Free protein S deficiency in acute ischemic stroke. A case-control study

Ischemic Stroke in the Young

The purpose of this article is to address several challenging questions in the management of young patients (those age 60 and under) who present with ischemic stroke. Do genetic thrombophilic states, strongly associated with venous thrombosis, independently cause arterial events in adults? Should cases of patent foramen ovale be closed with mechanical devices in patients with cryptogenic stroke? What are the optimal treatments for cerebral vein thrombosis, carotid artery dissection, and antiphospholipid syndrome and are DOACs acceptable treatment for these indications? What is the mechanism underlying large vessel stroke in patients with COVID-19? This is a narrative review. We searched PubMed and Embase and American College of physicians Journal club database for English language articles since 2000 looking mainly at randomized clinical trials, Meta analyses, Cochran reviews as well as some research articles viewed to be cutting edge regarding anticoagulation and cerebrovascular disease. Searches were done entering cerebral vein thrombosis, carotid dissection, anticoagulation therapy and stroke, antiphospholipid antibody and stroke, stroke in young adults, cryptogenic stroke and anticoagulation, patent foramen ovale and cryptogenic stroke, COVID-19 and stroke.

Rivaroxaban in Recurrent Ischemic Stroke Due to Protein S Deficiency: A Case Report

Protein S deficiency is a thrombophilia associated with an increased risk of thromboembolism. Previous studies have shown its role as a predisposing factor for venous thromboembolism, but its role in recurrent arterial ischemic stroke remains uncertain. Here we report a patient with recurrent ischemic stroke due to protein S deficiency. Oral anticoagulant treatment with vitamin K antagonist (VKA) drugs is used to treat and prevent thromboembolic events caused by thrombophilia, but it has many limitations, especially in the case of recurrent thromboembolic events. Direct oral anticoagulants (DOACs) have many advantages over VKA. Previous studies have shown that they are safe in cases of thrombophilia, but they are not well studied in recurrent ischemic stroke due to protein S deficiency. In this study our patient was treated with rivaroxaban. Protein S deficiency may be a predisposing factor in recurrent ischemic stroke, and rivaroxaban can be a safe and effective treatment option. Further studies are needed to confirm our findings.

Prothrombotic Factors Have Significant Association with Arterial and Venous Strokes in Indian Tamilians

BACKGROUND

Prothrombotic factors have been correlated with vascular events in young patients, with recurrent strokes, and with venous thromboembolisms. However, their prevalence in adult strokes, in healthy populations, and in specific ethnic groups is not well defined. We investigated the association of prothrombotic factors with strokes in a South Indian Tamil population.

METHODS

In this hospital-based cross-sectional study, plasma homocysteine (Hcys), protein C and protein S activity levels, activated protein C resistance (APCR) as a surrogate for factor V Leiden (FVL), fibrinogen, and antithrombin III (ATIII) were determined from 75 consecutive patients with ischemic stroke (IS), 25 with cortical venous thrombosis (CVT), and 75 healthy control participants. The Student t test or Mann-Whitney U test was used for comparing prothrombotic factor levels between the stroke and control groups. The χ2 or Fisher exact test was used for comparisons of proportions of thrombophilia and estimation of odds ratios. Mid-P correction was done for multiple estimations.

RESULTS

Hcys levels in patients with IS were significantly higher compared with those in healthy control participants (P = 0.02). Proportions of ATIII deficiency and hyperfibrinogenemia were significantly higher in the IS group, and no healthy control participants had hyperfibrinogenemia. Protein C deficiency was more frequent in those with IS (17%; P < 8 × 10-5) and CVT (P < 10-7) compared with healthy control participants, and protein C activity levels (P = 0.016) were also significantly lower in patients with CVT. Other parameters had no significant associations with IS and CVT. The frequency of protein S deficiency was high in healthy control participants (60%) and in both patients with IS (45%; P = 0.1) and patients with CVT (48%; P = 0.4). No patients or control participants had abnormal APCR.

CONCLUSIONS

In Tamilian participants, several prothrombotic factors were associated with IS. Protein C deficiency alone was associated with CVT. Replication of the pattern in genetically linked populations around the world may affect management of stroke in those populations.

