Abnormal haemorheology, endothelial function and thrombogenesis in relation to hypertension in acute (ictus < 12 h) stroke patients: the West Birmingham Stroke Project

ANALYSIS OF THE BLOOD HYPERCOAGULATION RISK IN PATIENTS WITH ISCHEMIC ATHEROTHROMBOTIC STROKE DEPENDING OF THE VDR GENE POLYMORPHISMS

OBJECTIVE

Aim: of our study was the analysis of the blood hypercoagulation risk in patients with ischemic atherotrombotic stroke depending of the VDR gene polymorphisms.

PATIENTS AND METHODS

Materials and Methods: Blood of 170 patients with ischemic atherothrombotic stroke (IATS) and 124 healthy individuals (control group) was used for genotyping. Four polymorphisms (FokI, BsmI, ApaI, TaqI) of gene VDR were examined with PCR-RFLP methodology. Statistical analysis was performed by using SPSS-17.0 program.

RESULTS

Results: Among patients with IATS who are carriers of the f/f genotype, FokI polymorphism of VDR gene by high thrombin time and a decrease in the rate of spontaneous fibrinolysis was registered. In individuals with the B/B genotype homozygous for the polymorphic variant, BsmI had significantly lower mean values of prothrombin and thrombin time and increased the rate of spontaneous fibrinolysis. The homozygotes for the A-allele ApaI polymorphism have 2.7 times higher risk of developing blood hypercoagulation than homozygotes for the a-allele was found.

CONCLUSION

Conclusions: Biochemical signs of hypercoagulation syndrome among patients with IATS who are carriers of the f/f genotype of the FokI polymorphic variant and among B/B homozygotes of the BsmI polymorphic variant and homozygotes for the A-allele of the AрaI polymorphism of the VDR gene were registered.

Evaluation of analytic and clinical performance of thrombin-antithrombin complex and D-dimer assay in prognosis of acute ischemic stroke

: To evaluate analytic and clinical performance of plasma thrombin-antithrombin complex (TAT) and D-dimer assay in assessing the severity and outcome of acute ischemic stroke. The prospective study was conducted and extended from January 2018 to December 2018. A total of 236 patients admitted within 24 h after neurologic symptoms onset were recruited. The median TAT and D-dimer levels were significantly higher in the acute ischemic stroke patients than in the controls. The average TAT levels in patients with mild, moderately severe and severe stroke were 1.75 [interquartile ranges (IQR), 1.1-2.6], 3.3 (IQR, 1.8-4.5) and 13.5 (IQR, 7.2-15.3) ng/ml. The D-dimer levels of respective patient groups were 0.39 (IQR, 0.22-0.73), 0.58 (IQR, 0.39-1.25) and 3.59 (IQR, 1.73-4.74) mg/l. With the optimal cut-off TAT level (1.75 ng/ml) determined from receiver operating characteristic analysis, the Area under the curve (AUC), the sensitivity and specificity of TAT for stroke diagnosis were 0.763, 58.1 and 87.8%. The cut-off D-dimer level was 0.38 mg/l and the AUC, the sensitivity and specificity were 0.772, 60.2 and 88.9%. The Area under the receiver operating characteristic curves (AUROCs) and sensitivity in the moderate to severe stroke increased to 0.903 and 86.9% for TAT, and 0.880 and 80.3% for D-dimer, respectively. Age and high TAT level were significant independent risk factors for stroke severity. Age, high initial National Institutes of Health Stroke Scale score and high TAT level were significant independent poor prognostic factors on multivariate analysis. TAT and D-dimer were superior in separating the moderate-to-severe stroke than mild stroke. A high TAT plasma level is an independent predictor for stroke severity and poor prognosis during 1-month follow-up.

Plasma D-Dimer Concentrations and Risk of Intracerebral Hemorrhage: A Systematic Review and Meta-Analysis

Background: The aim of our meta-analysis was to evaluate the association between plasma d-dimer and intracerebral hemorrhage (ICH).

Methods: Embase, Pubmed, and Web of Science were searched up to the date of March 19th, 2018, and manual searching was used to extract additional articles. Standard mean difference (SMD) with 95% confidence intervals (CI) was calculated to evaluate d-dimer levels.

Results: Thirteen studies including 891 ICH patients and 1,573 healthy controls were included. Our results revealed that higher levels of d-dimer were displayed in ICH patients than those in healthy controls (95% CI= 0.98–2.00, p< 0.001). Subgroup analysis based on continent of Asia and Europe, sample size, as well as age in relation to d-dimer levels between ICH patients and healthy controls did not change the initial observation; whereas no differences of d-dimer levels were found between ICH and controls in America.

