BACKGROUND: The microaxial flow pump (mAFP) has been shown to improve outcomes in selected patients with ST-elevation myocardial infarction (STEMI) and cardiogenic shock (STEMI-CS), but this effect appears to be less evident in women compared with men.

OBJECTIVES: The objective of this secondary analysis of the Danish-German Cardiogenic Shock Trial (DanGer Shock) was to determine sex differences in baseline characteristics, in-hospital course, and the effectiveness of mAFP in STEMI-CS.

METHODS: This was a prespecified sex-specific secondary analysis of the international, multicenter, open-label, randomized DanGer Shock Trial. The primary outcome was 180-day all-cause mortality, analyzed by sex and randomized treatment assignment.

RESULTS: From 2013 to 2023, 355 patients (74 [20.8%] women, 281 [79.2%] men) with STEMI-CS excluding comatose cardiac arrest were enrolled; 179 were randomized to mAFP (37 women) and 176 to standard care (37 women). In an accompanying registry of excluded patients (n = 495), women represented 25.7% (P = 0.10). At baseline, women were significantly older, and time from symptom onset to randomization was 2.2-fold longer in women than in men. Compared with men, women had significantly higher 180-day all-cause mortality (64.9% vs 48.8%; P = 0.015). There was no significant interaction for sex and treatment assignment with respect to 180-day all-cause mortality (P value for interaction = 0.18), yet women (HR: 1.01 [95% CI: 0.58-1.79]) appeared to derive less benefit from mAFP treatment than male patients (HR: 0.66 [95% CI: 0.47-0.93]). This difference was attenuated in patients aged ≤76 years: women (n = 41) HR: 0.66 (95% CI: 0.25-1.76) and men (n = 233) HR: 0.61 (95% CI: 0.40-0.92) (P value for interaction = 0.92). Data from up to 10 years of follow-up support the treatment effect in younger patients, regardless of sex: women HR: 0.45 (95% CI: 0.19-1.09); men HR: 0.57 (95% CI: 0.40-0.82).

CONCLUSIONS: In DanGer Shock, women with STEMI-CS were older and presented later after onset of symptoms, resulting in higher mortality rates. This may have led to the apparent reduced treatment effect in women, but interaction between treatment allocation and sex was not significant, and data showing a benefit of mAFP appeared particularly in younger patients, regardless of sex. As this is a secondary, nonpowered analysis that includes few women, its results must be considered hypothesis generating. (Danish Cardiogenic Shock Trial [DanShock]; NCT01633502).