Table 4: Univariable and multivariable linear regression analysis on risk factors associated with postrepair mitral valve gradients Univariable analysis Multivariable analysis Coefficient Standard error P-value Coefficient Standard error P-value Gender (female) 0.114 0.137 0.40 0.069 0.153 0.65 Age (years) 0.000 0.006 0.98 −0.110 0.005 0.034 Body surface area 0.294 0.302 0.33 0.905 0.340 0.008 Atrial fibrillation −0.137 0.136 0.32 −0.008 0.121 0.95 Posterior mitral annular plication 0.347 0.160 0.030 0.109 0.155 0.48 Annular decalcification −0.682 0.223 0.002 −0.235 0.195 0.23 PMVL resection 0.028 0.139 0.84 0.188 0.126 0.14 PMVL indentation closure −0.154 0.172 0.37 −0.123 0.149 0.41 Annuloplasty ring size −0.164 0.017 <0.001 −0.181 0.018 <0.001 Annuloplasty ring type  Physio I ring 0.486 0.129 <0.001 0.414 0.122 0.001 Postoperative blood haemoglobin value −0.288 0.082 <0.001 −0.301 0.071 <0.001 Postoperative heart rate 0.029 0.004 <0.001 0.024 0.004 <0.001 PMVL: posterior mitral valve leaflet.