Hypercoagulation Testing in Ischemic Stroke

Current status and value of testing antiphospholipid antibody in patients with acute ischemic stroke: a retrospective single-center study in China

BACKGROUND AND PURPOSE

Testing for antiphospholipid antibodies (aPL) is useful to determine the cause of ischemic stroke in young and female patients. However, the clinical relevance of aPL in older patients with ischemic stroke remains unclear. We aimed to explore the status and diagnostic value of initial aPL testing in all patients with acute ischemic stroke.

METHODS

We retrospectively analyzed patients with acute ischemic stroke who were consecutively hospitalized in our hospital between June 2012 and January 2022 and investigated the factors associated with performing aPL screening in real-world clinical practice. Furthermore, factors associated with initial aPL positivity were evaluated by comparing the demographic, etiological, and therapeutic characteristics.

RESULTS

Of 1209 patients, 287 (23.7%) were tested for aPL and 58 (20.2%) tested positive. Physicians tended to conduct aPL testing on female patients (P<0.001), younger patients (P<0.001), patients with fewer vascular risk factors (P<0.001), and multiple infarctions in the multivascular blood supply area (P<0.001). Multivariate logistic regression analysis showed that only stroke of other determined etiology type was a significant influencing factor for positive aPL results (OR 2.97, 95% CI 1.137, 7.774, P=0.026), adjusting for sex, age, and causes of stroke, etc. CONCLUSION: Approximately one-quarter of the patients with acute ischemic stroke were tested for aPL. Age, sex, number of vascular risk factors, and neuroimaging features affected the discretion in performing aPL testing. aPL testing may be appropriate in older patients with no identified cause of ischemic stroke and may provide additional diagnostic opportunities for acute ischemic stroke.

Ph- myeloproliferative neoplasms and the related risk factors for stroke occurrence: Results from a registry of patients treated with Anagrelide

Arterial thrombosis is a common complication in patients with Ph^- myeloproliferative neoplasms (MPN). We searched for the risk factors of stroke in MPN patients from anagrelide registry. We analyzed the potential risk factors triggering a stroke/TIA event in 249 MPN patients with previous stroke (n = 168) or Transient Ischemic Attack (TIA) (n = 140), and in 1,193 MPN control subjects (without clinical history of thrombosis). These patients were registered in a prospective manner, providing a follow-up period after Anagrelide treatment. The median age of the patients in the experimental group was of 56 years of age (ranging from 34-76) and of 53 years of age (ranging from 26-74) in the control group (p < 0.001). Using a multivariate model, we determined the following as risk factors: JAK2V617F mutation (OR 2.106, 1.458-3.043, p = 0.006), age (OR 1.017/year, 1.005-1,029, p = 0.006), male gender (OR 1.419, 1.057-1.903, p = 0.020), MPN diagnosis (OR for PMF 0.649, 0.446-0.944, p = 0.024), BMI (OR 0.687 for BMI > 25, 0.473-0.999, p = 0.05) and high TAG levels (OR 1.734, 1.162-2.586, p = 0.008), all of which were statistically significant for CMP development. Concerning the risk factors for thrombophilia, only the antiphospholipid syndrome (OR 1.994, 1.017-3.91, p = 0.048) was noteworthy in a stroke-relevant context. There was no significant difference between the blood count of the patients prior to a stroke event and the control group, both of which were under a cytoreductive treatment. We found that age, male gender, JAK2V617F mutation, previous venous thrombosis, and hypertriglyceridemia represent independent risk factors for the occurrence of a stroke in Ph^- MPN patients.

No Association between Ischemic Stroke and Portal Vein Thrombosis in Liver Cirrhosis

BACKGROUND AND AIMS

There seems to be a higher risk of ischemic stroke and portal vein thrombosis in liver cirrhosis. Both of them may be associated with hypercoagulability. We aim to explore the association between ischemic stroke and portal vein thrombosis in liver cirrhosis. Study Design and Methods. We selected patients from our prospectively established database of liver cirrhosis from December 2014 to July 2019. The difference between patients with and without stroke was compared. A 1 : 1 propensity score matching (PSM) analysis was performed to adjust the effect of age, sex, Child-Pugh score, and MELD score on our statistical results.

