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Iron overload in polytransfused patients without heart failure is associated with subclinical alterations of systolic left ventricular function using cardiovascular magnetic resonance tagging.

Seldrum S, Pierard S, Moniotte S, Vermeylen C, Vancraeynest D, Pasquet A, Vanoverschelde JL, Gerber BL - J Cardiovasc Magn Reson (2011)

Bottom Line: It remains incompletely understood whether patients with transfusion related cardiac iron overload without signs of heart failure exhibit already subclinical alterations of systolic left ventricular (LV) dysfunction.LV ejection fraction, peak filling rate, end-systolic global midventricular systolic Eulerian radial thickening and shortening strains as well as left ventricular rotation and twist, mitral E and A wave velocity, and tissue e' wave and E/e' wave velocity ratio, as well as isovolumic relaxation time and E wave deceleration time were computed and compared to cardiac T2*.Among all parameters, left ventricular twist is affected earliest, and has the highest correlation to log (T2*), suggesting that this parameter might be used to follow systolic left ventricular function in patients with iron overload.

View Article: PubMed Central - HTML - PubMed

Affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Cliniques Universitaires St-Luc and Université Catholique de Louvain, Brussels, Belgium.

ABSTRACT

Background: It remains incompletely understood whether patients with transfusion related cardiac iron overload without signs of heart failure exhibit already subclinical alterations of systolic left ventricular (LV) dysfunction. Therefore we performed a comprehensive evaluation of systolic and diastolic cardiac function in such patients using tagged and phase-contrast CMR.

Methods: 19 patients requiring regular blood transfusions for chronic anemia and 8 healthy volunteers were investigated using cine, tagged, and phase-contrast and T2* CMR. LV ejection fraction, peak filling rate, end-systolic global midventricular systolic Eulerian radial thickening and shortening strains as well as left ventricular rotation and twist, mitral E and A wave velocity, and tissue e' wave and E/e' wave velocity ratio, as well as isovolumic relaxation time and E wave deceleration time were computed and compared to cardiac T2*.

Results: Patients without significant iron overload (T2* > 20 ms, n = 9) had similar parameters of systolic and diastolic function as normal controls, whereas patients with severe iron overload (T2* < 10 ms, n = 5), had significant reduction of LV ejection fraction (54 ± 2% vs. 62 ± 6% and 65 ± 6% respectively p < 0.05), of end-systolic radial thickening (+6 ± 4% vs. +11 ± 2 and +11 ± 4% respectively p < 0.05) and of rotational twist (1.6 ± 0.2 degrees vs. 3.0 ± 1.2 and 3.5 ± 0.7 degrees respectively, p < 0.05) than patients without iron overload (T2* > 20 ms) or normal controls. Patients with moderate iron overload (T2* 10-20 ms, n = 5), had preserved ejection fraction (59 ± 6%, p = NS vs. pts. with T2* > 20 ms and controls), but showed reduced maximal LV rotational twist (1.8 ± 0.4 degrees). The magnitude of reduction of LV twist (r = 0.64, p < 0.001), of LV ejection fraction (r = 0.44, p < 0.001), of peak radial thickening (r = 0.58, p < 0.001) and of systolic (r = 0.50, p < 0.05) and diastolic twist and untwist rate (r = -0.53, p < 0.001) in patients were directly correlated to the logarithm of cardiac T2*.

Conclusion: Multiple transfused patients with normal ejection fraction and without heart failure have subclinical alterations of systolic and diastolic LV function in direct relation to the severity of cardiac iron overload. Among all parameters, left ventricular twist is affected earliest, and has the highest correlation to log (T2*), suggesting that this parameter might be used to follow systolic left ventricular function in patients with iron overload.

