Anticardiolipin antibodies (ACLAs) and the lupus anticoagulant (antiphospholipid antibodies) are risk factors for atherothrombosis, and arterial and venous thrombotic events. ACLAs are significant independent risk factors for myocardial infarction, myocardial reinfarction, and thromboembolic events after acute myocardial infarction and after focal cerebral ischemia. After transluminal coronary angioplasty, restenosis with recurrent ischemia occurs earlier and more frequently in antiphospholipid antibody-positive patients than in antiphospholipid antibody-negative patients. Long-term anticoagulation in patients with antiphospholipid antibodies syndrome is still controversial, but some experts recommend long-term anticoagulation therapy with an International Normalized Ratio maintained at 3 or higher.

Glueck and associates looked at patients with hyperlipidemia to determine whether ACLA immunoglobulin-G (IgG) and IgM were independent risk factors for atheroscle-rotic vascular disease. In each of the 864 patients, based on their prior history, atherosclerotic vascular disease was characterized by one or more of the following events: unstable angina, myocardial infarction, angioplasty, coronary artery bypass surgery, claudication, transient ischemic attack and ischemic stroke. Multiple laboratory tests, including ACLA IgG and IgM, were performed in all patients.

Patients with atherosclerotic vascular disease events had lower high-density lipoprotein and higher ACLA IgM levels. ACLA IgG did not differ between event and nonevent groups. Other significant independent risk factors for atherosclerotic vascular disease included age, diabetes, male sex and hypertension. ACLA IgM was a significant independent risk factor for any event at 55 or more years of age.

The authors conclude that ACLAs IgG and IgM are major independent risk factors for atherosclerotic vascular disease and should be routinely measured as ancillary atherothrombotic risk factors in all patients with atherosclerotic vascular disease events, patients at high risk for atherosclerotic vascular disease and patients in whom thrombosis is a major pathoetiology. Because coumadin can reduce thrombotic and atherothrombotic events in patients with antiphospholipid syndrome, trials are needed to evaluate the efficacy and safety of coumadin anticoagulation in patients with high ACLAs and atherosclerotic vascular disease.