Advances in primary stroke prevention

Priorities to reduce the burden of stroke in Latin American countries

The large and increasing burden of stroke in Latin American countries, and the need to meet the UN and WHO requirements for reducing the burden from non-communicable disorders (including stroke), brought together stroke experts and representatives of the Ministries of Health of 13 Latin American countries for the 1st Latin American Stroke Ministerial meeting in Gramado, Brazil, to discuss the problem and identify ways of cooperating to reduce the burden of stroke in the region. Discussions were focused on the regional and country-specific activities associated with stroke prevention and treatment, including public stroke awareness, prevention strategies, delivery and organisation of care, clinical practice gaps, and unmet needs. The meeting culminated with the adoption of the special Gramado Declaration, signed by all Ministerial officials who attended the meeting. With agreed priorities for stroke prevention, treatment, and research, an opportunity now exists to translate this Declaration into an action plan to reduce the burden of stroke.

Helicobacter pylori infection contributes to high risk of ischemic stroke: evidence from a meta-analysis

Chronic infection of Helicobacter pylori (H. pylori) in ischemic stroke (IS) incidence has been previously studied in several publications; however, conflicting results have been reported. A meta-analysis was used to assess whether chronic infection of H. pylori was associated with risk of IS, and which of the following was more effective for predication of IS risk, antibody IgG of H. pylori (anti-H. pylori IgG), antibody IgG of cytotoxin-associated gene-A (anti-Cag A IgG) or the (13)C-urea breath test. We searched the databases of Medline and Embase, and latest update was January 1, 2012. Case-control studies were considered to be eligible. The odds ratio (OR) and 95 % confidence interval (95 % CI) were calculated using the random-effect model. A total of 13 studies including 4,041 participants were included in this meta-analysis. Of these studies, ten, four and four studies were for anti-H. pylori IgG, anti-Cag A IgG and the (13)C-urea breath test, respectively. Combined analysis indicated that positive anti-H. pylori IgG, anti-Cag A IgG and (13)C-urea breath test were significantly associated with increased risk of IS, respectively, and positive anti-Cag A IgG was more effective for predication of IS risk [OR (95 % CI) = 1.60 (1.21-2.11), P (heterogeneity) = 0.001 for positive versus negative anti-H. pylori IgG; 2.33 (1.76-3.09), P (heterogeneity) = 0.71 for positive versus negative anti-Cag A IgG and 1.65 (1.11-2.47), P (heterogeneity) = 0.17 for positive versus negative (13)C-urea breath test]. In addition, we found that positive anti-H. pylori IgG was closely associated with risk of IS caused by atherosclerosis and small artery disease, but not for cardioembolic IS. This meta-analysis indicated that chronic H. pylori infection was significantly associated with an increased risk of IS, especially for non-cardioembolic IS. Compared with anti-H. pylori IgG and the (13)C-urea breath test, anti-Cag A IgG seemed more effective for prediction of risk of IS.

Cerebrovascular disease in diabetes mellitus: the role of carotid intima-media thickness

BACKGROUND AND PURPOSE

Cerebrovascular disease in diabetes appears to be less considered than coronary and peripheral disease, the reason being the intrinsic difficulty in finding available diagnostic tools for its early identification. Among these, carotid artery intima-media thickness (cIMT) represents the simplest measurable parameter for pre-atherosclerotic lesions in extra-cranic arteries.

METHODS

The role of cIMT as a surrogate marker of cerebral atherosclerosis and predictor of stroke, its relationship to microangiopathy and chronic inflammation, along with its role as an outcome parameter in anti-hyperglycemic therapeutical intervention trials in type 2 and 1 diabetes mellitus are discussed in this paper.

RESULTS AND CONCLUSIONS

Carotid IMT is increased in diabetes. It is an independent predictor of stroke, in particular of the ischemic subtype, and of stroke recurrence in diabetic, as well as in non-diabetic populations. A possible role of cIMT as a predictor of microangiopathy has also been suggested, but it needs further investigation. A weak association with chronic inflammation has been demonstrated in diabetic patients. Carotid IMT has been successfully employed as an outcome parameter for several anti-hyperglycemic therapeutic trials. However data on cIMT as a predictor of cerebrovascular disease are scarce in diabetic patients, particularly in type 1 diabetes, and more studies are needed to define the risk of cerebrovascular disease in diabetic patients.

Prognostic value of QT parameters in patients with acute hemorrhagic stroke: a prospective evaluation with respect to mortality and post-hospitalization bed confinement

BACKGROUND

This prospective study was performed to evaluate the prognostic prediction value of QT parameters and clinical characteristics exhibited by patients with acute hemorrhagic stroke at the time of presenting to the emergency department (ED).

