Cerebral Complications

Arterial hypertension is a major risk factor for cerebrovascular diseases, increasing the likelihood of ischemic and hemorrhagic events in the brain. The vascular damage induced by high blood pressure alters cerebral perfusion, leading to progressive endothelial dysfunction, arterial stiffness, and impaired autoregulation of blood flow.

Alterations in Cerebral Blood Flow Regulation

Hypertension profoundly affects the ability of cerebral vessels to autoregulate blood flow, making the brain more vulnerable to pressure fluctuations.

• Impaired autoregulation: In normotensive individuals, cerebral blood flow remains relatively constant due to the ability of vessels to dilate or constrict in response to pressure variations. In chronic hypertension, this ability is progressively lost, increasing the risk of hypoperfusion or hyperperfusion during blood pressure fluctuations.
• Risk of hypoperfusion: Sudden drops in blood pressure may lead to cerebral hypoperfusion, resulting in transient neurological deficits and syncope.
• Risk of hypertensive encephalopathy: In hypertensive crises, the loss of vascular autoregulation can lead to diffuse cerebral edema, causing severe headache, confusion, altered consciousness, and, in severe cases, coma.

These alterations make the hypertensive brain more susceptible to both acute and chronic vascular damage, highlighting the importance of effective blood pressure control in preventing neurological complications.

Major Cerebrovascular Events

Cerebrovascular events are among the most severe complications of hypertension. The most common cerebrovascular event associated with hypertension is stroke, which can be ischemic or hemorrhagic:

• Ischemic stroke: In most cases, it is associated with the progression of cerebral atherosclerosis and the formation of thrombi that occlude cerebral vessels. Hypertension contributes to plaque formation and instability, increasing the risk of arterial thrombosis or embolism.
• Hemorrhagic stroke: Elevated blood pressure exerts increased wall stress on cerebral arterioles, promoting the formation and rupture of Charcot-Bouchard microaneurysms, particularly in the basal ganglia, thalamus, pons, and cerebellum.

Major vascular events can result in permanent disabling sequelae, such as motor deficits, aphasia, and cognitive impairment, significantly impacting the patient's quality of life.

Leukoaraiosis and Vascular Dementia

Beyond strokes, hypertension is responsible for more insidious and progressive cerebral alterations that may go unnoticed until advanced stages.

• Leukoaraiosis: A chronic diffuse injury of the subcortical white matter, visible on MRI as hyperintense areas, resulting from repeated silent ischemic micro-events. It is strongly associated with hypertension and small vessel disease.
• Vascular dementia: The progressive accumulation of cerebral ischemic damage impairs cognitive functions, leading to cognitive decline, memory disturbances, and executive dysfunction. Hypertension is one of the primary causes of vascular dementia.

The impairment of cerebral microcirculation and the cumulative effect of small lacunar infarcts contribute to the progressive reduction of cognitive and functional abilities in hypertensive patients.

Conclusion

The cerebral complications of arterial hypertension include both acute ischemic events, such as stroke, and chronic progressive damage, such as leukoaraiosis and vascular dementia. Maintaining adequate blood pressure control and managing cardiovascular risk factors are crucial strategies for preventing brain damage and its long-term consequences.

References
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