Utility of current thrombophilia screening in young patients with stroke and TIA

Introduction

Approximately 40% of strokes in young adults are cryptogenic. The diagnostic yield of thrombophilia screening remains controversial. We aimed to determine utility of current thrombophilia testing for young patients with stroke and transient ischaemic attack (TIA).

Methods

We present a retrospective review of all patients with stroke and TIA ≤60 years presenting to University College London Hospital stroke unit and daily TIA clinic from 1 January 2015 to 1 August 2016. Consecutive clinical records and thrombophilia tests, including factor V Leiden (FVL), prothrombin G20210A mutation (PGM), antiphospholipid antibody (APA), and protein S, C and antithrombin (AT) levels, were reviewed.

Results

The mean age of 628 patients with stroke and TIA was 49.1 years (SD 9.2). Thrombophilia testing was performed in 360 (57%) patients, including 171 with stroke and 189 with TIA. Positive tests were found in 50 (14%) patients, of whom 24 patients were <50 years. Positive results were found in 36 (10%) with acute ischaemic stroke, 4 (1%) with haemorrhagic stroke and 10 (3%) with TIA. Thirteen patients (4%) had homozygous/heterozygous FVL or PGM, and 27 (7.5%) had positive APA (anticardiolipin antibody, anti-β2 glycoprotein antibody or lupus anticoagulant). Of 27 (7.5%) patients with protein C, S or AT deficiency, 10 (2.8%) had primary deficiency, presumed hereditary with other secondary causes excluded. 9% of patients with protein C, S or AT and 27% with APA were followed by confirmatory testing.

Conclusion

Thrombophilia testing was positive in only 14% of cases overall. Thrombophilia mutations and protein C, S or AT abnormalities were found rarely and were very uncommon in patients with TIA. Follow-up of abnormal results was generally poor for all groups, which further limited the impact of the thrombophilia testing policy.

Cerebral venous thrombosis in a Caribbean population

INTRODUCTION

Cerebral venous thrombosis (CVT) is a rare affliction characterized by a wide diversity in its clinical expression and etiologies. Data from black populations concerning CVT are limited. We examined the clinical, radiological, and etiological aspects as well as the outcome of CVT in Guadeloupe, a French Overseas Department in the Caribbean.

METHODS

All patients hospitalized between 2000 and 2011 at the University Hospital of Pointe-à-Pitre and diagnosed with CVT were retrospectively studied. Forty-five patients, each having had a medical imaging confirming the diagnostic, were retained.

RESULTS

The frequency of CVT in Guadeloupe was estimated at 15 to 20 per 100,0000 per year in our survey. Our patients were largely composed of young women (73.3%). The average patient age was 40 years (14 to 80), with an incidence peak for women in the 20 to 50 years age range. The onset was sub-acute in 69% of cases, where headaches represented 93% of initial symptoms. Thrombosis of the SLS (60%), and of the lateral sinuses (64.4%) were the most frequently encountered. We observed a majority of mild clinical forms with a good functional prognosis. The main etiological factors were oral estro-progestative contraception (40%), and a positive thrombophilia test (33.3%). The thrombophilia factors in Guadeloupe differed from those in Caucasian populations, with a higher frequency of protein S deficit.

CONCLUSION

The clinical and radiological characters are similar to those described in classical studies. Our study suggests a higher incidence of CVT in Guadeloupe, compared to results from Western countries. Further investigation is necessary to better characterize the thrombo-embolic venous risk factors in the black population. Protein S deficit appears to be the most frequent cause of thrombophilia in our population.

Isolated protein S deficiency presenting as catastrophic systemic arterial and subsequently venous thrombosis

Isolated protein S deficiency is an inherited condition having proven association with venous thromboembolism. There is controversy regarding clear association between protein S deficiency and arterial thrombosis. It is therefore necessary to bring focus to this uncommon clinical condition and highlight the probable association with arterial thrombosis facilitating timely diagnosis of this condition. We describe a 48-year-old male with stroke and pulmonary thromboembolism with chronic deep vein thrombosis secondary to isolated protein S deficiency, managed with thrombolysis and long-term anticoagulation.

