Restenosis and stent fracture following sirolimus-eluting stent (SES) implantation.

BACKGROUND: Restenosis still occurs, even with the sirolimus-eluting stent (SES), and the precise mechanisms and the impact of stent fracture on restensosis have not yet been elucidated. METHODS AND RESULTS: Intravascular ultrasound (IVUS)-guided SES implantation was performed in 184 lesions in 151 patients with stable and unstable angina. Serial (pre-, post- and follow-up) quantitative coronary angiography analysis was obtained in 169 lesions in 138 patients (angiographic follow-up rate: 91%) and 12-month clinical follow-up was done in all patients. Restenosis occurred in 13 (7.7%) of 169 lesions. Stent fracture occurred in 4 (2.4%) of 169 lesions at follow-up. Of the 13 restenotic lesions, 8 had intimal hyperplasia, 4 had stent fracture, and 1 had late stent thrombosis at 7 months. Although multivariate logistic regression analysis revealed that minimal lumen area (min-LA) post (p=0.027), total stent length (p=0.003) and diabetes (p=0.032) were significant independent predictors of restenosis, univariate analysis showed that stent fracture was more common in the restenosis than in the non-restenosis groups (p=0.001). CONCLUSIONS: Although min-LA post by IVUS, total stent length by QCA and diabetes are independent predictors for angiographic restenosis, stent fracture occurred in 4 lesions (2.4%) and all of them resulted in restenosis (31% of the restenosis). The impact of stent fracture and its potential role in the development of restenosis deserves further study.     

Intravascular Ultrasound Predictors of Angiographic Restenosis in Lesions Treated With Palmaz-Schatz Stents

Objectives. This study sought to evaluate the clinical, procedural, preinterventional and postinterventional quantitative coronary angiographic (QCA) and intravascular ultrasound (IVUS) predictors of restenosis after Palmaz-Schatz stent placement.Background. Although Palmaz-Schatz stent placement reduces restenosis compared with balloon angioplasty, in-stent restenosis remains a major clinical problem.Methods. QCA and IVUS studies were performed before and after intervention (after stent placement and high pressure adjunct balloon angioplasty) in 382 lesions in 291 patients treated with 476 Palmaz-Schatz stents for whom follow-up QCA data were available 5.5 ± 4.8 months (mean ± SD) later. Univariate and multivariate predictors of QCA restenosis (≥50% diameter stenosis at follow-up, follow-up percent diameter stenosis [DS] and follow-up minimal lumen diameter [MLD]) were determined.Results. Three variables were the most consistent predictors of the follow-up angiographic findings: ostial lesion location, IVUS preinterventional lesion site plaque burden (plaque/total arterial area) and IVUS assessment of final lumen dimensions (whether final lumen area or final MLD). All three variables predicted both the primary (binary restenosis) and secondary (follow-up MLD and follow-up DS) end points. In addition, a number of variables predicted one or more but not all the end points: 1) restenosis (IVUS preinterventional lumen and arterial area); 2) follow-up DS (QCA lesion length); and 3) follow-up MLD (QCA lesion length and preinterventional MLD and DS and IVUS preinterventional lumen and arterial area).Conclusions. Ostial lesion location and IVUS preinterventional plaque burden and postinterventional lumen dimensions were the most consistent predictors of angiographic in-stent restenosis.     

Optimal final lumen area and predictors of target lesion revascularization after stent implantation in small coronary arteries

