Possible relationship between antiphospholipid antibodies and embolic events in infective endocarditis

Abstract

ObjectiveAntiphospholipid (aPL) antibodies may activate platelets and contribute to vegetation growth and embolisation in infective endocarditis (IE). We aimed to determine the value of aPL as predictors of embolic events (EE) in IE.MethodsWe studied 186 patients with definite IE (Duke-Li criteria, all types of IE) from the Nanc-IE prospective registry (2007–2012) who all had a frozen blood sample and at least one imaging procedure to detect asymptomatic or confirm symptomatic EE. Anticardiolipin (aCL) and anti-β2-glycoprotein I (β2GPI) antibodies (IgG and IgM) were assessed after the end of patients’ inclusion. The relationship between antibodies and the detection of EE after IE diagnosis were studied with Kaplan-Meier and Cox multivariate analyses.ResultsAt least one EE was detected in 118 (63%) patients (52 cerebral, 95 other locations) after IE diagnosis in 80 (time interval between IE and EE diagnosis: 5.9±11.3 days). At least one aPL antibody was found in 31 patients (17%).Detection of EE over time after IE diagnosis was more frequent among patients with anti-β2GPI IgM (log-rank P=0.0036) and that of cerebral embolisms, among patients with aCL IgM and anti-β2GPI IgM (log-rank P=0.002 and P<0.0001, respectively).Factors predictive of EE were anti-β2GPI IgM (HR=3.45 (1.47–8.08), P=0.0045), creatinine (2.74 (1.55–4.84), P=0.0005) and vegetation size (2.41 (1.41–4.12), P=0.0014). Those of cerebral embolism were aCL IgM (2.84 (1.22–6.62), P=0.016) and anti-β2GPI IgM (4.77 (1.79–12.74), P=0.0018).ConclusionThe presence of aCL and anti-β2GPI IgM was associated with EE, particularly cerebral ones, and could contribute to assess the embolic risk of IE.