Free protein S level as a risk factor for coronary heart disease and stroke in a prospective cohort study of healthy United Kingdom men

Plasma protein S (PS) levels are reportedly low in patients with venous thrombosis but high in coronary heart disease (CHD) patients. The authors examined the association between free PS concentration and CHD or stroke risk and assessed risk in combination with C-reactive protein (CRP) levels. Free PS concentration was determined in 6 annual visits among 3,052 middle-aged (49-64 years) United Kingdom men from the Second Northwick Park Heart Study, with 297 CHD events from 1989 to 2005. The highest (vs. first) quintile was associated with a significantly increased CHD risk after adjustment for all other risk factors and correction for regression dilution bias (hazard ratio = 1.85, 95% confidence interval: 1.08, 3.16; P = 0.024). Models that included all well-known risk factors plus PS quintiles improved prediction of CHD (net reclassification improvement (NRI) = 7.0% (P = 0.007), category-less NRI (>0) = 22.1% (P < 0.001)), and the likelihood ratio statistic increased significantly (P = 0.018). The increase in CHD risk was particularly strong when subjects also had high CRP levels. There was no association between free PS level and stroke risk. This study confirms the independent association of elevated free PS levels with future risk of CHD, although elevated PS levels added only modestly to prediction metrics. The novel finding of increased CHD risk, particularly when CRP and PS levels are high, requires further study.

Protein S deficiency: Recurrent ischemic stroke in young

Stroke in young poses a major health problem. Thrombophilic factors have been implicated in 4-8% of the young strokes worldwide. Protein S deficiency is a rare cause of recurrent ischemic stroke in young population. Only a few sporadic cases have been described in the literature. We are reporting a case of protein S deficiency-related recurrent ischemic stroke in a 16-year-old girl. Early diagnosis and targeted approach can help such patients to prevent recurrent thrombotic episodes.

Role of investigating thrombophilic disorders in young stroke

Our knowledge about various inherited and acquired causes of thrombophilic disorders has increased significantly during the past decade. Technology for various diagnostic tests for these rare disorders has matched the rapid advances in our understanding about the thrombophilic disorders. Inherited thrombophilic disorders predispose young patients for various venous or arterial thrombotic and thromboembolic episodes. Our understanding has also improved about various gene-gene and gene-environment interactions and their impact on the resultant heterogenous clinical manifestations. We describe various thrombophilic disorders, their diagnostic tests, pathogenic potential in isolation or with other concurrent inherited/acquired defects and possible therapeutic and prophylactic strategies. Better understanding, optimal diagnostic and screening protocols are expected to improve the diagnostic yield and help to reduce morbidity, disability, and mortality in relatively younger patients harbouring these inherited and acquired thrombophilic disorders.

Prothrombotic risk factors in the evaluation and management of perinatal stroke

The ischemia in children affected by perinatal stroke has long been thought to be driven by nonhematologic maternal and perinatal events. New information from clinical studies, however, tells us that plasma-phase risk factors, such as factor V Leiden, elevated lipoprotein (a), and mutations in MTHFR, may be important in the pathogenesis of perinatal stroke, if not always in the risk of recurrence. With regard to stroke recurrence, this risk is only about 2% according to the largest follow-up study to date, and certainly less than 5%. Nonetheless, when strokes do recur, they tend to be associated with the presence of plasma-phase risk factors in the affected child, suggesting that a small percentage of children with a first perinatal stroke may benefit from anticoagulation therapy, both to prevent stroke recurrence as well as occurence of a second, non-CNS thrombotic event. Counselling of parents with regard to subsequent pregnancies should always include medical management of systemic maternal disorders, such as diabetes, persistently elevated antiphospholipid antibodies, and inherited maternal hypercoagulability states.

