Myocardial deformation in iron overload cardiomyopathy: speckle tracking imaging in a beta-thalassemia major population

Speckle tracking echocardiography and β-thalassemia major. A systematic review

Heart disease is among the primary causes of morbidity and mortality in β-thalassemia major (β-TM). Conventional echocardiography has failed to identify myocardial dysfunction at an early stage among these patients, thus speckle tracking echocardiography (STE) has been lately used. The objectives of this review were to 1) identify all published studies having evaluated myocardial strain among β-TM patients, 2) gather their results, 3) compare their findings and 4) propose recommendations based on these data. Literature search was conducted in PubMed, SCOPUS and Cohrane Library. Data regarding left ventricular global longitudinal (LV-GLS), circumferential (LV-GCS) and radial strain (LV-GRS), right ventricular longitudinal strain (RV-GLS), left and right atrial strain were extracted. Thirty-five studies (34 original articles and 1 meta-analysis) have met the inclusion criteria. LV-GLS has been reported being worse in patients compared to controls in 13 of 21 studies, LV-GCS in 7 of 11 studies, LV-GRS in 6 of 7 studies, RV-GLS in 2 of 3 studies and left atrial strain in all case-control studies. Myocardial iron overload (MIO) patient subgroups had worse LV-GLS in 6 of 15 studies, LV-GCS in 2 of 7 studies and LV-GRS in none of 7 studies. A small number of studies suggest left atrial strain correlation with electrical atrial ectopy and atrial fibrillation. It is suggested that STE should be applied supplementary to conventional echocardiography for early identification of myocardial dysfunction among β-TM patients. Potential myocardial strain utilities could be screening for myocardial iron overload, left ventricular diastolic dysfunction and atrial fibrillation.

The potential impact of hereditary hemochromatosis on the heart considering the disease stage and patient age-the role of echocardiography

Background

Hereditary hemochromatosis (HH) is a genetic disease that leads to increased iron accumulation in several organs. Cardiomyocytes are highly susceptible to this damage owing to their high iron uptake, and cardiovascular complications account for 1/3 of the deaths in the natural course of HH. Additionally, excess iron intake and associated oxidative stress may accelerate the aging of the cardiovascular system, regardless of the age of patients with HH. We aimed to investigate the role of standard and speckle-tracking echocardiography (STE) in revealing heart differences in patients with HH considering the disease stage and the patient age.

Methodology

Consecutive patients with HH (n = 58) without heart pathologies (except hypertension) and 29 age- and sex-matched healthy individuals underwent echocardiography. Patients were compared according to the time since HH diagnosis (the recently diagnosed HH group [31 patients] with diagnosed HH for less than 6 months and had no more than one venesection; the medium group [11 patients] with diagnosed HH between 6 and 24 months; and the long-lasting group [16 patients] with diagnosed HH for more than 2 years) and the quartile contribution of their age.

Results

Standard echocardiography revealed differences in diastolic parameters between patients with HH and controls, which were the most prominent between healthy and long-lasting HH patients. Regarding systolic function, left ventricular ejection fraction was lower in HH patients, with the most evident differences between the healthy and recently diagnosed HH patients. STE revealed additional differences in systolic parameters, with LV rotation the worst in recently diagnosed patients and its increase in patients with medium and long-lasting HH. Significantly worse peak systolic longitudinal strain values were observed in all patients with HH. Analyses of the results according to the age quartiles of patients with HH revealed that some changes ocurred earlier than expected according to age.

Conclusions

Echocardiography can reveal possible heart damage in HH patients at different stages of the disease and highlight potential features of accelerated myocardial aging in these patients.

Clinical Complications and Their Management

The diversity of disease-related complications among patients with β-thalassemia is complicated by the wide spectrum of genotypes and clinical risk factors. The authors herein present the different complications seen in patients with β-thalassemia, the pathophysiology underlying these complications and their management.

