONCLUSIONS

Our data further validate R2* CMR using a segmental approach as a sensitive and early technique for quantifying iron distribution in the current clinical practice.

KEY POINTS

• Calibration in humans for cardiovascular magnetic resonance R2* against myocardial iron concentration was provided. • A circumferential heterogeneity in cardiac iron distribution was detected: more iron was observed in the anterior region, followed by the inferior region. This finding corroborates the use of a segmental T2* CMR approach in the clinical practice to detect a heterogeneous iron distribution. • The comparison between the cardiac T2* values obtained with the region-based and the pixel-wise approaches showed a significant correlation and no significant difference but, in presence of significant iron load, the region-based approach resulted in significantly higher T2* values.

Cardiac T2 * mapping: Techniques and clinical applications

Cardiac T₂* mapping is a noninvasive MRI method that is used to identify myocardial iron accumulation in several iron storage diseases such as hereditary hemochromatosis, sickle cell disease, and β‐thalassemia major. The method has improved over the years in terms of MR acquisition, focus on relative artifact‐free myocardium regions, and T₂* quantification. Several improvement factors involved include blood pool signal suppression, the reproducibility of T₂* measurement as affected by scanner hardware, and acquisition software. Regarding the T₂* quantification, improvement factors include the applied curve‐fitting method with or without truncation of the signals acquired at longer echo times and whether or not T₂* measurement focuses on multiple segmental regions or the midventricular septum only. Although already widely applied in clinical practice, data processing still differs between centers, contributing to measurement outcome variations. State of the art T₂* measurement involves pixelwise quantification providing better spatial iron loading information than region of interest‐based quantification. Improvements have been proposed, such as on MR acquisition for free‐breathing mapping, the generation of fast mapping, noise reduction, automatic myocardial contour delineation, and different T₂* quantification methods. This review deals with the pro and cons of different methods used to quantify T₂* and generate T₂* maps. The purpose is to recommend a combination of MR acquisition and T₂* mapping quantification techniques for reliable outcomes in measuring and follow‐up of myocardial iron overload. The clinical application of cardiac T₂* mapping for iron overload's early detection, monitoring, and treatment is addressed. The prospects of T₂* mapping combined with different MR acquisition methods, such as cardiac T₁ mapping, are also described.

Level of Evidence: 4

Technical Efficacy Stage: 5

J. Magn. Reson. Imaging 2019.

Cardiac involvement by CMR in different genotypic groups of thalassemia major patients

Beta thalassemia major (β-TM) displays a great deal of phenotypic heterogeneity, not fully investigated in terms of cause-effect. We aimed to detect if different genotypic groups could be related to different levels of cardiac impairment, evaluated by cardiovascular magnetic resonance (CMR). We considered 671 β-TM patients (age 30.1 years, 52.9% females) consecutively enrolled in the Myocardial Iron Overload (MIO) in Thalassemia network. MIO was assessed by T2* technique. Biventricular function was quantified by cine images. Myocardial fibrosis was evaluated by late gadolinium enhancement (LGE) technique. Three groups of patients were identified: heterozygotes β⁺/β° (N = 279), homozygotes β ⁺ (N = 154), homozygotes β° (N = 238). Transfusional needs resulted significantly lower in homozygous β ⁺ TM patients when compared to the other groups. The homozygous β ⁺ group versus the heterozygous and homozygous β° groups showed higher global heart T2* values (P < 0.0001) and a lower number of patients with a global heart T2* value<20 ms (P < 0.001). The homozygotes β ⁺ showed a lower number of patients with a pathological left ventricular ejection fraction (LVEF) than the other two groups (P < 0.05). The β⁺/β ⁺ TM patients showed less MIO and a concordant better systolic heart function. These data support the knowledge of different genotypic groups in the management of β-TM patients.

