Stroke prevention: hypertension, diabetes, tobacco, and lipids

Stroke vs. Preeclampsia: Dangerous Liaisons of Hypertension and Pregnancy

Stroke during pregnancy and preeclampsia are two distinct but interrelated medical conditions, sharing a common denominator-blood control failure. Along with cardiovascular diseases, diabetes, dyslipidemia, and hypercoagulability, hypertension is undoubtedly a major risk factor associated with stroke. Even though men have higher age-specific stroke rates, women are facing higher life-long stroke risk, primarily due to longer life expectancy. Sex hormones, especially estrogen and testosterone, seem to play a key link in the chain of blood pressure control differences between the genders. Women affected with stroke are more susceptible to experience some atypical stroke manifestations, which might eventually lead to delayed diagnosis establishment, and result in higher morbidity and mortality rates in the population of women. Preeclampsia is a part of hypertensive disorder of pregnancy spectrum, and it is common knowledge that women with a positive history of preeclampsia are at increased stroke risk during their lifetime. Preeclampsia and stroke display similar pathophysiological patterns, including hypertension, endothelial dysfunction, dyslipidemia, hypercoagulability, and cerebral vasomotor reactivity abnormalities. High-risk pregnancies carrying the burden of hypertensive disorder of pregnancy have up to a six-fold higher chance of suffering from stroke. Resemblance shared between placental and cerebral vascular changes, adaptations, and sophisticated auto-regulatory mechanisms are not merely coincidental, but they reflect distinctive and complex cardiovascular performances occurring in the maternal circulatory system during pregnancy. Placental and cerebral malperfusion appears to be in the midline of both of these conditions; placental malperfusion eventually leads to preeclampsia, and cerebral to stoke. Suboptimal performances of the cardiovascular system are proposed as a primary cause of uteroplacental malperfusion. Placental dysfunction is therefore designated as a secondary condition, initiated by the primary disturbances of the cardiovascular system, rather than an immunological disorder associated with abnormal trophoblast invasion. In most cases, with properly and timely applied measures of prevention, stroke is predictable, and preeclampsia is a controllable condition. Understanding the differences between preeclampsia and stroke in pregnancy is vital for healthcare providers to enhance their clinical decision-making strategies, improve patient care, and promote positive maternal and pregnancy outcomes. Management approaches for preeclampsia and stroke require a multidisciplinary approach involving obstetricians, neurologists, and other healthcare professionals.

Preclinical and Clinical Evidence for the Involvement of Sphingosine 1-Phosphate Signaling in the Pathophysiology of Vascular Cognitive Impairment

Sphingosine 1-phosphates (S1Ps) are bioactive lipids that mediate a diverse range of effects through the activation of cognate receptors, S1P₁-S1P₅. Scrutiny of S1P-regulated pathways over the past three decades has identified important and occasionally counteracting functions in the brain and cerebrovascular system. For example, while S1P₁ and S1P₃ mediate proinflammatory effects on glial cells and directly promote endothelial cell barrier integrity, S1P₂ is anti-inflammatory but disrupts barrier integrity. Cumulatively, there is significant preclinical evidence implicating critical roles for this pathway in regulating processes that drive cerebrovascular disease and vascular dementia, both being part of the continuum of vascular cognitive impairment (VCI). This is supported by clinical studies that have identified correlations between alterations of S1P and cognitive deficits. We review studies which proposed and evaluated potential mechanisms by which such alterations contribute to pathological S1P signaling that leads to VCI-associated chronic neuroinflammation and neurodegeneration. Notably, S1P receptors have divergent but overlapping expression patterns and demonstrate complex interactions. Therefore, the net effect produced by S1P represents the cumulative contributions of S1P receptors acting additively, synergistically, or antagonistically on the neural, vascular, and immune cells of the brain. Ultimately, an optimized therapeutic strategy that targets S1P signaling will have to consider these complex interactions.

Promising Anti-stroke Signature of Voglibose: Investigation through In- Silico Molecular Docking and Virtual Screening in In-Vivo Animal Studies

Background:

Postprandial hyperglycemia considered to be a major risk factor for cerebrovascular complications.

Objective:

The current study was designed to elucidate the beneficial role of voglibose via in-silico in vitro to in-vivo studies in improving the postprandial glycaemic state by protection against strokeprone type 2 diabetes.

