Abstract
Purpose In advanced heart failure (HF) patients, a normal cardiac output is restored after continuous-flow left ventricular assist device (CF-LVAD) implantation. Previous studies have suggested that cerebral autoregulation is preserved. However, it is not known whether CF-LVAD therapy affects the cerebrovascular reactivity to a metabolic challenge. Hypothesis CF-LVAD patients will have a similar cerebrovascular response to a CO2-retention challenge compared with HF patients and healthy controls. Methods Angle-corrected Doppler ultrasound images of the middle cerebral artery (MCA) were recorded immediately before and at the end of a 30s breathhold in 10 healthy controls, 4 HF and 7 CF-LVAD (HM II) patients. Time-averaged maximum blood velocity (TAMAX), peak flow velocity (Vmax), Pulsatility Index (PI) and Resistance Index (RI) were determined by tracing of the blood velocity envelope. Statistical differences were determined with 2-way ANOVA (% change is illustrated graphically). Results In the MCA, significant baseline differences in TAMAX, Vmax, PI and RI existed between groups (all P Conclusion A metabolic challenge has a differential impact on cerebrovascular hemodynamics of HF and CF-LVAD patients compared with healthy controls. The pilot data suggest that cerebrovascular reserve may be altered already in HF and not further modulated after CF-LVAD implantation.
Published Version
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