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At least 19 recordsLinked to original sources
PubMed2005

Shortening the stent length reduces restenosis with bare metal stents: matched pair comparison of short stenting and conventional stenting.

OBJECTIVE: To investigate the effect of reducing stent length on the rate of target lesion restenosis. DESIGN: In a prospective investigation, acute and long term results of a short stenting procedure were analysed by quantitative angiography and compared with results of a conventional stenting procedure selected according to a matched pairs analysis. PATIENTS: Short stents were implanted in 400 consecutive patients with 464 lesions and conventional stents in 430 patients. Demographic and lesion characteristics were comparable between groups. INTERVENTIONS: In short stenting, the shortest stent length to cover only segments with > 30% reduction in vessel diameter was used. In conventional stenting, full coverage of a stenotic vessel segment was intended. MAIN OUTCOME MEASURES: The mean stent lengths of the short stent group (9.8 (4) mm) and the conventional stent group (16.3 (7) mm) differed significantly (p < 0.0001); all other procedural and angiographic parameters were the same. Procedural success was similar for both groups. Control angiography after six months was conducted in 92% of patients. RESULTS: Short stenting resulted in both less restenosis (68 of 431 (15.8%)) than conventional stenting (93 of 381 (24.4%), p = 0.007) and less late lumen loss (0.6 (0.6) mm v 0.75 (0.5) mm, p = 0.0001). Residual stenosis (< 45%) in adjacent vessel segments after short stenting did not affect the restenosis rate. Only the implantation of a < or = 9 mm stent predicted the absence of restenosis in a multivariate analysis. CONCLUSION: Shortening the length of bare metal stents reduces the restenosis rate as compared with conventional stenting.

Angina Pectoris↗
PubMed2000

Stenting the stent: initial results and long-term clinical and angiographic outcome of coronary stenting for patients with in-stent restenosis.

Stent restenosis constitutes a therapeutic challenge affecting an increasing number of patients. Conventional angioplasty and debulking techniques are currently used in these patients. However, the potential role of a second stent implantation in this setting (stenting the stent) remains unknown. Therefore, 65 consecutive patients (12 women, aged 62 +/- 11 years) undergoing stent implantation (42 elective and 23 unplanned) for the treatment of in-stent restenosis (diffuse [> 10 mm] in 39 [60%]) were studied. Angiographic success was obtained in all patients. Three patients developed hospital complications: 1 died from refractory heart failure and 2 suffered non-Q-wave myocardial infarctions. During follow-up (mean 17 +/- 11 months) 1 patient died (noncardiac cause) and only 9 (14%) required target vessel revascularization. Kaplan-Meier event-free survival (freedom from death, myocardial infarction, and target vessel revascularization) at 1 year was 84%. Using Cox analysis, patients with unstable symptoms, a short time to stent restenosis, nonelective stenting, and B2-C lesions tended to have poorer prognosis. After adjustment, nonelective stenting was associated (adjusted RR 2.9, 95% confidence interval [CI] 0.82 to 10.3, p = 0.09) with an adverse clinical outcome. On quantitative angiography (core lab) restenosis was found in 13 of 43 patients (30%) (75% of those eligible). Logistic regression analysis identify restenosis length (adjusted RR 1.43, 95% CI 1.04 to 2.14, p = 0.04), and time to restenosis (adjusted RR 0.67, 95% CI 0.47 to 0.94, p = 0.01) as the only independent predictors of recurrent restenosis. Thus, repeat coronary stenting is a safe and efficacious strategy for the treatment of patients with in-stent restenosis. Both elective and nonelective stenting provide excellent initial results. The long-term clinical and angiographic outcome of these patients is also favorable.

Coronary Angiography↗
PubMed2004

Therapeutic implications of in-stent restenosis located at the stent edge. Insights from the restenosis intra-stent balloon angioplasty versus elective stenting (RIBS) randomized trial.

