973Aortic valve area, stroke volume, left ventricular hypertrophy, remodeling and fibrosis in aortic stenosis assessed by cardiac MRI. Comparison between high and low gradient, and normal and low flow aortic stenosis

TLDR: Overall accuracy of echocardiographic classification of AS is confirmed, but it is demonstrated that LG/LF and LG/NF AS have larger AVA, less LV hypertrophy and similar focal fibrosis than HG/ LF AS, challenging that view that LG-LF AS is a more advanced state of AS.

Abstract: Background—Recent works using echocardiography suggested that low gradient (LG), low flow (LF) aortic stenosis (AS) has more pronounced LV concentric remodeling, smaller LV cavity size, and more interstitial fibrosis than high gradient (HG) normal flow (NF) AS. Therefore we evaluated the accuracy of echocardiographic measurements, and compared remodeling and fibrosis in different types of AS by cardiac magnetic resonance (CMR). Methods and Results—128 patients (73±11 years, 75 male) with aortic valve area (AVA) <0.6 cm2/m2 and EF>50% by echocardiography, underwent CMR to measure planimetric AVA, phase contrast indexed stroke volume (SVI), LV mass, and focal fibrosis. Using<40 mm Hg, and SVI<35 ml/m2 by echocardiography as criteria for LG and LF respectively, 69(54%) patients were HG/NF, 28(22%) HG/LF, 17(13%) LG/NF, and 14(11%) LG/LF AS. LVOT area, SVI and AVA correlated well between echocardiography and CMR (r=0.7, 0.61, 0.65, respectively; p<0.001 for all). By CMR however, planimetric AVA was larger in LF/LG (0.54±0.08 cm2/m2) and LG/NF (0.61±0.08 cm2/m2) than in HG/LF (0.46±0.07 cm2/m2, p<0.05) AS, and indexed LV mass was lower in LG/LF (75±12 g/m2) and LG/NF (81±18 g/m2) than in HG/LF (100±27 g/m2, p<0.05) AS. All groups of AS had similar LV volumes, predominantly concentric hypertrophy remodeling, and similar amounts of focal fibrosis. Conclusions—CMR confirmed overall accuracy of echocardiographic classification of AS, but demonstrated that LG/LF and LG/NF AS have larger AVA, less LV hypertrophy and similar focal fibrosis than HG/LF AS. This challenges that view that LG/LF AS is a more advanced state of AS.

