Clinical experience with the Wiktor stent in native coronary arteries and coronary bypass grafts.

Abstract

Objectives-To evaluate the results of implantation of Wiktor tantalum wire coronary stents in stenosed or occluded coronary vessels or in saphenous vein bypass grafts. Design-A retrospective analysis of clinical and angiographic data from patients treated with tantalum wire stents implanted by one operator at two centres.Patiens-52 patients undergoing conventional balloon angioplasty had 67 lesions treated by stents after acute or threatened closure of the target vessel, or because the lesions concerned were considered to be at particularly high risk of becoming restenosed, or because the result of primary angioplasty was inadequate.Results-65 of the 67 lesions were successfully stented although in two cases the first attempt failed and a second stent was then implanted successfully. There were no cases of stent occlusion and no myocardial infarctions in hospital or in the follow up period of 1-20 months. Eight patients had haemorrhagic complications that were minor in 4. One patient later had coronary bypass surgery after failure to stent a lesion. Angiographi_ follow up at a mean of 6 months after stenting showed restenosis associated with 4 of 47 stents studied. All patients with chest pain had-had repeat angiography, and 84% of those without symptoms also agreed to reinvestigation after about 6 months.Conclusions-The Wiktor tantalum wire stent is an effective means of treating acute complications during angioplasty and seems to offer hope of a significant reduction in the rate of late restenosis in both native coronary vessels and saphenous vein bypass grafts. A prospective comparison of balloon angioplasty and stenting is needed. (Br HeartJ 1994;72:288-293) Transluminal coronary angioplasty is now established as a routine treatment for patients with suitable coronary obstructive lesions and appropriate clinical indications for intervention. The technique has also been used successfully in patients with stenosis or recent occlusion in coronary bypass grafts. Several problems remain to be solved, however, including the optimal ways of managing acute complications of angioplasty such as actual or impending occlusion, dissection, or inadequate result of dilatation. A high rate of restenosis is also a common feature in follow up angiographic studies and this seems to be particularly troublesome in bypass grafts. Attempts to deal with these problems have included the use of intracoronary stents of which a number of different designs are available. Initial experience with the Wiktor tantalum wire stent confirmed its value as a bail out manoeuvre for acute angioplasty complications,' 2 but its use was associated with subacute stent occlusion and a rate of restenosis comparable with that seen after balloon angioplasty. We report here our experience of the use of Wiktor stents (Medtronic) in a series of patients treated by a single operator with a standardised protocol for treatment before, during, and after the implantation procedure.

The evolution of cardiovascular stent materials and surfaces in response to clinical drivers: A review

“…This device has been shown to have good MR imaging behaviour; however, this approach has not been used for coronary stents, most likely because the material would be too radio-opaque -even for X-ray fluoroscopy. The tantalum peripheral devices described earlier [40,41] also had reduced susceptibility artefact but this was purely incidental. While these stents became obsolete for design reasons, use of pure tantalum did not successfully carry through to newer coronary designs, due to lack of mechanical property optimization and also as the high radio-opacity would again be unsuitable for smaller stent sizes.…”

“…Such material developments have indeed been fewer than the efforts to increase strength and radio-opacity, but this is understandable given the more tentative nature of any potential benefit and the investment already going into higher-strength and radio-opacity needs. Tantalum was explored early during stent development and was used in both the coronary Wiktor stent (Medtronic Inc., Minneapolis, MN) [40] and the peripheral Strecker stent (Boston Scientific Corp., Natick, MA) [41]. These were helical wound wire and knitted wire structures, respectively.…”

Angiographic and clinical one-year follow-up of the Cordis tantalum coil stent in a multicenter international study demonstrating improved restenosis rates when compared to pooled PTCA and BENESTENT-I data: The European Antiplatelet Stent Investigation (EASI)

“…The Cordis stent is essentially a coil stent mechanically without longitudinal integrity when compared to stents made to the slottedtube design. Previous data have implied that early and late outcomes with coil stents were not as good as those for slotted-tube configurations [21][22][23][24][25][26][27][28]. Both the Gianturco-Rubin stent and the Wiktor stents have been associated with a higher acute closure rate and restenosis rate.…”

Development of a new niobium-based alloy for vascular stent applications

“…Tantalum has been used in the past with some degree of success for both the Wiktor coronary stent (Vaishnav et al, 1994) and the Strecker peripheral stent (Long et al, 1995). However, the possibility of Ta alloy development was ruled out as it was considered that the high density of the material would result in excessive radiopacity when imaged Having selected niobium as the platform for alloy development, some commercial compositions were initially assessed.…”