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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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Related in: MedlinePlus

Illustration of the prescription and measurements obtained from phase contrast MR. Two identical stacks of phase contrast images were prescribed on a 3 chamber view of the heart (i). To assess transmitral and aortic flow, a velocity encoding (venc) of 250 cm/s was used and the center of the slice was positioned perpendicular to mitral inflow, at early diastole (ii, upper panel). To assess tissue MR velocities, phase-contrast MR was repeated with a velocity encoding of 30 cm/s, (ii, lower panel) To derive aortic and trans-mitral flow (iii, top panel), circular regions of interest were placed in the aortic (green) and mitral valve (red). On the corresponding mitral flow curve (panel iii, red) the peak mitral velocity of rapid early (E) filling wave late atrial (A) filling wave were recorded. The deceleration time (DT) of the early (E) wave of the mitral valve was computed between the peak of the E wave and the point where the fitted line of descending slope of the E wave reached zero velocity. The isovolumic relaxation time (IVRT) was computed as the delay between the end of the aortic valve flow and the beginning of the transmitral flow. On the tissue velocity images (ii lower panel, regions of interest were placed on the septal (orange) and lateral wall (yellow) and corresponding tissue velocity versus time curves were plotted (iii lower panel). From these curves, peak tissue velocity in early diastole in the septum (e's) and lateral wall (e'l) was measured and average E/e'ratio was computed.
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Figure 2: Illustration of the prescription and measurements obtained from phase contrast MR. Two identical stacks of phase contrast images were prescribed on a 3 chamber view of the heart (i). To assess transmitral and aortic flow, a velocity encoding (venc) of 250 cm/s was used and the center of the slice was positioned perpendicular to mitral inflow, at early diastole (ii, upper panel). To assess tissue MR velocities, phase-contrast MR was repeated with a velocity encoding of 30 cm/s, (ii, lower panel) To derive aortic and trans-mitral flow (iii, top panel), circular regions of interest were placed in the aortic (green) and mitral valve (red). On the corresponding mitral flow curve (panel iii, red) the peak mitral velocity of rapid early (E) filling wave late atrial (A) filling wave were recorded. The deceleration time (DT) of the early (E) wave of the mitral valve was computed between the peak of the E wave and the point where the fitted line of descending slope of the E wave reached zero velocity. The isovolumic relaxation time (IVRT) was computed as the delay between the end of the aortic valve flow and the beginning of the transmitral flow. On the tissue velocity images (ii lower panel, regions of interest were placed on the septal (orange) and lateral wall (yellow) and corresponding tissue velocity versus time curves were plotted (iii lower panel). From these curves, peak tissue velocity in early diastole in the septum (e's) and lateral wall (e'l) was measured and average E/e'ratio was computed.

Mentions: Phase contrast images were analyzed on a dedicated work station (Philips Medical Viewforum release 4.1). A region of interest was placed in the center of the mitral valve and in the aortic valve outflow tract and mean velocity of both regions was plotted over time (Figure 2). LV ejection time (LVET) was computed based on duration of aortic ejection. Isovolumic relaxation time (IVRT) was measured between the end of aortic ejection and the start of mitral filling. Peak early (E) inflow and late atrial (A) velocity were recorded and the E/A ratio were computed. The descending slope of the E wave was plotted and the deceleration time of the E wave (DT) was measured between the peak of the E wave and the point where the fitted line of descending slope of the E wave reached 0 velocity. Peak septal and lateral tissue annular velocity e's and e'l were computed in regions of interest placed in septum and lateral wall on images encoded with a velocity of 30 cm/s. Ratios of mitral E wave to tissue e's and e'l wave velocity were computed as described by Paelinck et al [18].


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 prescription and measurements obtained from phase contrast MR. Two identical stacks of phase contrast images were prescribed on a 3 chamber view of the heart (i). To assess transmitral and aortic flow, a velocity encoding (venc) of 250 cm/s was used and the center of the slice was positioned perpendicular to mitral inflow, at early diastole (ii, upper panel). To assess tissue MR velocities, phase-contrast MR was repeated with a velocity encoding of 30 cm/s, (ii, lower panel) To derive aortic and trans-mitral flow (iii, top panel), circular regions of interest were placed in the aortic (green) and mitral valve (red). On the corresponding mitral flow curve (panel iii, red) the peak mitral velocity of rapid early (E) filling wave late atrial (A) filling wave were recorded. The deceleration time (DT) of the early (E) wave of the mitral valve was computed between the peak of the E wave and the point where the fitted line of descending slope of the E wave reached zero velocity. The isovolumic relaxation time (IVRT) was computed as the delay between the end of the aortic valve flow and the beginning of the transmitral flow. On the tissue velocity images (ii lower panel, regions of interest were placed on the septal (orange) and lateral wall (yellow) and corresponding tissue velocity versus time curves were plotted (iii lower panel). From these curves, peak tissue velocity in early diastole in the septum (e's) and lateral wall (e'l) was measured and average E/e'ratio was computed.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Illustration of the prescription and measurements obtained from phase contrast MR. Two identical stacks of phase contrast images were prescribed on a 3 chamber view of the heart (i). To assess transmitral and aortic flow, a velocity encoding (venc) of 250 cm/s was used and the center of the slice was positioned perpendicular to mitral inflow, at early diastole (ii, upper panel). To assess tissue MR velocities, phase-contrast MR was repeated with a velocity encoding of 30 cm/s, (ii, lower panel) To derive aortic and trans-mitral flow (iii, top panel), circular regions of interest were placed in the aortic (green) and mitral valve (red). On the corresponding mitral flow curve (panel iii, red) the peak mitral velocity of rapid early (E) filling wave late atrial (A) filling wave were recorded. The deceleration time (DT) of the early (E) wave of the mitral valve was computed between the peak of the E wave and the point where the fitted line of descending slope of the E wave reached zero velocity. The isovolumic relaxation time (IVRT) was computed as the delay between the end of the aortic valve flow and the beginning of the transmitral flow. On the tissue velocity images (ii lower panel, regions of interest were placed on the septal (orange) and lateral wall (yellow) and corresponding tissue velocity versus time curves were plotted (iii lower panel). From these curves, peak tissue velocity in early diastole in the septum (e's) and lateral wall (e'l) was measured and average E/e'ratio was computed.
Mentions: Phase contrast images were analyzed on a dedicated work station (Philips Medical Viewforum release 4.1). A region of interest was placed in the center of the mitral valve and in the aortic valve outflow tract and mean velocity of both regions was plotted over time (Figure 2). LV ejection time (LVET) was computed based on duration of aortic ejection. Isovolumic relaxation time (IVRT) was measured between the end of aortic ejection and the start of mitral filling. Peak early (E) inflow and late atrial (A) velocity were recorded and the E/A ratio were computed. The descending slope of the E wave was plotted and the deceleration time of the E wave (DT) was measured between the peak of the E wave and the point where the fitted line of descending slope of the E wave reached 0 velocity. Peak septal and lateral tissue annular velocity e's and e'l were computed in regions of interest placed in septum and lateral wall on images encoded with a velocity of 30 cm/s. Ratios of mitral E wave to tissue e's and e'l wave velocity were computed as described by Paelinck et al [18].

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