AIMS: In patients with in-stent restenosis (ISR) several anatomic subgroups have been identified. ISR affecting the stent edge (EDG) is a poorly characterised subgroup with undefined therapeutic implications. We sought to determine the implications of ISR affecting the stent EDG. METHODS AND RESULTS: 450 patients included in the "Restenosis Intra-stent: Balloon angioplasty vs elective Stenting" (RIBS) randomized study, were analysed. EDG ISR was predefined in the protocol and the pattern of ISR analysed in a centralized core-lab. Fifty-two patients (12%) had EDG ISR (29 stent group, 23 balloon arm). Patients with EDG ISR had less severe [minimal lumen diameter (MLD) (0.78+/-0.3 vs 0.66+/-0.3 mm, p=0.05)] and shorter lesions (lesion length 10.2+/-6 vs 13.2+/-7 mm, p=0.003). Patients with EDG ISR more frequently required crossover (12% vs 3%, p=0.006) but eventually the immediate angiographic result and the long-term clinical and angiographic outcome was similar to that found in patients without EDG ISR. Patients with EDG ISR treated in the balloon and stent arms had similar baseline characteristics. However, after intervention, the immediate angiographic result was better in the stent arm (MLD 2.79+/-0.4 vs 2.35+/-0.3 mm, p=0.001). This difference persisted at late follow-up: MLD (1.93+/-0.7 vs 1.39+/-0.7 mm, p=0.01), recurrent restenosis (20% vs 50%, p=0.03). In addition, the 1-year event-free survival was significantly better (83% vs 52%, log rank p=0.01; Cox HR 0.28, 95%CI 0.09-0.79) in the stent arm. Moreover, stent implantation was an independent predictor of freedom from target vessel revascularization (HR 0.15, 95%CI 0.03-0.67, p=0.003). CONCLUSIONS: EDG ISR constitutes a specific subgroup with relevant therapeutic implications. In patients with EDG ISR, repeat stent implantation provides better clinical and angiographic outcome than conventional balloon angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed2003

Low restenosis rate of the NIR coronary stent: results of the Danish multicenter stent study (DANSTENT)--a randomized trial comparing a first-generation stent with a second-generation stent.

BACKGROUND: Larger studies evaluating the angiographic results of second-generation stents are scarce. The objectives of this study were to assess current standards of angiographic and clinical outcomes after implantation of the second-generation stainless steel stent, NIR (Medinol Ltd, Tel Aviv, Israel), and to compare the outcomes with those of the first-generation Palmaz-Schatz (PS) stent (Johnson & Johnson, Warren, NJ). METHODS: Patients having coronary artery lesions that could be covered by a stent of 15 mm in length were randomly assigned to receive the NIR or the PS. Procedural success, 6-month angiographic findings, and 1-year clinical outcomes were determined. RESULTS: In 424 patients included in the study, the overall procedural success rate was high (NIR 98%, PS 99%, P =.90). Follow-up angiography was conducted in 91% of the patients. The overall rate of angiographic restenosis was low in both groups (NIR 9.9%, PS 12.6%, P =.35). We found a low restenosis rate in vessels with a minimal lumen diameter >3.1 mm after the procedure, particularly in the NIR group (<6%). The rate of target lesion revascularization after 1 year did not differ (NIR 12%, PS 10%, P =.47). CONCLUSIONS: The angiographic and clinical outcomes after implantation of the second-generation stainless steel stent were not significantly better than those of the first-generation stent. The low restenosis rates, particularly in patients with the largest minimal lumen diameters after stent implantation, warrants circumspection when planning the evaluation of newer stent technologies that aim to further reduce coronary restenosis.

Angina Pectoris↗
PubMed2006

Single-vessel versus bifurcation stenting for the treatment of distal left main coronary artery disease in the drug-eluting stenting era. Clinical and angiographic insights into the Rapamycin-Eluting Stent Evaluated at Rotterdam Cardiology Hospital (RESEARCH) and Taxus-Stent Evaluated at Rotterdam Cardiology Hospital (T-SEARCH) registries.

BACKGROUND: Routine drug-eluting stent (DES) implantation has recently improved outcome in patients undergoing percutaneous treatment of left main (LM) coronary artery. However, even in the DES era, distal LM treatment remains an independent predictor of poor outcome. Whether single-vessel stenting (SVS) or bifurcation stenting (BS) should be performed to optimize treatment of such a lesion is unclear. METHODS: From April 2002 to June 2004, 94 patients affected by distal LM disease underwent percutaneous intervention at our institution either with SVS (n = 48) or BS (n = 46). The 2 groups were well balanced for all baseline characteristics but the extension of disease in the LM carina. RESULTS: After a median follow-up of 587 days (range, 328-1179), the cumulative incidence of MACE was similar between the 2 groups (31% in the BS vs 28% in SVS group, HR 0.96, 95% CI 0.46-1.49, P = .92), with no difference for the composite death/myocardial infarction or target vessel revascularization. After adjustment for confounders, the technique of stenting was not a predictor of either major adverse cardiac events or target vessel revascularization. Angiographic analysis--performed in 81% of eligible patients in SVS and 87% in the BS group--confirmed the equivalency between SVS versus BS. CONCLUSIONS: In consecutive patients undergoing catheter-based distal LM intervention, SVS or BS may perform equally under both clinical and angiographic perspective in current DES era.

Aged↗
PubMed1999

Difference in security of stent jail between Palmaz-Schatz, NIR, and Multi-Link stents: the effect of balloon inflation through stent struts.

