Letters to the Editor

Percutaneous implantation of autologous vein graft stent for treatment of coronary artery disease

In clinical practice, the operator must decide which stent is most appropriate for the patient. This article focuses on the features of stent design that make a specific stent more or less suitable for a particular type of lesion or anatomy: the “average” coronary lesion, the lesion situated on a curve, the ostial lesion, the bifurcational lesion, the lesion located at the left main stem, the calcified lesion, the chronic total occlusion, the small vessel, the saphenous vein graft, acute or threatened vessel closure, and special situations such as coronary aneurysms and perforations.

Background Previous experimental studies with a new covered stent, the autologous venous graft-covered stent (AVGCS), have shown favorable results. The aim of this study was to evaluate the feasibility and safety of this new technique in human coronary arteries and to compare the long-term outcome with uncovered stents.

Methods and Results A venous graft was removed from an upper limb. A conventional stent then was covered by the venous graft. Fifty-eight AVGCS were implanted in 56 patients, including 16 patients with acute coronary syndromes (ACS). Additionally, in 114 patients, 138 uncovered stents were implanted, serving as a control group, including 38 patients with ACS. The procedure was successful in all patients. Stent thrombosis was observed in 3 patients in the control group and in 1 patient with an AVGCS. There was a trend for the minimal luminal diameter to be greater in the AVGCS group at follow-up (P = .07), and statistical significance was observed in patients with ACS (P < .01). The target vessel revascularization and the restenosis rates were similar between the 2 groups. In patients with ACS, the restenosis rate was less (P < .04) and there was a trend for target vessel revascularization to be less in covered stents (P = .09). The event-free survival rate at 4 years was 85% in the AVGCS group versus 81 % in the control group (P = not significant); in ACS it was 94% versus 78%, respectively (P = not significant). Stents covered by thicker venous grafts were associated with improved clinical outcome.

Conclusions Stents covered by autologous venous grafts may be safely prepared without complications. This technique may prove to be a useful means, especially in patients with ACS.

Objectives. A new type of coated stent, consisting of a conventional stent covered by an autologous vein graft, was developed at our institution.

Background. Coated stents are under investigation to address stenting limitations. However, experimental implantation of coated stents covered by autologous tissue has not been reported.

Methods. An autologous vein graft was removed and carefully prepared. Subsequently, a Palmaz stent was covered by the vein graft both internally and externally. Twenty-seven stents were implanted in the normal iliac arteries of 27 pigs weighing 18 to 33 kg. In 15 of the pigs, 15 noncoated Palmaz stents were implanted in the contralateral artery; these animals served as the control group. The animals were followed up angiographically for a period ranging from 7 days to 6 months. At the time of death, the stented segments were removed, and histomorphometric analysis was performed.

Results. Autologous vein graft-coated stent preparation and implantation was feasible and uncomplicated. In both stents, angiographic follow-up revealed the absence of thrombosis, except for two cases of subacute thrombosis in the control group. The thickness of the intimal layer was greater in the coated stents and seems to be due to the existence of the internal vein layer ([mean ± SD] 0.57 ± 0.12 vs. 0.27 ± 0.13 mm, p = 0.001). The arterial media of the coated stent segments was thinner than that in the control group (0.14 ± 0.03 vs. 0.18 ± 0.01 mm, p = 0.02).

Conclusions. The autologous vein graft-coated stent seems to be nonthrombogenic, and only minimal hyperplasia was observed in the pigs. Further studies are needed to explore the efficacy of this technique in humans.