Intravascular ultrasound analysis of small vessel lesions treated with the Sparrow coronary stent system: results of the CARE II trial.

OBJECTIVES: The aim of this study was to evaluate the Sparrow sirolimus-eluting stent (Sparrow-SES) against the Sparrow bare-metal stent (Sparrow-BMS) and conventional balloon-expandable bare-metal stent (BMS: Driver/Micro-Driver stent, Medtronic Vascular, Santa Rosa, CA). BACKGROUND: The Sparrow stent (Biosensors International, Singapore) consists of a guide wire-based, self-expandable, ultra-thin nitinol stent. The performance of this device with sirolimus in a fully biodegradable polymer has not been determined. METHODS: A total of 74 patients were included in this intravascular ultrasound (IVUS) sub-study of the CARE II trial, which was a prospective, randomized, multicenter trial in the treatment of single de novo native coronary artery lesions in vessels ranging from 2.0 mm to 2.75 mm in diameter (Sparrow-SES: n = 31, Sparrow-BMS: n = 22, BMS: n = 21). RESULTS: Stent volume index (VI) was significantly increased 8-month later in Sparrow-SES and Sparrow-BMS, but not in BMS (4.0 ± 1.0 to 4.6 ± 1.0 mm(3) /mm, p<0.0001, 4.0 ± 0.6 to 4.4 ± 0.8 mm(3) /mm, p<0.05, and 5.2 ± 1.0 to 5.1 ± 0.9 mm(3) /mm, p=0.421, respectively). % neointimal obstruction in Sparrow-SES was significantly smaller than those in Sparrow-BMS and BMS at follow-up (17.6 ± 9.4 vs. 36.2 ± 13.8 and 39.9 ± 11.1%, p<0.001). Sparrow-SES showed a mean 15% stent expansion and good suppression of neointimal proliferation, resulting in a significantly lower percentage of change in lumen VI during follow-up period (Sparrow-SES: -6.2 ± 16.2%, Sparrow-BMS: -30.4 ± 11.6%, BMS: -40.4 ± 10.0%, p<0.001). CONCLUSIONS: The self-expanding Sparrow-SES demonstrated chronic stent expansion, good suppression of neointimal proliferation and resulted in a more preserved lumen in stented small vessels compared with the Sparrow-BMS and conventional balloon expandable BMS.

Short- and mid-term intravascular ultrasound analysis of the new zotarolimus-eluting stent with durable polymer ­ results from the RESOLUTE trial ­.

BACKGROUND: The Resolute stent is a newly developed system with a bio-histocompatible polymer that allows programmed drug delivery up to 180 days. The aim of this intravascular ultrasound (IVUS) analysis was to evaluate the short- (4 months) and mid-term (9 months) efficacy using the Resolute stent. METHODS AND RESULTS: Data were derived from the RESOLUTE trial, a prospective, multicenter, non-randomized, single-arm study to treat de novo native coronary artery lesions. This trial included 2 cohorts with different follow-up periods, and all enrollment patients in this trial received IVUS study. Follow-up IVUS was available in 24 patients (4-month group) and 88 patients (9-month group). Neointimal obstruction (%) was defined as neointimal volume divided by stent volume. Cross-sectional narrowing (CSN, %) was defined as neointimal area divided by stent area. No significant differences in vessel, lumen and stent volume at post-procedure were observed within stented segments between the 4- and 9-month follow-up groups. Although neointimal volume and % neointimal obstruction showed no significant difference between the 2 groups (% neointimal obstruction: 2.2 ± 2.5 vs 3.7 ± 4.0%, P=0.09), maximum CSN was significantly larger in the 9-month group. There were 7 cases of late incomplete stent apposition. CONCLUSIONS: These IVUS results showed minimum growth of neointimal proliferation by the Resolute stent throughout the stented segment up to 9 months follow up.

Safety and efficacy of low-dose paclitaxel utilizing the cobra-P drug-eluting stent system with a novel biodegradable coating in de novo coronary lesions: the PLUS-ONE first-in-man study.

BACKGROUND: The Cobra-P drug-eluting stent (DES) system consists of cobalt chromium alloy with bio-absorbable siloxane sol-gel matrix coating that elutes low dose paclitaxel within 6 months. The aim of this first-in-man trial was to evaluate the safety and performance of 2 doses of the Cobra-P DES. METHODS: A total of 60 lesions (54 patients) were sequentially assigned to 2 different paclitaxel doses: group A (3.7 µg/18mm, n=30) or group B (8 µg/18mm, n=30). The primary endpoint was MACE at 4 months defined as cardiac death, myocardial infarction, and target lesion revascularization. RESULTS: Patient and lesion characteristics were matched between the 2 groups except for male sex. MACE at 4 months was 3.3% and 0% respectively (P=1.000) and at 1-year follow-up remained unchanged. In-stent late loss at 4 months was similar in both groups (0.36 ± 0.30mm and 0.34 ± 0.20mm P=.773). CONCLUSIONS: In this FIM study, implantation of the Cobra-P low dose paclitaxel-eluting stent with a bioabsorbable sol-gel coating was proven to be feasible and safe. Moderate neointimal proliferation was observed as well as an acceptable MACE rate up to 1 year.