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Illustration of the measurements obtained from tagged MR. Consecutive tagged short-axis planes were acquired from apex to base. On each short-axis plane, radial thickening (Err, purple) and circumferential shortening strain (Ecc, blue) were computed and the average of Err and Ecc for the entire left ventricle was recorded. Rotation of the most basal (red) and apical slice (green) slices were computed and left ventricular torsion (orange) was calculated as difference between apical and basal rotation divided by the length (l) between apex and base and multiplied by the mean radius of the base (rbase) and apex (rapex) to obtain LV twist (φ). The first derivate of LV twist over time was respectively systolic twist rate and diastolic untwist rate.
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Figure 1: Illustration of the measurements obtained from tagged MR. Consecutive tagged short-axis planes were acquired from apex to base. On each short-axis plane, radial thickening (Err, purple) and circumferential shortening strain (Ecc, blue) were computed and the average of Err and Ecc for the entire left ventricle was recorded. Rotation of the most basal (red) and apical slice (green) slices were computed and left ventricular torsion (orange) was calculated as difference between apical and basal rotation divided by the length (l) between apex and base and multiplied by the mean radius of the base (rbase) and apex (rapex) to obtain LV twist (φ). The first derivate of LV twist over time was respectively systolic twist rate and diastolic untwist rate.

Mentions: Tagged CMR images were analyzed quantitatively using Harmonic Phase Imaging Analysis (HARP - Diagnosoft, CA) as previously described [20] and as illustrated in Figure 1. End-systolic systolic Eulerian circumferential shortening strain (Ecc) and radial thickening strain (Err) as well as circumferential-radial rotation were computed at the midwall level of each slice. The average of all slices per patients was used as global radial thickening, circumferential shortening strain and rotation. By convention, strains were defined to have a negative sign for shortening (active contraction) and a positive sign for elongation (passive deformation). LV torsion was computed as difference in rotation between the most apical and basal slices. LV twist (φ) was computed as torsion corrected for length: i.e. where ρ is the rotation at the most basal and most apical slice respectively, l is the apex to base length and r is the LV radius at apex and base respectively. Strains were computed in end-systole, determined by the time of aortic valve closure on cine images.


Iron overload in polytransfused patients without heart failure is associated with subclinical alterations of systolic left ventricular function using cardiovascular magnetic resonance tagging.

Seldrum S, Pierard S, Moniotte S, Vermeylen C, Vancraeynest D, Pasquet A, Vanoverschelde JL, Gerber BL - J Cardiovasc Magn Reson (2011)

Illustration of the measurements obtained from tagged MR. Consecutive tagged short-axis planes were acquired from apex to base. On each short-axis plane, radial thickening (Err, purple) and circumferential shortening strain (Ecc, blue) were computed and the average of Err and Ecc for the entire left ventricle was recorded. Rotation of the most basal (red) and apical slice (green) slices were computed and left ventricular torsion (orange) was calculated as difference between apical and basal rotation divided by the length (l) between apex and base and multiplied by the mean radius of the base (rbase) and apex (rapex) to obtain LV twist (φ). The first derivate of LV twist over time was respectively systolic twist rate and diastolic untwist rate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108924&req=5

Figure 1: Illustration of the measurements obtained from tagged MR. Consecutive tagged short-axis planes were acquired from apex to base. On each short-axis plane, radial thickening (Err, purple) and circumferential shortening strain (Ecc, blue) were computed and the average of Err and Ecc for the entire left ventricle was recorded. Rotation of the most basal (red) and apical slice (green) slices were computed and left ventricular torsion (orange) was calculated as difference between apical and basal rotation divided by the length (l) between apex and base and multiplied by the mean radius of the base (rbase) and apex (rapex) to obtain LV twist (φ). The first derivate of LV twist over time was respectively systolic twist rate and diastolic untwist rate.
Mentions: Tagged CMR images were analyzed quantitatively using Harmonic Phase Imaging Analysis (HARP - Diagnosoft, CA) as previously described [20] and as illustrated in Figure 1. End-systolic systolic Eulerian circumferential shortening strain (Ecc) and radial thickening strain (Err) as well as circumferential-radial rotation were computed at the midwall level of each slice. The average of all slices per patients was used as global radial thickening, circumferential shortening strain and rotation. By convention, strains were defined to have a negative sign for shortening (active contraction) and a positive sign for elongation (passive deformation). LV torsion was computed as difference in rotation between the most apical and basal slices. LV twist (φ) was computed as torsion corrected for length: i.e. where ρ is the rotation at the most basal and most apical slice respectively, l is the apex to base length and r is the LV radius at apex and base respectively. Strains were computed in end-systole, determined by the time of aortic valve closure on cine images.

