Stent restenosis in a Chinese population

BACKGROUND: Stents are now widely used in Hong Kong and China and there is a clinical impression that restenosis is less common because of the lower prevalence of coronary artery disease and associated risk factors in the Chinese. However, there are no published data on angiographic stent restenosis rates in Chinese patients. METHOD: In a prospective study of 114 consecutive Chinese patients who underwent coronary stenting, quantitative coronary analyses were made at the time of stent implantation and subsequently at 6 months post-stenting (n = 97). RESULTS: At 6 months, restenosis (> or = 50% diameter stenosis in the dilated segment) was present in 42 (43.3%) of the 97 patients and 54 (33.5%) of the total 161 lesions stented. Vessel reference diameter (VRD) of < 3 mm and stented length of > or = 18 mm were associated with higher restenosis rates (36% and 38%). Compared to those without, those with restenosis had a greater residual stenosis of 16.53+/-11.54% and smaller final minimal luminal diameter (MLD) of 2.41+/-0.49 mm, (p < 0.01 and p < 0.008 respectively). Standard coronary risk factors were not associated with a higher rate of restenosis. Lesion morphology was significantly associated with restenosis. CONCLUSION: Coronary stenting in Hong Kong Chinese patients is associated with a restenosis rate comparable to that demonstrated in previously published trials from populations in the West.     

Coronary stenting or balloon angioplasty for chronic total coronary occlusions: the Taiwan experience (a single-center report)

The authors conducted this study to compare the restenosis and reocclusion rates of primary balloon angioplasty alone versus angioplasty followed by stenting in Taiwanese patients with chronic total occlusions. They also evaluated whether stenting reduced the incidence of restenosis and improved left ventricular function in these patients. From October 1998 to April 2000, a total of 294 patients with chronic total occlusion (Thrombolysis in Myocardial Infarction grade 0 flow) underwent recanalization using balloon angioplasty alone or followed by stent implantation. Of these, only 129 patients were included after procedural failure and patients lost to follow-up; 62 patients were placed in the stent group, while 67 patients were assigned to the percutaneous transluminal coronary angioplasty (PTCA) group. Coronary angiography was performed at baseline and at 6 months follow-up or earlier if angina or objective evidence of ischemia involving the target vessel or other vessels was present. Procedural success was 60%. Minimal lumen diameter increased significantly after stenting: 2.97 +/-0.41 vs 2.24 +/-0.41 (p < 0.001); 60% of patients in the stent group were free of restenosis, whereas only 33% in the PTCA group were free of restenosis at follow-up. Only 1 patient in the stent group had reocclusion, as opposed to 17 (25%) patients in the PTCA group (p < 0.001). The follow-up minimal lumen diameter (MLD) at 6 months was significantly larger in the stent group: 1.80 +/-0.85 mm vs 1.08 +/-0.82 mm (p < 0.001). Left ventricular function improved in the stent group, but not in the PTCA group (58.44 +/-16.58% to 63.60 +/-14.59% [p < 0.001] vs 54.13 +/-15.66% to 54.31 +/-15.60% [p = 0.885]). More patients had angina in the PTCA group than in the stented group 43 vs 29 (p = 0.053). The postprocedural MLD and reference vessel diameter (RVD) were the strong predictors of restenosis and follow-up MLD (p < 0.001). Stenting of chronically occluded arteries significantly reduced the incidence of reocclusion and restenosis, at the same time improving left ventricular function in these patients. This should be the procedure of choice after successful angioplasty of chronically occluded vessels.     

