Background: Previous studies have demonstrated the benefit of a haemodynamic-guided management strategy with the CardioMEMS™ HF System. No data from French patients have been published.Aims: To analyse the feasibility, safety and clinical benefit of the CardioMEMS™ HF System in 103 French patients included in the CardioMEMS HF System Post-Market Study (COAST).Methods: Prospective open-label cohort of New York Heart Association class III patients with at least one heart failure hospitalization in the 12 months before enrolment, regardless of left ventricular ejection fraction. The primary safety endpoints assessed the freedom from device/system-related complications and from pressure sensor failure at 2 years after implantation. The primary efficacy endpoint was evaluated comparing the rate of heart failure hospitalization during the year before and the year after implantation.Results: At 2 years, there were no device/system-related complications or pressure sensor failures (P < 0.0001). There were 179 heart failure hospitalizations in the year before implantation compared with 79 in the year after implantation (risk reduction 50.3%; rate ratio 0.50, 95% confidence interval 0.38–0.66; P < 0.0001). During the 2 years of follow-up, pulmonary artery pressures were lowered significantly (mean pulmonary artery pressure –3.7 ± 6.3 mmHg; P < 0.0001), with a significant improvement in functional class and quality of life.Conclusions: In the French cohort of the COAST study, we have demonstrated that the CardioMEMS™ HF System is a reliable device, with no device/system-related complications or pressure sensor failures. Patients in this open-label cohort had a significant reduction in pulmonary artery pressures, with an improvement in New York Heart Association classification and quality of life, and a 50% reduction in the heart failure hospitalization rate in the year following implantation compared with the previous year.