Seismic Performance of Reinforced Concrete Columns Retrofitted with Hybrid Concrete Jackets Subjected to Combined Loadings

In the existing reinforced concrete columns where they are insufficient seismic details, critical failure mode such as shear failure can be observed under seismic loads. One strategy for the retrofitting of existing concrete columns is to use concrete jacketing. Concrete jacketing consists of a new concrete layer with longitudinal and transverse reinforcements, and can improve seismic resistance capacity. In this paper, a detail of concrete jacket that can be expected for easy construction and improved adhesion performance of longitudinal and transverse reinforcement was proposed. Additionally, a combined cyclic loading test was conducted to consider the seismic load with multiaxial characteristics. The concrete jacket details utilize three components: Steel Grid Reinforcement (SGR), Steel Wire Mesh (SWM), and Steel Fiber Non-Shrinkage Mortar (SFNM). One RC column with non-seismic details and two jacketed RC columns were fabricated to demonstrate the construction efficiencies and structural capacities of the jacketed columns. Two details of jacketed section were considered as variables. It was observed that the specimens retrofitted with concrete jacket resisted torsional load more than the un-retrofitted specimen in terms of crack and failure mode. The experimental results showed that the maximum load of retrofitted specimens was increased by more than 8 times compared to the un-retrofitted specimen, regardless of the jacket details. Newly designed concrete jacket effectively increased the strength. Compared with the un-retrofitted column, the columns retrofitted with the proposed details achieved significant increase in initial stiffness and energy dissipation.     

The Effects of Bond–Slip Laws on the Debonding Failure and Behavior of Flexural Strengthened RC Slabs in Hybrid FRP Retrofit Systems

The hybrid retrofit system using FRP and concrete overlay applied on the top of slabs has proven effective in strengthening and overcoming logistical constraints, compared with conventional strengthening techniques using externally bonded composite materials to the underside of the slabs. Nevertheless, the performance of retrofitted slabs is governed by debonding failure due to the low bond strength between CFRP and concrete overlay. Thus, this study investigates the behavior of flexural strengthened slabs with FRP retrofit systems and the effect of bond–slip laws on debonding failure. Firstly, two full-scale RC slabs with and without a retrofit system were tested in a four-point bending setup as the control specimens. Then, the same retrofitted slab was simulated by utilizing the commercial program ABAQUS. A sensitivity analysis was conducted to consider the influence of bond–slip laws to predict the failure mechanism of the retrofitted slabs based on load–deflection relationships. The results showed that the strengthened slab enhanced the load-carrying capacity by 59%, stiffness by 111%, and toughness by 29%. The initial stiffness of 0.1K₀ and maximum shear stress of 0.13τ_max, compared with the corresponding values of Neubauer’s and Rostasy’s bond–slip law, can be used to simulate the global response of the retrofitted slab validated by experiment results.     

Seismic Performance and Cost Analysis of UHPC Tall Buildings in UAE with Ductile Coupled Shear Walls

The superior mechanical characteristics of ultra-high-performance concrete (UHPC) have attracted the interest of many researchers worldwide. Researchers have attempted to perform comparative analyses on the behavior of UHPC versus conventional and high-strength concrete, with their aim being to gain more insights into the difference between different types of concrete. However, the current state-of-the-art revealed no direct comprehensive comparisons between their behaviors in ductile coupled shear walls under seismic loading. This paper explores a comprehensive side-by-side comparison in terms of seismic behavior and cost analysis for four 60-story archetype buildings. The reference building was designed using high-strength concrete with a strength of 60 MPa. The other three archetype variations incorporated three different UHPC grades: 150 MPa, 185 MPa, and 220 MPa. The plan configuration and the lateral force-resisting system (LFRS) were chosen according to the most common practice in the UAE. The main objective is to report the effect of UHPC on the LFRS (ductile coupled shear walls). Moreover, a simplified initial cost analysis (materials and labor) design was performed. The findings of this paper indicate that the use of UHPC is capable of improving the seismic performance behavior of the lateral system as well as reducing the total initial costs.     

