Does the new generation of drug-eluting stents render bare metal stents obsolete?

Current Status and Outlook of Temporary Implants (Magnesium/Zinc) in Cardiovascular Applications

Medical application materials must meet multiple requirements, and the designed material must mimic the structure, shape. and support the formation of the replacing tissue. Magnesium (Mg) and Zinc alloys (Zn), as a “smart” biodegradable material and as “the green engineering material in the 21st century”, have become an outstanding implant material due to their natural degradability, smart biocompatibility, and desirable mechanical properties. Magnesium and Zinc are recognized as the next generation of cardiovascular stents and bioresorbable scaffolds. At the same time, improving the properties and corrosion resistance of these alloys is an urgent challenge. particularly to promote the application of magnesium alloys. A relatively fast deterioration rate of magnesium-based materials generally results in premature mechanical integrity compromise and local hydrogen build-up, resulting in restricted applicability. This review article aims to give a comprehensive comparison between Zn-based alloys and Mg-based alloys, focusing primarily on degradation and biocompatibility for cardiovascular applications. The recent clinical trials using these biodegradable metals have also been addressed.

Drug-Eluting Stents and Balloons-Materials, Structure Designs, and Coating Techniques: A Review

Controlled drug delivery is a matter of interest to numerous scientists from various domains, as well as an essential issue for society as a whole. In the treatment of many diseases, it is crucial to control the dosing of a drug for a long time and thus maintain its optimal concentration in the tissue. Heart diseases are particularly important in this aspect. One such disease is an obstructive arterial disease affecting millions of people around the world. In recent years, stents and balloon catheters have reached a significant position in the treatment of this condition. Balloon catheters are also successfully used to manage tear ducts, paranasal sinuses, or salivary glands disorders. Modern technology is continually striving to improve the results of previous generations of stents and balloon catheters by refining their design, structure, and constituent materials. These advances result in the development of both successive models of drug-eluting stents (DES) and drug-eluting balloons (DEB). This paper presents milestones in the development of DES and DEB, which are a significant option in the treatment of coronary artery diseases. This report reviews the works related to achievements in construction designs and materials, as well as preparation technologies, of DES and DEB. Special attention was paid to the polymeric biodegradable materials used in the production of the above-mentioned devices. Information was also collected on the various methods of producing drug release coatings and their effectiveness in releasing the active substance.

Ischemic Versus Bleeding Outcomes After Percutaneous Coronary Interventions in Patients With High Bleeding Risk

Patients undergoing percutaneous coronary intervention (PCI) often have high-bleeding-risk (HBR) factors. Dual antiplatelet therapy (DAPT) further increases this risk of bleeding. We sought to compare clinical outcomes according to presence or absence of HBR factors in patients with elevated ischemic risk (DAPT score ≥ 2) undergoing PCI. We evaluated all patients undergoing PCI at MedStar Washington Hospital Center (January 2009 to July 2018) with DAPT score ≥2, which is associated with elevated risk of ischemic events. Patients were categorized as HBR group (HBR score ≥1) or low-bleeding-risk (LBR) group (HBR score = 0). Outcomes included major adverse cardiac events such as target vessel revascularization, stent thrombosis, death, and bleeding events at 30 days, 6 months, 1 year, and 2 years. The final cohort consisted of 7,499 patients: 3,949 patients had LBR features, and 3,550 patients had HBR features. The 2 groups were different at baseline, with HBR patients being older and having a higher prevalence of congestive heart failure and renal dysfunction than the LBR group. The mean DAPT score was 2.96±1.1 for the LBR group and 3.7±1.4 for the HBR group (p <0.001). During follow-up at 30 days, 6 months, and 1 and 2 years, the rates of target vessel revascularization and stent thrombosis were not significantly different between the 2 groups. Bleeding events and all-cause mortality were significantly more frequent in the HBR group than in the LBR group. In conclusion, patients undergoing PCI often have pre-existing risk factors that predispose them to ischemic and bleeding complications. Prolonged duration of DAPT to mitigate ischemic events could lead to a disproportionate increase in bleeding events, especially in HBR patients.

Safety of Endoscopy for Hospitalized Patients With Acute Myocardial Infarction: A National Analysis

INTRODUCTION

Patients hospitalized with myocardial infarction (MI) are at risk of gastrointestinal bleeding because of the need for antiplatelet agents and/or anticoagulation. The data regarding the safety of endoscopy after MI are limited. This study sought to assess mortality rates of patients hospitalized with acute MI who require esophagogastroduodenoscopy or colonoscopy using the National Inpatient Sample (NIS) database.

METHODS

A retrospective cohort analysis of all adult inpatients in the NIS from 2016 admitted for ST-elevation infarction myocardial infarction (STEMI), non-STEMI, or type II non-STEMI was conducted. Data were collected including patient demographics and indication for endoscopy per ICD-10 coding. HCUPnet was used to query NIS to obtain all inpatient mortality. The primary methods included adjusted χ for categorical outcomes, adjusted linear regression for continuous outcomes, and adjusted logistic regression for multivariable analysis.

