The carotid atherosclerotic plaque and microembolisation during carotid stenting.
Microembolisation is an important issue in carotid artery stenting. During different phases in the stenting process, numerous emboli are dislodged from the atherosclerotic plaque. Embolisation can be measured as microembolic signals detected by transcranial Doppler (TCD) monitoring during the procedure or as new ischemic areas determined by magnetic resonance imaging. This article gives an overview of the principles of emboli detection methods, their clinical relevance, and risk factors associated with microembolisation. In addition, protection devices are discussed in relation to embolisation. Although they potentially protect the brain, particularly filter devices increase the amount of TCD-detected cerebral microemboli. Special attention is paid to the carotid artery plaque, which is subject to ongoing research that may yield important implications for clinical practice in the near future. Evidence is accumulating that unstable, vulnerable plaques are associated with increased microembolisation during carotid interventions. This knowledge of the vulnerable plaque can be translated to the clinical setting by plaque imaging. A first approach has been made by duplex imaging of carotid plaque morphology. More advanced methods such as molecular magnetic resonance imaging and optical coherence tomography could aid in optimal treatment selection based on plaque characteristics thus reducing microembolisation and associated cerebral adverse events.