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

The relationship of myocardial and liver T2* values with cardiac function and laboratory findings in transfusion-dependent thalassemia major patients: A retrospective cardiac MRI study

Introduction

Cardiac complications are the leading cause of death in thalassemia patients. It is assumed that progressive iron accumulation results in myocyte damage. Myocardial T2* measurement by cardiac MRI quantifies iron overload. We aimed to study the association between left and right ventricular (LV and RV) function and iron deposition estimation by cardiac MRI T2* in a sample of Iranian patients.

Methods

Cardiac MRI exams of 118 transfusion-dependent thalassemia major patients were evaluated retrospectively. Biventricular function and volume and myocardial and liver T2* values were measured. The demographic and lab data were registered. Poisson and chi-square regression analyses investigated the correlation between the T2* value and ventricular dysfunction.

Results

The study participants' mean (SD) age was 32.7y (9.02), and 47.46% were female. Forty-nine cases (41.52%) revealed at least uni-ventricular dysfunction. LV dysfunction was noted in 20 cases, whereas 47 patients revealed RV dysfunction. The risk of LV dysfunction was 5.3-fold higher in patients with cardiac T2* value less than 10msec (RR=5.3, 95% CI=1.6, 17.1, P<0.05). No association was found between age, liver T2* value, serum ferritin level, and chelation therapy with the risk of LV and RV dysfunction.

Conclusion

Cardiac MRI T2* measure is a good indicator of LV dysfunction. Moreover, MRI parameters, especially RV functional measures, may have a substantial role in patient management. Therefore, cardiac MRI should be included in beta-thalassemia patients' management strategies.

Feature tracking cardiac magnetic resonance imaging to assess cardiac manifestations of systemic diseases

Feature-tracking cardiac magnetic resonance (FT-CMR), with the ability to quantify myocardial deformation, has a unique role in the evaluation of subclinical myocardial abnormalities. This review aimed to evaluate the clinical use of cardiac FT-CMR-based myocardial strain in patients with various systemic diseases with cardiac involvement, such as hypertension, diabetes, cancer-therapy-related toxicities, amyloidosis, systemic scleroderma, myopathies, rheumatoid arthritis, thalassemia major, and coronavirus disease 2019 (COVID-19). We concluded that FT-CMR-derived strain can improve the accuracy of risk stratification and predict cardiac outcomes in patients with systemic diseases prior to symptomatic cardiac dysfunction. Furthermore, FT-CMR is particularly useful for patients with diseases or conditions which are associated with subtle myocardial dysfunction that may not be accurately detected with traditional methods. Compared to patients with cardiovascular diseases, patients with systemic diseases are less likely to undergo regular cardiovascular imaging to detect cardiac defects, whereas cardiac involvement in these patients can lead to major adverse outcomes; hence, the importance of cardiac imaging modalities might be underestimated in this group of patients. In this review, we gathered currently available data on the newly introduced role of FT-CMR in the diagnosis and prognosis of various systemic conditions. Further research is needed to define reference values and establish the role of this sensitive imaging modality, as a robust marker in predicting outcomes across a wide spectrum of patients.

Pulmonary function in patients with transfusion-dependent thalassemia and its associations with iron overload

In patients with transfusion-dependent thalassemia (TDT), pulmonary function impairment has been reported but data are conflicting. Moreover, it remains unclear whether pulmonary dysfunction is associated with iron overload. This study aimed to evaluate the pulmonary function in patients with TDT and to investigate the associations between pulmonary dysfunction and iron overload. It was a retrospective observational study. 101 patients with TDT were recruited for lung function tests. The most recent ferritin levels (pmol/L) and the magnetic resonance imaging (MRI) measurements of the myocardial and liver iron status, as measured by heart and liver T2* relaxation time (millisecond, ms) respectively, were retrieved from the computerized medical records. Only data within 12 months from the lung function measurement were included in the analysis. The serum ferritin, and the cardiac and liver T2* relaxation time were the surrogate indexes of body iron content. The threshold of abnormality in lung function was defined as under 80% of the predicted value. 101 subjects were recruited with a mean age of 25.1 years (standard deviation (SD) 7.9 years). Thirty-eight (38%) and five (5%) demonstrated restrictive and obstructive lung function deficits, respectively. A weak correlation of FVC %Predicted and TLC %Predicted with MRI myocardial T2* relaxation time (rho = 0.32, p = 0.03 and rho = 0.33, p = 0.03 respectively) was observed. By logistic regression, MRI cardiac T2* relaxation time was negatively associated with restrictive lung function deficit (B - 0.06; SE 0.03; Odds ratio 0.94; 95% confidence interval (CI) 0.89-0.99; p = 0.023) after adjusting for age, sex and body mass index. Restrictive pulmonary function deficit was commonly observed in patients with TDT, and the severity potentially correlates with myocardial iron content. Monitoring of lung function in this group of patients, particularly for those with iron overload, is important.

The crucial role of cardiac MRI parameters in the prediction of outcomes in acute clinically suspected myocarditis: A functional and feature-tracking study

Background

The definitive diagnosis of myocarditis is made by endomyocardial biopsy, but it is an invasive method. Recent investigations have proposed that cardiac MRI parameters have both diagnostic and prognostic roles in assessing myocarditis. We aimed to evaluate the role of functional and feature-tracking (FT)-derived strain values in predicting major adverse cardiovascular events (MACE) in patients with acute myocarditis.

Methods and results

We evaluated 133 patients with acute myocarditis (74.4% men) between January 2016 and February 2021. During a mean follow-up of 31 ± 16 months, sixteen patients (12.03%) experienced MACE: three deaths (2.3%), nine ICD implantations (6.76%), and five cardiac transplantations (3.8%). The left ventricular ejection fraction (LVEF), the LV end-diastolic volume index (EDVI), and the LV global longitudinal strain (GLS) were the strongest predictors of MACE. Each 1-unit decline in LVEF and LVGLS or 1-unit rise in LVEDVI resulted in a 5, 24, and 2% increase in MACE, respectively. LVEF ≤36.46% and LVGLS ≤9% indicated MACE with 75% sensitivity and 74.4 and 73.5% specificity, respectively.

Conclusions

In a group of acute myocarditis patients with evidence of myocardial edema and late Gadolinium enhancement, LVEF and GLS were the strongest predictors of adverse cardiac events.