Clinical safety and efficacy of a novel thin-strut cobalt-chromium coronary stent system: results of the real world Coroflex Blue Registry

Contribution of TRPC Channels in Neuronal Excitotoxicity Associated With Neurodegenerative Disease and Ischemic Stroke

The seven canonical members of transient receptor potential (TRPC) proteins form cation channels that evoke membrane depolarization and intracellular calcium concentration ([Ca²⁺] _i ) rise, which are not only important for regulating cell function but their deregulation can also lead to cell damage. Recent studies have implicated complex roles of TRPC channels in neurodegenerative diseases including ischemic stroke. Brain ischemia reduces oxygen and glucose supply to neurons, i.e., Oxygen and Glucose Deprivation (OGD), resulting in [Ca²⁺] _i elevation, ion dyshomeostasis, and excitotoxicity, which are also common in many forms of neurodegenerative diseases. Although ionotropic glutamate receptors, e.g., N-methyl-D-aspartate receptors, are well established to play roles in excitotoxicity, the contribution of metabotropic glutamate receptors and their downstream effectors, i.e., TRPC channels, should not be neglected. Here, we summarize the current findings about contributions of TRPC channels in neurodegenerative diseases, with a focus on OGD-induced neuronal death and rodent models of cerebral ischemia/reperfusion. TRPC channels play both detrimental and protective roles to neurodegeneration depending on the TRPC subtype and specific pathological conditions involved. When illustrated the mechanisms by which TRPC channels are involved in neuronal survival or death seem differ greatly, implicating diverse and complex regulation. We provide our own data showing that TRPC1/C4/C5, especially TRPC4, may be generally detrimental in OGD and cerebral ischemia/reperfusion. We propose that although TRPC channels significantly contribute to ischemic neuronal death, detailed mechanisms and specific roles of TRPC subtypes in brain injury at different stages of ischemia/reperfusion and in different brain regions need to be carefully and systematically investigated.

Impact of Coronary Stent Architecture on Clinical Outcomes: Do Minor Changes in Stent Architecture Really Matter?

Introduction

The objective of this study was to compare the accumulated clinical outcomes of two Malaysian all-comers populations, each treated with different polymer-free sirolimus-eluting stents (PF-SES) of similar stent design.

Methods

The Malaysian subpopulation of two all-comers observational studies based on the same protocol (ClinicalTrials.gov Identifiers: NCT02629575 and NCT02905214) were combined and compared to a Malaysian-only cohort which was treated with a later-generation PF-SES. The PF-SES’s used differed only in their bare-metal backbone architecture, with otherwise identical sirolimus coating. The primary endpoint was the accumulated target lesion revascularization (TLR) rate at 12 months. The rates of major adverse cardiac events (MACE), stent thrombosis (ST) and myocardial infarction (MI) were part of the secondary endpoints.

Results

A total of 643 patients were treated with either the first-generation PF-SES (413 patients) or second-generation PF-SES (230 patients). Patient demographics were similar in terms of age (p = 0.744), male gender (0.987), diabetes mellitus (p = 0.293), hypertension (p = 0.905) and acute coronary syndrome (ACS, 44.8% vs. 46.1%, p = 0.752) between groups. There were no differences between treatment groups in terms of lesion length (20.8 ± 7.3 mm vs. 22.9 ± 7.9, p = 0.111) or vessel diameter (2.87 ± 0.39 vs. 2.93 ± 0.40, p = 0.052) despite numerically smaller diameters in the first-generation PF-SES group. The second-generation PF-SES tended to have more complex lesions as characterized by calcification (10.3% vs. 16.2%, p = 0.022), severe tortuosity (3.5% vs. 6.9%, p = 0.041) and B2/C lesions (49.2% vs. 62.8%, p < 0.001). The accumulated TLR rates did not differ significantly between the first- and second-generation PF-SES (0.8% vs. 0.9%, p = 0.891). The accumulated MACE rates were not significantly different (p = 0.561), at 1.5% (6/413) and 2.2% (5/230), respectively.

Conclusions

Modifications in coronary stent architecture which enhance the radial strength and radiopacity without gross changes in strut thickness and design do not seem to impact clinical outcomes.

Clinical Trial Registration

ClinicalTrials.gov Identifiers: NCT02629575 and NCT02905214.

Analysis of 12 Months Clinical Outcomes Associated with Implantation of Ultrathin (60 μm) Bare Metal Stent in an Unselected Real-world Population with Coronary Artery Disease

INTRODUCTION

In the era of drug-eluting stents, Bare Metal Stent (BMS) has worked its way up to be recognized in several indications. Moreover, literature suggests that strut thickness has been directly related to the restenosis rate.