Material and Methods:

In-Silico molecular docking and virtual screening were carried out with the help of iGEMDOCK+ Pymol+docking software and Protein Drug Bank database (PDB). Based on the results of docking studies, in-vivo investigation was carried out for possible neuroprotective action. T2DM was induced by a single injection of streptozotocin (90mg/kg, i.v.) to neonates. Six weeks after induction, voglibose was administered at the dose of 10mg/kg p.o. for two weeks. After eight weeks, diabetic rats were subjected to middle cerebral artery occlusion, and after 72 hours of surgery, neurological deficits were determined. The blood was collected for the determination of serum glucose, CK-MB, LDH and lipid levels. Brains were excised for determination of brain infarct volume, brain hemisphere weight difference, Na+-K+ ATPase activity, ROS parameters, NO levels, and aldose reductase activity.

Results:

In-silico docking studies showed good docking binding score for stroke associated proteins, which possibly hypotheses neuroprotective action of voglibose in stroke. In the present in-vivo study, pre-treatment with voglibose showed a significant decrease (p<0.05) in serum glucose and lipid levels. Voglibose has shown significant (p<0.05) reduction in neurological score, brain infarct volume, the difference in brain hemisphere weight. On biochemical evaluation, treatment with voglibose produced significant (p<0.05) decrease in CK-MB, LDH, and NO levels in blood and reduction in Na+-K+ ATPase, oxidative stress, and aldose reductase activity in brain homogenate.

Conclusion:

In-silico molecular docking and virtual screening studies and in-vivo studies in MCAo induced stroke, animal model outcomes support the strong anti-stroke signature for possible neuroprotective therapeutics.

Adherence to Hypertension Medications and Lifestyle Recommendations among Underserved African American Middle-Aged and Older Adults

Background: For African American middle-aged and older adults with hypertension, poor adherence to medication and lifestyle recommendations is a source of disparity in hypertension outcomes including higher rates of stroke in this population relative to whites. Aims: To study demographic, social, behavioral, cognitive, and medical predictors of adherence to medication and lifestyle recommendations among underserved African American middle-aged and older adults with hypertension. Methods: This was a community-based cross-sectional survey in South Los Angeles with 338 African American middle-aged and older adults with hypertension who were 55 years or older. Age, gender, continuity of care, comorbidity, financial difficulty, self-rated health, depression, educational attainment, adherence knowledge, and adherence worries were the independent variables. Data was analyzed using linear regression with two outcomes, namely, adherence to medication (measured by the first 9 items of the Blood Pressure Self-Care Scale) and adherence to lifestyle recommendations (measured by the second 9 items of the Blood Pressure Self-Care Scale). Results: There were about twice more females than males, with a total mean age of 70 years (range 55–90 years). Various demographic, social, behavioral, and medical factors predicted adherence to medication but not adherence to lifestyle recommendations. Females with hypertension with higher continuity of care, less financial strain, higher knowledge, less negative general beliefs, and concerns about antihypertensive medications had higher adherence to antihypertensive medications. The presence of depressive symptoms, reduced knowledge, and disease management worries were associated with a reduced adherence to lifestyle recommendations. Conclusions: There seem to be fewer demographic, social, behavioral, cognitive, and medical factors that explain adherence to lifestyle recommendations than adherence to medication in economically disadvantaged underserved African American middle-aged and older adults with hypertension. More research is needed on factors that impact adherence to lifestyle recommendations of African American middle-aged and older adults with hypertension.

Fingolimod Inhibits Inflammation but Exacerbates Brain Edema in the Acute Phases of Cerebral Ischemia in Diabetic Mice

Background and Purpose: Diabetes mellitus increases stroke incidence and mortality and hampers functional recovery after stroke. Fingolimod has been shown to improve neurofunctional recovery and reduce brain infarction after ischemic injury in mice without comorbidities. In this work, we investigated the effects of fingolimod in diabetic mice after transient middle cerebral artery occlusion (tMCAO).

Methods: Hyperglycemia was induced by a single bolus streptozotocin injection. Adult male ICR mice (n = 86) underwent 1-h tMCAO surgery and received intraperitoneal injection of fingolimod (1 mg/kg) or vehicle immediately after reperfusion. Clark neurological score, brain infarction and edema, blood–brain barrier (BBB) integrity, apoptosis, and inflammation were evaluated at 24 h after tMCAO.

