Chapter 36: Intervention in Venous and Arterial Grafts

HISTORICAL DEVELOPMENT

The surgeon’s use of saphenous veins and a variety of arterial conduits to bypass obstructive coronary atherosclerotic disease preceded percutaneous revascularization by about a decade. In that relatively short period of time, the inferiority of venous compared to arterial grafts and the potential for atheroembolization with vein graft manipulation at surgery had become apparent. When Andreas Gruentzig reported the first 50 patients treated with percutaneous coronary angioplasty in 1979, 5 had undergone saphenous vein graft (SVG) dilatation, and 3 (60%) had developed restenosis, leading him to surmise “the different kind of disease may explain the high incidence of recurrence in graft stenosis” and to question the wisdom of percutaneous SVG intervention.¹ In the more than 35 years since that observation, interventional cardiologists have struggled with the indications for SVG intervention because of higher acute complications, more restenosis than was observed in native coronary arteries and arterial grafts, rapid disease progression in nontarget sites, and high late cardiac event rates. By 1983, outcomes of SVG intervention had been more completely characterized, and the first left internal mammary artery intervention had been reported.² In a subsequent summary of several thousand reported cases of balloon angioplasty in SVGs, procedural mortality was less than 1%, Q-wave infarction occurred in less than 2% of cases, and emergency surgery was required in 0.3% to 4% of cases.³ A gradient was observed in SVG restenosis rates, with very high rates approaching 70% at proximal anastomoses and progressively lower rates in more distal locations (see discussion mid-SVG and distal anastomosis). Subsequent maturation of graft percutaneous coronary intervention (PCI) occurred with improved understanding of patient and lesion selection, application of stents and embolic protection strategies, prediction and prevention of complications, and use of intravascular imaging as discussed below. Unfortunately, the goal of procedural and long-term safety and optimal durability of graft PCI has been illusive following treatment with SVGs.

BARE METAL STENTS IN SAPHENOUS VEIN GRAFTS

Use of stents in SVG intervention was supported by the report in 1995 of the Palmaz-Schatz multicenter registry experience in over 500 patients with the following favorable outcomes: procedural success, 97%; stent thrombosis, 1.4%; in-hospital mortality, 1.7%; urgent surgery, 0.9%; and restenosis in 18% of de novo lesions and 46% of restenotic lesions.⁴ In the Saphenous Vein De Novo (SAVED) trial, 220 patients with SVG stenosis of at least 50% and angina or objective evidence of ischemia were randomized to deployment of a Palmaz-Schatz stent or balloon angioplasty.⁵ Patients with lesion lengths requiring more than 2 stents, myocardial infarction within 7 days, or graft thrombus were excluded. Patients who underwent stent implantation had a higher procedural efficacy, defined as a reduction in stenosis to less than 50% of the vessel diameter with the assigned therapy (92% vs 69%; P < .001). Patients assigned to stents had a larger increase in lumen diameter immediately (1.92 vs 1.21 mm; P < .001) ...