Andrew J. Catto

Platelet GP IIIa PlA and GP Ib Variable Number Tandem Repeat Polymorphisms and Markers of Platelet Activation in Acute Stroke

A number of polymorphisms of the platelet glycoprotein (GP) Ib-V-IX and IIb/IIIa complexes have been described, and the PlA polymorphism of GP IIIa has been associated with coronary thrombosis. We determined the levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) and the genotype distributions of PlA and a variable number tandem repeat (VNTR) polymorphism of GP 1b in subjects with acute stroke (n=609) and healthy control subjects (n=435). Levels of beta-TG were higher in patients both initially (47.4 [44.7 to 50.2] ng/mL, P<0.0001) and after 3 months (42.9 [40.3 to 45.7] ng/mL, P=0.03) compared with control subjects (39.4 [37.7 to 41.2] ng/mL). Initial levels of beta-TG were significantly higher in those who subsequently died (58.7 [52.3 to 65.8] ng/mL) compared with those still alive (42.7 [40.1 to 45.5] ng/mL, P<0.0001). In a logistic regression model, beta-TG remained an independent predictor of poststroke mortality, with an odds ratio for an increase in 10 ng/mL of 1.12 (1.03 to 1.21, P=0.006). In subjects who had never smoked, there was a significant difference in the genotype distributions of patients with atherothrombotic stroke (A1/A1=147, A1/A2=70, and A2/A2=2) compared with controls (A1/A1=165, A1/A2=47, and A2/A2=5, P=0.03). The PlA distribution of subjects with atherothrombotic stroke before the age of 50 years (A1/A1=19 and A1/A2+A2/A2=18) was also significantly different from age- and sex-matched controls (A1/A1=54 and A1/A2+A2/A2=20, P=0.02). We found no association of VNTR with stroke or poststroke mortality. These data indicate that there is a persistent state of enhanced platelet activation in subjects with acute stroke, which is associated with poststroke mortality. The increased frequency of the PlA2 allele in young subjects with atherothrombotic stroke lends further support for a role of the PlA polymorphism in acute thrombosis.

Factor XIII Val 34 Leu A Novel Association With Primary Intracerebral Hemorrhage

BACKGROUND AND PURPOSE A common G-to-T point mutation (Val 34 Leu) in exon 2 of the alpha-subunit of the factor XIII is strongly negatively associated with the development of myocardial infarction. This result suggests that factor XIII Val 34 Leu is interfering with the formation of cross-linked fibrin. The role of factor XIII Val 34 Leu in the pathogenesis of cerebral infarction and primary intracerebral hemorrhage is unknown. METHODS Six hundred twelve patients with acute stroke, defined by World Health Organization criteria and cranial CT, and 436 age-matched control subjects free of cerebrovascular disease were genotyped for the factor XIII Val 34 Leu mutation. Venous blood was drawn for the determination of hemostatic variables and lipids. Factor XIII genotype was determined through a single-stranded conformational polymorphism technique and plasminogen activator inhibitor (PAI)-1 4G/5G promoter genotype by allele-specific polymerase chain reaction. RESULTS The mutation was more frequent in patients with primary intracerebral hemorrhage (n=62) (54.8%; P=.05) than in control subjects (41.7%) or in patients with cerebral infarction (n=529) (46.5%; P=.22). There was no relationship between PAI-1 levels and the PAI-1 4G/5G genotype. CONCLUSIONS There was a slightly higher incidence of factor XIII Val 34 Leu in patients with PICH. This may be related to impaired cross-linking of fibrin and/or coagulation proteins.

Factor V Leiden Gene Mutation and Thrombin Generation in Relation to the Development of Acute Stroke

To determine the prevalence of the factor V Leiden gene mutation in relation to the phenotypes of cerebral infarction and cerebral hemorrhage, we studied 386 randomly selected cases of acute stroke and 247 control subjects. Factor V genotype was determined by amplification of a 267-bp sequence of exon/intron 10 of the factor V gene. Levels of prothrombin fragment F(1 + 2), a marker of thrombin generation, were determined in both acute and convalescent stroke and related to factor V genotype. Prothrombin fragment F(1 + 2) was assessed by using an enzyme-linked immunosorbent assay. Sixteen stroke cases (4.1%) were identified as having the mutation compared with 14 (5.6%) control subjects. Prothrombin fragment F(1 + 2) levels were estimated in 191 cases and found to be elevated both acutely and after 3 months, but they were not related to factor V genotype. Prothrombin fragment F(1 + 2) is elevated in acute stroke and requires further evaluation in relation to cerebrovascular disease. These results suggest that the factor V Leiden gene mutation is not a risk factor for arterial thrombosis causing stroke.