Results: Fingolimod treatment reduced the number of infiltrated inflammatory cells and lowered the mRNA level of Tnfα. It also increased the ratio of Bcl-2/Bax. However, fingolimod significantly aggravated brain edema and reduced the expression levels of tight junction proteins ZO-1 and Occludin. The negative impacts of fingolimod on BBB integrity outweighed its beneficial effects in anti-inflammation, which resulted in the lack of improvement in endpoint outcomes at 24 h after tMCAO.

Conclusion: Caution should be taken in considering the acute treatment using fingolimod for ischemic stroke with diabetes comorbidity.

Clinical Outcome of Edoxaban vs. Vitamin K Antagonists in Patients with Atrial Fibrillation and Diabetes Mellitus: Results from a Multicenter, Propensity-Matched, Real-World Cohort Study

Diabetes mellitus (DM) is a chronic metabolic disease which is independently associated with unfavorable clinical outcomes in patients with atrial fibrillation (AF). Few real-world data are available about the clinical performance of non-vitamin K oral anticoagulants (NOACs) among patients with atrial fibrillation and diabetes. The aim of our propensity score-matched cohort study was to compare the safety and effectiveness of Edoxaban versus well-controlled vitamin K antagonists (VKAs) therapy among this population. In this study, we considered patients with AF and diabetes on Edoxaban or VKAs therapy included in the multicenter Atrial Fibrillation Research Database (NCT03760874). The occurrence of major bleedings (MB) and thromboembolic events (a composite of ischemic stroke, transient ischemic attack, systemic embolism) was respectively considered primary safety and effectiveness outcome. We identified 557 AF patients with diabetes who received Edoxaban (n: 230) or VKAs (n: 327) treatment. After propensity score matching analysis, 135 Edoxaban and 135 VKA recipients with similar clinical characteristics were evaluated. The mean follow-up was 27 ± 3 months. The incidence rate of thromboembolic events (TE) was 3.0 per 100 person-years (1.11 in Edoxaban vs. 1.9 in the VKA group, hazard ratio (HR): 0.59; 95% confidence interval (CI), 0.14 to 2.52; p = 0.48). The incidence rate of major bleedings (MB) was 3.7 per 100 person-years (1.2 in Edoxaban vs. 2.7 in the VKA group, HR: 0.43; 95% CI: 0.10 to 1.40; p = 0.14). The incidence rate of intracranial hemorrhage was 0.35 per 100 person-years in Edoxaban vs. 0.74 in the VKA group (HR: 0.49; 95% CI: 0.05 to 5.54; p = 0.56). A positive net clinical benefit (NCB) of Edoxaban over VKAs was found (+1.39). Insulin therapy (HR: 1.76, p = 0.004) and glycated hemoglobin (HR: 1.17, p = 0.002) were found to be independent predictors of TE; moreover, the concomitant use of antiplatelet drugs (HR: 2.41, p = 0.001) was an independent predictor of MB. Conclusions: Our data support the hypothesis of the safety and efficacy of Edoxaban for use in patients with AF and diabetes, justified by a favorable NCB over VKAs.

Association between carotid plaque and Parkinson's disease

Background

Epidemiological studies show that patients with Parkinson's disease (PD) are prone to have a reduced incidence of ischemic cerebrovascular disease. Previous studies show the correlation between PD and the lipids serum levels. The PD,s patients are found with a reduced serum level of triglyceride and low-density lipoprotein cholesterol (LDL-C); thus, the level of serum uric acid (UA) is closely related to the occurrence and development of PD. Patients with low serum UA levels have a higher chance of developing PD than the ones who do not. However, the relationship between carotid plaques and PD is still unknown.

Methods

Our study was based on 68 patients with PD (known as the PD group) and 81 people without PD (known as the control group). Patients in the PD group were of the same age and gender. Both groups were recorded and analyzed for UA, LDL-C, and carotid plaques or intima-media thickness (IMT). The PD group was then divided into three subgroups: the stable plaque group, the unstable plaque group, and the non-plaque group.