Numerical Modelling of CFS Three-Story Strap-Braced Building under Shaking-Table Excitations

In recent research activities, shake-table tests were revealed to be useful to investigate the seismic behavior of cold-formed steel (CFS) buildings. However, testing full-scale buildings or reduced-scale prototypes is not always possible; indeed, predicting tools and numerical models could help designers to evaluate earthquake response. For this reason, numerical modelling of two strap-braced prototype buildings, recently tested on shake-table at University of Naples Federico II in cooperation with Lamieredil S.p.A. company, was developed. The models were validated trough the comparison between experimental and numerical results, in term of dynamic properties (fundamental period of vibration and modal shapes), peak roof drift ratios and peak inter-story drift ratios. Although dynamic properties of mock-ups were captured with accuracy by the developed models, the comparison highlighted the need to consider accumulation of damage and rocking phenomenon in the modelling to capture with good accuracy the seismic behavior of CFS strap-braced building, subjected to high intensity records.     

Mechanical Experiments on Concrete with Hybrid Fiber Reinforcement for Structural Rehabilitation

Reinforced concrete is used in the construction of bridges, buildings, retaining walls, roads, and other engineered structures. Due to seismic activities, a lot of structures develop seismic cracks. The rehabilitation of such structures is necessary for public safety. The overall aim of this research study was to produce a high-performance hybrid fiber-reinforced concrete (HPHFRC) with enhanced properties as compared to plain high-performance concrete and high-performance fiber-reinforced concrete (HPFRC) for the rehabilitation of bridges and buildings. Kevlar fibers (KF) and glass fibers (GF) with lengths of 35 mm and 25 mm, respectively, were added and hybridized to 1.5% by mass of cement to create hybrid fiber-reinforced concrete mixes. Eight mixes were cast in total. The compressive strength (f′_c), flexural strength (f_r), splitting tensile strength (f_s), and other mechanical properties, i.e., energy absorption and toughness index values, were enhanced in HPHFRC as compared to CM and HPFRC. It was found that the concrete hybridized with 0.75% KF and 0.75% GF (HF-G 0.75 K 0.75) had the most enhanced overall mechanical properties, illustrating its potential to be utilized in the rehabilitation of bridges and structures.     

Comparative Life Cycle Analysis of Concrete and Composite Bridges Varying Steel Recycling Ratio

Achieving sustainability is currently one of the main objectives, so a consensus between different environmental, social, and economic aspects is necessary. The construction sector is one of the main sectors responsible for environmental impacts worldwide. This paper proposes the life cycle assessment (LCA) and comparison of four bridge deck alternatives for different span lengths to determine which ones are the most sustainable solutions. The ReCiPe method is used to conduct the life cycle analysis, by means of which the impact value is obtained for every alternative and span length. The Ecoinvent 3.3 database has been used. The life cycle has been divided into four phases: manufacturing, construction, use and maintenance, and end of life. The associated uncertainties are considered, and the results are shown in both midpoint and endpoint approaches. The results of our research show that for span lengths less than 17 m, the best alternative is the prestressed concrete solid slab. For span lengths between 17 and 25 m, since the box-girder solution is not used, then the prestressed concrete lightened slab is the best alternative. For span lengths between 25 and 40 m, the best solution depends on the percentage of recycled structural steel. If this percentage is greater than 90%, then the best alternative is the composite box-girder bridge deck. However, if the percentage is lower, the cleanest alternative is the prestressed concrete box-girder deck. Therefore, the results show the importance of recycling and reusing structural steel in bridge deck designs.     

Structural Retrofitting of Corroded Reinforced Concrete Beams Using Bamboo Fiber Laminate

Corrosion creates a significant degradation mechanism in reinforced concrete (RC) structures, which would require a high cost of maintenance and repair in affected buildings. However, as the cost of repairing corrosion-damaged structures is high, it is therefore pertinent to develop alternative eco-friendly and sustainable methods. In this study, structural retrofitting of corroded reinforced concrete beams was performed using bamboo fiber laminate. Three reinforced normal weight concrete beams were produced, two of which were exposed to laboratory simulated corrosion medium, and the remaining one sample served as control. Upon completion of the corrosion cycle, one of the two corroded beams was retrofitted externally with a prefabricated bamboo fiber laminate by bonding the laminate to the beam surface with the aid of an epoxy resin. The three beams were subjected to loading on a four-point ultimate testing machine, and the loads with corresponding deflections were recorded through the entire load cycle of the beams. Finally, the mass loss of embedded steel reinforcements was determined to measure the effect of corrosion on the beams and the steel. The result showed that corroded beams strengthened with bamboo laminates increase the bearing capacity. Using a single bamboo laminate in the tensile region of the corroded beam increased the ultimate load capacity of the beam up to 21.1% than the corroded beam without retrofit. It was demonstrated in this study that the use of bamboo fiber polymer for strengthening destressed RC beams is a more sustainable approach than the conventional synthetic fibers.     

