Analysis of the Influencing Factors and Mortality of Early Initiation of Mechanical Circulatory Support in Patients With Acute Myocardial Infarction and Cardiogenic Shock Running title:Influencing Factors of Early Initiation of MCS

Abstract Objective This retrospective study analyzes the influencing factors of early initiation of mechanical circulatory support (MCS) in patients with acute myocardial infarction complicated with cardiogenic shock (AMICS), and compare the mortality rates of various types of mechanical circulatory and different initiation time. Methods From January 2018 to January 2023, 380 AMICS patients hospitalized at Anzhen Hospital meeting the inclusion criteria were enrolled in this retrospective study. Early initiation of MCS was defined as the commencement of mechanical circulatory support before emergency PCI. According to the time of starting MCS, the participants were divided into the pre-emergency PCI MCS implantation group (161 cases) and the post-emergency PCI MCS implantation group (219 cases), and their clinical characteristics and mortality rates were compared. According to the type of MCS, participants were also divided into the combined venoarterial extracorporeal membrane oxygenation (VA-ECMO) and intra-aortic balloon pump (IABP) treatment group (184 cases), the exclusively VA-ECMO treatment group (98 cases), and exclusively IABP treatment group (98 cases) in order to compare their mortality rates. Results Multivariate logistic regression analysis indicated that the total number of white blood cells, arterial lactic acid level, and the use of vasoactive drugs ≥ 2 were the influencing factors for early initiation of mechanical circulatory support, the odds ratio (OR) was 1.071 (P=0.005), 95% CI (1.021, 1.124), 1.319 (P = 0.000), 95% CI (1.195, 1.457), 1.934 (P = 0.033), 95% CI (1.056, 3.541). The arterial lactate level predicts the area under the operating characteristic curve of subjects who start early mechanical circulation support 0.719 (P=0.000), 95% CI (0.667, 0.770), the maximum Youden index was 0.395, and the critical value was 5.05mmol/L. The early initiation of the mechanical circulatory support group had a low mortality rate (21.12%VS43.38%, P=0.000), while the combined VA-ECMO and IABP treatment group had the lowest mortality rate (24.46%VS38.78%VS46.94, P=0.000). Conclusion The number of white blood cells, the level of arterial lactate, and the use of vasoactive drugs ≥ 2 are the influencing factors for the early initiation of mechanical circulatory support in AMICS patients. When the arterial lactic acid level is greater than 5.05mmol/L, mechanical circulatory support should be started as soon as possible. The mortality rate of patients with early mechanical circulatory support was low, and the mortality rate of combined VA-ECMO and IABP treatment was the lowest.