The Association between Serum Ferritin Level, Tissue Doppler Echocardiography, Cardiac T2* MRI, and Heart Rate Recovery in Patients with Beta Thalassemia Major

Ferritin thresholds for cardiac and liver hemosiderosis in β-thalassemia patients: a diagnostic accuracy study

Ferritin is frequently used to screen some dire consequences of iron overload in β-thalassemia patients. The study aimed to define the best cutoff point of ferritin to screen for cardiac and liver hemosiderosis in these cases. This was a registry-based study on β-thalassemia patients living throughout Mazandaran province, Iran (n = 1959). In this diagnostic research, the index test was ferritin levels measured by a chemiluminescent immunoassay. As a reference test, T2*-weighted magnetic resonance imaging (T2*-weighted MRI) was applied to determine cardiac and liver hemosiderosis. A cutoff point of 2027 ng/mL for ferritin showed a sensitivity of 50%, specificity 77.4%, PPV 42.1%, and NPV 82.5% for cardiac hemosiderosis (area under curve [AUC] 0.66, 95% CI 0.60-0.71, adjusted odds ratio [OR] 2.05, 95% CI 1.05-4.01). At an optimum cutoff point of 1090 ng/mL, sensitivity 66.7%, specificity 68%, PPV 82.9%, and NPV 46.8% for liver hemosiderosis were estimated (AUC 0.68, 95% CI 0.63-0.73, adjusted OR 3.93, 95% CI 2.02-7.64. The likelihood of cardiac hemosiderosis serum ferritin levels below 2027 ng/mL is 17.5%. Moreover, 82.9% of β-thalassemia patients with serum ferritin levels above 1090 ng/mL may suffer from liver hemosiderosis, regardless of the grades.

Cardiopulmonary testing in adult patients with β-thalassemia major in comparison to healthy subjects

β-Thalassemia patients often have a reduced capacity of exercise and abnormal respiratory function parameters, but the reasons are unclear. In order to identify the causes of the exercise limitation, we performed a cardiopulmonary exercise testing (CPET) in a group of 54 adult β-thalassemia major (TM) patients without pulmonary arterial hypertension and in a group of healthy control subjects. All subjects underwent cardiac echocardiography and carried out pulmonary function tests. TM patients also filled an IPAQ questionnaire on usual physical activity (PA).Overall, TM patients have a diminished exercise performance in comparison to control subjects. In fact, peak oxygen uptake (V'O₂ peak), expressing maximum exercise capacity, was decreased in 81.5% of the patients; similarly, anaerobic threshold (V'O₂@AT) and O₂ pulse also resulted lowered. In multivariable regression models adjusted for gender, age, BMI, and mean haemoglobin, V'O₂ peak and O₂ pulse were positively associated with cardiac iron overload (T2*). No ventilatory limitation to exercise was observed. The most important causes of exercise limitation in these patients were muscular deconditioning and reduced cardiac inotropism due to iron deposition. Only 15/54 (27.8%) TM patients used to perform vigorous physical activity. These results suggest that a program of regular physical activity may be useful to increase the tolerance to effort and therefore to improve the quality of life in these patients.

Evaluation of electrocardiography, echocardiography and cardiac T2* for cardiac complications in beta thalassemia major

Cardiac complications such as heart failure and arrhythmias caused by "iron-induced" cardiomyopathy are considered as the primary cause of death in the patients with β-thalassemia major. The aim of this study was to evaluate electrocardiography, echocardiography according cardiac T2* and ferritin findings of patients followed-up for β-thalassemia major, and to investigate the importance of these findings for early detection of cardiac complications. The study included 41 patients and 25 healthy individuals with matched age and gender. The cardiac T2* results revealed a cardiac iron load below 20 ms in 12 (29.27%) patients, and above 20 ms in 29 (70.73%) patients. All electrocardiography parameters significantly increased in the patient group when compared to the control group (p < 0.05). All parameters except P wave segment in electrocardiography and T peak-end/QT ratio were significantly higher in the group with cardiac T2* < 20 ms than the group with cardiac T2* > 20 ms (p < 0.05). Intraventricular septum thickness, left ventricular posterior wall thickness, left ventricular mass and left ventricular mass index detected by echocardiography were significantly higher in the group with T2* < 20 ms (p < 0.05). Electrocardiography, echocardiography, cardiac T2* and ferritin findings should be carefully evaluated in these patients in order to detect early signs of cardiac complications.

