Late incomplete stent apposition after sirolimus-eluting stent implantation: a serial intravascular ultrasound analysis.

OBJECTIVES: We sought to identify the frequency of incomplete stent apposition (ISA) in sirolimus-eluting stents (SES) and clarify its findings and clinical sequelae. BACKGROUND: Late-acquired ISA has been reported in bare-metal stents (BMS) and brachytherapy and recently in drug-eluting stents. However, the characteristics of late ISA in SES have not been clarified. METHODS: From the SIRIUS trial, a randomized, multicenter study comparing SES and BMS, serial qualitative intravascular ultrasound (IVUS; at stent implantation and eight-month follow-up) was available in 141 patients (BMS: n = 61; SES: n = 80). The IVUS images were reviewed for the presence of ISA. RESULTS: Incomplete stent apposition at follow-up was observed in 19 patients (BMS: n = 6 [9.8%]; SES: n = 13 [16.3%]; p = NS). Among these, 12 had ISA after intervention and at follow-up (persistent ISA). Late-acquired ISA was seen in the remaining seven cases, all from the SES group (BMS: n = 0; SES: n = 7 [8.7%]; p < 0.05). In late-acquired ISA, there was an increase in external elastic membrane area (after intervention: 16.2 +/- 2.7 m2; follow-up: 18.9 +/- 3.6 mm2; p < 0.05). The location of stent-vessel wall separation was primarily at the stent edges in persistent ISA cases, whereas late-acquired ISA in SES occurred mostly in the mid portion of the stent. There were no negative clinical events reported for any ISA cases at 12-month clinical follow-up. CONCLUSIONS: Late ISA was observed in 8.7% of patients after SES implantation. There were no negative clinical events associated with this IVUS finding at 12-month clinical follow-up; however, careful long-term follow-up will be necessary.     

Late incomplete apposition after drug-eluting stent implantation: incidence and potential for adverse clinical outcomes.

AIM: Late-acquired incomplete stent apposition (ISA) has been documented after drug-eluting stent (DES) implantation; however, its clinical role remains controversial. We sought to investigate the incidence and long-term clinical consequences of late ISA after implantation of sirolimus- (SES) or paclitaxel-eluting stent (PES) in a non-selected population. METHODS AND RESULTS: From our database, we analysed 195 consecutive patients who underwent DES placement (175 with SES and 20 with PES) into native artery lesions and had serial intravascular ultrasound studies (IVUS) performed at index procedure and after 6-8 months. They were clinically followed for 29 +/- 15 months (median of 24.3 months, interquartile range 18.1-31.6 months). Late ISA was defined as separation of at least one stent strut from the vessel wall in a segment without a side-branch and where the immediate post-implantation IVUS revealed complete apposition of stent struts. We identified 10 patients (5.1%) with late ISA, three patients after PES, and seven patients after SES implantation. ISA was localized almost exclusively at body of the stents (nine out of 10 cases). Mean ISA volume and length were 44.5 +/- 41.9 mm(3) and 7.4 +/- 11 mm, respectively. There was a marked increase in vessel volume from 416.0 +/- 163.9 mm(3) at baseline to 514.4 +/- 247.9 mm(3) at follow-up (P = 0.001) with no significant change in plaque volume (232.4 +/- 52.7 at baseline and 226.4 +/- 22.3 mm(3) at follow-up, P = 0.3) in patients who presented with late-acquired ISA. During the follow-up period, one patient with SES and one patient with PES who presented late-acquired ISA had late stent thrombosis and acute myocardial infarction. CONCLUSION: Late-acquired ISA was observed in 5.1% of patients after DES implantation and is related to regional vessel positive remodelling. The relationship between late-acquired ISA and long-term adverse outcomes (e.g. stent thrombosis) requires further analysis.     

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.     

Late-acquired incomplete stent apposition: morphologic characterization

Incomplete stent apposition (ISA) is a lack of contact between stents and the underlying vessel wall, best described by intravascular ultrasound (IVUS). Late acquired incomplete apposition, defined as complete stent apposition at the time of procedure but ISA at follow-up, is an unusual IVUS finding reported in intracoronary brachytherapy, bare-metal stent (BMS), and drug-eluting stent (DES) implantation. Late-acquired ISA is observed relatively more frequently with DES implantation compared with BMS implantation. Possible mechanisms of this phenomenon include focal/extensive vascular remodeling and dissolution of thrombus. While there are conflicting reports regarding the possible impact of this IVUS finding on clinical outcomes, recent reports of DES have suggested its possible association with late adverse cardiac events including late stent thrombosis. In this paper, we review the incidence, location, underlying pathology, and possible clinical sequelae of late-acquired ISA, primarily focusing on that of DES.     

