Schematic for the Development of Myocardial Fibrosis in Aortic Stenosis and Response to AVR
As aortic stenosis progresses, left ventricular (LV) mass gradually increases, followed by the development of diffuse fibrosis. Replacement fibrosis occurs later but accelerates rapidly once established. Following relief of pressure-loading conditions after aortic valve replacement (AVR), LV cellular mass and extracellular matrix both regress at different rates. The burden of replacement fibrosis, however, persists. The insets show short-axis cardiac magnetic resonance late gadolinium enhancement imaging slices of a patient with aortic stenosis. At baseline, there is focal late gadolinium enhancement representing discrete focal replacement fibrosis (white arrow). After 1 year, the burden of this replacement fibrosis has increased with the development of several new discrete deposits (red arrows). The patient subsequently underwent AVR. One year later, despite regression of LV mass, there is no regression of replacement fibrosis (white arrows).