Despite similar early clinical events, patients who undergo treatment of small vessels are at an increased risk for target lesion revascularization (TLR) after coronary artery stenting. We sought to determine predictors of TLR after stent implantation in small coronary arteries. We identified 423 consecutive patients who underwent intravascular ultrasound (IVUS)-guided small vessel stenting procedures in 465 coronary lesions with an angiographic reference vessel diameter of <2.75 mm. Patients were divided into 2 groups based on a final IVUS lumen area of < or =6.0 mm2 (n=345 lesions, group I) and >6.0 mm2 (n=115, group II). Baseline patient characteristics and in-hospital outcomes were similar between the 2 groups, except for a higher rate of restenotic lesions in group I and bifurcation lesions in group II. Group I had higher TLR rates at 1 year compared with group II patients (39% vs 26%, p = 0.02). The TLR rate appeared to decrease with greater stent expansion, especially at >90% of the reference vessel area, as assessed by IVUS. By multivariate analysis, an IVUS final stent area of < or =6 mm2, diabetes, absence of prior myocardial infarction, and history of intervention were independent predictors of 1-year TLR in this population. Final stent area of >6.0 mm2 and greater stent expansion were associated with a decrease in TLR. Therefore, there does not appear to be any "downside" to aggressive stent implantation strategies in small vessels. In contrast, IVUS allows maximization of final lumen dimensions to minimize clinical restenosis.     

Intravascular ultrasonic predictors of angiographic restenosis after long coronary stenting

The intravascular ultrasound (IVUS) criteria for stent optimization have not been determined in stenting long lesions. We evaluated the predictors of angiographic restenosis and compared it with stent lumen cross-sectional area (CSA) and stent length between short (stent length <20 mm) and long (> or =20 mm) coronary stenting. IVUS-guided coronary stenting was successfully performed in 285 consecutive patients with 304 native coronary lesions. Six-month follow-up angiogram was performed in 236 patients (82.8%) with 246 lesions (80.9%). Results were evaluated using conventional (clinical, angiographic, and IVUS) methods. The overall angiographic restenosis rate was 22.8% (56 of 246 lesions) (short stent 17.6% vs. long stent 32.2%, p = 0.009). Using multivariate logistic regression analysis, the independent predictors of angiographic restenosis were the IVUS stent lumen CSA (odds ratio 1.51, 95% confidence intervals 1.18 to 1.92, p = 0.001) and stent length (odds ratio 0.95, 95% confidence intervals 0.91 to 1.00, p = 0.039). The angiographic restenosis rate was 54.8% for stent lumen CSA of <5.0 mm2 (short stent 37.5% vs. long stent 73.3%, p = 0.049), 27.4% for CSA between 5.0 and 7.0 mm2 (short stent 24.1% vs. long stent 31.7%, p = 0.409), 10.5% for CSA between 7.0 and 9.0 mm2 (short stent 10.0% vs. long stent 12.5%, p = 0.772), and 11.4% for stent lumen CSA of > or =9.0 mm2 (short stent 10.4% vs. long stent 13.3%, p = 0.767) (p = 0.001). Compared with short coronary stenting, long coronary stenting is effective treatment modality to cover long lesions with comparable long-term clinical outcomes in cases of stent lumen CSA of > or =7.0 mm2. Regardless of the stent length, the most important factor determining angiographic restenosis was the IVUS stent lumen CSA in relatively large coronary artery lesions.     

Angiographic and intravascular ultrasound predictors of in-stent restenosis

Objectives. This study was performed to determine predictors of in-stent restenosis from a high volume, single-center practice.Background. Intracoronary stents have been shown to reduce the restenosis rate as compared with balloon angioplasty, but in-stent restenosis continues to be an important clinical problem.Methods. Between April 1993 and March 1997, 1,706 patients with 2,343 lesions were treated with a variety of intracoronary stents. The majority of stents were placed with high pressure balloon inflations and intravascular ultrasound (IVUS) guidance. Angiographic follow-up was obtained in 1,173 patients with 1,633 lesions (70%). Clinical, angiographic and IVUS variables were prospectively recorded and analyzed by univariate and multivariate models for the ability to predict the occurrence of in-stent restenosis defined as a diameter stenosis ≥50%.Results. In-stent restenosis was angiographically documented in 282 patients with 409 lesions (25%). The restenosis group had a significantly longer total stent length, smaller reference lumen diameter, smaller final minimal lumen diameter (MLD) by angiography and smaller stent lumen cross-sectional area (CSA) by IVUS. In lesions where IVUS guidance was used, the restenosis rate was 24% as compared with 29% if IVUS was not used (p < 0.05). By multivariate logistic regression analysis, longer total stent length, smaller reference lumen diameter and smaller final MLD were strong predictors of in-stent restenosis. In lesions with IVUS guidance, IVUS stent lumen CSA was a better independent predictor than the angiographic measurements.Conclusions. Achieving an optimal stent lumen CSA by using IVUS guidance during the procedure and minimizing the total stent length may reduce in-stent restenosis.     

