Morphologic change in coronary artery stenosis with the Medtronic Wiktor stent: initial results from the core laboratory for quantitative angiography.

The purpose of this study was to assess the early changes in stenosis geometry after implantation of the Medtronic Wiktor stent in human coronary arteries. Morphologic changes were evaluated by quantitative coronary angiography using automated edge detection. The hemodynamic significance of the morphologic changes were assessed by the calculation of the theoretical pressure drop across the dilated and stented stenosis derived from the Poiseuile and turbulent resistances assuming a coronary blood flow of either 0.5, 1, or 3 ml/sec. Fifty patients were studied before and immediately after stent implantation. The stented coronary artery was the left anterior descending artery in 26 patients, the circumflex artery in eight patients, and the right coronary artery in 16 patients. Stent implantation resulted in an additional increase in the minimal luminal cross-sectional area and minimal luminal diameter of the dilated vessel without changing the curvature of the stenosis. Furthermore, there was a significant reduction of the "plaque area." This was associated with a normalization of the calculated resistances to flow and pressure drop across the stenosis. To a minimal extent, recoil (0.1 +/- 0.36 mm) was observed after stent implantation.     

Angiographic and three-dimensional intravascular ultrasound analysis of combined intracoronary beta radiation and self-expanding stent implantation in human coronary arteries

This study tested the combination of vascular brachytherapy (VBT) and self-expanding Wallstent implantation in coronary lesions of patients at high risk for restenosis as assessed angiographically by quantitative coronary analysis and by 3-dimensional intravascular ultrasound analysis. Twenty-nine "de novo" lesions were managed with a self-expanding stent alone (n = 19) or with a self-expanding stent after beta-VBT (n = 10) in 27 patients who had been identified by high levels of plasma angiotensin-converting enzyme as being prone to myointimal growth after stent implantation. At 6 months, the increase in stent strut diameter was similar in the 2 groups by quantitative coronary analysis and 3-dimensional intravascular ultrasound (Delta mean stent strut diameter -0.33 +/- 0.3 vs -0.40 +/- 0.3 mm, p = 0.5; Delta stent area -11.8 +/- 6.1 vs -12.0 +/- 6.1 mm(2), p = 0.9; Delta stent volume -96.9 +/- 112 vs -83.5 +/- 73 mm(3), p = 0.7; for groups treated with VBT and self-expanding stents and only self-expanding stents, respectively). In-stent neointimal proliferation was decreased in the group treated with VBT and self-expanding stents (minimal luminal diameter 2.5 +/- 0.8 vs 1.88 +/- 0.8 mm, p = 0.04) by quantitative coronary analysis (minimal luminal area 6.7 +/- 2.5 vs 4.1 +/- 1.9 mm(2), p = 0.01), by intravascular ultrasound, and proliferation volume (84.6 +/- 66.4 vs 159.2 +/- 103.5 mm(3), p = 0.05) by 3-dimensional intravascular ultrasound. Positive vessel and luminal remodelings were observed in 50% of the group treated with VBT and self-expanding stents and in 11% of the group treated only with self-expanding stents (p = 0.02). The combined use of VBT and self-expanding stents is a novel approach that enlarges vascular lumen by preventing vessel constriction and neointimal proliferation. The feasibility and good results of this experimental approach suggest that the simultaneous use of these 2 technologies may be an interesting alternative for difficult vascular districts with high restenosis rates, such as peripheral circulation in the lower limbs.     

Wiktor stent implantation in patients with restenosis following balloon angioplasty of a native coronary artery.

Intracoronary stenting has been introduced as an adjunct to balloon angioplasty aimed at overcoming its limitations, namely acute vessel closure and late restenosis. This study reports the first experience with the Wiktor stent implanted in the first 50 consecutive patients. All patients had restenosis of a native coronary artery lesion after prior balloon angioplasty. The target coronary artery was the left anterior descending artery in 26 patients, the circumflex artery in 7 patients and the right coronary artery in 17 patients. The implantation success rate was 98% (49 of 50 patients). There were no procedural deaths. Acute or subacute thrombotic stent occlusion occurred in 5 patients (10%). All 5 patients sustained a nonfatal acute myocardial infarction. Four of these patients underwent recanalization by means of balloon angioplasty; the remaining patient was referred for bypass surgery. A major bleeding complication occurred in 11 patients (22%): groin bleeding necessitating blood transfusion in 6, gastrointestinal bleeding in 3 and hematuria in 2. Repeat angiography was performed at a mean of 5.6 +/- 1.1 months in all but 1 patient undergoing implantation. Restenosis, defined by a reduction of greater than or equal to 0.72 mm in the minimal luminal diameter or a change in diameter stenosis from less than to greater than or equal to 50%, occurred in 20 (45%) and 13 (29%) patients, respectively. In this first experience, the easiness and high technical success rate of Wiktor stent implantation are overshadowed by a high incidence of subacute stent occlusion and bleeding complications.(ABSTRACT TRUNCATED AT 250 WORDS)     

