Whether age impacts the recently demonstrated survival benefit of microaxial flow pump (mAFP) treatment in patients with ST-segment elevation myocardial infarction (STEMI) and cardiogenic shock (CS) is unknown.The purpose of this study was to assess the impact of age on mortality and complication rates in patients with STEMI-related CS randomized to standard care or mAFP on top of standard care.This is a secondary analysis of the Danish-German Cardiogenic Shock (DanGer Shock) trial, an international, multicenter, open-label trial, in which 355 adult patients with STEMI-related CS were randomized to receive an mAFP (Impella CP) plus standard care or standard care alone. The primary outcome of 180-day all-cause mortality is analyzed according to age and intervention.From lowest to highest age quartile, the median ages (range) were 54 years (Q1-Q3: 31-59 years), 65 years (Q1-Q3: 60-69 years), 73 years (Q1-Q3: 70-76 years), and 81 years (Q1-Q3: 77-92 years). There were no differences in blood pressure, lactate level, left ventricular ejection fraction, or shock severity at randomization across age groups. Mortality increased from lowest to highest quartile (31%, 47%, 61%, and 73%, respectively; log-rank P < 0.001), with an adjusted OR for death at 180 days of 7.85 (95% CI: 3.37-19.2; P < 0.001) in the highest quartile compared to the lowest. The predicted risk of mortality was higher in the standard-care group until approximately 77 years, after which the predicted risk became higher in the mAFP group (P = 0.20). In patients <77 years, a reduced 180-day mortality was observed in patients randomized to the mAFP (OR: 0.45; 95% CI: 0.28-0.73; P = 0.001), opposed to patients aged ≥77 years (OR: 1.52; 95% CI: 0.57-4.08; P = 0.40), P for interaction = 0.028. Complications were more frequent in the mAFP group, but there were no apparent differences in incidence of complications across all ages.This exploratory secondary analysis of the DanGer Shock trial demonstrates that older patients with STEMI-related CS experience high mortality and may not attain the same benefit from routine treatment with an mAFP as younger patients. Incorporating age as a factor in patient selection may enhance the overall benefit of this therapy. (Danish Cardiogenic Shock Trial [DanShock]; NCT01633502).