Abstract OBJECTIVES Memo 4D is a semi-rigid ring with an exclusive saddle shape and progressive increased anteroposterior diameter. This preliminary analysis reports 30-day clinical and haemodynamic outcomes of the MANTRA Memo 4D sub-study. METHODS MANTRA is an ‘umbrella’ prospective, multicentre, worldwide post-market study to collect real-life safety and performance data on the Corcym devices. Clinical and echocardiographic outcomes were gathered preoperatively, at discharge and each follow-up. KCCQ-12 questionnaires were collected preoperatively and at 30 days. Echocardiographic studies were performed per a predefined protocol and assessed by an independent core laboratory. RESULTS In total, 166 patients (52, 31.3% female, mean age 60.7 ± 11.4 years) underwent mitral valve repair with Memo 4D in 17 international institutions between July 2021 and June 2023 (enrolment is still ongoing). Primary was the most common aetiology (157, 94.6%), of which 33 cases of Barlow’s disease (19.9%); secondary mitral regurgitation was present in six cases (3.6%). Thirty-day mortality was 0.6% (1). One stroke event (0.6%), one acute kidney failure (0.6%), one myocardial infarction (0.6%) and two reoperations within 30 days were reported. Surgery marked improvement in the patient’s NYHA class associated with a significant increase in KCCQ-12 summary score, from 69.1 (SD = 23.7) preoperatively to 83.9 (SD = 15.7) at 30 days. End-diastolic left ventricular diameters decreased from 55.19 (SD = 7.10) preoperatively to 52.70 (SD = 3.76) mm at 30 days, and left atrial volume decreased from 125.79 (SD = 46.33) preoperatively to 91.51 (SD = 37.20) ml at 30 days. Mitral regurgitation significantly reduced after the operation and up to 30-day follow-up. CONCLUSIONS Mitral valve repair with Memo 4D is associated with good clinical and haemodynamic outcomes in the early period. MANTRA ClinicalTrials.gov number NCT05002543.