Antiphospholipid syndrome and asymptomatic carriers of antiphospholipid antibody: prospective analysis of 404 individuals.

OBJECTIVE: We carried out a prospective analysis of clinical and analytical findings in individuals with antiphospholipid antibodies (aPL).

METHODS: We prospectively studied 404 individuals, classified in 2 groups: (1) patients with primary or secondary antiphospholipid syndrome (APS, n = 226); and (2) asymptomatic carriers of aPL (n = 178). Patients with APS and thrombosis were treated with dicumarin, and an international normalized ratio around 3.0 (range 2.5-3.5) was targeted. Asymptomatic carriers were not treated, but specific prophylaxis with low molecular weight heparin or aspirin was prescribed for the periods when individuals were at increased risk of thrombosis. Both groups of individuals were followed up at semester intervals for 36 months.

RESULTS: Patients with APS presented with venous (n = 106, 46.9%) and/or arterial (n = 70. 31%) thrombosis or fetal loss (n = 58 out of 112 women of fertility age, 51.8%). At the time of the first thrombotic event, 50.0% of patients with APS had coincident risk factors for thrombosis (previous surgery and prolonged immobilization were significantly associated with venous thrombosis, and hypercholesterolemia and arterial hypertension with arterial thrombosis). Eighteen patients with APS died during the study period. Recurrence of thrombosis in patients with APS was linked to insufficient anticoagulation. During the followup, no episode of thrombosis was detected in any asymptomatic carrier. The proportion of subjects with aPL was similar in patients and in asymptomatic carriers. The proportion of subjects with aPL decreased during the followup, in both patients and carriers.

CONCLUSION: Differences between patients and asymptomatic carriers with aPL are at least partially dependent on the proportion of coincident vascular risk factors. The decline in aPL during the followup defines a subgroup in which an anticoagulation suppression assay could be tried.