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ECV measurement. Technical details were: gadoteric acid, 0.1mmol/Kg plus infusion,
multibreath-hold T1 measurement and equilibrium imaging of heart, liver spleen and
biceps muscle at 1.5T (Siemens Avanto). Amyloidosis patients also underwent serum
amyloid P component (SAP) scintigraphy to score liver and spleen involvement by
amyloid.
Results: ECV of the heart, liver, spleen and muscle was significantly elevated in patients
with amyloidosis (0.40, 0.33, 0.42 and 0.12 respectively) compared to healthy controls
(0.25, 0.30, 0.34 and 0.09 respectively) (P , 0.001). Cardiac ECV tracked conventional
measures of systolic and diastolic function. ECV measured in the liver and spleen
tracked increasing organ amyloid burden assessed by SAP scintigraphy (P , 0.001).
Conclusion: Cardiac ECV measures cardiac amyloid burden, but ECV assessment also
be applied to other tissues and organs in the body. Here its use is validated against the
gold standard of SAP scanning in the liver and spleen. ECV measurement may represent
a key technique for measuring ECV increase in systemic diseases.
ORAL ABSTRACTS I | HEART FAILURE | Friday May 24 | 11:42
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11:54
973
Aortic valve area, stroke volume, left ventricular hypertrophy, remodeling and
fibrosis in aortic stenosis assessed by cardiac MRI. Comparison between high
and low gradient, and normal and low flow aortic stenosis
G. Barone-Rochette; S. Pierard; S. Seldrum; CM. de Ravensteen; J. Melchior; F. Maes;
A-C. Pouleur; D. Vancraeynest; A. Pasquet; J-L. Vanoverschelde; B. L Gerber
Valvular Heart Disease Clinic Division of Cardiology, Department of Cardiovascular
Diseases, Cliniques Universitaires St. Luc And Po
ˆ
le de Recherche Cardiovasculaire
(CARD) Institut de Recherche Expe
´
rimentale et Clinique (IREC) Universite
´
Catholique de
Louvain, Brussels, Belgium
Aims: To assess the accuracy of the recently proposed echocardiographic classification
system of aortic stenosis (AS), and to evaluate differences between patients with high
(HG) and low gradient (LG) and normal (NF) and low flow (LF) AS in terms of AS severity,
LV remodeling and fibrosis using cardiovascular magnetic resonance (CMR).
Methods and results: 128 consecutive patients (73+ 11 years, 95 male) with aortic valve
area (AVA) ,0.6 cm/m2 and ejection fraction .50% by echocardiography underwent
evaluation of planimetric AVA, phase contrast indexed stroke volume (SVI), left ventricular
hypertrophy, and focal fibrosis by CMR. Using ,40 mm Hg, and SVI ,35 ml/m2 as criteria
for LG and LF respectively, 69(54%) patients were HG/NF, 28(22%) HG/LF, 17(13%) LG/NF,
and 14(11%) LG/LFAS. Measurements of LVOTarea, SVI and AVA correlated well between
echocardiographyandCMR(r ¼ 0.7,0.61,0.65,respectively;p , 0.001forall). Planimetric
AVA by MRI was less severe in LF/LG (0.54+ 0.08 cm2/m2) and NF/LG (0.61+ 0.08 cm2/
m2) than in HG/LF (0.46+ 0.07 cm2/m2, p , 0.05) AS. Also indexed mass was less in LF/
LG (75+ 12 g/m2) and LG/NF (81+ 18 g/m2) than in HG/LF (100+ 27 g/m2, p , 0.05)
AS. All groups of AS had predominantly concentric hypertrophy remodeling, and similar
amounts of focal fibrosis (1.6+ 3.9%, 1.5? + 2.2%, 0.8 + 0.7% and 1.0 + 1.3% for HG/
NF HG/LF, LG/NF and LG/LF groups respectively p ¼ NS)
Conclusions: CMR confirmed that echocardiographic classification system of AS was
overall accurate. Patients with paradoxical LG/LF and LG/NFAS had less severe ASsever-
ity, less hypertrophy and similar remodeling and similar amount of focal fibrosis than HG/
LF AS.
ORAL ABSTRACTS I | HEART FAILURE | Friday May 24 | 11:54
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12:06
1082
From Tuscan Trabeculae to Florentine Fractals
–
A Novel Approach to
Quantification by CMR
G. Captur; V. Muthurangu; AS. Flett; R. Wilson; A. Barison; S. Anderson; C. Cook
1
;
DM. Sado; WJ. McKenna; TJ. Mohun; PM. Elliott; JC. Moon
1
The Heart Hospital, London, UK;
2
National Institute of Medical Research, UK;
3
Great
Ormond Street Hospital, UK
Background: Several mechanisms have been implicated in abnormal trabecular devel-
opment leading on to left ventricular noncompaction(LVNC). We need a systematic yard-
stick, capable of assessing trabeculae in embryonic mice used in the study of
cardiogenesis and also in human hearts imaged clinically by cardiovascular magnetic
resonance(CMR). Because trabeculae are complex and irregular, a fractal approach for
their quantification would have merit.
Objectives: To: A) Investigate trabecular changes in the embryonic mouse heart using
high resolution episcopic microscopy(HREM) and fractal geometry; B) Apply fractal ana-
lysis to CMR as a means for describing human trabeculae.
Methods: Fractal analysis was performed on embryonic mouse hearts (1500slices,n ¼
12 per stage) starting from the time of cardiac septation till after completion of compaction
(E14.5-18.5). Image processing of HREM data(Fig.1) permitted calculation of the fractal
dimension(FD) for left and right ventricles(LV,RV). The influence of different slicing pla-
nes(0,10,20degrees) on FD was evaluated. A similar technique was developed for use
with human CMR datasets. The analysis was applied to short-axis cine volumetric
studies in 105 healthy volunteers (self-defined white/black) and 30 LVNC cases. Using
an in-house macro, the fractal method was compared to perimetry as another semi-
automated measure of trabecular complexity. Intra-observer(n ¼ 60), inter-observer(n ¼
60) and interstudy reproducibility of fractal analysis(n ¼ 24) was examined. Impact of
varying slice thickness(8,7,6mm;n ¼ 50) on FD was also tested.
Results: In mouse, FD was higher for RV than LV, did not change significantly following a
10degree reslice, and within the LV, FD varied from base to apex and fell with development
(Fig.2)(E14.5 to 18.5,p , 0.0001). Human CMR analysis showed differences between
LVNC and healthy volunteers, especially in the apical third(p , 0.00001;for
LVNC:1.392 + /-0.010)(Fig.3). Maximal apical FD had the highest accuracy in predicting
LVNC. FD showed minimal variability between observers(intra/inter-observer intraclass
correlation coefficient[ICC]:0.97,0.96), between repeat studies(ICC:0.94) and between
slice thicknesses.
Conclusions: These preliminary insights from the fractal characterisation of human and
embryonic murine hearts suggest interesting, previously unquantifiable patterns of tra-
becular complexity. This biological signal could provide a clinically useful and robust
metric for improved trabecular quantification by CMR.
ORAL ABSTRACTS I | HEART FAILURE | Friday May 24 | 12:18
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12:30
986
Prognostic CMR parameters for heart failure and arrhythmias in a large cohort of
well treated thalassemia major patients
A. Pepe
1
; A. Meloni
1
; L. Gulino
1
; G. Rossi
2
; C. Paci
3
; A. Spasisno
4
; P. keilberg
1
; G. Restaino
5
; MC. Resta
6
; V. Positano
1
; M. lombardi
1
1
CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana and Institute of Clinical
Physiology,Pisa,Italy;
2
Epidemiology and Biostatistics Unit, Institute of Clinical Physiology,
CNR, Pisa, Italy;
3
Centro Trasfusionale, Ospedale S. Maria alla Gruccia, Montevarchi, Italy;
4
Unita
`
Microcitemia, A.O.R.N. Cardarelli, Napoli, Italy;
5
Department of Radiology, Catholic
University of the Sacred Heart, Campobasso, Italy;
6
Struttura Complessa di Radiologia,
OSP. SS. Annunziata, Taranto, Italy
Abstracts i3
Eur Heart J Cardiovasc Imaging Abstracts Supplement, May 2013
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