RESULTS

There were 349 cirrhotic patients in the cross-sectional study. The prevalence of stroke, ischemic stroke, hemorrhagic stroke, and portal vein thrombosis was 8.88% (31/349), 8.31% (29/349), 1.15% (4/349), and 28.65% (100/349) in liver cirrhosis, respectively. Patients with ischemic stroke were significantly older and had significantly higher proportions of alcohol abuse, smoking, and arterial hypertension and higher levels of white blood cell and low-density lipoprotein. However, statistical analyses with and without PSM did not find any significant association between ischemic stroke and portal vein thrombosis in patients with liver cirrhosis.

CONCLUSION

Ischemic stroke might not be associated with portal vein thrombosis in liver cirrhosis.

Clinical characteristics and prognosis of cerebral venous thrombosis in Chinese women during pregnancy and puerperium

Due to the specific physiology associated with pregnancy and puerperium, cerebral venous sinus thrombosis (CVT) may manifest different characteristics. This study aimed to identify the clinical manifestations and prognosis of pregnancy-associated CVT. A total of 43 pregnancy-associated CVT patients were enrolled. We analysed the clinical presentations of the disease and performed a multivariate logistic regression analysis to determine which variables were associated with prognosis. Our descriptive results showed the following: 1) the incidence was 202 per 100,000 deliveries, and the mortality rate was 11.63%; 2) the most frequent symptom was headache; 3) the most frequent abnormal laboratory findings were increased levels of fibrinogen and several serum lipoproteins (including triglyceride, cholesterol, high-density lipoprotein, low-density lipoprotein, apolipoprotein A1, and apolipoprotein B); and 4) the superior sagittal sinus and transverse sinus were the most frequently affected locations. Moreover, an increased modified Rankin Scale score was positively associated with infection, seizure, intracerebral haemorrhage (ICH) and hypertensive disorders of pregnancy (HDP). Comparably, the occurrence of death was positively and significantly associated with infection, seizure and ICH. Consequently, timely diagnosis and treatment of pregnancy-associated CVT patients with infection, seizure, ICH or HDP are needed. Patients with infection, seizure or ICH have a greater risk of death.

Factor V Leiden

Factor V Leiden (FVLeiden ) is a common hereditary thrombophilia that causes activated protein C (APC) resistance. This review describes many of the most fascinating features of FVLeiden , including background features, mechanisms of hypercoagulability, the founder mutation concept, the "FVLeiden paradox," synergistic interaction with other thrombotic risk factors, the intertwined relationship between FVLeiden and APC resistance testing, and other, uncommon mutations implicated in causing APC resistance. In addition, there are several conditions where laboratory tests for APC resistance and FVLeiden are or can be discrepant, including lupus anticoagulants, anticoagulants such as direct thrombin inhibitors (dabigatran, argatroban, and bivalirudin) and rivaroxaban, as well as pseudohomozygous, pseudo-wildtype, liver transplant, and bone marrow transplant patients. The laboratory test error rate for FVLeiden is also presented.

Activated protein C resistance testing for factor V Leiden

Activated protein C resistance assays can detect factor V Leiden with high accuracy, depending on the method used. Factor Xa inhibitors such as rivaroxaban and direct thrombin inhibitors including dabigatran, argatroban, and bivalirudin can cause falsely normal results. Lupus anticoagulants can cause incorrect results in most current assays. Assays that include dilution into factor V-deficient plasma are needed to avoid interference from factor deficiencies or elevations, which can arise from a wide variety of conditions such as warfarin, liver dysfunction, or pregnancy. The pros and cons of the currently available assays are discussed.

Evaluation of antiphospholipid antibodies in youths suffering from cerebral ischemia

OBJECTIVE

Cerebral stroke in young adults is not uncommon. Venous thromboses resulting from antiphospholipid antibodies (APAs) are one of causes of stroke in youths. This study aimed at evaluating the role of APAs in young patients with ischemic strokes.

METHODS

In this case-control study, 25 patients with diagnosis of ischemic stroke or transient ischemia attack in case group and 40 patients in control group were studied during one year. Medical history was obtained from all the patients. Levels of anticardiolipin and antiphospholipid antibodies including both IgG and IgM, were evaluated in all patients before consuming warfarin and using ELISA method.

