Two-year follow-up intravascular ultrasound analysis after bare metal stent implantation in 120 lesions.

The objective of this study was to examine long-term changes after bare metal stent implantation in a relatively large number of patients. There are few reports of intravascular ultrasound (IVUS) studies performed on stented and nonstented (reference) segments beyond 6 months after bare metal stenting. Using IVUS, we evaluated serial changes in stented and reference segments between 6 and 24 months after stent implantation in 110 patients with 120 lesions. Serial IVUS images were acquired at five equidistant intrastent sites and at two different reference segment sites. Measurements were made of the external elastic membrane (EEM), stent, lumen, and intimal hyperplasia (IH = stent - lumen) area. For the whole patient group, between 6 and 24 months, the mean IH area in stented segments decreased from 2.6 +/- 1.0 to 2.3 36+/- 0.9 mm2 (P < 0.001), and the mean lumen area increased from 6.2 +/- 2.0 to 6.5 +/- 1.9 mm2 (P < 0.001). The mean IH area decreased in 91 lesions (76%) and increased in 29 lesions (24%) between 6 and 24 months. There were no significant changes in EEM or lumen area in the reference segments. Late angiographic restenosis (diameter stenosis > or = 50%) occurred in three lesions between 6 and 24 months. A late target lesion revascularization was performed for one lesion. In the period of time between 6 and 24 months after stenting, IH regression occurred in most (76%) stent lesions, resulting in late lumen increase. However, IH progression was observed in 24% of in-stent lesions. No significant changes of EEM or lumen area occurred in the reference segments.     

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.     

Characterization of plaque prolapse after drug-eluting stent implantation in diabetic patients: a three-dimensional volumetric intravascular ultrasound outcome study.

OBJECTIVES: The aim of this research was to evaluate the plaque prolapse (PP) phenomenon after bare-metal (BMS) and drug-eluting stent (DES) implantation in patients with diabetes mellitus using 3-dimensional volumetric intravascular ultrasound (IVUS). BACKGROUND: Plaque prolapse has been observed in up to 22% of patients treated with BMS. Diabetic patients have a larger atherothrombotic burden and may be more prone to have PP. However, the incidence of PP and its clinical impact after DES implantation is unknown. METHODS: Three-dimensional IVUS was performed after intervention and at 9-month follow-up in 168 patients with diabetes (205 lesions) treated with bare BX Velocity stents ((BX Velocity/Sonic, Cordis, Johnson & Johnson) (BMS, n = 65), sirolimus-eluting stents (Cypher, Cordis) (SES, n = 69), and paclitaxel-eluting stents (Taxus, Boston Scientific, Natick, Massachusetts) (PES, n = 71). Intravascular ultrasound data at the sites of PP were compared with stented segments without PP in each lesion. Outcomes were evaluated at 9- and 12-month follow-up. RESULTS: There were 42 sites of PP (BMS = 11, SES = 11, PES = 20, p = NS) in 34 stented segments of 205 (16.6%) lesions. Plaque prolapse was more frequent in the right coronary artery and in chronic total occlusion lesions. Post-procedure PP volume was 1.95 mm3 in BMS, 2.96 mm3 in SES, and 4.53 mm3 in PES. At follow-up, tissue volume increased at PP sites in both BMS and PES, but not after SES. Neointimal proliferation was similar between PP and non-PP sites. Stent thrombosis and restenosis rates were similar between PP and non-PP lesions. CONCLUSIONS: The incidence of PP after implantation of new generation tubular stents in patients with diabetes remains high. Drug-eluting stent implantation was not associated with increased risk of PP. Plaque prolapse was not associated with stent thrombosis or increased neointimal proliferation.     

Late intravascular ultrasound findings of patients treated with brachytherapy for diffuse in-stent restenosis.