Morphologic change in coronary artery stenosis with the medtronic Wiktor™ stent: Initial results from the core laboratory for quantitative angiography

The purpose of this study was to assess the early changes in stenosis geometry after implantation of the Medtronic Wiktor? stent in human coronary arteries. Morphologic changes were evaluated by quantitative coronary angiography using automated edge detection. The hemodynamlc significance of the morphologic changes were assessed by the calculation of the theoretical pressure drop across the dilated and stented stenosis derived from the Poiseuile and turbulent resistances assuming a coronary blood flow of either 0.5, 1, or 3 ml/sec. Fifty patients were studied before and immediately after stent implantation. The stented coronary artery was the left anterior descending artery in 26 patients, the circumflex artery in eight patients, and the right coronary artery in 16 patients. Stent implantation resulted in an additional increase in the minimal lumlnal cross-sectional area and minimal luminal diameter of the dilated vessel without changing the curvature of the stenosis. Furthermore, there was a significant reduction of the “plaque area.” This was associated with a normalization of the calculated resistances to flow and presure drop across the stenosis. To a minimal extent, recoil (0.1 ± 0.36 mm) was observed after stent implantation.     

Intracoronary Stenting for Restenosis: Long-Term Follow-up: A Single Center Experience

One-hundred thirteen stents (78 Wallstents, 29 Palmaz-Schatz and 6 Wiktor) were implanted in 106 patients aged 63 +/- 5 years to treat a restenosis following previous angioplasty in a native coronary artery (86 cases) and in a venous graft (20 cases). Implantation was technically possible in all cases. The native vessels had a mean reference diameter of 3.3 +/- 0.3 mm and their mean minimal lumen diameter increased from 1.2 +/- 0.3 mm before angioplasty to 2.8 +/- 0.8 after stent implantation. The venous grafts mean reference diameter was 4.4 +/- 0.7 mm and their mean minimal lumen diameter increased from 1.3 +/- 0.4 mm before angioplasty to 4.0 +/- 0.7 mm after implantation. Percentage stenosis in the native arteries and in the venous grafts were respectively 78 +/- 13% and 69 +/- 14% before angioplasty and 24 +/- 8% and 22 +/- 8% after stent implantation. Complications at 6 months, presented as a ranking scale with 100% follow-up rate were, overall, of 20% clinical events (4% deaths, 6% myocardial infractions, 2% coronary artery bypass grafting and 8% re-angioplasty). Angiographic complications were of 8% subacute thrombosis and 19% restenosis and chronic occlusions. Long-term, at 65 +/- 9 months, clinical (86% follow-up) and angiographic (74% follow-up) showed that only a further 9% clinical events and 14% restenosis (12% of them between 6 and 12 months) occurred after 6 months. At an estimated follow-up time of 104 months, 70% patients remain event-free and the survival rate is 95%. In conclusion, stent implantation in the treatment of restenosis following conventional balloon angioplasty is a valid strategy with good long-term results.     

Experimental Evaluation of a New Single Wire Tantalum Coil Coronary Stent (Wiktor-iª)

To improve scaffolding properties, a new more densely woven Wiktor stent, the Wiktor-ia stent, was developed. Although the metal coverage remains still low compared to other stents, increased metal/vessel area raises the concern of increased thrombogenicity and neointimal hyperplasia. In this study we evaluated the Wiktor-i stent in a porcine peripheral and coronary model and compared the thrombogenicity and neointimal hyperplasia with the Wiktor-GX coronary stent. In a first study, a Wiktor-i and a Wiktor-GX coronary stent were implanted symmetrically in a preselected side branch of the right and left iliac artery of 10 healthy pigs. Quantitative vessel analysis showed comparable data before, immediately after and at follow-up. Hyperplasia measured by morphometry was also comparable in both groups (Wiktor-GX: 1.43 mm2 vs. Wiktor-i: 1.17 mm2, NS). Also, area stenosis was very similar (Wiktor-GX: 32% vs. Wiktor-i: 29%, NS). In a second study, 20 Wiktor (Wiktor-i: n=10, Wiktor-GX: n=10) coronary stents were implanted in the right coronary artery of 20 healthy pigs. Quantitative coronary analysis before, immediately after and at follow-up was comparable in both stents. The hyperplasia measured morphometrically was also comparable in both stents. (Wiktor-GX: 1.51 +/- 0.47 mm2 vs. Wiktor-i: 1.46 +/- 0.66 mm2, NS). Also the area stenosis was not significantly different (Wiktor-GX: 31% vs. Wiktor-i: 35%). In conclusion, this study shows that the increased metal/vessel area of the Wiktor-i stent does not result in an increased neointimal hyperplasia. Both stents show to be very biocompatible when implanted in porcine coronary and peripheral vessels.     