RESULTS

Antiphospholipid antibodies or anticardiolipin antibody was high in six (24%) patients. In the control group, only two subjects had abnormally increased amounts of at least one antibody. The difference was significant between the case and control groups (P < .05). The study demonstrated that history of at least one cerebral ischemic event was observed in two out of 6 patients (33.3%) with high APAs and two out of 19 patients (10.5%) without higher APAs.

CONCLUSION

APAs increase risk of ischemic strokes independently or in association with other vascular risk factors.

Active tissue factor and activated factor XI in patients with acute ischemic cerebrovascular events

BACKGROUND

  Elevated factor (F)XI and tissue factor (TF) have been reported to occur in patients with acute ischemic stroke (AIS). We sought to investigate whether circulating activated FXI (FXIa) and TF on admission can predict clinical outcomes in patients with acute cerebrovascular events.

MATERIALS AND METHODS

  In the observational study, we evaluated 205 consecutive patients aged 70 years or less within the first 72 h of acute event, including 140 with AIS and 65 with transient ischemic attack (TIA). Plasma TF and FXIa activity were determined on admission in clotting assays by measuring the response to inhibitory monoclonal antibodies.

RESULTS

Active TF and FXIa activity were detected in 58 (28·9%) and 132 (64·4%) patients on admission, respectively. Active TF was detected in 45 of the 136 AIS patients with available TF levels (33·1%) and 13 of the 65 patients with acute TIA (20%; 0·05). Corresponding values for FXIa were 99 of the 140 (70·7%) and 33 of the 65 (50·8%; P= 0·006), respectively. Patients with detectable TF were more frequently women and hypertensive, while subjects with detectable FXIa had more often diabetes and higher levels of fibrinogen, C-reactive protein and interleukin-6 (all P < 0·05). Patients with detectable FXIa but not TF had higher National Institutes of Health Stroke Scale score, higher modified Rankin scale score and lower Barthel Index at discharge (all P < 0·05).

CONCLUSIONS

Circulating active TF and FXIa occur frequently in acute cerebrovascular ischemic events. Active FXIa in plasma might be useful as a novel risk marker of worse functional outcomes in patients with acute cerebrovascular events.

Acquired activated protein C resistance caused by lupus anticoagulants

Lupus anticoagulants (LA) can cause acquired activated protein C resistance (APC-R), but the clinical significance is unclear. To investigate thrombosis and acquired APC-R in patients with LA, we enrolled all 132 patients undergoing hypercoagulability testing with positive LA results and in whom APC-R (with factor V-deficient plasma) was performed during a 2.5-year period. Among 121 patients without factor V Leiden, 24.0% had acquired APC-R; retrospective and prospective (mean follow-up, 2.0 years) thrombotic events were analyzed. The distribution of venous vs arterial thrombosis was different for APC-R vs no APC-R (P = .0064). The majority (19/29 [66%]) with acquired APC-R experienced venous thrombosis, whereas a minority experienced arterial thrombosis (9/29 [31%]; P = .017). The opposite pattern occurred among patients without APC-R (arterial thrombi more common than venous thrombi). After excluding thrombotic events more than 5 years from a positive LA test, venous thrombosis occurred in 62% with (18/29) vs 32% without (29/92) APC-R (P = .0045); and arterial thrombosis in 28% with (8/29) vs 51% without (47/92) APC-R (P = .033). Patients with acquired APC-R due to LA had more venous thrombosis than did patients with LA without APC-R and experienced venous more often than arterial thrombosis.

