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Jensen PD, Nielsen AH, Simonsen CW, Baandrup UT, Jensen SE, Bøgsted M, Magnusdottir SO, Jensen ABH, Kjaergaard B. In vivo calibration of the T2* cardiovascular magnetic resonance method at 1.5 T for estimation of cardiac iron in a minipig model of transfusional iron overload. J Cardiovasc Magn Reson 2021; 23:27. [PMID: 33691716 PMCID: PMC7948337 DOI: 10.1186/s12968-021-00715-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 01/26/2021] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Non-invasive estimation of the cardiac iron concentration (CIC) by T2* cardiovascular magnetic resonance (CMR) has been validated repeatedly and is in widespread clinical use. However, calibration data are limited, and mostly from post-mortem studies. In the present study, we performed an in vivo calibration in a dextran-iron loaded minipig model. METHODS R2* (= 1/T2*) was assessed in vivo by 1.5 T CMR in the cardiac septum. Chemical CIC was assessed by inductively coupled plasma-optical emission spectroscopy in endomyocardial catheter biopsies (EMBs) from cardiac septum taken during follow up of 11 minipigs on dextran-iron loading, and also in full-wall biopsies from cardiac septum, taken post-mortem in another 16 minipigs, after completed iron loading. RESULTS A strong correlation could be demonstrated between chemical CIC in 55 EMBs and parallel cardiac T2* (Spearman rank correlation coefficient 0.72, P < 0.001). Regression analysis led to [CIC] = (R2* - 17.16)/41.12 for the calibration equation with CIC in mg/g dry weight and R2* in Hz. An even stronger correlation was found, when chemical CIC was measured by full-wall biopsies from cardiac septum, taken immediately after euthanasia, in connection with the last CMR session after finished iron loading (Spearman rank correlation coefficient 0.95 (P < 0.001). Regression analysis led to the calibration equation [CIC] = (R2* - 17.2)/31.8. CONCLUSIONS Calibration of cardiac T2* by EMBs is possible in the minipig model but is less accurate than by full-wall biopsies. Likely explanations are sampling error, variable content of non-iron containing tissue and smaller biopsies, when using catheter biopsies. The results further validate the CMR T2* technique for estimation of cardiac iron in conditions with iron overload and add to the limited calibration data published earlier.
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Affiliation(s)
- Peter Diedrich Jensen
- Department of Hematology, Aalborg University Hospital, PO box 365, 9100, Aalborg, Denmark.
| | | | | | - Ulrik Thorngren Baandrup
- Centre for Clinical Research, North Denmark Regional Hospital, Hjoerring, Aalborg University Hospital, Aalborg, Denmark
| | | | - Martin Bøgsted
- Department of Hematology, Aalborg University Hospital, PO box 365, 9100, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University Hospital, Aalborg, Denmark
| | | | | | - Benedict Kjaergaard
- Biomedical Research Laboratory, Aalborg University Hospital, Aalborg, Denmark
- Department of Cardiothoracic Surgery, Aalborg University Hospital, Aalborg, Denmark
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Consequences of parenteral iron-dextran loading investigated in minipigs. A new model of transfusional iron overload. Blood Cells Mol Dis 2020; 83:102440. [PMID: 32353700 DOI: 10.1016/j.bcmd.2020.102440] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/18/2020] [Accepted: 04/16/2020] [Indexed: 11/21/2022]
Abstract
Patients with blood transfusion-dependent anemias develop transfusional iron overload (TIO), which may cause cardiosiderosis. In patients with an ineffective erythropoiesis, such as thalassemia major, common transfusion regimes aim at suppression of erythropoiesis and of enteral iron loading. Recent data suggest that maintaining residual, ineffective erythropoiesis may protect from cardiosiderosis. We investigated the common consequences of TIO, including cardiosiderosis, in a minipig model of iron overload with normal erythropoiesis. TIO was mimicked by long-term, weekly iron-dextran injections. Iron-dextran loading for around one year induced very high liver iron concentrations, but extrahepatic iron loading, and iron-induced toxicities were mild and did not include fibrosis. Iron deposits were primarily in reticuloendothelial cells, and parenchymal cardiac iron loading was mild. Compared to non-thalassemic patients with TIO, comparable cardiosiderosis in minipigs required about 4-fold greater body iron loads. It is suggested that this resistance against extrahepatic iron loading and toxicity in minipigs may at least in part be explained by a protective effect of the normal erythropoiesis, and additionally by a larger total iron storage capacity of RES than in patients with TIO. Parenteral iron-dextran loading of minipigs is a promising and feasible large-animal model of iron overload, that may mimic TIO in non-thalassemic patients.