After placing a stent in the main vessel of a bifurcation lesion, it is often necessary to perform further balloon inflation or stent placement through the stent struts in order to treat a lesion of the secondary vessel or side branch. This balloon inflation with dilatation through the cells of the stent in the main vessel results in stent strut disfigurement. This disfigurement causes various degrees of stenosis within the main vessel secondary to stent strut deformity. The degree of strut deformity, and therefore stenosis, may vary significantly depending on stent design and structure. A model of a bifurcation lesion with an angle of 45 degrees was created from acrylic resin. The diameters of the main vessel and the secondary vessel were both 3.5 mm. Deployment of the Palmaz-Schatz stent (PS, n = 5), NIR stent (n = 5), or Multi-Link stent (n = 5) was performed in the main vessel with a 3.5-mm balloon catheter inflated to 6 atm. A second 3.5-mm balloon catheter was then inflated to 6 atm through the stent struts of the main vessel and into the ostium of the secondary vessel. The minimal lumen diameter (MLD) and cross-sectional area (CSA) at the ostium of the side branch and the stenosis within the main vessel were then measured, taking into account the stent deformity that occurred. Kissing balloon dilatation with two 3.5-mm balloon catheters was then performed and the stenosis secondary to stent deformity in the main vessel was remeasured. The MLD of the Multi-Link stent at the side-branch ostium was greater compared with those of the Palmaz-Schatz stent or the NIR stent (2.4 +/- 0.1, 1.6 +/- 0.1, 1.7 +/- 0.1 mm, P < 0.01) and CSA (4.9 +/- 0.5, 2.7 +/- 0.3, 2.5 +/- 0.3 mm(2), P < 0.01). Balloon inflation through the stent struts caused stent deformity that resulted in some degree of stenosis within the stent of the main vessel in all three stent types. Kissing balloon inflation reduced, but never eliminated, this stenosis. The percent stenosis in the main vessel secondary to stent deformity (PS 34% +/- 9%, NIR 25% +/- 8%, Multi-Link 34% +/- 7%, NS) and residual stenosis postkissing balloon inflation (PS 12% +/- 1%, NIR 10% +/- 3%, Multi-Link 14% +/- 3%, NS) were not significantly different among these three stents. At the side-branch ostium, the MLD and CSA were significantly greater for the Multi-Link stent compared with those of the Palmaz-Schatz or NIR stent. Balloon inflation through the stent struts caused stent deformity that resulted in stenosis within the stent in the main vessel. Kissing balloon inflation reduced this stenosis, but some residual stenosis always remained. The stenoses within the main vessel did not differ among the three stent types. Cathet. Cardiovasc. Intervent. 48:230-234, 1999.

Angioplasty, Balloon, Coronary↗
PubMed2005

Sirolimus-eluting stent or paclitaxel-eluting stent vs balloon angioplasty for prevention of recurrences in patients with coronary in-stent restenosis: a randomized controlled trial.

CONTEXT: In patients with de novo coronary lesions, drug-eluting stents have drastically reduced restenosis risk compared with bare metal stents and conventional balloon angioplasty. It is less clear whether drug-eluting stents are superior to conventional balloon angioplasty for the treatment of patients with in-stent restenosis. OBJECTIVES: To assess if drug-eluting stents are a more effective treatment of in-stent restenosis than conventional balloon angioplasty, and to assess the relative merits of 2 drug-eluting stents, a sirolimus-eluting stent and a paclitaxel-eluting stent. DESIGN, SETTING, AND PARTICIPANTS: Randomized, open-label, active-controlled trial conducted among 300 patients with angiographically significant in-stent restenosis in 2 tertiary German centers from June 1, 2003, to October 20, 2003. INTERVENTIONS: After pretreatment with 600 mg of clopidogrel for at least 2 hours before intervention, all patients were randomly assigned to 1 of 3 treatment groups: sirolimus stent, paclitaxel stent, or balloon angioplasty (100 patients in each group). MAIN OUTCOME MEASURES: Primary end point: angiographic restenosis (diameter stenosis > or =50%) at 6-month follow-up angiography based on "in-segment" analysis. Primary analysis was comparison between stent groups and balloon angioplasty groups; a secondary analysis compared sirolimus and paclitaxel stents. RESULTS: Follow-up angiography was performed in 275 (92%) of 300 patients. The incidence of angiographic restenosis was 44.6% (41/92) in the balloon angioplasty group, 14.3% (13/91) in the sirolimus stent group (P<.001 vs balloon angioplasty), and 21.7% (20/92) in the paclitaxel stent group (P = .001 vs balloon angioplasty). When compared with balloon angioplasty, receiving a sirolimus stent had a relative risk (RR) of angiographic restenosis of 0.32 (95% confidence interval [CI], 0.18-0.56); a paclitaxel stent had an RR of 0.49 (95% CI, 0.31-0.76). The incidence of target vessel revascularization was 33.0% (33/100) in the balloon angioplasty group, 8.0% (8/100) in the sirolimus stent group (P<.001 vs balloon angioplasty), and 19.0% (19/100) in the paclitaxel stent group (P = .02 vs balloon angioplasty). The secondary analysis showed a trend toward a lower rate of angiographic restenosis (P = .19) and a significantly lower rate of target vessel revascularization (P = .02) among sirolimus stent patients compared with paclitaxel stent patients. CONCLUSIONS: In patients with in-stent restenosis, a strategy based on sirolimus- or paclitaxel-eluting stents is superior to conventional balloon angioplasty for the prevention of recurrent restenosis. Sirolimus-eluting stents may be superior to paclitaxel-eluting stents for treatment of this disorder.