Conclusions: This meta-analysis revealed that high level of d-dimer is associated with the risk of ICH. Plasma d-dimer is suggested to be a potential biomarker for patients with ICH in Asia and Europe rather than in America. There were no impact of sample size-related differences and age-related diversities on the risk of ICH with respect to d-dimer levels.

Exposure to hypoglycemia and risk of stroke

In the treatment of both type 1 and type 2 diabetes mellitus, maintaining a euglycemic state represents one of the key challenges. Improper dosing and administration of glucose-lowering drugs is associated with an increased risk of recurrent hypoglycemia episodes. In addition, the risk of adverse cardiovascular events in diabetic patients, particularly myocardial infarctions and strokes, is well established. Current research indicates a potential link between the baseline risk of cardio/cerebrovascular events in diabetic patients and exposure to hypoglycemia. In this review of the literature, we aim to determine if a relationship exists between recurrent hypoglycemia and adverse neurovascular events.

IMM-H004, a coumarin derivative, attenuated brain ischemia/reperfusion injuries and subsequent inflammation in spontaneously hypertensive rats through inhibition of VCAM-1

We studied the effect of IMM-H004 in treating brain I/R injury in spontaneously hypertensive rats and showed that IMM-H004 could efficiently ameliorate neurological defects and infarct volume in a time and dose dependent manner.

Intravenous immunoglobulin increases plasma viscosity without parallel rise in blood pressure

WHAT IS KNOWN AND OBJECTIVE

Intravenous immunoglobulin (IVIg) is a commonly used therapy for autoimmune disease, but may cause chronic hypertension and thrombosis. We determined whether: (i) IVIg systematically affects blood pressure in the short term; (ii) acute changes in plasma viscosity because of IVIg correlate with blood pressure effects; (iii) effects of IVIg on acute blood pressure are related to baseline blood pressure or hypertension status and (iv) IVIg influences plasma markers of inflammation, anticardiolipin antibodies and homocysteine as additional putative prothrombotic risk factors.

METHODS

Twenty adults with autoimmune neurological disease who received a course of IVIg were evaluated immediately before and after each infusion, on every day of the course. Blood pressure, pulse and the following haematological parameters were determined: plasma viscosity, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), haematocrit, fibrinogen, interleukin-6 (IL-6), homocysteine and anticardiolipin positivity.

RESULTS

Intravenous immunoglobulin caused both acute and cumulative rises in plasma viscosity across a treatment course, but no concordant changes in blood pressure. There was also no correlation between individual blood pressure changes and viscosity, baseline blood pressure or hypertension status. Levels of IL-6 rose across the course of therapy, but the acute-phase reactants CRP and fibrinogen did not. One patient developed anticardiolipin antibodies during therapy.

WHAT IS NEW AND CONCLUSION

Individual courses of IVIg do not systematically raise blood pressure. Where IVIg is found to cause hypertension, this does not appear to be due to a direct effect of IVIg on plasma viscosity.

Association between homocysteine and endothelial dysfunction markers in stroke disease

BACKGROUND

Evidence shows that there is an increase in concentrations of markers of endothelial dysfunction immediately following acute ischaemic stroke. Several studies suggest that endothelial dysfunction may be partly caused by oxidation related to the effects of raised total plasma homocysteine.

OBJECTIVE

The aim of this study was to measure changes in total plasma homocysteine and markers of endothelial dysfunction in stroke disease within a known period of time post infarct.

SUBJECTS AND METHODS

We studied 40 acute ischaemic stroke patients (mean age +/- SD, 50.2 +/- 9.5 years) and 42 hospitalised non-stroke patients (mean age, 44.3 +/- 14.9 years). Fasting venous blood was obtained within 24 h, 3 days and 7 days after the stroke onset and hospitalisation for non-stroke patients for measurements of total plasma homocysteine, markers of endothelial dysfunction including intracellular adhesion molecule (i-CAM), vascular cell adhesion molecule-1 (v-CAM) and leukocyte adhesion molecule-1 (E-selectin) and C-reactive proteins (CRPs).