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.     

Effect of the polymer-based, paclitaxel-eluting TAXUS Express stent on vascular tissue responses: a volumetric intravascular ultrasound integrated analysis from the TAXUS IV, V, and VI trials.

AIMS: The TAXUS Express stent has been shown to reduce angiographic restenosis, repeat revascularizations, and neointimal hyperplasia when compared with bare metal stent (BMS) control (TAXUS IV, V, and VI) in individual TAXUS trials. Since intravascular ultrasound (IVUS) methodology and core laboratory were consistent among all three TAXUS trials, an integrated analysis of 956 patients across all IVUS cohorts can be performed providing superior power. METHODS AND RESULTS: In the TAXUS randomized trials, patients received an Express BMS or paclitaxel-eluting TAXUS Express stent. Volumetric analysis was performed on a selected subgroup at implantation and 9 months. Compared with BMS control, TAXUS increased 9-month lumen volumes (144 +/- 79 vs. 179 +/- 95 mm(3); P < 0.0001) due to reduced neointimal volume (66 +/- 49 vs. 27 +/- 30 mm(3); P < 0.0001). This corresponded to a 61% decrease in net lumen volume obstruction (31 +/- 15 vs. 12 +/- 12 mm(3); P < 0.0001). Lumen loss was similar between groups for the proximal 5 mm outside the stent but was reduced in TAXUS at the distal edge (P = 0.0056). Neointimal hyperplasia was significantly reduced in the double-strut region of overlapping TAXUS vs. BMS control and in high-risk patients with diabetes, long lesions, multiple stents, and multiple overlapping stents. Late-acquired incomplete stent apposition (ISA) was more common with moderate-release TAXUS stents. Importantly, there were no major adverse cardiac events or stent thromboses in any late-acquired ISA patient through 2 years. Univariate and multivariable analyses revealed that longer lesion length and previous myocardial infarction are risk factors for late-acquired ISA. CONCLUSION: Integrated analysis of the TAXUS trials shows that the paclitaxel-eluting TAXUS Express stent effectively inhibits in-stent neointimal proliferation, even in high-risk and overlapping stent patients.     

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.     

Randomized comparison of sirolimus and paclitaxel drug-eluting stents for long lesions in the left anterior descending artery: an intravascular ultrasound study.

OBJECTIVES: The goal of this work was to verify whether the superiority of the sirolimus-eluting stent (SES) in inhibiting neointimal hyperplasia could be demonstrated in complex coronary lesions. BACKGROUND: Both the SES (Cypher, Cordis, Miami Lakes, Florida) and the paclitaxel-eluting stent (PES) (Taxus, Boston Scientific, Natick, Massachusetts) have shown a marked reduction in neointimal hyperplasia compared with bare-metal stents. Intravascular ultrasound (IVUS) is the best method to assess arterial response to stent deployment, but few IVUS data are available comparing complex lesions treated with SES or PES. METHODS: We prospectively randomized patients with complex lesions to SES or PES implantation. Intravascular ultrasound and quantitative angiography were performed post-procedure and at 9 months. Mean neointimal hyperplasia area (NIHA), percent of NIHA (NIHA%), mean peristent plaque area (PSPA), and percent of PSPA (PSPA%) were calculated. The primary end point was NIHA% at follow-up. Secondary end points included change in PSPA% and angiographic late luminal loss at follow-up. RESULTS: Of the 100 patients enrolled, 42 receiving the SES and 43 receiving the PES had adequate IVUS assessment. Vessel, plaque, and lumen areas were comparable at follow-up, but NIHA% was significantly lower with SES than PES (7.4 +/- 4.2% vs. 15.4 +/- 8.1%; p < 0.001). A significant reduction in PSPA% was observed with SES (-4 +/- 10% vs. 0 +/- 8%; p = 0.01). Late loss was significantly lower with SES (0.16 +/- 0.19 mm vs. 0.32 +/- 0.33 mm; p = 0.003). CONCLUSIONS: The SES shows a significantly higher inhibition of neointimal hyperplasia compared with PES in complex lesions. However, both stents have excellent IVUS and angiographic results at 9 months. A significant reduction in peri-stent plaque is observed only with SES.     