Aged↗
PubMed2005

Long-segment SFA stenting--the dark sides: in-stent restenosis, clinical deterioration, and stent fractures.

PURPOSE: To determine and compare the rates of in-stent restenosis, late clinical deterioration, and stent fractures in nitinol stents versus Wallstents implanted for suboptimal angioplasty in the superficial femoral artery (SFA). METHODS: Interrogation of an angioplasty database identified 286 consecutive patients (178 men; mean age 67+/-10 years, range 44-87) with severe claudication (n=254) or critical limb ischemia (n=32) who had stents implanted after suboptimal angioplasty over a 5-year period. Wallstents with a mean stented lesion length of 107+/-71 mm were implanted in 116 patients, while nitinol stents were used in 170 patients: 45 SMART stents (mean stented lesion length 139+/-88 mm) and 125 Dynalink/Absolute stents (mean stented lesion length 125+/-84 mm). Patients were followed for in-stent restenosis (>50%) by duplex ultrasound, clinical deterioration by at least 1 Fontaine stage compared to baseline, and stent fractures by biplanar radiography. RESULTS: In-stent restenosis rates at 1, 2, and 3 years were 46%, 66%, and 72% for Wallstents compared to 20%, 36%, and 53% for nitinol stents (p<0.001), respectively, without significant difference between the 2 nitinol stent groups (p=0.59). Clinical deterioration at 1, 2, and 3 years was found in 10%, 15%, and 18% with Wallstents versus 4%, 5%, and 5% with nitinol stents (p=0.014), respectively, without difference between the 2 nitinol stent groups (p=0.47). Fracture rates were 19% for Wallstents after a mean 43+/-24 months, 28% for SMART stents after mean 32+/-16 months, and 2% for Dynalink/Absolute stents after a mean 15+/-9 months. CONCLUSIONS: Intermediate-term in-stent restenosis remains a major problem even with current nitinol stent technology; however, clinical deterioration seems no matter of serious concern with SMART and Dynalink/Absolute stents. Stent fractures may be lower with Dynalink/Absolute stents, but randomized head-to-head comparisons are needed to validate these data.

Adult↗
PubMed2005

Comparison of thrombosis and restenosis risk from stent length of sirolimus-eluting stents versus bare metal stents.

Selection of coronary stent length varies from covering only the zone of maximum obstruction to stenting from normal- to normal-appearing vessels. With bare metal stenting, for any given lesion there is a high restenotic risk associated with longer stent length. With drug-eluting stents, the relation between stent length and restenosis has not been evaluated. In the angiographic follow-up cohort of the SIRIUS trial that compared the sirolimus-eluting Bx Velocity stent with the standard Bx Velocity stent (n = 699), we constructed a multiple regression model to predict 8-month percent diameter stenosis using the main effects of lesion length and excess stent length beyond the lesion length and adjusting for known predictors of restenosis. Stent length exceeded lesion length in 94% of lesions overall. Mean difference in length was 8.3 +/- 8.3 mm (mean lesion length 14.6 +/- 5.9 mm, mean stent length 22.9 +/- 9.6 mm). Stented lesion length and excess stent length were associated with absolute increases in percent diameter stenosis per 10 mm of 9.1% (p <0.0001) and 3.6% (p = 0.053) in the bare metal arm and 3.5% (p = 0.047) and 2.1% (p = 0.040) in the sirolimus-eluting stent arm. Although the effects of lesion length and excess stent length on restenosis were markedly decreased with sirolimus-eluting stents (vs bare metal stents), a small restenotic penalty is still paid for excessive stent length. Longer stent-to-lesion length strategies should be used only when a shorter stent is likely to result in incomplete lesion coverage and edge dissection, a strong determinant of stent thrombosis.