RESULTS

We found no significant differences in baseline total plasma homocysteine, E-selectin, v-CAM, vitamin B(12), and folate concentrations between ischaemic stroke patients and non-stroke controls. i-CAM concentrations were significantly higher and CRPs non-significantly lower at baseline in stroke patients compared with controls. Although all endothelial dysfunction markers increased significantly during the study period, the rise in E-selectin levels was less than that seen in i-CAM, and v-CAM. Total plasma homocysteine concentrations showed positive correlations with creatinine (r = 0.537; P < 0.02), and inverse correlations with both vitamin B(12) (r = -0.560; P < 0.001) and folate (r = -0.469; P < 0.002); however, there were no significant correlations between total plasma homocysteine or B-vitamins and markers of endothelial dysfunction in ischaemic stroke patients or controls.

CONCLUSIONS

We found evidence of an increase in markers of endothelial dysfunction following acute ischaemic stroke but this had no relationship with total plasma homocysteine concentrations.

Platelet function following acute cerebral ischemia

BACKGROUND

Studies have previously identified increased levels of platelet activation following acute ischemic stroke. In order to evaluate new antiplatelet agents and their combinations, there is a need for accurate measures of platelet activation.

METHODS

Blood was taken from 17 patients within 24 hours of an acute ischemic stroke, and then at 3, 7, 14 and 42 days. For comparison, a group of 18 stable arteriopaths had identical tests performed. Platelet aggregation was measured using a free platelet counting technique, and platelet surface P-selectin and monocyte platelet aggregates (MPAs) were measured using flow cytometry. Soluble P-selectin and D-dimers were measured by an enzyme linked immune assay.

RESULTS

The initial level of MPAs was significantly raised in the stroke patients compared with the stable patients (p = 0.04, 14.2% vs. 9.3%); however, this difference was not significantly higher than later study points (14.2%, 10.1%, 9.3%, 11.9%, 11.3%; days 1, 3, 7, 14 and 42 respectively. Day 1 vs. day 7 p = 0.07 ANOVA). No changes in P-selectin or platelet aggregation were identified. D-dimer levels were significantly higher on day 7 than day 42 (p < 0.01), and fibrinogen levels were elevated on both days 3 and 14 compared with day 42. Fibrinogen levels were not elevated compared with stable patients.

CONCLUSIONS

MPA levels are elevated following an acute ischemic stroke compared to stable patients, but no significant change was seen with other platelet markers. This study suggests MPAs are a more sensitive marker of platelet activation than either P-selectin or aggregation.

Improving abnormal hemorheological parameters in aging guinea pigs by water-soluble extracts of Salvia miltiorrhiza Bunge

Salvia miltiorrhiza Bunge, known as Danshen in Chinese traditional medicine is effective at promoting blood circulation and removing (or decreasing) blood stasis. In the present study, we selected aging, 24-month-old guinea pigs as the animal experimental models and fed them a diet containing 75, 100 or 150 mg/(kg day) of water-soluble extract components of Salvia miltiorrhiza Bunge (WSm) for 28 days, respectively, in order to evaluate the effects of WSm on their abnormal hemorheological parameters. The results showed that the blood biochemical parameters of the aging guinea pigs remained unaffected by orally given WSm compared to the controls, except that the fibrinogen levels of the group fed the high dose of WSm (150 mg/(kg day)) decreased. Aging guinea pigs fed a low dose of WSm (75 mg/(kg day)) showed no significant difference in hemorheological parameters. However, feeding of WSm at 100 mg/(kg day) (medium dose), significantly reduced erythrocyte membrane MDA levels, which probably increased erythrocyte deformability and decreased erythrocyte flow resistance, though no improvement in erythrocyte aggregation, blood viscosity, and blood viscoelasticity could be observed. Furthermore, when the dose reached 150 mg/(kg day) of WSm (high dose), a significant decrease in whole blood viscosity was observed at high, medium and low shear rates. Blood viscosity and viscoelasticity exhibited significant improvement in oscillatory measurements. Also, we found that the oxygen transport efficiency of whole blood increased.

Improving Effects of Epigallocatechin-3-Gallate on Hemorheological Abnormalities of Aging Guinea Pigs

BACKGROUND

Epigallocatechin-3-gallate (EGCG) is the most potent antioxidant of all the green tea catechins. The objective of the present study was to find out whether it improved the age-induced hemorheological abnormalities or not.