Clinical experience with a new biocompatible phosphorylcholine-coated coronary stent

AIMS: The BiodivYsio stent is a new stent coated with phosphorylcholine, a biocompatible molecule designed to reduce the formation of thrombus and potentially the risk of restenosis. The feasibility, safety, and efficacy of elective and urgent implantation of this coated coronary stent were prospectively studied. METHODS AND RESULTS: We studied 224 patients who underwent elective (67%) or bail-out implantation of 303 BiodivYsio stents in 286 lesions. Most lesions (62%) had unfavorable characteristics (type B2 or C) and half of them (50%) had thrombus and/or chronic total occlusion. Clinical follow-up was obtained in all patients at one month and in the first 132 patients at six months. Repeat angiography was undertaken in all patients with recurrent ischemia. Successful stent deployment was achieved in 284 lesions (99.3%). One emergency coronary artery bypass graft (CABG) was required. Angiographic success rate was 98.3% (281/286). There was 1 (0.4%) subacute stent thrombosis associated with Q-wave myocardial infarction and two (0.9%) in-hospital deaths. Reference vessel diameter was 2.82 +/- 0.32 mm. Minimum luminal diameter (MLD) increased from 0.38 +/- 0.25 mm to 2.97 +/- 0.35 mm and diameter stenosis decreased from 83.8 +/- 12.1% to 5.8 +/- 9.7%. Clinical restenosis rate was 6.1% (8/132 patients) at 6-month follow-up. Target vessel revascularization rate at 6-month follow-up was 5.4%. CONCLUSIONS: This initial clinical experience indicates that the implantation of stents coated with phosphorylcholine appears to be safe and efficacious in the treatment of complex coronary lesions and is associated with an extremely low target vessel revascularization rate.     

Heparin-coated Wiktor stents in human coronary arteries (MENTOR trial). MENTOR Trial Investigators

The purpose of this study was to determine the feasibility, safety, and efficacy of elective stenting with heparin-coated Wiktor stents in patients with coronary artery disease. In experimental studies, heparin coating has been shown to prevent subacute thrombosis and restenosis. Recently, a new method of heparin coating was developed, resulting in a more stable and predictable heparin layer on stent devices. This trial constitutes the first in-human use of this coating procedure, applied on the well-known Wiktor stent device. Heparin-coated Wiktor stent implantation was performed in 132 consecutive patients (132 lesions) in a multicenter international trial from September 1996 to February 1997. Forty-three percent of patients had unstable angina, 33% had previous myocardial infarction, and 10% had diabetes mellitus. Patients were followed for 12 months for occurrence of major adverse cardiovascular events, and 96% of the eligible patients underwent quantitative angiographic control at 6 months. Stent deployment was successful in 95.5% of lesions. Minimal lumen diameter increased by 1.67 +/- 0.48 mm (from 1.02 +/- 0.38 mm before to 2.69 +/- 0.37 mm after the stent implantation). Mean percent diameter stenosis decreased from 67.4 +/- 11.3% before to 18.9 +/- 7.7% after the intervention. A successful intervention (<50% diameter stenosis and no major adverse cardiac events within 30 days) occurred in 97% of the patients. The subacute thrombosis rate was 0.8%, which compares favorably with historical controls of this stent, and a low incidence of postprocedural increase in creatine kinase-MB was noted. At 6 months, event-free survival was 85% and angiographic restenosis rate was 22% with late loss of 0.78 +/- 0.69 mm and a loss index of 0.48 +/- 0.44. Heparin-coated Wiktor stents appeared to be an efficacious device to treat Benestent-like lesions, yielding angiographic and clinical results comparable to a heparin-coated Palmaz-Schatz stent. Despite its use in more complex lesions, the incidence of subacute thrombosis appeared to be lower than historical controls with a similar noncoated stent.     

Preventive effects of the heparin-coated stent on restenosis in the porcine model.