Cardiac Magnetic Resonance Strain in Beta Thalassemia Major Correlates with Cardiac Iron Overload

BACKGROUND

Beta thalassemia major (Beta-TM) is an inherited condition which presents at around two years of life. Patients with Beta-;TM may develop cardiac iron toxicity secondary to transfusion dependence. Cardiovascular magnetic resonance (CMR) T2*, a technique designed to quantify myocardial iron deposition, is a driving component of disease management. A decreased T2* value represents increasing cardiac iron overload. The clinical manifestation is a decline in ejection fraction (EF). However, there may be early subclinical changes in cardiac function that are not detected by changes in EF. CMR-derived strain assesses myocardial dysfunction prior to decline in EF. Our primary aim was to assess the correlation between CMR strain and T2* in the Beta-TM population.

METHODS

Circumferential and longitudinal strain was analyzed. Pearson's correlation was calculated for T2* values and strain in the Beta-TM population.

RESULTS

We identified 49 patients and 18 controls. Patients with severe disease (low T2*) were found to have decreased global circumferential strain (GCS) in comparison to other T2* groups. A correlation was identified between GCS and T2* (r = 0.5; p < 0.01).

CONCLUSION

CMR-derived strain can be a clinically useful tool to predict early myocardial dysfunction in Beta-TM.

Evaluation of left ventricular function and myocardial deformation in children with beta-thalassemia major by real-time three-dimensional (four-dimensional) and speckle tracking echocardiography

AIM

This study aimed to evaluate the role of real-time three-dimensional (four-dimensional) and speckle tracking echocardiography for early detection of left ventricular systolic dysfunction and also for the relationship between myocardial deformation parameters and myocardial iron load which is measured by cardiac magnetic resonance relaxation time T2* values in asymptomatic children with beta-thalassemia major.

MATERIAL AND METHODS

This multicenter cross-sectional study included 40 patients (mean age 15.4 ± 2.9, 42.1% male) and 40 healthy children whose age, gender, and body mass index-matched with patients. Each participant underwent conventional echocardiography and tissue Doppler imaging. Left ventricular ejection fraction; global longitudinal, circumferential, radial strains; twist; and torsion were measured by real-time three-dimensional and speckle tracking echocardiography. Cardiac magnetic resonance imaging T2* was measured in patients.

RESULTS

Left ventricular global longitudinal, circumferential, and radial strains were decreased despite preserved global ventricular function in patients compared to healthy children (p = p = .029, p = p < .001, p = .003, respectively). There were no statistically significant differences between patients with T2* ≥ 20 ms and patients with T2* < 20 ms for all echocardiographic parameters. Also, there were no significant correlations between all echocardiographic parameters and T2* values in all patients, those with T2* ≥ 20 ms, and T2* < 20 ms.

CONCLUSION

We found that even in asymptomatic children with beta-thalassemia major, left ventricular longitudinal, circumferential and, radial functions were impaired by real-time three-dimensional (four-dimensional) and speckle tracking echocardiography. This novel echocardiographic method might be an important tool for detecting subclinical left ventricular systolic dysfunction irrespective of T2* values.

Cardiac Magnetic Resonance at 3.0 T in Patients With C282Y Homozygous Hereditary Hemochromatosis: Superiority of Radial and Circumferential Strain Over Cardiac T2* Measurements at Baseline and at Post Venesection Follow-up

BACKGROUND

Iron-overload cardiomyopathy initially manifests with diastolic dysfunction and can progress to dilated cardiomyopathy if untreated. Previous studies have shown that patients with primary and secondary hemochromatosis can have subclinical left ventricle dysfunction with abnormalities on strain imaging. This study aimed to evaluate the relationship between cardiac T2* values and myocardial-wall strain in patients with hereditary hemochromatosis (HH) at the time of diagnosis and after a course of venesection treatment.

MATERIALS AND METHODS

Baseline cardiac magnetic resonance (CMR) at 3 T was performed in 19 patients with newly diagnosed HH with elevated serum ferritin levels and repeated after a course of treatment with venesection. Quantitative T2* mapping and strain analysis were performed offline using dedicated relaxometry fitting and feature-tracking software.

RESULTS

The majority (84%) of patients had normal baseline myocardial T2* values (mean 19.3 ms, range 8.9 to 31.2 ms), which improved significantly after venesection (mean 24.1 ms, range 11 to 38.1 ms) ( P =0.021). Mean global radial strain significantly improved from 25.0 (range: 15.6 to 32.9) to 28.3 (range: 19.8 to 35.8) ( P =0.001) and mean global circumferential strain improved, decreasing from -15.7 (range: -11.1 to -19.2) to -17.1 (range: -13.0 to -20.1) ( P =0.001).

