Single Center Review of Clinicopathological Characterization in 77 Patients with Positive Lupus Anticoagulant Antibodies

Abstract

Background: The antiphospholipid syndrome (APS) is a thrombophillic disorder characterized by the presence of antiphospholipid antibodies (APA). It often occurs in patients with systemic lupus erythematosus (SLE) and may be associated with recurrent abortions and thrombocytopenia and, occasionally, catastrophic thrombotic events.

Objectives: To examine, retrospectively, the clinico-pathological features of patients with APS detected by the presence of the lupus anticoagulant (LAC).

Methods: Patients were selected for study on the basis of a positive LAC test on review of the laboratory computer records of the King Faisal Specialist Hospital and Research Center. Following this, a clinical chart review was conducted in order to determine the clinical presentations, treatment and the course of patients identified. The information obtained was entered into an electronic database and subsequently analyzed.

Results: Seventy-seven patients were identified and reviewed. Fifty-six (73%) were female and 16 (21%) were children less than 15-years-old. Thirty-two patients (42%) had no clinical events (incidental APS). The syndrome was classified as primary in 40 (52%) patients and secondary in 37 (48%). Out of the 45 (58%) patients who presented with symptoms related to APA 22 (49%) had thrombosis, 24 (53%) had pregnancy failure, and 4 (9%) presented with catastrophic APS. The activated partial thromboplastin time (aPTT) was elevated and not corrected by mixing with normal plasma in 47 (61%). On the other hand, the prothrombin time (PT) was normal in 66 (90%). There is a significant difference between aPTT and PT as a screening test with P value of < 0.0001. Tests for anticardiolipin antibodies (ACA) were positive in 39 patients (70%). Only 13 (17%) patients had thrombocytopenia. All patients who presented with thrombosis were treated with warfarin but only 5 (23%) had received aspirin. Out of the 22 patients presenting with thrombosis, 12 (55%) had one or more recurrent thrombotic events while only 6 (25%) out of the 24 patients who presented with pregnancy failure had events other than pregnancy failure. Fifty-two patients were followed up regularly and were alive.

Conclusions: We find that thrombosis, venous or arterial, and obstetric complications are the most frequent clinical findings in our patients with circulating LAC. Incidental APS is not an uncommon finding in patients screened for APS. There is a clear association between the presence of LAC and an abnormal aPTT, which is much less obvious with the PT.

Keywords:

• Systemic lupus erythematosus
• Antiphospholipid syndrome
• Antiphospholipid antibodies
• Lupus anticoagulant