Thalassemia is a genetic disease caused by disruption of globin chain synthesis leading to severe anemia and thus regular blood transfusion is necessary. However, there have been known transfusions-related consequences, including iron overload and multi-organ damage. The aims of this study were to evaluate liver and cardiac function in youth and adult transfusion-dependent Indonesian thalassemic patients and to assess its correlation with serum ferritin levels, as well as T2
Thalassemia is a hereditary disorder caused by disruption of globin chain synthesis leading to reduced level of hemoglobin [
Excess of iron is deposited in vital organs such as heart, liver, spleen, and endocrine organs [
The liver is one of the very susceptible organs commonly affected by iron toxicity. Additionally, cardiac toxicity is the most severe and life-threatening complication of iron overload. Various methods of complications assessment, including serum ferritin level, echocardiography, non-transferrin-bound iron, cardiac T2∗ magnetic resonance imaging (MRI), heart rate variability, liver biopsy, and myocardial biopsy, have been used for early detection of iron overload in thalassemia patients. However, controversial evidence and limitations of their use in clinical practice have been reported. Although T2
Youth and adult TDT patients who regularly visited the outpatient clinics at Department of Internal Medicine, Division of Hematology and Medical Oncology, Hasan Sadikin General Hospital, Bandung, for the past 5 years were invited to join this study. Non-probability convenience sampling was used to recruit the patients. The inclusion criteria were as follows: patients who (1) were older than 14 years old, (2) have received transfusion for at least 2 years, (3) were judged capable of completing the survey physically, and cognitively and (4) were capable of understanding spoken and written Indonesian language. Patients who were on acute and/or severe infection determined by history taking and physical examination were excluded because it will interfere with the results of serum ferritin levels [
Diagnosis of thalassemia was based on the clinical history, molecular diagnosis, and laboratory confirmation. Patients’ data were retrieved from medical record and questionnaire. Demographic variables consisting of age, sex, occupation, and marital status were recorded. Questionnaire was used to obtain more personal information of the patients’ disease, including age at the start of first transfusion and the interval between blood transfusions. Furthermore, the patients’ blood samples were drawn and cardiac examination, including electrocardiography (ECG) and echocardiography, was performed. T2
Hematological parameters were determined by 6 mL of blood, which was collected through venipuncture from each individual using a disposable syringe under sterile conditions, performed by trained laboratory technician. Automated hematology analyzer (Sysmex XN-®Series™ Hematology Analyzers) was used to analyze parameters, including pre-transfusion hemoglobin. Serum ferritin level was also measured by electrochemiluminescence immunoassay (ECLIA) method using ADVIA Centaur XPT Immunoassay System Siemens Healthineers. Although serum ferritin has limitation to predict cardiac iron overload, it can reliably predict siderosis when it is >2500 ng/mL [
The levels of liver enzymes, including aspartate aminotransferase (AST) and alanine aminotransferase (ALT), were used to indicate liver function, as injury to acute or chronic liver eventually results in increase in both serum concentrations. To investigate the enzymes level, the tube containing blood sample was put on room temperature and then centrifuged for 15 minutes at 3,000 rpm for further analysis. The assessment of the enzymes was carried out by using Automated Hematology Analyzer Dimension® EXL™ 200.
ECG and echocardiography to examine cardiovascular function were performed seven days after blood transfusion. Therefore, cardiac alterations found in the assessment could be assumed caused by iron overload and not by anemia. Standard 9-lead ECG was used and the cardiologist analyzed the result. In addition, complete resting two-dimensional and tissue Doppler echocardiography were performed to the patients in the left lateral decubitus position by the same experienced echo cardiographer, by using general electric vivid S6 cardiovascular ultrasound system equipped with 1.5–3.6 MHz Cardiac Section Probe M4S-RS. The diagnostic criteria were according to American Society of Echocardiography [
The T2∗ MRI assessments of subgroup of patients were conducted at the Department of Radiology, Cipto Mangunkusumo National Public Hospital, Jakarta. All cardiac and liver T2∗ images were obtained at 1.5 Tesla MR scanner (Siemens Avanto Germany). Cardiac T2∗ time was obtained from the region of interest at ventricular septum to avoid artifact and liver T2∗ time was obtained from 10 mm slice through the center of the liver and analyzed via computer software [
Data were presented as means ± standard deviation or median (interquartile range) for continuous variables and percentages for categorical variables. Variables were assessed for normality by Kolmogorov-Smirnov or Shapiro-Wilk test. Discrete variables were compared with the chi-square test (Kolmogorov-Smirnov test when appropriate) and continuous variables with one-way analysis of variance (ANOVA) and multiple comparisons with Tukey post hoc test (Kruskal-Wallis test when appropriate). Differences between two groups were analyzed using Student's
Patient characteristics for the total group are given in Table
Patient baseline characteristics for the total sample and stratified by serum ferritin level classification.