CONCLUSION

Patients with HH may have normal T2* values in the presence of subclinical left ventricle dysfunction, which can be detected by abnormal radial and circumferential strain. As strain imaging improves following venesection in HH, it may serve as a useful biomarker to guide treatment.

Global longitudinal strain for detection of cardiac iron overload in patients with thalassemia: a meta-analysis of observational studies with individual-level participant data

BACKGROUND

Although cardiac magnetic resonance (CMR) is the most reliable tool for assessment of CIO in patients with thalassemia, it is not always readily available. Recent studies have explored the potential of GLS as an alternative for diagnosis of CIO. We aimed to investigate the efficacy of global longitudinal strain (GLS) for detection of cardiac iron level (CIO).

METHODS

We searched SCOPUS, MEDLINE, and Embase to identify the studies which used GLS for assessment of CIO. We searched for individual participant data (IPD) in eligible studies to perform ROC curve analysis. CMR with a T2* cut-off value of 20 ms was considered as the gold standard. A meta-analysis was performed and the risk of bias was assessed using the JBI Checklist.

RESULTS

A total of 14 studies with 789 thalassemia patients (310 and 430 with and without CIO respectively and 49 with undetermined condition) were considered eligible for meta-analysis. IPDs of 405 participants were available. GLS was significantly lower in patients with CIO (-17.5 ± 2.7%) compared to those without CIO (-19.9 ± 2.3%; WMD = 1.6%, 95% CI = [0.76-2.4], p = 0.001, I² = 77.1%) and to normal population (-20.61 ± 2.26%; WMD = 2.2%, 95% CI = [0.91-3.5], p = 0.001, I² = 83.9%). A GLS < -19.5% could predict CIO with 92.8% sensitivity and 34.63% specificity (AUC = 0.659, 95% CI = [0.6-0.72], p-value < 0.0001). A GLS value < -6% has 100% positive predictive and ≥ -24.5% has 100% negative predictive values for detection of CIO.

CONCLUSIONS

According to our study, GLS is a strong predictor of CIO and when CMR is not available, it may be a useful screening method for identification of CIO in thalassemia patients.

Significance of Cardiac Magnetic Resonance Feature Tracking of the Right Ventricle in Predicting Subclinical Dysfunction in Patients with Thalassemia Major

In patients with thalassemia major (TM), cardiac magnetic resonance feature-tracking (CMR-FT) has been shown to be an effective method for diagnosing subclinical left ventricular (LV) dysfunction. This study aimed to determine whether CMR-FT could detect abnormal RV dysfunction in patients with a normal right ventricular ejection fraction (RVEF). We performed a retrospective analysis of TM patients admitted to Dubai’s Rashid Hospital between July 2019 and March 2021. The inclusion criteria were TM patients with SSFP cine with T2* (T2*-weighted imaging), while exclusion criteria included any other cardiovascular disease. When there was no myocardial iron overload (MIO) (T2* ≥ 20 ms) and when there was significant MIO (T2* < 20 ms), the CMR-FT was used to correlate with EF. Among the 89 participants, there were 46 men (51.7%) and 43 women (48.3%), with a mean age of 26.14 ± 7.4 years (range from 10 to 48 years). Forty-six patients (51.69%) did not have MIO, while 43 individuals did (48.31%). Thirty-nine patients (32.6%) were diagnosed with severe MIO, while seventeen (19.1%) were diagnosed with mild to moderate MIO. A significant correlation existed between RVEF and T2* values (r = 0.274, p = 0.014) and between left ventricular ejection fraction (LVEF) and T2* values (r = 0.256, p = 0.022). Using a multiple logistic regression model with predictors such as right ventricular longitudinal strain (RVGLS), LV ejection fraction (LV EF), and hemoglobin, abnormal myocardial iron overload can be predicted. This model demonstrates an AUC of 78.3%, a sensitivity of 72%, and a specificity of 76%. In the group with preserved RVEF > 53%, the left ventricular radial strain (LVGRS) (p = 0.001), right ventricular radial strain (RVGRS) (p = 0.000), and right ventricular basal circumferential strain (RVGCS-basal) (p = 0.000) CMR-FT strain values are significantly lower than those of the control group (p > 0.05). There was no significant correlation between the LVGLS and T2*. RVGLS was ranked among the most accurate predictors of abnormal myocardial iron overload. The LVGRS, RVGRS, and RVGCS-basal CMR-FT strain values were the best predictors of subclinical RV dysfunction in the group with preserved RVEF. The most accurate way to diagnose MIO is still T2*, but FT-strain can help us figure out how MIO affects the myocardium from a pathophysiological point of view.