Seismic Performance Evaluation of RC Columns Retrofitted by 3D Textile Reinforced Mortars

The paper investigates the seismic performance of rectangular RC columns retrofitted by a newly developed 3D Textile Reinforced Mortar (TRM) panel. The 3D-TRM used in this study consists of two components: self-leveling mortar and 3D textiles. Firstly, the flexural capacity of the 3D-TRM panel was investigated through the four-point flexural test. Secondly, a total of five specimens were constructed and experimentally investigated through static cyclic loading tests with constant axial load. One specimen was a non-seismically designed column without any retrofit, while the others were strengthened with either the 3D-TRM panel or conventional Fiber Reinforced Polymer (FRP) sheets. Experimental results in terms of hysteretic behavior, ductility ratio, and energy dissipation are investigated and compared with the cases of specimens with conventional retrofitting methods and without any retrofit. The maximum lateral force, ductility, stiffness degradation, and energy dissipation of RC columns with 3D-TRM panels were significantly improved compared with the conventional RC column. Therefore, it is concluded that the proposed retrofitting method can improve the seismic performance of non-conforming RC columns.     

Levosimendan in daily intensive care practice--the experience of 15 centers. Background, methods and organization of the PORTLAND study.

INTRODUCTION: The LIDO and RUSSLAN trials showed that levosimendan was well tolerated and had a stronger hemodynamic effect than dobutamine and a positive impact on prognosis. There are, however, few data regarding its effectiveness and safety when used in an everyday clinical setting. OBJECTIVE: To test the hypothesis that in day-to-day practice conditions levosimendan is both effective and safe for the treatment of decompensated heart failure (HF). This primary combined endpoint of effectiveness and safety was evaluated at 24 hours and 5 days after the beginning of the treatment. DESIGN: Prospective, multicenter, nonrandomized clinical trial with evaluations at baseline, 24 hours, 5 days, and 3 and 6 months. Follow-up for 6 months. SETTING: The intensive care units of 15 cardiology or internal medicine departments. PATIENTS: 129 consecutive patients requiring inotropes due to decompensated systolic HF despite maximally tolerated oral therapy. Intervention: 24-hour infusion of levosimendan via a central or peripheral vein. MEASUREMENTS AND EVALUATION OF RESULTS: 1. Monitoring: Continuous ECG monitoring, non-invasive blood pressure, urinary output, oximetry. Invasive monitoring was not required. 2. Follow-up. Baseline evaluation: history, physical examination, ECG, 2D echocardiogram, hemogram, ionogram, liver and kidney function. 24-hour and 5-day evaluations: symptoms, physical examination, recording of medical therapy and previous 24-hour urinary output, ECG, hemogram, ionogram, liver and kidney function, and evaluation of arrhythmic episodes and heart rate and blood pressure trends in previous 24 hours. 3- and 6-month evaluations: number of hospital admissions and length of hospital stay due to HF, and mortality. 3. Evaluation of primary endpoint. EFFECTIVENESS: assessed by a clinical score including 2 subjective parameters (1. NYHA functional class, 2. patient self-evaluation symptom class) and 6 objective parameters (3. body weight, 4. pulmonary congestion, 5. previous 24-hour diuresis, 6. serum creatinine, 7. oral HF medication, 8. intravenous HF medication). Definition of clinical effectiveness: improvement in > or = 1 subjective parameters plus improvement in > or = 1 objective parameters, with all other parameters unchanged. Safety: The therapy was judged safe in the absence of any serious adverse event with a probable or undetermined causal relationship with levosimendan. Primary endpoint evaluation: Patients reached the primary endpoint when levosimendan was both effective and safe according to the above definitions.     

Radiofrequency Modification of the Atrioventricular Node in Patients with Chronic Atrial Fibrillation:

RF Modification of AVN in AF. Introduction : We compared, in a prospective and randomized fashion with a cross-over design, the anterior and posterior approaches to radiofrequency (RF) modification of the AV node in patients with chronic atrial fibrillation.
Methods and Results : Thirty-three patients were randomized to receive first an anterior (group I) or posterior (group II) approach for RF modification of AV nodal conduction. Patients who did not fill the endpoint ventricular rate (< 90 beats/min) were crossed over to the alternative approach. After the anterior approach in group I patients, mean ventricular rate was significantly lower than in group II patients after the posterior approach (79.6 ± 18.8 beats/min vs 110.8 ± 16.2 beats/min, P < 0.001). In group I, 14 (82%) of 17 patients fulfilled the endpoint, 1 (6%) had complete AV block, and 2 (12%) were crossed over to the posterior approach fulfilling the endpoint. In group II, 4 (25%) of 16 patients fulfilled the endpoint. No transient or permanent high-degree AV block was observed. Among the 12 patients who were crossed over to the anterior approach, 8 fulfilled the endpoint, whereas 4 had permanent high-degree AV block. RF ablation carried out only in the anterior region was safer than a stepwise approach (6% vs 33% incidence of AV block), even though the difference did not reach statistical significance (P = 0.09).
Conclusion : Posterior AV nodal modification is less effective but safer than anterior AV nodal modification. However, to reduce the incidence of AV block, the anterior approach is preferable to a stepwise approach from the posterior to the anterior zone.     