A randomized comparison of repeat stenting with balloon angioplasty in patients with in-stent restenosis

OBJECTIVES: This randomized trial compared repeat stenting with balloon angioplasty (BA) in patients with in-stent restenosis (ISR). BACKGROUND: Stent restenosis constitutes a therapeutic challenge. Repeat coronary interventions are currently used in this setting, but the recurrence risk remains high. METHODS: We randomly assigned 450 patients with ISR to elective stent implantation (224 patients) or conventional BA (226 patients). Primary end point was recurrent restenosis rate at six months. Secondary end points included minimal lumen diameter (MLD), prespecified subgroup analyses, and a composite of major adverse events. RESULTS: Procedural success was similar in both groups, but in-hospital complications were more frequent in the balloon group. After the procedure MLD was larger in the stent group (2.77 +/- 0.4 vs. 2.25 +/- 0.5 mm, p < 0.001). At follow-up, MLD was larger after stenting when the in-lesion site was considered (1.69 +/- 0.8 vs. 1.54 +/- 0.7 mm, p = 0.046). However, the binary restenosis rate (38% stent group, 39% balloon group) was similar with the two strategies. One-year event-free survival (follow-up 100%) was also similar in both groups (77% stent vs. 71% balloon, p = 0.19). Nevertheless, in the prespecified subgroup of patients with large vessels (> or =3 mm) the restenosis rate (27% vs. 49%, p = 0.007) and the event-free survival (84% vs. 62%, p = 0.002) were better after repeat stenting. CONCLUSIONS: In patients with ISR, repeat coronary stenting provided better initial angiographic results but failed to improve restenosis rate and clinical outcome when compared with BA. However, in patients with large vessels coronary stenting improved the long-term clinical and angiographic outcome.     

Evaluation of restenosis in major vessels and side branches

OBJECTIVES: The indications for concurrent intervention for stenosis of a side branch during the treatment for stenosis of the main vessel were investigated using quantitative coronary angiography. METHODS: The retrospective study included 451 patients treated for a stenotic main vessel incorporating a side branch, who underwent follow-up angiography within 6 months. Patients were divided into Group I with the side branch treated by coronary angioplasty, and Group II with the side branch left untreated. Quantitative coronary angiography was used to measure the minimum luminal diameter (MLD) and percentage diameter stenosis (%DS) of the main vessel and the side branch. RESULTS: The MLD of the side branch after treatment was larger in Group I (1.4 +/- 0.1 mm) than in Group II (0.7 +/- 0.1 mm), and the %DS of the side branch after treatment was smaller in Group I (34 +/- 3%) than in Group II (63 +/- 2%). These differences decreased at follow-up to 1.1 +/- 0.1 mm, 48 +/- 2% in Group I; 0.9 +/- 0.04 mm, 46 +/- 2% in Group II, respectively. The MLD and %DS of the side branch at follow-up in Groups I and II were affected by the presence of main vessel restenosis[Restenosis(+): 0.9 +/- 0.1 mm, 57 +/- 4%; restenosis(-): 1.2 +/- 0.1 mm (p < 0.05), 43 +/- 3% (p < 0.05) in Group I; Restenosis(+): 0.9 +/- 0.1 mm, 51 +/- 8%; restenosis(-): 1.0 +/- 0.1 mm, 44 +/- 3% in Group II]. Multivariate analysis showed that %DS of the main vessel at follow-up was the only powerful predictor of restenosis of the side branch (p = 0.0249, odds ratio = 1.031, confidence interval = 1.004-1.059) in Groups I and II. CONCLUSIONS: Restenosis of the main vessel rather than the initial outcome of the side branch is the major influence on restenosis of the side branch.     

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.     

Intracoronary β-irradiation prevents excessive in-stent neointimal proliferation in de novo lesions of patients with high plasma ACE levels. The BetAce randomized trial