Advanced Echocardiography Techniques: The Future Stethoscope of Systemic Diseases

Cardiovascular disease (CVD) has been showing patterns of extensive rise in prevalence in the contemporary era, affecting the quality of life of millions of people and leading the causes of death worldwide. It has been a provocative challenge for modern medicine to diagnose CVD in its crib, owing to its etiological factors being attributed to a large array of systemic diseases, as well as its non-binary hideous nature that gradually leads to functional disability. Novel echocardiography techniques have enabled the cardiac ultrasound to provide a comprehensive analysis of the heart in an objective, feasible, time- and cost-effective manner. Speckle tracking echocardiography, contrast echocardiography, and 3D echocardiography have shown the highest potential for widespread use. The uses of novel modalities have been elaborately demonstrated in this study as a proof of concept that echocardiography has a place in routine general practice with supportive evidence being as recent as its role in the concurrent COVID-19 pandemic. Despite such evidence, many uses remain off-label and unexploited in practice. Generalization of echocardiography at the point of care can become a much-needed turning point in the clinical approach to case management. To actualize such aspirations, we recommend further prospective and interventional studies to examine the effect of implementing advanced techniques at the point of care on the decision-making process and evaluate their effectiveness in prevention of cardiovascular morbidities and mortalities.

Association between left ventricular strain and cardiac iron load in beta-thalassaemia major: a cardiac magnetic resonance study

OBJECTIVE

To evaluate the utility of cardiac magnetic resonance feature tracking-derived left ventricular strain in assessing cardiac dysfunction and investigate the correlation between left ventricular strain and myocardial T2* in patients with beta-thalassaemia major.

METHODS

Forty-two patients with beta-thalassaemia major, having a mean age of 22.49 ± 8.48 years, and age-matched healthy controls were enrolled in the study. The observer drew regions of interest on the interventricular septum, and T2* decay curves were calculated accordingly. The short-axis cine images were used to derive left ventricular circumferential and radial strains, and the long-axis four-chamber and two-chamber images were used to assess left ventricular longitudinal strain.

RESULTS

The mean global left ventricular strains were lower in beta-thalassaemia major patients than the controls (p < 0.05). Left ventricular strains of beta-thalassaemia major patients with cardiac T2* values of > 20 ms were also significantly reduced compared with the controls (p < 0.05); there was no difference between the mean left ventricular ejection fractions of the two groups (p = 0.84). Cardiac T2* showed a weak correlation with left ventricular ejection fraction (r = 0.33, p = 0.03), while the left ventricular circumferential strain showed a good positive correlation with cardiac T2* (r = 0.6, p < 0.0001).

CONCLUSION

Compared with healthy controls, patients with beta-thalassaemia major, including those with myocardial T2* values of >20 ms, showed reduced global left ventricular strains. Left ventricular circumferential strain was positively correlated with myocardial T2*. Left ventricular strain analysis using cardiac magnetic resonance feature tracking may have utility in beta-thalassaemia major assessment.Key FindingsPatients with beta-thalassaemia major, including those with myocardial T2* values of >20 ms, had reduced global left ventricular strains.Cardiac T2* showed a weak correlation with left ventricular ejection fraction, while the left ventricular circumferential strain showed a good positive correlation with cardiac T2*.ImportanceLeft ventricular strain using cardiac magnetic resonance feature tracking might be used as an adjunct in assessing cardiac functions in beta-thalassaemia major.

