Beyond late gadolinium enhancement: the key role of diffuse myocardial fibrosis in severe aortic stenosis - an Equilibrium Contrast CMR study

Background In severe aortic stenosis (AS), hemodynamics and conventional indices do not fully explain symptoms, prognosis or treatment response. We hypothesize that diffuse myocardial fibrosis (DMF) is a key missing factor in AS. This can now be accurately measured non-invasively using equilibrium contrast CMR (EQ-CMR) [1] involving a primed gadolinium infusion, T1 measurement preand post-infusion, and direct measure of blood volume of distribution (1-hematocrit). The derived myocardial volume of distribution (Vd(m)) correlates strongly with histological diffuse myocardial fibrosisin AS and this calibration can convert Vd(m) to DMF%. Cell volume can be calculated as 1-DMF%*LV mass.