Experimental Results with the Multi-Linkª Stent in a Porcine Model

OBJECTIVES: The purpose of this study was to assess the delivery characteristics and the vascular response to placement of the Multi-Linka stent in normal porcine coronary arteries. BACKGROUND: The Multi-Link stent is a balloon expandable stainless steel stent with an interconnected corrugated ring structure designed to provide a high degree of compressive resistance while preserving longitudinal flexibility. The placement characteristics and vascular response to this stent in normal porcine coronary arteries has not been characterized. METHODS: We tested the delivery characteristics and vascular response to the Multi-Link stent in 19 normolipemic miniature swine. Quantitative coronary angiography was used to define stent performance characteristics such as stent expansion and recoil. Histologic assessment of the stented arteries was used to evaluate the acute and chronic vascular response to stent placement. RESULTS: Thirty-five of thirty-five stents (100%) were successfully implanted in the left anterior descending (n = 14), left circumflex (n = 8) or right (n = 13) coronary arteries of nineteen swine. The baseline angiographic mean lumen diameter of the stented coronary segment was 3.41 +/- 0.32 mm and increased to 3.53 +/- 0.33 mm (p < 0.001) after stent placement. The balloon inflated stent diameter was 3.61 +/- 0.36 mm with minimal recoil to a final minimal lumen diameter of 3.53 +/- 0.33 mm after implant (p = 0.001). Linear regression analysis revealed that the percent stent recoil had a significant positive correlation with the stent to artery ratio or the degree of stent over-sizing (r = 0.67; p < 0.0001). Angiographic and histologic follow-up at 72 hours (n = 9), 14 days (n = 12) and 56 days (n = 12) demonstrated that all stents were patent without evidence of migration, intraluminal filling defect or side-branch occlusion. On histology, there was rare evidence of stent-induced deep arterial wall injury such as rupture of the internal elastic lamina and medial laceration. There was no significant difference in the mean injury score observed on day 3 (0.23 +/- 0.22), 14 (0.35 +/- 0.28) or 56 (0.36 +/- 0.27) after implant (p = 0.27). On day 3, the mean thrombus thickness overlying the stent wires was 70 +/- 98μ. The mean neointimal area was similar at 14 and 56 days after implant (1.63 +/- 1.25 mm2 versus 1.78 +/- 0.68 mm2, p = 0.54). CONCLUSIONS: The MULTI-LINK stent easily tracked the coronary arteries and deployed reliably in this experimental model. The multiple interconnected ring geometry of the stent provides adequate compressive resistance, longitudinal flexibility and uniform coverage of the arterial wall throughout the length of the endoprothesis. The stent has acceptable blood and tissue biocompatibility in normal porcine coronary arteries. Oversizing this stent (>10 percent) may have a theoretical disadvantage resulting in a proportionally higher degree of stent recoil. The results of clinical trials will determine if the design features of the Multi-Link stent favorably impact on procedural outcome or long-term patency.     

Clinical and Angiographic Results with the Multi-Linkª Coronary Stent System Ñ The West European Stent Trial (WEST)

BACKGROUND: The objectives for the West European Stent Trial (WEST) were to assess the safety and efficacy of the new ACS Multi-Linka coronary stent system with regards to bleedings and vascular complications and incidence of major adverse cardiac events during 12 months follow-up. METHODS AND RESULTS: The balloon-expandable Multi-Link stent is made from a single hypotube and is composed of 316 L stainless steel. In an open, non-randomized, multicenter registry, 102 patients with angina pectoris to be treated with this stent were recruited from 7 European centers. Following stent implantation, patients were given heparin infusion and oral coumadin treatment was maintained for 3 months. Procedural success was achieved in 100 of the 102 patients (98%). One patient had subacute stent thrombosis and 6 patients had major bleeds during the hospital stay. All patients were alive at 12 months and 85% were free of angina pectoris. Nineteen patients (19%) reached a primary clinical endpoint; four patients underwent bypass surgery (two in connection with the stent procedure), four patients suffered an acute myocardial infarction and 11 had a repeat angioplasty of the target vessel. Quantitative angiography showed that the minimum lumen diameter had decreased from 2.66 +/- 0.34 mm after stent deployment to 2.02 +/- 0.58 mm at 6 months and the percent diameter stenosis had increased from 18 +/- 7% to 33 +/- 16%. The in-stent restenosis rate was 12% and appearance of a stenosis in the target vessel outside the stent occurred in an additional 5%. CONCLUSION: The WEST study has demonstrated a high degree of safety and efficacy of the Multi-Link stent with a low incidence of complications and clinical events during follow-up. The results compare favorably with data from other stents.     