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Ebrahim G, Sani Z, Haghjoo M, Armin B. The relationship between the presence of fragmented QRS and iron overload determined by magnetic resonance imaging T2* in patients with beta-thalassemia major. Res Cardiovasc Med 2019. [DOI: 10.4103/rcm.rcm_6_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Di Odoardo LAF, Giuditta M, Cassinerio E, Roghi A, Pedrotti P, Vicenzi M, Sciumbata VM, Cappellini MD, Pierini A. Myocardial deformation in iron overload cardiomyopathy: speckle tracking imaging in a beta-thalassemia major population. Intern Emerg Med 2017; 12:799-809. [PMID: 28456904 DOI: 10.1007/s11739-017-1670-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/24/2017] [Indexed: 12/13/2022]
Abstract
Traditional echocardiography is unable to detect neither the early stages of iron overload cardiomyopathy nor myocardial iron deposition. The aim of the study is to determine myocardial systolic strain indices in thalassemia major (TM), and assess their relationship with T2*, a cardiac magnetic resonance index of the severity of cardiac iron overload. 55 TM cases with recent cardiac magnetic resonance (CMR-T2*) underwent speckle tracking analysis to assess regional myocardial strains and rotation. The results were compared with a normal control group (n = 20), and were subsequently analyzed on the basis of the CMR-T2* values. Two TM groups were studied: TM with significant cardiac iron overload ("low" T2*, ≤20 ms; n = 21), and TM with normal T2* values ("normal" T2*, >20 ms; n = 34). TM patients show significant, uniform decrease in circumferential and radial strain (P < 0.05), and a remarkable reduction in end-systolic rotation, both global, and for all segments (P < 0.001). No significant differences were found between the low- and the normal T2* group either in regional strains and rotation or in standard echocardiographic and CMR parameters. Spearman's correlation coefficient shows no significant correlation between myocardial strains, rotation and cardiac T2* values. In conclusion, our results are in accordance with recent evidence that myocardial iron overload is not the only mechanism underlying iron cardiomyopathy in TM. Strain imaging can predict subclinical myocardial dysfunction irrespective of CMR-T2* values, although it cannot replace CMR-T2* in assessing cardiac iron overload. Finally, it might be useful to appropriately time cardioactive treatment.
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Affiliation(s)
- Luca Antonio Felice Di Odoardo
- Cardiovascular Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, via F. Sforza 35, 20122, Milan, Italy.
| | - Marianna Giuditta
- Cardiovascular Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, via F. Sforza 35, 20122, Milan, Italy
- Rare Diseases Center, Department of Medicine and Medical Specialties, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy
| | - Elena Cassinerio
- Rare Diseases Center, Department of Medicine and Medical Specialties, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy
| | - Alberto Roghi
- Cardiovascular Magnetic Resonance Unit, Department of Cardiology, Niguarda Cà Granda Hospital, P.zza Ospedale Maggiore 3, 20162, Milan, Italy
| | - Patrizia Pedrotti
- Cardiovascular Magnetic Resonance Unit, Department of Cardiology, Niguarda Cà Granda Hospital, P.zza Ospedale Maggiore 3, 20162, Milan, Italy
| | - Marco Vicenzi
- Cardiovascular Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, via F. Sforza 35, 20122, Milan, Italy
| | - Veronica Maria Sciumbata
- Hematology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy
| | - Maria Domenica Cappellini
- Rare Diseases Center, Department of Medicine and Medical Specialties, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy
- Department of Clinical Science and Community Health, Università Degli Studi di Milano, via F. Sforza 35, 20122, Milan, Italy
| | - Alberto Pierini
- Cardiovascular Disease Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, via F. Sforza 35, 20122, Milan, Italy
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De Chiara B, Crivellaro W, Sara R, Ruffini L, Parolini M, Fesslovà V, Carnelli V, Fiorentini C, Parodi O. Early detection of cardiac dysfunction in thalassemic patients by radionuclide angiography and heart rate variability analysis. Eur J Haematol 2005; 74:517-22. [PMID: 15876256 DOI: 10.1111/j.1600-0609.2005.00434.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cardiac dysfunction remains the major cause of death in beta-thalassemia. Aim of this study was to assess early myocardial damage in thalassemic patients with no symptoms or echocardiographic evidence of dysfunction at routine monitoring. METHODS Twenty patients (seven females; median 25 yr [first quartile 22,third quartile 28]) with beta-thalassemia underwent radionuclide angiography (RNA) at rest and during low-dose dobutamine infusion (5-10 gamma/kg/min). Right and left ventricular ejection fractions (EF) were determined by first-pass method and gated equilibrium acquisition, respectively. Twenty-four-hour Holter monitoring with time-domain heart rate variability (HRV) assessment and echocardiographic follow-up (21 months [5,27]) were performed. RESULTS Eleven patients showed regional wall motion abnormalities at RNA; left ventricular EF, HR and diastolic measurements significantly increased after dobutamine infusion. Patients with abnormal RNA right ventricular EF (n = 8, <0.45) showed lower echocardiographic left ventricular EF at the enrollment (0.54 [0.50,0.61] vs. 0.62 [0.56,0.67], P = 0.02) than those with a normal right ventricular EF. Patients with reduced standard deviation of the averages of RR intervals in all 5-minute periods of entire recording (SDANN) (n = 6, <100 ms), a measure of HRV, had lower echocardiographic left ventricular EF (0.53 [0.49,0.62] vs. 0.62 [0.56,0.66], P = 0.03) and lower fractional shortening (0.28 [0.25,0.32] vs. 0.36 [0.30,0.39], P = 0.003) at the enrollment than those with normal SDANN. No significant association was found between RNA and HRV measurements and follow-up left ventricular function. CONCLUSIONS Right ventricular dysfunction and abnormal HRV may represent the early features of cardiac disease in thalassemic patients with no evidence of ventricular dysfunction at routine evaluation.
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Affiliation(s)
- Benedetta De Chiara
- Section of Milan, CNR Clinical Physiology Institute, Niguarda Hospital, Milan, Italy
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