Results

In the present study, the PD group showed a significantly lower level of UA and LDL-C than the control group (P<0.01); somehow there were no statistically significant differences in the IMT and plaque incidence between the two groups (P>0.05). There were also no significant differences (P>0.05) in both the LDL-C and UA levels in all subgroups, but there was a close relation in both age and duration of disease to IMT. According to the Hoehn and Yahr staging scale, serum levels of LDL-C were inversely correlated in PD patients, while UA was related to the duration of the disease.

Conclusions

Our study suggested that there were no differences in carotid artery arteriosclerosis plaque and IMT, but the PD progress was indeed correlated with IMT. Meanwhile, LDL-C and UA had different priorities in H&Y and disease progression.

Atrial fibrillation in patients with diabetes: molecular mechanisms and therapeutic perspectives

Atrial fibrillation (AF) remains the most frequent sustained cardiac arrhythmia worldwide and its incidence increases with ageing, cardiovascular risk factors and comorbidities. Prevalence of diabetes mellitus (DM) is growing fast and is assuming pandemic proportions mostly due to overnutrition and sedentary habits. Experimental and clinical evidences suggest that DM and AF are strongly interconnected. The present review addresses in detail new molecular pathways implicated in the etiology of AF and their relevance for mechanism-based therapeutic strategies in this setting. Advances in risk stratification, drug therapy (i.e., novel anticoagulants) and catheter ablation are also described.

Reduced serum levels of triglyceride, very low density lipoprotein cholesterol and apolipoprotein B in Parkinson's disease patients

BACKGROUND

Previous studies have shown a lower incidence of stroke in Parkinson's disease (PD) patients. The role of the lipids and lipoproteins as risk factors for stroke is uncertain in the lower prevalence of stroke in PD patients.

OBJECTIVES

To explore the lipids and lipoproteins serum levels in PD patients.

METHODS

A retrospective study was performed on 110 PD patients (PD group), 130 controls with non-cerebrovascular neurological diseases (OD group), 140 acute intracerebral hemorrhage patients (ICH group) and 140 acute cerebral infarction patients (CI group). The records about serum levels of lipids and lipoproteins were analyzed.

RESULTS

There were significant differences for the serum level of triglyceride (F = 5.031, p=0.002), very low density lipoprotein cholesterol (F = 5.313, p=0.001), apolipoprotein B (F = 16.038, p<0.0001) in the four groups. PD group had a significantly lower serum level of triglyceride (TG) than the OD (p=0.032), ICH (p=0.00047) and CI (p=0.001) groups. Very low density lipoprotein cholesterol (VLDL-C) serum level was significantly lower in PD group than in OD (p=0.039), ICH (p=0.00021) and CI (p=0.001) groups. There was a significantly lower serum level of apolipoprotein B (apo B) in PD group than in OD (p=0.002), ICH (p<0.0001) and CI (p<0.0001) groups.

CONCLUSIONS

There are reduced serum levels of TG, VLDL-C and apo B in PD patients, which may be related to the decreased prevalence of stroke in PD patients.

Type 2 diabetes and cognitive impairment: linking mechanisms

This manuscript provides a brief review of current concepts in the mechanisms potentially linking type-2-diabetes (T2D) with cognitive impairment. Existing epidemiologic studies, imaging studies, autopsy studies, and clinical trials provide insights into the mechanisms linking T2D and cognitive impairment. There seems to be little dispute that T2D can cause cerebrovascular disease and thus cause vascular cognitive impairment (VCI). Whether T2D can cause late onset Alzheimer's disease (LOAD) remains to be elucidated. Many epidemiologic studies show an association between T2D and cognitive impairment, but the association with VCI seems to be stronger compared to LOAD, suggesting that cerebrovascular disease may be the main mechanism linking T2D and cognitive impairment. Imaging studies show an association between T2D and imaging markers of LOAD, but these observations could still be explained by cerebrovascular mechanisms. Autopsy studies are few and conflicting, with some suggesting a predominantly cerebrovascular mechanism, and others providing support for a neurodegenerative mechanism. Thus far, the evidence from clinical trials is mixed in supporting a causal association between T2D and cognitive impairment, and most clinical trials that can answer this question are yet to be reported or finished. Given the epidemic of T2D in the world, it is important to elucidate whether the association between T2D and cognitive impairment, particularly LOAD, is causal, and if so, what the mechanisms are.

