Rapid adoption of drug-eluting stents: clinical practices and outcomes from the early drug-eluting stent era

Nanomaterial coatings applied on stent surfaces

The advent of percutaneous coronary intervention and intravascular stents has revolutionized the field of interventional cardiology. Nonetheless, in-stent restenosis, inflammation and late-stent thrombosis are the major obstacles with currently available stents. In order to enhance the hemocompatibility of stents, advances in the field of nanotechnology allow novel designs of nanoparticles and biomaterials toward localized drug/gene carriers or stent scaffolds. The current review focuses on promising polymers used in the fabrication of newer generations of stents with a short synopsis on atherosclerosis and current commercialized stents, nanotechnology's impact on stent development and recent advancements in stent biomaterials is discussed in context.

Cobalt-chromium KAname™ coRonary stEnt system in the treatment of patients with coronary artery disease (KARE study)

OBJECTIVES

To evaluate the safety and effectiveness of the Kaname™ cobalt-chromium (Co-Cr), thin strut, bare metal stent (BMS) system for the treatment of coronary artery lesions.

BACKGROUND

Despite widespread use of drug-eluting stents, a certain percentage of patients with coronary artery disease are still treated with BMS. Therefore, it is essential to evaluate their clinical performance.

METHODS

Two hundred eighty-two patients were enrolled in this prospective, single-arm study including a predefined subset of 79 patients with small vessels. The primary end-point was freedom from target vessel failure (TVF) at 6 months. Key angiographic and intravascular ultrasound (IVUS) end-points were late loss, diameter stenosis, binary restenosis, and neointimal hyperplasia volume.

RESULTS

Freedom from TVF at 6 months was 93.3% and at 1 year 90.8% in total population, and 92.4% and 87.3% in small vessels, respectively. Clinically driven target lesion revascularization (TLR) rates at 6 and 12 months were 4.3% and 6.4% in total population, and 3.8% and 7.6% in small vessels, respectively. At 6 months in-stent late loss was 0.75 ± 0.43 mm and binary restenosis rate was 16.9% in total population, and 0.64 ± 0.40 mm and 26.1% in small vessels, while IVUS assessed neointimal hyperplasia volume at 6 months was 128.9 ± 42.6 mm(3) for total population. There were no definite and probable stent thromboses up to 12 months.

CONCLUSIONS

Results indicate good safety and effectiveness of the Kaname™ stent with clinically equivalent results in small and larger vessels, as such providing useful treatment option for patients with ischemic heart disease considered for BMS implantation.

Overview of Technical and Cost Considerations in Complex Percutaneous Coronary Intervention

Complex percutaneous coronary intervention (PCI), encompassing an ever-expanding range of challenging lesion sets and patient populations, accounts for a significant proportion of PCI procedures being performed currently. Specific lesion types associated with lower rates of procedural success and higher rates of recurrence or major adverse cardiac events (MACE) include multivessel disease, unprotected left main coronary artery disease, fibrocalcific or undilatable lesions, chronic total occlusions, degenerated saphenous vein graft lesions, thrombotic lesions, and bifurcation disease. Validated tools and technical strategies currently exist to address most procedural scenarios encountered and should be familiar to the complex PCI operator. Anticipated clinical outcomes, projected resource utilization, and cost considerations should all factor into the decisions of when, how, and in whom to intervene.

Implementing tissue engineering and regenerative medicine solutions in medical implants

BACKGROUND

Surgical implants are widely used in the medical field but their long-term performance is limited due to failure of integration with tissues. This manuscript describes very well-known problems associated with implants and discusses novel solutions used in tissue engineering and regenerative medicine that can be implemented in this uncommonly discussed medical area.

SOURCES OF DATA

General and medical literature describing modifications of medical and surgical implants, biofunctionalization, tissue engineering and regenerative medicine.

AREAS OF AGREEMENT

Procedures for surgical implantation have grown substantially in the last few decades and provided improved quality of life for patients, regardless of area of implantation and device type and purpose.

