Overview of the 2007 Food and Drug Administration Circulatory System Devices Panel meeting on the Xience V Everolimus-Eluting Coronary Stent

Impact of total stent length after cobalt chromium everolimus-eluting stent implantation on 3-year clinical outcomes

OBJECTIVES

The objective was to assess whether total stent length (TSL) after cobalt-chromium everolimus-eluting stent (CoCr-EES) implantation was associated with long-term clinical outcomes.

BACKGROUND

The impact of TSL after CoCr-EES implantation on long-term clinical outcomes remained unclear.

METHODS

A total of 1,007 consecutive patients with 1,382 lesions treated only with CoCr-EES were analyzed. Patients and lesions were divided into tertile group: TSL per patient (TSL-P) (PA [8-23 mm], n = 382; PB [23-46 mm], n = 312; and PC [46-204 mm], n = 313), and TSL per lesion (TSL-L) (LA [8-18 mm], n = 486; LB [18-28 mm], n = 475; and LC [28-140 mm], n = 421). The cumulative 3-year incidence of clinically driven target-lesion revascularization (CD-TLR) and definite stent thrombosis (ST) based on TSL-P and TSL-L groupings were accessed.

RESULTS

After inverse probability of weighted adjustment, the cumulative 3-year incidence of CD-TLR for the TSL-P and TSL-L were higher in the PC and LC groups than in the other groups (hazard ratio [HR] 2.92, 95% confidence intervals [CI] 1.66-5.15, P < 0.001 vs. PA; HR 2.49, 95% CI 1.47-4.20, P < 0.001 vs. PB; HR 1.94, 95% CI 1.15-3.28, P = 0.01 vs. LA; HR 2.80, 95% CI 1.73-4.54, P < 0.001 vs. LB, respectively). No significant differences in the cumulative 3-year incidence of definite ST were observed in both TSL-P and TSL-L groups.

CONCLUSIONS

TSL after CoCr-EES implantation has significantly impact on CD-TLR rate through 3 years, but it is not associated with an increased incidence of definite ST. © 2016 Wiley Periodicals, Inc.

Impacts of lesion angle on incidence and distribution of acute vessel wall injuries and strut malapposition after drug-eluting stent implantation assessed by optical coherence tomography

AIMS

To investigate the impact of lesion angle on the incidence and distribution of acute vessel wall injuries and incomplete stent apposition (ISA) following second-generation drug-eluting stent (DES) implantation using optical coherence tomography (OCT). Several ex vivo studies demonstrated that angled arterial walls are exposed to imbalanced mechanical stress from deployed stents.

METHODS AND RESULTS

We included 243 lesions treated with a single DES (148 everolimus-eluting stent and 95 zotarolimus-eluting stent). Angled lesions were defined as lesions with angle ≥45° on an angiogram (n = 58). The vessel wall injuries and ISA were evaluated by OCT. The results were compared with non-angled lesions (<45°, n = 185). The incidence of instent dissection, thrombus, and ISA was significantly higher in the angled group than in the non-angled group (84.5 vs. 63.2%, P < 0.01; 55.2 vs. 35.1%, P < 0.01; 75.9 vs. 44.9%, P < 0.001, respectively). In the angled group, the normalized tissue protrusion volume around the centre of angle (6.59 ± 6.81, mm(3) × 10(2)) was higher than in the distal sub-segment (2.21 ± 2.87, mm3 × 10(2), P < 0.001), in the proximal sub-segment (4.14 ± 5.34, mm3 × 10(2), P = 0.02), and in the non-angled group (3.30 ± 2.81, mm3 × 10(2), P < 0.001). The incidence of major adverse cardiac events within 12 months was similar between the groups.

CONCLUSIONS

Angled coronary lesions had a higher incidence rate of OCT-detected vessel wall injuries and ISA compared with non-angled lesions following second-generation DES implantation. Further studies are needed to understand the long-term clinical significance of these findings.

Incidence and clinical impact of stent fracture after the Nobori biolimus-eluting stent implantation

Background

Stent fracture (SF) after drug‐eluting stent implantation has become an important concern. The aim of this study was to assess the incidence, predictors, and clinical impact of SF after biolimus‐eluting stent.