BACKGROUND: This study evaluated vascular brachytherapy (VBT) as a potent antiproliferative treatment to prevent in-stent restenosis (ISR) after coronary angioplasty of de novo lesions in patients carrying the D allele of the I/D polymorphism of the ACE gene and high ACE plasma levels (>34 U/l). METHODS AND MATERIALS: A prospective randomized trial was designed to detect a 30% improvement in the minimal lumen diameter (MLD) of the stenotic artery, as measured by quantitative coronary analysis (QCA), 6 months following VBT at the time of stented angioplasty. All patients were carriers of the D allele of the ACE gene, with plasma ACE levels >34 U/l. RESULTS: Thirty-one patients (33 stenoses) were allocated to stent implantation (control group) and 30 patients (31 stenoses) to VBT and stented angioplasty. After angioplasty, in-stent MLD was similar in the two groups. At 6 months in the control group, in-stent MLD had decreased to 1.74+/-0.8 versus 2.25+/-1.05 mm in the VBT group (P=.04). The mean in-stent diameter was 2.3+/-0.8 mm in the control group versus 2.9+/-1.05 mm after VBT (P=.02), and the restenosis rate was 37.5% versus 17.9%, respectively (P=.08). At 6 months, a higher need for target vessel revascularization (TVR) was observed in the control group: 35.5% versus 13.3% (P=.04). CONCLUSIONS: This randomized study confirms that patients with high plasma ACE concentrations are exposed to an increased risk for ISR after coronary stenting. The preventive use of VBT in these patients reduced neointimal formation by 65% such that the MLD at follow-up was increased by 29% compared with the control group.     

Stenting of Nonacute Total Coronary Occlusions: Predictors of Late Angiographic Outcome

Objectives. This study was designed to determine and assess factors predictive of the intermediate-term outcome of stenting of nonacute total coronary occlusions.Background. Balloon angioplasty of recanalized coronary occlusions is associated with a combined restenosis/reocclusion rate of up to 65%. Adjunctive stenting holds the potential to reduce this rate significantly. However, variables affecting the late angiographic outcome of coronary stenting in the setting of a total occlusion have not been elucidated sufficiently.Methods. Coronary stenting was performed in 143 consecutive patients with a nonacute total occlusion; 120 of these patients (84%), with a total of 121 occlusions, underwent repeat angiography within 6 months and comprised the study group. High pressure stent implantation aimed to cover the site of the occlusion as well as adjacent diameter stenoses ≥70% and all possibly induced dissections. Pertinent angiographic and procedural variables obtained at the time of the intervention were entered into a multivariate logistic regression analysis model to assess their influence on the angiographic outcome at follow-up.Results. Mean preinterventional reference lumen diameter for the 121 vessels was 2.99 ± 0.53 mm (mean ± SD); occlusion length ranged from 4 to 44 mm (median of 7.7). After balloon angioplasty, dissections were found in 80% of patients. Lesions were covered with stents a median of 16 mm in length (range 8 to 53). The minimal lumen diameter (MLD) achieved after stenting was 2.89 ± 0.48 mm. After a median follow-up period of 4.5 months, mean MLD was assessed at 1.91 ± 0.90 mm, corresponding to a loss index of 0.34 ± 0.31. There were 27 vessels with a nonocclusive restenosis ≥50% and 8 with a reocclusion, for a combined restenosis/reocclusion rate of 29%. Factors found to adversely influence angiographic outcome were a post-stenting MLD ≤2.54 mm, a stented vessel segment length >16 mm, a balloon/vessel diameter ratio for final stent expansion ≤1.00 and the presence of a dissection after balloon angioplasty.Conclusions. Compared with previous reports on stand-alone balloon angioplasty, stenting of nonacute total coronary occlusions lowers the 6-month restenosis/reocclusion rate to ∼30%. The late procedural outcome is independently and statistically significantly influenced by the MLD after stenting, the length of the stented vessel segment, the balloon/vessel diameter ratio for final stent expansion and the incidence of dissections after balloon angioplasty.     

Long-term follow-up of primary stenting with coil stent in acute myocardial infarction

The authors evaluated clinical and angiographic outcomes for 1 year after primary stenting using coil stent for acute myocardial infarction. Twenty-eight patients underwent primary stenting with coil stent. Follow-up coronary arteriography at 3 months and 1 year was planned in all patients. Procedural success was achieved in 96%. There was no acute or subacute thrombosis. Minimal lumen diameter (MLD) was increased from 0.08 +/- 0.19 to 2.73 +/- 0.49 mm after stenting. MLD had decreased significantly for 3 months (MLD at 3 months: 2.03 +/- 0.86 mm, p = 0.001). On the other hand, MLD did not differ between 3-month; and 1-year follow-up (MLD at 1 year: 2.26 +/- 0.73 mm, p = NS). Only one patient manifested reocclusion at 3-month follow-up. The cumulative restenosis rate and target lesion revascularization rate at 1-year follow-up were 25.9% (7/27) and 11.1% (3/27). Primary stenting using coil stent is safe and feasible in patients with acute myocardial infarction and may improve clinical outcome and decrease restenosis and target lesion revascularization rate.     