Intravascular ultrasound insights from the Cobalt Chromium Stent With Antiproliferative for Restenosis II (COSTAR II) trial comparing CoStar and Taxus paclitaxel-eluting stents.

BACKGROUND: Dedicated IVUS analyses of the second CObalt chromium STent with Antiproliferative for Restenosis (COSTAR II) trial have not been documented. We aim to compare IVUS findings between CoStar paclitaxel-eluting stent (PES) and Taxus PES in patients enrolled in the COSTAR II trial. We also attempted to examine the possible regional impact of multiple stenting. METHODS AND MATERIALS: Among the 1700 patients enrolled, 238 were assigned to an IVUS cohort including 168 patients treated by provisional multiple stenting. At 9 months, qualitative and quantitative IVUS observations including incomplete stent apposition (ISA) and neointimal proliferation (neointimal obstruction: neointimal volume/stent volume ×100) were compared between CoStar and Taxus PESs. RESULTS: In qualitative analysis, late-acquired ISA was observed in 1 patient treated by Taxus PES. Impaired strut continuity suggestive of stent fracture was observed in 2 out of 33 patients treated by multiple CoStar, and 4 out of 21 patients treated by multiple Taxus (P=.14). No such findings were found in single-stented patients in either stent subset. Quantitative analysis showed greater neointimal obstruction in CoStar (19.7%±13.4%, n=52) than in Taxus (10.7%±9.9%, n=38), whereas no significant difference in neointimal obstruction was found between single and multiple stenting in either CoStar or Taxus PES. CONCLUSIONS: The CoStar PES exhibits greater neointimal proliferation compared with Taxus PES at 9 months but with similar qualitative outcomes including late-acquired ISA. IVUS findings suggestive of stent fracture were found only in multiple-stenting cases irrespective of the stent used.

Impact of polymer formulations on neointimal proliferation after zotarolimus-eluting stent with different polymers: insights from the RESOLUTE trial.

BACKGROUND: Polymer formulation may affect the efficacy of drug-eluting stents. Resolute, Endeavor, and ZoMaxx are zotarolimus-eluting stents with different stent platforms and different polymer coatings and have been tested in clinical trials. The aim of this analysis was to compare the efficacy of zotarolimus-eluting stents with different polymers. METHODS AND RESULTS: Data were obtained from the first-in man trial or first randomized trials of each stent, The Clinical RESpOnse EvaLUation of the MedTronic Endeavor CR ABT-578 Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions (RESOLUTE), Randomized Controlled Trial to Evaluate the Safety and Efficacy of the Medtronic AVE ABT-578 Eluting Driver Coronary Stent in De Novo Native Coronary Artery Lesions (ENDEAVOR II), and ZoMaxx I trials. Follow-up intravascular ultrasound analyses (8 to 9 months of follow-up) were possible in 353 patients (Resolute: 88, Endeavor: 98, ZoMaxx: 82, Driver: 85). Volume index (volume/stent length) was obtained for vessel, stent, lumen, peristent plaque, and neointima. Cross-sectional narrowing was defined as neointimal area divided by stent area (%). Neointima-free frame ratio was calculated as the number of frames without intravascular ultrasound-detectable neointima divided by the total number of frames within the stent. At baseline, vessel, lumen, and peristent plaque volume index were not significantly different among the 4 stent groups. At follow-up, percent neointimal obstruction was significantly lower in Resolute compared with Endeavor, ZoMaxx, and Driver (Resolute: 3.7±4.0, Endeavor: 17.5±10.1, ZoMaxx: 14.6±8.1, Driver: 29.4±17.2%; P<0.001). Greater maximum cross-sectional narrowing and higher neointima-free frame ratio, suggesting less neointimal coverage, were observed in Resolute compared with other stent groups. Multiple regression analysis confirmed that the biodurable polymer used in Resolute independently correlated with neointimal suppression among 3 zotarolimus-eluting stents. CONCLUSIONS: The different polymer formulations significantly affect the relative amount of neointima for zotarolimus-eluting stents. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00248079.

Intravascular ultrasound results from the ENDEAVOR IV trial: randomized comparison between zotarolimus- and paclitaxel-eluting stents in patients with coronary artery disease.

