Publications

This paper presents the study carried out using the extended Equivalent Mortar Volume (EMV) mix design technique, for concrete made of recycled aggregates (RA) and steel fibre (SF).The expansion of the EMV approach is necessary to encourage the use of fine recycled aggregates (FRA) in concrete manufacture.To this end, the same replacement ratio obtained for coarse recycled aggregates (CRA) using the EMV principles, was applied to the FRA for concrete production.Furthermore, SF was added to improve the mechanical behaviour of RA-concrete developed with this method.Altogether, four mixes were developed using a constant waterto-cement ratio of 0.42 thus: reference mix labelled conventional concrete (CC) prepared with natural aggregates (NA); crushed aggregate concrete (CAC) mix designed with the conventional method and made of 100% RA; blended aggregate concrete (BAC) mix prepared with the EMV guide and composed of both NA and RA; and steel fibre-reinforced blended aggregate concrete (SFRBAC) mix prepared by adding optimum SF to the BAC mix.Then, cubical, cylindrical and prismatic specimens were produced from the mixes to investigate different properties of concrete.The experimental results show that the mechanical properties of concrete are not adversely affected by the presence of FRA.Also, the EMV mix design provision offers a better result than its companion conventional approach, even with about 30% reduction in cement content.The addition of SF mainly controlled crack development and induced a ductile failure mode.

No abstract is provided for this article.

Introduction and objectives At present, the effect of paclitaxel on tissue structure at the edges of Taxus® stents is unknown. The objective of this study was to investigate in vivo the temporal changes occurring at the edges of paclitaxel-eluting stents using intravascular ultrasound radiofrequency (IVUS-RF) data analysis. Methods The study included 24 patients who had a total of 26 paclitaxel-eluting stented segments. In all patients, IVUS-RF imaging was performed 5 mm proximally and 5 mm distally to the stent edges 6 months after stent implantation. For subsequent analysis, proximal and distal segments were divided into five 1-mm subsegments. Results In the first 2 subsegments adjacent to the proximal edge of the stent, the vessel wall had grown to compensate for plaque growth without affecting the vessel lumen, while in the remaining three subsegments there was overcompensation (ie, the vessel wall increased to greater than the plaque size). Consequently, the lumen had increased in size. At the distal edge of the stent, overcompensation was observed in all five subsegments and the lumen had increased in size. In general, proximal and distal growth was due to an increase in fibrolipid plaque (P <.001 and P <.001, respectively) along with a decrease in the necrotic core (P =.014 and P <.001, respectively) and the presence of dense calcium (P <.001 and P <.001, respectively). Conclusions Serial expansive vascular remodeling was observed at proximal and distal stent edges. Remodeling occurred in response to tissue growth, which was mainly due to increased fibrofatty tissue. Introducción y objetivos En la actualidad se desconoce el efecto de paclitaxel en la composición tisular en los segmentos adyacentes (bordes) del stent Taxus®. El objetivo de este estudio fue investigar in vivo los cambios temporales que se producen en los bordes del stent liberador de paclitaxel según un análisis de los datos de radiofrecuencia procedentes de ecografía intravascular (EIV). Métodos En total participaron 24 pacientes (26 segmentos con stents liberadores de paclitaxel). Se obtuvieron imágenes con EIV de los 5 mm proximales y los 5 mm distales de los bordes del stent transcurridos 6 meses del implante. Para realizar un análisis posterior, los segmentos proximales y distales se fraccionaron en cinco subsegmentos de 1 mm cada uno. Resultados En los primeros dos subsegmentos adyacentes al stent del borde proximal, la pared del vaso crece para compensar el crecimiento de la placa sin que ello afecte a la luz, mientras en los siguientes 3 subsegmentos se observó una sobrecompensación (la pared del vaso aumentó más que el tamaño de la placa). Por lo tanto, aumentó el tamaño luminal. En el borde distal, se observó sobrecompensación en todos los subsegmentos, seguida de un aumento del tamaño luminal. En general, el crecimiento proximal y distal se basó en un aumento de la placa fibrolipídica (p < 0,001 y p < 0,001 respectivamente), con una disminución del núcleo necrótico (p = 0,014 y p < 0,001 respectivamente) y un contenido denso de calcio (p < 0,001 y p < 0,001 respectivamente). Conclusiones Se observó un remodelado vascular expansivo y seriado en los bordes proximal y distal del stent, para acomodar un crecimiento tisular principalmen te debido al aumento del tejido fibrolipídico.

Bioresorbable scaffolds (BRS) represent a novel approach in coronary stent technology. In contrast to the metallic stents, they provide transient scaffolding, thereby safeguarding early vessel patency and acute gain. Subsequently a process of "decomposition" occurs, that results in the complete absorption of the scaffold. This reduces the risk of late complications, allowing the vessel to maintain its integrity and physiological function. This unique ability has attracted interest and nowadays several BRS are available. The aim of this review article is to describe the advances in the field, present the evidence from the preclinical and clinical evaluation of these devices, and provide an overview of the ongoing clinical trials that were designed to examine the effectiveness of BRS in the clinical setting.