Predictors of recurrent restenosis after coronary stenting: an analysis of 197 patients

One of the major limitations in coronary stenting is in-stent restenosis. This study was aimed to identify clinical, angiographic, and procedural factors that may be related to recurrent in-stent restenosis. We analyzed consecutive 197 patients who underwent coronary stenting. Follow-up angiography was available in 170 patients and repeat balloon angioplasty was performed for in-stent restenosis. These patients were subdivided into 3 groups: group A consisted of 100 patients that were never restenosed, group B had 49 patients restenosed once, and in group C were 21 patients restenosed more than twice. Group C was more often female (48%) and included diabetes mellitus patients (52%). Lesion location, reference vessel size and diameter stenosis were similar for all groups. However, the incidence of calcified lesions tended to be higher (50% vs. 29%; p = 0.07), and lesion length was longer in group C than in group A (11.9+/- 5.4 mm vs. 9.0+/- 3.9 mm; p < 0.01). Diameter stenosis after predilation as well as after stenting was significantly higher in group C than in group A (50+/- 10% vs 39+/- 10%; p < 0.01, 32+/- 8% vs. 19+/- 10%; p < 0.01). The incidence of diffuse type of in-stent restenosis was significantly higher in group C than in group B (62% vs. 14%; p < 0.01). Multivariate logistic regression analysis identified diameter stenosis after stenting (p = 0.0022), female (p = 0.0135), and diameter stenosis after predilatation (p = 0.0233) as the significant correlate of recurrent in-stent restenosis. In conclusion, the major recurrent in-stent restenosis predictors identified included female gender, final diameter stenosis, and diameter stenosis after predilatation.     

Incidence and predictors of late total occlusion following coronary stenting

To determine the incidence and predictors of total occlusion in‐stent restenosis, we reviewed three randomized stent vs. stent trials and one stent registry, which provided 955 coronary artery lesions with 6‐month angiographic follow‐up. Fifteen (1.6%) of the 955 stented lesions were totally occluded at 6‐month follow‐up. Most patients with total occlusion presented with recurrent angina at the time of repeat angiography (60.0%) while no patient presented with an acute ST segment elevation myocardial infarction. The univariate predictors of total occlusion following elective coronary stenting included stenting for restenosis after a previous percutaneous intervention (P = 0.001), longer stent length (P < 0.001), longer lesion length (P < 0.001), smaller reference vessel diameter (P = 0.022), smaller preprocedure minimum lumen diameter (MLD; P = 0.004), and smaller postprocedure MLD (P = 0.036). Stepwise multiple logistic regression analysis demonstrated that stenting for restenotic lesions (P = 0.004), longer stent length (P < 0.001), and smaller preprocedure MLD (P = 0.012) were independent predictors of total occlusion following coronary stenting. Catheter Cardiovasc Interv 2003;60:344‐351. © 2003 Wiley‐Liss, Inc.     

Luminal recovery from six to twelve months after implantation of "thicker strut" coronary stents

A group of 50 patients with 51 de novo lesions treated with thicker strut stents (strut thickness >100 microm) was angiographically evaluated at baseline, after stenting, and at 6 and 12 months. Minimal luminal diameter (MLD) significantly increased from 6 to 12 months (6 months: 1.72 +/- 0.50 mm vs 12 months: 1.81 +/- 0.47 mm; p <0.01). The binary restenosis (diameter stenosis >50%) rate was 17% at 6 months and 11% at 12 months (p = NS). At multivariate analysis, lumen loss at 6 months (p = 0.018) and deployment pressure (p = 0.041) independently predicted the changes in MLD between 6 and 12 months.     

