Plaque composition by intravascular ultrasound and distal embolization after percutaneous coronary intervention

Distal embolization after percutaneous coronary intervention occurs in 15% to 70% of patients, depending on the sensitivity of the diagnostic modality used, and is associated with a poor prognosis after elective and primary percutaneous coronary intervention. It has been hypothesized that imaging of the plaque composition can identify coronary artery lesions that are predisposed to causing distal embolization. This review report aims to summarize all currently available published data on the use of assessment of atherosclerotic plaque composition by virtual histology intravascular ultrasound (VH-IVUS) to predict the occurrence of distal embolization. A systematic review of the literature was performed. We searched Medline, ISI Web of Knowledge, and the Cochrane Library from January 2002 until March 2011. When a study was found to be relevant, the manuscript was obtained and reviewed. A total of 11 studies were identified investigating the relationship between plaque composition assessed by VH-IVUS and distal embolization. Although all studies used the same equipment to perform and analyze VH-IVUS, there was considerable heterogeneity in patient characteristics, outcome definitions, and reporting of VH-IVUS findings. Nevertheless, the necrotic core plaque component-either by itself or as a constituent of a VH thin cap fibroatheroma-was associated with distal embolization in all but 2 of the 11 reviewed studies. Therefore, identification of lesions with large amounts of necrotic core on VH-IVUS could identify lesions that might benefit from the selective use of embolic protection devices.