METHODS AND RESULTS

Twenty-four-month-old aging guinea pigs were used to test the effects of EGCG on hemorheological properties. Orally feeding EGCG at 30 mg x kg(-1) x day (-1) for 28 days resulted in a decrease in erythrocyte membrane malondialdehyde, and further improved erythrocyte deformability and blood viscosity at high and middle shear rates. In addition, it also significantly reduced erythrocyte aggregation, and improved blood viscosity at low shear rates and viscoelasticity at oscillatory flow. Consequently, efficiency of blood oxygen transport in aged guinea pigs increased after administration with EGCG.

CONCLUSIONS

Orally feeding EGCG 30 mg x kg(-1) x day(-1) for 28 days significantly improves the abnormal hemorheological parameters. These results suggest that EGCG has considerable potential as a substantial component for the development of new drugs or functional foods in improving the age-induced hemorheological abnormalities.

Coagulation and inflammatory markers in Alzheimer's and vascular dementia

Alzheimer's disease is classified as a degenerative dementia while vascular dementia is known to be associated with atherothrombosis and classical vascular risk factors. However, over the last decade, there is increasing evidence of the role of haemostatic factors and inflammatory mechanisms in the pathogenesis of Alzheimer's disease. Serum markers of hypercoagulability and markers of inflammation could lead to thrombosis, accelerated atherogenesis and resulting dementia of both Alzheimer's and vascular dementia. In this case control study, we studied these serum markers of coagulation and inflammation in patients suffering from dementia.

Hemostatic Function and Progressing Ischemic Stroke

BACKGROUND AND PURPOSE

Early clinical progression of ischemic stroke is common and is associated with increased risk of death and dependency. We hypothesized that activation of the coagulation system is an important contributor in some cases of deterioration. We aimed to characterize alterations in circulating hemostatic markers in patients with progressing stroke.

METHODS

Consecutive acute ischemic stroke admissions were recruited. Progressing stroke was defined by deterioration in components of the Scandinavian Stroke Scale. Hemostatic markers (coagulation factors VIIc, VIIIc, and IXc, prothrombin fragments 1+2 [F1+2], thrombin-antithrombin complexes [TAT], D-dimer, fibrinogen, von Willebrand factor [vWF] and tissue plasminogen activator) were measured within 24 hours of symptom recognition.

RESULTS

Fifty-four (25%) of the 219 patients met criteria for progressing stroke. F1+2 (median 1.28 versus 1.06 nmol/L, P=0.01), TAT (5.28 versus 4.07 microg/L, P<0.01), D-dimer (443 versus 194 ng/mL, P<0.001) and vWF (216 versus 198 IU/dL, P<0.05) levels were higher in these patients than in stable/improving patients. In logistic regression analysis, with all important clinical and laboratory variables included, only natural log D-dimer (odds ratio [OR]: 1.87; 95% confidence interval [CI]: 1.38 to 2.54; P=0.0001) and mean arterial blood pressure (OR: 1.26 per 10 mm Hg change; 95% CI: 1.05 to 1.51; P=0.01) remained independent predictors of progressing stroke.

CONCLUSIONS

There is evidence of excess thrombin generation and fibrin turnover in patients with progressing ischemic stroke. Measurement of D-dimer levels can identify patients at high risk for stroke progression. Further research is required to determine whether such patients benefit from acute interventions aimed at modifying hemostatic function.

Predictors of Early Neurological Deterioration after Ischaemic Stroke: A Case-Control Study

BACKGROUND

Early neurological deterioration after ischaemic stroke (stroke in progression) is reported to be common and associated with poor outcome or death. The causes of progressing stroke are, however, uncertain.

OBJECTIVE

To determine whether prior drug treatment (with anticoagulant or antiplatelet agents) or early adverse physiological features (pyrexia, hypoxia, dehydration or hyperglycaemia) are associated with progressing ischaemic stroke.

METHODS

The study used a case-control design. From a database of 873 consecutive acute stroke admissions, 196 cases of progressing ischaemic stroke (defined by point deterioration in components of the Scandinavian Stroke Scale or death over the first 72 h after hospital admission) were matched to 196 controls on the basis of age and stroke type. Univariate and conditional logistic regression techniques were used to explore predictors of progressing stroke.

RESULTS

Cases and controls were well matched for baseline stroke severity. Warfarin use prior to admission was associated with a reduced risk of progressing stroke [odds ratio (OR) 0.10, p = 0.005]. Prior antiplatelet use was not related. A previous history of diabetes (OR 2.11, p = 0.039) and elevated systolic blood pressure on admission (OR 1.01 for each 1 mm Hg rise, p = 0.017) predicted progressing stroke. Although there were no differences in time to presentation or to brain imaging, a visible causative lesion on CT scanning was more common in the progressing stroke group (OR 2.30, p = 0.022). We found no evidence that adverse physiological features were associated with progressing stroke. Outcomes were worse in the progressing stroke group with 70% being dead or dependent by 30 days compared to 55% in the control group (p = 0.002).