Serum ferritin (ng/mL) | |||||
---|---|---|---|---|---|
<2500 ( | 2500–5000 ( | >5000 ( | Total ( | ||
Age, years (mean ± SD) | 22.6 ± 8.9 | 22.6 ± 8.0 | 19.6 ± 3.7 | 21.5 ± 7.2 | 0.275 |
Sex, | 0.592 | ||||
Male | 10 (45.5) | 6 (30.0) | 9 (37.5) | 25 (37.9) | |
Female | 12 (54.5) | 14 (70.0) | 15 (62.5) | 41 (62.1) | |
Age of first transfusion, months (mean ± SD) | 109.2 ± 119.8 | 50.4 ± 61.5 | 23.2 ± 35.7 | 60.1 ± 86.8 | 0.003 |
Transfusion interval, weeks (mean ± SD) | 6.7 ± 10.3 | 6.0 ± 3.1 | 4.3 ± 1.9 | 5.6 ± 6.3 | 0.421 |
Type of chelation therapy, | |||||
Deferoxamine monotherapy | 1 (5.3) | 2 (11.1) | 1 (5.3) | 4 (7.1) | 0.261 |
Deferiprone monotherapy | 11 (57.9) | 7 (38.9) | 5 (26.3) | 23 (41.1) | |
Deferasirox monotherapy | 7 (36.8) | 7 (38.9) | 12 (63.2) | 26 (46.4) | |
Deferoxamine and deferasirox | 0 (0.0) | 2 (11.1) | 1 (5.3) | 3 (5.4) | |
Pre-transfusion Hb, g/dL (mean ± SD) | 6.9 ± 1.2 | 7.3 ± 1.4 | 7.4 ± 2.3 | 7.2 ± 1.7 |
Hb: hemoglobin,
The mean serum ferritin was 4414.5 ± 3165.2 ng/mL. Based on previous study [
Liver enzyme and cardiac function parameters stratified by serum ferritin level classification.
Serum ferritin (ng/mL) | ||||
---|---|---|---|---|
<2500 ( | 2500–5000 ( | >5000 ( | ||
AST | 44.8 ± 21.9 | 54.6 ± 2.0 | 65.3 ± 35.9 | 0.066 |
ALT | 37.5 ± 19.3 | 50.5 ± 25.5 | 60.9 ± 43.6 | 0.051 |
Echocardiography | ||||
LVPWDD (mm) | 9.0 ± 1.9 | 8.8 ± 1.5 | 7.7 ± 1.1 | 0.017 |
LVPWSD (mm) | 13.6 ± 1.8 | 14.8 ± 4.5 | 13.5 ± 2.7 | 0.312 |
LVEDV (mL) | 145.5 ± 14.3 | 96.0 ± 21.5 | 88.8 ± 19.0 | 0.066 |
LVESV (mL) | 36.8 ± 11.5 | 32.8 ± 9.7 | 31.5 ± 10.7 | 0.221 |
LVSV (mL) | 66.4 ± 14.2 | 63.1 ± 13.3 | 57.3 ± 10.2 | 0.054 |
LVEF (%) | 64.7 ± 4.8 | 66.3 ± 4.5 | 65.2 ± 5.2 | 0.552 |
LVFS (%) | 35.4 ± 3.9 | 36.6 ± 3.3 | 35.6 ± 3.9 | 0.580 |
LV diastolic function E/A ratio (m/s) | 1.6 ± 0.4 | 1.6 ± 0.3 | 1.6 ± 0.3 | 0.886 |
LV diastolic function DT (ms) | 168.0 ± 43.3 | 155.5 ± 27.2 | 154.0 ± 25.6 | 0.304 |
LV diastolic function E/E′ | 9.7 ± 2.7 | 13.5 ± 18.5 | 12.4 ± 13.1 | 0.636 |
LV diastolic function IVRT (ms) | 70.5 ± 8.9 | 71.3 ± 5.1 | 64.5 ± 17.2 | 0.262 |
LV diastolic function LAVI (mL/m2) | 33.9 ± 17.3 | 28.2 ± 5.4 | 27.3 ± 6.8 | 0.130 |
Mean PA pressure (mmHg) | 18.6 ± 10.1 | 18.6 ± 8.3 | 20.2 ± 8.5 | 0.799 |
TAPSE (mm) | 24.0 ± 3.8 | 23.4 ± 2.8 | 21.1 ± 2.9 | 0.011 |
Electrocardiography, | 0.958 | |||
Normal | 11 (52.4) | 8 (44.4) | 10 (41.7) | |
Tachycardia | 2 (9.5) | 0 (0.0) | 4 (16.7) | |
T-wave inversion | 3 (14.3) | 10 (55.6) | 7 (29.2) | |
Left ventricular hypertrophy | 2 (9.5) | 0 (0.0) | 2 (8.3) | |
RBBB | 2 (9.5) | 0 (0.0) | 0 (0.0) | |
Arrhythmia | 1 (4.8) | 0 (0.0) | 0 (0.0) | |
Supraventricular extra systole | 0 (0.0) | 0 (0.0) | 1 (4.2) |
The results of liver function test stratified by serum ferritin levels are demonstrated in Table