RESULTS

A total of 1,281,749 patients were admitted for acute coronary syndrome in 2016, and 55,035 of these patients underwent endoscopy In the multivariable regression analysis, those who underwent a GI procedure (odds ratio [OR] 0.80, P value < 0.002) and angiogram (OR 0.48, P value < 0.001) had lower in-hospital mortality, after adjusting for age, Elixhauser index, need for angiogram, sex, race, and hospital type. Endoscopy postcatheterization was not associated with a difference in mortality compared with preangiogram (OR = 0.84, 95% confidence interval 0.60-1.19).

DISCUSSION

Patients who underwent endoscopy are sicker and have higher mortality rates than those who do not undergo endoscopy, but after adjusting for comorbidities, mortality is actually lower. This suggests that endoscopy is safe and should be performed when clinically indicated despite recent cardiac ischemia.

A focused review on optimal coronary revascularisation in patients with chronic kidney disease: Coronary revascularisation in kidney disease

Concomitant chronic kidney disease (CKD) and coronary artery disease (CAD) is known to have poor outcomes. With a thorough literature review, we discuss the pathophysiological basis behind accelerated atherosclerosis in CKD, and the role of percutaneous coronary intervention (PCI) in these patients, focusing on drug-eluting stents, coronary artery bypass grafting, and adverse outcomes. We discuss factors contributing to poor outcomes in these patients, and the need for more work in this subgroup.

Elastic fiber fragmentation increases transmural hydraulic conductance and solute transport in mouse arteries

Transmural advective transport of solute and fluid was investigated in mouse carotid arteries with either a genetic knockout of Fibulin-5 (Fbln5-/-) or treatment with elastase to determine the influence of a disrupted elastic fiber matrix on wall transport properties. Fibulin-5 is an important director of elastic fiber assembly. Arteries from Fbln5-/- mice have a loose, non-continuous elastic fiber network and were hypothesized to have reduced resistance to advective transport. Experiments were carried out ex vivo at physiological pressure and axial stretch. Hydraulic conductance (Lp ) was measured to be 4.99·10-6 ± 8.94·10-7, 3.18·-5 ± 1.13·10-5 (P < 0.01), and 3.57·10-5 ± 1.77·10-5 (P < 0.01) mm·s-1·mmHg-1 for wild-type, Fbln5-/-, and elastase-treated carotids, respectively. Solute fluxes of 4, 70, and 150 kDa FITC-dextran were statistically increased in Fbln5-/- compared to wild-type by a factor of 4, 22, and 3 respectively. 70 kDa FITC-dextran solute flux was similarly increased in elastase-treated carotids by a factor of 27. Solute uptake by Fbln5-/- carotids was decreased compared to wild-type for all investigated dextran sizes after 60 minutes of transmural transport. These changes in transport properties of elastic fiber compromised arteries have important implications for the kinetics of biomolecules and pharmaceuticals in arterial tissue following elastic fiber degradation due to aging or vascular disease.

Clinical Characteristics, Procedural Factors, and Outcomes of Percutaneous Coronary Intervention in Patients With Mechanical and Bioprosthetic Heart Valves

There is scarcity of evidence regarding antiplatelet and anticoagulant therapy in patients with prosthetic valves undergoing percutaneous coronary intervention (PCI). Our goal was to compare clinical outcomes between patients with mechanical or bioprosthetic valves undergoing PCI. The study population comprised patients with either a bioprosthetic or mechanical heart valve in the aortic and/or mitral position undergoing PCI between January 2003 and July 2017. Demographics, admission, and discharge medications as well as procedural details were documented. Outcomes were postprocedural bleeding, length of stay, and in-hospital deaths. Of 211 patients, we identified 119 and 92 patients with a bioprosthetic or mechanical valve, respectively. Mean age was 75 ± 9 years and 66 ± 12 years in bioprosthetic and mechanical valve patients, respectively. Bare-metal stents were used in 18.2% and 30.1% of bioprosthetic and mechanical valve patients, respectively. Major bleeding was documented in 0.8% and 6.5% of bioprosthetic and mechanical valve patients, respectively (p = 0.04). Use of triple therapy (aspirin AND clopidogrel AND oral vitamin K antagonist) was significantly lower in bioprosthetic valve patients compared with mechanical valve patients (12% vs 68%, p <0.001). Our study shows variation in periprocedural anticoagulation and/or antiplatelet choice exists in this population. Patients with mechanical valves experienced higher rates of major bleeding compared with patients with bioprosthetic valves, which could be due to concomitant anticoagulation and dual antiplatelet therapy.

Antiplatelet and anticoagulation regimen in patients with mechanical valve undergoing PCI - State-of-the-art review

A common clinical dilemma regarding treatment of patients with a mechanical valve is the need for concomitant antiplatelet therapy for a variety of reasons, referred to as triple therapy. Triple therapy is when a patient is prescribed aspirin, a P2Y12 antagonist, and an oral anticoagulant. Based on the totality of the available evidence, best practice in 2017 for patients with mechanical valves undergoing percutaneous coronary intervention (PCI) is unclear. Furthermore, the optimal duration of dual antiplatelet therapy after PCI is evolving. With better valve designs that are less thrombogenic, the thromboembolic risks can be reduced at a lower international normalized ratio target, thus decreasing the bleeding risk. This review will offer an in-depth survey of current guidelines, current evidence, suggested approach for PCI in this cohort, and future studies regarding mechanical valve patients undergoing PCI.