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Diagnosis, risk-stratification, and management of patients with antiphospholipid antibody syndrome (and/or lupus anticoagulant)
Henry I. Bussey, Pharm.D.
Two recent publications provide useful guidance to diagnose, risk-stratify, and manage patients with antiphospholipid antibody syndrome (and/or lupus anticoagulant).
The two articles are:
Miyakis S, Lockshin MD, Atsumi T, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost 2006; 4:205-306.
Ortel T L. Thrombosis and the antiphospholipid syndrome. (in) Hematology 2005; American Society of Hematology Education Program Book, pg. 462-468 available at http://www.asheducationbook.org/ cgi/content/full/2005/1/462? maxtoshow=&HITS=10&hits=10&RESULTFORMAT= &fulltext=Antiphospholipid&searchid=1& FIRSTINDEX=0&volume=2005&issue=1&resourcetype=HWCIT
The first article addresses the complex challenge of making an accurate diagnosis of antiphospholipid antibody syndrome (APS) which, until recently, was guided by the Sapporo classification criteria of 1999. Early in 2006, a large international group of experts published a consensus statement to update the Sapporo criteria. The complexity of information in this publication exceeds what can be outlined here, but a few key points will be highlighted. Anyone involved in the diagnosis and/or risk-stratification of APS patients is encouraged to review carefully the entire report.
As in the previous criteria, the diagnosis of APS is dependent on the presence of at least one of the clinical criteria and at least one of the laboratory criteria. The clinical criteria (which are defined in substantial detail in the report) include vascular thrombosis or pregnancy morbidity. The laboratory criteria include a positive test for lupus anticoagulant (LA), IgG and/or IgM anticardiolipin antibody (aCL), and IgG and/or IgM beta-2 glycoprotein-I antibody. The latter laboratory criterion is a new addition to the criteria. Also, in the previous criteria it was recommended that a second confirmatory test be required at least 6 weeks after the first positive test. The new criteria call for the two tests to be at least 12 weeks apart since an initial elevation in any of these tests may be transitory and/or related to the acute event. It also should be noted that IgA antibodies are not included in the classification criteria.
The report also discusses clinical and laboratories "features" that may be important in the risk stratification but are not diagnostic criteria. These other tests and "features" include (1) heart valve disease, (2) livedo reticularis, (3) thrombocytopenia, (4) nephropathy, (5) neurological manifestations, (6) IgA aCL, (7) IgA beta-2 glycoprotein-I antibody, (8) antiphosphatidylserine antibodies (aPS), (9) antiphosphatidylethanolamine antibodies (aPE), (10) prothrombin alone antibodies (aPT-A), and (11) phosphatidylserine-prothrombin complex antibodies (aPS/PT). These "features", which are considered non-diagnostic criteria, may create two interesting situations: (1) a patient may fulfill the clinical criteria but have only a non-criteria laboratory "feature" or (2) a patient may have a non-criteria clinical "feature" and a diagnostic laboratory finding. In such cases, it was concluded that non-criteria features should not be used to make the diagnosis of APS but rather such patients should be classified as having "probable APS", "features associated with APS", or "non-criteria features of APS" and included in future clinical trials in order to help generate data to provide further clarification of the importance of these "features."
The second article provides an overview and personal insight from one of the leading authorities in the area of APS. Among the controversial treatment issues addressed in this paper are (1) should an INR target higher than 2 to 3 be used for some or all APS patients with thrombosis, (2) should aspirin - alone on in combination with warfarin - be used in APS patients with arterial thrombosis, (3) how should APS patients with recurrent thrombosis be managed, (4) how should one deal with the potential that APS may falsely elevate the INR, (5) how long should anticoagulation be continued in a patient with APS and thrombosis, and (6) should asymptomatic patients with aPL be treated? At the end of the article, the author provides an overview of his own practices regarding:
When to test for aPL antibodies
Treating APS patients with initial venous thromboembolism to an INR of 2.5 for at least 12 months, but for recurrent VTE he uses a target INR of 3.5 or changes to an alternative anticoagulant.
Treating APS patients with initial arterial thromboembolism to an INR of 3.0 for a minimum of 12 months, but for recurrent arterial thromboembolism he uses a target INR above 3 or adds an antiplatelet agent, uses an alternative anticoagulant, or considers immunomodulatory strategy.
Uses the chromogenic factor X assay in place of the INR for those instances in which the aPL antibody causes a false elevation in the INR. A pre-anticoagulation INR is suggested in order to identify those in whom a false elevation may be present; and it is pointed out that more sensitive reagents may yield a greater prolongation in the INR.
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