Evaluation of iron overload by cardiac and liver T2* in β-thalassemia: Correlation with serum ferritin, heart function and liver enzymes

Introduction: In this study, we aimed to assess the relationship of cardiac and hepatic T2* magnetic resonance imaging (MRI) values as a gold standard for detecting iron overload with serum ferritin level, heart function, and liver enzymes as alternative diagnostic methods. Methods: A total 58 patients with beta-thalassemia major who were all transfusion dependent were evaluated for the study. T2* MRI of heart and liver, echocardiography, serum ferritin level, and liver enzymes measurement were performed. The relationship between T2* MRI findings and other assessments were examined. Cardiac and hepatic T2* findings were categorized as normal, mild, moderate, and severe iron overload. Results: 22% and 11% of the patients were suffering from severe iron overload in heart and liver, respectively. The echocardiographic findings were not significantly different among different iron load categories in heart or liver. ALT level was significantly higher in patient with severe iron overload than those with normal iron load in heart (P =0.005). Also, AST level was significantly lower in normal iron load group than mild, moderate, and severe iron load groups in liver (P <0.05). The serum ferritin level was significantly inversely correlated with cardiac T2* values (r = -0.34, P =0.035) and hepatic T2* values (r = -0.52, P =0.001). Conclusion: Cardiac and hepatic T2* MRI indicated significant correlation with serum ferritin level.

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.

Effective method of evaluating myocardial iron concentration in pediatric patients with thalassemia major

Background

The use of T2* magnetic resonance imaging (MRI) has been promoted by recent studies as a noninvasive method for the detection of iron overload in thalassemia major patients. This study aims to estimate the iron load in the heart and liver of thalassemia major patients using T2* MRI and to determine its correlation with the left ventricle ejection fraction and serum ferritin level.

Methods

Forty β-Thalassemia major patients were included in the study. We evaluated the serum ferritin level, echocardiography, cardiac T2*, myocardial iron concentration (MIC), liver iron concentration (LIC) and hepatic T2* in all patients. CMR T2* findings were categorized as normal cardiac T2* (T2* >20 ms) or abnormal cardiac T2* (T2* <20 ms).

Results

The study found that 85% of patients had a normal cardiac T2* value. The median serum ferritin level was 2189. A significant inverse correlation was found between the serum ferritin level and the cardiac T2* (r=−0.381, =0.015); however, the correlations between serum ferritin and the hepatic T2* and liver iron concentration were statistically non-significant (P=0.539 and P=0.637, respectively). Additionally, the LVEF correlation was statistically non-significant with SF, hepatic T2* and cardiac T2*.

Conclusion

Regardless of the serum ferritin level or left ventricle function, a cardiac T2* MRI should be done for all patients with β-Thalassemia major in order to estimate the myocardial iron concentration.

Impact of Genotype of Beta Globin Gene on Hepatic and Myocardial Iron Content in Egyptian Patients with Beta Thalassemia

Iron overload causes most of the mortality and morbidity associated with thalassemia. Excess iron deposits primarily in the liver, but once a threshold level is reached, iron loading may occur in other tissues such as the heart. Magnetic resonance imaging is a well established technique to noninvasively quantify myocardial and liver iron content. More than 300 disease-causing mutations have been identified. We aimed to determine the impact of genotype on liver iron content in patients with beta thalassemia. Cross sectional study was carried on 73 patients with beta thalassemia. MRI liver and heart was performed to determine hepatic and myocardial iron overload. Genotyping was determined by DNA sequencing technique. The mean liver iron content was 17.4 mg/g dw and mean cardiac T2* was 25.5 ms in our patients. Patients with β⁰β⁰ were associated with significantly higher liver and myocardial iron content compared to those with β⁰β⁺ and β⁺β⁺ genotypes. There was a clear association between genotype and both hepatic and myocardial iron overload. Patients with β⁰β⁰ had significantly higher liver and heart iron content compared to those with β⁰β⁺ and β⁺β⁺ genotypes. Liver iron content was strongly correlated to serum ferritin levels and myocardial iron overload.