MRI multicentre prospective survey in thalassaemia major patients treated with deferasirox versus deferiprone and desferrioxamine

We prospectively assessed the efficacy of deferasirox versus deferiprone or desferrioxamine as monotherapy in thalassaemia major (TM) patients by magnetic resonance imaging (MRI). We selected the patients enrolled in the Myocardial Iron Overload in Thalassaemia network who received only one chelator between two MRIs (deferasirox = 235, deferiprone = 142, desferrioxamine = 162). Iron overload was measured by T2* technique and biventricular function by cine images. Among the patients with baseline myocardial iron, in all three groups there was a significant improvement in global heart T2* values. The deferiprone and desferrioxamine groups showed a significant improvement in left ventricular ejection fraction (LVEF). Only the deferiprone group showed a significant improvement in right ventricular ejection fraction (RVEF). The improvement in global heart T2* was significantly lower in the deferasirox versus the deferiprone group. The improvement in the LVEF was significantly higher in the deferiprone and desferrioxamine groups than in the deferasirox group and the improvement in the RVEF was significantly higher in the deferiprone than in deferasirox group. Among the patients with baseline hepatic iron, the changes in hepatic iron were comparable in deferasirox versus the other groups. Deferasirox monotherapy was less effective than deferiprone in improving myocardial siderosis and biventricular function and less effective than desferrioxamine in improving the LVEF.

Multicenter validation of the magnetic resonance T2* technique for quantification of pancreatic iron

OBJECTIVES

To assess the transferability of the magnetic resonance imaging (MRI) multislice multiecho T2* technique for pancreatic iron overload assessment.

METHODS

Multiecho T2* sequences were installed on ten 1.5-T MRI scanners of the three main vendors. Five healthy subjects (n = 50) were scanned at each site. Five patients with thalassemia (n = 45) were scanned locally at each site and were rescanned at the reference site within 1 month. T2* images were analyzed using a previously validated software and the global pancreatic T2* value was calculated as the mean of T2* values over the head, body, and tail.

RESULTS

T2* values of healthy subjects were above 26 ms and showed inter-site homogeneity. The T2* values measured in the MRI sites were comparable to the correspondent values observed in the reference site (12.02 ± 10.20 ms vs 11.98 ± 10.47 ms; p = 0.808), and the correlation coefficient was 0.978 (p < 0.0001). Coefficients of variation (CoVs) ranged from 4.22 to 9.77%, and the CoV for all the T2* values independently from the sites was 8.55%. The intraclass correlation coefficient (ICC) for each MRI site was always excellent and the global ICC was 0.995, independently from the sites. The mean absolute difference in patients with pancreatic iron (n = 39) was -0.15 ± 1.38 ms.

CONCLUSION

The gradient-echo T2* MRI technique is an accurate and reproducible means for the quantification of pancreatic iron and may be transferred among MRI scanners by different vendors in several centers.

KEY POINTS

• The gradient-echo T2* MRI technique is an accurate and reproducible means for the quantification of pancreatic iron. • The gradient-echo T2* MRI technique for the quantification of pancreatic iron may be transferred among MRI scanners by different vendors in several centers. • Pancreatic iron might serve as an early predictor of cardiac siderosis and is the strongest overall predictor of glucose dysregulation.

The effect of desferrioxamine chelation versus no therapy in patients with non transfusion-dependent thalassaemia: a multicenter prospective comparison from the MIOT network

We prospectively assessed by magnetic resonance imaging (MRI) the advantages of desferrioxamine (DFO) with respect to the absence of chelation therapy in non transfusion-dependent thalassaemia (NTDT) patients. We considered 18 patients non-chelated and 33 patients who received DFO alone between the two MRI scans. Iron overload was assessed by the T2* technique. Biventricular function parameters were quantified by cine sequences. No patient treated with DFO had cardiac iron. At baseline, only one non-chelated patient showed a pathological heart T2* value (< 20 ms) and he recovered at the follow-up. The percentage of patients who maintained a normal heart T2* value was 100% in both groups. A significant increase in the right ventricular ejection fraction was detected in DFO patients (3.48 ± 7.22%; P = 0.024). The changes in cardiac T2* values and in the biventricular function were comparable between the two groups. In patients with hepatic iron at baseline (MRI liver iron concentration (LIC) ≥ 3 mg/g/dw), the reduction in MRI LIC values was significant only in the DFO group (- 2.20 ± 4.84 mg/g/dw; P = 0.050). The decrease in MRI LIC was comparable between the groups. In conclusion, in NTDT patients, DFO therapy showed no advantage in terms of cardiac iron but its administration allowed an improvement in right ventricular function. Moreover, DFO reduced hepatic iron in patients with significant iron burden at baseline.