The coronary stent reduces acute coronary arterial occlusion and late restenosis during and after coronary intervention. However, stent thrombosis and restenosis are still major limitations in the widespread use of the coronary stent. Local drug delivery using the heparin-coated stent may be a new approach, which reduces the incidence of stent thrombosis and restenosis. In order to evaluate the effects of the heparin-coated stent on stent restenosis, heparin-coated stents were compared with control stents in a porcine coronary stent restenosis model. Stent overdilation injury (stent:artery = 1.3:1.0) was performed with bare Wiktor stents (group I, n = 10) and heparin-coated Wiktor stents (group II, n = 20; HEPAMED, Medtronics) in porcine coronary arteries. Follow-up quantitative coronary angiography (QCA) was performed at 4 weeks after stenting, and histo-pathologic assessments of stented porcine coronary arteries were compared in both groups. On QCA, percent diameter stenosis was significantly higher in group I than in group II (16.3% +/- 6.62% vs. 9.6% +/- 5.06%, P < 0.05). The injury score of stented porcine coronary arteries was the same in both groups (1. 26 +/- 0.23 vs. 1.20 +/- 0.22). The area of pathologic stenosis of the stented arteries was higher in group I than in group II (41.6% +/- 12.5% vs. 27.1% +/- 9.9%, P < 0.005). The neointimal area was higher in group I than in group II (4.58 +/- 1.41 mm(2) vs. 2.57 +/- 1.07 mm(2), P < 0.05). By immunohistochemistry, the proliferating cell nuclear antigen (PCNA) index was higher in group I compared with group II (11.2% +/- 6.75% vs. 6.3% +/- 4.14%, P < 0.05). The heparin-coated stent is effective in the prevention of late coronary stent restenosis in a porcine coronary stent restenosis model. This may be related to the inhibition of neointimal cell proliferation.     

Randomized comparison of the coil-design Crossflex and the tubular NIR stent.

The purpose of this study was to compare the angiographic outcome of implantation of the coil-design Crossflex stent with the tubular NIR stent for treatment of coronary artery stenoses. Two hundred twenty-three patients with one genuine coronary artery lesion were randomized to implantation with a 15 mm Crossflex stent (n = 112) or a 16 mm NIR stent (n = 111). The patients had angiographic follow-up after 6 months. Primary endpoint was minimal luminal diameter (MLD) after 6 months. There was a similar clinical outcome in the two groups. At 6-month follow-up, the MLD was significantly lower in the Crossflex group (1.94 +/- 0.79 mm) than in the NIR group (2.37 +/- 0.84 mm; P < 0.001). Early gain was the same in the two groups. Late loss and percent diameter stenoses were significantly higher in the Crossflex group. The binary restenoses rate was 26% and 17% in the Crossflex and the NIR groups, respectively (P = NS). The coil-design Crossflex stent was found to be inferior to the tubular NIR stent concerning late loss and MLD at 6-month follow-up.     

Direct coronary stent implantation: safety, feasibility, and predictors of success of the strategy of direct coronary stent implantation.

This prospective study was designed to evaluate the feasibility, safety, predictive factors of success, and 6-month follow-up of stent implantation without balloon predilatation (direct stenting) in 250 patients undergoing elective stent implantation. Balloon dilatation prior to stent implantation was a prerequisite to facilitate passage and deployment of the stent. Stent technology has changed tremendously, resulting in stents with improved properties, which may allow stent placement without prior balloon dilatation. Patients with coronary lesions suitable for elective stent implantation were included in this trial. Coronary interventions were undertaken predominantly via the transradial route using 6 Fr guiding catheters. Direct stent implantation was attempted using AVE GFX II coronary stent delivery systems. Upon failure, predilatation was undertaken before reattempting stent implantation. Patient data and ECGs were obtained from case records and from personal or telephone interviews 6 months after the procedure. Values were presented as mean +/- standard deviation. Student's t-test, two-tailed at 5% level of significance, was used to compare the difference of two means. Multivariate logistic regression analysis was performed to establish predictive factors for failure of direct stenting. Two hundred and sixty-six direct stent implantations were attempted in 250 patients. Direct stenting was successful in 226 (85%) cases. Out of 40(15%) cases where direct stenting failed, balloon predilatation facilitated stent implantation in 39. In one lesion, stent implantation was not possible despite adequate predilatation. Predictive factors for failure of direct stenting on multivariate analysis were LCx lesions (P < 0.01), complex lesions (P < 0.01), and longer stents (P < 0.001). Minimal luminal diameter and percentage diameter stenosis of lesions in the successful and the failure group were not significantly different (0.94 +/- 0.39 mm vs. 0.84 +/- 0.41 mm, P = NS, and 70.2 +/- 11.2 vs. 73.2 +/- 11.2, P = NS). Stent loss occurred in five (2.0%) cases, with successful retrieval in four. One stent was lost permanently in a small branch of the radial artery. Post-percutaneous coronary intervention (post-PCI) myocardial infarction occurred in four (1.6%) patients. There were no other in-hospital events. Six-month-follow up information was obtained in 99% of patients. Subacute stent thrombosis was noted in four (1.6%) cases. Target vessel-related myocardial infarction rate was 3.2%, of which half was caused by subacute stent thrombosis. The overall reintervention rate (coronary artery bypass grafting or PCI) was 9.7%. Target lesion revascularization by PCI occurred in only 4.0%. At 6 months, overall mortality was 2.0%, of which 1.2% was due to coronary events. Direct stent implantation is safe and feasible in the majority of cases with low rate of complications. Unfavorable factors include circumflex lesion, more complex lesion morphology, and increasing length of stent. Severity of stenosis does not appear to be of predictive value. Long-term outcome is favorable with a low target lesion revascularization rate.     

