Sex-specific Differences in Patients Treated with Venoarterial Extracorporeal Membrane Oxygenation Combined with Microaxial Flow Pump for Left Ventricular Unloading

Background: Women are underrepresented in studies on temporary mechanical circulatory support. Research indicates women may have poorer survival rates and higher risks of complications such as bleeding and limb ischemia compared with men. This study aimed to assess gender disparities in patients treated with veno-arterial extracorporeal membrane oxygenation (va-ECMO) combined with microaxial flow pumps (mAFP) for left ventricular unloading.

Methods: This retrospective single-center analysis included 114 patients (26 females, 88 males) who received va-ECMO and mAFP from January 1, 2018 to December 31, 2022. Propensity score matching (PSM) was used, with statistical significance set at p ≤ 0.05. The primary endpoint was 180-day survival. Secondary endpoints were based on ELSO complication codes.

Results: Baseline characteristics were similar between female and male groups: age (mean: 68.0 versus 63.0 years, p = 0.68), BMI (mean: 24.9 versus 26.3 kg/m², p = 0.53), preoperative lactate levels (mean: 56.0 versus 69.0 mg/dL, p = 0.75), incidence of acute myocardial infarction (19.2% versus 12.5%, p = 0.59), acute on chronic cardiomyopathy (30.8% versus 40.9%, p = 0.48), cardiac arrest (53.8% versus 31.8%, p = 0.07), and VIS (mean: 58.3 versus 35.0, p = 0.10). However, females were significantly less likely to receive full-support mAFP (69.2% versus 90.0%; p = 0.01). For the primary endpoint, females in the unmatched group had worse 180-day survival (15% versus 39%; HR 1.67; p = 0.03). After PSM, survival rates between females and males were not significantly different (16% versus 32%; HR 1.19; p = 0.51). Regarding secondary outcomes, there were no significant differences in rates of hemolysis (45.8% versus 38.6%; OR 1.42; p = 0.50), bleeding (41.7% versus 47.5%; OR 0.91; p = 0.79), neurological issues (8.3% versus 5.1%; OR 2.09; p = 0.47), cardiac complications (12.5% versus 18.6%; OR 0.51; p = 0.37), mechanical complications (4.2% versus 13.6%; OR 0.26; p = 0.18), the need for renal replacement therapy (33.3% versus 22.0%; OR 2.22; p = 0.21), or vascular access–related limb complications (12.5% versus 6.8%; OR 2.14: p = 0.39).

Conclusion: Women were less likely to receive full-support mAFP, and while initial analyses showed worse 180-day survival for females, PSM analysis revealed no significant difference in survival outcomes between sexes.