OBJECTIVES: The aim of this study was to compare the vessel response between zotarolimus-eluting stents (ZES) and paclitaxel-eluting stents (PES) using intravascular ultrasound. BACKGROUND: The ENDEAVOR IV (Randomized Comparison of Zotarolimus- and Paclitaxel-Eluting Stents in Patients With Coronary Artery Disease) trial was a randomized controlled study of zotarolimus-eluting, phosphorylcholine-coated, cobalt-alloy stents for the treatment of de novo coronary lesions compared with using PES for the same treatment. METHODS: Data were obtained from patients with serial (baseline and 8-months follow-up) intravascular ultrasound analysis available (n = 198). Volumetric analysis was performed for vessel, lumen, plaque, stent, and neointima. Cross-sectional narrowing (given as percentage) was defined as neointimal area divided by stent area. Neointima-free frame ratio was calculated as the number of frames without intravascular ultrasound-detectable neointima divided by the total number of frames within the stent. Subsegment analysis was performed at every matched 1-mm subsegment throughout the stent. RESULTS: At follow-up, the ZES group showed significantly greater percentage of neointimal obstruction (16.6 +/- 12.0% vs. 9.9 +/- 8.9%, p < 0.01) and maximum cross-sectional narrowing (31.8 +/- 16.1% vs. 25.2 +/- 14.9%, p < 0.01) with smaller minimum lumen area than the PES group did. However, the incidence of maximum cross-sectional narrowing >50% was similar in the 2 groups. Neointima-free frame ratio was significantly lower in the ZES group. In overall analysis, whereas the PES group showed positive remodeling during follow-up (13.7 +/- 4.2 mm(3)/mm to 14.3 +/- 4.3 mm(3)/mm), the ZES group showed no significant difference (12.7 +/- 3.6 mm(3)/mm to 12.9 +/- 3.5 mm(3)/mm). In subsegment analysis, significant focal positive vessel remodeling was observed in 5% of ZES and 25% of PES cases (p < 0.05). CONCLUSIONS: There were different global and focal vessel responses for ZES and PES. Both drug-eluting stents showed a similar incidence of lesions with severe narrowing despite ZES having a moderate increase in neointimal hyperplasia compared with neointimal hyperplasia in PES. There was a relatively lower neointima-free frame ratio in ZES, suggesting a greater extent of neointimal coverage. (The ENDEAVOR IV Clinical Trial: A Trial of a Coronary Stent System in Coronary Artery Lesions; NCT00217269).

Characterization of late incomplete stent apposition: a comparison among bare-metal stents, intracoronary radiation and sirolimus-eluting stents.

BACKGROUND: Late incomplete stent apposition (LISA) develops following implantation of conventional bare-metal stents (BMS) or drug-eluting stents, or after adjunctive intracoronary radiation (IR). However, no study has systematically compared the morphology of LISA seen with various treatment modalities. PURPOSE: To compare the morphometric features of LISA accompanying BMS, IR or sirolimus-eluting stents (SES) using serial intravascular ultrasound (IVUS). METHODS: A query of Stanford University's IVUS database of the Cardiovascular Core Analysis Laboratory was performed to identify LISA cases. Dedicated software programs were used for volumetric IVUS analyses. RESULTS: In 30 LISA cases (12 BMS, 6 IR and 12 SES), there was no intertreatment difference in the degree of LISA (lumen area minus stent area at follow up). Serial analyses of LISA segments showed that vessel area of SES and IR showed significant increase at follow up as compared with post procedure, while there was no significant change in plaque area. In contrast, the BMS group showed no increase in vessel area, whereas plaque area revealed significant reduction. Eight of 12 BMS cases were treated by directional atherectomy before stenting; however, there was no difference in the area change between patients with or without pre-stent atherectomy. Post-procedure plaque thickness beneath the stent struts of LISA was thinner for SES as compared with BMS. CONCLUSIONS: Plaque reduction primarily contributes to LISA after BMS, whereas vessel expansion is the predominant factor in LISA development for IR and SES. Thus, the mechanism of LISA may vary among different interventional treatments.

[Intravascular ultrasound guided polytetrafluoroethylene coronary stent graft implantation in a patient with a large coronary pseudoaneurysm at eight months after coronary intervention: a case report].

A 67-year-old man with exertional angina presented with a large pseudoaneurysm of the right coronary artery at eight months after balloon angioplasty. Intravascular ultrasound revealed a large saccular pseudoaneurysm of 10.9 x 5.7 mm diameter at the proximal segment of the right coronary artery. Complete closure of the coronary pseudoaneurysm was successfully obtained using a coronary stent graft consisting of a thin flexible polytetrafluoroethylene (PTFE) membrane placed between two stents using a unique sandwich technique. Follow-up angiography and intravascular ultrasound revealed no significant restenosis in the PTFE stent graft segment. PTFE coronary stent graft implantation is a feasible, safe and useful method to treat a large coronary pseudoaneurysm after coronary intervention.