Geotechnical Seismic Isolation System Based on Rubber-Sand Mixtures for Rural Residence Buildings: Shaking Table Test

The anti-seismic problem of rural residential buildings is the weak link of seismic retrofitting in China. Recently, geotechnical seismic isolation (GSI) technology based on rubber–sand mixtures (GSI–RSM) using rubber–sand mixtures (RSM) between the structural foundation and the foundation soil has been proven to have the possibility of potential applications in rural residential buildings. Many theoretical studies exist on the effectiveness of seismic isolation of the GSI–RSM system, but few studies on either the seismic response test of model buildings placed on the RSM layer or the large-scale shaking table test exist. Therefore, this study considers a large shaking table test performed on a 1/4 single-story masonry structure model with and without a GSI–RSM system by selecting a standard input ground motion and varying input acceleration amplitudes. The test results show that the GSI–RSM system can reduce the seismic response of superstructures. The isolation effect of the GSI–RSM system is low in small earthquakes and increases with increasing earthquake magnitude. Overall, the RSM layer can filter part of the high-frequency components of the earthquake to transmit to the superstructure and consume more seismic energy by generating friction slip in the interaction with the structural foundation.     

A double-blind multicenter comparison of the efficacy and safety ofsaruplase andurokinase in thetreatment ofacutemyocardialinfarction: Report of the SUTAMI study group

Background: Urokinase or two-chain urokinasetype plasminogen activator has been shown to be effective in the treatment of acute myocardial infarction. Its parent molecule, single-chain urokinase-type plasminogen activator (scu-PA), unlike urokinase, can selectively activate fibrinbound plasminogen. The induced clot lysis is amplified by plasmin-triggered conversion of scu-PA to urokinase and by further plasmin generation. The aim of our study was to compare the efficacy and safety of recombinant unglycosylated scu-PA, or saruplase, and urokinase at doses considered optimal in patients with acute myocardial infarction within 6 hours of onset of pain. Methods and results: In a double-blind trial 543 patients were randomized to saruplase (20 mg bolus + 60 mg/hr) or urokinase (1.5 million unit bolus + 1.5 million units/hr). Primary endpoint: The patency rates at 24–72 hours were 75.4% (95% CI 70.3–80.5%) for saruplase and 74.2% (95% CI 69.0–79.4%;P=0.77) for urokinase. Secondary endpoint: The incidence of bleeding events in both groups was 10.7%. There were three hemorrhagic strokes in the saruplase group (ns). Other efficacy and safety evaluations: Apart from the generation of more fibrinogen degradation products under saruplase, the changes in hemostatic parameters did not differ. Hospital mortality was 4.4% for saruplase and 8.1% for urokinase. This nonsignificant difference was maintained for 1 year. Conclusion: The efficacy and safety of saruplase and urokinase in the regimens used are very similar.     

Accuracy of Seismic Response Evaluation of Two-Dimensional Analysis Model with Rigid Joints for RC Frame Buildings

Three- or two-dimensional (2D) numerical models are used for the evaluation of the seismic performance of reinforced concrete (RC) buildings. This study examines a 2D numerical model for a specimen used in a full-scale four-story RC shaking-table test and evaluates the accuracy of the seismic response of the 2D numerical model, which is composed of a square fiber section model for the columns, a T-shape fiber section model for the beam and slab, and a rigid joint model for the beam–column joint. A parametric analysis of the effective slab width is performed to analyze its effects on the modal shape and natural period. The results suggest that the primary natural period of the considered model is almost identical to that associated with the experimental results. The applicability of the 2D numerical model for estimating the seismic response of the structure is established. By comparing the results of the seismic analysis and the experiment in the 50% amplitude of the JMA-Kobe wave, which corresponds to slightly exceeding VII on the modified Mercalli intensity scale, the root-mean-square percentage error of the 2D numerical model is 1.03% for the floor acceleration and 4.7% for the inter-story drift. Thus, the analytical model used in this study has sufficient accuracy in evaluating the seismic performance of buildings constructed in regions with a maximum seismic intensity of VII.     

