Acute phase response in cerebral infarction

Which one predicts mortality better in acute ischemic stroke: negative vs positive acute-phase reactants

AIM

The aim of the study is to investigate the relationship between negative acute-phase reactants and positive acute-phase reactants with in-hospital mortality in patients diagnosed with acute ischemic stroke (AIS) in the emergency department (ED).

METHODS AND MATERIALS

Patients aged 18 and older who presented to the ED of a tertiary hospital with AIS were included in the study. Demographic and clinical characteristics, laboratory parameters, acute-phase reactants, National Institutes of Health Stroke Scale (NIHSS), and outcome data of the included patients were recorded on a standard data form.

RESULTS

A total of 588 patients were included in the study. When the in-hospital mortality of patients was examined, the mortality rate was 17.7%. In the analysis for predicting mortality, it was determined that albumin had the highest predictive power between the area under the curve (AUC) and the determined predictive values (AUC: 0.759, 95% CI 0.707-0.810, p < 0.001). The analyses of the study data revealed that albumin (<0.001) and TF (p = 0.049), which are negative acute-phase reactants, were independent predictors of mortality. According to our study data, in patients with AIS, for each unit decrease in albumin level at the time of ED admission, the risk of mortality increased by 0.868 times, and for each unit decrease in TF level, the risk of mortality increased by 0.593 times.

CONCLUSION

According to the study data, albumin and TF levels, which are negative acute-phase reactants, are independent determinants of in-hospital mortality in patients with acute ischemic stroke in the emergency department.

Personalised Approach to Diagnosing and Managing Ischemic Stroke with a Plasma-Soluble Urokinase-Type Plasminogen Activator Receptor

Background: The increasing incidence of ischemic stroke has led to the search for a novel biomarker to predict the course of disease and the risk of mortality. Recently, the role of the soluble urokinase plasminogen activator receptor (suPAR) as a biomarker and indicator of immune system activation has been widely examined. Therefore, the aim of the current study was to assess the dynamics of changes in serum levels of suPAR in ischemic stroke and to evaluate the prognostic value of suPAR in determining mortality risk. Methods: Eighty patients from the Department of Neurology, diagnosed with ischemic stroke, were enrolled in the study. Residual blood was obtained from all the patients on the first, third and seventh days after their ischemic stroke and the concentrations of suPAR and C-reactive protein (CRP), as well as the number of leukocytes and National Institute of Health’s Stroke Scale (NIHSS) scores, were evaluated. Results: On the first day of ischemic stroke, the average suPAR concentration was 6.55 ng/mL; on the third day, it was 8.29 ng/mL; on the seventh day, it was 9.16 ng/mL. The average CRP concentration on the first day of ischemic stroke was 4.96 mg/L; on the third day, it was 11.76 mg/L; on the seventh day, it was 17.17 mg/L. The number of leukocytes on the first day of ischemic stroke was 7.32 × 103/mm3; on the third day, it was 9.27 × 103/mm3; on the seventh day, it was 10.41 × 103/mm3. Neurological condition, which was assessed via the NIHSS, on the first day of ischemic stroke, was scored at 10.71 points; on the third day, it was scored at 12.34 points; on the seventh day, it was scored at 13.75 points. An increase in the values of all the evaluated parameters on the first, third and seventh days of hospitalisation was observed. The patients with hypertension, ischemic heart disease and type 2 diabetes showed higher suPAR and CRP concentrations at the baseline as well as on subsequent days of hospitalisation. The greatest sensitivity and specificity were characterised by suPAR-3, where a value above 10.5 ng/mL resulted in a significant increase in mortality risk. Moreover, an NIHSS-1 score above 12 points and a CRP-3 concentration above 15.6 mg/L significantly increased the risk of death in the course of the disease. Conclusions: The plasma suPAR concentration after ischemic stroke is strongly related to the patient’s clinical status, with a higher concentration on the first and third days of stroke resulting in a poorer prognosis at a later stage of treatment. Therefore, assessing the concentration of this parameter has important prognostic value.

