A comparison of thigh skeletal muscle volume in heart failure phenotypes assessed by an advanced magnetic resonance imaging sequence
S A Suleman, J M Bilak, A Cowley, S Ayton, S Sze, R B Thompson, J Wormleighton, K S Parke, R England, G P Mccann, I B SquireAbstract
Background
Skeletal muscle (SkM) de-conditioning is a hallmark of Heart Failure (HF) and is linked to increased exercise intolerance and adverse clinical outcomes. While Heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF) represent distinct pathophysiological phenotypes, data comparing SkM volume parameters between phenotypes is limited. Thigh magnetic resonance imaging (MRI) provides a robust surrogate of whole-body SkM composition. Proton density fat fraction imaging and water specific imaging and water specific T1 mapping (PROFIT1) is a novel MRI sequence enabling precise quantification of fat and water signals, allowing accurate quantification of SkM volume. We compared thigh SkM volume between patients with HFpEF and HFrEF using the PROFIT1 sequence.
Methods
ISARC-HF (Imaging assessment of sarcopenia across the HF spectrum) was a cross-sectional single-centre study of patients with HFpEF and HFrEF, diagnosed according to ESC criteria. Thigh SkM (ml/m, indexed to height) was quantified using the PROFIT1 sequence on a 3-Tesla Siemens MAGNETOM VIDA scanner. MRI acquisitions consisted of five transverse slices (slice thickness 3.5 mm) across both quadriceps. Analysis of covariance (ANCOVA) compared indexed thigh SkM volume between groups, adjusted for age, weight, sex and ethnicity. Bonferroni correction was applied for pair-wise comparisons.
Results
MRI data were analysed from 27 HFpEF and 17 HFrEF participants. HFpEF participants had a higher median left ventricular ejection fraction (55 (Interquartile range: 52,60) %), were older (median 76 (68,83) years), more frequently obese (BMI 34.7(29.6, 42.5) kg/m2), predominantly female (44.4%) and included 3 (11%) participants from ethnic minority groups. HFrEF participants had a median ejection fraction of 29 (24, 40) %, were younger (73.5 ± 9.4 years), had lower BMI (28 (25, 31) kg/m2), predominantly male and had no minority ethnic participants. After multivariable adjustments, thigh SkM volume did not differ significantly between HF phenotypes (p=0.871). Adjusted mean muscle volume was 521 ± 38.2 ml/m in HFpEF and 553.3 ± 39.7 ml/m in HFrEF, with an adjusted mean difference of -31.7 ml/m (95% CI -152 to 89.1 ml/m, p = 0.597).
Conclusion
This study is the first to apply the PROFIT1 sequence to directly compare thigh SkM volume between HFrEF and HFpEF. Despite differences in demographics and clinical characteristics, thigh volume did not differ between HF phenotypes after adjustment for key covariates. Our findings suggest that SkM loss may represent a shared systematic feature of HF instead of a phenotype-specific process. This supports a rationale for targeting peripheral SkM dysfunction with unified therapeutic strategies across HF phenotypes.