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Embolic protection devices
Philip A Morales1, Richard R Heuser
1Phoenix Heart Center, St. Luke's Medical Center, 525 North 18th Street, Suite 504, Phoenix, AZ 85006, USA.
Insights
Saphenous vein graft failure is common after bypass surgery. Distal protection devices mitigate risks during interventions by preventing plaque embolization, improving outcomes.
Area of Science:
- Cardiovascular Surgery
- Interventional Cardiology
- Biomedical Engineering
Background:
- Saphenous vein grafts (SVGs) frequently develop atheromatous disease, leading to graft failure within 10 years.
- Repeat coronary artery bypass surgery (CABG) carries higher risks than the initial procedure.
- Catheter-based interventions on SVGs are complicated by distal embolization of plaque, causing "no-reflow" and increasing adverse events.
Purpose of the Study:
- To discuss current distal protection devices used during percutaneous interventions on saphenous vein grafts.
- To highlight the mechanisms of SVG failure and the role of distal embolization.
- To review the technology and application of devices designed to protect the distal microcirculation.
Main Methods:
- Review of current literature and available technologies for distal protection during SVG interventions.
- Description of two main types of distal protection devices: balloon occlusive systems and filter-based systems.
- Explanation of the mechanism of action for each device type in preventing distal embolization.
Main Results:
- Distal protection devices aim to prevent atheromatous and thrombotic material from reaching the distal microcirculation.
- Balloon occlusive systems temporarily block the vessel and aspirate debris.
- Filter-based systems use filters to trap debris while maintaining some blood flow, with subsequent retrieval of the trapped material.
Conclusions:
- Distal protection devices are crucial for minimizing complications during saphenous vein graft interventions.
- These devices help prevent myocardial infarction and late mortality associated with distal embolization.
- The choice between occlusive and filter-based systems depends on procedural needs and specific clinical scenarios.
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.