Methods and Results

A total of 1026 patients with 1407 lesions undergoing the Nobori biolimus‐eluting stent implantation and follow‐up angiography within 9 months after index procedure were analyzed. SF was defined as complete or partial separation of the stent, as assessed by using plain fluoroscopy, intravascular ultrasound, or optical coherence tomography during the follow‐up. We assessed the rate of SF and the cumulative incidence of clinically driven target lesion revascularization and definite stent thrombosis within 9 months. SF was observed in 58 (4.1%) of 1407 lesions and 57 (5.5%) of 1026 patients. Lesions with hinge motion (OR 8.90, 95% CI 3.84 to 20.6, P<0.001), tortuosity (OR 4.16, 95% CI 1.75 to 9.88, P=0.001), and overlapping stents (OR 2.41, 95% CI 0.95 to 6.10, P=0.06) were predictors of SF. Cumulative incidence of clinically driven target lesion revascularization within 9 months was numerically higher in the SF group than that in the non‐SF group (12.0% versus 1.0%). Cumulative incidence of definite stent thrombosis within 9 months tended to be higher in the SF group than that in the non‐SF group (1.7% versus 0.5%).

Conclusions

SF after biolimus‐eluting stent occurs in 4.1% of lesions and appears to be associated with clinically driven target lesion revascularization.

Optical coherence tomography evaluation of late strut coverage patterns between first-generation drug-eluting stents and everolimus-eluting stent

OBJECTIVES

To compare strut coverage patterns between everolimus-eluting stent (EES) and first-generation drug-eluting stents (DES) at more than 12 months after successful implantation, using optical coherence tomography (OCT).

BACKGROUND

No sufficient OCT data has been reported comparing late strut coverage patterns between EES and first-generation DES. The favorable late results after EES implantation could be related to lower rates of uncovered and malapposed struts.

METHODS

A total of 66 DES (21 EES, 23 SES, and 22 PES) that were implanted at least 1 year in advance in 40 patients and met good late angiographic results were evaluated by OCT. The percentage of uncovered and malapposed struts, calculated as the ratio of uncovered or malapposed struts to total struts in all cross-sectional images per stent, was compared among the three groups.

RESULTS

A total of 35,061 struts were analyzed: 11,967 from EES, 11,855 from SES, and 11m239 from PES. The average tissue coverage thickness of the struts per stent was greater in EES than in SES and PES (109 ± 40 µm vs. 72 ± 27 µm and 83 ± 26 µm, respectively; P = 0.001). The percentage of uncovered struts (1.9 ± 4.1% in EES vs. 11.6 ± 12.7% in SES, P = 0.01 and vs. 7.1 ± 5.2% in PES, P < 0.001) and malapposed struts (0.1 ± 0.3% in EES vs. 1.8 ± 3.5% in SES, P = 0.01 and vs. 3.5 ± 5.1% in PES, P = 0.02) was much lower in EES than in first-generation DES, with no significant differences between SES and PES.

CONCLUSIONS

Late strut coverage patterns are not similar between EES and first-generation DES. EES showed a lower percentage of uncovered and malapposed struts.

Crosstalk between apoptosis and autophagy: molecular mechanisms and therapeutic strategies in cancer

Both apoptosis and autophagy are highly conserved processes that besides their role in the maintenance of the organismal and cellular homeostasis serve as a main target of tumor therapeutics. Although their important roles in the modulation of tumor therapeutic strategies have been widely reported, the molecular actions of both apoptosis and autophagy are counteracted by cancer protective mechanisms. While apoptosis is a tightly regulated process that is implicated in the removal of damaged or unwanted cells, autophagy is a cellular catabolic pathway that is involved in lysosomal degradation and recycling of proteins and organelles, and thereby is considered an important survival/protective mechanism for cancer cells in response to metabolic stress or chemotherapy. Although the relationship between autophagy and cell death is very complicated and has not been characterized in detail, the molecular mechanisms that control this relationship are considered to be a relevant target for the development of a therapeutic strategy for tumor treatment. In this review, we focus on the molecular mechanisms of apoptosis, autophagy, and those of the crosstalk between apoptosis and autophagy in order to provide insight into the molecular mechanisms that may be essential for the balance between cell survival and death as well as their role as targets for the development of novel therapeutic approaches.

