Clinical trial NCT02090699: MR Imaging of Diffuse Myocardial Fibrosis in Transfusion-Dependent Anemias
Official title: Quantification of Diffuse Myocardial Iron Overload Related Interstitial Fibrosis With Cardiac Magnetic Resonance Imaging in Patients With Transfusion-Dependent Anemias
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Thalassemia Major
Chronic Blood Transfusion Related Iron Overload
Keywords: thalassemia major
chronic blood transfusion related iron overload
magnetic resonance imaging
myocardium
fibrosis
Lead sponsor: University Health Network, Toronto
Sponsor class: OTHER
First posted: 2014-03-18
Enrollment: 42
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_CONTROL
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients with transfusion dependent anemias Age-matched healthy subjects

Brief summary: Cardiac failure is the major cause of death in patients with thalassemia and chronic blood transfusion-related iron overload. The treatment of thalassemia has been revolutionized over the past decade with the implementation of cardiac MRI based assessment of iron overload. This has enabled detection of cardiac iron overload prior to symptomatic heart failure and now allows for timely therapy which has resulted in a substantial decrease in mortality. However, currently implemented MR imaging techniques assess for iron content only and not for iron related diffuse fibrosis which play a role in iron related heart failure. Histopathologic studies indicate that patients with iron overload have diffuse interstitial fibrosis. Quantitative MR techniques have shown that patients with various cardiomyopathies demonstrate diffuse myocardial fibrosis and that these changes correlate with changes in cardiac function. The investigators propose that quantitative cardiac MRI for assessment of diffuse myocardial fibrosis can further improve our ability to detect early damage to the myocardium and prevent morbidity and mortality from cardiac iron overload. Detection of fibrosis in patients with thalassemia may allow for earlier identification of cardiomyopathy when compared to other techniques in clinical use including T2\* analysis. Identification of fibrosis could affect patient management as it would allow for tailoring of iron chelation therapy and may lead to better understanding of the disease processes contributing to heart failure and arrhythmia in these patients.

Detailed description: Cardiac failure is the major cause of death in patients with transfusion-related iron overload. Histopathologic studies indicate that patients with myocardial siderosis have diffuse interstitial fibrosis. Cardiac MR assessment of the extracellular volume (ECV) fraction in other disease processes has been shown to accurately characterize diffuse myocardial fibrosis and to correlate with changes in diastolic function. No prior studies have assessed for diffuse interstitial myocardial fibrosis in patients with iron overload utilizing the proposed imaging techniques.

In this study, the investigators will assess the presence and extent of interstitial fibrosis in patients with transfusion-dependent anemias using cardiac MR techniques of T1 mapping and determination of ECV fraction. ECV values will be correlated with the severity of myocardial iron deposition determined by multi-echo T2\*-weighted imaging, systolic ventricular function as determined by cardiac MR and diastolic function assessed by echocardiography. The investigators will recruit 35 patients with transfusion-related iron overload. Ten age-matched healthy subjects will be included as controls, to establish baseline values of myocardial T1 and ECV values. A modified Look-Locker with inversion recovery (MOLLI) sequence will be used to determine T1 values pre-, and post-administration of a gadolinium-based contrast agent (GBCA) at 1.5 Tesla. Calculated ECV values will be compared between iron-overload subjects and healthy controls, and will be correlated with left ventricular ejection fraction, measures of diastolic dysfunction and T2\* values.

Detection of myocardial fibrosis in patients with iron overload would allow for improved prognostication and risk stratification. Elucidation of the relationship between myocardial fibrosis and myocardial iron deposition as well as cardiac functional parameters would provide valuable mechanistic insights and improved pathophysiological understanding of the disease. The results of the proposed study have the potential to significantly impact patient management including recommendations for earlier or more aggressive chelation therapy based on changes in ECV values.

Eligibility criteria: Inclusion Criteria (Patients):

Diagnosis of thalassemia Treatment with iron chelation therapy Referral for cardiac MR assessment of iron overload

Inclusion Criteria (Healthy Volunteers):

No significant past medical history and no evidence of cardiovascular or metabolic disease.

Exclusion Criteria (both groups):

Arrhythmia Claustrophobia Pregnancy and potential pregnancy (patient cannot exclude potential pregnancy) History of allergic reaction to Gadolinium based contrast agent (GBCA) Impaired renal function with eGFR \< 30 ml/min/1.73m2 Any general MR contraindication such as pacemaker or defibrillators.

Primary outcomes:
measure: Evidence of diffuse myocardial fibrosis (elevated extracellular volume fraction) confirmed by MRI
timeFrame: at time of cardiac MR examination for each individual
Secondary outcomes:
measure: Regional myocardial dysfunction as assessed by global longitudinal strain Echocardiography measurement
timeFrame: at time of echocardiography examination for each individual
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: Toronto General Hospital
state: Ontario
Study officials:
References:
citation: Hanneman K, Nguyen ET, Thavendiranathan P, Ward R, Greiser A, Jolly MP, Butany J, Yang IY, Sussman MS, Wintersperger BJ. Quantification of Myocardial Extracellular Volume Fraction with Cardiac MR Imaging in Thalassemia Major. Radiology. 2016 Jun;279(3):720-30. doi: 10.1148/radiol.2015150341. Epub 2015 Dec 10.