Fig. 2

Hierarchical model to predict the degree of recurrent mitral regurgitation (MR), with the use of the machine learning algorithm of inferential tree analysis.Interpapillary distance was the best predictor of recurrent MR grade. Only patients with an interpapillary distance > 40 mm developed 3–4 + recurrent MR. In patients with an interpapillary distance ≤ 40 mm, the left ventricle end diastolic diameter was the best predictor of recurrent MR grade. Indeed, only patients with a diameter > 62 mm developed 2 + recurrent MR, and only patients with a diameter ≤ 62 mm had absent to mild recurrent MR