ACTA1 and miotic rate: However, when utilizing a multivariable linear regression model that incorporates MR dependent variables, we observed that MV tenting area and aVICs (αSMA+) (R2 = 0.53), as well as tenting area and cells undergoing EndMT (CD31+αSMA+) (R2 = 0.58), are significantly associated with MR severity (Figure 4E).