Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) is used to support refractory cardiogenic shock (CS) but may increase peripheral afterload. Invasive hemodynamic measurement and cardiopulmonary congestion during VA ECMO may correlate with survival, but the precise mechanisms underlying this benefit are uncertain.

The aim of this study was to determine whether invasive hemodynamic monitoring with a pulmonary arterial catheter (PAC) and early on-support pulmonary artery diastolic pressure (PAD) are associated with survival during VA ECMO.

Adult patients with CS from the ELSO (Extracorporeal Life Support Organization) Registry from 2015 to 2020 were analyzed. Invasive hemodynamic status was assessed at 24 hours of ECMO. The primary outcome was 30-day in-hospital mortality. The association between the use of left ventricular mechanical unloading (LVMU) and both 24-hour on-support invasive hemodynamic status and in-hospital mortality was examined using landmark adjustment.

In total, 7,654 patients treated with VA ECMO for CS were identified, of whom 3,077 were managed with PACs. PAC use during VA ECMO was not significantly associated with lower in-hospital mortality, with an adjusted OR of death of 0.95 (95% CI: 0.897-1.006; P = 0.077). Among patients who survived 24 hours, higher single early values of on-support PAD at 24 hours (>18 mm Hg) were associated with greater in-hospital mortality within 30 days (HR: 1.29; 95% CI: 1.13-1.46; P < 0.001), which remained consistent within subgroups receiving concomitant LVMU (peripherally inserted ventricular assist device or intra-aortic balloon pump).

There is a significant, graded relationship between higher single measures of 24-hour on-support PAD and death. Patient survival is greatest when 24-hour PAD is <18 mm Hg. PAD decreased at 24 hours among all comers, but 47% of patients received LVMU devices to support this reduction.