Liver function stratified by presence of liver siderosis based on T2
T2 | T2 | ||
---|---|---|---|
Age (years), median (IQR) | 23.5 (18.5, 28.5) | 20.0 (18.0, 21.75) | 0.185 |
Serum ferritin (ng/mL), median (IQR) | 1850.45 (563.1, 10363.4) | 4008.0 (2815.8, 5598.5) | 0.245 |
Liver enzymes (ng/mL), median (IQR) | |||
AST | 60.0 (40.0, 80.8) | 39.0 (33.3, 80.0) | 0.509 |
ALT | 55.0 (26.0, 65.3) | 41.5 (29.8, 65.5) | 0.877 |
IQR: interquartile range, AST: aspartate aminotransferase; ALT: alanine aminotransferase.
In terms of correlation analysis, as shown in Figure
Correlation between serum ferritin and liver enzyme. (a) Correlation between serum ferritin and aspartate aminotransferase (AST). (b) Correlation between serum ferritin and alanine aminotransferase (ALT).
Correlation between serum ferritin and T2∗ MRI. (a) Correlation between serum ferritin and cardiac T2∗. (b) Correlation between serum ferritin and liver T2∗.
Table
Cardiac function stratified by presence of cardiac siderosis based on T2
None (T2 | Moderate (T2 | ||
---|---|---|---|
Age, years (mean ± SD) | 20.9 ± 4.0 | 22.5 ± 2.1 | 0.247 |
Serum ferritin, ng/mL (mean ± SD) | 3732.9 ± 2096.8 | 9413.0 ± 5188.7 | 0.060 |
Cardiac T2 | 33.3 ± 9.2 | 11.2 ± 0.7 | 0.022 |
Echocardiography | |||
LVPWDD (mm) | 8.7 ± 1.5 | 7.2 ± 0.0 | 0.059 |
LVSV (mL) | 64.7 ± 11.3 | 48.5 ± 6.4 | 0.067 |
LVEF (%) | 66.2 ± 4.7 | 60.0 ± 2.8 | 0.058 |
LVFS (%) | 36.5 ± 3.5 | 31.5 ± 2.1 | 0.050 |
LV diastolic function E/A ratio (m/s) | 1.7 ± 0.3 | 1.5 ± 0.4 | 0.531 |
LV diastolic function DT (ms) | 159.7 ± 43.3 | 165.0 ± 14.1 | 0.497 |
LV diastolic function E/E′ | 15.9 ± 21.3 | 12.2 ± 4.1 | 0.347 |
LV diastolic function IVRT (ms) | 64.7 ± 17.6 | 74.0 ± 0.0 | 0.348 |
LV diastolic function LAVI (mL/m2) | 29.3 ± 6.6 | 28.1 ± 3.0 | 0.870 |
Mean PA pressure, mmHg | 17.7 ± 8.5 | 27.0 ± 11.3 | 0.154 |
TAPSE, mm | 23.8 ± 3.6 | 17.0 ± 2.8 | 0.040 |
Electrocardiography, | 0.037 | ||
Normal | 12 (60.0) | 0 (0.0) | |
Tachycardia | 0 (0.0) | 1 (50.0) | |
T-wave inversion | 6 (30.0) | 0 (0.0) | |
Left ventricular hypertrophy | 0 (0.0) | 1 (50.0) | |
RBBB | 1 (5.0) | 0 (0.0) | |
Arrhythmia | 1 (5.0) | 0 (0.0) |
LVPWDD: left ventricular posterior wall diastolic diameter; LVPWSD: left ventricular posterior wall systolic diameter; LVEDV: left ventricular end-diastolic volume; LVESV: left ventricular end-systolic volume; LVSV: left ventricular stroke volume; LVEF: left ventricular ejection fraction; LVFS: left ventricular fractional shortening; LV: left ventricle; DT: deceleration time; IVRT: isovolumic (or isovolumetric) relaxation time; LAVI: left atrial volume index; PA: pulmonary artery; TAPSE: tricuspid annular plane systolic excursion; RBBB: right bundle branch block.
