Thrombectomy and distal protection devices

Visible distal embolization is a relatively rare complication during percutaneous coronary interventions but it may occur in 15-20% of angioplasties in saphenous vein grafts (SVG) and in thrombus containing lesions of native coronary arteries, especially in the setting of acute myocardial infarction (AMI). Mechanical thrombectomy devices and distal protection devices have been introduced to reduce the incidence of distal embolisation. Angiojet thrombectomy has shown positive outcomes in thrombus containing lesions when compared with intracoronary thrombolysis but a randomised trial failed to show benefit in the context of AMI. The X-Sizer, Excimer LASER and various simple aspiration thrombectomy catheters show promise in treatment of AMI with improvement shown in surrogate end-points such as resolution of ST-elevation but there have been no randomised trials large enough to demonstrate changes in hard clinical end-points. Distal protection devices have come to be routinely used during SVG treatment and, after the results of the SAFER and FIRE trials; they became a treatment recommendation in the recently issued European Society of Cardiology (ESC) guidelines. For AMI, these devices showed great promise in early single-centre studies which have been offset by the lack of clinical benefit in the multi-centre EMERALD trial. Proximal occlusion devices may further decrease the incidence of distal embolisation, especially in the treatment of totally occluded SVGs or native arteries, by reversing the blood flow and offering protection at a very early stage of the procedure before wire passage. Despite continuous technical improvement and a growing number of miniaturised thrombectomy devices and filters, because of the paucity of controlled large studies, it remains unclear whether these devices will remain limited to niche' applications or will become a regular companion to balloons and stents in mainstream angioplasty procedures.