This study aimed at evaluating long-term (24-month) effects of beta-irradiation (188Re-MAG3-filled balloon) using intravascular ultrasound (IVUS) in patients with in-stent restenosis (ISR). Long-term effects of beta-irradiation on intimal hyperplasia (IH) within the stented segment and vessel and lumen dimensions of nonstented adjacent segments in patients with ISR have not been sufficiently evaluated. Two-year follow-up IVUS was performed in 30 patients with patent ISR segments at 6-month follow-up angiography. Serial IVUS images were acquired at five equidistant intrastent sites and at three different reference segment sites. IH burden (%) was defined as 100 x (IH/stent area). Mean intrastent IH area and IH burden significantly increased between 6 and 24 months, from 2.1 +/- 1.1 to 2.6 +/- 1.4 mm2 (P < 0.001) and from 26% +/- 10% to 33% +/- 14% (P < 0.001), respectively. There was a significant decrease of mean external elastic membrane (from 10.1 +/- 3.9 to 9.7 +/- 3.9 mm2; P = 0.015) and lumen area (from 5.6 +/- 2.3 to 5.1 +/- 2.3 mm2; P = 0.021) within distal reference segments between 6 and 24 months. Target lesion revascularization (TLR) was performed in six patients (20%) between 6 and 24 months after beta-irradiation therapy. There were no significant differences between TLR and non-TLR groups except for a smaller minimum lumen area at 24 months in the TLR group. Because of a small amount of late loss between 6 and 24 months, most irradiated ISR vessel segments remained stable for up to 2 years. However, quantitative evidence of late catch-up was evident in most patients and was significantly associated with 24-month TLR in some patients.     

急性冠状动脉综合征患者雷帕霉素洗脱支架晚期贴壁不良及其对临床预后的影响

目的 观察急性冠状动脉综合征(ACS)患者雷帕霉素洗脱支架晚期贴壁不良发生率及其对临床预后的影响.方法 观察2005年2月至2007年3月因ACS(ACS组,54例)和稳定性心绞痛(对照组,83例)行雷帕霉素洗脱支架治疗并于1年后行血管内超声检查患者,检测支架晚期贴壁不良发生率,并观察血管内超声检查后1年内主要不良心血管事件及支架内血栓发生率.结果 所有137例患者219处病变中,16例患者25处病变检测到晚期支架贴壁不良.25处晚期支架贴壁不良中ACS组和对照组分别为20处(22.2%)和5处(3.9%)(P＜0.001).两组患者参照血管外弹力膜面积、参照血管和支架段血管管腔面积和新生内膜面积均相似,但ACS组患者支架段血管外弹力膜面积[(15.34±5.44)mm2比(13.83±4.51)mm2,P=0.026]、支架段血管外弹力膜面积与参照血管外弹力膜面积比值(1.13±0.22比1.02±0.18,P＜0.001)、斑块和中膜面积[(8.43±3.93)mm2比(7.01±2.93)mm2,P:0.002]较对照组明显增大.Logistic多元回归分析显示,ACS(OR=6.477,P＜0.001)和支架长度≥23 mm(OR=3.680,P=0.025)为晚期支架贴壁不良的独立危险因素.血管内超声检查后临床随访1年,两组主要不良心血管事件发生率差异无统计学意义.结论 雷帕霉素洗脱支架置入后,ACS患者较稳定性心绞痛患者更多发生晚期支架贴壁不良,然而随访1年的主要不良心血管事件发生率差异无统计学意义.     

Volumetric intravascular ultrasound assessment of neointimal hyperplasia and nonuniform stent strut distribution in sirolimus-eluting stent restenosis