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.     

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.     

Impact of highly asymmetric stent expansion after sirolimus-eluting stent implantation on twelve-month clinical outcomes

OBJECTIVES: This study investigated the impact of highly asymmetric stent expansion after sirolimus-eluting stent(SES)implantation on clinical outcomes from post procedure to 12 months later. METHODS: Subjects were 118 patients with 171 lesions who underwent SES implantation for angina pectoris and were studied by intravascular ultrasound (IVUS) following the procedure. The stent symmetry index (minimal stent diameter/maximal stent diameter) at the minimal stent area was calculated by IVUS analysis. The patients were divided into two groups for comparative study: those with stent symmetry index > or = 0.7 were classified into the optimal (O) group (93 patients; 145 lesions, mean age 66 +/- 12 years) and those with stent symmetry index < 0.7 were the sub-optimal (S) group (25 patients; 26 lesions, mean age 67 +/- 10 years). RESULTS: Angiographic follow up after 8 months showed no differences in target lesion revascularization (TLR) (O group: 3.1% vs S group: 3.8%, p = 0.833). Multivariate analysis identified the post minimal stent diameter as the independent predictor of TLR (p = 0.038). The stent symmetry index < 0.7 was not a predictor of TLR (p = 0.887). Clinical outcomes after 12 months showed both groups had 0% stent thrombosis and there were no differences in deaths (O group: 2.1% vs S group: 4.0%, p = 0.602). CONCLUSIONS: Highly asymmetric stent expansion after SES implantation may not have a negative impact on clinical outcomes at 12 months.     

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.     

Outcome after acute incomplete sirolimus-eluting stent apposition as assessed by serial intravascular ultrasound

We investigated the fate of postprocedural incomplete stent apposition (ISA) after sirolimus-eluting stent (SES) implantation by evaluating long-term intravascular ultrasound findings in 168 consecutive patients (182 de novo lesions). Postprocedural ISA was defined as > or = 1 stent strut that was clearly separated from the vessel wall with evidence of blood speckle behind the strut without overlapping a side branch. After SES implantation, there were 61 ISA sites in 46 stents in 31 patients (23 at the proximal edge, 7 at the distal edge, and 31 within the stent body). There were no clinical, procedural, or intravascular ultrasound measurement differences between patients and lesions with versus without ISA. At follow-up, 15 acute ISA sites (25%) in 11 patients completely resolved and 40 sites (75%) in 20 patients persisted, although 32 of 46 persisting ISA sites (70%) decreased. There was a greater decrease in effective lumen area and a greater increase in peristent plaque area in the complete-resolution group than in the persistent-ISA group. No lesion developed stent thrombosis or in-stent restenosis (angiographic diameter stenosis > 50%). Six acute ISA sites were also associated with new, late acquired ISA, only 1 of which resulted in aneurysm formation. Although most ISAs after SES implantation do not resolve completely, the incidence of restenosis or thrombosis is not affected.     

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.     

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.     

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.     

Impact of final stent dimensions on long-term results following sirolimus-eluting stent implantation: serial intravascular ultrasound analysis from the sirius trial

OBJECTIVES: We assessed the predictive value of minimum stent area (MSA) for long-term patency of sirolimus-eluting stents (SES) implantation compared to bare metal stents (BMS). BACKGROUND: Although MSA is a consistent predictor of in-stent restenosis, its predictive value in BMS is still limited because of biologic variability in the restenosis process. METHODS: From the SIRolImUS (SIRIUS) trial, 122 cases (SES: 72; BMS: 50) with complete serial intravascular ultrasound (IVUS) (baseline and 8-month follow-up) were analyzed. Postprocedure MSA and follow-up minimum lumen area (MLA) were obtained. Based on previous physiologic studies, adequate stent patency at follow-up was defined as MLA >4 mm(2). RESULTS: In both groups, a significant positive correlation was observed between baseline MSA and follow-up MLA (SES: p < 0.0001, BMS: p < 0.0001). However, SES showed higher correlation than BMS (0.8 vs. 0.65) with a higher regression coefficient (0.92 vs. 0.59). The sensitivity and specificity curves identified different optimal thresholds of MSA to predict adequate follow-up MLA: 5 mm(2) for SES and 6.5 mm(2) for BMS. The positive predictive values with these cutoff points were 90% and 56%, respectively. CONCLUSIONS: In this SIRIUS IVUS substudy, SES reduced both biologic variability and restenosis, resulting in increased predictability of long-term stent patency with postprocedure MSA. In addition, SES had a considerably lower optimal MSA threshold compared to BMS.     

