Cerebral microembolization in patients with prosthetic valve and anticoagulation assessment using transcranial Doppler ultrasonography

Abstract

Background Transcranial Doppler detection of microemboli is widely described, and thromboembolism is a major cause of morbidity in patients with prosthetic heart valves. They require lifelong anticoagulation to minimize thrombotic complications. This study was undertaken to assess the clinical relevance of microembolic signals (MESs) and their relation to anticoagulation.Patients and methods Thirty patients with single mitral mechanical prosthetic valve were included. All of them were selected with low intensity of international normalization ratio (INR). After 2-week interval, INR intensities were stabilized to the recommended levels. Transcranial Doppler monitoring for MES detection was done to the same patients, before and after the stabilization of INR intensities.Results Microemboli were detected in 86.7% of patients before and after the INR level adjustment, with mean number of 57.63±13.12 before adjust. The numbers were significantly lowered after the adjustment of INR, as the emboli number became 24.1±9.12.Conclusion Compared with previously thought findings, the study results were different, as there was a significant effect of the anticoagulation on the number of MESs detected in patients with mechanical valve replacement, but without effect in MES incidence, denoting that, there were a variety of MESs rather than thrombotic. Further assessment by MES differentiation to define solid ones will be indicated.