Anticardiolipin antibodies are not an independent risk factor for stroke: an incident case-referent study nested within the MONICA and Västerbotten cohort project

Laboratory evaluation of hypercoagulability with venous or arterial thrombosis

OBJECTIVE

To provide recommendations for hypercoagulation testing for patients with venous, arterial, or neurovascular thrombosis, as reflected in the medical literature and the consensus opinion of recognized experts in the field.

DATA SOURCES, EXTRACTION, AND SYNTHESIS

The authors extensively examined the literature and current practices, and prepared a draft manuscript with preliminary recommendations. The draft manuscript was circulated to each of the expert participants (n = 30) in the consensus conference prior to the convening of the conference. The manuscript and recommendations were then presented at the conference for discussion. Recommendations were accepted if a consensus of the 28 experts attending the conference was reached. The discussions were also used to revise the manuscript into its final form.

CONCLUSIONS

The resulting article provides 17 recommendations for hypercoagulation testing in the setting of venous, arterial, or neurovascular thrombosis. The supporting evidence for test selection is analyzed and cited, and consensus recommendations for test selection are presented. Issues for which a consensus was not reached at the conference are also discussed.

Phospholipid autoantibodies: time for a new immuno-assay?

Antiphospholipid (aPL) antibodies are a wide and heterogeneous group of closely related immunoglobulins that have specificity for a number of phospholipids (PLs), PL-binding proteins, including beta2 glycoprotein I (beta2GP1), prothrombin, and PL-protein complexes. Antiphospholipid antibodies are currently detected by a standard solid-phase immunoassay such as anticardiolipin (aCL) antibodies. Although the association between aCL antibodies and thrombosis is well recognized, their role in stroke pathogenesis, and the possibility that they are an independent stroke risk factors in the general stroke population, remains to be determined. There are other negatively charged PL, largely represented within the cellular membrane and involved in the coagulation. Different studies have demonstrated a positive correlation among other aPL and stroke.

Elevated levels of Factor XI are associated with cardiovascular disease in women

Coronary artery disease (CAD) continues to be the most frequent cause of death among women in the United States. Although elevated levels of clotting factors have been associated with CAD, few of these studies have been performed in women. Elevated levels of Factor XI have previously been associated with venous thrombosis, but little is known about its effect on arterial thrombosis. We selected women referred for cardiac catheterization who were found to have either normal coronaries or evidence of severe CAD and compared levels of homocysteine, anticardiolipin IgG/IgM antibodies, fibrinogen, platelet count, Factor VII, Factor VIII and Factor XI. Women with severe CAD had significantly higher levels of Factor XI than those without CAD (128% vs. 82%, p<0.04). Statistical adjustment for age, diabetes, hypertension, total cholesterol (TC), current smoking, or BMI had no effect on the independent association between CAD status and Factor XI. Factor XI was higher in women with total cholesterol levels >6.18 mmol/l (>239 mg/dl) compared with normocholesteremic women and was also higher in the upper tertile of age, but even when adjusted for these, the association remained significant. This initial study suggests that Factor XI may be an important parameter in arterial as well as venous thrombosis.

Hughes syndrome crosses boundaries

Hughes (antiphospholipid) syndrome is a condition in continuous evolution. Since it was first described almost 20 years ago, significant advances in its diagnosis and management have been made. Recently, classification criteria for definite antiphospholipid syndrome have been proposed and validated. However, there is still controversy regarding issues such as the utility of new diagnostic tests (detecting antibodies to beta(2)-glycoprotein I, phospholipids other than cardiolipin or phospholipid mixtures), the role of antiphospholipid antibodies in neurological conditions such as demyelinating disease, cognitive impairment or migraine and the optimal management of thrombosis and obstetric manifestations. These are all briefly discussed in this review.

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.

Presumed pre- or perinatal arterial ischemic stroke: risk factors and outcomes

A subgroup of children with arterial ischemic stroke in the pre- or perinatal period present with delayed diagnosis. We identified 22 children who met the following criteria: (1) normal neonatal neurological history, (2) hemiparesis and/or seizures first recognized after two months of age, and (3) computed tomography or magnetic resonance imaging showing remote cerebral infarct. Laboratory evaluations included protein C, protein S, antithrombin, activated protein C resistance screen (APCR), Factor V Leiden (FVL), prothrombin gene defect, methylene tetrahydrofolate reductase variant (MTHFR), anticardiolipin antibody (ACLA), and lupus anticoagulant. Not all children received all tests. Age at last visit ranged from 8 months to 16.5 years (median 4 years). Twelve were boys. Fourteen had left hemisphere infarcts. Median age at presentation was 6 months. Eighteen had gestational complications. Fourteen children had at least transient coagulation abnormalities (ACLA = 11, ACLA + APCR = 1, APCR = 2 with FVL + MTHFR = 1); six of these children had family histories suggestive of thrombosis. Cardiac echocardiogram was unremarkable in the 15 tested. Outcomes included persistent hemiparesis in 22; speech, behavior, or learning problems in 12; and persistent seizures in five, with no evidence of further stroke in any patient. The persistence and importance of coagulation abnormalities in this group need further study.

Neurologic manifestations of the antiphospholipid syndrome

Neurologic disorders are among the most prominent clinical manifestations associated with the antiphospholipid syndrome. Such neurologic disorders are predominantly related to focal central nervous system thrombo-occlusive events. This review summarizes the latest data regarding the clinical aspects of stroke and other neurologic manifestations associated with antiphospholipid antibodies.

Heterogeneity of autoantibodies against cardiolipin and oxidatively modified LDLs revealed by human monoclonal antibodies

Human monoclonal antibodies against cardiolipin, native and oxidatively modified LDL and against apoB100 were obtained by Epstein-Barr virus transformation of peripheral blood mononuclear cells followed by cloning. The antibodies were used to analyse the cross-reactivity between monoclonals with different specificities and to study the repertoire of antibodies present in sera from patients. Monoclonal antibodies selected for binding to cardiolipin were the least cross-reactive, whereas antibodies against different modifications of LDL frequently also reacted with other modifications. Inhibition studies showed that serum antibodies against cardiolipin and against oxidatively modified LDL were to a different extent inhibited by the different monoclonal antibodies and thus markedly heterogeneous.