Impact of intra-aortic balloon pump support on cerebral blood flow velocity during venoarterial ECMO

Venoarterial extracorporeal membrane oxygenation (V-A ECMO) is frequently combined with intra-aortic balloon pump (IABP) support in patients with refractory cardiogenic shock. Although IABP may reduce V-A ECMO-related afterload, its effect on cerebral perfusion remains uncertain. We aimed to assess the impact of IABP support on middle cerebral artery (MCA) blood flow velocity measured by transcranial Doppler ultrasonography in patients receiving V-A ECMO.

We conducted a retrospective study in our tertiary intensive care unit between November 2021 and May 2022. Adults receiving femoro-femoral V-A ECMO with concomitant IABP support were screened. Patients with documented transcranial Doppler monitoring parameters were included. MCA blood flow velocities and systemic hemodynamic variables were compared between IABP standby mode and active IABP support at a 1:1 assist ratio.

Among 88 screened patients, 21 were included. IABP support was associated with lower peak systolic and pre-ejection arterial pressures, whereas mean arterial pressure remained unchanged. MCA systolic and late diastolic flow velocities decreased during IABP support, while early diastolic velocity increased. Overall, MCA mean flow velocity was significantly lower during IABP support than during standby mode (42 [39-55] vs. 59 [48-64] cm·s^-1, p < 0.001). Higher unassisted pulse pressure and greater reduction in late diastolic flow velocity were associated with a larger decrease in MCA mean flow velocity during IABP support.

In patients receiving V-A ECMO, IABP support was associated with reduced MCA mean flow velocity despite unchanged mean arterial pressure, a TCD pattern consistent with a net decrease in cerebral blood flow, potentially related to IABP-induced changes in arterial waveform and cerebral hemodynamics.