Angioplasty, Balloon, Coronary↗
PubMed1999

Stent attachment site-related endoleakage after stent graft treatment: An in vitro study of the effects of graft size, stent type, and atherosclerotic wall changes.

OBJECTIVE: Perigraft endoleakage is a major complication of the endovascular treatment of abdominal aortic aneurysms. The factors that cause this form of endoleakage are not completely identified. The effect of sizing of the prosthesis in combination with either self-expandable or balloon-expandable stents is evaluated in this study. Further, the influence of atherosclerotic changes on endoleakage is evaluated. METHODS: Eight human abdominal aortas were assessed macroscopically at 11 sites for the presence of atherosclerotic changes with intravascular ultrasound scanning (IVUS) and with computed tomography (CT). Five aortas were placed in in vitro circulation with physiologic parameters. After the determination of the proximal and distal landing site of the stent graft, the diameter and surface measurements of the cross sections were taken. The stent graft diameters were chosen from 4-mm undersizing to 6-mm oversizing, both for Gianturco stent grafts (William Cook Europe A/S, Bjaeverskov, Denmark) and for Palmaz stent grafts (Cordis/Johnson & Johnston Co, Warren, NJ). After placement of the stent graft, the diameter and surface measurements of the aortic cross section were determined at the proximal and distal stent attachment sites. The presence and size of the folds at the stent attachment site and the interface with the aortic wall were determined with IVUS and angioscopy. Endoleakage was evaluated with angiography. After angioplasty of the stent attachment site, IVUS, angioscopy, and angiography were repeated. RESULTS: Regarding atherosclerotic changes of the aortic wall, the correlations between clinical impression and CT, clinical impression and IVUS, and CT and IVUS were high (r = 0.77, r = 0.79 and r = 0.79, respectively). For the Gianturco stent grafts, no significant relationship existed between the diameters measured before and after stent graft placement, leading to great differences in intended and achieved oversizing. The achieved oversizing was less in the case of minimal atherosclerotic changes of the aortic wall. The Gianturco stent graft followed the aortic wall closely during the heart cycle. The sizes of the folds of the fabric were clearly correlated with the achieved oversizing (r = 0.83; P =.04) and the grade of endoleakage (r = 0.88; P =.022). Angioplasty after stent graft placement had no effect on the diameter and the grade of endoleakage. Palmaz stent grafts did not follow the aortic wall during the heart cycle. A significant correlation existed between oversizing and both space between aortic wall and stent graft (r = -0.88; P =.02) and grade of endoleakage (r = 0.84; P =.036). Grade of endoleakage in the Palmaz stent graft group was less than in the Gianturco stent graft group. CONCLUSION: With the use of Gianturco stents, a great difference between intended and achieved oversizing is accomplished. The atherosclerotic changes of the aortic wall possibly affect this finding. The configuration of the Gianturco stent results in the formation of fold in the case of oversizing, which is associated with endoleakage. However, the self-expandable character of the stent leads to a close relation to the aortic wall during the heart cycle, and this may possibly accommodate future aortic neck dilation. The Palmaz stent grafts do not follow the aortic wall during the heart cycle, but they do lead to better interface between the graft and the aortic wall, which results in less endoleakage.

Angioscopy↗
PubMed2004

Spiral stent versus standard stent in patients with midsize renal stones treated with extracorporeal shock wave lithotripsy: which stent works better? A prospective randomized trial.

PURPOSE: It has been proposed that stone fragment clearance with a new spiral Double-J stent (Medical Engineering Corp., New York, New York) is faster than with a standard Double-J stent. Therefore, we evaluated stent insertion, peri-interventional complications, as well as stone clearance in patients with midsize kidney stones treated with extracorporeal shock wave lithotripsy (3,500 shock waves) in a prospective randomized trial. MATERIALS AND METHODS: A total of 32 patients were randomized for preoperative insertion of a spiral stent (16) or a standard stent (16). Stone volume was measured from an abdominal plain film. Stent inserting time and stent handling problems, as well as perioperative and postoperative complications were evaluated. Clearance of stone fragments was analyzed by abdominal plain films and ultrasound on day 1, and at the end of weeks 1, 2 and 6 after treatment or until stone fragments were completely cleared. RESULTS: Median stone volume was 1.8 ccm (range 0.4 to 5.2) in the spiral stent group and 1.3 ccm (range 0.4 to 2.6) in the standard stent group (p = 0.08). Median stent inserting time was 21 minutes (range 10 to 60) in the spiral stent and 18 minutes (range 5 to 45) in the standard stent group (p = 0.94). Inserting difficulties occurred in 6 of 16 (38%) patients with spiral stents and in none with standard stents (p = 0.005). Spontaneous stent displacement occurred in 4 of 16 patients in the spiral stent group and did not occur in the standard stent group (p = 0.03). The percentage of stone-free patients 1 day, and 1, 2 and 6 weeks after treatment was 0%, 13%, 44% and 81% in the spiral stent group and 6%, 19%, 50% and 88% (p = 0.64) in the standard stent group, respectively. CONCLUSIONS: Spiral stents are more difficult to insert, spontaneously dislocate more often and have no advantage in overall stone clearance compared with standard stents.