Long-term follow-up after coronary stenting and intravascular red laser therapy

A high restenosis rate remains a limiting factor for coronary angioplasty and stenting. Recently, use of intravascular red light therapy (IRLT) has been shown to be effective in different animal models and in humans in reducing the restenosis rate. Sixty-eight patients were treated with IRLT in conjunction with coronary stenting procedures. Mean age was 64 +/- 9 years. Treated lesions were type A (11), type B (42), and type C (18) with a mean lesion length of 16.5 +/- 2.4 mm. Reference vessel diameter and minimal lumen diameter (MLD) before therapy were 2.90 +/- 0.15 and 1.12 +/- 0.36 mm, respectively. After stenting and laser irradiation, MLD was 2.76 +/- 0.39 mm. No procedural complications or in-hospital adverse events occurred. All patients were followed up as depicted in the protocol. Sixty-one patients underwent angiographic restudy, which revealed restenosis in 9 patients (14.7%). Observed restenosis rate by artery size was > 3 mm (n = 21, 0%), 2.5 to 3.0 mm (n = 28, 14.2%), and <2.5 mm (n = 12, 41.6%). We conclude that IRLT is safe and feasible and reduces the expected restenosis rate in patients after coronary stenting in arteries of >2.5 mm.     

Valsartan for prevention of restenosis after stenting of type B2/C lesions: the VAL-PREST trial

The following study was performed to evaluate the effects of chronic 6-month administration of the angiotensin I receptor antagonist valsartan on restenosis rate after stenting of type B2/C lesions in comparison to placebo. Despite encouraging results of the BENESTENT and STRESS trials, stenting of complex coronary lesions leads to an in-stent restenosis rate of up to 40%. Several attempts at systematic medical therapy (e.g., ACE inhibitors) have not improved these results. Because of the important role of angiotensin in endothelial function, the hypothesis that angiotensin I receptor antagonists after stent implantation lead to a reduction of the in-stent restenosis rate should be tested in a single-center trial. Two hundred and fifty patients with type B2/C coronary lesions were randomized in an open-label study with respect to age, gender, lesion type and indication of percutaneous coronary intervention to a chronic administration of 80 mg valsartan or placebo (beta-blocking agents and/or ACE inhibitors). In-stent restenosis rate according to quantitative coronary angiography (QCA) and need for reintervention as primary and secondary endpoints were analyzed after a repeat angiogram at 6 months in 99 patients with 80 mg valsartan and 101 patients with placebo. Chronic administration of 80 mg valsartan reduced the in-stent restenosis rate to 19.2% (n = 19/99) in comparison to placebo with an in-stent restenosis rate of 38.6% (n = 39/101) (p < 0.005). Reintervention rate was 28.7% (n = 29/101) in the placebo group and only 12.1% (n = 12) in the valsartan group (p < 0.005). QCA analysis of stented coronary segments disclosed no differences in reference vessel diameter (2.68 +/- 0.26 mm in the valsartan group versus 2.71 +/- 0.24 mm in the placebo group) but significant differences in stented vessel diameter (2.17 +/- 0.27 mm in the valsartan group and 1.60 +/- 0.20 mm in the placebo group) (p < 0.000001).     

Standardized angiographically guided over-dilatation of stents using high pressure technique optimize results without increasing risks