CONCLUSION

Prior warfarin use may be protective against progressing ischaemic stroke. A previous history of diabetes along with elevated admission systolic blood pressure predict deterioration. We found no evidence for an association between adverse physiological features and progressing stroke.

Circadian variation of blood pressure and endothelial function in patients with essential hypertension:a comparison of dippers and non-dippers

OBJECTIVES

The purpose of this study was to evaluate the relationship between the circadian blood pressure (BP) rhythm and endothelial function in patients with essential hypertension.

BACKGROUND

Hypertension is associated with alterations in resistance artery endothelial function. Patients with a non-dipper circadian pattern of BP have a greater risk of cerebrovascular and cardiovascular complications than do patients with a dipper circadian pattern.

METHODS

We evaluated the forearm blood flow (FBF) response to intra-arterial acetylcholine (ACh), an endothelium-dependent vasodilator, and isosorbide dinitrate (ISDN), an endothelium-independent vasodilator, infusion in 20 patients with non-dipper hypertension and 20 age- and gender-matched patients with dipper hypertension. The FBF was measured using a mercury-filled Silastic strain-gauge plethysmograph.

RESULTS

The 24-h systolic BP, as well as nocturnal systolic and diastolic BPs were higher in non-dipper patients than in dipper patients. The 24-h urinary excretion of nitrite/nitrate and cyclic guanosine monophosphate was lower in non-dippers than in dippers. The response of FBF to ACh was smaller in non-dippers than in dippers (25.1 +/- 3.1 vs. 20.2 +/- 3.0 ml/min/100 ml tissue, p < 0.05). The FBF response to ISDN was similar in dippers and non-dippers. The FBF response to ACh was similar in the two groups following intra-arterial infusion of the nitric oxide (NO) synthase inhibitor N(G)-monomethyl-L-arginine.

CONCLUSIONS

These findings suggest that endothelium-dependent vasodilation is blunted through a decrease in NO release in non-dippers compared with patients who have dipper hypertension.

Sequential alterations in haemorheology, endothelial dysfunction, platelet activation and thrombogenesis in relation to prognosis following acute stroke: The West Birmingham Stroke Project

Abnormalities of haemorheology (plasma viscosity, fibrinogen), endothelial function [von Willebrand factor (vWf)], platelet activation (soluble P-selectin) and thrombogenesis [plasminogen activator inhibitor (PAI), and fibrin D-dimer] are common in cardiovascular disease. We investigated changes in these markers in 86 patients (58 males) presenting with acute stroke (all age < 75 years, with ictus < 12 h), and sequential changes at six time points (baseline on admission, 48 h, 1 week, 2 weeks, 3 months and 6 months following the onset of stroke). Baseline plasma viscosity, haematocrit, fibrinogen, vWf, PAI, soluble P-selectin and fibrin D-dimer levels were increased in the acute stroke patients compared with 35 age-matched and sex-matched controls. Following admission, there were significant increases in haematocrit at 2 weeks, vWf at 48 h and 1 week, fibrinogen at 1 week, PAI at 48 h and 1 and 2 weeks, soluble P-selectin at 48 h, and fibrin D-dimer at 48 h and 1 week following admission. Using univariate 'time to event' analysis, high (> median) mean age (log-rank test, P = 0.0262), diastolic blood pressure (P = 0.01), haematocrit (P = 0.0234), PAI-1 (P = 0.0066) and fibrin D-dimer levels (P = 0.0356) were associated with a shortened event-free survival. Using a multivariate Cox survival analysis, only PAI-1 levels remained an independent predictor of survival (P = 0.0349). We conclude that acute stroke patients have marked baseline abnormalities of haemorheology, endothelial disturbance, thrombogenesis, platelet activation and abnormal fibrinolysis, with further changes over the subsequent follow-up period. Abnormal thrombogenesis and fibrinolysis may significantly influence survival in patients with acute stroke. These changes may have potential implications for the pathogenesis of stroke and its complications, although the possibility remains that we are documenting an acute phase response that previous studies, which included stroke patients with a wide time range since ictus onset, have neglected to consider.