Adolescent↗
PubMed2006

Comparison of the efficacy of direct coronary stenting with sirolimus-eluting stents versus stenting with predilation by intravascular ultrasound imaging (from the DIRECT trial).

A direct coronary stenting technique using drug-eluting stents may decrease drug-eluting stent efficacy due to possible damage to the surface coating of the stent. The DIRECT is a multicenter, prospective, nonrandomized trial designed to evaluate the direct stenting strategy for the sirolimus-eluting Bx-Velocity stent compared with the historical control (SIRIUS trial, stenting with predilation). Volumetric and cross-sectional intravascular ultrasound analyses at 8-month follow-up were performed in 115 patients (DIRECT n= 64, control n = 51). Patient and lesion characteristics were comparable between groups. The DIRECT group achieved an equivalent uniform expansion index, defined as minimum stent area/maximum stent area x 100, compared with the control group (65.9 +/- 11.7 vs 63.1 +/- 12.7, p = NS). At 8-month follow-up, vessel, stent, lumen, and neointimal volume index (volume in cubic millimeters/length in millimeters) and percent neointimal volume were similar between the DIRECT and control groups (vessel volume index 13.9 +/- 4.40 vs 15.0 +/- 3.83; stent volume index 6.83 +/- 2.02 vs 6.94 +/- 2.04; lumen volume index 6.71 +/- 2.04 vs 6.81 +/- 2.07; neointimal volume index 0.14 +/- 0.24 vs 0.16 +/- 0.23; percent neointimal volume 3.73 +/- 6.97 vs 3.14 +/- 5.32, p = NS for all). In addition, in-stent neointimal hyperplasia distribution was significantly smaller near the distal stent edge (0.22 vs 0.098 mm(3)/mm, p = 0.01 for an average neointimal volume index within 3 mm from the distal stent edge). In conclusion, direct coronary stenting with the sirolimus-eluting Bx-Velocity stent is equally effective in terms of uniform stent expansion and long-term quantitative intravascular ultrasound results compared with conventional stenting using predilation. This strategy appears to be associated with less neointimal hyperplasia near the distal stent edge.

Coronary Stenosis↗
PubMed2002

Relation of stent design and stent surface material to subsequent in-stent intimal hyperplasia in coronary arteries determined by intravascular ultrasound.

A variety of different stent designs and coatings have become available. This study sought to determine the impact of stent design and gold-coating of stents on intimal hyperplasia (IH) in human atherosclerotic coronary arteries in relation to known predictors of restenosis. Angiographic and intravascular ultrasound (IVUS) studies were performed at 6-month follow-up on 311 native coronary lesions of 311 patients treated with 99 Multi-Link stents, 74 InFlow steel stents, 73 InFlow gold-coated stents, 41 Palmaz-Schatz stents, 12 NIR steel stents, and 12 gold-coated NIR Royal stents. Lumen and stent cross-sectional area (CSA) were measured at 1-mm axial increments. Mean IH CSA (stent CSA - lumen CSA) and mean IH thickness were calculated and averaged over the total stent length. IVUS demonstrated different levels of IH for the 6 stents. Mean IH thickness ranged from 0.20 +/- 0.13 mm for Multi-Link stents to 0.43 +/- 0.14 mm for InFlow goal-coated stents (p <0.001). Multivariate analysis proved non-Multi-Link stent design (odds ratio 3.45, 95% confidence intervals 1.13 to 11.11, p <0.034) and gold coating (odds ratio 3.78, 95% confidence intervals 1.88 to 7.54, p <0.001) to be the only independent predictors of IH thickness >0.3 mm. In conclusion, stent design and surface material have an important impact on the IH response to stents implanted in human coronary arteries. However, the differences in IH thickness between the analyzed stents were relatively small compared with the absolute lumen dimensions.

Analysis of Variance↗
PubMed2005

Time course of release of inflammatory markers after coronary stenting: comparison between bare metal stent and sirolimus-eluting stent.

