Cerebral Blood Flow during Exercise in Heart Failure: Impact of Ventricular Assist Devices

Introduction In healthy individuals cerebral blood flow (CBF) increases during exercise, but few studies have compared changes in CBF during exercise in patients with heart failure (HF) to healthy controls (CTRL), or assessed the effects of left ventricular assist devices (LVADs). We hypothesised that subjects implanted with LVADs would exhibit impaired cerebrovascular responses to cycle exercise when compared to age- and sex-matched healthy CTRL subjects, but enhanced responses relative to subjects with HF. Methods Internal carotid artery [ICA] blood flow, and intra-cranial middle [MCAv] and posterior cerebral [PCAv] artery velocities were measured continuously using Doppler ultrasound, alongside cardiorespiratory measures at rest and in response to an incremental submaximal cycle ergometer exercise protocol in 9 LVAD participants (58±15yrs; 87±16kg; 172±8 cm, 6♂), 9 age- and sex-matched subjects with HF (58±8yrs; 84±11kg;177±6cm), and 9 CTRL (55±14yrs; 74±16kg;168±10cm). Results At rest, ICA hemodynamics (velocity, shear rate and flow) were greater in CTRLs and LVADs than HF (p

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