Vein Graft Intervention: Progress and Continued Challenges

Background: Saphenous vein grafts (SVG) remain the most common conduit used in coronary artery bypass surgery. Within 10 years after the operation, most SVG develop significant disease. Percutaneous coronary intervention (PCI) of SVG is associated with a high risk of distal embolization, no-reflow, periprocedural myocardial infarction, and late restenosis. Role of Stents. Coronary stenting has had a preeminent role in the treatment of SVG disease since the SAVED trial. Compared to balloon angioplasty, bare metal stents resulted in superior angiographic and clinical outcomes. The role of drug-eluting stents (DES) remained uncertain initially due to mixed results of early small trials. The superiority of DES was established by the larger ISAR-CABG trial which showed that DES were associated with fewer cardiac events at 1 year. Despite the incremental benefit of DES, most patients after SVG PCI will have a major cardiac event within 5 years. Distal Embolization. SVG intervention is fraught with a high risk of ischemic complications due to distal embolization. In the SAFER trial, use of a distal protection device (DPD) was associated with a significant reduction in early cardiac events. However, despite their proven clinical benefit and guideline class I recommendation, DPD are used in less than 25% of SVG PCI. No-Reflow. Development of no-reflow during PCI is a powerful risk factor for myocardial infarction and death. DPD have reduced but not eliminated no-reflow, a complex phenomenon involving both debris embolization and microvascular spasm. Vasodilating drugs effective in treating no-reflow include calcium channel blockers, adenosine, and nitroprusside. In the largest treatment series of patients with no-reflow during PCI, intracoronary nicardipine was successful in restoring normal flow in >98% of cases. It has been suggested that pretreatment with intracoronary vasodilators such as nicardipine may reduce the incidence of no-reflow. We utilize the synergistic effect of combining prophylactic intracoronary nicardipine and distal protection filters in vein graft PCI to further reduce periprocedural ischemic events.
Conclusion: SVG intervention continues to evolve due to advances in procedural techniques and stent technology. Further work is needed to improve longer term clinical outcomes following vein graft PCI.