Application of Coal Gangue as a Coarse Aggregate in Green Concrete Production: A Review

Among the techniques for converting stacked coal gangue to reusable material, one of the most effective ways is to use coal gangue as a coarse aggregate in green concrete productions. The physical and chemical properties of rock and spontaneous-combustion coal gangue are generally suitable for being used as a coarse aggregate in green concrete. Coal gangue concrete is not recommended to be used in subsurface structures, as its water absorption law would be changed under a large replacement ratio. The mechanical performance of coal gangue concrete is degraded by raising the replacement ratio. Over-low and -high concrete grades are not suggested to be used as coal gangue aggregate, unless extra admixtures or specific methods are used. The influence of coal gangue on the durability of coal gangue concrete is remarkable, resulting from the porous structure of coal gangue that provides more transmission channels for air and liquid in concrete, but is beneficial for thermal insulation. The usage of coal gangue in structural concrete members is still limited. The mechanical behavior of some structural members using coal gangue concrete has been reported. Among them, concrete filled steel tubes are a preferable configuration for using coal gangue concrete, regarding both the mechanical and durability performance.     

The Seismic Performance of New Self-Centering Beam-Column Joints of Conventional Island Main Buildings in Nuclear Power Plants

In order to improve the deformation energy consumption and self-centering ability of reinforced concrete (RC) frame beam-column joints for main buildings of conventional islands in nuclear power plants, a new type of self-centering joint equipped with super-elastic shape memory alloy (SMA) bars and a steel plate as kernel components in the core area of the joint is proposed in this study. Four 1/5-scale frame joints were designed and manufactured, including two contrast joints (a normal reinforced concrete joint and a concrete joint that replaces steel bars with SMA bars) and two new model joints with different SMA reinforcement ratios. Subsequently, the residual deformation, energy dissipation capacity, stiffness degradation and self-centering performance of the novel frame joints were studied through a low-frequency cyclic loading test. Finally, based on the OpenSees finite element software platform, an effective numerical model of the new joint was established and verified. On this basis, varying two main parameters, the SMA reinforcement ratio and the axial compression ratio, a simulation was systematically conducted to demonstrate the effectiveness of the proposed joint in seismic performance. The results show that replacing ordinary steel bars in the beam with SMA bars not only greatly reduces the bearing capacity and stiffness of the joint, but also makes the failure mode of the joint brittle. The construction of a new type of joint with consideration of the SMA reinforcement and the steel plate can improve the bearing capacity, delay the stiffness degradation and improve the ductility and self-centering capability of the joints. Within a certain range, increasing the ratio of the SMA bars can further improve the ultimate bearing capacity and energy dissipation capacity of the new joint. Increasing or decreasing the axial compression ratio of column ends has little effect on the overall seismic performance of new joints.     

Megakaryoblastic crisis of chronic myelogenous leukemia cytological and clinical studies in three cases

Diagnostic significance of the megakaryocyte markers and clinical findings were evaluated in three cases with chronic myelogenous leukemia in megakaryoblastic crisis. Platelet peroxidase (PPO), glycoprotein IIb/IIIa, Ib, von Willebrand factor antigen (vWF: Ag) and demarcation membrane system (DMS) were examined as the megakaryocyte markers. Blast phenotypes were as follows: PPO- IIb/IIIa+ vWF: Ag+ DMS+ in Case 1, PPO+ IIb/IIIa +/- Ib- vWF: Ag +/- in Case 2 and PPO+ IIb/IIIa+ vWF: Ag +/- DMS +/- in Case 3 (-: 0% +/-: less than 10% +: greater than or equal to 10%). In Cases 1 and 3, no markers other than those for the megakaryocyte lineage were detected, but myeloperoxidase-positive blasts coexisted with PPO-positive megakaryoblasts in Case 2. Megakaryoblast phenotypes and involvement of other lineages were much different in each case. Therefore, marker study for cytological diagnosis should be performed in consideration of lineage heterogeneity. As to the clinical findings, no clear features common to the three cases were present. However, multiple osteolytic lesions were demonstrated on bone survey in Case 1 and considered to be caused by the proliferation of megakaryoblasts.     