METHODS

One hundred and sixty-six patients admitted to the ED of Taipei Veterans General Hospital from January 2006 to October 2006 because of acute hemorrhagic stroke were enrolled. Glasgow Coma Scale (GCS) scores between 3 and 8 were taken to indicate severe neurologic deficits. QT parameters (QT max, QT min, QT dispersion, QTc max, QTc min, QTc dispersion) and other pertinent clinical variables were determined on admission. Logistic regression model was applied to evaluate prognostic prediction values.

RESULTS

Mortality was higher among stroke patients with low GCS scores (p < 0.01). Leukocyte counts and systolic blood pressures were significantly higher among non-surviving patients (p = 0.04). No association was found between QT parameters and mortality (all p > 0.05). Among survivors, post-hospitalization bed confinement was required for those significantly older (p = 0.01) and those with higher QT max and QTc max values in multivariate analyses (p = 0.04 and p < 0.01, respectively).

CONCLUSION

Low GCS scores, increased leukocyte counts, and elevated systolic blood pressures predict increased mortality for subjects with acute hemorrhagic stroke. Advanced age and prolongations in QTc and QT max at the time of stroke predicted poor functional recovery for these subjects.

Lipocalin-prostaglandin D synthase is a critical beneficial factor in transient and permanent focal cerebral ischemia

Prostaglandin D(2) (PGD(2)) is the most abundant prostaglandin produced in the brain. It is a metabolite of arachidonic acid and synthesized by prostaglandin D(2) synthases (PGDS) via the cyclooxygenase pathway. Two distinct types of PGDS have been identified: hematopoietic prostaglandin D synthase (H-PGDS) and lipocalin-type prostaglandin D synthase (L-PGDS). Because relatively little is known about the role of L-PGDS in the CNS, here we examined the outcomes in L-PGDS knockout and wild-type (WT) mice after two different cerebral ischemia models, transient middle cerebral artery (MCA) occlusion (tMCAO) and permanent distal middle cerebral artery occlusion (pMCAO). In the tMCAO model, the MCA was occluded with a monofilament for 90 min and then reperfused for 4 days. In the pMCAO model, the distal part of the MCA was permanently occluded and the mice were sacrificed after 7 days. Percent corrected infarct volume and neurological score were determined after 4 and 7 days, respectively. L-PGDS knockout mice had significantly greater infarct volume and brain edema than did WT mice after tMCAO (P<0.01). Similarly, L-PGDS knockout mice showed greater infarct volume and neurological deficits as compared to their WT counterparts after pMCAO (P<0.01). Using the two models enabled us to study the role of L-PGDS in both early (tMCAO) and delayed (pMCAO) ischemic processes. Our findings suggest that L-PGDS is beneficial for protecting the brain against transient and permanent cerebral ischemia. These results provide a better understanding of the role played by the enzymes that control eicosanoid synthesis and how they can be utilized as potential targets to prevent damage following either acute or potentially chronic neurological disorders.

Drug therapy for the secondary prevention of stroke in hypertensive patients: current issues and options

Hypertension is the major risk factor for ischaemic and haemorrhagic clinical strokes as well as for silent brain infarcts with a continuous association between both systolic and diastolic blood pressures. Epidemiological data highlight the increasing burden to come over the next decades. Without any doubt, antihypertensive treatment is the most important therapy to reduce the risk of stroke by approximately 30-40%. International guidelines recommend antihypertensive treatment for primary prevention with evidence level A. Recurrent strokes or transient ischaemic attack (TIA) are an important practical, clinical and economic problem, and have a major impact on the development of vascular dementia. All stroke patients and patients with TIA have to be regarded as very high-risk patients. Hypertension increases the risk of recurrent strokes. Only limited data directly address the role of blood pressure treatment among individuals with stroke or TIA. There is a general lack of definitive data regarding when to start antihypertensive treatment in the initial phase, and treatment of hypertension in the acute period after stroke is still under debate. Experimental and clinical data suggest that reducing the activity of the renin-angiotensin aldosterone system (RAAS) may have beneficial effects beyond the lowering of blood pressure. There is increasing evidence of cerebroprotective effects for medication influencing the RAAS, such as angiotensin receptor antagonists or ACE inhibitors. The MOSES study showed for the first time superiority of an angiotensin receptor antagonist compared with a calcium channel antagonist in antihypertensive treatment for secondary stroke prevention. Optimal blood pressure range in secondary prevention seems to be 120-140/80-90 mm Hg, but questions about a J- or U-shaped curve are still not answered sufficiently. The effects of additional antihypertensive treatment in the evening for stroke patients with 'non-dipping' blood pressure need to be investigated.Currently, the most important goal in primary and secondary prevention of stroke is a strict normotensive blood pressure control. Antihypertensive treatment is recommended for both prevention of recurrent stroke and prevention of other vascular events in individuals who have had an ischaemic stroke or TIA (class I, level of evidence A). Many open questions remain and funding of stroke research needs to be increased in the near future.