Soluble form of transferrin receptor-1 level is associated with the age at first diagnosis and the risk of therapeutic intervention and iron overloading in patients with non-transfusion-dependent thalassemia

We retrospectively evaluated the relationship between serum transferrin receptor-1 (sTfR1) and some fundamental events in the life and the management (the age at diagnosis, the age at the first red blood cells transfusion, the age at splenectomy, and the overall need of chelation therapy) of 111 patients with non-transfusion-dependent thalassemia (NTDT) subdivided in four genetic entities: patients with homozygous or compound heterozygous state for β-thalassemia, patients with triplicated α genotype associated with β heterozygosity, patients with deletional HbH, and patients with the combination of a β defect plus a β chain variant. We found that the group with homozygous or compound heterozygous state for β-thalassemia had the highest sTfR1 levels and that the presence of increased sTfR1 levels (>5 times normal) was associated with a complex and severe history of disease requiring splenectomy, occasional red blood cells transfusions, and early start and continuous iron chelation therapy.The complexity in the management of NTDT patients is an emerging issue due to the wide heterogeneity of clinical behavior. Our data indicate that the measurement of sTfR1 levels, a common laboratory test, could contribute to correctly stratify disease history and the iron chelation strategy in NTDT patients.

Comparative Efficacy and Safety of Oral Iron Chelators and their Novel Combination in Children with Thalassemia

OBJECTIVE

To compare the efficacy and safety of oral iron chelators (Deferiprone and Deferasirox) when used singly and in combination in multi-transfused children with thalassemia.

DESIGN

Prospective comparative study.

SETTING

Thalassemia Center of a medical college affiliated hospital.

PARTICIPANTS AND INTERVENTION

49 multi-transfused children with thalassemia with a mean (SD) age 11.6 (6.21) y received daily chelation therapy with either deferiprone alone (75 mg/kg/day in 3 divided doses), deferasirox alone (30 mg/kg/day single dose) or their daily combination (same dose as monotherapy) for 12 months.

OUTCOME MEASURES

Serum ferritin levels at the start of study, after 6 months and after 12 months. MRI T2* of liver and heart initially and after 6 months of follow up. 24-hour urinary iron excretion values at the outset and after 12 months of chelation therapy. At every visit for blood transfusion, all patients were clinically assessed for any adverse effects; liver and renal functions were monitored 6-monthly.

RESULTS

After 12 months of respective chelation therapy, serum ferritin values decreased from a mean of 3140.5 ng/mL to 2910.0 ng/mL in deferiprone alone group, 3859.2 ng/mL to 3417.4 ng/mL in deferasirox alone group and from 3696.5 ng/mL to 2572.1 ng/mL in the combination group. The combination therapy was more efficacious in causing fall in serum ferritin levels compared to deferiprone and deferasirox monotherapy (P= 0.035 and 0.040, respectively). Results of MRI T2 were equivocal. Combined drug usage produced maximum negative iron balance in the body by maximally increasing the iron excretion in urine from 61.1 umol/day to 343.3 umol/day (P = 0.002). No significant adverse reactions were noticed in either the monotherapy or the combination group.

CONCLUSION

Oral combination therapy of deferiprone and deferasirox appears to be an efficacious and safe modality to reduce serum ferritin in multi-transfused children with thalassemia.

Semi-automated myocardial segmentation of bright blood multi-gradient echo images improves reproducibility of myocardial contours and T2* determination

Objectives

Early detection of iron loading is affected by the reproducibility of myocardial contour assessment. A novel semi-automatic myocardial segmentation method is presented on contrast-optimized composite images and compared to the results of manual drawing.

Materials and methods

Fifty-one short-axis slices at basal, mid-ventricular and apical locations from 17 patients were acquired by bright blood multi-gradient echo MRI. Four observers produced semi-automatic and manual myocardial contours on contrast-optimized composite images. The semi-automatic segmentation method relies on vector field convolution active contours to generate the endocardial contour. After creating radial pixel clusters on the myocardial wall, a combination of pixel-wise coefficient of variance (CoV) assessment and k-means clustering establishes the epicardial contour for each segment.

Results

Compared to manual drawing, semi-automatic myocardial segmentation lowers the variability of T2* quantification within and between observers (CoV of 12.05 vs. 13.86% and 14.43 vs. 16.01%) by improving contour reproducibility (P < 0.001). In the presence of iron loading, semi-automatic segmentation also lowers the T2* variability within and between observers (CoV of 13.14 vs. 15.19% and 15.91 vs. 17.28%).

Conclusion

Application of semi-automatic myocardial segmentation on contrast-optimized composite images improves the reproducibility of T2* quantification.