BACKGROUND: High levels of release of inflammatory markers after coronary angioplasty are predictors of late restenosis. Sirolimus-eluting stent reduces the risk of restenosis. AIM OF THE STUDY: To compare the release of inflammatory markers after coronary angioplasty with sirolimus-eluting stent and bare metal stent. METHODS: Sixteen patients with a proximal left anterior descending coronery artery stenosis were randomly assigned to receive either bare metal stent (n = 8) or sirolimus-eluting stent (n = 8). We measured simultaneously aortic and coronary sinus concentrations of the von Willebrand factor antigen, tumor necrosis factor-alpha and interleukin-6 before, immediately and after 2 h after stenting. High-sensitivity C-reactive protein and troponin-I circulating levels were measured before and 6 and 24 h after coronary angioplasty. RESULTS: Before stenting, all values were similar in both groups. The coronary sinus change of the von Willebrand factor antigen level between baseline and 2 h after stenting was + 20.1 +/- 26.9% in the bare metal stent group and -5.7 +/- 23.02% in the sirolimus-eluting stent group (P < 0.05). We observed a significant increase in the von Willebrand factor antigen (from 132.8+/-58.8 to 169 +/- 40.7%, P < 0.05) systemic concentrations 24 h after stenting in the bare metal stent group but not in the sirolimus-eluting stent group (from 140.6+/-84% to 136 +/- 39.5%), P = NS). CONCLUSION: The present study shows that a difference in the release of inflammatory markers can be detected after coronary stenting with bare metal stent or sirolimus-eluting stent. The lower release of the von Willebrand factor antigen in the coronary sinus 2 h after the procedure and the lower systemic concentrations of the von Willebrand factor antigen 24 h after stenting in the sirolimus-eluting stent group are likely to reflect a reduced production of the von Willebrand factor antigen at the site of the vascular injury.

Antigens↗
PubMed2006

In vitro evaluation of metallic coronary artery stents with sub-millimeter multi-slice computed tomography using an ECG-gated cardiac phantom: relationship between in-stent visualization and stent type.

The aim of this experimental study was to investigate visualization of various coronary artery stents with sub-millimeter multi-slice spiral computed tomography (MSCT) using a cardiac physical phantom. Four 3-mm stents of various designs were implanted in tubes with an inner diameter of 3 mm to simulate coronary artery. Stents were placed on a cardiac phantom and scanned at different heart rates. Retrospective ECG-gated adaptive segmental reconstruction technique was employed. Profile curves across longitudinal curved planar reconstruction images of the stents were generated. From the profile curve, the full width at half maximum was defined as the stent lumen index. The effect of heart rate and stent type on the stent lumen index was evaluated. Visual evaluation for each stent at various heart rates was also performed. The heart rate had no significant effect on in-stent visualization. However, in-stent visualization differed significantly for the various stent types for both profile curve analysis and visual evaluation (the Tukey-Kramer multiple comparisons test). Multiple regression analysis indicated that strut thickness, especially minimal strut thickness, was the significant influencing factor for the in-stent visualization. On the basis of four stent models examined it would appear that visualization of the coronary stent lumen varies depending on the stent type, but not on the heart rate. Stents with slim struts are preferable for in-stent evaluation with multi-slice spiral computed tomography.

Biocompatible Materials↗
PubMed2006

Paclitaxel-eluting stents vs vascular brachytherapy for in-stent restenosis within bare-metal stents: the TAXUS V ISR randomized trial.

