The presence of infection-related antiphospholipid antibodies in infective endocarditis determines a major risk factor for embolic events.
OBJECTIVE
The impact of infection-associated antiphospholipid antibodies (APA) on endothelial cell activation, blood coagulation and fibrinolysis was evaluated in patients with infective endocarditis with and without major embolic events.


BACKGROUND
An embolic event is a common and severe complication of infective endocarditis. Despite the fact that APAs are known to be associated with infectious diseases, their pathogenic role in infective endocarditis has not been clearly defined.


METHODS
The relationship among the occurrence of major embolic events, echocardiographic vegetation size, endothelial cell activation, thrombin generation, fibrinolysis and APA was examined in 91 patients with definite infective endocarditis, including 26 patients with embolic events and 65 control subjects without embolic events.


RESULTS
Overall, 14.3% of patients exhibited elevated APA levels. Embolic events occurred more frequently in patients with elevated levels of APA than in patients without (61.5% vs. 23.1%; p = 0.008). Patients with elevated levels of APA showed higher levels of prothrombin-fragment F1 +2 (p = 0.005), plasminogen-activator inhibitor 1 (p = 0.0002), von Willebrand factor (p = 0.002) and lower levels of activated protein C (p = 0.001) than patients with normal levels of APA. Thrombin generation and endothelial cell activation were both positively correlated with levels of APA. The occurrence of elevated APA levels was frequently associated with structural valve abnormalities (p = 0.01) and vegetations >1.3 cm (p = 0.002).


CONCLUSIONS
Infection-associated elevated APA levels in patients with infective endocarditis are related to endothelial cell activation, thrombin generation and impairment of fibrinolysis. This may contribute to the increased risk for major embolic events in these patients.
Kupferwasser
L I
LI
II. Medical Clinic, Mainz University, Germany. kupferwasser@humc.edu
Hafner
G
G
Mohr-Kahaly
S
S
Erbel
R
R
Meyer
J
J
Darius
H
H
D000328:Adult; D000368:Aged; D017152:Antibodies, Antiphospholipid / Q000032:analysis*; D015415:Biomarkers / Q000097:blood; D002533:Cerebral Angiography; D017548:Echocardiography, Transesophageal; D004697:Endocarditis, Bacterial / Q000150:complications / Q000175:diagnosis / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005342:Fibrinolysis; D005500:Follow-Up Studies; D006351:Heart Valves / Q000000981:diagnostic imaging; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000175:diagnosis / Q000209:etiology / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D011379:Prognosis; D011486:Protein C / Q000378:metabolism; D012189:Retrospective Studies; D012307:Risk Factors; D013917:Thrombin / Q000378:metabolism; D014057:Tomography, X-Ray Computed; D018608:Ultrasonography, Doppler
D017152:Antibodies, Antiphospholipid; D015415:Biomarkers; D017395:Plasminogen Activator Inhibitor 1; D011486:Protein C; D013917:Thrombin