Speckle-Tracking Echocardiography in Cardio-Oncology and Beyond

Speckle-tracking echocardiography has enabled clinicians to detect changes in myocardial function with more sensitivity than that afforded by traditional diastolic and systolic functional measurements, including left ventricular ejection fraction. Speckle-tracking echocardiography enables evaluation of myocardial strain in terms of strain (percent change in length of a myocardial segment relative to its length at baseline) and strain rate (strain per unit of time). Both measurements have potential for use in diagnosing and monitoring the cardiovascular side effects of cancer therapy. Regional and global strain measurements can independently predict outcomes not only in patients who experience cardiovascular complications of cancer and cancer therapy, but also in patients with a variety of other clinical conditions. This review and case series examine the clinical applications and overall usefulness of speckle-tracking echocardiography in cardio-oncology and, more broadly, in clinical cardiology.

Pathogenesis, Diagnosis, and Clinical Implications of Hereditary Hemochromatosis-The Cardiological Point of View

Hereditary hemochromatosis (HH) is a genetic disease leading to excessive iron absorption, its accumulation, and oxidative stress induction causing different organ damage, including the heart. The process of cardiac involvement is slow and lasts for years. Cardiac pathology manifests as an impaired diastolic function and cardiac hypertrophy at first and as dilatative cardiomyopathy and heart failure with time. From the moment of heart failure appearance, the prognosis is poor. Therefore, it is crucial to prevent those lesions by upfront therapy at the preclinical phase of the disease. The most useful diagnostic tool for detecting cardiac involvement is echocardiography. However, during an early phase of the disease, when patients do not present severe abnormalities in serum iron parameters and severe symptoms of other organ involvement, heart damage may be overlooked due to the lack of evident signs of cardiac dysfunction. Considerable advancement in echocardiography, with particular attention to speckle tracking echocardiography, allows detecting discrete myocardial abnormalities and planning strategy for further clinical management before the occurrence of substantial heart damage. The review aims to present the current state of knowledge concerning cardiac involvement in HH. In addition, it could help cardiologists and other physicians in their everyday practice with HH patients.

Predictors of cardiovascular events and all-cause of death in patients with transfusion-dependent myelodysplastic syndrome

Cardiovascular disease (CVD) involves the second cause of death in low-risk myelodysplastic syndrome (MDS) population. Prospective study to characterise the CVD and to identify predictors for the combined event (CE) cardiovascular event and/or all-cause mortality in transfusion dependent low-risk MDS patients. Thirty-one patients underwent a cardiac assessment including biomarkers and cardiac magnetic resonance (cMR) with parametric sequences (T1, T2 and T2* mapping) and myocardial deformation by feature tracking (FT) and were analysed for clonal hematopoiesis of indeterminate potential mutations. Cardiac assessment revealed high prevalence of unknown structural heart disease (51% cMR pathological findings). After 2·2 [0·44] years follow-up, 35·5% of patients suffered the CE: 16% death, 29% cardiovascular event. At multivariate analysis elevated NT-proBNP ≥ 486pg/ml (HR 96·7; 95%-CI 1·135-8243; P = 0·044), reduced native T1 time < 983ms (HR 44·8; 95%-CI 1·235-1623; P = 0·038) and higher left ventricular global longitudinal strain (LV-GLS) (HR 0·4; 95%-CI 0·196-0·973; P = 0·043) showed an independent prognostic value. These variables, together with the myocardial T2* time < 20ms, showed an additive prognostic value (Log Rank: 12·4; P = 0·001). In conclusion, low-risk MDS patients frequently suffer CVD. NT-proBNP value, native T1 relaxation time and longitudinal strain by FT are independent predictors of poor cardiovascular prognosis, thus, their determination would identify high-risk patients who could benefit from a cardiac treatment and follow-up.

Analysis of The Left Atrial Function Using Two-Dimensional Strain in Patients with Recent Diagnosis of Hereditary Hemochromatosis