Modulating autophagy: a strategy for cancer therapy

Autophagy is a process in which long-lived proteins, damaged cell organelles, and other cellular particles are sequestered and degraded. This process is important for maintaining the cellular microenvironment when the cell is under stress. Many studies have shown that autophagy plays a complex role in human diseases, especially in cancer, where it is known to have paradoxical effects. Namely, autophagy provides the energy for metabolism and tumor growth and leads to cell death that promotes tumor suppression. The link between autophagy and cancer is also evident in that some of the genes that regulate Carcinogenesis, oncogenes and tumor suppressor genes, participate in or impact the autophagy process. Therefore, modulating autophagy will be a valuable topic for cancer therapy. Many studies have shown that autophagy can inhibit the tumor growth when autophagy modulators are combined with radiotherapy and/or chemotherapy. These findings suggest that autophagy may be a potent target for cancer therapy.

Comparisons of detailed arterial healing response at seven months following implantation of an everolimus- or sirolimus-eluting stent in patients with ST-segment elevation myocardial infarction

BACKGROUND

The difference of arterial healing response following everolimus-eluting stent (EES) or sirolimus-eluting stent (SES) implantation in patients with ST-segment elevated myocardial infarction (STEMI) has not been compared in detail.

METHODS

Thirty-five patients with STEMI were randomly implanted with an EES or SES (23 EES, 12 SES). At seven months, neointimal thickness (NIT) and strut malapposition were evaluated by optical coherence tomography (OCT) and the grade and heterogeneity of neointimal coverage (NIC) and development of intra-stent thrombi were evaluated by angioscopy.

RESULTS

No significant differences were noted in clinical events experienced by the two groups, although one patient with an EES died following a papillary muscle rupture and one patient with a SES experienced sub-acute stent thrombosis. On OCT, although the EES implants showed a greater NIT than the SES implants (94.8 ± 88.8 μm vs 65.6 ± 63.3 μm, P<0.0001), both the EES and SES showed an excellent suppression of neointimal proliferation in the culprit lesion of STEMI. The frequency of uncovered and malapposed struts of EES was significantly lower than that of SES (2.7% vs. 15.7%, P<0.0001, 0.7% vs. 2.3%, P<0.0001, respectively). The ratio of stents fully covered with neointima of EES group was significantly higher than that of SES group (P=0.04). Angioscopic analysis also showed greater dominant NIC grade with homogenous NIC in EES than in SES (P=0.03, P=0.0002, respectively). The incidence of massive intra-stent thrombus of EES was lower than that of SES (P=0.05).

CONCLUSION

For patients with STEMI, EES may promote better arterial healing response than SES.

Incidence and clinical impact of stent fracture after everolimus-eluting stent implantation

BACKGROUND

Stent fracture (SF) after drug-eluting stent implantation has recently become an important concern because of its potential association with in-stent restenosis and stent thrombosis. However, the incidence and clinical impact of SF after everolimus-eluting stent implantation remain unclear.

METHODS AND RESULTS

A total of 1035 patients with 1339 lesions undergoing everolimus-eluting stent implantation and follow-up angiography 6 to 9 months after index procedure were analyzed. SF was defined as complete or partial separation of the stent, as assessed by plain fluoroscopy or intravascular ultrasound during follow-up. We assessed the rates of SF and major adverse cardiac events, defined as cardiac death, myocardial infarction, stent thrombosis, and clinically driven target lesion revascularization within 9 months. SF was observed in 39 of 1339 lesions (2.9%) and in 39 of 1035 patients (3.8%). Ostial stent location and lesions with hinge motion, tortuosity, or calcification were independent predictors of SF. The rate of myocardial infarction and target lesion revascularization were significantly higher in the SF group than in the non-SF group (5.1% versus 0.4%; P=0.018 and 25.6% versus 2.0%; P<0.001, respectively). Stent thrombosis was more frequently observed in the SF group than in the non-SF group (5.1% versus 0.4%; P=0.018). Major adverse cardiac events within 9 months were significantly higher in the SF group than in the non-SF group (25.6% versus 2.3%; P<0.001).

