Treatment of Post-Stenotic Saphenous Vein Graft Aneurysm:
Special Considerations with the Polytetrafluoroethylene-
Covered Ste

The treatment of coronary or saphenous vein graft (SVG) aneurysms has traditionally been surgical.^1,2 With the advent of percutaneous coronary techniques, less invasive approaches are possible in the management of this rare but serious condition.³ Acute coronary syndrome, myocardial infarction, graft rupture and fistula formation have all been reported as a result of SVG aneurysms.^4–6 Stenting of coronary and saphenous vein graft aneurysms have been reported with vein-covered stents.^7,8 The use of polytetrafluoroethylene (PTFE)-covered stents has been reported in the treatment of coronary arterial aneurysms;⁹ reported use of this device in SVG aneurysms has been rare, if at all, in the literature. Our review showed no direct reported cases of PTFE-covered stents in SVG aneurysms. We present a case demonstrating the application of PTFE-covered stent in the treatment of a challenging SVG anatomy involving a significant ostial lesion followed by a large, saccular post-stenotic aneurysm. The use of this relatively stiff and bulky device in potentially difficult SVG anatomy deserves special considerations and technical strategy. Case report. A 69-year-old male who underwent a coronary bypass graft surgery (CABG) 20 years ago and received a second CABG approximately 10 years ago, presented with recurrent angina. The anatomy for the re-do CABG was a SVG to the left anterior descending artery (LAD) and a sequential SVG to the diagonal branch, obtuse marginal branch and distal (RCA). A stress nuclear examination showed the presence of a new inferolateral reversible defect. A diagnostic catheterization showed significant left main disease, occluded LAD and RCA and occluded obtuse marginal branch of the left circumflex artery. The SVG to the LAD was patent, however, the sequential SVG showed a 95% ostial lesion followed by a saccular post-stenotic aneurysm which measured 12 x 13 mm2 (Figure 1). The decision was made to treat the culprit lesion via the percutaneous interventional approach. An 8 Fr Judkins Right guiding catheter and a 0.014 inch BMW (Guidant, Temecula, Calif.) were chosen for support and device delivery. The lesion was pre-treated with a 2.5 x 10 mm followed by a 4.0 x 10 mm cutting balloon (Boston Scientific/Scimed, Maple Grove, Minn.). Repeat angiography showed enlarged entrance to the SVG and aneurysm without dissection, perforation or rupture (Figure 2). The ostial SVG lesion, along with the post-stenotic aneurysmal segment, were stented with a 16 mm PTFE-covered stent (Jostent, JOMED GmbH, Germany), which had been free-mounted onto a 4.0 x 20 mm Maverick 2 balloon (Boston Scientific/Scimed). After stent deployment, the distal end of the covered stent was seen to have dislocated into the aneurysm proper and the outlet of the stent was not in direct alignment with the rest of the SVG (Figure 3). In order to realign the PTFE-covered stent, further stent coverage extending beyond the distal margin of the first stent was clearly necessary. Another free-mounted PTFE-covered stent was deemed risky due to its relative rigidity, bulk and potential for dislodgement. Decision was made to place a conventional, low-profile, pre-mounted bare metal stent, a 4.5 x 18 mm Bx Velocity (Cordis, Miami Lakes, Florida) (drug-eluting stents were not yet available). The choice for a longer stent was to secure mid-segment axial strength where there was no mechanical support from the adjacent vascular wall (see discussion). Post-dilation was performed using a 5.0 x 20 mm Maxxum balloon (Boston Scientific/Scimed) with an excellent final angiographic outcome and minimal contrast extravasation at the distal end of the aneurysm (Figure 4). Discussion. SVG aneurysms can be large.^2,5 Appropriate use of the PTFE-covered stents in SVG intervention must take into account the overall size of the aneurysm, vessel tortuosity, factors influencing restenosis rate and the device delivery. The free-mounted Jostent (JOMED) represents a relatively rigid and bulky device for delivery with the potential for stent dislodgement, especially in challenging vessel anatomy. The case presented here demonstrated a difficult SVG anatomy with a significant ostial lesion followed by an almost spherical post-stenotic aneurysmal dilatation. Technical and anatomic considerations include the lack of an adequate proximal “anchor” for stent stability, the need to cover the entire length of the aneurysm, the potential for stent-edge “hang up” at both ends of the aneurysm during delivery, and the potential for stent dislodgement. After the initial Jostent deployment, the loss of a distal-edge “anchor,” which may have been caused by movements during stent deployment, represented an interventional dilemma. The outflow of the Jostent clearly had to be realigned with the entrance to the SVG. Mechanical realignment of the Jostent with further stenting was deemed necessary. A pre-mounted stent, rather than another free-mounted Jostent, was chosen to secure deliverability and success in the salvage effort, even though a gap in covering the entire aneurysm at the distal edge may occur. The choice of length of the pre-mounted stent was another major technical consideration. The immediate thought was to use a short stent for deliverability and less metal. The lack of adjacent vascular wall support within the aneurysm, however, would increase the likelihood of “buckling” in the conjoining mid-segment (Figure 5). To ensure mid-segment integrity or axial strength of the entire implanted stent structure, a longer stent became the logical choice. The addition of a second PTFE-stent to seal the distal leak was not necessary due to the eventual thrombosis of the aneurysm. Although the restenosis rate of the PTFE-covered stents appears similar to bare stainless steel stents in SVG, it is associated with a higher incidence of non-fatal myocardial infarction.¹⁰ The use of PTFE-covered stents in SVGs should be judicious. In the treatment of SVG aneurysms, the PTFE-covered stent is a promising tool. As demonstrated by this case, the technical and anatomic challenges deserve continued interest and focus.

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