AIM

We intended to evaluate the clinical performance of the ultrathin (60 μm) Flexinnium stent (Sahajanand Medical Technologies Pvt. Ltd. Surat, India) for treatment of a wide range of patients with coronary artery disease in routine clinical practice.

MATERIALS AND METHODS

This was an observational, non-randomized, retrospective, single-arm study carried out in real-world patients at three clinical centres of India. A total of 419 consecutive patients' data was collected for the study, who underwent treatment for coronary lesions by implantation of Flexinnium stent, between April 2013 and December 2014. The primary endpoint of the study was Major Adverse Cardiac Events (MACE), a conglomerate of cardiac death, Myocardial Infarction (MI) (Q-wave and non-Q-wave), Target Lesion Revascularization (TLR) and Target Vessel Revascularization (TVR). Any incidence of Stent Thrombosis (ST) was also observed as safety endpoint. These endpoints were observed during in-hospital stay, at 30 days, six months and at 12 months follow up. All data were analysed using the Statistical Package for Social Sciences (SPSS; Chicago, IL, USA) program, version 15.

RESULTS

A total of 491 lesions were treated in 419 patients having mean age of 54.1 years. A total of 525 Flexinnium stents were implanted. There were 243 (58.0%) patients with hypertension. At 12 months the total incidences of MACE were 14 (3.5%). These included 9 (2.3%) cardiac deaths, 1 (0.3%) MI, 3 (0.8%) TLRs and 1 (0.3%) TVR. There was one incidence of definite ST at 12 months follow up.

CONCLUSION

Our results demonstrate that the Flexinnium stent is associated with a low 12 months incidence of MACE in a wide range of real-world population. Long-term follow up would further confirm its clinical performance profile.

The outcomes of patients with very small coronary artery disease treated with thin strut cobalt chromium bare metal stents: an observational study

BACKGROUND

Percutaneous coronary interventions (PCI) in coronary artery disease (CAD) with very small vessel diameters remains controversial and challenging. These lesions are usually more diffuse, calcified and tortuous. The usage of thin strut bare metal stents (BMS) with excellent crossing profiles in a very small caliber coronary lesions has increased the likelihood of procedural success.

OBJECTIVES

This observational study assessed the 9-month clinical outcomes in an 'all-comers' population with very small caliber CAD after implantation of thin strut cobalt chromium BMS.

METHODS

Thin strut cobalt chromium BMS implantation in a priori pre-defined subgroups was investigated in a non-randomized, international, multi-center 'all-comers' observational study. Primary end-point was the 9-month clinically driven target lesion revascularization (TLR) rate. Secondary end-points included the 9-month major adverse cardiac event (MACE) and procedural success rates. Data collection was done using an established electronic data acquisition form with built-in plausibility checks.

RESULTS

A total of 783 patients with a mean age of 70.4 ± 12.8 years were enrolled, 205 (26.2 %) of them had vessel diameters of 2.5 mm and smaller which was defined as CAD with very small reference vessel calibers. Older age and diabetics were associated with higher incidences of very small caliber vessels. The mean reference vessel diameter in the very small vessel group was 2.05 ± 0.27 mm and mean diameter for vessels >2.5 mm was 3.41 ± 0.55 mm. Pre-dilatation was performed more often in the very small vessel patients (52.2 vs. 42.2 %; p value 0.007). There was no difference in the overall technical success rates in very small vessel disease group (97.9 vs. 97.7 %). The 9-month TLR rate was 6.3 % for the very small vessels and 3.7 % for vessels >2.5 mm (p = 0.129). The 9-month and in-hospital MACE rates in the very small vessel group and patient with vessel diameters >2.5 mm were not significantly different (13.1 vs. 9.2 %; p = 0.1265 and 5.2 vs. 3.7 %; p = 0.349) respectively.

CONCLUSION

This study has demonstrated that the use of thin strut cobalt chromium BMS in very small vessel CAD was reasonably safe and efficacious in the context of 'real-world' practice.

Evaluation of safety and efficacy of NexGen - an ultrathin strut and hybrid cell design cobalt-chromium bare metal stent implanted in a real life patient population - the Polish NexGen Registry

INTRODUCTION

Despite the dominance of drug-eluting stents in modern interventional cardiology, there is still a niche for bare metal stents.