MRI T2* imaging for assessment of liver iron overload: study of different data analysis approaches

Background Recently, magnetic resonance imaging (MRI) has been established as an effective technique for evaluating iron overload by measuring T2* in the liver. Purpose To investigate the effects of various factors associated with T2* calculation on the resulting measurement and to determine the analysis criterion that provides the most accurate T2* measurements. Material and Methods Both phantom and in vivo MRI experiments were conducted to study the effects of the selected region of interest (ROI) location and size, signal-averaging method, exponential-fitting model, echo truncation, iron-overload severity, and inter-/intra-observer variabilities on T2* measurements. The results were compared to reference values from the scanner processing software. Results The pixel-by-pixel calculation method provided results in better agreement with the reference values from the MRI scanner than the average or median methods. The choice of the exponential fitting model affected the results, depending on signal-to-noise ratio, number of echoes, minimum and maximum echo times, and tissue composition inside the selected ROI. The single-exponential model resulted in smaller error than the bi-exponential or exponential-plus-constant models, where the latter two models showed similar results. The relative performance of the different models and methods was not affected by the degree of iron-overload. Conclusion Various factors associated with the adopted T2* calculation method affect the resulting measurement. In this study, the pixel-by-pixel calculation method and single-exponential model provided the most accurate results based on the conducted phantom and in vivo MRI experiments.

Combined Iron Chelator and Antioxidant Exerted Greater Efficacy on Cardioprotection Than Monotherapy in Iron-Overloaded Rats

Background

Iron chelators are used to treat iron overload cardiomyopathy patients. However, a direct comparison of the benefits of three common iron chelators (deferoxamine (DFO), deferiprone (DFP) and deferasirox (DFX)) or an antioxidant (N-acetyl cysteine (NAC)) with a combined DFP and NAC treatments on left ventricular (LV) function with iron overload has not been investigated.

Methods and Findings

Male Wistar rats were fed with either a normal diet or a high iron diet (HFe group) for 4 months. After 2 months, the HFe-fed rats were divided into 6 groups to receive either: a vehicle, DFO (25 mg/kg/day), DFP (75 mg/kg/day), DFX (20 mg/kg/day), NAC (100 mg/kg/day) or the combined DFP and NAC for 2 months. Our results demonstrated that HFe rats had increased plasma non-transferrin bound iron (NTBI), malondialdehyde (MDA), cardiac iron and MDA levels and cardiac mitochondrial dysfunction, leading to LV dysfunction. Although DFO, DFP, DFX or NAC improved these parameters, leading to improved LV function, the combined DFP and NAC therapy caused greater improvement, leading to more extensively improved LV function.

Conclusions

The combined DFP and NAC treatment had greater efficacy than monotherapy in cardioprotection through the reduction of cardiac iron deposition and improved cardiac mitochondrial function in iron-overloaded rats.

Influence of the analysis technique on estimating hepatic iron content using MRI

PURPOSE

To investigate the effect of the analysis technique on estimating hepatic iron content using MRI.

MATERIALS AND METHODS

We evaluated the influences of single-exponential (EXP), bi-exponential (BEXP), and exponential-plus-constant (CEXP) models; and pixel-wise (MAP), average (AVG), and median (MED) signal calculation methods on T2* measurement using numerical simulations, calibrated phantoms, and nine patients scanned on 3 Tesla MRI, based on regression, correlation, and t-test statistical analysis.

RESULTS

The T2* measurement error varied from 9 to 51% in the numerical simulations (T2*: 5-20 ms), depending on signal-to-noise ratio (SNR; range: 8-233) with significant (P < 0.05) difference between actual and predicted values. The MAP method performed well (error < 10%) at high SNR (>100), but resulted in severe estimation errors at low SNR (<50). The EXP model resulted in significant measurement differences (P < 0.05) compared with all other methods, irrespective of SNR. In vivo T2* values ranged from 3.1 to 53.6 ms, depending on the amount of iron overload and implemented analysis method. The BEXP (range: 3.7-50 ms) and CEXP (range: 3.8-53.6 ms) models, and the AVG (range: 3.2-38.8 ms) and MED (range: 3.1-38.5 ms) methods provided more accurate measurements than the EXP model (range: 3.1-18.3 ms) and MAP (range: 3.8-53.6 ms) method, respectively (P < 0.05). The BEXP and CEXP models provided very similar measurements (P > 0.87). Similarly, the AVG and MED methods provided very similar results (P > 0.97), with slightly better performance of the AVG method.