Hereditary Hemochromatosis (HH) is a genetic condition associated with a systemic iron overload. Heart failure is an important cause of mortality. It has been demonstrated early stages of systolic and diastolic left ventricular dysfunction in previous studies. The aim of the study is to compare the left atrial (LA) function between asymptomatic HH patients and a control group using 2D speckle tracking. Prospective study. LA strain, LA strain rate and LA volumetric parameters during the reservoir, conduit and contraction phases were studied. The LA Stiffness Index was calculated by the ratio between E/e and LA reservoir strain. 30 patients with HH (90% males, 47 ± 18 years old) and 30 healthy controls (85% males, 45 ± 13 years old) were included. LA volume was similar in both groups. No differences were observed in LA ejection fraction (EF), LA passive EF and LA active ejection fraction between both groups. On the contrary, the HH group had lower LA strain during the reservoir (31.5 ± 6.5% vs 38.3 ± 7.9%; P=0.002), and conduit phases (-18 ± 7% vs -23.3 ± 6.4%; P=0.01) and lower LA conduit strain rate (-1.7 ± 0.7 seg^-1 vs -2.1 ± 0.5 seg^-1; P=0.02) than controls. The LA stiffness index was significantly higher in the HH group (0.25 ± 0.9 vs 0.19 ± 0.6; P=0.01) Early abnormalities in the LA function could be detected by using 2D speckle tracking study despite no evidence of changes in atrial size or volumetric parameters.

Magnetic Resonance Myocardial Feature Tracking in Transfusion-Dependent Myelodysplastic Syndrome

BACKGROUND

Myocardial deformation with echocardiography allows early detection of systolic dysfunction and is related to myocardial iron overload (MIO) determined by T2* in hereditary anemias under transfusion support. Our aim was to analyze the diagnostic and prognostic usefulness of magnetic resonance feature tracking (MR-FT) myocardial strain in low-risk myelodysplastic syndromes (LR-MDS) patients.

METHODS

Prospective study in transfusion-dependent LR-MDS patients and healthy controls who underwent a cardiac MR-FT. We analyzed the relationships between strain MR-FT and iron overload parameters and its prognostic impact in cardiovascular events and/or death.

RESULTS

Thirty-one patients and thirteen controls were included. MIO (T2* < 20 ms) was detected in 9.7% of patients. Left ventricular global longitudinal strain (LV-GLS) by MR-FT was pathological (> −19.3%) in 32.3% of patients. Less negative strain values correlated with lower T2* (R = −0.37, p = 0.033) and native myocardial T1 (R = −0.39, p = 0.031) times. LV-GLS by MR-FT was significantly associated with higher incidence of the combined cardiovascular events and/or all-cause death (p = 0.047), with a cut-off value of −17.7% for predicting them (63% sensitivity and 81% specificity, area under the curve = 0.69). After adjusting analysis including demographic, biomarkers and imaging variables, a higher LV-GLS value by MR-FT remained as predictor of combined event in transfusion-dependent LR-MDS patients (hazard ratio, 0.4; confidence interval, 0.15–0.98; p = 0.045).

CONCLUSIONS

Longitudinal myocardial strain by MR-FT in LR-MDS patients is associated to MIO and correlates with adverse events in the follow-up, what could serve as a prognostic tool.

Advancement of echocardiography for surveillance of iron overload cardiomyopathy: comparison to cardiac magnetic resonance imaging

The prevalence of iron overload cardiomyopathy (IOC) is increasing. Patients with transfusion-dependent anemias or conditions associated with increased iron absorption over time are at a significant risk for the development of iron-overloaded states such as IOC. Current guidelines regarding the diagnostic evaluation and follow-up of patients at risk for IOC exist, and are composed of multiple components, including such as echocardiography, genetic testing, magnetic resonance imaging of liver, and cardiac magnetic resonance imaging (CMR). While these are considered reliable for the evaluation of patients at risk for an iron-overloaded state, there is an access challenge associated with initial and serial CMR scanning in this patient population. Furthermore, there are other limiting factors, such as patient characteristics that may preclude the use of CMR as a viable diagnostic imaging modality for these patients. On the other hand, recent evidence in the literature suggests that transthoracic echocardiography, which has had significant technological advances, can equal or even outperform CMR to identify cardiac functional abnormalities such as subclinical left ventricular strain and left atrial functional abnormalities in iron overload conditions. Therefore, there is a potential role of more frequent use of echocardiography for surveillance of the development of IOC. Our purpose with this narrative review is to describe recent advances in echocardiography and propose a potential increased use of echocardiography in the surveillance of the development of IOC.

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.

Cardiovascular magnetic resonance native T2 and T2* quantitative values for cardiomyopathies and heart transplantations: a systematic review and meta-analysis

BACKGROUND

The clinical application of cardiovascular magnetic resonance (CMR) T2 and T2* mapping is currently limited as ranges for healthy and cardiac diseases are poorly defined. In this meta-analysis we aimed to determine the weighted mean of T2 and T2* mapping values in patients with myocardial infarction (MI), heart transplantation, non-ischemic cardiomyopathies (NICM) and hypertension, and the standardized mean difference (SMD) of each population with healthy controls. Additionally, the variation of mapping outcomes between studies was investigated.

