Hypertension and the Brain: A Risk Factor for More Than Heart Disease.

BACKGROUND: Cerebral small vessel disease (cSVD), a common risk factor for cognitive impairment, involves unspecific arteriopathy characterized by hypertrophy and endothelial dysfunction that alter cerebrovascular function and auto-regulation of cerebral blood flow (CBF). Microbleedings, subcortical lacunar infarctions and diffuse areas of white matter lesions resulting from vascular injury are associated with reduced cognitive function mostly characterized by difficulties in learning and retention, attention deficits, gait disorders or depression. In recent years, it has become evident that vascular risk factors contribute to the development of cSVD and associated vascular cognitive impairment (VCI). Among them, hypertension emerged as such a major modifiable risk factor since the brain presents an early target for organ damage due to changes in blood pressure (BP). Subsequently both high and, especially in the elderly, low BP have been linked to cognitive decline, which initiated controversial discussions about BP control as a potential therapeutic strategy to achieve optimal brain perfusion and thus, reduce the occurrence of cSVD and cognitive dysfunction. Yet, recent randomized controlled trials examined the impact of anti-hypertensive therapy on cognitive performance with conflicting results.
SUMMARY: In light of the current knowledge, it becomes apparent that there is an urgent need to understand the mechanisms underlying hypertension-induced cerebrovascular complications in order to identify effective therapeutic targets to prevent and most importantly also reverse cognitive decline mediated through hypertension. KEY MESSAGE: This review summarizes the current knowledge of cSVD pathogenesis as well as possible links to hypertension-mediated cerebrovascular complications. By pointing out knowledge gaps, it aims to spur future studies in search of specific targets helping to prevent therapy failures and decelerate the rapidly progressing neuro-degeneration of patients suffering from cerebrovascular diseases emanating from hypertension.