Primary and mid-term outcome of sirolimus-eluting stent implantation with angiographic guidance alone

BACKGROUND: Usefulness and efficacy of intravascular ultrasound (IVUS) for the implantation of sirolimus-eluting stent (SES) is controversial. We investigated the primary and mid-term results of SES deployment with angiographic guidance comparing with IVUS guidance, retrospectively. METHODS AND RESULTS: SESs were deployed in 480 de novo lesions of 459 patients (341 lesions treated without IVUS and 139 lesions treated using IVUS); 368 lesions underwent follow-up coronary angiography. Late luminal loss, in-stent restenosis (ISR) rate and target lesion revascularization (TLR) rate were not significantly different between the non-IVUS group and the IVUS group. There was no acute thrombosis or other major adverse cardiac events except for TLR in both groups. Multivariate logistic regression analysis showed that SES implantation without IVUS was not an independent risk factor for restenosis. On the other hand, in one case, target-vessel revascularization was difficult because of the mal-apposition of the SES previously implanted without IVUS. CONCLUSIONS: For lesions for which stent size and endpoint are decided from angiographic information alone, angio-guided SES implantation is safe and provides a good mid-term outcome that is comparable to the IVUS-guided SES stent deployment., while IVUS may be helpful to decide stent size for complex lesions and reduce possible complications.     

Usefulness of minimum stent cross sectional area as a predictor of angiographic restenosis after primary percutaneous coronary intervention in acute myocardial infarction (from the HORIZONS-AMI Trial IVUS substudy)

HORIZONS-AMI was a prospective dual-arm randomized trial of different antithrombotic regimens and stent types in patients with ST-segment elevation myocardial infarction. A formal intravascular ultrasound (IVUS) substudy enrolled 464 patients with baseline and 13-month follow-up at 36 centers. Of them, 318 patients with 355 lesions were evaluated for this study. Angiographic restenosis occurred in 45 of 355 lesions (12.7%). Bare-metal stent use (45.5% vs 21.2%, p <0.001) and diabetes mellitus (29.5% vs 10.9%, p <0.001) were more prevalent in patients with versus without restenosis. Postprocedure IVUS minimum lumen area (5.6 mm(2), 5.0 to 6.1, vs 6.7 mm(2), 6.5 to 6.9, p <0.001), minimum stent area (5.7 mm(2), 5.1 to 6.3, vs 6.9 mm(2), 6.6 to 7.1, p <0.001), and reference average lumen area (7.7 mm(2), 6.8 to 8.6, vs 9.7 mm(2), 9.3 to 10.1, p <0.001) were smaller in restenotic versus nonrestenotic lesions. By multivariable analysis, minimum stent area was an independent predictor of angiographic restenosis (odds ratio 0.75, 95% confidence interval 0.61 to 0.93, p = 0.009) in addition to diabetes, bare-metal stent use, and longer stent length. Attenuated plaque behind the stent struts had a trend to predict less binary restenosis (p = 0.07). In conclusion, a smaller IVUS minimum stent area was an independent predictor of angiographic restenosis after primary percutaneous intervention in patients with ST-segment elevation myocardial infarction, similar to patients with stable coronary artery disease.     