Protein S type III deficiency is no risk factor for venous and arterial thromboembolism in 168 thrombophilic families: a retrospective study

Free protein S rather than total protein S levels are currently measured to detect inherited protein S deficiency. Because type III (free protein S) deficiency is still not established as risk factor for thrombosis, we assessed the absolute risk of venous and arterial thromboembolism in a family cohort study. Annual incidences in first-degree relatives with and without protein S deficiency type III were compared. Probands had experienced thrombosis and had either the prothrombin G20210A mutation, increased factor VIII:C levels or hyperhomocysteinemia. Relatives were tested for these thrombophilic disorders and factor V Leiden. Levels of antithrombin, protein C, total and free protein S, and factor XI:C were additionally measured. Of 500 relatives enrolled, 105 were excluded from analysis because they could not be classified, due to acquired conditions. Protein S deficiency type III was demonstrated in 60/395 remaining relatives (15%). Other thrombophilic defects were equally distributed among deficient and non-deficient relatives. Annual incidences of venous thromboembolism were 0.28 per 100 person-years [95% confidence interval (CI), 0.09-0.66] in deficient relatives versus 0.20 per 100 person-years (95% CI, 0.12-0.30) in non-deficient relatives [hazard ratio, 1.4 (95% CI, 0.4-4.0)]. For arterial thromboembolism these values were 0.16 per 100 person-years (95% CI, 0.03-0.46) versus 0.10 per 100 person-years (95% CI, 0.05-0.19) [hazard ratio, 1.5 (95% CI, 0.3-6.0)]. These results suggest that protein S deficiency type III is not associated with an increased risk of either venous or arterial thromboembolism.

Difference in absolute risk of venous and arterial thrombosis between familial protein S deficiency type I and type III. Results from a family cohort study to assess the clinical impact of a laboratory test-based classification

Hereditary protein S (PS) deficiency type I is an established risk factor for venous thromboembolism. Contradictionary data on type III deficiency suggests a difference in risk between both types. We studied 156 first degree relatives (90% of eligible relatives) from type I deficient probands (cohort 1) and 268 (88%) from type III deficient probands (cohort 2) to determine the absolute risk of venous and arterial thromboembolism. Annual incidences of venous thromboembolism were 1.47 and 0.17 per 100 person-years in deficient and non-deficient relatives in cohort 1 [relative risk (RR) 8.9; 95% confidence interval (CI) 2.6-30.0], and 0.27 vs. 0.24 in cohort 2 (RR 0.9; 95% CI 0.4-2.2). Type III deficiency was demonstrated in 20% of non-deficient relatives in cohort 1 and the annual incidence in this subgroup was 0.70 (RR 4.3;0.95-19.0). The cut-off level of free PS to identify subjects at risk was 30%, the lower limit of its normal range (65%). PS deficiency was not a risk factor for arterial thromboembolism. In conclusion, type I deficiency was found to be a strong risk factor for venous thromboembolism, in contrast with type III deficiency. This was because of lower free PS levels in type I deficient subjects and a free PS cut-off level far below the lower limit of its normal range.

Screening for hypercoagulable syndromes following stroke

Patients with ischemic stroke of unclear etiology are often screened for hypercoagulable syndromes or thrombophilias. These have been recognized to cause venous thrombosis, and include hereditary deficiencies of coagulation factors, genetic mutations, or acquired disorders. However, the majority of coagulation disorders are only rarely associated with ischemic stroke. The tests most commonly used to screen for thrombophilias comprise a complex array of assays that may be unreliable in various settings, including acute thrombosis, inflammation, and uses of medications such as anticoagulants. The diagnostic yield of thrombophilia tests in unselected stroke patients is very low, but may improve with careful selection of younger patients who have an otherwise undetermined cause of stroke or a history of venous thrombosis or multiple miscarriages. Various strategies have been developed that can guide the selection of patients (based on specific characteristics) and tests in the evaluation of thrombophilias. Although the diagnosis of thrombophilia aids in the potential explanation of stroke etiology, the best regimen for secondary prevention treatment for the majority of thrombophilias is still unknown.

