Predictors for unfavourable intraprocedural MPG:
We performed a variance analysis using the Kruskal–Wallis test in patients who underwent one-clip implantation to evaluate the impact of clip orientation on intraprocedural MG in patients, who become only one-clip implantation. Central clip implantation (segment A2-P2) was found to induce higher intraprocedural MG (3.58±1.7 mmHg), followed by the technique with cross-clipping (i.e., segment A2-P3, A2-P1; 3.2±1.7 mmHg). Non-central non-cross clip implantation (segment A3-P3; 2.98±1.3 mmHg or A1-P1; 2.66±1.04 mmHg ) led to a lower MG after clipping in our cohort (Supplementary Figure 1) .
Furthermore, we performed an analysis of variance (ANOVA) test to assess the impact of MR aetiology on intraprocedural MG in patients with the one-clip approach. It showed that patients with degenerative or mixed MR had higher intraprocedural MG (Supplementary Figure 2) .
To further evaluate our data for predictors of unfavourable intraprocedural MG, we analysed the anatomical features of the MV. According to linear regression analysis, the AP-diameter had a significant negative correlation with intraprocedural MG in patients who underwent one-clip implantation (r=3.75, 95% CI: 3.57 to 3.94, p<0.001). Thus, patients with smaller annular dimensions (cut off value: 38 mm) had higher intraprocedural MG values. In addition, the leaflet-to-annulus index (LAI) (<1.11) was found to be a strong predictor (AUC: 0.595, 95% CI: 0.542 to 0.647, p=0.0031) for unfavorable intraprocedural MG (>4.5 mmHg) and showed a significant negative correlation with intraprocedural MG values in the regression analysis (OR: 18.43 95% CI: 8.86 to 125.49, p=0.0029). According to the multivariate regression analysis, we found LAI (OR: 9.74, 95% CI: 0.43 to 217.17, p=0.001) to be the strongest, independent predictor for unfavorable intraprocedural MG (≥4.5 mmHg) followed by the count of implanted clips > 2 (OR: 7.54, 95% CI: 1.24 to 87.67, p= 0.01), MG at baseline (OR: 2.06, 95% CI: 1.58 to 2.68, p=0.02) and central clip implantation (OR: 1.87, 95% CI: 0.67 to 3.45, p=0.05) (Figure 4) .