SAA (Serum Amyloid A): A Novel Predictor of Stroke-Associated Infections

BACKGROUND AND PURPOSE

The aim of this study was to evaluate and independently validate SAA (serum amyloid A)-a recently discovered blood biomarker-to predict poststroke infections.

METHODS

The derivation cohort (A) was composed of 283 acute ischemic stroke patients and the independent validation cohort (B), of 367 patients. The primary outcome measure was any stroke-associated infection, defined by the criteria of the US Centers for Disease Control and Prevention, occurring during hospitalization. To determine the association of SAA levels on admission with the development of infections, logistic regression models were calculated. The discriminatory ability of SAA was assessed, by calculating the area under the receiver operating characteristic curve.

RESULTS

After adjusting for all predictors that were significantly associated with any infection in the univariate analysis, SAA remained an independent predictor in study A (adjusted odds ratio, 1.44 [95% CI, 1.16-1.79]; P=0.001) and in study B (adjusted odds ratio, 1.52 [1.05-2.22]; P=0.028). Adding SAA to the best regression model without the biomarker, the discriminatory accuracy improved from 0.76 (0.69-0.83) to 0.79 (0.72-0.86; P<0.001; likelihood ratio test) in study A. These results were externally validated in study B with an improvement in the area under the receiver operating characteristic curve, from 0.75 (0.70-0.81) to 0.76 (0.71-0.82; P<0.038).

CONCLUSIONS

Among patients with ischemic stroke, blood SAA measured on admission is a novel independent predictor of infection after stroke. SAA improved the discrimination between patients who developed an infection compared with those who did not in both derivation and validation cohorts. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00390962.

Serum Amyloid A1 as a Potential Intracranial and Extracranial Clinical Severity Biomarker in Traumatic Brain Injury

Extracranial injury is frequently present in patients with traumatic brain injury (TBI). However, no reliable biomarker exists nowadays to evaluate the magnitude and extension of extracranial injury as well as the identification of patients who are at risk of developing secondary injuries. The purpose of this study was to identify new possible peptide biomarkers by mass spectrometry analysis in patients with TBI and ascertain whether the novel biomarker discovered by peptide mass fingerprinting, serum amyloid A1 (SAA1), is capable of reflecting the condition of the patient and both intracranial and extracranial injury extension. Demographic characteristics, clinical data, and serum samples were prospectively collected from 120 patients with TBI (Glasgow Coma Scale [GCS] score 3-15) on admission. Biomarkers were quantified by enzyme-linked immunosorbent assay. Intracranial lesion volume was measured from the semiautomatic segmentation of hematoma on computed tomography (CT) using Analyze software. Functional outcome was evaluated using the Glasgow Outcome Scale (GOS) at hospital discharge and GOS extended scores at 6 months. The SAA1 levels were significantly associated with intracranial (GCS score at admission, lesion load measured with cranial CT, and pupil responsiveness) and extracranial clinical severity (all Abbreviated Injury Scale regions, Injury Severity Score, major extracranial injury, polytrauma, and orthopedic fractures presence), along with systemic secondary insults and functional outcome. SAA1 was is associated with the volume of traumatic intracranial lesions. The SAA1 levels were correlated with astroglial S100β and glial fibrillary acidic protein (GFAP), neuronal neuron-specific enolase (NSE), and axonal total tau (T-tau) and phosphorylated neurofilament heavy chain (pNF-H) injury markers. SAA1 predicts unfavorable outcome and mortality at hospital discharge (area under the curve [AUC] = 0.90, 0.82) and 6 months (AUC = 0.89). SAA1 can be established as a marker for the overall patient condition due to its involvement in the neuroendocrine axis of the systemic response to craniocerebral trauma.

Proteomic discovery and verification of serum amyloid A as a predictor marker of patients at risk of post-stroke infection: a pilot study

Background

Post-stroke infections occur in 20–36% of stroke patients and are associated with high morbidity and mortality rates. Early identification of patients at risk of developing an infection could improve care via an earlier treatment leading to a better outcome. We used proteomic tools in order to discover biomarkers able to stratify patients at risk of post-stroke infection.

