Quick Fire Session
SCMR 22nd Annual Scientific Sessions
Background: In aortic stenosis (AS), the left ventricle (LV) adapts to increased afterload with cellular hypertrophy, extracellular matrix expansion and eventually focal fibrosis. CMR can quantify both focal (by late gadolinium enhancement) and diffuse fibrosis (by T1 mapping). We hypothesized that extracellular volume fraction (ECV%) predicts outcome in patients undergoing aortic valve replacement (RELIEF-AS Study: NCT 02174471).
Patients with symptomatic, severe AS underwent CMR at 1.5T prior to AVR. T1 mapping (MOLLI) was performed prior to and at 15 minutes post-contrast (Dotarem). Global ECV% was analysed from 3 short axis T1 maps excluding segments with infarct-pattern LGE. Indexed extracellular volume (iECV = indexed LV mass * ECV%) was calculated. Mortality data was available for all patients through the UK NHS spine. 10 patients were excluded due to significant bystander valvular (n=3) or myocardial disease (cardiac amyloidosis, n=6; Fabry disease, n=1).
168 patients (age 69±10 years; 56% male; AVAi 0.4±0.1cm2/m2) were included. Management was surgical (n=164) or transcatheter (n=4). At 3-years, 14 patients (8.3%) had died. Baseline ECV% was slightly elevated at 28.4±3.0% (local normal range 27.4±2.8%). Both ECV% and iECV were associated with all-cause mortality (Chi2 7.2, p=0.027; Figure 1 and 2). On multivariate analysis, the factors independently associated with all-cause mortality were left atrial area (HR 1.09, 95%CI 1.03-1.16, p=0.005) and ECV% (HR 1.18, 95%CI 1.003-1.39, p=0.046). No deaths occurred in patients in the lowest iECV tertile (Figure 2). No parameters of LV structure and function, aortic valve severity or comorbidities were independent predictors.
Conclusion: ECV is independently associated with medium-term outcome in patients with severe AS undergoing AVR, and may help identify patients at low risk of post-AVR mortality.