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.     

Stenting after directional coronary atherectomy compared with directional coronary atherectomy alone and stenting alone: a serial intravascular ultrasound study.

BACKGROUND: Directional coronary atherectomy prior to stent implantation (DCA-stent) is expected to be an effective approach to reduce restenosis. The purpose of this study was to determine whether DCA-stent has advantages over DCA alone or stenting alone using serial intravascular ultrasound (IVUS). METHODS AND RESULTS: Serial (pre-, post- and follow-up) IVUS was performed in 187 native coronary lesions treated with each of the 3 strategies. External elastic membrane cross-sectional area (CSA), lumen CSA and plaque CSA were measured. Baseline characteristics were similar. Postprocedural lumen CSA was largest after DCA-stent (11.2+/-2.7 mm2) and DCA (10.8+/-2.5 mm2) than stenting alone (9.0+/-2.9 mm2) (p<0.0005). Follow-up lumen loss was similar. As a result, follow-up lumen CSA was largest after DCA-stent (DCA-stent: 9.1+/-3.4 mm2, DCA: 7.8+/-4.2 mm2, stent: 6.3+/-2.6 mm2, p<0.0005). There was a trend toward a lower rate of restenosis with DCA-stent (DCA-stent, 12.5%; DCA, 18.3%; stent, 18.8%; p=0.57). CONCLUSIONS: DCA-stent is superior to both DCA alone and stent alone in terms of the ability to gain a larger lumen as assessed by IVUS.     

The impact of high pressure vs low pressure stent implantation on intimal hyperplasia and follow-up lumen dimensions; results of a randomized trial.

AIMS: Histology and retrospective clinical studies have indicated that the amount of neointimal hyperplasia is dependent on the arterial injury induced during stent implantation. This study analysed, prospectively, the impact of high vs low pressure stent implantation techniques using a second generation stent on intimal hyperplasia and follow-up lumen dimensions. METHODS AND RESULTS: Post-intervention and follow-up (mean[+/-SD] 5.5+/-1.3 months) angiographic and intravascular ultrasound studies were performed on 120 Multi-Link HP stents randomized to implantation at either low (8-10 atm) or high (16-20 atm) pressure. Intravascular ultrasound measurements of the external elastic membrane, stent, and lumen cross-sectional area were performed at 1 mm axial increments. Peri-stent plaque+media cross-sectional area (external elastic membrane-stent cross-sectional area, intimal hyperplasia cross-sectional area (stent-lumen cross-sectional area at follow-up), intimal hyperplasia thickness and peri-stent tissue growth cross-sectional area (Deltapersistent plaque+media cross-sectional area) were calculated. Intravascular ultrasound demonstrated a larger minimal lumen cross-sectional area post-intervention in the high pressure group (7.3+/-2.0 vs 6.2+/-1.8 mm(2), P<0.001, high vs low pressure group, respectively). At follow-up, the mean intimal hyperplasia cross-sectional area (1.7+/-0.9 vs 1.5+/-0.8 mm(2), P=0.708), the mean intimal hyperplasia thickness (0.16+/-0.12 vs 0.16+/-0.12 mm, P=0.818) and peri-stent tissue proliferation cross-sectional area were not greater in the high pressure group. Thus, the minimal lumen cross-sectional area at follow-up continued to be greater (5.5+/-2.0 vs 4.7+/-1.7 mm(2), P=0.038) in the high pressure group. CONCLUSIONS: High pressure stent implantation results in greater stent expansion even with the less rigid second generation Multi-Link stent. Larger lumen dimensions persist at follow-up, while intimal hyperplasia is not significantly greater after high pressure implantation compared to the low pressure technique.