Funding Acknowledgements Type of funding sources: None. Backgroud Ventricular septal defect (VSD), is a rare but fatal complication of myocardial infarction (MI) associated with high early mortality. Temporary mechanical circulatory support (t-MCS) of any type can be used to stabilize the patient as a bridge to surgical or percutaneous closure, or to heart transplantation or long-term ventricular assist device, but with a low level of evidence. The Impella® device is a trans-valvular aortic axial pump inserted surgically or percutaneously which pumps blood directly from the left ventricle into above the aortic valve. Its hemodynamic effects seem interesting, explaining its use by certain expert centers in this context, but the data in this indication are rare in the literature. Method It was an European retrospective multicentre registry of patients hospitalized for ischemic VSD managed with an Impella® (2.5, CP or 5.0) over the past 10 years (2010 to 2021). The primary endpoint was in-hospital mortality. The secondary endpoints were the monitoring of clinical, hemodynamic and biological data at 24 hours, the medications and organ supports used during hospitalization, intra-hospital complications and mortality at 6 months and 1 year. Results On 20 centers contacted, 17 responded (85%). A total of 28 patients managed with an Impella® device for an ischemic VSD in 7 European center were included (41% of respondents). All patients included were in cardiogenic shock (100%, n=28) with multiple organ failure (SAPSII 41 [IQR 53-27], Euroscore 57 [IQR 75-23] and arterial lactate 6 +/-5 mmol). The majority of patients required inotropic and vasopressor support (dobutamine 55% and norepinephrine 96%). In-hospital and 1-year mortalities were 75%. Surgical closure of the VSD was performed in 36% of patients, percutaneous closure in 21% and medical treatment alone for 43, with in-hospital mortality of 30, 92 and 100% respectively. Hospital mortality also seemed to be associated with the type of t-MCS used (71% for Impella alone, 67% for Impella® with IABP combination and 78% for Impella® with ECLS combination). Survivors were more likely to have benefited from CABG revascularization (p < 0.011). Conclusion Despite the potential hemodynamic advantages, the use of Impella® in patients with ischemic VSD is associated with high mortality which may be partly related to its exclusive use in the most severe cardiogenic shock patients, to associated therapies in particular the type of closure of the VSD, or the complications of the device itself.