title: Myocardial steatosis and left ventricular contractile dysfunction in patients with severe aortic stenosis.
abstract: BACKGROUND
  Aortic stenosis (AS) leads to left ventricular (LV) hypertrophy and dysfunction. We hypothesized that cardiac steatosis is involved in the pathophysiology and also assessed whether it is reversible after aortic valve replacement.
  
  
  RESULTS
  Thirty-nine patients with severe AS (symptomatic=25, asymptomatic=14) with normal LV ejection fraction and no significant coronary artery disease and 20 age- and sex-matched healthy controls underwent cardiac 1H-magnetic resonance spectroscopy and imaging for the determination of steatosis (myocardial triglyceride content) and cardiac function, including circumferential strain (measured by magnetic resonance tagging). Strain was lower in both symptomatic and asymptomatic AS (-16.4 ± 2.5% and -18.1 ± 2.9%, respectively, versus controls -20.7 ± 2.0%, both P<0.05). Myocardial steatosis was found in both symptomatic and asymptomatic patients with AS (0.89 ± 0.42% in symptomatic AS; 0.75 ± 0.36% in asymptomatic AS versus controls 0.45 ± 0.17, both P<0.05). Importantly, multivariable analysis indicated that steatosis was an independent correlate of impaired LV strain. Spectroscopic measurements of myocardial triglyceride content correlated significantly with histological analysis of biopsies obtained during aortic valve replacement. At 8.0 ± 2.1 months after aortic valve replacement, steatosis and strain had recovered toward normal.
  
  
  CONCLUSIONS
  Pronounced myocardial steatosis is present in severe AS, regardless of symptoms, and is independently associated with the degree of LV strain impairment. Myocardial triglyceride content measured by magnetic resonance spectroscopy correlates with histological quantification. Steatosis and strain impairment are reversible after aortic valve replacement. Our findings suggest a novel pathophysiological mechanism in AS, myocardial steatosis, which may be amenable to treatment, thus potentially delaying onset of LV dysfunction.
authors.affiliation: Division of Cardiovascular Medicine, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, United Kingdom.
authors.forename: Masliza
authors.initials: M
authors.lastname: Mahmod
authors.forename: Sacha
authors.initials: S
authors.lastname: Bull
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Suttie
authors.forename: Nikhil
authors.initials: N
authors.lastname: Pal
authors.forename: Cameron
authors.initials: C
authors.lastname: Holloway
authors.forename: Sairia
authors.initials: S
authors.lastname: Dass
authors.forename: Saul G
authors.initials: SG
authors.lastname: Myerson
authors.forename: Jurgen E
authors.initials: JE
authors.lastname: Schneider
authors.forename: Ravi
authors.initials: R
authors.lastname: De Silva
authors.forename: Mario
authors.initials: M
authors.lastname: Petrou
authors.forename: Rana
authors.initials: R
authors.lastname: Sayeed
authors.forename: Stephen
authors.initials: S
authors.lastname: Westaby
authors.forename: Colin
authors.initials: C
authors.lastname: Clelland
authors.forename: Jane M
authors.initials: JM
authors.lastname: Francis
authors.forename: Houman
authors.initials: H
authors.lastname: Ashrafian
authors.forename: Theodoros D
authors.initials: TD
authors.lastname: Karamitsos
authors.forename: Stefan
authors.initials: S
authors.lastname: Neubauer
mesh_terms: D000368:Aged; D001024:Aortic Valve Stenosis / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D001706:Biopsy; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D004452:Echocardiography; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D016014:Linear Models; D019028:Magnetic Resonance Imaging, Cine; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D011237:Predictive Value of Tests; D012307:Risk Factors; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014280:Triglycerides / Q000378:metabolism*; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D016277:Ventricular Function, Left
chemical_list: D014280:Triglycerides
keywords: aortic valve stenosis; cardiac MRI; myocardial steatosis; spectroscopy; strain