Cerebral Haemodynamics: Effects of Systemic Arterial Pulsatile Function and Hypertension.

PURPOSE OF REVIEW: Concepts of pulsatile arterial haemodynamics, including relationships between oscillatory blood pressure and flow in systemic arteries, arterial stiffness and wave propagation phenomena have provided basic understanding of underlying haemodynamic mechanisms associated with elevated arterial blood pressure as a major factor of cardiovascular risk, particularly the deleterious effects of isolated systolic hypertension in the elderly. This topical review assesses the effects of pulsatility of blood pressure and flow in the systemic arteries on the brain. The review builds on the emerging notion of the "pulsating brain", taking into account the high throughput of blood flow in the cerebral circulation in the presence of mechanisms involved in ensuring efficient and regulated cerebral perfusion. RECENT FINDINGS: Recent studies have provided evidence of the relevance of pulsatility and hypertension in the following areas: (i) pressure and flow pulsatility and regulation of cerebral blood flow, (ii) cerebral and systemic haemodynamics, hypertension and brain pathologies (cognitive impairment, dementia, Alzheimer's disease), (iii) stroke and cerebral small vessel disease, (iv) cerebral haemodynamics and noninvasive estimation of cerebral vascular impedance, (v) cerebral and systemic pulsatile haemodynamics and intracranial pressure, (iv) response of brain endothelial cells to cyclic mechanical stretch and increase in amyloid burden. Studies to date, producing increasing epidemiological, clinical and experimental evidence, suggest a potentially significant role of systemic haemodynamic pulsatility on structure and function of the brain.