Inherited thrombophilia in childhood arterial stroke: data from Lebanon

Pediatric ischemic stroke still represents a burden, and more than half of the survivors will experience cognitive or motor disabilities. The objective of this study was to investigate the role of thrombophilia in a cohort of children with arterial ischemic stroke. The records of infants and children with clinically and radiologically confirmed stroke were reviewed. Patients with venous or perinatal stroke were not included. Thirty-three patients were diagnosed with arterial ischemic stroke. The male/female ratio was 1.75:1. The median age was 4 years. The most frequent clinical manifestations were hemiparesis (54.5%) and seizures (33.3%). Genetic thrombophilia testing was available on 24 patients. Nine of the 24 patients (37.5%) were heterozygous for factor V Leiden. None of the patients carried the factor II G20210A variant. Ten patients (41.7%) were heterozygous and 3 (12.5%) were homozygous for methylenetetrahydrofolate reductase (MTHFR) C677T variant. Fifteen patients (62.5%) had one or more genetic polymorphism. Factor V Leiden was significantly associated with arterial ischemic stroke (P < 0.001). Stroke recurred in 2 children with multiple risk factors and MTHFR C677T mutation. Factor V Leiden is one of the major genetic risk factors for pediatric arterial ischemic stroke in Lebanon. MTHFR C677T was prevalent among patients with recurrent stroke.

Risk factors for ischemic stroke and transient ischemic attack in patients under age 50

To analyze risk factors for ischemic stroke and transient ischemic attack (TIA) in young adults under the age of 50. To make recommendations for additional research and practical consequences. From 97 patients with ischemic stroke or TIA under the age of 50, classical cardiovascular risk factors, coagulation disorders, history of migraine, use of oral contraceptives, cardiac abnormalities on ECG and echocardiography, and the results of duplex ultrasound were retrospectively analyzed. Literature was reviewed and compared to the results. 56.4% of the patients had hypertension, 12.1% increased total cholesterol, 20% hypertriglyceridemia, 31.5% an increased LDL-level, 32.6% a decreased HDL-level and 7.2% a disturbed glucose tolerance. Thrombophilia investigation was abnormal in 21 patients and auto-immune serology was abnormal in 15 patients. Ten of these patients were already known with a systemic disease associated with an increased risk for ischemic stroke (i.e. systemic lupus erythematosus). The ECG was abnormal in 16.7% of the cases, the echocardiography in 12.1% and duplex ultrasound of the carotid arteries was in 31.8% of the cases abnormal. Conventional cardiovascular risk factors are not only important in patients over the age of 50 with ischemic stroke or TIA, but also in this younger population under the age of 50. Thrombophilia investigation and/ or autoimmune serology should be restricted to patients without conventional cardiovascular risk factors and a history or other clinical symptoms associated with hypercoagulability and/ or autoimmune diseases.

A review of hereditary and acquired coagulation disorders in the aetiology of ischaemic stroke

The diagnostic workup in patients with ischaemic stroke often includes testing for prothrombotic conditions. However, the clinical relevance of coagulation abnormalities in ischaemic stroke is uncertain. Therefore, we reviewed what is presently known about the association between inherited and acquired coagulation disorders and ischaemic stroke, with a special emphasis on the methodological aspects. Good-quality data in this field are scarce, and most studies fall short on epidemiological criteria for causal inference. While inherited coagulation disorders are recognised risk factors for venous thrombosis, there is no substantial evidence for an association with arterial ischaemic stroke. Possible exceptions are the prothrombin G20210A mutation in adults and protein C deficiency in children. There is proof of an association between the antiphospholipid syndrome and ischaemic stroke, but the clinical significance of isolated mildly elevated antiphospholipid antibody titres is unclear. Evidence also suggests significant associations of increased homocysteine and fibrinogen concentrations with ischaemic stroke, but whether these associations are causal is still debated. Data on other acquired coagulation abnormalities are insufficient to allow conclusions regarding causality. For most coagulation disorders, a causal relation with ischaemic stroke has not been definitely established. Hence, at present, there is no valid indication for testing all patients with ischaemic stroke for these conditions. Large prospective population-based studies allowing the evaluation of interactive and subgroup effects are required to appreciate the role of coagulation disorders in the pathophysiology of arterial ischaemic stroke and to guide the management of individual patients.

