Prosthetic valve thrombosis (PVT) is serious complication of valvular replacement surgery, and increased levels of anticardiolipin antibodies (aCL) are associated with thrombosis. The aim of this study was to evaluate the role of aCL in the development of PVT.

We studied the aCL IgM and IgG levels in 114 patients with PVT and 80 healthy patients with prosthetic valves without PVT or a history of thrombosis. All patients underwent detailed transthoracic, transesophageal echocardiographic and clinical examinations. Blood samples were obtained after transesophageal echocardiography. Tests were repeated 12 weeks apart in patients with aCL IgM or IgG positivity.

The mean age, sex, presence of atrial fibrillation and cardiovascular risk factors, elapsed time after surgery, and prosthetic valve type and location were similar between patients with PVT and those without. Ineffective anticoagulation was significantly higher among patients with PVT (p < 0.001). The aCL IgM values were significantly higher and positive (> 40 MPL) in the PVT group compared with the control group (10.58 ± 15.90 MPL to 3.70 ± 2.30 MPL, p < 0.001; 7.0 to 0 %, p = 0.016, respectively). The aCL IgG values were significantly higher and positive (> 40 GPL) in the PVT group compared with the control group (12.04 ± 17.58 GPL to 3.83 ± 2.56 GPL, p < 0.001 and 7.9 to 0 %, p = 0.01, respectively). According to international consensus documents, 16 patients had antiphospholipid syndrome. Ineffective anticoagulation and aCL IgM and IgG positivity were independent predictors of PVT in logistic regression analysis (multivariate r²= 0.648; p < 0.001, OR= 21.405, 95 %CI= 8.201–55.872; p = 0.008, OR= 1.322, %95CI= 1.076–1.626; p = 0.005, OR= 1.288, 95 %CI= 1.079–1.538).

Since the presence of aCL IgM and IgG positivity may cause a tendency toward PVT, these values should be examined in all patients with PVT.