BACKGROUND: Routine angio-guided stent deployment results in a relatively high restenosis rate, which is mostly due to stent sub-expansion. Several different intravascular ultrasound (IVUS) criteria for optimal stent deployment have been proposed. A minimal in-stent restenosis and a minimal in-stent lumen area of > or = 9 mm2 have been associated with low rates of restenosis and target lesion revascularization (TLR) at 6 months. The role of high-pressure stent deployment and/or upsizing the post-dilatation balloon has not yet been clarified. The aim of this study was to evaluate the possibility of achieving accepted IVUS criteria safely without IVUS guidance with the combination of high-pressure deployment and post-dilatation with a 0.25 mm oversized balloon. METHODS: Thirty-four stents (26 NIR, 3 AVE GFX, 3 ACS GFX, 1 Bard, 1 Jostent) were implanted in 30 patients until optimal angiographical results were obtained (< 10% residual stenosis visually). Forty percent of the patients had unstable angina pectoris, forty-four percent had complex lesions (B2 and C) and 29% were occlusions. Mean inflation pressure was 12.6 +/- 1.6 atm, mean stent diameter was 3.2+/- 0.4 mm and mean stent length was 15.1+/- 5.4 mm. Post-dilatation was performed with the same stent using a short (compared to the angiographic reference segment), 0.25 mm oversized Scimed Maxxum Energy 3.5 +/- 0.4 mm balloon using high pressure (16.1 +/- 1.7 atm) followed by an off-line IVUS examination of the stents. There was clinical follow-up for 1 year. Results in patients with single-vessel disease were compared with those of non-randomized controls, who were stented with high pressure but without over-dilatation. RESULTS: No stent achieved the nominal diameter, in spite of over-dilatation. Mean minimal stent diameter (MLD) according to IVUS was 2.9 +/- 0.4 mm (92% of the angiographic reference diameter). Mean minimal lumen area (MLA) was 7.7 +/- 2.2 mm2. An in-stent MLA > or = 90% of the distal reference segment (AVID criteria) and an MLA > or = 100% or > or = 90% of the smallest/average reference segment (MUSIC criteria) was found in 67% and 57%, respectively. MLA > or = 9 mm2 was achieved in 38%. All stents had good apposition and obtained a symmetry index > or = 0.7 mm. No acute perforations, dissections or other serious complications occurred during the over-dilatation. At 1 year, five patients had re-angina leading to a new coronary angiography; only 1 patient had a significant in-stent restenosis requiring re-PTCA. Compared to non-overdilated historical controls, the standardized over-dilatation seemed to give a larger MLD (3.0 +/- 0.4 mm vs. 2.7 +/- 0.4 mm; p = 0.03), more patients who fulfilled AVID criteria (70% vs. 32%; p = 0.048) and more stents with MLA > or = 9 mm2 (46% vs. 11%; p = 0.02). CONCLUSION: A standardized 0.25 mm over-dilatation of stents never achieved nominal stent size, but did improve lumen gain and was associated with low target vessel revascularization without adding complications to the routine stenting procedure.     

The French Randomized Optimal Stenting Trial: a prospective evaluation of provisional stenting guided by coronary velocity reserve and quantitative coronary angiography. F.R.O.S.T. Study Group

OBJECTIVES: We sought to make a prospective comparison of systematic stenting with provisional stenting guided by Doppler measurements of coronary velocity reserve and quantitative coronary angiography. BACKGROUND: Despite the increasing use of stents during percutaneous transluminal coronary angioplasty, it is unclear whether systematic stenting is superior to a strategy of provisional stenting in which stents are placed only in patients with unsatisfactory results or as a bail-out procedure. METHODS: Two hundred fifty-one patients undergoing elective coronary angioplasty were randomly assigned either to provisional stenting (group 1, in which stenting was performed if postangioplasty coronary velocity reserve was <2.2 and/or residual stenosis > or =35% or as bail-out) or to systematic stenting (group 2). The primary end point was the six-month angiographic minimal lumen diameter (MLD). Major adverse cardiac events were secondary end points (death, acute myocardial infarction and target lesion revascularization). RESULTS: Stenting was performed in 48.4% of patients in group 1 and 100% of patients in group 2 (p<0.01). Six months after angioplasty, the MLD did not differ between groups (1.90+/-0.79 mm vs. 1.99+/-0.70 mm, p = 0.39), as was the rate of binary restenosis (27.1% vs. 21.4%, p = 0.37). Among patients with restenosis, 13/32 (40.6%) in group 1 but 100% (25/25) in group 2 had in-stent restenosis (p<0.01). Target lesion revascularization (15.1% vs. 14.4% in groups 1 and 2 respectively, p = 0.89) and major adverse cardiac events (15.1% vs. 16.0%, p = 0.85) were not significantly different. CONCLUSIONS: Systematic stenting does not provide superior angiographic results at six months as compared with provisional stenting.     

