Incidence of intracardiac thrombus and thromboembolism in the first three months after bioprosthetic valve implantation

OBJECTIVE: To assess the incidence of intracardiac thrombus and thromboembolism in the first 3 months after bioprosthetic valve replacement and to identify the risk factors for thrombus formation. METHODS: The study comprised 184 patients, aged between 15 and 75 years, who underwent bioprosthetic valve implantation. Transthoracic and transesophageal (TEE) echocardiographies were performed in the in-hospital phase (mean, 8.4±3 days) and after 3 months (mean, 97.4±21.7 days). RESULTS: The incidence of thrombus was significantly greater in patients with a prosthesis in the mitral or mitroaortic position (21.0%) than in those with a prosthesis in the aortic position (2.8%), P<0.001. The multiple logistic regression identified the prosthesis in the mitral or mitroaortic position as the only independent variable for thrombus formation. On the 3-month follow-up, TEE showed a thrombus in 35 (20.7%) of the 169 patients on echocardiographic assessment, 31.7% in mitral patients and 3.1% in aortic patients, P<0.001. In the third month, the multiple logistic regression also identified the prosthesis in the mitral or mitroaortic position as the only independent variable for thrombus formation. During the 3-month follow-up, 3 (1.6%) patients died and 8 (4.3%) experienced embolic phenomena, all in the cerebral territory. CONCLUSION: The incidence of thrombi in the first 3 months after bioprosthetic valve implantation was 14.1% in the first 10 days and 20.7% in 3 months. A prosthesis in the mitral or mitroaortic position was identified as a risk factor for thrombus formation. The incidence of embolic phenomena clinically diagnosed was lower than the proportion of atrial thrombi documented on echocardiography.