The neointimal hyperplasia (IH) distribution pattern of in-stent restenotic lesions after sirolimus-eluting stent (SES) implantation has not been well described. We identified 48 in-stent restenotic lesions (41 patients) after SES implantation and performed volumetric intravascular ultrasound analyses. Lumen area, stent area, and IH area at the minimal lumen area site were 2.7 +/- 1.0, 5.4 +/- 1.9, and 2.7 +/- 1.4 mm(2), respectively. IH area at the minimal lumen site was larger in the group with a stent area > or =5.0 mm(2) than the group with a stent area <5.0 mm(2) (3.7 +/- 1.3 vs 1.9 +/- 0.8 mm(2), p <0.001). There were fewer visualized stent struts in lesions with a minimum stent area > or =5.0 mm(2) at the minimum lumen site compared with those with a stent area <5.0 mm(2) (0.69 +/- 0.25 vs 0.83 +/- 0.16, p = 0.04). When we compared lesions in patients with diabetes mellitus with patients without diabetes, minimum lumen areas, percent IH at minimal lumen area, percent IH, and neointima-free stent length were identical. In conclusion, (1) lesions without SES underexpansion at the minimum lumen site had more IH and greater nonuniform stent strut distribution compared with restenotic SESs that were underexpanded, and (2) the IH response did not appear to be more aggressive in patients with diabetes mellitus than in those without diabetes mellitus.     

Intravascular ultrasound predictors of angiographic restenosis after sirolimus-eluting stent implantation.

AIMS: In many countries, drug-eluting stent implantation is the dominant interventional strategy. We evaluated the clinical, angiographic, procedural, and intravascular ultrasound (IVUS) predictors of angiographic restenosis after sirolimus-eluting stent (SES) implantation. METHODS AND RESULTS: SES implantation was successfully performed in 550 patients with 670 native coronary lesions. Six-month follow-up angiography was performed in 449 patients (81.6%) with 543 lesions (81.1%). Clinical, angiographic, procedural, and IVUS predictors of restenosis were determined. Using multivariable logistic regression analysis, the only independent predictors of angiographic restenosis were post-procedural final minimum stent area by IVUS [odds ratio (OR)=0.586, 95% confidence interval (CI) 0.387-0.888, P=0.012] and IVUS-measured stent length (OR=1.029, 95% CI 1.002-1.056, P=0.035). Final minimum stent area by IVUS and IVUS-measured stent length that best separated restenosis from non-restenosis were 5.5 mm2 and 40 mm, respectively. Lesions with final minimum stent area<5.5 mm2 and stent length>40 mm had the highest rate of angiographic restenosis [17.7% (11/62)], P<0.001 compared with other groups. CONCLUSION: Independent predictors of angiographic restenosis after SES implantation were post-procedural final minimum stent area by IVUS and IVUS-measured stent length. The angiographic restenosis rate was highest in lesions with stent area<5.5 mm2 and stent length>40 mm.     

Heterogeneity of neointimal distribution of in-stent restenosis in patients with diabetes mellitus

Diabetes mellitus is an independent predictor of restenosis after percutaneous coronary intervention. The pattern of restenosis after bare metal stent implantation in diabetic patients was examined with 3-dimensional intravascular ultrasound analysis. Lumen and stent were manually traced at every 0.5-mm interval in stented segments. Using Simpson's method, stent, luminal, and neointimal (stent minus lumen) volumes were calculated and average area was calculated as volume data divided by length. To measure the cross-sectional and longitudinal severities of luminal encroachment by the neointima, percent neointimal area (neointimal area divided by stent area) and neointimal hyperplasia 50 (IH50) (defined as percent stent length with percent neointimal area >50%) were calculated. In 278 patients (68 with diabetes and 210 without diabetes), there was a significantly higher percentage of maximal percent neointimal area with significantly longer percent stent length that was severely encroached by the neointima in diabetic patients. Diabetic patients showed a more heterogenous pattern of the neointima after bare metal stenting, resulting in longer high-grade obstruction segments. This may have important implications for stent design and pharmacokinetic properties of next-generation drug-eluting technology for this complex patient subset.     