Methods

The post hoc analysis of a prospective cohort study including 40 ischemic stroke patients included 21 infected and 19 non-infected participants. A quantitative, isobaric labeling, proteomic strategy was applied to the plasma samples of 5 infected and 5 non-infected patients in order to highlight any significantly modulated proteins. A parallel reaction monitoring (PRM) assay was applied to 20 additional patients (10 infected and 10 non-infected) to verify discovery results. The most promising protein was pre-validated using an ELISA immunoassay on 40 patients and at different time points after stroke onset.

Results

Tandem mass analysis identified 266 proteins, of which only serum amyloid A (SAA1/2) was significantly (p = 0.007) regulated between the two groups of patients. This acute-phase protein appeared to be 2.2 times more abundant in infected patients than in non-infected ones. These results were verified and validated using PRM and ELISA immunoassays, which showed that infected patients had significantly higher concentrations of SAA1/2 than non-infected patients at hospital admission, but also at 1, 3, and 5 days after admission.

Conclusions

The present study demonstrated that SAA1/2 is a promising predictor, at hospital admission, of stroke patients at risk of developing an infection. Further large, multicenter validation studies are needed to confirm these results. If confirmed, SAA1/2 concentrations could be used to identify the patients most at risk of post-stroke infections and therefore implement treatments more rapidly, thus reducing mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-017-9162-0) contains supplementary material, which is available to authorized users.

Protein-energy malnutrition increases activation of the transcription factor, nuclear factor kappaB, in the gerbil hippocampus following global ischemia

Protein-energy malnutrition (PEM) exacerbates functional impairment caused by brain ischemia. This is correlated with reactive gliosis, which suggests an increased inflammatory response. The objective of the current study was to investigate if PEM increases hippocampal activation of nuclear factor kappaB (NFkappaB), a transcription factor that amplifies the inflammatory response involved in ischemic brain injury. Mongolian gerbils (11-12 weeks old) were randomly assigned to control diet (12.5% protein) or protein-deficient diet (2%) for 4 weeks. The 2% protein group had a 15% decrease in voluntary food intake (P<.001; unpaired t test), resulting in PEM. Body weight after 4 weeks was 20% lower in the PEM group (P<.001). Gerbils were then exposed to sham surgery or global ischemia induced by 5-min bilateral common carotid artery occlusion. PEM independently increased hippocampal NFkappaB activation detected by electrophoretic mobility shift assay at 6 h after surgery (P=.014; 2-factor ANOVA). Ischemia did not significantly affect NFkappaB activation nor was there interaction between diet and ischemia. Serum glucose and cortisol concentrations at 6 h postischemia were unaltered by diet or ischemia. A second experiment using gerbils of the same age and feeding paradigm demonstrated that PEM also increases hippocampal NFkappaB activation in the absence of surgery. These findings suggest that PEM, which exists in 16% of elderly patients at admission for stroke, may worsen outcome by increasing activation of NFkappaB. Since PEM increased NFkappaB activation independent of ischemia or surgery, the data also have implications for the inflammatory response of the many individuals affected globally by PEM.

Inflammatory response after influenza vaccination in men with and without carotid artery disease

OBJECTIVE

Inflammatory markers are associated with vascular disease; however, variation in the acute phase response (APR) has not been evaluated. We evaluated whether the APR magnitude in men with severe carotid artery disease (CAAD) (>80% stenosis) differed from that of men without stenosis (<15% stenosis).

METHODS AND RESULTS

White males with (n=43) and without (n=61) severe CAAD receiving clinical influenza vaccinations were recruited. Their baseline and 24-hour after -vaccination blood samples were assayed for C-reactive protein (CRP), IL-6, and serum amyloid-a (SAA). In vivo APR to vaccination was measurable and varied among subjects. Adjusted for age, smoking, oral hypoglycemics, aspirin, and stain use, the relative 24-hour changes in levels of ln(CRP), ln(IL-6), and ln(SAA) were higher in men with CAAD than in men without, but only the SAA response was significant (P=0.02); the relative SAA response was 1.6 (95% confidence interval, 1.1 to 2.5) times higher in men with than without CAAD. The APR for all markers appeared to be independent of baseline levels.

