Impact of lactate levels on admission in STEMI patients with cardiogenic shock treated with IMPELLA.

The concomitant use of IMPELLA and veno-arterial extracorporeal membrane oxygenation (V-A ECMO) (ECPELLA) has been increasingly used to treat severe cardiogenic shock. However, the relationship between severity of heart failure on admission and prognosis based on differences in the mechanical circulatory support (MCS) is not fully understood. This study evaluated the association between lactate levels on admission and clinical outcomes based on differences in MCS. We identified 852 patients (median age 71 years; 78% male) with cardiogenic shock due to ST-elevation myocardial infarction (STEMI) from the Japanese Registry for Percutaneous Ventricular Assist Devices. The primary endpoint was the in-hospital mortality rate. Additionally, patients were classified into three groups based on lactate levels according to the SCAI SHOCK classification for the assessment of in-hospital mortality: group 1 (lactate level < 2 mmol/L), group 2 (lactate level 2-8 mmol/L), and group 3 (lactate level ≥ 8 mmol/L). The in-hospital mortality rate was 41.8%. The rate of V-A ECMO combined with IMPELLA use was 37.6%. The in-hospital mortality rates of the IMPELLA alone and ECPELLA group were 30.1% and 61.3%, respectively. The median lactate level was significantly higher in non-survivors than in survivors (5.7 mmol/L vs. 3.5 mmol/L, p < 0.0001). The in-hospital mortality rate with IMPELLA alone was significantly higher in group 3 compared to groups 1 and 2; however, there was no difference in in-hospital mortality with ECPELLA among the three groups. A lactate cut-off value of 6.9 mmol/L showed the best discrimination for in-hospital mortality. Patients classified as the SCAI SHOCK stage E have a higher mortality rate with IMPELLA support alone. Further research is needed to optimize management strategies for this high-risk group.