With regard to ECG, there were no significant differences in ECG results among the three groups. Most of youth and adult TDT patients have normal ECG findings. T-wave inversion (31.7%) was the most common ECG abnormality, followed by tachycardia (9.5%) and left ventricular hypertrophy (6.3%). After being stratified by presence of cardiac siderosis based on T2∗ MRI findings, there was significant difference on ECG changes in TDT patients as shown in Table
Serum ferritin remains an inexpensive and easily available tool for assessment of iron overload regardless of its limitation, but T2∗ MRI still becomes a recommended strategy to evaluate iron overload [
In this study, age of the first blood transfusion was found significantly associated with serum ferritin levels. The earlier the age at the start of blood transfusion, the higher the serum ferritin levels. Mishra and Tiwari [
In our study, most of patients were given deferasirox followed by deferiprone as their iron chelation therapy. It is known that deferasirox and deferiprone offer an important treatment option for people with thalassemia and secondary iron overload [
Our study demonstrated higher AST and ALT levels occurred with increased serum ferritin concentration. In line with this, Al-Moshary et al. [
Cardiac dysfunction secondary to iron overload in thalassemia patients may start early in life although clinical signs are not observed in most patients [
ECG abnormalities reported in thalassemia patients have been documented in previous studies [
In this study, LVPWDD had relationship with serum ferritin levels. It may imply that diastolic dysfunction may occur with the increased of serum ferritin, reflecting an alteration in diastolic property most probably caused by iron accumulation in the heart. Based on natural history, diastolic dysfunction generally appears before systolic dysfunction [
In terms of ventricular systolic function evaluation, decreased LVSV in patients with higher serum ferritin levels suggested some degree of left ventricular dysfunction. In study by Rodrigues et al. [
There were some limitations in this study. This was a cross-sectional study, which does not allow for the inference of cause and effect relationship. Furthermore, a greater number of subjects are necessary in any further study. Although T2∗ MRI is the best way to quantify iron accumulation, the low cost and widespread availability of serum ferritin make its use necessary [
In conclusion, our results indicated that serum ferritin level and T2∗ MRI value in youth and adult TDT patients have relationships with liver and cardiac function. It is necessary to re-evaluate the chelation therapy in patients with higher serum ferritin levels, including the compliance to chelation therapy. In addition, access of T2∗ MRI should be provided in area with high prevalence of TDT. Based on these findings, it is important to routinely monitor any possible complications, including liver and cardiac damage in youth and adult patients with TDT. Early detection and therefore timely treatment of such complications could improve the quality of life of these patients.
The data used to support the findings of this study are available from the corresponding author upon request.
This study protocol was approved by the Ethics Committee of Faculty of Medicine, Universitas Padjadjaran, Bandung (institutional review board approval number 662/UN6.C10/PN/2017), and conducted in accordance with the Declaration of Helsinki.
The authors have no financial conflicts of interest to disclose concerning the manuscript.
The authors express great appreciation to the members of the Thalassemia Parents Association for their cooperation in this investigation. This study was financially supported by Internal Research Grant of Universitas Padjadjaran and Academic Leadership Grant (ALG) for Thalassemia Study.