Sirolimus-eluting stent for treatment of complex in-stent restenosis: the first clinical experience

OBJECTIVES: In this study, we assess the value of sirolimus eluting stent (SES) implantation in patients with complex in-stent restenosis (ISR). BACKGROUND: The treatment of ISR remains a therapeutic challenge, since many pharmacological and mechanical approaches have shown disappointing results. The SESs have been reported to be effective in de-novo coronary lesions. METHODS: Sixteen patients with severe, recurrent ISR in a native coronary artery (average lesion length 18.4 mm) and objective evidence of ischemia were included. They received one or more 18 mm Bx VELOCITY SESs (Cordis Waterloo, Belgium). Quantitative angiographic and three-dimensional intravascular ultrasound (IVUS) follow-up was performed at four months, and clinical follow-up at nine months. RESULTS: The SES implantation (n = 26) was successful in all 16 patients. Four patients had recurrent restenosis following brachytherapy, and three patients had totally occluded vessels preprocedure. At four months follow-up, one patient had died and three patients had angiographic evidence of restenosis (one in-stent and two in-lesion). In-stent late lumen loss averaged 0.21 mm and the volume obstruction of the stent by IVUS was 1.1%. At nine months clinical follow-up, three patients had experienced four major adverse cardiac events (two deaths and one acute myocardial infarction necessitating repeat target vessel angioplasty). CONCLUSIONS: The SES implantation in patients with severe ISR lesions effectively prevents neointima formation and recurrent restenosis at four months angiographic follow-up.     

血管内超声评价雷帕霉素洗脱支架再狭窄及早期血栓形成

目的 以血管内超声评价雷帕霉素洗脱支架置人术后发生支架内再狭窄及血栓形成的机械性危险因素.方法 对雷帕霉素洗脱支架置入术后发生支架内再狭窄或早期(≤30 d)血栓形成的60例患者(事件组)及无支架内再狭窄和早期血栓形成的34例患者(无事件组)的血管内超声资料进行分析比较.结果 事件组发生支架内再狭窄43例,早期血栓形成17例.与无事件组比较,事件组的最小支架面积(MSA)[(4.6±1.6)mm2比(5.8±1.6)mm2,P＜0.01]、最小支架直径[(2.2±0.5)mm比(2.5±0.4)mm,P＜0.01]和支架扩张率[(69.2±20.7)%比(80.6±17.2)%,P＜0.01]较小、纵向支架对称性较差(2.0±0.6比1.7±0.6,P＜0.05).MSA＜4 mm2(43.3%比14.7%,P＜0.01)和支架扩张率＜60%(40.7%比11.8%,P＜0.01)在事件组较常见.与无事件组比较,事件组的近段残余斑块负倚较大[(49.0±15.5)%比(38.4±17.6)%,P＜0.01].Logistic回归分析显示,MSA(OR:0.7,95%CI:0.5～0.8,P＜0.01)和近段残余斑块负荷(OR:280.7,95%CI:17.2～40 583.6,P＜0.01)是药物洗脱支架发生再狭窄或早期血栓形成的独立预测因素.结论 较小的MSA和较重的近段残余病变易导致雷帕霉素洗脱支架发生支架内冉狭窄及早期血栓形成.     

Impact of vessel size, lesion length and diabetes mellitus on angiographic restenosis outcomes: insights from the NIRTOP study

BACKGROUND: The primary objective of the current analysis was to define the impact of vessel size, lesion length, and diabetes on clinical and angiographic restenosis following implantation of the NIRFLEX stent. METHODS AND RESULTS: Clinical and angiographic restenosis outcomes and multivariate predictors were compared between patients treated in 'small' (<3 mm, n=113 pts/133 lesions) versus 'large' (> or =3 mm, n=41 pts/53 lesions) vessels; between 'tubular' (10-20 mm lesion length n=49 pts/51 lesions) versus 'discrete' (<10 mm lesion length n=103 pts/133 lesions) lesions; and between 'diabetic' (n=30/35 lesions) versus 'non-diabetic' (n=128/156 lesions) patients using the flexible closed-cell design 'bare-metal' NIRFLEX stent in patients with native coronary artery disease. At six month follow-up, target vessel revascularization (TVR) and target lesion revascularization (TLR) rates were significantly less frequent in the 'large' versus 'small' vessel group (2.4% versus 16.8% for TVR, P=0.016, 0% versus 12.4% for TLR, P=0.022). Likewise, angiographic late loss was lower in 'large' versus 'small' vessels (0.54 versus 0.70 mm, P=0.05). Lesion length affected MACE rates but not angiographic restenosis. Angiographic late loss was greater in diabetics compared to the non-diabetic group (0.89 versus 0.60 mm, P=0.003). Using a multivariate model, diabetes mellitus (odds ratio=2.65, P=0.047) and post-procedure in-stent MLD (mm) (odds ratio=0.178, P=0.0019) were major determinants of restenosis. CONCLUSION: Clinical and angiographic restenosis outcomes following NIRFLEX stent implantation were dependent upon vessel size, lesions length, post-procedural stent lumen dimensions, and the diabetic status.     