To Stent or Not to Stent? Update on Revascularization for Atherosclerotic Renovascular Disease

Renal artery stenosis (RAS) is increasingly encountered in clinical practice. The two most common etiologies are fibromuscular dysplasia (FMD) and atherosclerotic renal artery disease (ARAS), with the latter accounting for the vast majority of cases. Significant RAS activates the renin–angiotensin–aldosterone system and is associated with three major clinical syndromes: ischemic nephropathy, hypertension, and destabilizing cardiac syndromes. Over the past two decades, advancements in diagnostic and interventional techniques have led to improved detection and the widespread use of endovascular renal artery revascularization strategies in the management of ARAS. However, renal artery stenting for ARAS remains controversial. Although several studies have demonstrated some benefit with renal artery revascularization, this has not been to the extent anticipated or predicted. Moreover, these trials have significant flaws in their study design and are hampered with inherent bias which make their interpretation challenging. In this review, we evaluate the existing body of evidence and offer an approach to the management of patients with ARAS in light of the current literature. From the data provided, identification of subgroup of patients, namely, those with a hemodynamically significant RAS in the context of progressive renal insufficiency and/or deteriorating arterial hypertension, seems possible and may derive clinical benefit from ARAS stent revascularization. Appropriate patient selection is therefore the key and more robust studies are required.     

Clinical and angiographic results with the ACS MULTI-LINK DUET™ Coronary Stent System – the DUET Study

BACKGROUND: The DUET Study is a multicenter prospective efficacy and safety evaluation of the ACS MULTI-LINK DUET coronary stainless steel balloon-expandable stent. AIMS: The primary objective was to determine the one-month incidence of MACE (major adverse cardiac events). The secondary objectives were the acute success rate, the restenosis and reocclusion rates (assessed by quantitative coronary angiography (QCA)) at six months and the occurrence of MACE in hospital and at six months. METHODS: Two hundred and ten patients were enrolled between February and June 1998 in 18 European centers. Successful stent placement was achieved in 209 patients. All patients were treated with ticlopidine 500 mg/day for one month and with aspirin &#83 100 mg/day. To allow the investigators to gain familiarity with the stent system, the first one to three patients per center formed a separate lead-in population leaving an intention-to-treat population of 157 patients. population were male (79%); 28% had unstable angina, 69% had stable angina, 44% had had a previous myocardial infarction, 15% had had a previous percutaneous transluminal coronary angioplasty, and 3% had a history of stroke. The target vessel was 38.5% left anterior descending artery, 20.5% left circumflex artery and 41.0% right coronary artery. RESULTS: All but one of the intention-to-treat patients were effectively stented (17 required multiple stents). Six-month angiographic follow-up was available in 90% of the intention-to-treat population. Minimal lumen diameter (MLD) postprocedure was 2.61 &#45 0.33 mm, with a residual diameter stenosis of 16%. Six-month follow-up data showed an MLD of 1.87 &#45 0.56 mm with a residual diameter stenosis of 36%. The binary restenosis rate ( &#83 50% residual stenosis) was 15.6%. Up to one month following the procedure 94.9% of the population was MACE-free, with two subacute occlusions. At six months all patients were alive, of whom 82.8% were MACE-free, and 73% were free of anginal complaints. CONCLUSION: The results observed in the current DUET registry are comparable to The majority of the intention-to-treat data of other balloon-expandable-stent trials, with a low incidence of clinical events at follow-up. (Int J Cardiovasc Intervent 2000; 3: 97-104)