Effects of stent length and lesion length on coronary restenosis

The choice of drug-eluting versus bare metal stents is based on costs and expectations of restenosis and thrombosis risk. Approaches to stent placement vary from covering just the zone of maximal obstruction to stenting well beyond the lesion boundaries (normal-to-normal vessel). The independent effects of stented lesion length, nonstented lesion length, and excess stent length, on coronary restenosis have not been evaluated for bare metal or drug-eluting stents. We analyzed the angiographic follow-up cohort (1,181 patients) from 6 recent bare metal stent trials of de novo lesions in native coronary arteries. Stent length exceeded lesion length in 87% of lesions (mean lesion length 12.4 +/- 6.3 mm, mean stent length 20.0 +/- 7.9 mm, mean difference 7.6 +/- 7.9 mm). At 6- to 9-month follow-up, the mean percent diameter stenosis was 39.1 +/- 20.1%. In an adjusted multivariable model of percent diameter stenosis, each 10 mm of stented lesion length was associated with an absolute increase in percent diameter stenosis of 7.7% (p <0.0001), whereas each 10 mm of excess stent length independently increased percent diameter stenosis by 4.0% (p <0.0001) and increased target lesion revascularization at 9 months (odds ratio 1.12, 95% confidence interval 1.02 to 1.24). Significant nonstented lesion length was uncommon (12.5% of cases). In summary, stent length exceeded lesion length in most stented lesions, and the amount of excess stent length increased the risk of restenosis independent of the stented lesion length. This analysis supports a conservative approach of matching stent length to lesion length to reduce the risk of restenosis with bare metal stents.     

Comparison of cutting balloon vs stenting alone in small branch ostial lesions of native coronary arteries.

Angioplasty of small vessels is associated with a higher rate of restenosis, even in the ostium. The present study compared the acute, late results of cutting balloon vs those of stenting alone in small branch ostial lesions of native coronary arteries and the effect on the parent vessel. The study group comprised 61 patients with successful angioplasty of smaller branch ostial lesions in native coronary arteries. The reference vessel diameter was between 2.5 and 3.0 mm. Patients were divided into 2 groups: group I (cutting balloon, n=30) and group II (stenting alone, n=31). After intervention, patients in group II achieved significant acute lumen gain, larger minimal lumen diameter (MLD) and less diameter stenosis. At 3-month follow-up, the MLD and diameter stenosis of the 2 groups were almost identical; however, late loss was lower in group I. At the 6-month follow up, the cumulative restenosis rate was 41% (11/27) in group I compared with 63% (19/31) in group II (p=0.05), and the target lesion revascularization was also lower in the cutting balloon group [29% (8/27) vs 53% (16/30) p=0.05]. In group 1, the MLD of the parent vessel did not change before, after cutting balloon or at follow-up. In contrast, there were significant reductions in parent vessel MLD following stenting alone and at follow-up. Plaque shift did not occur in the cutting balloon group. Cutting balloon angioplasty is a feasible approach for the treatment of small branch ostial lesions and does not cause significant narrowing of the parent vessel.     

Six-month outcome after excimer laser coronary angioplasty for diffuse in-stent restenosis in native coronary arteries

