Percutaneous mitral valve repair (MVR) using the Evalve MitraClip has been recently introduced as a potential alternative to surgical MVR. To assess immediate haemodynamic changes after percutaneous MVR using right heart catheterisation. Design Single-centre longitudinal cohort study. Tertiary referral centre. Fifty consecutive non-surgical patients (age 74±14 years, EuroSCORE 26±14) with moderate to severe (3+) and severe (4+) mitral regurgitation (MR) due to functional (56%), degenerative (30%) or mixed (14%) disease were selected. MitraClip implantation was performed under general anaesthesia with fluoroscopy and echocardiographic guidance. Haemodynamic variables were obtained before and after MVR using standard right heart catheterisation and oximetry. Haemodynamic changes immediately before and after MVR. Acute procedural success (reduction in MR to grade 2+ or less) was achieved in 46 (92%) patients. Mitral valve clipping reduced mean pulmonary capillary wedge pressure (mPCWP) (from 17±7 to 12±5 mm Hg), PCWP v-wave (from 24±11 to 16±7 mm Hg) and mean pulmonary artery pressure (mPAP) (from 29±12 to 24±6 mm Hg), and increased the cardiac index (CI) (from 3.1±1.0 to 3.9±1.1 l/min/m(2)) (all p<0.05). On Cox univariate regression analysis, mPCWP, PCWP v-wave- and mPAP-changes were associated with death, open-heart surgery for MR and/or hospitalisation for heart failure on follow-up. In a heterogeneous population with predominantly functional MR, percutaneous MVR with the Evalve MitraClip system lowers mPCWP, PCWP v-wave and mPAP by 20%, 20% and 8%, respectively, and increases the CI by 32%.