CONCLUSION

Different analysis techniques show different performances based on the fitting model and signal calculation method. Based on this study, the CEXP model and AVG method are recommended due to simpler implementation and less influence by the selected analysis region. J. Magn. Reson. Imaging 2016;44:1448-1455.

Early Cardiac Involvement and Risk Factors for the Development of Arrhythmia in Patients With β-Thalassemia Major

BACKGROUND

Cardiac iron overload is the most serious complication in thalassemia; even patients treated with intensive chelation suffer at a certain point from cardiomyopathy and arrhythmia.

AIM

The aim of the study was to identify indicators of cardiac dysfunction in thalassemia as well as risk factors associated with the development of arrhythmia.

PATIENTS AND METHODS

A total of 45 patients with β-thalassemia major were enrolled in this cross-sectional study. Patients were divided into 2 groups according to the absence (group A) or the presence of arrhythmia (group B). Cardiac parameters in thalassemic groups were evaluated using 24-Holter recording, Stress electrocardiogram, and M-mode echocardiography. Serum ferritin and Cardiac T2* were used to assess the iron status.

RESULTS

Group B showed significantly higher values of cardiac T2* and serum ferritin (P<0.05). Group B patients had significantly higher maximum heart rate with significant attacks of bradycardia and ST segment changes. In addition, they achieved a lower percentage of maximum age predicted heart rate and lower values of maximum metabolic equivalents (P<0.05). Significantly higher values of the left atrial diameter, the interventricular septum diameter, and the left-ventricle posterior wall diameter (P<0.05) were identified in group B.

CONCLUSIONS

The increase in left atrial diameter, interventricular septum diameter, and left-ventricle posterior wall diameter seems to be related to the development of arrhythmia in patients with thalassemia, especially supraventricular arrhythmias.

Extramedullary hematopoiesis is associated with lower cardiac iron loading in chronically transfused thalassemia patients

The aim of this study was to evaluate, in a large cohort of chronically transfused patients, whether the presence of extramedullary hematopoiesis (EMH) accounts for the typical patterns of cardiac iron distribution and/or cardiac function parameters. We retrospectively selected 1,266 thalassemia major patients who had undergone regular transfusions (611 men and 655 women; mean age: 31.3 ± 8.9 years, range: 4.2-66.6 years) and were consecutively enrolled within the Myocardial Iron Overload in Thalassemia network. The presence of EMH was evaluated based on steady-state free precession sequences; cardiac and liver iron overloads were quantified using a multiecho T2* approach; cardiac function parameters and pulmonary diameter were quantified using the steady-state free precession sequences; and myocardial fibrosis was evaluated using the late gadolinium enhancement technique. EMH was detected in 167 (13.2%) patients. The EMH+ patients had significantly lower cardiac iron overload than that of the EMH- patients (P = 0.003). The patterns of cardiac iron distribution were significantly different in the EMH+ and EMH- patients (P < 0.0001), with a higher prevalence of patients with no myocardial iron overload and heterogeneous myocardial iron overload and no significant global heart iron in the EMH+ group EMH+ patients had a significantly higher left ventricle mass index (P = 0.001) and a significantly higher pulmonary artery diameter (P = 0.002). In conclusion, in regularly transfused thalassemia patients, EMH was common and was associated with a thalassemia intermedia-like pattern of cardiac iron deposition despite regular transfusion therapy.

Impaired hepcidin expression in alpha-1-antitrypsin deficiency associated with iron overload and progressive liver disease

Liver disease due to alpha-1-antitrypsin deficiency (A1ATD) is associated with hepatic iron overload in a subgroup of patients. The underlying cause for this association is unknown. The aim of the present study was to define the genetics of this correlation and the effect of alpha-1-antitrypsin (A1AT) on the expression of the iron hormone hepcidin. Full exome and candidate gene sequencing were carried out in a family with A1ATD and hepatic iron overload. Regulation of hepcidin expression by A1AT was studied in primary murine hepatocytes. Cells co-transfected with hemojuvelin (HJV) and matriptase-2 (MT-2) were used as a model to investigate the molecular mechanism of this regulation. Observed familial clustering of hepatic iron overload with A1ATD suggests a genetic cause, but genotypes known to be associated with hemochromatosis were absent. Individuals homozygous for the A1AT Z-allele with environmental or genetic risk factors such as steatosis or heterozygosity for the HAMP non-sense mutation p.Arg59* presented with severe hepatic siderosis. In hepatocytes, A1AT induced hepcidin mRNA expression in a dose-dependent manner. Experiments in overexpressing cells show that A1AT reduces cleavage of the hepcidin inducing bone morphogenetic protein co-receptor HJV via inhibition of the membrane-bound serine protease MT-2. The acute-phase protein A1AT is an inducer of hepcidin expression. Through this mechanism, A1ATD could be a trigger of hepatic iron overload in genetically predisposed individuals or patients with environmental risk factors for hepatic siderosis.