Comparison of paclitaxel-eluting stent and sirolimus-eluting stent expansion at incremental delivery pressures

OBJECTIVES: We sought to compare the adequacy of paclitaxel-eluting stent (PES) and sirolimus-eluting stent (SES) expansion based on intravascular ultrasound (IVUS) imaging criteria at conventional delivery pressures. METHODS: Forty-six patients underwent SES implantation and 42 patients underwent PES implantation for de novo native coronary lesions<33 mm in length with reference lumen diameters of 2.5-3.5 mm. Stents were serially expanded with gradual balloon inflations at 14 and 20 atm. IVUS imaging was performed prior to intervention and after each balloon inflation. Stent expansion (minimal stent cross-sectional area/reference lumen cross-sectional area) was measured. Inadequate stent expansion was defined using the MUSIC criteria (all struts apposed, no tissue protrusion, and final lumen cross-sectional area>80% of the reference or >90% if minimal lumen cross-sectional area was <9 mm2). RESULTS: The baseline characteristics of the two groups were similar except for shorter lesion length, larger mean lumen cross-sectional area, larger lumen diameter, and lower plaque burden in the PES group. Stent expansion was inadequate in 80% of patients with SES versus 63% of patients with PES at 14 atm, although this was not statistically significant. After 20 atm, 48% of patients with SES remained underexpanded as compared with 35% of patients with PES. CONCLUSION: Drug-eluting stents showed significant underexpansion by MUSIC criteria at conventionally used inflation pressures. Higher balloon inflations are required especially during deployment of a SES. IVUS guidance is recommended to ensure optimal results and outcomes with both stents.     

IVUS analysis of the acute and long-term stent result using motorized pullback: intraobserver and interobserver variability.

Intravascular ultrasound imaging has become an established method for analysis of intra-coronary stents. We analyzed the reproducibility of morphometric measurements immediately and late after stent implantation and the variability in the selection of predefined sites during motorized catheter pullback. Fifty consecutive patients were investigated immediately and 6 months after Palmaz-Schatz stent implantation (motorized catheter pullback 0.5 mm/sec; 2.9 Fr; 30-MHz transducer). Two experienced investigators independently identified the proximal and distal reference, stent inlet, stent outlet, and the minimal in-stent area in each imaging run. The longitudinal distance between corresponding measurement sites was calculated. Lumen, stent, and vessel area were assessed by planimetry, mean difference was calculated. Long-term reproducibility was analyzed by comparison of measurements made at predefined sites within the stent, immediately and late after implantation. Observer agreement in identification of predefined measurement sites was high. Longitudinal distance between corresponding measurement sites was low and pronounced for the minimal in-stent lumen area. Variabilities for the intra- and interobserver comparison were similar. Values for interobserver comparison were given in brackets. Acute after stent implantation, the variability for the reference proximal was 4.9% (0.4%), distal -1.0% (-4.2%), minimal in-stent lumen -0.5% (1.3%). At follow-up, variability for the reference proximal was -11.0% (-2.2%), distal -1.0% (-2.3%), minimal in-stent lumen 1.9% (6.1%). Long-term reproducibility for the proximal stent inlet was 2.7% (observer 1) and -0.4% (observer 2), for the distal stent outlet 1.3% (observer 1), -3.0% (observer 2), respectively. IVUS investigations with motorized IVUS pullback in stented coronary segments show a low intra- and interobserver variability, both immediately and late after stent implantation. Absolute and relative area differences are low. Long-term reproducibility of measurements within predefined stent sites was high. Motorized catheter pullback guarantees high reliability of IVUS measurements and should be routinely used for clinical IVUS studies.     

Vascular effects of sirolimus-eluting versus bare-metal stents in diabetic patients: three-dimensional ultrasound results of the Diabetes and Sirolimus-Eluting Stent (DIABETES) Trial.

