Predictors of Mortality in Acute Myocardial Infarction Complicated by Cardiogenic Shock despite Intra-Aortic Balloon Pump: Opportunities for Advanced Mechanical Circulatory Support in Asia

Introduction: Acute myocardial infarction complicated by cardiogenic shock (AMI-CS) mortality remains high despite revascularization and the use of the intra-aortic balloon pump (IABP). Advanced mechanical circulatory support (MCS) devices, such as catheter-based ventricular assist devices (cVAD), may impact mortality. We aim to identify predictors of mortality in AMI-CS implanted with IABP and the proportion eligible for advanced MCS in an Asian population. Methods: We retrospectively analyzed a cohort of Society for Cardiovascular Angiography and Intervention (SCAI) stage C and above AMI-CS patients with IABP implanted from 2017–2019. We excluded patients who had IABP implanted for indications other than AMI-CS. Primary outcome was 30-day mortality. Binary logistic regression was used to calculate adjusted odds ratios (aOR) for patient characteristics. Results: Over the 3-year period, 242 patients (mean age 64.1 ± 12.4 years, 88% males) with AMI-CS had IABP implanted. 30-day mortality was 55%. On univariate analysis, cardiac arrest (p < 0.001), inotrope/vasopressor use prior to IABP (p = 0.004) was more common in non-survivors. Non-survivors were less likely to be smokers (p = 0.001), had lower ejection fraction, higher creatinine/ lactate and lower pH (all p < 0.001). On multi-variate analysis, predictors of mortality were cardiac arrest prior to IABP (aOR 4.00, CI 2.28–7.03), inotrope/vasopressor prior to IABP (aOR 2.41, CI 1.18–4.96), lower arterial pH (aOR 0.02, CI 0.00–0.31), higher lactate (aOR 2.42, CI 1.00–1.19), and lower hemoglobin (aOR 0.83, CI 0.71–0.98). Using institutional MCS criteria, 106 patients (44%) would have qualified for advanced MCS. Conclusions: Early mortality in AMI-CS remains high despite IABP. Many patients would have qualified for higher degrees of MCS.