Belgian global implementation of cardiovascular and stroke risk assessment study: methods and baseline data of the BELGICA-STROKE STUDY

OBJECTIVES

BELGICA-STROKE is a longitudinal study to enhance the use of online cardiovascular risk prediction scores based on the SCORE 10-year risk estimates for fatal cardiovascular disease (adapted for Belgium) and the Framingham 10-year stroke risk and to evaluate their impact on the cardiovascular risk profile of hypertensive patients. Methods and baseline characteristics are described here.

DESIGN

Prospective, multicenter study in primary care.

METHODS

General practitioners (N = 810) recruited consecutive hypertensive patients aged >40 years who were not at blood pressure goal and assessed them every 4 months. The estimated 10-year risks for fatal cardiovascular disease and stroke were available on a secured, specially designed study website. The calculated risk profile of a patient was modifiable by adding treatment goals in order to increase awareness and motivation of both physician and patient. An automated feedback on goal-level attainment and both cardiovascular risk scores was provided.

RESULTS

Mean age of the 15,744 patients was 66.3 years: 51.9% were men, 77.8% had excess weight, 19.4% were smokers, and 25.9% had diabetes. Left ventricle hypertrophy was present in 20.0%, atrial fibrillation in 5.8%. Mean blood pressure was 153.8/88.2 mmHg, mean cholesterol 211.5 mg/dl. Most patients (89.2%) received antihypertensive medication, of which 36.9% was monotherapy. Mean estimated 10-year stroke risk was 19.1%, and mean estimated 10-year fatal cardiovascular disease risk 5.9%.

CONCLUSIONS

The 10-year estimated stroke and fatal cardiovascular disease risks were moderate to high in hypertensive patients not at goal blood pressure, emphasizing the importance of global cardiovascular risk factor assessment.

[Study of the stroke and coronary risks in hypertensive patients over 54 years of age in the primary care practice]

BACKGROUND AND OBJECTIVES

Quantification of stroke risk is not always performed in hypertensive patients in Primary Care.

METHODS

This was an epidemiological study in hypertensive patients aged 55 years and older attending primary care centres in Spain. The D'Agostino Stroke Risk Scale, using data from the Framingham Study, was used for assessment of stroke risk.

RESULTS

We analysed 4,945 patients (mean age, 66.8 years; 50.9% females). Mean blood pressure (BP) values were 145/86 mmHg in men and 143.7/84.7 mmHg in women (p < 0.001). The majority of patients (80.5%) showed high BP values that were above the values recommended in the guidelines, despite most of them (89.6%) receiving pharmacological antihypertensive treatment. 41% of patients were diabetics. The 10-year global risk of stroke was 22.5%, and was higher in men (28.6% vs. 16.8%; P < 0.001). The risk of stroke increased with age, being more marked in women. Several risk factors showed a statistically significant association with the risk of stroke. From higher to lower significance, these risk factors were: age, left ventricular hypertrophy (LVH), cardiovascular disease, systolic BP, auricular fibrillation, diabetes, cigarette smoking, control of BP, gender, and antihypertensive treatment. The 10-year coronary risk was higher in men (24.2% vs. 16.0%; p < 0.001) and was significantly related to the 10-year risk of stroke (r = 0.626).

CONCLUSIONS

The risk of stroke in the Spanish hypertensive population is high, and is significantly higher in men, although it shows a larger age-related increase in women. Linear regression analysis showed a moderate, but statistically significant, correlation between coronary risk and risk of stroke. Apart from all the variables included in the Framingham Stroke Risk Model, gender, control of BP, and antihypertensive treatment accounted significantly and independently as calculated risk factors for incidence of stroke.

Rostral cerebellar arterial infarct in two cats

A 10-year-old female neutered domestic shorthair (DSH) cat and a 6-year-old female neutered Siamese cat were presented following a peracute onset of decerebellate rigidity and a cerebellar vestibular syndrome, respectively. In both cats, physical examination and routine blood tests were unremarkable, as was routine analysis of cerebrospinal fluid obtained from the DSH cat. Based on the magnetic resonance imaging (MRI) features - focal wedge-shaped lesion in the cerebellum characterised by hyperintensity in T2-weighted, T2( *)-gradient echo and fluid attenuated inversion recovery (FLAIR) images - a presumptive diagnosis of cerebellar infarct was made in both cases. In the DSH cat, the post-mortem examination confirmed the diagnosis of cerebellar infarct and additionally found acute renal infarcts and a pulmonary neoplasia. In the Siamese cat, ultrasonographic evaluation of the heart revealed a probable low-grade chronic valvular endocarditis which was thought to be a potential source of thromboembolism. This paper describes the first two cases - one confirmed and the other suspected - of cerebellar infarct in the cat. The in vivo potential diagnostic value of the MRI study is highlighted. Cerebellar infarcts should be included in the differential diagnosis of cat with a peracute onset of cerebellar signs regardless of the severity of neurological deficits.