Intravascular ultrasound assessment of lesions with target vessel failure after sirolimus-eluting stent implantation

Intravascular ultrasound (IVUS) evaluation was performed in 33 lesions with sirolimus-eluting stent (SES) failure: 4 thromboses, 26 in-stent restenoses (including 6 edge stenoses), 4 new stenoses >5 mm proximal to the stent, and 1 patient with no evidence of the implanted SES (presumably because of embolization). A minimum stent area <5.0 mm(2) (stent underexpansion) was observed in 67% of all SES failures (in particular, 67% of intrastent restenosis); negative remodeling was observed in 4 of 6 stent edge restenoses, and new lesions were secondary to an increase in plaque area.     

Relation between residual plaque burden after stenting and six-month angiographic restenosis

The degree of residual plaque burden outside of a stent might be correlated with the degree of intimal hyperplasia. However, the relation between residual plaque burden and angiographic restenosis are still unknown in a large number of patients. Therefore, we evaluated the effect of residual plaque burden after stenting on 6-month angiographic restenosis. Intravascular ultrasound (IVUS)-guided coronary stenting was successfully performed in 723 patients with 785 native coronary lesions. Six-month follow-up angiograms and evaluation of residual plaque burden by IVUS were available in 566 patients (78.3%) with 622 lesions (79.2%). Results were evaluated using conventional methods. The overall angiographic restenosis rate was 23.0% (143 of 622 lesions). There was no significant difference in residual plaque burden between the lesions with and without restenosis (52% vs 51%, respectively, p = 0.148). The angiographic restenosis rate was 20.8% (11 of 53 lesions), 21.6% (51 of 236 lesions), 22.0% (55 of 250 lesions), and 31.3% (26 of 83 lesions) in the lesions with residual plaque burden < 40%, between 40% and 50%, between 50% and 60%, and > 60%, respectively (p = 0.284). Using multivariate logistic regression analysis, the only independent predictor of angiographic restenosis was the IVUS stent area (odds ratio 0.807, 95% confidence intervals 0.69 to 0.95, p = 0.011). Furthermore, even in the lesions with residual plaque burden > 60%, the restenosis rate was 37.3% (23 of 61 lesions) versus 13.6% (3 of 22 lesions ) in IVUS stent areas of < 7 and > or =7 mm(2), respectively (p = 0.031). In conclusion, residual plaque burden outside the stent might not predict angiographic restenosis. IVUS stent area was the only independent predictor of angiographic restenosis.     

The incidence and predictors of postprocedural incomplete stent apposition after angiographically successful drug‐eluting stent implantation