CONCLUSIONS

SF after everolimus-eluting stent implantation occurs in 2.9% of lesions and is associated with higher rate of major adverse cardiac events, driven by higher target lesion revascularization and stent thrombosis.

Impact of age on clinical outcomes after everolimus-eluting and paclitaxel-eluting stent implantation: pooled analysis from the SPIRIT III and SPIRIT IV clinical trials

AIMS

The impact of age on outcomes following everolimus-eluting stent (EES) or paclitaxel-eluting stent (PES) implantation was evaluated in a patient-level pooled analysis of the SPIRIT III (n=1,002) and SPIRIT IV (n=3,687) trials.

METHODS AND RESULTS

Clinical outcomes with EES compared to PES in elderly (≥ 65 years, n=2,071) and younger (<65 years, n=2,617) patients were evaluated at one year. At one year, elderly patients treated with EES rather than PES showed a significant reduction in target lesion failure (TLF) (3.9% EES vs. 6.8% PES, p=0.006), major adverse cardiac events (MACE) (4.0% EES vs. 7.1% PES, p=0.005), and ischaemia-driven target lesion revascularisation (ID-TLR) (2.0% EES vs. 4.0% PES, p=0.01). Younger patients treated with EES rather than PES also had significantly reduced one-year rates of TLF (4.9% EES vs. 7.9% PES, p=0.003), MACE (5.0% EES vs. 8.0% PES, p=0.004), target vessel myocardial infarction (MI) (2.0% EES vs. 3.4% PES, p=0.04), ID-TLR (3.3% EES vs. 5.5% PES, p=0.01) and stent thrombosis (0.5% EES vs. 1.6% PES, p=0.01).

CONCLUSIONS

In a pooled analysis from the SPIRIT III and IV trials, EES was safer and more effective than PES in both younger and older cohorts as evidenced by lower rates of TLR, TLF and MACE.

Initial clinical experience with an everolimus eluting platinum chromium stent (Promus Element) in unselected patients from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR)

BACKGROUND

The safety and efficacy of the Promus Element stent have been recently demonstrated in a selected population from one randomized trial. The aim of this study was to describe the initial clinical experience with the everolimus eluting platinum chromium stent (Promus Element) in unselected patients from a real life nationwide registry.

METHODS

The Promus Element DES was compared to all other DES implanted in Sweden (with more than 500 implants) from November 2009 to March 2011. The results were assessed using Cox regression.

RESULTS

A total of 13,577 stents (Promus Element, n=2724, Cypher, n=782; Endeavor, n=747; Taxus Liberté, n=1393, Xience V/Promus, n=4832, Resolute, n=1566, Xience Prime, n=4832) were implanted at 8375 procedures. At one year the restenosis rate in the Promus Element was not significantly different from the overall DES group (2.8% vs. 2.7%, adjusted HR:1.17, 95% CI: 0.75-1.75). A significantly lower restenosis rate was observed in the Promus Element when compared with Endeavor (2.8% vs. 5.8%; adjusted HR: 0.44; 95% CI: 0.26-0.74). The stent thrombosis (ST) rate at one year was not significantly different in the Promus Element as compared with the overall DES group (0.2% vs. 0.5% adjusted HR: 0.59; 95% CI: 025-1.40). ST rate was significantly lower as compared with Endeavor stent (0.2% vs. 0.8%; HR: 0.24; 95% CI: 0.08-0.67).

CONCLUSIONS

In a large unselected population the Promus Element stent appears to be safe and effective with a low risk of restenosis and ST.

How safe and how good are drug-eluting stents?

Percutaneous transluminal coronary angioplasty revolutionized therapy for coronary artery disease. This early promise of a viable alternative to surgical treatment of coronary artery disease was thwarted by the high rates of angiographic restenosis. The advent of stenting reduced the rates of restenosis, although it was hindered by the new problem of in-stent restenosis. It was demonstrated that in-stent restenosis was the result of a new pathology in the form of neointimal hyperplasia, which was a maladaptive healing response to bare-metal stent implantation. Recently, the introduction of drug-eluting stents (DES) technology has offered a new solution to the problem of restenosis. Current evidence suggests that although DES have reduced restenosis rates, important concerns have been raised regarding increased stent thrombosis, myocardial infarction and death. The purpose of this article is to examine the efficacy and safety data of DES as highlighted in recent publications and to further discuss the biomolecular mechanisms of accelerated endothelization and stent thrombosis. In addition, we will examine some of the newer stent technologies available.