The prevalence of protein C, protein S, and antithrombin III deficiency in non-APS/SLE Chinese adults with noncardiac cerebral ischemia

Protein C (PC), protein S (PS), and antithrombin III (AT-III) are vital thrombin antagonists in circulation. However, the prevalence of these natural inhibitors for cerebral ischemia is barely mentioned in the Chinese population. The prevalence of PC, PS, and AT-III deficiency in Chinese adults with cerebral ischemia is reported. The study subjects were free of antiphospholipid antibody syndrome or systemic lupus erythematosus. Cardiac, liver, and renal function were normal. An overall rate of thrombophilia was 27%. PS deficiency was the most common disorder, followed by PC with PS and PC deficiency. There was only one patient with AT-III deficiency. No gender was specific for thrombophilia. However, PS deficiency was predilected in young adults. A positive correlation between PC and AT-III was achieved in patients with a normal PC activity but not PC deficiency. There was no correlation between AT-III or PS. The odds ratios of PC and PS were 5.29 and 2.86, respectively. Accordingly, an inability for thrombin antagonization by the PC/PS axis may relate to the occurrence of cerebral ischemia in the Chinese population. AT-III seems to display a minor role only.

Coagulopathies and arterial stroke

Although hypercoagulable states are most often associated with venous thrombosis, arterial thromboses are reported in protein S, protein C, and antithrombin III deficiencies, factor V Leiden and prothrombin gene mutations, hyperhomocysteinemia, dysfibrinogenemia, plasminogen deficiency, sickle cell disease, and antiphospholipid antibody syndrome.

A review of the technical, diagnostic, and epidemiologic considerations for protein S assays

OBJECTIVES

To review the state of the art relating to protein S deficiency as a risk factor for thrombosis and to make recommendations regarding the use of protein S measurements in the assessment of thrombotic risk in individual patients and families.

DATA SOURCES, EXTRACTION, AND SYNTHESIS

Selection criteria were developed for the inclusion of publications from 1985 to 2001 based on the relevant literature concerned with the systematic review of diagnostic tests. Minimal selection criteria were agreed on and the articles stratified into level 1 if they met these criteria and level 2 if they did not meet these criteria. The included articles were reviewed by the authors and abstracted onto predetermined data collection forms. These forms were then scored and recommendations based on level 1 studies. As described elsewhere, results of discussions at the College of American Pathologists Conference XXXVI on Diagnostic Issues in Thrombophilia were used to revise the manuscript into its final form.

CONCLUSIONS

Consensus was reached on 16 recommendations for the use of protein S assays in the assessment of thrombotic risk in individuals and families. Two themes run through the conclusions. First, protein S assays are the most technically problematic of the assays reviewed at this conference. Second, only 2 papers evaluating the diagnostic use of protein S assays met our level 1 inclusion criteria. These 2 problems point out the need for better standardized assays and rigorous studies of the diagnostic utility of these assays.

Genetic risk factors in young adults with 'cryptogenic' ischemic cerebrovascular disease

Mutations such as factor V Leiden G1691A (FVL), prothrombin G20210A (FIIM), methylenetetrahydrofolate reductase (MTHFR) C677T, cystathionine beta-synthase (CBS) 844ins68 and endothelial cell protein C receptor (EPCR) 4031ins23 are risk factors for thromboembolism. To assess the role of these mutations in young adults with cerebral ischemia of otherwise undetermined etiology, 93 patients younger than 50 years old with thromboembolic strokes or transient ischemic attacks were studied. One hundred and eighty-six healthy age-matched and sex-matched blood donors served as controls. The FVL mutation was detected in 15/93 patients and 13/186 controls. After adjustment for smoking, arterial hypertension, and hyperlipidemia, the association of the FVL mutation with cerebral ischemia [odds ratio (OR), 3.19; 95% confidence interval (CI), 1.38-7.39] remained significant. One of 93 patients and 6/186 controls were carriers of FIIM (OR, 0.33; 95% CI, 0.04-2.75). We detected the MTHFR TT677 genotype in 9/93 patients and 26/186 controls (OR, 0.66; 95% CI, 0.30-1.47), a CBS 844ins68 mutation in 12/93 patients and 19/186 controls (OR, 1.30; 95% CI, 0.60-2.81), and an EPCR 4031ins23 mutation in 1/93 patients and in no control individual (P = 0.33). In conclusion, in younger adults the FVL mutation is a risk factor for cerebrovascular disease. FIIM, the MTHFR TT677 genotype and the CBS 844ins68 mutation did not contribute to the risk in this group of patients. The EPCR 4031ins23 mutation is very rare, its possible role needs further investigation.