CONCLUSIONS

Influenza vaccination results in a mild, but measurable, APR in men with and without CAAD. SAA APR variability may be a predictor of severe vascular disease that is independent of basal SAA level.

Are the angiotensin-converting enzyme gene and activity risk factors for stroke?

Stroke is a multifactorial disease in which genetic factors play an important role. This study was carried out to determine angiotensin-converting enzyme (ACE) gene polymorphism in Turkish acute stroke patients and to establish whether there is an association of angiotensin-converting enzyme gene I/D polymorphism with clinical parameters. In this study 185 patients and 50 controls were recruited. We have investigated the association among the allelic distribution of the insertion/deletion (I/D) polymorphism of the ACE gene identified by polymerase chain reaction. Distribution of ACE gene I/D genotypes and allele frequencies in patients were not significantly different from controls. D allele frequencies were 57.8% in patients versus 53.0% in controls and I allele 42.2% versus 47% respectively. History of hypertension, stroke, renal, heart and vessel diseases incidence and age, gender, systolic-diastolic blood pressures and creatinine levels were significantly high in patients. But these results and ACE activities had no significant differences among the ACE genotypes in patients and controls. Our results suggest that the ACE gene polymorphism is not associated with the pathogenesis of stroke in Turkish stroke patients.

Inflammatory response after acute ischemic stroke

BACKGROUND AND PURPOSE

This study aimed to characterize the time course of inflammatory parameters after acute ischemic stroke.

METHODS

We serially determined high sensitivity C-reactive protein (CRP), fibrinogen, and leukocyte counts at 10 time points between days 1 and 90 after ischemic stroke and in control subjects.

RESULTS

CRP did not significantly change, whereas fibrinogen increased after stroke. At all time points, CRP and fibrinogen were higher than in healthy control subjects, but not risk factor control subjects. The leukocyte count declined after stroke and was significantly elevated as compared to both control groups only on day 1 but not later. NIHSS levels were positively correlated with CRP and fibrinogen at all time points. Larger infarcts were associated with a higher CRP and leukocyte counts on day 90. Treatment with aspirin was associated with lower values for all three inflammatory parameters in the subacute phase after ischemia.

CONCLUSIONS

The course after stroke was different between the parameters of inflammation. Only the leukocytes followed the paradigm of an acute phase response.

Risk factors for intracardiac thrombus in patients with recent ischaemic cerebrovascular events

BACKGROUND

Intracardiac thrombus is a common cause of cardiogenic cerebral ischaemia. Stroke recurrence is high, but thrombus detection with therapeutic intervention can reduce the risk. Accurate detection requires transoesophageal echocardiography (TOE), which is semi-invasive and costly.

OBJECTIVE

To identify risk factors for cardiac thrombus, enabling selection of patients for TOE and initiation of measures to prevent the formation of cardiac thrombus.

METHODS

151 consecutive patients with ischaemic stroke or transient ischaemic attacks (mean age 62 years) underwent TOE for intracardiac thrombus detection within one week of a qualifying event.

RESULTS

Intracardiac thrombus was found in 26% of the patients (70% in the left atrial appendage). Multivariate analysis indicated the following clinical correlates: large stroke, odds ratio (OR) = 2.8 (95% confidence interval, 1.2 to 6.4); symptomatic coronary artery disease, OR = 3.0 (1.2 to 7.4); and ECG evidence of ischaemia, OR = 2.8 (1.1 to 7.7). Neither carotid stenosis >70%, nor stroke location correlated with the presence of thrombus.

CONCLUSIONS

Clinical factors correlate with and appear to be risk factors for cardiac thrombus in patients with recent cerebral ischaemia. These may be used to select appropriate patients for invasive and costly TOE investigation, irrespective of the presence of significant carotid stenosis (>/=70%) or stroke location.