Sensor to detect endothelialization on an active coronary stent

Background

A serious complication with drug-eluting coronary stents is late thrombosis, caused by exposed stent struts not covered by endothelial cells in the healing process. Real-time detection of this healing process could guide physicians for more individualized anti-platelet therapy. Here we present work towards developing a sensor to detect this healing process. Sensors on several stent struts could give information about the heterogeneity of healing across the stent.

Methods

A piezoelectric microcantilever was insulated with parylene and demonstrated as an endothelialization detector for incorporation within an active coronary stent. After initial characterization, endothelial cells were plated onto the cantilever surface. After they attached to the surface, they caused an increase in mass, and thus a decrease in the resonant frequencies of the cantilever. This shift was then detected electrically with an LCR meter. The self-sensing, self-actuating cantilever does not require an external, optical detection system, thus allowing for implanted applications.

Results

A cell density of 1300 cells/mm² on the cantilever surface is detected.

Conclusions

We have developed a self-actuating, self-sensing device for detecting the presence of endothelial cells on a surface. The device is biocompatible and functions reliably in ionic liquids, making it appropriate for implantable applications. This sensor can be placed along the struts of a coronary stent to detect when the struts have been covered with a layer of endothelial cells and are no longer available surfaces for clot formation. Anti-platelet therapy can be adjusted in real-time with respect to a patient's level of healing and hemorrhaging risks.

Update on the everolimus-eluting coronary stent system: results and implications from the SPIRIT clinical trial program

Drug-eluting stents (DES) have had a major impact in interventional cardiology. Compared to bare metal stents, they significantly reduce restenosis and the need for target vessel revascularization. Four DES are available in the US, the first-generation sirolimus-eluting (Cypher^®) and paclitaxel-eluting (Taxus^®) stents and later approved second-generation everolimus-eluting (Xience V^®) and zotarolimus-eluting (Endeavor^®) stents. The Xience V stent was approved on the basis of clinical efficacy and safety data from 3 studies in the SPIRIT clinical trial program. Within this trial series, the Xience V was superior to its bare metal stent counterpart, the Vision® stent, and noninferior to the paclitaxel-eluting stent for target vessel failure at 9 months. This review provides a comprehensive assessment of the data derived from both the pre- and post-approval randomized controlled trials and registry studies of Xience V that comprise the SPIRIT clinical trial program including recently published mid-term outcomes. The implications of the results in terms of interventional practice will be discussed.

Structural identification and characterization of potential degradants of zotarolimus on zotarolimus-coated drug-eluting stents

Identification and characterization of unknown zotarolimus impurities on zotarolimus-coated drug-eluting stents is an important aspect of product development since the presence of impurities can have a significant impact on quality and safety of the drug product. Four zotarolimus degradation products have been characterized by LC/UV/PDA, LC/MS, LC/MS/MS and NMR techniques in this work. Zotarolimus drug substance and zotarolimus-coated stents were subjected to degradation under heat, humidity, acid or base conditions. The HPLC separation was achieved on a Zorbax Eclipse XDB-C8 column using gradient elution and UV detection at 278 nm. All four impurities generated through the degradation were initially analyzed by LC/MS and/or LC/MS/MS for structural information. Then the isolation of these degradants was carried out by semi-preparative HPLC method followed by freeze-drying of the collected fractions. Finally the degradants were studied by 1H and 13C NMR spectrometry. Based on LC/MS, 1H NMR and 13C NMR data, the structures of these impurities were proposed and characterized as zotarolimus ring-opened isomer (1), zotarolimus hydrolysis product, 16-O-desmethyl ring-opened isomer (2) and zotarolimus lower fragment (3). Degradants 1, 2 and 3 have been observed on degraded zotarolimus-coated stent products.