Short- and long-term outcomes of Wiktor stent implantation at low versus high pressures. Austrian Wiktor Stent Study Group.

A prospective, randomized, multicenter trial was conducted to evaluate whether high-pressure postdilation of the Wiktor stent provides short- and long-term benefits compared with the conventional low-pressure implantation technique. From June 1995 through May 1996, 181 patients were randomly assigned to either low-pressure (6 to 12 atm, group A, n = 94) Wiktor stent placement or to high-pressure postdilation (> or = 13 atm, group B, n = 87) after stent deployment. All patients were followed up clinically for 7 +/- 3 months, with an angiographic follow-up in 154 patients (85%). After stent implantation, neither minimal lumen diameter (MLD) nor percent diameter stenosis (%DS) differed significantly between the 2 groups (MLD, 2.8 +/- 0.5 vs 2.9 +/- 0.5 mm; %DS, 17 +/- 8% vs 16 +/- 9% for groups A and B, respectively). However, a trend toward a larger mean lumen diameter within the stent was observed in group B (3.3 +/- 0.6 vs 3.5 +/- 0.5 mm for groups A and B, respectively; difference between means 0.14 mm, 95% confidence interval -0.01 to 0.29, p = 0.08). Angiographic follow-up revealed similar MLD and %DS in both treatment groups (MLD, 2.1 +/- 0.7 vs 2.2 +/- 0.8 mm; %DS, 31 +/- 17% vs 30 +/- 24% for groups A and B, respectively, p = NS). Acute stent thrombosis occurred in 2 patients (1%) (1 patient in each group), and subacute thrombosis in 1 patient (0.6%) in group A. There was 1 death in group A, and target lesion restenosis (> or = 50% DS) was observed in 15% of patients with no differences between the groups. In conclusion, this study demonstrated favorable short- and long-term results of Wiktor stent implantation. Despite a trend toward additional initial lumen gain by high-pressure postdilation, this did not translate into a measurable improvement in long-term outcome.     

Paclitaxel-eluting stent Taxcor: first application in man

AIM: The safety and efficacy of the second-generation paclitaxel-eluting stent with bioactive matrix Taxcor after implantation in de novo coronary lesions at 6 months is unknown. METHODS: In this single-center non-controlled study, 45 patients with mean de novo coronary lesions of 12.1+/-1.9 mm in length and mean reference diameter of 2.9+/-0.3 mm received the paclitaxel-eluting stent (Taxcor). Fifty stents were implanted. Clinical and angiographic follow-up were performed after 6 months. It was the first time that the Taxcor stent was applied in patients. RESULTS: Mean stent diameter was 3.0+/-0.3 mm and mean length 21.2+/-5.9 mm. Four patients did not consent to control angiography at 6 months. Mean minimal lumen diameter increased from 1.1+/-0.1 mm (pre-stent) to 2.7+/-0.3 mm (post-stent) and had slightly decreased to 2.4+/-0.6 mm at 6-month follow-up. Mean acute lumen gain was 1.6+/-0.3 mm. Mean reference-vessel diameter was 2.9+/-0.3 mm at all time points. Mean percentage-diameter stenosis decreased from 62.6%+/-5.6 (pre-stent) to 9.1+/-6.0% (post-stent) and had increased slightly to 18.4+/-6.5% after 6 months. Mean late lumen loss was 0.3+/-0.4 mm. All patients remained symptom-free during the 6-month follow-up with no cases of acute myocardial infarction or death reported. No procedure-related complications occurred and no acute or subacute stent thromboses were reported. Control angiography showed binary restenosis (percentage-diameter stenosis >50%) in one patient, in whom coronary intervention was performed subsequently. CONCLUSION: The paclitaxel-eluting stent Taxcor appeared to be effective and safe up to 6 months following implantation.     