OBJECTIVES: A predefined intravascular ultrasound (IVUS) substudy was performed to evaluate the vascular effects of sirolimus-eluting stent (SES) versus bare-metal stent (BMS). BACKGROUND: The Diabetes and Sirolimus-Eluting Stent (DIABETES) trial is a prospective, multicenter, randomized, controlled trial aimed at demonstrating the efficacy of the SES compared with BMS in diabetic patients. METHODS: Serial intravascular ultrasound analyses were performed in 140 lesions (SES = 75; BMS = 65) immediately after stent implantation and at nine-month follow-up. Vessel, luminal, and stent mean areas and volumes were evaluated at both edges and within the stented segment. Qualitative assessment of residual dissections and stent apposition were also performed. RESULTS: Baseline clinical and angiographic characteristics were similar between groups. At 9 months, in-stent neointimal hyperplasia (NIH) mean area and volume were significantly reduced in the SES group (median NIH area 0.01 mm2 [0.0 to 0.1] vs. 2.0 mm2 [1.0 to 2.9] and median NIH volume 0.11 mm3 [0 to 2.1] vs. 35.3 mm3 [16.6 to 62.6]; both p < 0.0001). In the SES group, stent edges evidenced significant increase in lumen dimensions mainly due to significant increase in vessel volume, whereas those of the BMS group presented vessel shrinkage leading to significant lumen reduction. Late acquired incomplete stent apposition was observed in 11 lesions (14.7%) in the SES group and 0 in the BMS group (p = 0.001). At one year, no stent thromboses occurred in malapposed stents. CONCLUSIONS: The SES implantation effectively inhibits NIH in diabetic patients. The antirestenotic effect of SES is also appreciated at the stent edges. Late acquired stent malapposition is a frequent phenomenon in diabetic patients treated with SES.     

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.     

Incomplete neointimal coverage of sirolimus-eluting stents: angioscopic findings.

OBJECTIVES: The goal of this study was to use angioscopy to investigate the amount of neointimal coverage after sirolimus-eluting stent (SES) implantation. BACKGROUND: Sirolimus-eluting stents reduce intimal hyperplasia. METHODS: We used angioscopy to evaluate 37 consecutive stented coronary artery lesions (15 SES and 22 bare-metal stents [BMS]) in 25 patients (18 men, 7 women) at 3 to 6 months after stent implantation. Angioscopic evaluation focused on: 1) neointimal coverage of stent struts, and 2) the existence of thrombi. The degree of neointimal coverage was classified as grade 0 when there was no neointimal coverage (similar to immediately after the implantation); grade 1 when stent struts bulged into the lumen, but were covered and still translucently visible; grade 2 when stent struts were visible but not clearly seen (not translucent); and grade 3 when stent struts were not visible because they were embedded in the neointima. RESULTS: Thrombi were identified in eight stented segments, tended to be more common with SES (p = 0.14), but were not seen on angiography. Three of the 15 SES (20%) had grade 0 neointimal coverage, and only 2 SES (13.3%) had complete coverage (grades 2/3). In contrast, all 22 BMS showed complete intimal coverage (grades 2/3). Thrombi were more common in stents with incomplete neointimal coverage (p = 0.09). CONCLUSIONS: The SES had incomplete neointimal coverage three to six months after implantation, and this was associated with subclinical thrombus formation.     

Neointimal tissue proliferation after coronary stent implantation without predilatation

INTRODUCTION AND OBJECTIVES: Intravascular ultrasound (IVUS) studies in conventional stent angioplasty with predilatation have demonstrated that late luminal narrowing is caused by neointimal proliferation. In the present study, we analyzed the degree and distribution of in-stent neointimal proliferation after direct stent implantation and aimed to identify variables that predict a proliferative response. MATERIAL AND METHOD: We studied 45 patients who underwent successful stent implantation without predilatation and 23 patients with similar clinical and angiographic characteristics who underwent conventional stent angioplasty with predilatation. IVUS imaging was performed at 7.85+/-2.81 months. The cross-sectional area was measured at five predetermined points in the stented coronary segment. The inflation pressure used in patients who underwent direct stent implantation was higher than that employed in those who underwent conventional angioplasty with predilatation (13+/-3 atm vs 10+/-2 atm; P=.005). RESULTS: Luminal and stent cross-sectional areas were greater in the group that did not undergo predilatation than in the group that did. Neointimal proliferation in the 5 sections analyzed along the axis of the stent was similar in the 2 groups. There was a weak linear relationship between the amount of plaque outside the stent and neointimal proliferation in both the group that underwent predilatation (r=0.37; P=.005) and the group that did not (r=0.33; P=.005). CONCLUSIONS: As with conventional angioplasty, the neointimal proliferation that occurred after direct stent implantation showed a diffuse homogeneous pattern along the length of the stent. There was a weak correlation between this proliferative response and the amount of plaque outside the stent.     