Multiparametric Cardiac Magnetic Resonance Survey in Children With Thalassemia Major

Background—

Cardiovascular magnetic resonance (CMR) plays a key role in the management of thalassemia major patients, but few data are available in pediatric population. This study aims at a retrospective multiparametric CMR assessment of myocardial iron overload, function, and fibrosis in a cohort of pediatric thalassemia major patients.

Methods and Results—

We studied 107 pediatric thalassemia major patients (61 boys, median age 14.4 years). Myocardial and liver iron overload were measured by T2* multiecho technique. Atrial dimensions and biventricular function were quantified by cine images. Late gadolinium enhancement images were acquired to detect myocardial fibrosis. All scans were performed without sedation. The 21.4% of the patients showed a significant myocardial iron overload correlated with lower compliance to chelation therapy ( P <0.013). Serum ferritin ≥2000 ng/mL and liver iron concentration ≥14 mg/g/dw were detected as the best threshold for predicting cardiac iron overload ( P =0.001 and P <0.0001, respectively). A homogeneous pattern of myocardial iron overload was associated with a negative cardiac remodeling and significant higher liver iron concentration ( P <0.0001). Myocardial fibrosis by late gadolinium enhancement was detected in 15.8% of the patients (youngest children 13 years old). It was correlated with significant lower heart T2* values ( P =0.022) and negative cardiac remodeling indexes. A pathological magnetic resonance imaging liver iron concentration was found in the 77.6% of the patients.

Conclusions—

Cardiac damage detectable by a multiparametric CMR approach can occur early in thalassemia major patients. So, the first T2* CMR assessment should be performed as early as feasible without sedation to tailor the chelation treatment. Conversely, late gadolinium enhancement CMR should be postponed in the teenager age.

Role of vitamin C as an adjuvant therapy to different iron chelators in young β-thalassemia major patients: efficacy and safety in relation to tissue iron overload

BACKGROUND

Vitamin C, as antioxidant, increases the efficacy of deferoxamine (DFO).

AIM

To investigate the effects of vitamin C as an adjuvant therapy to the three used iron chelators in moderately iron-overloaded young vitamin C-deficient patients with β-thalassemia major (β-TM) in relation to tissue iron overload.

METHODS

This randomized prospective trial that included 180 β-TM vitamin C-deficient patients were equally divided into three groups (n = 60) and received DFO, deferiprone (DFP), and deferasirox (DFX). Patients in each group were further randomized either to receive vitamin C supplementation (100 mg daily) or not (n = 30). All patients received vitamin C (group A) or no vitamin C (group B) were followed up for 1 yr with assessment of transfusion index, hemoglobin, iron profile, liver iron concentration (LIC) and cardiac magnetic resonance imaging (MRI) T2*.

RESULTS

Baseline vitamin C was negatively correlated with transfusion index, serum ferritin (SF), and LIC. After vitamin C therapy, transfusion index, serum iron, SF, transferrin saturation (Tsat), and LIC were significantly decreased in group A patients, while hemoglobin and cardiac MRI T2* were elevated compared with baseline levels or those in group B without vitamin C. The same improvement was found among DFO-treated patients post-vitamin C compared with baseline data. DFO-treated patients had the highest hemoglobin with the lowest iron, SF, and Tsat compared with DFP or DFX subgroups.

CONCLUSIONS

Vitamin C as an adjuvant therapy possibly potentiates the efficacy of DFO more than DFP and DFX in reducing iron burden in the moderately iron-overloaded vitamin C-deficient patients with β-TM, with no adverse events.

Efficacy and safety of a novel combination of two oral chelators deferasirox/deferiprone over deferoxamine/deferiprone in severely iron overloaded young beta thalassemia major patients

OBJECTIVE

Minimal data are available on the combined two oral iron chelators in β-thalassemia major (β-TM). Comparison of safety, efficacy, compliance, treatment satisfaction, and quality of life (QoL) of two regimens: deferiprone (DFP) and deferoxamine (DFO) versus DFP and deferasirox (DFX) were studied.