Screening for coagulation disorders in patients with ischemic stroke

The role of coagulation disorders in the pathogenesis of (recurrent) ischemic stroke is uncertain. Therefore, the clinical utility of screening patients with ischemic stroke for these conditions and the therapeutic implications of a detected coagulation disorder in a patient who experienced ischemic stroke are uncertain. We reviewed the currently available data on the relationship between various inherited and acquired coagulation abnormalities (factor V Leiden and prothrombin G20210A mutations, deficiencies of protein C, protein S and anti-thrombin, hyperhomocysteinemia, the antiphospholipid syndrome and increased levels of fibrinogen) and ischemic stroke. Based on the existing evidence we discuss the usefulness of screening stroke patients for prothrombotic conditions and current recommendations regarding the optimal management of ischemic stroke patients in whom a coagulation disorder is found.

Testing for Inherited Thrombophilias in Arterial Stroke

Background and Purpose— Despite a paucity of evidence supporting a true association of ischemic stroke and the inherited thrombophilias, it is common practice for many neurologists to order these tests as part of the work-up of ischemic stroke, especially in young patients. Treatment with oral anticoagulation is often used in patients with positive results for the inherited thrombophilias.

Methods— We reviewed the literature focusing on case-control studies of the 5 most commonly inherited disorders of coagulation: protein C deficiency, protein S deficiency, antithrombin deficiency, and the factor V Leiden and prothrombin gene mutations in patients with stroke. We also analyzed the available data on stroke patients with inherited thrombophilia and patent foramen ovale.

Results— Multiple case-control studies have not convincingly shown an association of the inherited thrombophilias with ischemic stroke, even in young patients and patients with patent foramen ovale.

Conclusion— If there is an association between the inherited thrombophilias and arterial stroke, then it is a weak one, likely enhanced by other prothrombotic risk factors. The consequences of ordering these tests and attributing causality to an arterial event can result in significant costs to the health care system and pose a potential risk to patients, because this may lead to inappropriate use of long-term oral anticoagulants, exposing patients to harm without a clearly defined benefit.

Death after liposuction: case report and review of the literature

We report the case of a 41-year-old woman who died after surgical intervention for liposuction. The case was studied by a methodological approach including examination of clinical records and documentation, analysis of anatomo-histopathological findings and evaluation of physicians' behaviour. Autopsy excluded the lethal complications most frequently associated with liposuction (pulmonary embolism, sepsis, necrotizing fasciitis, perforation of abdominal organs) and identified the cause of death as 'massive necrosis of brain-stem and cerebellum, due to spontaneous thrombosis of the basilar and cerebellar district'. Analysis of the physicians' behaviour, together with a review of the literature, excluded medical errors or malpractice. The Court of Law ruled the death as a fatal unforeseeable complication of the operation. The medico-legal interest of the case lies in the singular anatomo-pathological cause of death, discussed in relation to the hypothesis of professional responsibility after surgical intervention for liposuction.

Laboratory tests for protein C deficiency

Hereditary protein C deficiency is a hypercoagulable state associated with an increased risk for venous thrombosis. The recommended initial test for protein C is an activity (functional) assay, which may be clotting time based or chromogenic. The advantages and disadvantages of the various testing options are presented. The causes of acquired protein C deficiency are much more common than hereditary deficiency. Therefore, this article describes the appropriate steps to take when protein C activity is low, to confirm or exclude a hereditary deficiency. The causes of falsely normal results are also described, including lupus anticoagulants and direct thrombin inhibitors.

Role of coagulation factors in cerebral venous sinus and cerebral microvascular thrombosis

OBJECTIVE

The objective of this study was to define the relative contributions of three major pro- and anti-coagulation pathways (heparin-antithrombin, protein C, and tissue factor (TF)) in the thrombogenic responses that occur in large and small vessels of the brain.

METHODS

Cerebral venous sinus thrombosis was induced by topical application of FeCl3 on the superior sagittal sinus, while photoactivation of fluorescein was used to induce thrombus formation in cerebral microvessels. Heparin, activated protein C (APC), and antibodies to either APC or TF were used to assess thrombogenesis in wild-type mice. Mutant mice that overexpress the endothelial protein C receptor (EPCR-tg) or with TF deficiency in Tie2-expressing endothelial cells (LTFE) were also used.

RESULTS

Thrombus formation in the superior sagittal sinus of wild-type mice was attenuated by heparin and in EPCR-tg mice, while treatment with the APC antibodies enhanced thrombogenesis. Arteriolar thrombosis was largely unresponsive to the interventions studied. However, in cerebral venules, thrombosis was inhibited by heparin and in EPCR-tg mice. TF antibody treatment also inhibited venular thrombosis, with a similar attenuation noted in LTFE mice.