Bottom Line: It remains incompletely understood whether patients with transfusion related cardiac iron overload without signs of heart failure exhibit already subclinical alterations of systolic left ventricular (LV) dysfunction.LV ejection fraction, peak filling rate, end-systolic global midventricular systolic Eulerian radial thickening and shortening strains as well as left ventricular rotation and twist, mitral E and A wave velocity, and tissue e' wave and E/e' wave velocity ratio, as well as isovolumic relaxation time and E wave deceleration time were computed and compared to cardiac T2*.Among all parameters, left ventricular twist is affected earliest, and has the highest correlation to log (T2*), suggesting that this parameter might be used to follow systolic left ventricular function in patients with iron overload.

View Article: PubMed Central - HTML - PubMed

Affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Cliniques Universitaires St-Luc and Université Catholique de Louvain, Brussels, Belgium.

ABSTRACT

Background: It remains incompletely understood whether patients with transfusion related cardiac iron overload without signs of heart failure exhibit already subclinical alterations of systolic left ventricular (LV) dysfunction. Therefore we performed a comprehensive evaluation of systolic and diastolic cardiac function in such patients using tagged and phase-contrast CMR.

Methods: 19 patients requiring regular blood transfusions for chronic anemia and 8 healthy volunteers were investigated using cine, tagged, and phase-contrast and T2* CMR. LV ejection fraction, peak filling rate, end-systolic global midventricular systolic Eulerian radial thickening and shortening strains as well as left ventricular rotation and twist, mitral E and A wave velocity, and tissue e' wave and E/e' wave velocity ratio, as well as isovolumic relaxation time and E wave deceleration time were computed and compared to cardiac T2*.

Results: Patients without significant iron overload (T2* > 20 ms, n = 9) had similar parameters of systolic and diastolic function as normal controls, whereas patients with severe iron overload (T2* < 10 ms, n = 5), had significant reduction of LV ejection fraction (54 ± 2% vs. 62 ± 6% and 65 ± 6% respectively p < 0.05), of end-systolic radial thickening (+6 ± 4% vs. +11 ± 2 and +11 ± 4% respectively p < 0.05) and of rotational twist (1.6 ± 0.2 degrees vs. 3.0 ± 1.2 and 3.5 ± 0.7 degrees respectively, p < 0.05) than patients without iron overload (T2* > 20 ms) or normal controls. Patients with moderate iron overload (T2* 10-20 ms, n = 5), had preserved ejection fraction (59 ± 6%, p = NS vs. pts. with T2* > 20 ms and controls), but showed reduced maximal LV rotational twist (1.8 ± 0.4 degrees). The magnitude of reduction of LV twist (r = 0.64, p < 0.001), of LV ejection fraction (r = 0.44, p < 0.001), of peak radial thickening (r = 0.58, p < 0.001) and of systolic (r = 0.50, p < 0.05) and diastolic twist and untwist rate (r = -0.53, p < 0.001) in patients were directly correlated to the logarithm of cardiac T2*.

Conclusion: Multiple transfused patients with normal ejection fraction and without heart failure have subclinical alterations of systolic and diastolic LV function in direct relation to the severity of cardiac iron overload. Among all parameters, left ventricular twist is affected earliest, and has the highest correlation to log (T2*), suggesting that this parameter might be used to follow systolic left ventricular function in patients with iron overload.

Show MeSH
Related in: MedlinePlus