METHODS

A prospective randomized trial (NCT01511848) was conducted on 96 young β-TM patients with severe iron overload. Patients were randomized to receive either DFP with DFO (arm 1) or DFP and DFX (arm 2). Efficacy endpoints were the difference between two groups in the change of serum ferritin (SF), liver iron concentration (LIC), cardiac MRI, and quality of life (QoL).

RESULTS

In both arms, SF and LIC at 12 months were significantly lower, and geometric mean cardiac T2* was higher compared to baseline. On regression analysis of change in each studied variable against time, significant difference between slopes of the two groups regarding cardiac T2* (P = 0.001 with more improvement in DFP/DFX patients) was found with no significant difference in the slopes of SF and LIC (P = 0.218 and 0.340).

CONCLUSION

Both iron chelation combination regimens were equally effective in reducing iron overload and improving QoL.DFP/DFX combination proved superior in improving cardiac T2*, treatment compliance, and patients satisfaction with no greater adverse events.

Sustained improvements in myocardial T2* over 2 years in severely iron-overloaded patients with beta thalassemia major treated with deferasirox or deferoxamine

Long-term controlled studies are needed to inform on the clinical benefit of chelation therapy for myocardial iron removal in transfusion-dependent beta thalassemia patients. In a 1-year nonrandomized extension to the CORDELIA study, data collected from patients with myocardial siderosis provided additional information on deferasirox or deferoxamine (DFO) efficacy and safety. Myocardial (m)T2* increased from baseline 11.6 to 15.9 ms in patients receiving deferasirox for 24 months (n = 74; geometric mean [Gmean ] ratio of month 24/baseline 1.38 [95% confidence interval 1.28, 1.49]) and from 10.8 to 14.2 ms in those receiving DFO (n = 29; Gmean ratio 1.33 [1.13, 1.55]; P = 0.93 between groups). Improved mT2* with deferasirox was evident across all subgroups evaluated irrespective of baseline myocardial (mT2* < 10 vs. ≥ 10 ms) or liver (LIC <15 vs. ≥15 mg Fe/g dw) iron burden. Mean LVEF was stable and remained within normal limits with deferasirox or DFO. Liver iron concentration decreased from high baseline values of 30.6 ± 18.0 to 14.4 ± 16.6 mg Fe/g dw at month 24 in deferasirox patients and from 36.8 ± 15.6 to 11.0 ± 12.1 mg Fe/g dw in DFO patients. The long-term safety profile of deferasirox or DFO was consistent with previous reports; serious drug-related AEs were reported in 6.8% of deferasirox and 6.9% of DFO patients. Continued treatment of severely iron-overloaded beta thalassemia patients with deferasirox or DFO led to sustained improvements in myocardial iron irrespective of high or low baseline myocardial or liver iron burden, in parallel with substantial improvements in liver iron (Clinicaltrials.gov identifier: NCT00600938).

The influence of the analysis technique on estimating liver iron overload using magnetic resonance imaging T2* quantification

Iron toxicity is the major cause of tissue damage in patients with iron overload. Iron deposits mainly in the liver, where its concentration closely correlates with whole body iron overload. Different techniques have been proposed for estimating iron content, with liver biopsy being the gold standard despite its invasiveness and influence by sampling error. Recently, magnetic resonance imaging (MRI) has been established as an effective technique for evaluating iron overload by measuring T2(*) in the liver. However, various factors associated with the adopted analysis technique, mainly the exponential fitting model and signal averaging method, affect the resulting measurements. In this study, we evaluate the influences of these factors on T2(*) measurement in numerical phantom, calibrated phantoms, and nine patients with different degrees of iron overload. The results show different performances among the fitting models and signal averaging methods, which are affected by SNR, image quality and signal homogeneity inside the selected ROI for analysis.

Prevalence and distribution of iron overload in patients with transfusion-dependent anemias differs across geographic regions: results from the CORDELIA study

OBJECTIVES

The randomized comparison of deferasirox to deferoxamine for myocardial iron removal in patients with transfusion-dependent anemias (CORDELIA) gave the opportunity to assess relative prevalence and body distribution of iron overload in screened patients.

METHODS

Patients aged ≥ 10 yr with transfusion-dependent anemias from 11 countries were screened. Data were summarized descriptively, overall and across regions.