METHODS

The PRISMA guidelines were followed after literature searches on PubMed and Embase. Studies reporting CMR T2 or T2* values measured in patients were included. The SMD was calculated using a random effects model and a meta-regression analysis was performed for populations with sufficient published data.

RESULTS

One hundred fifty-four studies, including 13,804 patient and 4392 control measurements, were included. T2 values were higher in patients with MI, heart transplantation, sarcoidosis, systemic lupus erythematosus, amyloidosis, hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) and myocarditis (SMD of 2.17, 1.05, 0.87, 1.39, 1.62, 1.95, 1.90 and 1.33, respectively, P <  0.01) compared with controls. T2 values in iron overload patients (SMD = - 0.54, P = 0.30) and Anderson-Fabry disease patients (SMD = 0.52, P = 0.17) did both not differ from controls. T2* values were lower in patients with MI and iron overload (SMD of - 1.99 and - 2.39, respectively, P <  0.01) compared with controls. T2* values in HCM patients (SMD = - 0.61, P = 0.22), DCM patients (SMD = - 0.54, P = 0.06) and hypertension patients (SMD = - 1.46, P = 0.10) did not differ from controls. Multiple CMR acquisition and patient demographic factors were assessed as significant covariates, thereby influencing the mapping outcomes and causing variation between studies.

CONCLUSIONS

The clinical utility of T2 and T2* mapping to distinguish affected myocardium in patients with cardiomyopathies or heart transplantation from healthy myocardium seemed to be confirmed based on this meta-analysis. Nevertheless, variation of mapping values between studies complicates comparison with external values and therefore require local healthy reference values to clinically interpret quantitative values. Furthermore, disease differentiation seems limited, since changes in T2 and T2* values of most cardiomyopathies are similar.

Free-breathing T2* mapping for MR myocardial iron assessment at 3 T

BACKGROUND

Timely diagnosis of cardiac iron overload is important for children with transfusion-dependent anaemias and requires modern measure methods. Nowadays, myocardial iron quantification is performed by magnetic resonance (MR) breath-hold techniques, sensitive to respiratory motion and unfeasible in patients who are unable to hold their breath. Free-breathing T2* mapping sequences would allow to scan children who cannot hold their breath for a specified duration. Our aim was to test a free-breathing T2* mapping sequence, based on motion correction by multiple signal accumulation technique.

METHODS

We used an electrocardiographically gated T2* mapping sequence based on multiple gradient echo at 3-T in 37 paediatric patients with haematologic disorders aged from 2 to 16. We compared T2* values of myocardium and signal-to-noise ratio of this new sequence with standard breath-holding T2* mapping sequence. T2* values were measured in the interventricular septum for both methods in studies with adequate image quality.

RESULTS

All children were scanned without complications. Five patients were excluded from analysis because of the presence of respiratory artefacts on the T2* images with breath-holding technique due to patient's inability to hold their breath. Breath-holding T2* was 19.5 ± 7.7 ms (mean ± standard deviation), free-breathing T2* was 19.4 ± 7.6 ms, with positive correlation (r = 0.99, R2 = 0.98; p < 0.001). The free-breathing sequence had a higher signal-to-noise ratio (median 212.8, interquartile range 148.5-566.5) than the breath-holding sequence (112.6, 71.1-334.1) (p = 0.03).

CONCLUSION

A free-breathing sequence provided accurate measurement of myocardial T2* values in children.