Measuring longitudinally the metabolic demands of stroke patients: resting energy expenditure is not elevated

BACKGROUND AND PURPOSE

Little is known of the acute, subacute, and longer-term energy demands of stroke, information essential to appropriate clinical and nutritional management. The goals of this study were to (1) determine the resting energy expenditure (REE) of stroke patients from stroke onset to 3 months, (2) examine relations between stroke size, type, location, severity, and REE, and (3) evaluate whether estimation of REE from the Harris-Benedict equation (HB) requires the addition of a "stress factor" to capture the possible additional REE imposed by stroke.

METHODS

The REE of new stroke patients was measured prospectively at hospital admission and on days 7, 11, 14, 21, and 90 by indirect calorimetry. Stroke patients' REEs (Kcal/d) over time and REEs as a percentage of HB were compared with control subjects' single measurements.

RESULTS

Mean REE and %HB of stroke patients ranged from 1521+/-290 to 1663+/-268 Kcal/d and from 107+/-14.9 to 114+/-12.9 %HB, respectively. Mean measurements of control subjects were 1665+/-265 Kcal/d and 112.9+/-11.4 %HB (NS). REE was not associated with stroke characteristics (NS). Changes in REE measured longitudinally were not clinically meaningful (4 to 62 Kcal/d) though statistically significant (P=0.004).

CONCLUSIONS

The REEs of stroke patients and controls were both approximately 10% higher than those predicted by HB. No hypermetabolic response pattern of energy expenditure was evident after stroke. REE did not vary with stroke characteristics, although confirmation with larger subgroups is required.

Inflammation and infection in clinical stroke

Stroke has enormous clinical, social, and economic implications, and demands a significant effort from both basic and clinical science in the search for successful therapies. Atherosclerosis, the pathologic process underlying most coronary artery disease and the majority of ischemic stroke in humans, is an inflammatory process. Complex interactions occur between the classic risk factors for atherosclerosis and its clinical consequences. These interactions appear to involve inflammatory mechanisms both in the periphery and in the CNS. Central nervous system inflammation is important in the pathophysiologic processes occurring after the onset of cerebral ischemia in ischemic stroke, subarachnoid hemorrhage, and head injury. In addition, inflammation in the CNS or in the periphery may be a risk factor for the initial development of cerebral ischemia. Peripheral infection and inflammatory processes are likely to be important in this respect. Thus, it appears that inflammation may be important both before, in predisposing to a stroke, and afterwards, where it is important in the mechanisms of cerebral injury and repair. Inflammation is mediated by both molecular components, including cytokines, and cellular components, such as leukocytes and microglia, many of which possess pro- and/or antiinflammatory properties, with harmful or beneficial effects. Classic acute-phase reactants and body temperature are also modified in stroke, and may be useful in the prediction of events, outcome, and as therapeutic targets. New imaging techniques are important clinically because they facilitate dynamic evaluation of tissue damage in relation to outcome. Inflammatory conditions such as giant cell arteritis and systemic lupus erythematosus predispose to stroke, as do a range of acute and chronic infections, principally respiratory. Diverse mechanisms have been proposed to account for inflammation and infection-associated stroke, ranging from classic risk factors to disturbances of the immune and coagulation systems. Considerable opportunities therefore exist for the development of novel therapies. It seems likely that drugs currently used in the treatment of stroke, such as aspirin, statins, and modulators of the renin-angiotensin-aldosterone system, act at least partly via antiinflammatory mechanisms. Newer approaches have included antimicrobial and antileukocyte strategies. One of the most promising avenues may be the use of cytokine antagonism, for example, interleukin-1 receptor antagonist.