Objectives: The aim of this study was to evaluate the incidence and predictors of postprocedural incomplete stent apposition (ISA) after angiographically successful drug‐eluting stent (DES) implantation. Background: The deployed stents are usually evaluated by angiography alone; however, there are possibilities of postprocedural ISA despite the angiographically successful implantation. Methods: A total of 339 lesions in which poststent intravascular ultrasound (IVUS) was performed after successful DES implantation was included. Paclitaxel‐eluting stents were implanted in 237 lesions and sirolimus‐eluting stents (SES) in 102 lesions. Clinical, angiographic and procedural characteristics and IVUS findings for all cases were analyzed. Results: The overall incidence of ISA was 13.9% (47/339). By multivariate analysis, male gender (OR: 2.36, 95% CI: 1.09–5.11), deployment of SES (OR: 2.90, 95% CI: 1.49–5.67), the presence of intracoronary thrombus (OR: 7.47, 95% CI: 1.67–33.47), and non‐ST elevation myocardial infarction (OR: 2.73, 95% CI: 1.09–6.83) were independent predictors for postprocedural ISA after angiographically successful DES implantation. Conclusions: The incidence of postprocedural ISA after angiographically successful implantation of DES was not infrequent. A DES deployment strategy incorporating IVUS guidance might be helpful to reduce the incidence of postprocedural ISA. © 2009 Wiley‐Liss, Inc.     

Comparison of vessel response following sirolimus-eluting stent implantation as assessed by serial 3-D intravascular ultrasound study

Recent sirolimus-eluting stent (SES) studies have suggested higher rates of restenosis in non-left anterior descending (LAD) artery lesions. The aim of this study was to evaluate differential vessel response (LAD versus non-LAD) to SES implantation using serial intravascular ultrasound (IVUS). A total of 94 patients who underwent SES implantation and serial (post-PCI and 8 months) 3-dimensional IVUS were enrolled from our database. Volumetric analysis was performed throughout the stent as well as the adjacent reference segment (up to 5 mm). Volume index (volume/length) was calculated for vessel (VVI), lumen (LVI), and plaque (PVI). Cross-sectional narrowing (CSN) was defined as neointimal area divided by stent area (%). With respect to the in-stent segment, VVI, PVI, and LVI at post-PCI were not significantly different between the LAD (n = 41) and non-LAD (n = 53) lesions. At follow up, however, maximum CSN was significantly greater in the non-LAD lesions (18.3 +/- 15.2% versus 12.2 +/- 10.0%; p = 0.029). At the proximal reference segment, the non-LAD lesions showed a significantly greater LVI decrease than the LAD lesions (p <0.05), primarily due to mild vessel shrinkage observed in the non-LAD lesions. There were no significant differences at the distal reference segment between the LAD and non-LAD lesions. This detailed IVUS analysis suggests that there are minimal differences in the vessel responses following SES implantation. These findings may have potential implications for mechanical and pharmacokinetic properties of next-generation drug-eluting stent technology.     

Vascular response to sirolimus-eluting stents delivered with a nonaggressive implantation technique: comparison of intravascular ultrasound results from the multicenter, randomized E-SIRIUS, and SIRIUS trials.

BACKGROUND: The effectiveness of SES to reduce the risk of restenosis was initially demonstrated in short lesions using stent implantation with routine pre-dilatation and post-dilatation. This intravascular ultrasound (IVUS) substudy of the E-SIRIUS trial sought to evaluate local arterial responses to sirolimus-eluting stents (SES) delivered with a stent implantation technique allowing direct stenting and only selectively applying high-pressure post-dilatation. METHODS AND RESULTS: IVUS was performed immediately after intervention and at 8-month follow-up in 51 patients randomised to either bare-metal stents (BMS; Bx-Velocitytrade mark; N=20) or SES (Cyphertrade mark N=31). Direct stenting was allowed (24%) and post-dilation was performed only selectively (32%). Lumen dimensions, intimal hyperplasia and vessel remodeling were compared between SES and BMS. Subsequently, results of SES in the E-SIRIUS IVUS substudy (N=31) were compared to those of SES in the IVUS substudy of the SIRIUS trial (N=137). SES in SIRIUS IVUS substudy were delivered with 100% pre-dilatation and 77% post-dilatation. Baseline stent and reference segment measurements were similar between BMS and SES in E-SIRIUS IVUS patients. Using SES there was a 96% reduction in intimal hyperplasia volume within the stented segment (1.8+/-4.9 vs 50.6+/-39.7 mm3, P<0.001) and a significantly larger minimal lumen cross sectional area at 8-month follow-up (4.5+/-1.1 vs 2.3+/-0.9 mm2, P<0.001). No vessel remodeling was observed with the use of SES. The applied stent implantation technique resulted in a minimal stent/reference vessel area ratio of 0.75+/-0.17 in E-SIRIUS SES as compared to 0.84+/-0.23 in SIRIUS SES (P=0.046). Mean intimal hyperplasia cross-sectional area at follow-up was 0.1+/-0.2 mm2 in the SES group of E-SIRIUS and 0.5+/-0.8 mm2 in the SES group of SIRIUS (P=0.003). CONCLUSIONS: An implantation technique of SES which includes direct stenting and minimizes the use of high-pressure post-dilatation results in less optimal stent expansion. However, follow-up results compare very favourable to those of BMS and are characterised by even less intimal hyperplasia than after a more forceful implantation of SES.     

