The role of distal myocardial protection devices during percutaneous coronary interventions.

The success of intervention and clinical outcome is markedly reduced in patients who sustain distal embolization during percutaneous coronary intervention (PCI). Such embolization occurs in up to 15% of patients with acute myocardial infarction (AMI) undergoing PCI, and angiographic indicators of embolization are highly predictive of clinical and functional outcome. Saphenous vein graft (SVG) interventions carry a 20% risk of major adverse cardiac events (MACE), predominantly AMI, and significant risk of no-reflow. There are four types of embolic protection: distal occlusion/aspiration systems, filters, proximal occlusion/aspiration devices, and thrombectomy catheters. There seem to be no data to suggest that routine use of any embolic protection system is beneficial in patients with ST-elevation myocardial infarction (STEMI) undergoing PCI. The message from both the EMERALD and PROMISE trials is that embolic protection does not improve perfusion in the setting of AMI. Although pretreatment with thrombus aspiration before PCI improves angiographic reperfusion rates compared with standard PCI, enzymatic release and early clinical outcomes are not improved. Although the clinical implications of routine thrombus aspiration have yet to be established, selective use may be justified in patients with the highest thrombus burden. In addition, it should be considered in those with acute stent thrombosis and elective use of filter-based protection considered in very high risk vessel PCI (eg, last remaining conduit). There is no easy way to anticipate which SVG intervention will result in embolization. In SVG intervention, both balloon occlusion/aspiration and filter-based distal protection devices have significantly reduced the incidence of 30-day MACE, driven by AMI and should, I believe, be used routinely. Risk of complications is low with all the established devices. The profile and deliverability are continuing to improve with newer devices. Cost-effectiveness of selective use in high-risk graft cases has only recently been demonstrated.