Clinical relevance of the detection of microembolic signals using transcranial Doppler sonography

Detection of microembolic signals (MES) has been described in several patient groups. A potential clinical relevance of this technique has been established (1) during the first hours following carotid endarterectomy and (2) for patients with asymptomatic ICA stenosis or various autoimmune disorders. Intraoperative monitoring in patients undergoing cardiac or carotid surgery can be used to improve the surgical technique but provides no prognostic information for individual patients. Microembolic signals in patients with prosthetic heart valves cannot be used as markers for stroke risk;their potential significance as markers for neuropsychological deficits remains unclear. Recent reports suggest that MES can be used as surrogate markers for assessing the efficacy of antiplatelet agents. The fact that automated MES detection is not feasible greatly reduces the technique's applicability. On the whole, MES detection - with the exception of the patient groups listed above - provides pathophysiological rather than clinically relevant information.