Arterial ischemic stroke in childhood: the role of plasma-phase risk factors

The role of plasma-phase risk factors for stroke in the pediatric age group is presently unclear due to the lack of sufficiently large prospective studies, and due to the fact that these risk factors do not apply uniformly to newborns, children with sickle cell disease, and older children. Available evidence indicates that factor V Leiden, prothrombin 20210A, and lipoprotein (a) are all important in the pathogenesis of arterial ischemic stroke in older children, but the role of other plasma-phase risk factors remains uncertain. The contribution of these risk factors to newborn stroke and the stroke of children with sickle cell disease is similarly unclear, likely because the ischemia in affected children is predominantly due to nonhematologic perinatal events and erythrocyte adhesion to endothelium with obstruction of flow in the cerebral microcirculation, respectively. Evaluation of childhood stroke should, in our view, always be performed from the standpoint of the presenting clinical symptoms, diagnostic imaging, and determination of plasma-phase risk factors. Therapeutic anticoagulation and use of antiplatelet agents at present focus on the older child.

Natural anticoagulants (antithrombin III, protein C, and protein S) in patients with mild to moderate ischemic stroke

BACKGROUND AND PURPOSE

The role of the natural anticoagulants, antithrombin III (AT III), protein C (PC), and protein S (PS), in patients with mild to moderate ischemic stroke remains uncertain. We aimed to find out whether their levels in peripheral blood correlated with the severity of neurological deficit or can predict clinical outcome and recurrence.

METHODS

We studied AT III, PC, and free PS levels in 55 consecutive patients likely to survive the study period on admission, 1 week, 1 month and 3 months after a first-ever ischemic stroke. Sex- and age-matched controls were studied once. All patients underwent a full neurological examination and blood sampling at each study time point; comprehensive stroke risk factors were recorded, and the etiology of the ischemic stroke was determined. All patients were contacted 3 years later for possible recurrent ischemic events.

RESULTS

AT III level was found to be significantly lower at all time points after stroke; PC level was significantly increased on admission and normal at subsequent measurements, and PS level was normal on admission but significantly decreased later. The levels of the natural anticoagulants did not correlate with the etiology of stroke, any stroke risk factor, or neurological scores, except that the AT III level on admission showed significant correlation with stroke severity and disability at 3 months. Natural anticoagulant levels did not predict recurrence of ischemic stroke.

CONCLUSIONS

The measurements of the level of AT III, PC, or PS did not deliver useful information for management of patients with mild or moderate ischemic stroke, expect that AT III level on admission might predict outcome.

Stroke in the postoperative period

Stroke in the postoperative period requires a certain level of sophistication in dealing not only with the patient, but also with the family and significant others. The consultant who is called in to assess the patient must deal with the delicate matter of addressing a presumably unforeseen complication; this often requires political deftness when the surgeon is reluctant to acknowledge that anything possibly could go awry. It is the ultimate hope of all involved that the patient will have a speedy and full recovery. It is important for the patient to be evaluated properly and thoroughly in an effort to prevent a minor, reversible deficit from becoming a major, irreversible neurologic disability. Family members should have all findings and the implications of such findings thoroughly explained to them. Efforts to minimize the potential ramifications of a postoperative stroke generally are not well received and can lead to questions about the integrity of the surgical team as well as the quality of care.

An association between plasma free protein s concentration and risk of coronary heart disease in middle-aged men