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.     

Intravascular ultrasound assessment of expansion of the sirolimus-eluting (cypher select) and paclitaxel-eluting (Taxus Express-2) stent in patients with diabetes mellitus

Patients with diabetes have a higher risk for in-stent restenosis after coronary stent implantation. Drug-eluting stents (DES) are highly effective in reducing in-stent restenosis. Once neointimal hyperplasia is suppressed with DES, the impact of stent underexpansion becomes magnified. The aim of this study was to evaluate DES expansion in patients with diabetes. Ninety-five patients with diabetes were randomized to Cypher Select (n = 48) or Taxus Express-2 (n = 47) stent implantation. Intravascular ultrasound was performed after stent implantation. Stent expansion was defined as the ratio of measured to predicted minimum stent diameter. There was a trend for lower stent expansion in the Cypher Select stent group (0.74 +/- 0.08 vs 0.78 +/- 0.11 in the Taxus Express-2 stent group, p = 0.061). Cypher Select stents achieved a final minimal stent cross-sectional area of 5.5 +/- 1. 8 mm2, compared with 6.4 +/- 1.9 mm2 for Taxus Express-2 stents (p = 0.015). For stents with nominal diameters > or =2.75 mm (Cypher Select n = 40, Taxus Express-2 n = 38), 42.5% of the Cypher Select stents and 10.5% of the Taxus Express-2 stents did not achieve a final minimum stent area of 5 mm2 (p = 0.002). Insulin treatment (relative risk 0.31, 95% confidence interval 0.10 to 0.95, p = 0.041) and stent type (relative risk 0.15, 95% CI 0.04 to 0.53, p = 0.003) were independent predictors of not achieving a minimum stent area >5.0 mm2. In conclusion, an important percentage of DES in patients with diabetes fail to achieve the manufacturers' predicted final minimal stent diameter. Cypher Select stent and insulin treatment were independent predictors of not achieving a minimum stent area >5.0 mm2.     

Late target lesion revascularization after implantation of sirolimus‐eluting stent

Objectives : We evaluated the incidence, clinical presentation, and angiographic in‐stent restenosis (ISR) pattern of late target lesion revascularization (TLR) after sirolimus‐eluting stent (SES) implantation. Background : Late TLR is an unusual finding beyond 6–9 months after bare‐metal stent implantation. However, late TLR after SES implantation has not been sufficiently evaluated. Methods : The study population consisted of 804 patients with 1,020 native lesions that were patent at 6‐month follow‐up angiogram after SES implantation. Results : Late TLR was performed in 18 patients with 18 lesions (1.8%) at 24.1 ± 2.6 months (range; 18–30 months) after SES implantation. Clinical presentation of late TLR patients was silent ischemia in eight patients and recurrent angina in 10 patients, but none had an acute coronary syndrome. Angiographic ISR pattern of late TLR lesions were focal ISR in 12 lesions (67%) and diffuse ISR in six lesions (33%). Serial quantitative coronary angiographic analysis of these lesions showed a minimal lumen diameter of 2.6 ± 0.5 mm immediately after SES implantation, 2.4 ± 0.4 mm at 6‐month follow‐up and 0.7 ± 0.6 mm at 24‐month follow‐up (ANOVA P < 0.001). By stepwise multiple logistic regression analysis, the only independent predictor of late TLR was stent length (P < 0.001, OR = 1.040, 95% CI = 1.019–1.061). Conclusions : Late TLR was performed in 1.8% of 1,020 native lesions that were patent at 6‐month follow‐up angiogram. Clinical presentations of late TLR was either silent ischemia or recurrent angina, but not acute coronary syndrome. Two‐thirds of late TLR lesions had a focal angiographic ISR pattern. © 2007 Wiley‐Liss, Inc.     