AREAS OF CONTROVERSY

In general, implants fail because of lack of long-term integration with the surrounding tissues. Implant manufacturers have not addressed implant failure from the point of view of biointegration. In addition, some medical practitioners are inclined to treat implant failure by using anti-infection methods to prevent bacterial adhesion. However, both approaches are conceptually limited, as discussed in this manuscript.

GROWING POINTS

Implantation in the future will not be limited to medically needed procedures but also to a growing number of cosmetic body transformation procedures, which may include perceived 'improved implant functions' over natural tissues or organs. An additional trend is that implant procedures are being progressively performed in younger individuals.

AREAS TIMELY FOR DEVELOPING RESEARCH

Current implants generally do not allow the physician to have controlled long-term access to internal tissues in contact with the implants, for example to release specific compounds when medically needed to the problem area.

Clinical outcomes after zotarolimus and everolimus drug eluting stent implantation in coronary artery bifurcation lesions: insights from the RESOLUTE All Comers Trial

OBJECTIVE

We investigated clinical outcomes after treatment of coronary bifurcation lesions with second generation drug eluting stents (DES).

DESIGN

Post hoc analysis of a randomised, multicentre, non-inferiority trial.

SETTING

Multicentre study.

PATIENTS

All comers study with minimal exclusion criteria.

INTERVENTIONS

Patients were treated with either zotarolimus or everolimus eluting stents. The patient population was divided according to treatment of bifurcation or non-bifurcation lesions and clinical outcomes were compared between groups.

MAIN OUTCOMES MEASURES

Clinical outcomes within 2-year follow-up.

RESULTS

A total of 2265 patients were included in the present analysis. Two-year follow-up data were available in 2223 patients: 1838 patients in the non-bifurcation group and 385 patients in the bifurcation group. At 2-year follow-up the bifurcation and the non-bifurcation lesion groups showed no significant differences in terms of cardiac death (2.3 vs 2.1, p=0.273), target lesion failure (9.7% vs 13.8%, p=0.255), major adverse cardiac events (11.5% vs 15.1%, p=0.305), target lesion revascularisation (4.7% vs 6.0%, p=0.569), and definite or probable stent thrombosis (1.6% vs 1.8%, p=0.419).

CONCLUSIONS

The use of second generation DES for the treatment of coronary bifurcation lesions was associated with similar long term mortality and clinical outcomes compared with non-bifurcation lesions.

Response gene to complement 32 promotes vascular lesion formation through stimulation of smooth muscle cell proliferation and migration

OBJECTIVE

The objectives of this study were to determine the role of response gene to complement 32 (RGC-32) in vascular lesion formation after experimental angioplasty and to explore the underlying mechanisms.

METHODS AND RESULTS

Using a rat carotid artery balloon-injury model, we documented for the first time that neointima formation was closely associated with a significantly increased expression of RGC-32 protein. Short hairpin RNA knockdown of RGC-32 via adenovirus-mediated gene delivery dramatically inhibited the lesion formation by 62% as compared with control groups 14 days after injury. Conversely, RGC-32 overexpression significantly promoted the neointima formation by 33%. Gain- and loss-of-function studies in primary culture of rat aortic smooth muscle cells (RASMCs) indicated that RGC-32 is essential for both the proliferation and migration of RASMCs. RGC-32 induced RASMC proliferation by enhancing p34(CDC2) activity. RGC-32 stimulated the migration of RASMC by inducing focal adhesion contact and stress fiber formation. These effects were caused by the enhanced rho kinase II-α activity due to RGC-32-induced downregulation of Rad GTPase.

CONCLUSIONS

RGC-32 plays an important role in vascular lesion formation following vascular injury. Increased RGC-32 expression in vascular injury appears to be a novel mechanism underlying the migration and proliferation of vascular smooth muscle cells. Therefore, targeting RGC-32 is a potential therapeutic strategy for the prevention of vascular remodeling in proliferative vascular diseases.