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Why do treated hypertensives suffer strokes? An internist's perspective
1Medical Service, VA Medical Center and University of Minnesota Medical School, Minneapolis, MN 55417, USA. simo016@tc.umn.edu
Insights
Hypertension treatment effectively prevents lacunar strokes but is less effective for atherothrombotic and cardioembolic strokes. Future research should focus on these subtypes, considering factors beyond blood pressure for stroke prevention.
Area of Science:
- Neurology
- Cardiovascular Medicine
- Public Health
Background:
- Stroke remains a leading cause of death despite widespread hypertension management.
- Antihypertensive therapy shows greater efficacy in preventing hemorrhagic strokes than ischemic strokes.
Purpose of the Study:
- To investigate why antihypertensive therapy is only partially effective in preventing ischemic strokes.
- To explore differences in pathogenesis and treatment across ischemic stroke subtypes.
Main Methods:
- Analysis of stroke subtypes: small-vessel arteriopathic (lacunar), large-artery atherothrombotic, and cardioembolic.
- Review of the role of hypertension in the pathogenesis of each subtype.
- Consideration of overtreatment effects (J-curve phenomenon) in specific populations.
Main Results:
- Hypertension is a primary cause of lacunar strokes, largely preventable with antihypertensive therapy.
- Hypertension plays a lesser role in atherothrombotic strokes, which are less impacted by current antihypertensive treatments.
- Overtreatment of hypertension, particularly in the elderly, may paradoxically increase stroke risk.
Conclusions:
- Judicious antihypertensive therapy is crucial for preventing lacunar strokes.
- Future therapeutic strategies must target atherothrombotic and cardioembolic stroke prevention.
- Promising avenues include surgical refinement, plaque stabilization pharmacotherapy, and advanced diagnostics like transesophageal echocardiography.
Abstract:
Despite widespread treatment of hypertension, stroke continues to be the third leading cause of death in the United States. Antihypertensive therapy is more effective in preventing hemorrhagic strokes than ischemic strokes. In order to understand the reasons why antihypertensive therapy is only partially successful in the eradication of ischemic strokes, differences in the pathogenesis and treatment of subtypes of stroke must be considered. There are three main stroke subtypes of ischemic strokes: small-vessel arteriopathic (lacunar), large-artery atherothrombotic, and cardioembolic. Hypertension is the major cause of lacunar strokes but plays a lesser role in the pathogenesis of atherothrombotic strokes. Antihypertensive therapy prevents the majority of lacunar strokes but may not have a major impact on the occurrence of atherothrombotic strokes. Due to impaired cerebral autoregulation, overtreatment of hypertension, especially in the elderly and in patients with previous strokes, may paradoxically lead to stroke (J-curve). Assuming that the majority of lacunar strokes are prevented by judicious antihypertensive therapy, future therapeutic efforts should concentrate on the prevention of atherothrombotic and cardioembolic strokes. In this regard, refinement of surgical techniques, pharmacologic approaches aimed at plaque stabilization, and the application of transesophageal echocardiography for the diagnosis of embolic strokes (and anticoagulation for a probable source) are promising. Besides the obvious reasons of noncompliance and inadequate therapy, overly aggressive treatment of hypertension in the elderly and stroke mechanisms unrelated to blood pressure may explain the occurrence of strokes despite our efforts to treat hypertension.