Angiographic restenosis after successful Wallstent stent implantation: an analysis of risk predictors.

Follow-up angiographic study was performed in 86 patients after initially successful Wallstent stent (Medinvent, Lausanne, Switzerland) implantation between April 1986 and October 1990. The stent angiographic restenosis rate was 16% at a mean of 8 months after stenting despite the inclusion of a substantial number of patients at high risk of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Of a total 15 variables analyzed, only suboptimal stent placement was found to be a significant predictor of stent restenosis. Age; gender; baseline New York Heart Association functional class; previous PTCA; indication for stenting; left ventricular ejection fraction; preangioplasty and immediate postangioplasty diameter stenosis severity; stented vessel site, lesional morphology; number, diameter, and length of stents implanted; and the interval between stenting and follow-up angiographic restudy were not significant risk factors of stent restenosis. Our study suggests that intracoronary stent implantation with the Wallstent may be a useful and promising adjunctive option after PTCA, particularly in patients at high risk of restenosis after PTCA. However, because of the significantly enhanced risk of restenosis after suboptimal stent implantation, we strongly recommend the selection and placement of Wallstent stents that adequately cover the entire length of the dilated coronary segment.     

Early and late clinical and angiographic outcomes following terumo coronary stent implantation

The Terumo stent is a new, balloon-expandable, stainless-steel device with a unique multicellular design to provide robust radial force and end-stoppers to prevent dislodgement. We evaluated the early and late clinical and angiographic outcomes of Terumo coronary stent implantation in native coronary arteries using an open, nonrandomized 3-center registry. From July 1998 to June 1999, a total of 118 Terumo stents were implanted in 105 patients (mean age, 58 +/- 10 years). A significant proportion of patients suffered from diabetes (34%), prior myocardial infarction (MI; 43%) and unstable angina (31%). Most target lesions (48%) had unfavorable morphological characteristics (type B2 or C); mean reference luminal diameter was 2.76 +/- 0.41 mm and lesion length was 11.4 +/- 5.3 mm. Primary success in stent deployment was achieved in 103 patients (98%). There was 1 patient with acute stent thrombosis in whom 2 overlapping stents were deployed. Following stenting, the minimal luminal diameter increased from 1.04 +/- 0.48 mm to 2.39 +/- 0.33 mm. Six-month angiography was performed in 97 patients (92%), and the binary angiographic restenosis (> or = 50% narrowing) rate was 16%. Late loss index was 0.50 +/- 0.43. By 6 months, two patients (1.9%) died, two patients (1.9%) had Q-wave MI and 9 patients (8.4%) required repeat coronary interventions. Therefore, our study shows that the Terumo stent is potentially safe and efficacious in the treatment of coronary narrowings, even in the presence of unfavorable clinical conditions and complex lesion morphological characteristics.     

Long-term (> 3 years) clinical and angiographic outcomes of coronary multilink stent implantations: a single center experience

The ACS Multilink (ML) stent is a novel second-generation stent. The largest amount of information available on the long-term outcome of coronary stenting is based on the use of Palmaz-Schatz stents. Fewer data exist on long-term follow-up results of ML coronary stents implantations. The authors present the long-term (> 3 years) clinical and angiographic follow-up results of the ACS Multilink coronary stents implanted in their institution. From May 1996 to December 1997, 125 patients underwent 133 coronary ML stent implantations. Stented vessels were as follows: 49% left anterior descending artery, 31% right coronary artery, and 20% left circumflex coronary artery. Indications for stent implantations were elective in 64%, because of suboptimal result from percutaneous transluminal coronary angioplasty (PTCA) in 26%, and bailout from PTCA in 10% of patients. The mean reference diameter of stented vessels was 3.2 +/- 0.2 mm. The mean percentage stenosis was 80 +/- 11% and 3 +/- 5% before and after stent implantation, respectively. Long-term clinical follow-up was completed in 75% (80 men, mean age 53 +/- 10 years) of the patients (either by interview or phone), and angiographic follow-up (37 +/- 12 months) was completed in 58% of the patients. There were no baseline clinical or angiographic differences between those angiographically followed up and the remaining patients. Angiographic restenosis (> 50% diameter stenosis) was detected in 22% of stents. Target lesion revascularization was 12%, nontarget lesion revascularization was 14% in angiographically followed up patients. During the follow-up period death and new myocardial infarction occurred in 12% and 6% of patients, respectively, and survival rate was 88%. This study provides long-term follow-up results of intracoronary Multilink stent implantations for native coronary artery lesions. These data show that clinical and angiographic benefits of ML stents are comparable to those of the first-generation stents, especially to the Palmaz-Schatz stents, of which results have been reported previously. A considerable rate of nontarget lesion revascularization occurs during the follow-up period.     