Angiotensin-Converting Enzyme Insertion/Deletion Polymorphism and Cerebrovascular Disease

BACKGROUND AND PURPOSE There is evidence that an allelic variation in the angiotensin-converting enzyme (ACE) gene may confer an increased risk of vascular disease. The roles of the ACE insertion/deletion polymorphism and circulating ACE levels are unknown in cerebrovascular disease. METHODS We studied an insertion/deletion polymorphism within intron 16 of the ACE gene by polymerase chain reaction and plasma ACE activity in 467 cases of stroke, the pathological type of which was established by cranial CT, and 231 control subjects. ACE genotype and activity were related to stroke type and mortality at 4 weeks and 3 months. RESULTS No difference in genotype frequency was observed between all subjects with stroke and control subjects or between control subjects and subjects with cerebral infarction or cerebral hemorrhage. Plasma ACE activity was significantly lower in stroke patients at presentation (64.1 IU/L) than in control subjects (79.6 IU/L; P<.0001). Twenty-one patients (4.5%) with cerebral infarction died within 4 weeks and 56 patients (12%) within 3 months. These patients had significantly lower plasma ACE activity than patients who survived. There was some evidence that risk of death within 4 weeks increased with the number of D alleles (P=.02). Among survivors, plasma ACE activity showed a mean increase of 6.9 IU/L (95% confidence interval, 3.0 to 10.8) between levels at presentation and at 3 months (73.6 IU/L), the latter being similar to ACE activity in control subjects. CONCLUSIONS Low ACE activity at sroke presentation and possession of the D allele may be associated with increased risk of early death from acute cerebral infarction.

European Stroke Initiative Recommendations for Stroke Management

This article summarises recommendations for acute management of stroke by the European Stroke Initiative (EUSI), on behalf of the European Stroke Council (ESC), the European Neurological Society (ENS), and the European Federation of Neurological Societies (EFNS).

Predictive Variables for Mortality After Acute Ischemic Stroke

Background and Purpose— Stroke is a major healthcare issue worldwide with an incidence comparable to coronary events, highlighting the importance of understanding risk factors for stroke and subsequent mortality. Methods— In the present study, we determined long-term (all-cause) mortality in 545 patients with ischemic stroke compared with a cohort of 330 age-matched healthy control subjects followed up for a median of 7.4 years. We assessed the effect of selected demographic, clinical, biochemical, hematologic, and hemostatic factors on mortality in patients with ischemic stroke. Stroke subtype was classified according to the Oxfordshire Community Stroke Project criteria. Patients who died 30 days or less after the acute event (n=32) were excluded from analyses because this outcome is considered to be directly attributable to the acute event. Results— Patients with ischemic stroke were at more than 3-fold increased risk of death compared with the age-matched control cohort. In multivariate analyses, age, stroke subtype, atrial fibrillation, and previous stroke/transient ischemic attack were predictive of mortality in patients with ischemic stroke. Albumin and creatinine and the hemostatic factors von Willebrand factor and &bgr;-thromboglobulin were also predictive of mortality in patients with ischemic stroke after accounting for demographic and clinical variables. Conclusions— The results indicate that subjects with acute ischemic stroke are at increased risk of all-cause mortality. Advancing age, large-vessel stroke, atrial fibrillation, and previous stroke/transient ischemic attack predict mortality; and analysis of albumin, creatinine, von Willebrand factor, and &bgr;-thromboglobulin will aid in the identification of patients at increased risk of death after stroke.

Gender-Specific Associations of the Fibrinogen Bβ 448 Polymorphism, Fibrinogen Levels, and Acute Cerebrovascular Disease

Fibrinogen is an independent risk factor for the development of stroke. Factors influencing circulating levels of fibrinogen include age, smoking, gender, and genetic factors. The aim of this study was to determine the relationship between a polymorphism at position 448 of the B beta fibrinogen gene, fibrinogen levels, gender, and the risk of stroke. Fibrinogen levels were determined in 305 patients with stroke, taken within 10 days of the acute event and 3 months later, and in 197 control subjects. Initial fibrinogen levels in patients (4.49 g/L) were significantly higher than at 3 months (3.85 g/L, P < .0001), consistent with resolution of the acute-phase response. At 3 months, levels were only significantly higher than for control subjects in the male patients (3.86 g/L versus 3.31 g/L, P < .0001). Fibrinogen levels were associated with B beta 448 genotype in male patients at 3 months (1/1 = 3.62 g/L, 1/2 + 2/2 = 4.27 g/L, P = .01). There was a significant difference in the genotype distribution in female patients and control subjects (patients: 1/1 = 95, 1/2 = 34, 2/2 = 6; control subjects: 1/1 = 61, 1/2 = 50, 2/2 = 3, P = .008). These data suggest that the mechanisms linking fibrinogen and the development of cerebrovascular disease are different in males and females. In male patients, the increase in fibrinogen levels may be influenced by environmental factors, while in females there may be a functional difference in the fibrinogen molecule unrelated to fibrinogen levels.