Blood pressure control and risk of stroke in untreated and treated hypertensive patients screened from clinical practice: results of the ForLife study

OBJECTIVES

Stroke has a high prevalence in Italy, and is the third cause of death worldwide. Hypertension is the most important risk factor contributing to the risk of stroke. The aims of this study were to assess the risk of stroke in a large cohort of hypertensive patients, and to determine the percentage with controlled blood pressure, to establish the contribution of this factor to the risk of stroke.

METHODS

The study involved general practitioners to make it representative of clinical practice. They were asked to recruit 10 consecutive hypertensive patients, treated and untreated. Data collection included a full medical history and a physical examination. The 10-year absolute risk of stroke was calculated by an algorithm derived, with some modification, from the Framingham study.

RESULTS

Most untreated hypertensive patients were grade 1 or 2. In treated hypertensive patients, controlled blood pressure values occurred in 18.4%, the percentage being less in patients with left ventricular hypertrophy and diabetes. In diabetic hypertensive patients the more stringent blood pressure control recommended by the guidelines was achieved in only 3.0% of cases. The average 10-year stroke risk was 17%, a greater risk being more common in elderly patients, diabetic individuals and in those with left ventricular hypertrophy.

CONCLUSION

Current antihypertensive treatment achieved blood pressure control in a limited fraction of hypertensive patients seen by general practitioners. The risk of stroke in hypertensive patients is by no means negligible, which emphasizes the need for more attention to be paid to the prevention of this disease.

The 825C/T polymorphism of G-protein beta3 subunit gene and risk of ischaemic stroke

In this study, we investigated the association of G protein beta3 subunit gene (GNB 3) C825T polymorphism with ischaemic stroke and its subtypes in the Chinese Han population in a large case-control study. A total of 990 ischemic stroke patients and 1124 controls were recruited from six medical centres in China. Genotype was determined by polymerase chain reaction and restriction fragment length polymorphism (RFLP) assay. Logistic regression analysis was performed to identify the independent risk factors for stroke. The frequency of 825T carriers is significantly higher in cerebral thrombosis in male subjects (OR=1.35, 95% CI, 1.01-1.82, P=0.046). After further adjustment with traditional risk factors to stroke, the association is not significant. In conclusion, the GNB3 825T allele is not an independent risk factor to ischaemic stroke in the Chinese population.

Cerebrovascular protection and antihypertensive therapy

PURPOSE OF REVIEW

Our aim is to review the association between blood pressure and stroke and analyse data from randomized controlled trials involving diverse therapies, especially those regarding the renin-angiotensin system. In addition, an overview of stroke pathogenesis is given and its relationship with treatment action mechanisms reviewed.

RECENT FINDINGS

Stroke is a leading cause of death worldwide. In addition, many survivors of stroke suffer different degrees of disability. Because of the ageing of the global population, especially in regions of rapid economic growth, stroke will remain the second leading cause of death and in terms of disability it will be among the five most important causes in both developing and developed countries. High blood pressure is the most important risk factor for stroke, either ischemic or haemorrhagic, and established hypertension is the most prevalent modifiable risk factor. Data from controlled trials of blood-pressure-lowering treatment have demonstrated that treatment considerably lowers the risk of stroke within a few years of starting treatment. However, there exists controversy about the most efficient treatment regimen for primary and secondary prevention of stroke among the different blood-pressure-lowering treatments.

SUMMARY

Debate rages as to whether the benefits of treating high blood pressure are simply determined by the quality of blood-pressure control, or whether the choice of drug therapy adds or detracts from the expected benefits of blood-pressure reduction. The desirable future interventional comparative studies should consent to determine specific effects of drug classes on cardiovascular risk in the absence of the confounding effect of a relevant blood-pressure reduction that may counteract the potential blood-pressure-independent benefits of specific drug classes.

