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Hypertension mechanisms causing stroke
1Department of Neurology, Lund University Hospital, Sweden. Barbro.Johansson@neurol.lu.se
Insights
Hypertension significantly contributes to stroke through various mechanisms affecting cerebral arteries and the blood-brain barrier. Understanding these complex pathways is crucial for stroke prevention and managing hypertension.
Area of Science:
- Neurology
- Cardiovascular Medicine
- Pathophysiology
Background:
- Hypertension is a primary risk factor for stroke.
- The intricate mechanisms linking hypertension to cerebrovascular disease are not widely understood.
Purpose of the Study:
- To elucidate the multifaceted mechanisms by which hypertension causes stroke.
- To highlight the role of hypertension in the development of cerebrovascular complications and vascular dementia.
Main Methods:
- Review of established knowledge on hypertension's effects on cerebral vasculature.
- Analysis of pathological changes in intracerebral arteries due to elevated blood pressure.
- Examination of endothelial dysfunction, thrombus formation, and degenerative changes.
Main Results:
- High intraluminal pressure alters endothelium and smooth muscle function, increasing blood-brain barrier permeability and causing edema.
- Endothelial damage and altered blood cell interactions promote thrombi and ischemic lesions; fibrinoid necrosis leads to lacunar infarcts.
- Hypertension accelerates arteriosclerosis, increasing risks from stenosis and embolism, and contributes to intracerebral hemorrhages. It also increases vascular dementia risk.
Conclusions:
- Hypertension initiates stroke through diverse mechanisms impacting cerebral arteries, including endothelial dysfunction, microvascular changes, and accelerated atherosclerosis.
- These mechanisms contribute to ischemic stroke, lacunar infarcts, intracerebral hemorrhage, and vascular dementia.
- Recognizing the complexity of hypertension-related cerebrovascular disease is vital for effective prevention and treatment strategies.
Abstract:
1. Although it is well established that hypertension is the main risk factor for stroke, the complexity of cerebrovascular problems related to hypertension is not generally appreciated. 2. Hypertension can cause stroke through many mechanisms. A high intraluminal pressure will lead to extensive alteration in endothelium and smooth muscle function in intracerebral arteries. The increased stress on the endothelium can increase permeability over the blood-brain barrier and local or multifocal brain oedema. Endothelial damage and altered blood cell-endothelium interaction can lead to local thrombi formation and ischaemic lesions. Fibrinoid necrosis can cause lacunar infarcts through focal stenosis and occlusions. Degenerative changes in smooth muscle cells and endothelium predisposes for intracerebral haemorrhages. Furthermore, hypertension accelerates the arteriosclerotic process, thus increasing the likelihood for cerebral lesions related to stenosis and embolism originating from large extracranial vessels, the aortic arch and from the heart. 3. Adaptive structural changes in the resistance vessels, while having the positive effect of reducing the vessel wall tension, have the negative consequence of increased peripheral vascular resistance that may compromise the collateral circulation and enhance the risk for ischaemic events in connection with episodes of hypotension or distal to a stenosis. 4. Hypertension is clearly a risk factor for vascular dementia. All the mechanisms referred to above may be important.