RESULTS

Among 925 patients (99.1% with β-thalassemia major; 98.5% receiving prior chelation; mean age 19.2 yr), 36.7% had myocardial iron overload (myocardial T2* ≤ 20 ms), 12.1% had low left ventricular ejection fraction. Liver iron concentration (LIC) (mean 25.8 mg Fe/g dw) and serum ferritin (median 3702 ng/mL) were high. Fewer patients in the Middle East (ME; 28.5%) had myocardial T2* ≤ 20 ms vs. patients in the West (45.9%) and Far East (FE, 40.9%). Patients in the West had highest myocardial iron burden, but lowest LIC (26.9% with LIC < 7 mg Fe/g dw) and serum ferritin. Among patients with normal myocardial iron, a higher proportion of patients from the ME and FE had LIC ≥ 15 than < 7 mg Fe/g dw (ME, 56.7% vs. 17.2%; FE, 78.6% vs. 7.8%, respectively), a trend which was less evident in the West (44.6% vs. 33.9%, respectively). Transfusion and chelation practices differed between regions.

CONCLUSIONS

Evidence of substantial myocardial and liver iron burden across regions revealed a need for optimization of effective, convenient iron chelation regimens. Significant regional variation exists in myocardial and liver iron loading that are not well explained; improved understanding of factors contributing to differences in body iron distribution may be of clinical benefit.

A systematic review and meta-analysis of deferiprone monotherapy and in combination with deferoxamine for reduction of iron overload in chronically transfused patients with β-thalassemia

β-Thalassemia major (β-TM) patients require life-long blood transfusions, resulting in iron overload with multi-organ morbidity and mortality. Evidence from small randomized controlled trials (RCTs) published to date for deferiprone (DFP) monotherapy or in combination with deferoxamine (DFO) is unclear. We summarized evidence on the efficacy of DFP monotherapy compared to DFO, and DFP-DFO combination therapy compared to DFP or DFO monotherapy in chronically transfused β-TM. We searched four electronic databases and examined the grey literature. Two authors independently assessed trial quality and extracted data. We calculated the relative risk for dichotomous outcomes and mean difference (MD) for continuous outcomes. We identified 15 RCTs (1003 participants) that met the inclusion criteria. Deferiprone was more efficacious than DFO in improving cardiac ejection fraction [MD 2.88, 95% CI (95% confidence interval) 1.12 to 4.64, p = 0.001) and endocrine dysfunction (MD 0.09, 95% CI 0.08 to 0.10, p < 0.00001). The DFP-DFO combination therapy was more efficacious than DFP or DFO monotherapy in improving cardiac ejection fraction (MD 5.67, 95% CI 1.32 to 10.02, p = 0.008). There was no significant difference in all other outcomes examined. Meta-analysis on changes in myocardial iron content was not possible due to differences in data presentation. The quality of evidence for all outcomes was low. There is currently insufficient evidence to show that DFP is superior to DFO in the treatment of iron overload. The use of DFP must be weighed against the potential side-effects, patient compliance and preference. Large RCTs with clinically relevant outcomes are required.

The Role of Magnetic Resonance Imaging in the Evaluation of Thalassemic Syndromes: Current Practice and Future Perspectives

Iron can be deposited in all internal organs, leading to different types of functional abnormalities. However, myocardial iron overload that contributes to heart failure remains one of the main causes of death in thalassemia major. Using magnetic resonance imaging, tissue iron is detected indirectly by the effects on relaxation times of ferritin and hemosiderin iron interacting with hydrogen nuclei. The presence of iron in the human body results in marked alterations of tissue relaxation times. Currently, cardiovascular magnetic resonance using T2* is routinely used in many countries to identify patients with myocardial iron loading and guide chelation therapy, specifically tailored to the heart. Myocardial T2* is the only clinically validated non-invasive measure of myocardial iron loading and is superior to surrogates such as serum ferritin, liver iron, ventricular ejection fraction and tissue Doppler parameters. Finally, the substantial amelioration of patients’ survival, allows the detection of other organs’ abnormalities due to iron overload, apart from the heart, missed in the past. Recent studies revealed that iron deposition has a different pattern in various parenchymal organs, which is independent from serum ferritin and follows an individual way after chelation treatment application. This new upcoming reality orders a closer monitoring of all organs of the body in order to detect preclinical lesions and early apply adequate treatment.