PREDICTIVE VALUE OF ANTIPHOSPHOLIPID ANTIBODIES IN THE ACUTE PHASE OF DEEP VEIN THROMBOSIS
- Katja Perdan Pirkmajer, Slovenia
Abstract
Background and Aims
Antiphospholipid syndrome (APS) is an important cause of deep vein thrombosis (DVT), but can be diagnosed by positive antiphospholipid (aPL) test only 24 weeks after DVT. Anticoagulation is usually stopped 3 months after the first DVT episode, which might increase the risk for recurrence in subjects with undiagnosed APS. We evaluated whether APS could be detected by measuring aPL immediately after DVT occurrence.
Methods
196 patients (85 female, 54±2 years) with acute DVT received anticoagulation for 3 months. aPL (aCL IgG/IgM and anti-β2GPI IgG/IgM/IgA) were determined at DVT occurrence and every 4 weeks until week 24. Medium/high aCL titer and/or presence of anti-β2GPI at 24 weeks confirmed APS.
Results
Ultimately, 20/196 (10.2%) patients fulfilled APS classification criteria. Among these, 15/20 (75%) patients had medium or high titer aPL at the time of acute. Two patients (10%) had low positive aCL IgG and one had low titer aCL IgM. Two patients (10%) were negative for aPL, but had later fulfilled APS criteria due to positive LA. Medium/high aCL and/or presence of anti-β2GPI at inclusion had 83% specificity and 90.5% sensitivity for APS. Absence of aPL at inclusion had a negative predictive value of 98.6%.
Conclusions
Here we show that in acute phase of DVT, positive medium or high titer aCL IgG/IgM or anti-β2GPI is suggestive of APS. In these patients continuation of anticoagulation beyond the initial 3 months should be considered.