Cardiac MRI T2* in Liver Transplant Candidates: Application and Performance of a Novel Imaging Technique to Identify Patients at Risk for Poor Posttransplant Cardiac Outcomes

Background

In end-stage liver disease, alterations in iron metabolism can lead to iron overload and development of iron overload cardiomyopathy. In liver transplant candidates, evaluation for cardiac iron overload and dysfunction can help to identify candidates at increased risk for peritransplant morbidity and mortality, though recommendations for pretransplant evaluation of cardiac iron overload are not standardized. Cardiac Magnetic Resonance Imaging T2* (CMRI-T2*) is a validated method to quantify cardiac iron deposition, with normal T2* value of 20 ms or greater. In this study, we sought to identify the incidence and predictors of iron overload by CMRI-T2* and to evaluate the impact of cardiac and iron overload on morbidity and mortality after liver transplantation.

Methods

In this retrospective single-center cohort study, all liver transplant candidates who underwent a pretransplant CMRI-T2* between January 1, 2008, and June 30, 2016, were included to analyze the association between clinical characteristics and low T2* using logistic regression.

Results

One hundred seventy-nine liver transplant candidates who received CMRI-T2* were included. Median age was 57 years, 73.2% were male, and 47.6% were white. 49.7% had hepatitis C and 2.8% had hemochromatosis. Median Model for End-Stage Liver Disease score was 25. 65.2% were Child-Pugh C. In multivariable logistic regression, T2* less than 20 ms (n = 35) was associated with Model for End-Stage Liver Disease score of 25 or greater (odds ratio [OR], 3.65; P = 0.007), Child-Pugh C (OR, 3.42; P = 0.03), and echocardiographic systolic ejection fraction less than 65% (OR, 2.24; P = 0.01). Posttransplant heart failure occurred exclusively in recipients with T2* less than 15 ms. Survival was worse in T2* 10 to 14.9 versus T2* of 20 ms or greater (hazard ratio, 3.85; P = 0.003), but not for 15 to 19.9 versus T2* of 20 ms or greater.

Conclusions

Severity of liver disease and systolic dysfunction is associated with T2* less than 20 ms, though there was no difference in posttransplant outcomes between T2* 15 to 19.9 and T2* 20 ms or greater, suggesting that individuals with T2* of 15 ms or greater may be suitable transplant candidates. CMRI-T2* is an additional diagnostic tool in evaluating transplant candidates at high risk for posttransplant cardiac complications.

Heart Rate Recovery as a Novel Test for Predicting Cardiac Involvement in Beta-Thalassemia Major

BACKGROUND

Abnormal heart rate recovery (HRR) is predictive of cardiac mortality. Autonomic abnormalities in beta-thalassemia major (TM) patients have been reported in previous studies. However, the importance of low HRR in exercise stress test in TM patients has not yet been ascertained. Therefore, this study will be the first of its kind in the literature.

METHODS

Exercise stress test was performed on 56 TM patients who were being treated at the Thalassemia Center of our hospital, along with 46 non-TM iron deficiency anemia (IDA) patients as a control group. Values for HHR were recorded at 1, 2, 3, 4 and 5 min, and HRR was calculated by the difference of heart rate at peak exercise and at a specific time interval following the onset of recovery.

RESULTS

All HRR values were found to be lower in TM patients compared to those in the IDA group. Exercise capacity [metabolic equivalents (METs)] was also found to be low in these patients (p < 0.001) as well. Total exercise time was significantly lower in the TM group compared to the IDA group (8.40 ± 1.7 min vs. 11.17 ± 1.51 min, p < 0.001). Exercise capacity (METs) was also lower in the TM group compared to the IDA group. Mean T2* value was 28.3 ± 13.7 ms in TM patients on magnetic resonance imaging (MRI). In addition, there are 18 TM patients with T2* value was < 20 ms.

CONCLUSIONS

This study found that TM was independently associated with low HRR. Such a condition is an indicator of autonomic dysfunction in TM patients, since abnormal HRR is related to impaired autonomic response. In addition, impaired HRR may be a marker of early cardiac involvement in patients, whose T2* value is high on MRI. Modifying HRR with a cardiac rehabilitation program in TM patients with impaired HRR is a field open for further investigation.