The clinical results of a platelet glycoprotein IIb/IIIa receptor blocker (abciximab: ReoPro)-coated stent in acute myocardial infarction.

OBJECTIVES: This study is a prospective randomized trial investigating clinical outcomes of patients with acute myocardial infarction (AMI) treated with abciximab (ReoPro)-coated stents. BACKGROUND: Recently we have demonstrated that abciximab-coated stents have inhibitory effects in the prevention of coronary restenosis. METHODS: Ninety-six patients with AMI were randomly allocated into two groups; group I received abciximab-coated stents (n = 48, 57.1 +/- 12.0 years), and group II received bare metal control stents (n = 48, 58.4 +/- 11.6 years). RESULTS: At baseline, clinical characteristics, percent diameter stenosis, and minimal luminal diameter were no different between the two groups. One patient in group II had reinfarction and target lesion reintervention during hospital stay. Follow-up coronary angiography was obtained in 77.1% (37 of 48) in group I and 75.0% (36 of 48) in group II. Percent diameter stenosis and late loss were significantly lower in group I than group II (18.9 +/- 5.54% vs. 37.9 +/- 6.25%, p = 0.008; and 0.39 +/- 0.29 mm vs. 0.88 +/- 0.45 mm; p = 0.008, respectively). At follow-up intravascular ultrasound, intrastent lumen area and intrastent neointimal hyperplasia (NIH) area were 5.4 +/- 1.8 mm2 and 2.2 +/- 1.5 mm2, respectively, in group I and 4.3 +/- 1.6 mm2 and 3.4 +/- 1.8 mm2, respectively, in group II (p = 0.045). And, in-stent restenosis rate was lower in group I than group II (p = 0.011 and p = 0.008, respectively). During 1-year follow-up, two patients in group II (4.1%) had AMI, whereas no patient in group I suffered AMI. Target lesion revascularization and total major adverse cardiac events rates were relatively lower in group I compared with those in group II (10.4% [5 of 48] vs. 20.8% [10 of 48], p = 0.261, and 10.4% vs. 25.0%, p = 0.107, respectively). CONCLUSIONS: Abciximab-coated stent implantation was safe and effective without stent thrombosis in AMI patients.     

Endovascular stent implantation in the pulmonary arteries of infants and children without the use of a long vascular sheath.

Endovascular stent implantation for pulmonary artery stenosis requires the use of a long, large-bore vascular sheath to insure precise implantation without embolization or malposition. A long vascular sheath may be difficult to position and usage may be associated with vascular compromise and/or hemodynamic embarrassment, especially in infants and small children. We report a new technique for pulmonary artery endovascular stent implantation without the use of a long sheath. From December 2000 to May 2001, 10 patients underwent implantation of 13 Palmaz Corinthian premounted biliary transhepatic stents for pulmonary artery stenosis. Median age was 0.8 years (range, 0.5-18.5) and median weight was 11.8 kg (range, 4.6-65). Patient diagnoses were tetralogy of Fallot (five), double outlet right ventricle (three), branch peripheral pulmonary artery stenosis (two), single ventricle s/p cavopulmonary shunt (one), and truncus arteriosus (one). All Palmaz Corinthian stents were delivered uncovered on Cordis Opta LP balloon catheters via short sheaths (6-7 Fr); super-stiff guidewires were not always necessary. These stents, with a maximal expanded diameter of 12 mm, were placed for peripheral pulmonary artery stenosis as a definitive procedure or at the pulmonary artery bifurcation in patients who were expected to undergo future open heart surgery. The stents were initially implanted on 4, 6, or 8 mm balloon catheters and further expanded if needed. Stents were placed in the right pulmonary artery alone in three patients, left pulmonary artery alone in four patients, and side-by-side stents were implanted simultaneously in three patients. All thirteen stents were implanted successfully in the desired location without stent malposition or embolization. Mean angiographic diameter increased from 2.5 +/- 1.5 to 5.7 +/- 1.4 mm (P < 0.01) and peak systolic ejection gradients decreased from 44 +/- 22 to 14 +/- 11.6 mm Hg (P < 0.01). The uncovered delivery of the premounted Palmaz Corinthian stent allowed for precise and safe endovascular stent implantation without the hemodynamic and technical problems associated with long vascular sheath usage. This technique is useful for the palliation of proximal pulmonary artery stenosis and is effective definitive treatment for peripheral pulmonary artery stenosis in small infants and children.     

