Implantation of the Wallstent for diffuse lesions and multiple lesions in coronary arteries and vein grafts -Milan Experience-

Background: Treating a long lesion or multiple lesions with a single Wallstent seems to be an attractive alternative to multiple stenting with shorter stents. Patients and Methods: We treated 68 patients (69 vessels with 75 lesions) with diffuse lesions in native coronary arteries and vein grafts with intravascular ultrasound-guided Wallstent implantation. Both coronary and peripheral versions of the Wallstent were used in this study. All patients were followed with only aspirin and ticlopidine and no oral anticoagulants after the procedure. Results: Average balloon pressure during stent optimization was 16.5 atmospheres. Intravascular ultrasound was performed in 85% of the patients to confirm the optimal stent expansion. The stents could be implanted successfully in 61 patients (90% success rate). There were 2 cases of emergent bypass surgery associated with delivery failure, and 1 subacute stent thrombosis occurred 4 days after implantation. The follow-up angiography revealed that the restenosis rates were 38.9% in the total cohort, 40.0% with the coronary version, and 37.5% with the peripheral version. The immediate results after Wallstent implantation were excellent both by angiography and intravascular ultrasound because of its superior scaffolding property and radial force. However the restenosis rate was somewhat higher than we had expected. Although there is one hypothesis that radically oversized Wallstents may cause disproportionate vessel stretch and lead to profound tissue proliferation, no relationship was seen between the late lumen loss and the degree of oversizing. Conclusion: The Wallstent implantation in a diffuse lesion or a long total lesion is feasible, however restenosis remains as a critical problem even with this method.