No abstract is provided for this article.

Ttranscatheter aortic valve implantation (TAVI) is currently reserved for high surgical risk or inoperable patients. There are currently two types of valves being implanted, the Medtronic Corevalve and the Edwards SAPIEN device. In 2007, TAVI actually represented approximately 1.2% of all aortic valve procedures in Europe; this percentage increased to 6.5% in 2008. With an expectation of ~9000 TAVI procedures to be performed in 2009, TAVI may represent nearly 13% of all aortic valve procedures. It is forecasted that by 2012 transcatheter valve therapies will account for approximately 40% of the total heart valve procedures performed in Europe. One major limiting factor relates to procedural complications of TAVI. Conduction abnormalities and the need for permanent pacemaker, paravalvular aortic regurgitation, stroke and vascular complications have received particular attention. After implantation of the CoreValve device, the need for new permanent pacemaker has been reported to be in the range of 19–35%. In contrast, approximately 4–7% of patients are in need of permanent pacemaker after implantation of the Edwards device. The future and widespread adoption of TAVI will rely on a number of inter-related factors, including long-term durability and safety data, randomized controlled trials comparing TAVI with surgical aortic valve replacement and reimbursement for the technology.

Department of Medicine, Royal Postgraduate Medical School, and the Department of Thoracic Medicine, Brompton Hospital, London, England

Abstract Aims Despite the potential of alginate hydrogel intramyocardial injections in the treatment of heart failure (HF), minimally invasive implantation techniques remain scarce. This study evaluated the safety and feasibility of percutaneous transcatheter endocardial alginate hydrogel injection (TEAi), facilitated by novel implants and a dedicated catheter‐based device, in patients with HF with reduced ejection fraction (HFrEF). Methods and Results This first‐in‐human study enrolled HFrEF patients [New York Heart Association (NYHA) Class III–IV and left ventricular ejection fraction (LVEF) ≤35%]. The primary endpoint was the incidence of procedure‐ or device‐related serious adverse events (SADEs) at 30 days. Secondary endpoints included the device success rate, HF hospitalization at 6 months, and change from baseline to 6 months post‐procedure in the following parameters: LVEF as assessed by MRI; NYHA functional class; 6 min walk test distance (6MWT); the quality of life assessed by the Kansas City Cardiomyopathy Heart Failure Questionnaire (KCCQ); and serum N‐terminal prohormone of B‐type natriuretic peptide (NT‐proBNP) level. Pre‐ and post‐procedural biomechanical analysis was also evaluated. Ten patients successfully underwent TEAi with no SADEs at 30 days. There was one death and two HF hospitalizations at 6 months. At 6 months, LVEF improved from 17.7% ± 3.8% to 24.9% ± 11.2% ( P = 0.021), end‐systolic volume decreased from 297.5 ± 67.9 mL to 264.8 ± 101.4 mL ( P = 0.029), and KCCQ scores increased from 49.7 ± 3.9 to 79.0 ± 8.07 ( P = 0.008). No statistically significant changes were observed in end‐diastolic volume, NT‐proBNP and 6MWT at six months compared with the baseline. Biomechanical analysis revealed a reduction in peak left ventricular end‐diastolic wall stress (6.5 ± 1.1 kPa vs. 5.9 ± 1.3 kPa, P = 0.043). Conclusions TEAi is feasible and safe for the treatment of HFrEF, warranting further randomized, efficacy clinical trials.

Q-wave myocardial infarction (QWMI) comprises 2 entities. First, a clinically evident MI, which can occur spontaneously or be related to a coronary procedure. Second, silent MI which is incidentally detected on serial electrocardiographic (ECG) assessment. The prevalence of silent MI after percutaneous coronary intervention (PCI) in the drug-eluting stent era has not been fully investigated. The GLOBAL LEADERS is an all-comers multicenter trial which randomized 15,991 patients who underwent PCI to 2 antiplatelet treatment strategies. The primary end point was a composite of all-cause death or nonfatal new QWMI at 2-years follow-up. ECGs were collected at discharge, 3-month and 2-year visits, and analyzed by an independent ECG core laboratory following the Minnesota code. All new QWMI were further reviewed by a blinded independent cardiologist to identify a potential clinical correlate by reviewing clinical information. Of 15,968 participants, ECG information was complete in 14,829 (92.9%) at 2 years. A new QWMI was confirmed in 186 (1.16%) patients. Transient new Q-waves were observed in 28.5% (53 of 186) of them during the follow-up. The majority of new QWMI (78%, 146 of 186) were classified as silent MI due to the absence of a clinical correlate. Silent MI accounted for 22.1% (146 of 660) of all MI events. The prevalence of silent MI did not differ significantly between treatment strategies (experimental vs reference: 0.88% vs 0.98%, p = 0.5027). In conclusion, we document the prevalence of silent MI in an all-comers population undergoing PCI in this large-scale randomized trial.