Cytokine-induced inflammation and long-term stroke functional outcome

Inflammatory reactions are involved in the pathogenesis of cerebral ischemia. Cytokines exacerbate brain ischemic injury by several mechanisms and they activate the synthesis of acute-phase reactants. We evaluated the association between cytokine-induced inflammation and functional outcome in 41 patients with acute ischemic stroke. Blood samples for interleukin-1 receptor antagonist (IL-1ra), erythrocyte sedimentation rate (ESR), c-reactive protein (CRP) and polymorphonuclear leukocyte (PMNL) count were taken within 48 h from stroke onset. Functional outcome was assessed at six months with the Modified Rankin Scale. Patients with a Rankin score > or = 3 were classified as dependent outcome. The effect of inflammatory variables on outcome was analyzed by logistic regression. Mathew score <75 on admission, atrial fibrillation, non-lacunar infarct size, ESR>13 mm/h in men or >20 mm/h in women, PMNL count >8 x 10(9)/l, CRP>0.8 mg/dl and IL-1ra>500 pg/ml were associated with dependent outcome. On multiple logistic regression, severe stroke on admission, non-lacunar infarct size and ESR remain in the predictive model of outcome with a sensitivity and specificity of 76 and 80%, respectively. This study suggests that in addition to clinical evaluation and neuroimaging, measurement of ESR may be useful for the early detection of stroke patients with poor long-term functional outcome.

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 stroke presentation and possession of the D allele may be associated with increased risk of early death from acute cerebral infarction.

Interleukin-6 and interleukin-1 receptor antagonist in acute stroke

Elevated plasma levels of interleukin-6 (IL-6), a key regulator of the acute phase response that includes increased fibrinogen synthesis, have recently been detected in patients with acute stroke. Nevertheless, the role of the acute phase response in stroke has been controversial, with some studies suggesting that preexisting infection accounts for most of the acute phase response. Increased IL-6 could signal the involvement of antiinflammatory activity, since IL-6 stimulates the production of endogenous antiinflammatory mediators such as interleukin-1 receptor antagonist (IL-1RA). To better understand the interaction of pro- and antiinflammatory acute phase processes in brain infarction, plasma levels of IL-1RA, IL-6, and acute phase proteins including fibrinogen and c-reactive protein (CRP) were measured within 4 +/- 2 days of onset in 50 patients with acute ischemic stroke and in 20 age-matched healthy controls. After excluding patients with evidence of infection, both IL-1RA and IL-6 were significantly elevated in stoke patients compared with controls (p < 0.0001). IL-1RA and IL-6 were both significantly correlated with levels of CRP, p < 0.05 and p < 0.001, respectively, but not with each other. Levels of IL-6 and IL-1RA, together with fibrinogen and CRP were higher in patients with infarcts of greater than 3 cm and lowest in patients with lacunar syndromes.(ABSTRACT TRUNCATED AT 250 WORDS)

Early prediction of stroke severity. Role of the erythrocyte sedimentation rate

BACKGROUND AND PURPOSE

Early predictors of functional outcome after stroke are necessary for better planning of treatment and care.

METHODS

We evaluated prospectively early clinical predictors of short-term functional outcome in a group of patients with ischemic cerebral infarction and explored whether the intensity of the acute-phase response provided further information concerning the short-term functional outcome. We evaluated a group of 208 ischemic stroke patients using the Mathew scale at entry. All patients had neuroimaging studies and routine blood tests, including erythrocyte sedimentation rate (ESR), within 72 hours from clinical onset. At discharge, functional outcome was graded according to a Stroke Outcome Scale.

RESULTS

Larger infarcts, more embolic infarcts, and fewer lacunar infarcts were observed in the poor-outcome group. Vascular risk factors, radiological findings not related to the index stroke, time to admission, and treatment were similar in the two outcome groups. Variables with statistically significant differences between outcome groups included the following: age > 65 years, female sex, admission Mathew score < 75, worsening at clinical presentation, infarct volume > 6 cm3, complicating infections, fasting glucose > 110 mg, nonfasting glucose > 130 mg, and elevated ESR. With stepwise logistic regression analysis, Mathew score on admission, infarct volume, mode of clinical presentation, and ESR remained in the predictive model of stroke outcome, with a sensitivity and specificity of 89.91% and 85.71%, respectively. After removing the computed tomographic information from the model the same variables remained, with a sensitivity and specificity of 83.05% and 94.29%, respectively.

