Embolic protection devices

Abstract

The limiting factor in coronary artery bypass surgery is the relatively rapid progression of atheromatous disease in the saphenous vein grafts. Greater than one-half of these vein grafts will fail by 10 years, and the risks associated with repeat coronary artery bypass surgery are significantly greater than that of the initial surgery. Yet, catheter-based interventional treatment of saphenous vein grafts is hindered by distal embolization of friable lipidrich plaque. This is one mechanism responsible for reduced antegrade flow (i.e., "no-reflow" phenomenon), including spasm of the distal microcirculation and platelet clumping. This complication increases the risk of a major adverse clinical event (i.e., myocardial infarction or late mortality). Distal protection devices are designed to provide protection of the distal microcirculation during percutaneous intervention. One device type is a balloon occlusive system that temporarily occludes the distal vessel during the intervention followed by the aspiration of liberated atheromatous and thrombotic material before it reaches the arteriolar and capillary bed. The other device type is a nonocclusive, filter-based system that preserves coronary blood flow through tiny pores, as low as 100 microns. Atheromatous and thrombotic material is trapped in the filter-based systems and then removed with the retrieval of the device through a retrieval catheter. This article discusses the current distal protective devices.