Association of the α-Fibrinogen Thr312Ala Polymorphism With Poststroke Mortality in Subjects With Atrial Fibrillation

BACKGROUND The alpha-fibrinogen Thr312Ala polymorphism occurs in close proximity to several sites important for factor XIIIa-dependent cross-linking, which raises the possibility that it affects fibrin clot stability. METHODS AND RESULTS We determined the association of this polymorphism with ischemic stroke, stroke subtype, and poststroke mortality. There was no significant difference in the genotype distributions of patients with acute ischemic stroke (n=519) and healthy control subjects (n=423), nor was there any association of this polymorphism with stroke subtype. In a Cox regression model, a significant interaction between Thr312Ala and atrial fibrillation was identified in relation to poststroke mortality (P=0.002). In subjects in sinus rhythm (n=418), there was no difference according to genotype in the proportion of subjects who survived (approximately 60% in each group), whereas in subjects with atrial fibrillation (n=101), there was decreased survival in those possessing the A allele (TT=42.1%, TA=18%, AA=0%). CONCLUSIONS The Thr312Ala polymorphism may give rise to an increased susceptibility for embolization of intra-atrial clot, and these findings could have important implications for identifying subjects most at risk of developing thromboembolic complications.

Angiotensin converting enzyme insertion/deletion genotype is associated with leukoaraiosis in lacunar syndromes

Objectives: Pathological and clinical data suggest that patients presenting with ischaemic lacunar syndromes may be a heterogenous group. Those with isolated lacunar infarction are thought to have localised atherosclerosis whereas in those with coexisting leukoaraiois a distinct diffuse small vessel vasculopathy may be the predominant underlying pathology. The ACE insertion/deletion (I/D) polymorphism is an important candidate gene in ischaemic cerebrovascular disease but, where lacunar stroke specifically has been examined, there have been discrepant reports concerning a possible association. It was hypothesised that the influence of the ACE gene may be different among the two subgroups of ischaemic lacunar stroke reflecting the heterogeneity of the small vessel disease phenotype. Methods: Eighty four consecutive patients presenting with classic lacunar syndromes were studied. All had acute cranial CT to exclude primary intracerebral haemorrhage and these were subsequently assessed for the presence and extent of leukoaraiosis. All patients were genotyped for the ACE insertion/deletion polymorphism. Results: There was a significant difference in the distribution of ACE genotype with the DD genotype occurring more often in patients with leukoaraiosis and the II and ID genotypes occurring more often among those in whom this was absent (χ2=9.06, p=0.01). In a logistic regression model the ACE DD genotype remained as an independent predictor for the presence of leukoaraiosis (p=0.02) in patients presenting with classic lacunar syndromes. Conclusion: This study supports the hypothesis that there may be different types of small vessel disease in patients with classic lacunar syndromes and that the influence of the ACE DD genotype may be relevant in mediating the diffuse form of vessel injury.

Polymorphisms of the Factor VII Gene and Circulating FVII:C Levels in Relation to Acute Cerebrovascular Disease and Poststroke Mortality

BACKGROUND AND PURPOSE FVII:C has been shown to be an independent risk factor for myocardial infarction and is related to environmental and genetic factors. This study sought to investigate FVII:C levels and factor VII (FVII) gene polymorphisms in relation to stroke and disease outcome. METHODS To examine the association of FVII:C and the Msp I and promoter insertion polymorphisms of the FVII gene in acute stroke, 317 patients and 198 age-matched control subjects were studied. RESULTS FVII:C levels were significantly lower in patients at onset than 3 months later (119% versus 135%, respectively; P < .0005). Levels were significantly lower in patients at onset than in control subjects (124% [95% confidence interval, 120% to 129%] versus 141% [95% confidence interval, 135% to 148%], respectively; P < .0005) but were not significantly different at 3 months (135% [95% confidence interval, 128% to 141%] versus 141% [95% confidence interval, 135% to 148%], respectively). We found no difference in genotype distribution for either polymorphism between patients and control subjects, no difference in FVII:C level or genotype distribution between pathological types of stroke, and no relationship with poststroke mortality. Both polymorphisms were significantly associated with FVII:C levels in patients and control subjects. In a multiple regression model for patients, Msp I genotype, cholesterol, and smoking remained as independent predictors of FVII:C levels, accounting for 32% of interindividual variation. CONCLUSIONS These results suggest that neither FVII:C levels nor FVII gene polymorphisms are associated with cerebrovascular disease. There were no genotype-specific correlations of environmental factors with FVII:C, but there was evidence of an acute-phase or consumptive fall in FVII:C levels at the time of stroke, whereas levels increased to those similar for healthy age-matched control subjects by 3 months, when the acute phase had presumably subsided.