AIM

The aim of the Polish NexGen registry was to evaluate the safety and efficacy of a new generation cobalt-chromium NexGen stent in a real life patient population.

MATERIAL AND METHODS

A prospective multi-center registry was conducted in five clinical sites of American Heart of Poland. Three hundred and eighty-three patients who underwent percutaneous coronary intervention (PCI) with NexGen stent implantation were included. Clinical follow-up was performed at 1, 6 and 12 months. Additionally, a group of 42 randomly selected patients underwent control angiography at 6 months (10.96% of study population). The primary endpoint was occurrence of target vessel revascularization (TVR) at 6-month follow-up. Angiographic endpoints included rates of binary restenosis and late lumen loss at 6-month follow-up based on QCA analysis. Multivessel disease was present in more than 70% of patients, and 52.4% of lesions were complex. The main indications for angiography were non-ST elevation acute coronary syndromes (54.8%) and ST elevation myocardial infarction (34.99%).

RESULTS

At 6-month follow-up 47 (12.7%) patients reached the primary endpoint of TVR. The composite of major acute cardiac event rates at 30-day and 6- and 12-month follow-up was 6.01% (n = 23), 18.5% (n = 69) and 25.21% (n = 92) respectively. Control angiography performed after 6 months showed in-stent late loss of 0.66 ±0.71 mm and a binary restenosis rate of 16.7%.

CONCLUSIONS

Our study showed that PCI with the NexGen stent is safe and effective at 6- and 12-month follow-up. Angiographic results showed a satisfactory restenosis rate and low late lumen loss.

Ultra-thin strut cobalt chromium bare metal stent usage in a complex real-world setting. (SOLSTICE registry)

Aim

To report clinical follow-up at 6 months after implantation of the ultra-thin strut cobalt chromium SolarFlex stent in a real-world setting.

Methods and results

Patients (n = 240) with single or multiple vessel coronary artery disease undergoing percutaneous coronary intervention (PCI) at four sites in Europe were enrolled in the SOLSTICE (SolarFlex Stent in Routine Clinical Practice) registry. Follow-up at 6 months was 100 %. Diabetes was present in 29 % of the patients, 30 % presented with acute myocardial infarction and 17 % had unstable angina. Of the patients, 27 % had previously undergone PCI or coronary artery bypass surgery. Lesion complexity was high (50 % B2 + C type lesions). Device success was achieved in 99.7 % of cases and the major adverse cardiac event (MACE) rate was 5.8 % at 6 months of follow-up. Target lesion revascularisation (TLR) was 5.0 % at 6 months.

Conclusions

The SOLSTICE registry showed that in a complex real-world setting the SolarFlex bare metal stent, with ultra-thin struts and customised scaffolding, provided low clinical MACE and TLR rates. These results provide support for the use of the latest generation bare metal stent in contemporary European practice.

Real world experience with an indigenously manufactured stent Cobal C--a retrospective study

BACKGROUND

Second generation bare metal stents made of cobalt chromium alloy are superior to first generation stain less steel stents. The thin struts are shown to reduce clinical and angiographic adverse outcomes.

OBJECTIVE

To study the long term clinical and angiographic outcomes in patients who underwent coronary angioplasty with an indigenously made cobalt chromium bare metal stents with thin strut Cobal+C™ (Relisys).

METHODS

A total of 268 consecutive patients who underwent coronary angioplasty with Cobal+C stents were studied retrospectively. Clinical follow up was done after a minimum period of nine months through telephonic interview and angiographic follow up was done in 80 patients chosen randomly. The end points analyzed included major adverse cardiac events (MACE) at nine months and the rate of binary restenosis at follow up angiogram done between 9 and 15 months post angioplasty.

RESULTS

Thirty four percent were diabetic and 33% had acute myocardial infarction. Females constituted 17%. Mean stent diameter was 2.88 ± 0.28 and mean stent length 18.8 ± 4.2. MACE at nine months was 4.5% with TLR 0.3%. The rate of binary restenosis was 21%. Patients with longer stent lengths and non-compliance with medications had significantly higher rates of binary restenosis.

CONCLUSIONS

The use of Relisys Cobal+C stents was associated with good long term clinical and angiographic outcomes as evidenced by low incidence of MACE and binary restenosis rates for a bare metal stent.

