Impact of Pre-reperfusion Left Ventricle Unloading on ST-segment-elevation Myocardial Infarction According to the Onset-to-Unloading Time

BackgroundImpella in the left ventricle (LV) with delaying reperfusion reduces the infarction size in animal models. However, the onset-to-unloading time in real-world practice can frequently be longer than that in animal experiments. It is unclear whether the impact of pre-reperfusion Impella use is sustained throughout all periods from the onset. This study aimed to evaluate the association between the onset-to-unloading time and the effect of pre-reperfusion Impella on the survival of patients with ST-segment-elevation myocardial infarction (STEMI). MethodsThis study is a post-hoc analysis of the J-PVAD registry. Among all patients registered in J-PVAD between February 2020 and December 2021, patients with STEMI and treated with Impella alone support were selected. Two cohorts were provided based on whether the onset-to-unloading time was less than 6 hours. The patients were divided into two groups according to pre- or post-reperfusion use of Impella in each cohort. The primary outcome was an 80-day survival rate. The independent factors of survival were identified with a multivariable Cox proportional hazard regression analysis after adjusting for the variables that were statistically significant in the univariable analysis. ResultsPatients with pre-reperfusion unloading had a significantly higher 80-day survival rate than patients with post-reperfusion unloading (81.6% vs. 59.5%, p=0.02) in the cohort with an onset-to-unloading time [&ge;]6 hours, while patients with pre- and post-reperfusion unloading had similar 80-day survival rates (85.3% vs. 91.2%, p=0.38) in the cohort with an onset-to-unloading time <6 hours. A multivariable analysis revealed that pre-reperfusion use of Impella was an independent factor of survival (hazard ratio 0.184 [95% confidence interval 0.045-0.746], p=0.02) in the onset-to-unloading time [&ge;]6 hours cohort. ConclusionsPre-reperfusion LV unloading could be a crucial treatment to improve the short-term survival rate when the onset-to-LV unloading was more than 6 hours.