Protein S is a vitamin K-dependent protein with anticoagulant properties. Case series have reported reduced plasma concentrations in patients with arterial thromboses, while other studies have reported increased levels in patients with coronary heart disease (CHD). The present study sought to clarify the relation between free protein S and risk of CHD. A prospective survey was conducted of 3000 men aged 50 to 61 years, free of clinical CHD at baseline. Free protein S was measured by commercial immunoassay. End-points recorded were sudden coronary death, first nonfatal and fatal myocardial infarction (MI), surgical intervention for symptomatic, angiographically demonstrated CHD, and all-causes mortality. Statistical analysis employed univariate incidence rate ratios followed by Cox proportional hazards regression. There were 168 CHD events recorded during 21,000 person-years of risk. Mean free protein S concentration was 6% higher in those who developed CHD than in the remainder, the crude hazard ratio (HR) for a one standard deviation (S.D.) increase in free protein S being 1.25 (95% CI, 1.08-1.25). Free protein S was associated with cholesterol concentration and other conventional CHD risk factors. In multivariate regression analysis, after adjustment for conventional CHD risk factors a 1 S.D. increase in free protein S was associated with a HR of 1.15 (0.98-1.35) for CHD, of borderline conventional statistical significance. This association of free protein S with risk of CHD may reflect effects of plaque-destabilising inflammatory activity on protein S levels.

Interaction between interleukin-6 and the natural anticoagulant system in acute stroke

Inflammatory reactions mediated by cytokines are involved in the pathogenesis of acute stroke. Decrease in circulating levels of protein C (PC) and protein S (PS) induced by inflammatory cytokines has been postulated as a potential mechanism for a procoagulant tendency during acute stroke. The procoagulant state associated with impairments in natural anticoagulants may induce microvascular obstruction leading to a tissue perfusion reduction that worsens cerebral ischemia. Interleukin-6 (IL-6) regulate the synthesis of C4b-binding protein (C4BP), an acute-phase protein that also regulates PS plasma levels. We measured IL-6, C4BP, erythrocyte sedimentation rate (ESR), total and free PS and PC in 44 patients with acute ischemic stroke to determine if IL-6 decreases circulating levels of natural anticoagulants through the C4BP pathway and if these acute changes in natural anticoagulants may have clinical implications. Patients with higher levels of IL-6 had more severe neurologic deficits on admission, greater infarct size, higher levels of acute-phase reactants, and lower levels of free PS. IL-6 was significantly correlated with C4BP, ESR, and free PS levels. PC levels were also lower in the group of patients with greater IL-6, but differences were not statistically significant. No correlations were found between C4BP and natural anticoagulants. Severe neurologic deficit, greater infarct volume, atrial fibrillation, increased levels of inflammatory parameters (ESR and IL-6), and reduced levels of free PS were associated with disabling stroke at 3 months, but only neurologic severity and ESR remained as independent predictors of stroke disability on multiple regression analysis. Inflammatory reactions mediated by IL-6 during the acute phase of stroke influence the modulation of free PS. However, variations in free PS levels do not have implications for clinical outcome in stroke patients. The link between proinflammatory cytokines and free PS in the acute phase of stroke is not related to the C4BP pathway.

Association between deficiency of free protein S and anticardiolipin antibodies in patients </= 65 years of age with acute ischemic stroke and TIA

A possible association between anticardiolipin antibodies (ACA), which are a marker for increased risk of cerebral ischemia, and deficiency of free Protein S, a naturally occurring anticoagulant, has been suspected in some studies of ischemic stroke, particularly in young adults. In order to investigate this further, we prospectively studied all stroke patients </= 65 years of age admitted to our stroke unit during 1991-1992. A total of 66 patients with acute ischemic stroke or transient ischemic attacks (TIA) (embolic/thrombotic infarction n = 30, embolic infarction n = 13, thrombotic infarction n = 10, and TIA n = 13) were analysed for ACA, protein C and S, free protein S and antithrombin III (AT III). Traditional risk factors were scrutinized in each patient. Eight patients had some previously undetected derangement of the coagulation process; five had elevated ACA levels, four had low, free Protein S levels, and three had low AT III levels. None of the patients showed any decrease in total protein C or S levels. A striking association between the presence of ACA and free protein S deficiency was noted. All patients with free protein S deficiency had concomitant elevated ACA levels. Sixteen patients had had a previous episode of ischemic stroke/TIA or mycocardial infarction, two of them had lowered AT III levels. Thirty-four patients had one or more elevated infectious parameters but with no clear correlation to derangement of the coagulation factors. We conclude that a probable association between ACA and free protein S deficiency exist in ischemic stroke patients, and that it may have a pathogenetic importance. Copyright 1998 Lippincott Williams & Wilkins

Antithrombin, protein C and protein S levels in 127 consecutive young adults with ischemic stroke

OBJECTIVES

The aim of our study was to evaluate the prevalence of antithrombin, protein C and protein S deficiencies in consecutive ischemic stroke patients under 45.