Six-month angiographic follow-up after intravascular ultrasound-guided stenting of infarct-related artery: comparison with non-infarct-related artery

BACKGROUND: Compared with balloon angioplasty, stenting has been established as an effective treatment modality to reduce restenosis in patients with acute myocardial infarction. However, the immediate results that predict favorable long-term outcomes in the acute infarct stenting are unknown. Therefore, we evaluated long-term outcomes of stenting for infarct-related artery (IRA) lesions by using intravascular ultrasound (IVUS) compared with that of stenting for non-IRA lesions. METHODS: IVUS-guided coronary stenting was successfully performed in 510 native coronary lesions (105 IRA vs 405 non-IRA). A 6-month follow-up angiogram was performed in 419 (82.2%) lesions: 87 (82.9%) IRA lesions and 332 (82.0%) non-IRA lesions. Coronary stenting on the IRA lesions was successfully performed within 7 to 10 days after onset of infarction in 42 patients and within 12 hours in 45 patients. Results were evaluated by clinical, angiographic, and IVUS methods. RESULTS: There were no significant differences in clinical and angiographic variables between the two groups. IVUS variables including reference vessel area and minimal stent area were also similar between the two groups. There was no significant difference in angiographic restenosis rate between the two groups in cases of minimal stent area > or = 7 mm(2): 12.8% (6 of 47) in IRA versus 19.1% (33 of 173) in non-IRA lesions (P = .315). However, the angiographic restenosis rate in cases of minimal stent area <7 mm(2) was 50% (20 of 40) in IRA lesions versus 31.5% (50 of 159) in non-IRA lesions (P = .028). CONCLUSIONS: Angiographic restenosis is significantly higher in stenting for IRA lesions compared with that for non-IRA lesions in cases of minimal stent area < 7 mm(2).     

Impact of intravascular ultrasound findings on long-term patency after self-expanding nitinol stent implantation in the iliac artery lesion

Although intravascular ultrasound (IVUS) predictors of stent patency for the coronary artery lesion have been established, little is known about IVUS predictors of stent patency for the aorto-iliac artery lesion. We analyzed 154 lesions of 122 patients who underwent stent implantation for iliac artery lesions. Quantitative and qualitative IVUS analyses were performed for pre- and post-procedural IVUS imaging in all lesions. Target lesion revascularization (TLR) was defined as clinically driven revascularization with >50 % angiographic stenosis of the target lesion. The mean follow-up period was 39 ± 16 months. TLRs were performed in 13 lesions (8.4 %). Post-procedural minimum stent area (MSA) was significantly smaller in the TLR group compared to the no-TLR group (16.0 ± 5.8 vs. 25.6 ± 8.5 mm², p < 0.001). Stent edge dissection was frequently observed in the TLR group compared to the no-TLR group (53.8 vs. 24.1 %, p = 0.04). Multivariate analysis revealed that post-procedural MSA (OR = 0.76, p < 0.01) and stent edge dissection (OR = 10.4, p < 0.01) were independent IVUS predictors of TLR. Receiver-operating characteristic analysis identified post-procedural MSA <17.8 mm² as the optimal cut-point for the prediction of TLR (AUC = 0.846). Post-procedural MSA and stent edge dissection could predict long-term stent patency in the iliac artery lesion. Our results propose that adequate stent enlargement without edge dissection might be important to reduce TLR in the iliac artery lesion.