Synergy between direct coronary stenting technique and use of the novel thin strut cobalt chromium Skylor™ stent: the MACE in follow up patients treated with Skylor stent [MILES Study]

BACKGROUND:

Despite significant improvements in stent platform, currently available bare-metal stents (BMS) are still associated with restenosis. Thin-strut design cobalt-chromium alloys hold the promise of improving results of BMS, especially when implanted with direct technique. We performed an observational study to appraise outcomes of the novel Skylor™ stent, stratifying outcomes according to stenting technique.

METHODS and RESULTS:

We included all consecutive patients undergoing coronary stenting with Skylor™ at 2 centers between 2006 and 2009. The primary end-point was the long-term rate of major adverse cardiac events (MACE, i.e. death, myocardial infarction (MI), coronary artery bypass grafting (CABG) or target vessel revascularization (TVR)). As pre-specified analysis, we compared patients undergoing direct stenting versus those stent implantation following pre-dilation. A total of 1020 patients were included (1292 Skylor™ stents), with procedural success obtained in 99%. Comparing patients undergoing direct stenting (66%) versus pre-dilation (34%) at 16±7 months of follow-up, MACE had occurred in, respectively, 8% versus 14% (p=0.001), with death in 1% versus 2% (p=0.380), MI in 1% versus 2% (p=0.032), CABG in 0.2% versus 2% (p=0.012), and TVR in 6% versus 9% [p=0.071]. Even at multivariable analysis with propensity adjustment, direct stenting was associated with significantly fewer MACE [hazard ratio 0.60 [0.38-0.93], p=0.024].

CONCLUSIONS:

This observational study suggests the presence of a beneficial synergy between direct coronary stenting technique and use of the novel thin-strut cobalt-chromium Skylor™ stent in real-world patients undergoing PCI.

Mechanical and Histopathological Comparison between Commercialized and Newly Designed Coronary Bare Metal Stents in a Porcine Coronary Restenosis Model

The aim of this study was to compare the stent designed by Chonnam National University Hospital (designated as CNUH) with commercial cobalt-chromium coronary stent in a porcine coronary overstretch restenosis model. CNUH stent was subjected to mechanical performance tests. Pigs were randomized into two groups in which the coronary arteries (10 pigs, 10 coronaries in each group) had either CNUH stent or control commercial bare metal stent. Histopathologic analysis was assessed at 28 days after stenting. In mechanical performance tests, CNUH stent showed 2.65N, 35.1N, 0.52N, 1.94%, 4.29% in the flat plate radial compression, radial force, 3 point bending, Foreshortening and recoil test, respectively. There was no significant difference in the injury score, internal elastic lamina (IEL), lumen area, neointima area, percent area stenosis, inflammation score and fibrin score between the two groups (1.2±0.35, 4.1±0.41 mm², 2.7±0.56 mm², 1.6±0.47 mm², 36.7±11.2%, 1.2±0.62, 0.2±0.34 in CNUH stent group vs. 1.2±0.38, 3.7±0.64 mm², 2.5±0.49 mm², 1.5±0.61 mm², 36.3±12.17%, 1.1±0.12, 0.4±0.46 in commercial stent group, respectively). In the mechanical performance test, CNUH stent showed the moderated performance under the guideline of FDA. CNUH stent demonstrated similar histological reactions compared with commercial cobalt-chromium stent in a porcine coronary overstretch restenosis model.

[Imaging of coronary stents using multislice computed tomography]

Coronary artery stenting has become the most important form of coronary revascularization. With the introduction of drug-eluting stents (DES) the rate of restenosis has declined but due to the delayed formation of intimal tissue the incidence of late (>30 days after stent placement) and very late thrombosis of the stents is higher for DES. Visualization of the stent lumen is possible with multislice computed tomography (MSCT) but blooming artifacts hamper the delineation of the stent lumen. The severity of these artifacts and thus the width of the visible stent lumen depends on several factors, such as the thickness of the stent struts, the design of the stent and the underlying material itself. The most important factor influencing the extent of blooming artifacts is the convolution kernel selected for image reconstruction. Dedicated, edge-enhancing kernels offer superior lumen visualization compared to the soft or medium kernels used for coronary artery imaging. The trade-off using edge-enhancing kernels is an increase in image noise.Despite all efforts undertaken to enhance stent lumen visualization, stent imaging is still a challenge in MSCT. In the majority of stents currently used, sufficient lumen visualization is only possible in stents with a diameter larger than 3 mm. A position of the stent in the proximal segments of the coronary artery tree facilitates delineation of the stent lumen not only because of the relatively little motion but also because of the lesser extent of blooming artifacts obscuring the stent lumen if the stent is oriented perpendicular to the z-axis of the scanner.