Prevalence and prognostic impact of left ventricular non-compaction in patients with thalassemia

A high incidence of isolated left ventricular non-compaction (LVNC) has been reported in previous studies on smaller cohorts of patients with thalassemia by cardiac MRI but the clinical impact of the finding is unknown. This prospective cohort study evaluates the prevalence and clinical implication of the finding. Prospective cohort study with enrollment of all consecutive cases with thalassemia referred for cardiac MRI from September 2007 to November 2014. The presence of LVNC was assessed according to the Petersen method and the Jacquier method, with the proposed changes by Fazio, Grothoff, and Chiodi. A clinical follow-up was performed in all patients. We included 560 patients with thalassemia (473 with thalassemia major and 87 with thalassemia intermedia: mean age 31.9 ± 10.6 years, male/female = 250/310). A total number of 1683 MRI tests were performed. A diagnosis of LVNC was determined according to adopted MR criteria in 44 patients (7.9%). Patients with LVNC had a significantly lower ejection fraction (52.68 ± 5.17% vs. 56.90 ± 6.34%; p = 0.0005) and greater indexed LV ESV (48.16 ± 10.03 ml/m² vs. 40.02 ± 10.06 ml/m²; p = 0.0022). After a mean follow-up time was 5.1 years, no significant change of MR parameters was detected as well as no clinical adverse events. LVNC is relatively frequent in patients with thalassemia. However, it is not associated with a worsening of LV function and adverse events after a long-term follow-up.

Cardioprotective Effects of Spirulina Therapy in Children With Beta-Thalassemia Major

INTRODUCTION

Cardiac failure in children with Thalassemia major (TM) is the major cause of death due to iron overload. Spirulina is a micro alga with proven anti-inflammatory, antioxidant and may have a cardioprotective effect.

AIM OF THE WORK

The aim of this study was to evaluate the possible beneficial effect of spirulina supplement in TM children.

SUBJECT AND METHODS

It is an interventional study carried out in 60 children with TM and 30 healthy children matched for age and sex as control. Both groups received spirulina supplement at a dose of 250 mg/kg/d for 3 months. 2D Echo, Tissue Doppler, and speckle tracking imaging (STI) were done for all the studied cohort before and after the 3-month duration of spirulina supplement.

RESULTS

There was significant improvement in hemoglobin level at the end of 3-month period (8.27±1.3 vs. 9.023±1.7; P <0.033) with decrease the frequency of blood transfusion in TM patients (66.6% vs. 40% required transfusion at interval less than 2 wk). Left ventricle global longitudinal strain (LVGLS) significantly improved after 3-month period (-21.7±4.64 vs. -24.67±4.478; P <0.002).

CONCLUSIONS

Spirulina supplement has possible beneficial effect in minimizing the frequency of blood transfusion as well as cardioprotective effect against cardiac damage in TM patients.

Risk factors for heart disease in transfusion-dependent thalassemia: serum ferritin revisited

Heart disease remains a leading cause of morbidity and mortality in transfusion-dependent thalassemia (TDT), which can be attributed to several factors but primarily develops in the setting of iron overload. This was a retrospective cohort study utilizing Webthal^® patient data from five major centers across Italy. Patients without heart disease were followed-up for 10 years (2000-2010) and data were collected for demographics, splenectomy status, serum ferritin and hemoglobin levels, and comorbidities associated with heart disease. Among 379 patients analyzed (mean age 22.9 ± 5.1 years, 47.8% men), 44 (cumulative incidence: 11.6%) developed heart disease during the period of observation. Splenectomy (p = 0.002) and serum ferritin level (p < 0.001) were the only risk factors with significant association with heart disease. A serum ferritin threshold of ≥ 3000 ng/mL was the best predictor for the development of heart disease (86.4% sensitivity and 92.8% specificity, AUC: 0.912, 95% CI 0.852-0.971, p < 0.001). On multivariate analysis, only a serum ferritin level ≥ 3000 ng/mL remained significantly and independently associated with increased risk of heart disease (HR: 44.85, 95% CI 18.85-106.74), with a 5- and 10-year heart disease-free survival of 58 and 39%. The association between iron overload and heart disease in patients with TDT is confirmed, yet a new serum ferritin level of 3000 ng/mL to flag increased risk is suggested.

MRI for Iron Overload in Thalassemia

MRI is a key tool in the current management of patients with thalassemia. Given its capability of assessing iron overload in different organs noninvasively and without contrast, it has significant advantages over other metrics, including serum ferritin. Liver iron concentration can be measured either with relaxometry methods T2*/T2 or signal intensity ratio techniques. Myocardial iron can be assessed in the same examination through T2* imaging. In this review, we focus on showing how MRI evaluates iron in both organs and the clinical applications as well as practical approaches to using this tool by clinicians taking care of patients with thalassemia.