BackgroundAortic stenosis (AS) leads to diffuse fibrosis in the myocardium, which is linked to adverse outcome. Myocardial T1 values change with tissue composition.ObjectiveTo test the hypothesis that our recently developed non-contrast cardiac magnetic resonance (CMR) T1 mapping sequence could identify myocardial fibrosis without contrast agent.Design, setting and patientsA prospective CMR non-contrast T1 mapping study of 109 patients with moderate and severe AS and 33 age- and gender-matched controls.MethodsCMR at 1.5 T, including non-contrast T1 mapping using a shortened modified Look–Locker inversion recovery sequence, was carried out. Biopsy samples for histological assessment of collagen volume fraction (CVF%) were obtained in 19 patients undergoing aortic valve replacement.ResultsThere was a significant correlation between T1 values and CVF% (r=0.65, p=0.002). Mean T1 values were significantly longer in all groups with severe AS (972±33 ms in severe asymptomatic, 1014±38 ms in severe symptomatic) than in normal controls (944±16 ms) (p<0.05). The strongest associations with T1 values were for aortic valve area (r=−0.40, p=0.001) and left ventricular mass index (LVMI) (r=0.36, p=0.008), and these were the only independent predictors on multivariate analysis.ConclusionsNon-contrast T1 values are increased in patients with severe AS and further increase in symptomatic compared with asymptomatic patients. T1 values lengthened with greater LVMI and correlated with the degree of biopsy-quantified fibrosis. This may provide a useful clinical assessment of diffuse myocardial fibrosis in the future.

AimsAngiotensin-converting enzyme (ACE) inhibitors improve left ventricular (LV) remodelling and outcome in heart failure and hypertensive heart disease. They may be similarly beneficial in patients with aortic stenosis (AS), but historical safety concerns have limited their use, and no prospective clinical trials exist.Methods and resultsWe conducted a prospective, randomized, double-blind, placebo-controlled trial in 100 patients with moderate or severe asymptomatic AS to examine the physiological effects of ramipril, particularly LV mass (LVM) regression. Subjects were randomized to ramipril 10 mg daily (n = 50) or placebo (n = 50) for 1 year, and underwent cardiac magnetic resonance, echocardiography, and exercise testing at 0, 6, and 12 months, with follow-up data available in 77 patients. There was a modest but progressive reduction in LVM (the primary end point) in the ramipril group vs. the placebo group (mean change −3.9 vs. +4.5 g, respectively, P = 0.0057). There were also trends towards improvements in myocardial physiology: the ramipril group showed preserved tissue Doppler systolic velocity compared with placebo (+0.0 vs. −0.5 cm/s, P = 0.04), and a slower rate of progression of the AS (valve area 0.0 cm2 in the ramipril group vs. −0.2 cm2 in the placebo arm, P = 0.067). There were no significant differences in major adverse cardiac events.ConclusionACE inhibition leads to a modest, but progressive reduction in LVM in asymptomatic patients with moderate–severe AS compared with placebo, with trends towards improvements in myocardial physiology and slower progression of valvular stenosis. A larger clinical outcome trial to confirm these findings and explore their clinical relevance is required.

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. Methods and 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.