Revisiting late loss and neointimal volumetric measurements in a drug-eluting stent trial: analysis from the SPIRIT FIRST trial.

This study was conducted to reevaluate the significance of angiographic late loss and to assess the agreement between new proposed neointimal volumetric measurements derived from quantitative coronary angiography (QCA) and standard intravascular ultrasound (IVUS)-based parameters. Neointimal volumetric measurements may better estimate the magnitude of neointimal growth after stenting than late loss. In 56 in-stent segments (27, everolimus; 29, bare metal) in the SPIRIT FIRST study, we compared QCA measures with the corresponding IVUS parameters. Two IVUS-late loss models were derived from minimal luminal diameter (MLD) using either a circular model or a so-called projected MLD. QCA-neointimal volume was calculated as follows: stent volume (mean area of the stented segment x stent length) at post procedure - lumen volume (mean area of the stented segment x stent length) at follow-up (the stent length either from nominal stent length or the length measured by QCA). Videodensitometric neointimal volume was also evaluated. Each of the three neointimal volume and percentage volume obstruction by QCA showed significant correlation with the corresponding IVUS parameters (r = 0.557-0.594, P < 0.0001), albeit with a broad range of limits of agreement. Late loss and volumetric measurements by QCA had a broader range of standard deviation than those by IVUS. QCA-volumetric measurements successfully confirmed the efficacy of everolimus-eluting stents over bare metal stents (P < 0.05). Our proposed QCA volumetric measurements may be a practical surrogate for IVUS measurements and a discriminant methodological approach for assessment of treatment effects of drug-eluting stents.     

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.     

Very long sirolimus-eluting stent implantation for de novo coronary lesions

Long-length stenting has a poor outcome when bare metal stents are used. The safety and efficacy of the sirolimus-eluting stent (SES) in long lesions has not been evaluated. Therefore, the aim of the present study was to evaluate the clinical and angiographic outcomes of SES implantation over a very long coronary artery segment. Since April 2002, all patients treated percutaneously at our institution received a SES as the device of choice as part of the Rapamycin Eluting Stent Evaluated At Rotterdam Cardiology Hospital (RESEARCH) registry. During the RESEARCH registry, stents were available in lengths of 8, 18, and 33 mm. The present report includes a predefined study population consisting of patients treated with >36-mm-long stented segments. Patients had a combination of >or=2 overlapping stents at a minimum length of 41 mm (i.e., one 33-mm SES overlapping an 8-mm SES) to treat native de novo coronary lesions. The incidence of major cardiac adverse events (death, nonfatal myocardial infarction, and target lesion revascularization) was evaluated. The study group comprised 96 consecutive patients (102 lesions). Clinical follow-up was available for all patients at a mean of 320 days (range 265 to 442). In all, 20% of long-stented lesions were chronic total occlusions, and mean stented length per lesion was 61.2 +/- 21.4 mm (range 41 to 134). Angiographic follow-up at 6 months was obtained in 67 patients (71%). Binary restenosis rate was 11.9% and in-stent late loss was 0.13 +/- 0.47 mm. At long-term follow-up (mean 320 days), there were 2 deaths (2.1%), and the overall incidence of major cardiac events was 8.3%. Thus, SES implantation appears safe and effective for de novo coronary lesions requiring multiple stent placement over a very long vessel segment.     

Intravascular ultrasound and quantitative coronary angiography assessment of late in-stent restenosis: in vivo human correlation and methodological implications.