MATERIAL AND METHODS

We studied 127 consecutive patients with a mean age of 34.4 years admitted for an ischemic stroke, over a 2-year period, after exclusion of those with arterial dissection. Antithrombin, protein C and protein S levels were measured in all patients at the acute stage of the ischemic stroke and measurements were repeated in case of abnormality.

RESULTS

We found abnormal levels in 9 patients. Seven had an acquired cause of deficiency (pregnancy, oestrogen, acute inflammation). Two had no obvious acquired cause of deficiency but further controls were normal.

CONCLUSIONS

Hereditary deficiencies of coagulation inhibitors are rare in ischemic stroke patients under 45 and their systematic detection seems to be of poor interest.

Protein C and S deficiency in children with ischemic cerebrovascular accident

A prothrombotic state caused by a deficiency of protein C or protein S, each an inhibitor of coagulation cascade, increases the risk of ischemic cerebrovascular accident (ICVA) in young adults. This retrospective review studies the relationship of protein C or S deficiency with childhood ICVA. From 1989 to 1995, 37 children were diagnosed by neuroimaging with ICVA unrelated to any known preexisting diagnosis. Protein C deficiency or protein S deficiency was the only identified risk factor for 5.4% (2 patients) and 13.5% (5 patients), respectively, of these 37 children. The data suggest that protein C or protein S deficiency is an important risk factor of ICVA in children.

[Cerebral infarctions in young patients related to deficiency of natural anticoagulants. Protein C and protein S]

The possible etiologies of cerebral infarcts (CI) in young patients differ from those in the older stroke population. Recently, deficiencies of fibrinolytic factors emerged as an important etiology of stroke in the young population. The literature has emphasized the diagnosis of such conditions especially in stroke cases of undetermined etiology and with history of recurrent thrombosis. We carried out a research on the serum level of protein C, protein S, and antithrombin III in young patients, between 15 and 40 years, with CI of undetermined cause after application of a standard protocol. Three patients had low levels of these proteins; two had protein C deficiency, and one protein S deficiency. None of them had antithrombin III deficiency. We conclude that systematic investigation of such causes of cerebral infarct will reduce the group of undetermined strokes, and will open the possibility of prophylactic treatment in a non-negligible group of patients.

Hematologic disorders associated with ischemic stroke

Hematological disorders underlie a small proportion of all ischemic strokes. The association of these coagulation abnormalities with ischemic stroke is not always clear. The etiology of stroke still remains uncertain in a large number of cases and proper screening for coagulation abnormalities and the discovery of new coagulation disorders will probably increase the rate of strokes attributable to these causes. Since large case-control studies with unselected and consecutive stroke patients from different ethnic origins have not yet been performed to determine the role of coagulation abnormalities in ischemic stroke, our knowledge is dependent on case reports and small series of mostly younger patients. Extensive hematologic evaluation of unselected stroke patients will likely yield little useful information and be too expensive. Every stroke patients needs a careful evaluation, and in selected cases, this should include coagulation parameters. Patients with unexplained strokes after a careful evaluation, previous thrombotic episodes, or a positive family history for thrombosis, are good candidates for further coagulation studies. As long as the hypercoagulable state persists, both arterial and venous thromboembolic recurrences can be expected. Many of these patients may benefit from anticoagulants. In patients with hereditary coagulation disorders, studies should be extended to close relatives. Since some coagulation tests are fairly expensive, provide only equivocal data, and are not widely available, we advise a step-by-step approach starting with the patient and family history.

Cerebral ischemia in a patient with protein S deficiency and carotid stenosis

Congenital protein S deficiency is an important risk factor for venous and, more rarely, arterial thrombosis. Here, we describe the case of a 35-year old patient with cerebral ischemia, protein S deficiency and carotid stenosis. Other members of the family were found to have the same protein S deficit and a history of venous thrombotic manifestations.