CONCLUSION

Thrombin promotes while the APC pathway blunts thrombus formation in an experimental model of cerebral venous sinus thrombosis. TF involvement is more evident in cerebral microvascular thrombogenesis, with endothelial cell-associated TF mediating this response in venules, but not arterioles.

Prognostic values of lesion volume and biochemical markers in ischemic and hemorrhagic stroke: a stereological and clinical study

PURPOSE

Our aim was to evaluate the relationship between lesion volume, serum level of biochemical markers, and clinical situation in ischemic and hemorrhagic stroke.

METHODS

MRI was obtained on 33 ischemic and 28 hemorrhagic strokes. The Cavalieri method was used to measure the volume. To evaluate neurological situation of the patients, we used the National Institutes of Health Stroke Scale (NIHSS) and Rankin Disability Scores at the first, third, seventh, and thirtieth days. We measured the level of leptin, high sensitivity C-reactive protein (hs-CRP), insulin, cortisol, fibrinogen, protein C, protein S, von Willebrand factor, D-dimer, Antitrombin III, and Factor VIII (F VIII) at the same time intervals.

RESULTS

In ischemic events, cortisol level at third and seventh days, and fibrinogen level at the first day were correlated with lesion volumes (r = 0.5, p = .02; r = 0.4, p = .02; r = 0.5, p = .005, respectively). In hemorrhagic events, only fibrinogen level was correlated with lesion volumes at third day (r = 0.6, p = .04). No significant differences were found among all these biochemical parameters, neurological situation (p > .05), and lesion volumes at all times.

CONCLUSION

In the prediction of stroke prognosis, lesion volume and all of the evaluated biochemical parameters are not deterministic factors.

Transient ischemic attack: diagnostic evaluation

A transient ischemic attack portends significant risk of a stroke. Consequently, the diagnostic evaluation in the emergency department is focused on identifying high-risk causes so that preventive strategies can be implemented. The evaluation consists of a facilitated evaluation of the patient's metabolic, cardiac, and neurovascular systems. At a minimum, the following tests are recommended: fingerstick glucose level, electrolyte levels, CBC count, urinalysis, and coagulation studies; noncontrast computed tomography (CT) of the head; electrocardiography; and continuous telemetry monitoring. Vascular imaging studies, such as carotid ultrasonography, CT angiography, or magnetic resonance angiography, should be performed on an urgent basis and prioritized according to the patient's risk stratification for disease. Consideration should be given for echocardiography if no large vessel abnormality is identified.

Testing for hereditary thrombophilia: a retrospective analysis of testing referred to a national laboratory

Background

Predisposition to venous thrombosis may be assessed through testing for defects and/or deficiencies of a number of hereditary factors. There is potential for confusion about which of these tests are appropriate in which settings. At least one set of recommendations has been published to guide such testing, but it is unclear how widely these have been disseminated.

Methods

We performed a retrospective analysis of laboratory orders and results at a national referral laboratory to gain insight into physicians' ordering practices, specifically comparing them against the ordering practices recommended by a 2002 College of American Pathologists (CAP) consensus conference on thrombophilia testing. Measurements included absolute and relative ordering volumes and positivity rates from approximately 200,000 thrombophilia tests performed from September 2005 through August 2006 at a national reference laboratory. Quality control data were used to estimate the proportion of samples that may have been affected by anticoagulant therapy. A sample of ordering laboratories was surveyed in order to assess potential measurement bias.

Results

Total antigen assays for protein C, protein S and antithrombin were ordered almost as frequently as functional assays for these analytes. The DNA test for factor V Leiden was ordered much more often than the corresponding functional assay. In addition, relative positivity rates coupled with elevations in prothrombin time (PT) in many of these patients suggest that these tests are often ordered in the setting of oral anticoagulant therapy.

Conclusion

In this real-world setting, testing for inherited thrombophilia is frequently at odds with the recommendations of the CAP consensus conference. There is a need for wider dissemination of concise thrombophilia testing guidelines.