Quantitative coronary angiography (QCA) is routinely used for assessment of strategies aimed at reducing in-stent restenosis. Yet QCA enables only the measurement of luminal variation of stented segments and, unlike intravascular ultrasound (IVUS), provides only an indirect estimation of late in-stent neointimal formation, which has a key role in the process of in-stent restenosis. The aims of the present study were to correlate the IVUS measurement of in-stent intimal hyperplasia (IH) with QCA indexes of restenosis, to find out whether QCA is an adequate surrogate of IVUS, and, using either QCA and IVUS data, to define the sample sizes needed to demonstrate the effectiveness of strategies to reduce in-stent restenosis. The database of the European Imaging Laboratory was used to screen 154 stents implanted between 1997 and 2001 and studied by IVUS at 6 +/- 1 months of follow-up. All cases underwent serial QCA assessment (preintervention, postintervention, and follow-up). Only 131 cases with single stent implantation in native coronary arteries were included in the study. Stent restenosis, defined as percent diameter stenosis (DS) > 50%, was present at QCA in 69 out of 131 cases (53%). Linear regression analyses were performed to correlate the amount of IH, calculated by IVUS as the average of all cross-section areas (CSA; mean % IH CSA) and QCA indexes of restenosis (late loss and % DS). A positive significant correlation was found between IVUS mean % IH CSA and QCA % DS (r = 0.74; P < 0.0001) and between IVUS mean % IH CSA and QCA late loss (r = 0.72; P < 0.0001). Based on IVUS measurements of mean % IH CSA, a total sample size of 74 stents would be required in a two-arm comparison to have 0.80 power to detect at 0.05 significant level a 30% difference between two compared groups. Alternatively, adopting the QCA late loss, 230 stents would be required. QCA measurements of late in-stent restenosis are well correlated with IVUS calculation of in-stent neointimal formation. IVUS assessment of IH allows smaller sample sizes than QCA to document significant reductions of in-stent restenosis. Therefore, the use of IVUS should be encouraged in comparison studies aimed at revealing significant neointimal differences in small sample size populations.     

Effect of preintervention plaque burden on subsequent intimal hyperplasia in stented coronary artery lesions

We sought to determine if axial and circumferential distribution of plaque before stenting determines the axial and circumferential distribution of subsequent intimal hyperplasia (IH). We studied 22 patients with a single Palmaz-Schatz stent implanted in a native coronary artery, who underwent intravascular ultrasound (IVUS) imaging before intervention, after stenting, and at 6-month follow-up. For each lesion, 7 locations were analyzed: proximal and distal reference, proximal and distal edge of the stent, proximal and distal location within the body of the stent, and the articulation. Pre- and postintervention and follow-up image slices were precisely aligned and analyzed for pre- and postintervention plaque area and follow-up IH area and thickness. The location of maximal IH area was at or adjacent to the location of maximal preintervention plaque in 17 of 22 of the patients (77%). Similiarly, the circumferential distribution of IH at follow-up paralleled the eccentricity pattern of the native plaque burden in 69% (24 of 35 slices). Using multivariant analysis, the strongest predictor of IH was preintervention plaque area (p = 0.001). IH accumulates axially and circumferentially preferentially at the site of maximal preintervention plaque.     

In-stent pseudo-restenosis due to an organized thrombus six months after implantation of a sirolimus-eluting stent

Restenosis after sirolimuseluting stent (SES) implantation has been reported to be usually focal. We report a case of focal in-stent stenosis discovered angiographically 6 months after SES implantation, despite continuation of dual antiplatelet medication. Continuity and uniform distribution of the struts were confirmed by intravascular ultrasound (IVUS). Material from the lesion was extracted and found to be an organized thrombus on histological inspection. This observation suggests that special attention should be paid to focal stenotic lesions, particularly when IVUS shows proper and circular stent expansion, since it might represent an atypical form of late stent thrombosis.