Abstract 15140: Cerebral Hemodynamics During Left Ventricular Assist Device Speed Titration

Introduction: Left ventricular assist device (LVAD) speed may be titrated to optimize cardiopulmonary hemodynamics, but the impact on cerebral blood flow remains poorly understood.

Hypothesis: Here, we monitored cerebral hemodynamics during ramp studies, to test the hypothesis that LVAD speed correlates with cerebral blood flow and cerebral autoregulation.

Methods: Patients with HeartMate3 LVADs underwent ramp study for optimization, during which cerebral blood flow velocity (CBFv) was continuously monitored by transcranial Doppler (TCD), and blood pressure was continuously monitored by finger plethysmography. Mx index was used a measure of autoregulation which correlates blood pressure and CBFv (i.e. high Mx index indicates poor autoregulation). The treating cardiologist determined the optimal speed based on cardiopulmonary dynamics (other speeds were categorized as sub-optimal).

Results: Of 23 patients, 5 did not undergo speed changes. At least two speeds were explored in the remaining 18 patients. When comparing the lowest and highest speeds for each patient, higher speeds resulted in higher CBFv (p=0.02; Figure 1a ), but no change in autoregulation (p=0.38; Figure 1b ). However, when comparing the optimal and suboptimal LVAD speeds, CVFv was similar (p=0.89; Figure 2a ,), whereas the optimal speed was associated with a trend toward favorable autoregulation (p=0.09; Figure 2b ).

Conclusions: Cerebral blood flow velocity is sensitive to LVAD speed titration, and cardiopulmonary optimization may improve cerebral autoregulation. A larger cohort and a broader range of speeds may further clarify the impact of speed titration on cerebral hemodynamics.