Expansion of the Multilink-Tristar stent after direct implantation and predilatation: comparison of clinical,angiography and intravascular ultrasound parameters

Coronary stenting has become the primary therapeutic option for many coronary lesions. As opposed to conventional stenting the advantages of direct stenting are a reduction of procedural time, radiation exposure and costs. However, data about the incidence of in-stent restenosis are so far not available. It was the aim of this prospective study to compare the expansion of the Multilink stent after direct stenting and predilatation by quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS). Between January 2000 and June 2001, 82 patients were assigned to direct stenting (46 lesions) or predilatation (40 lesions) in lesions of coronary arteries > 3 mm. The procedural success rate was 92% in patients undergoing direct stenting. The baseline clinical characteristics were similar in both groups. The comparison of the angiographic data shows that direct stenting was performed in lesions with a lower degree of stenosis (71 +/- 12% vs 79 +/- 11%, p = 0.01) and that significantly shorter stents were used (14.4 +/- 3.0 vs 17.8 +/- 4.1 mm, p = 0.0007). The mean stenosis length was not significantly different in either group (10.5 +/- 3.4 vs 11.7 +/- 4.3 mm, n.s.). The QCA data after stent implantation show no differences of either implantation technique. Stent expansion was assessed by IVUS estimation of the proximal, distal and minimal in stent area. The minimal in-stent area (9.53 +/- 3.23, mm2 vs 8.65 +/- 1.96 mm2, n.s.) and the stent symmetry index (0.88 vs 0.88 n.s.) were not different in either patient group. These results indicate that in this subset of selected coronary lesions > 3 mm, elective stent implantation with and without predilatation effectively can achieve comparable stent expansion as assessed by QCA and IVUS. In comparison to conventional stent implantation stents, which were implanted without predilatation, were significantly shorter to cover the same lesion length.     

Clinical and angiographical follow-up after implantation of a 6--12 microCi radioactive stent in patients with coronary artery disease.

AIMS: This study is the contribution by the Thoraxcenter, Rotterdam, to the European(32)P Dose Response Trial, a non-randomized multicentre trial to evaluate the safety and efficacy of the radioactive Isostent in patients with single coronary artery disease. METHODS AND RESULTS: The radioactivity of the stent at implantation was 6--12 microCi. All patients received aspirin indefinitely and either ticlopidine or clopidogrel for 3 months. Quantitative coronary angiography measurements of both the stent area and the target lesion (stent area and up to 5 mm proximal and distal to the stent edges) were performed pre- and post-procedure and at the 5-month follow-up. Forty-two radioactive stents were implanted in 40 patients. Treated vessels were the left anterior descending coronary artery (n=20), right coronary artery (n=10) or left circumflex artery (n=10). Eight patients received additional non-radioactive stents. Lesion length measured 10+/-3 mm with a reference diameter of 3.07+/-0.69 mm. Minimal lumen diameter increased from 0.98+/-0.53 mm pre-procedure to 2.29+/-0.52 mm (target lesion) and 2.57+/-0.44 mm (stent area) post-procedure. There was one procedural non-Q wave myocardial infarction, due to transient thrombotic closure. Thirty-six patients returned for angiographical follow-up. Two patients had a total occlusion proximal to the radioactive stent. Of the patent vessels, none had in-stent restenosis. Edge restenosis was observed in 44%, occurring predominantly at the proximal edge. Target lesion revascularization was performed in 10 patients and target vessel revascularization in one patient. No additional clinical end-points occurred during follow-up. The minimal lumen diameter at follow-up averaged 1.66+/-0.71 mm (target lesion) and 2.12+/-0.72 (stent area); therefore late loss was 0.63+/-0.69 (target lesion) and 0.46+/-0.76 (stent area), resulting in a late loss index of 0.65+/-1.15 (target lesion) and 0.30+/-0.53 (stent area). CONCLUSION: These results indicate that the use of radioactive stents is safe and feasible, however, the high incidence of edge restenosis makes this technique currently clinically non-applicable.