CONCLUSIONS

Infarct size and clinical severity on admission are the stronger predictors of short-term functional outcome. Mode of clinical presentation, clinical evolution during the first day of stroke, and ESR are also independent predictors of short-term stroke outcome. These findings might be indicative of an inadequate collateral profile and/or a more pronounced prothrombotic state.

Fibrinogen and the albumin-globulin ratio in recurrent stroke

BACKGROUND AND PURPOSE

In following patients initially recruited for a cross-sectional study of blood viscosity in ischemic cerebrovascular disease, it was noted that those having a low albumin-globulin ratio appeared to experience the majority of subsequent vascular events. Accordingly, a prospective study in which subjects were assigned to a high or low albumin-globulin cohort was undertaken to examine the relation between a low albumin-globulin ratio, the presence of clinical risk factors for stroke, and the occurrence of subsequent stroke, myocardial infarction, or vascular death.

METHODS

Three groups of subjects were followed for an average of 1.5 +/- 0.8 years to ascertain vascular end points. Group 1 consisted of 126 patients with acute ischemic stroke; group 2 included 109 subjects matched with group 1 for age, medications, and recognized clinical risk factors for stroke; and group 3 was composed of 84 healthy volunteers, matched for age with groups 1 and 2. The median albumin-globulin ratio for group 1 at enrollment, 1.45, was used to dichotomize patients into two cohorts: all subjects with an albumin-globulin ratio of 1.45 or less were assigned to the "low" albumin-globulin cohort; those whose ratio was greater than 1.45 were assigned to the "high" albumin-globulin cohort. The occurrence of vascular end points was verified during subsequent hospitalizations and outpatient clinic visits and by telephone interviews of patients and providers.

RESULTS

A total of 51 vascular events occurred, including 39 in group 1, 8 in group 2, and 4 in group 3. Subjects in either group 1 or 2 who were in the low albumin-globulin cohort had at least double the risk for a subsequent vascular event compared with their counterparts in the high albumin-globulin cohort (P < .01 and P < .03, respectively). In comparison with the high albumin-globulin cohort, significantly more patients in the low albumin-globulin cohort in group 1 had a history of prior stroke (P < .03). When groups 1 and 2 were combined, both a low albumin-globulin ratio and diabetes had a significant independent association with increased risk for subsequent vascular events in a Cox proportional-hazards model (P < .01 and P < .03, respectively).

CONCLUSIONS

The results of this study indicate that significantly increased risk for subsequent vascular events in stroke patients and in subjects with clinical risk factors for stroke is associated with a shift in the concentrations of blood proteins to a prothrombotic environment characterized by lower levels of albumin and an increased concentration of globulins and fibrinogen.

Chronic blood hyperviscosity in subjects with acute stroke, transient ischemic attack, and risk factors for stroke

The origin and significance of blood hyperviscosity in subjects with acute stroke has been controversial. It has been argued that viscous abnormalities simply reflect either elevated hematocrit or an acute-phase response to the stroke itself. To address these issues, we measured the factors that determine blood viscosity in a cross-sectional study of 430 subjects, including 135 with acute stroke, 89 with acute transient ischemic attacks of the brain, 115 with recognized risk factors for stroke, and 91 healthy controls. The at-risk group was balanced with the acute stroke group for types of risk factors and medication usage, and all four groups were balanced for age. The viscosity of whole blood at low rates of shear and the plasma viscosity were significantly elevated in both groups with cerebrovascular symptoms and in the at-risk group compared with the healthy controls. The severity of hyperviscosity was stroke group greater than transient ischemic attack group greater than at-risk group greater than healthy controls. Increased viscosity of whole blood was associated with an elevated plasma fibrinogen concentration and with a decreased albumin/globulin ratio. This study provides evidence that blood hyperviscosity is present not only in subjects with acute brain infarction, but also in those with risk factors for stroke, and that these abnormalities are, to a considerable degree, chronic.