Prevention and treatment of stroke in patients with hypertension

BACKGROUND

Each year, stroke occurs in 30.9 million individuals worldwide and is responsible for approximately 4 million deaths. In the United States, it is the third leading cause of death, occurring with greater frequency than myocardial infarction in patients with hypertension. The greatest burden of stroke, apart from death, is serious long-term physical and mental disability. Stroke survivors often experience physical handicap, depression, and cognitive dysfunction, which together affect their daily functioning, quality of life, and survival. The treatment of stroke is associated with extremely high costs, with stroke-related illnesses responsible for >$49 billion in the United States in 2002. Despite intensive research efforts, few effective treatments are available once stroke has occurred; thus, stroke prevention should be a primary focus for all health care providers.

OBJECTIVE

The purpose of this article was to review the epidemiology and burden of stroke in terms of disability, quality of life, and cost of care, and to summarize the evidence for treatments having therapeutic benefit, with an emphasis on antihypertensive agents.

METHODS

Relevant studies were identified through a MEDLINE search of English-language articles published between 1990 and 2004. The search terms were stroke, epidemiology, economic impact, disability, quality of life, hypertension, drug therapy, and angiotensin II-receptor antagonists. Articles describing major clinical studies, new data, or new mechanisms pertinent to the therapy of stroke were selected for review.

CONCLUSIONS

Identifying and modifying key risk factors is crucial to reducing the morbidity and mortality of stroke. Hypertension is one of the most important risk factors for stroke, and treatment with a variety of antihypertensive agents reduces the risk. Recent evidence suggests that the angiotensin II (ATII)-receptor antagonist losartan may offer advantages beyond blood pressure lowering, including attenuation of the central aortic reflected pressure wave, molecule-specific properties, and neural protective influences on brain ATII type 2 receptors.

Oxidative stress in the chronic phase after stroke

The spontaneous and the stimulated extracellular generation of reactive oxygen species (ROS) by peripheral phagocytes, the blood antioxidant capacity and the degree of oxidative damage were evaluated in patients with severe ischemic and hemorrhagic stroke in the chronic phase of disease. It was found in patients compared to the control group that: (i) the spontaneous phagocyte oxidative activity was enhanced independently of the type of stroke and the time elapsed after stroke onset; (ii) there was no difference in the extracellular ROS generation stimulated by opsonin-dependent and independent receptor mechanisms; (iii) there was no change in the indices of blood antioxidant capacity; (iv) the concentration of plasma lipid peroxides was enhanced regardless of the type of stroke, but it significantly increased over time; and (v) the concentration of blood thiobarbituric acid-reactive material was also enhanced. It was independent of the type of stroke and remained elevated during the whole period studied. We have demonstrated an enhanced spontaneous phagocyte oxidative activity and oxidative damage to lipids in patients in the chronic phase after stroke. The elimination of generated ROS and products of lipid peroxidation from the circulation could prevent the aggravation of chronic vascular injury in patients and could reduce the possibility of a subsequent stroke. This suggests the need for complex therapy, including antioxidant treatment directed to exclude the effects of free radicals, after the oxidative stress of stroke.

The heart, kidney, and brain as target organs in hypertension

The heart, kidney, brain, and arterial blood vessels are prime targets of hypertensive damage. Uncontrolled hypertension accelerates the damage to these organs and results in eventual organ failure and cardiovascular death and disability. Current guidelines for the appropriate treatment and control of hypertension requires an assessment of the presence of target organ damage. When present, evidence of target organ damage determines the urgency and intensity of drug treatment and may also dictate the choice of initial antihypertensive drug class. Thus, evaluation of persons with suspected or established hypertension must include a meticulous search for evidence of target organ damage. Fortunately, treatment with all antihypertensive medications that results in significant BP reductions also reduces fatal and nonfatal hypertensive complications and significantly slows down the progression to organ failure. Because of the important role that adverse activation of the renin-angiotensin-aldosterone system plays in target organ damage, drugs that antagonize this system have provided consistent and compelling proof of organ protection in both primary and secondary prevention of adverse outcomes. The challenge now is to use these and all other antihypertensive agents effectively to control BP to target levels in patients with hypertension. Continued emphasis on the adoption of lifestyle changes for prevention of hypertension in the first place or as adjunctive therapy in hypertensive patients is essential.