This study evaluated the intermediate-term follow-up after excimer laser coronary angioplasty (ELCA) and adjunctive percutaneous transluminal coronary angioplasty (PTCA) in patients with diffuse in-stent restenosis (lesion length >10 mm). Clinical and angiographic follow-up were performed at 6 months. Quantitative coronary angiography performed at 3 stages-during stent implantation, before and after ELCA + PTCA, and at follow-up-included measurements of the minimum lumen diameter (MLD) and percent diameter stenosis (DS). Sixteen consecutive patients were included. The (median + range) stent length was 36 mm (range 15 to 105), with a restenotic lesion length of 32 mm (range 10 to 90). After ELCA + PTCA, the MLD increased from 0.60 +/- 0.41 to 2.28 +/- 0.50 mm, whereas the DS decreased from 76 +/- 16% to 22 +/- 8%. Despite adjunctive high-pressure PTCA, the MLD after ELCA + PTCA remained smaller than the MLD after initial stent implantation, (2.28 +/- 0. 50 mm vs 2.67 +/- 0.32 mm, p = 0.014). Adverse events included ELCA-related acute coronary occlusion in 4 patients and a per-procedural intracerebral hematoma in 1. At 6 months, there was recurrence of angina in all patients. Angiographic follow-up was completed in 13 patients (87%), showing a reocclusion in 6 (46%), a >50% DS in 6 (MLD 1.03 +/- 0.87 mm, DS 68 +/- 24%), and a distal de novo lesion in 1. Despite satisfactory acute angiographic results, the recurrence of significant restenosis in all patients suggests that ELCA + PTCA is not a suitable stand-alone therapy for diffuse in-stent restenosis of long stented segments.     

Determining appropriate small vessels for stenting by intravascular ultrasound

To re-evaluate outcomes of stenting in small vessels, we studied 176 patients successfully treated with several types of stent by way of intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA). These lesions were divided into 3 subgroups according to reference diameter (RD) by QCA, and vessel diameter (VD) by IVUS (group I: pre-RD 2.5 mm; group II: pre-RD < 2.5 mm and pre-VD 4.0 mm; group III: pre-RD < 2.5 mm and pre-VD < 4.0 mm). Post-procedure percent diameter stenosis (4 +/- 3%), post-procedure percent plaque area (42 +/- 3%), and loss index (39 +/- 11%) in group II were not significantly different from those in group I (7 +/- 2%, 37 +/- 2%, 45 +/- 5%, respectively). The rates of restenosis and target lesion revascularization in group II (24.0% and 16.0%, respectively) were not different from those in group I (25.9% and 21. 2%, respectively), and were significantly favorable compared to group III (66.7% and 39.4%, respectively; p < 0.05). By the use of IVUS, we not only identified those vessels which would normally go unstented when only using QCA, but also documented excellent long-term outcome in these patients.     

Effects of beta-radiation using a holmium-166 coated balloon on neointimal hyperplasia in a porcine coronary stent restenosis model.

Brachytherapy is a promising method of preventing and treating coronary stent restenosis. The present study was designed to observe the therapeutic effects of a radioactive balloon loaded with Holmium-166 ((166)Ho) in a porcine coronary stent restenosis model. A radioisotope of (166)Ho was coated onto the balloon surface using polyurethane (20 Gy at 0.5 mm depth). Stent overdilation injuries were induced in 2 coronary arteries in each pig (n=8). Four weeks after the injury, control balloon dilation was performed in one coronary artery (Group I) and radiation therapy using the (166)Ho coated balloon in the other coronary artery (Group II) in each pig. Follow-up coronary angiography and histopathologic assessment were performed at 4 weeks after the radiation therapy or the control balloon dilations. With regard to complete blood cell counts, liver function tests, lipid profiles and coagulation tests, there were no differences between the baseline and after radiation. On quantitative coronary angiographic analysis, reference and target artery diameter showed no differences between the 2 groups before, or 4 and 8 weeks after stenting. On histopathologic analysis of groups I and II, the injury score was 1.34+/-0.09 and 1.32+/-0.10, the area of internal elastic lamina was 4.99+/-0.17 mm(2) and 4.82+/-0.20 mm(2), and the luminal area was 3.20+/-0.10 mm(2) and 3.45+/-0.14 mm(2), respectively (p=NS). The neointimal area was 1.78+/-0.11 mm(2) in group I and 1.36+/-0.12 mm(2) in group II (p=0.017), and the histopathologic area of stenosis was 35.1+/-1.6% in group I and 27.6+/-1.9% in group II (p=0.005). In conclusion, beta-radiation of the stented porcine coronary artery using a radioactive (166)Ho coated balloon inhibited stent restenosis without any side effects.