CONTEXT: Restenosis within bare-metal stents is often treated with repeat percutaneous coronary intervention, although subsequent recurrence rates are high, with vascular brachytherapy (VBT) affording the best results. The effectiveness of drug-eluting stents in this setting has not been established. OBJECTIVE: To investigate the safety and efficacy of the polymer-based, slow-release paclitaxel-eluting stent in patients with restenotic lesions after prior stent implantation in native coronary arteries. DESIGN, SETTING, AND PATIENTS: Prospective, multicenter, randomized trial conducted between June 6, 2003, and July 16, 2004, at 37 North American academic and community-based institutions in 396 patients with in-stent restenosis of a previously implanted bare-metal coronary stent (vessel diameter, 2.5-3.75 mm; lesion length, < or =46 mm). INTERVENTIONS: Patients were randomly assigned to undergo angioplasty followed by VBT with a beta source (n = 201) or paclitaxel-eluting stent implantation (n = 195). Clinical and angiographic follow-up at 9 months was scheduled in all patients. MAIN OUTCOME MEASURE: Ischemia-driven target vessel revascularization at 9 months. RESULTS: Diabetes mellitus was present in 139 patients (35.1%). Median reference vessel diameter was 2.65 mm and median lesion length was 15.3 mm. In the VBT group, new stents were implanted in 22 patients (10.9%) and in the paclitaxel-eluting stent group, multiple stents were required in 57 patients (29.2%), with median stent length of 24 mm. Follow-up at 9 months was complete in 194 patients in the VBT group and 191 patients in the paclitaxel-eluting stent group (96.5% and 97.9%, respectively). For VBT and paclitaxel-eluting stents, respectively, the number of events and 9-month rates for ischemic target lesion revascularization were 27 (13.9%) vs 12 (6.3%) (relative risk [RR], 0.45; 95% confidence interval [CI], 0.24-0.86; P = .01); for ischemic target vessel revascularization, 34 (17.5%) vs 20 (10.5%) (RR, 0.60; 95% CI, 0.36-1.00; P = .046); and for overall major adverse cardiac events, 39 (20.1%) vs 22 (11.5%) (RR, 0.57; 95% CI, 0.35-0.93; P = .02), with similar rates of cardiac death or myocardial infarction (10 [5.2%] vs 7 [3.7%]; RR, 0.71; 95% CI, 0.28-1.83; P = .48) and target vessel thrombosis (5 [2.6%] vs 3 [1.6%]; RR, 0.61; 95% CI, 0.15-2.50; P = .72). Angiographic restenosis at 9 months was 31.2% (53 of 170 patients) with VBT and 14.5% (25 of 172 patients) with paclitaxel-eluting stents (RR, 0.47; 95% CI, 0.30-0.71; P<.001). CONCLUSION: Treatment of bare-metal in-stent restenotic lesions with paclitaxel-eluting stents rather than angioplasty followed by VBT reduces clinical and angiographic restenosis at 9 months and improves event-free survival. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00287573.

Aged↗
PubMed2002

Late coronary stent thrombosis: early vs. late stent thrombosis in the stent era.

The incidence of coronary stent thrombosis is < 1%-2% in recent studies, with the highest-risk period considered to be the first 30 days following stent implantation. Recently, stent thrombosis after 30 days has been reported in patients undergoing brachytherapy with stenting. We reviewed the incidence of stent thrombosis causing myocardial infarction in nonbrachytherapy patients at our institution between 1 January 1996 and 30 November 1999. A case control methodology was employed with a 1:3 ratio of stent thrombosis to control patients. Of 1,191 patients undergoing coronary stenting, acute (< 24 hr) plus subacute (1-30 days) stent thrombosis occurred in 0.92% (11 of 1,191 patients). A further 0.76% (9 of 1,191 patients) developed late stent thrombosis after 30 days. There were no clinical or angiographic features at the time of the initial procedure that were associated with stent thrombosis as an entire group compared with control group, but early (acute and subacute) stent thrombosis patients had a smaller final stent minimal lumen diameter and longer stent length compared with patients who had late stent thrombosis or controls. Late stent thrombosis occurs in nonbrachytherapy patients and is almost as frequent as early stent thrombosis. Further studies are required to determine whether longer-term poststent pharmacological treatment may decrease or prevent this complication.

Biomarkers↗
PubMed2001

Effects of 32P radioactive stents on in-stent restenosis in a double stent injury model of the porcine coronary arteries.

BACKGROUND: The major limitation of coronary stenting remains in-stent restenosis, due to the development of neointimal proliferation. Radioactive stents have demonstrated the ability to reduce this proliferation in the healthy nonatherosclerotic porcine animal model. However, inhibition of tissue proliferation in the in-stent restenotic lesion in a porcine model is not well characterized. The objective of this study was to examine the efficacy and safety of the 32P radioactive stent for the treatment of in-stent restenosis in a double stent injury model of the porcine coronaries. METHODS AND MATERIALS: Eighteen coronary arteries in 9 pigs underwent nonradioactive stent (8 mm in length) implantation. Thirty days after the initial stent implantation, a 32P radioactive stent (18 mm in length) with an activity of 0 and 18 microCi was implanted to cover the initial stent. The swine were killed 30 days after the second stent implantation. Histomorphometric analysis was performed for vessel area (VA), stent strut area (SSA), intimal area (IA), and lumen area (LA). RESULTS: Injury scores, VA, SSA, and LA were similar among the control and radiated groups. Neointimal formation was significantly reduced after placement of radioactive stents as compared to control in both the overlapped (0.93 +/- 0.12 vs. 1.31 +/- 0.51 mm(2), p < 0.05) and nonoverlapped segments (1.14 +/- 0.21 vs. 1.91 +/- 1.04 mm(2), p < 0.05). The smooth muscle cell index in the neointima was reduced. Intimal fibrin was increased in the radiated group as compared to the control (p < 0.01 respectively). CONCLUSIONS: 32P radioactive stents may be safe and effective in reducing neointimal formation leading to in-stent restenosis. Longer follow-up will be required to examine whether these positive findings can be maintained.

Animals↗