Adult age differences in spatial memory: effects of distinctiveness and repeated experience

Young (mean age = 25.0) and elderly (mean age = 65.0) women's memory for buildings in a large model town was assessed. Participants viewed and constructed the town on two trials. Building distinctiveness was manipulated by showing differentiated buildings with unique physical and functional properties (e.g., school, gas station), or nondifferentiated buildings that were not functionally distinct and only somewhat physically distinct (e.g., red cube-like structure with curved roof, yellow cube-like structure with flat roof). Building distinctiveness was further manipulated by verbally labeling or not labeling each building type. On Trial 1 young adults were more accurate than elderly adults only on the differentiated buildings; on Trial 2 this age difference was evident on differentiated and nondifferentiated buildings. Verbal labeling did not significantly affect construction accuracy. It was concluded that age differences occurred because elderly adults have more difficulty utilizing encoding strategies than young adults.     

Therapy after single oral agent failure: adding a second oral agent or an insulin mixture?

AIM: to compare the glycemic response to an insulin lispro mixture (25% insulin lispro and 75% NPL) twice daily plus metformin (Mix25+M) with glibenclamide plus metformin (G+M), in patients with type 2 diabetes inadequately controlled with a single oral agent. METHODS: 597 patients treated in a randomized, open-label, 16-week parallel study. Variables evaluated: hemoglobin A1C (A1C), patient symptoms, hypoglycemia rate (episodes/patient/30 days), and incidence (% patients experiencing > or =1 episode). For a subset of patients (N=120), fasting, 1-h, and 2-h postprandial plasma glucose (FPG, 1-h ppPG, 2-h ppPG) in response to a standardized test meal (STM) and self-monitored blood glucose (BG) profiles were measured. RESULTS: improved A1C at endpoint for both groups, and A1C changes from baseline to endpoint were not significantly different between treatments (Mix25+M, -1.87+/-1.35% vs. G+M, -1.98+/-1.28%; p=0.288). Among patients completing STM; endpoint 2-h ppPG was significantly lower with Mix25+M (9.05+/-3.32 mmol/l vs. 12.31+/-3.65 mmol/l; p<0.001), as was 2-h ppPG excursion (2-h ppPGex)(0.38+/-3.23 mmol/l vs. 2.88+/-1.98 mmol/l; p<0.001). Percentage of patients achieving postprandial BG targets (<10 mmol/l) at endpoint was significantly greater with Mix25+M (80% vs. 48%; p<0.001). Although, overall hypoglycemia rates were similar, percentage of patients experiencing and rate of nocturnal hypoglycemia was less with Mix25+M (1% vs. 5%; p<0.01, and 0.01 vs. 0.08 episodes/pt/30 d; p=0.007). Patients reported less polyuria with Mix25+M (p<0.001). CONCLUSION: in patients with type 2 diabetes failing on metformin or a sulfonylurea, Mix25+M provided similar overall glycemic control, lower ppPG, reduced nocturnal hypoglycemia, and fewer hyperglycemic symptoms compared to G+M.     

Low-molecular-weight heparins in acute myocardial infarction: rationale and results of a pilot study

BACKGROUND: Antithrombotic adjuncts to fibrinolytic drugs for acute myocardial infarction increase the rate and speed of infarct artery recanalization. HYPOTHESIS: A low-molecular-weight heparin might be preferable to unfractionated heparin for this indication, as it has been shown to be in several other thrombus-related vascular disorders. METHODS: We performed a pilot study in 20 patients, all receiving aspirin and recombinant tissue plasminogen activator. Randomization was to standard dose intravenous unfractionated heparin or enoxaparin (the first dose given intravenously and followed by a subcutaneous administration). The endpoint was stability of anticoagulant effect. RESULTS: Enoxaparin produced stable therapeutic anti-Xa levels with minimal effect on activated partial thromboplastin times. Unfractionated heparin produced wide swings of these parameters, often outside desired levels. CONCLUSIONS: Enoxaparin may be a better antithrombotic agent than conventional unfractionated heparin when used in conjunction with fibrinolytics.     

Impact of nicorandil to prevent reperfusion injury in patients with acute myocardial infarction: Sigmart Multicenter Angioplasty Revascularization Trial (SMART).

BACKGROUND: Nicorandil in conjunction with percutaneous coronary intervention (PCI) has been reported to reduce reperfusion injury events and improve cardiac function in patients with acute myocardial infarction (AMI). This multicenter study was undertaken to determine the effectiveness and optimal administration of nicorandil in AMI patients. METHODS AND RESULTS: Ninety-two patients with first AMI were randomly assigned to 1 of 3 groups: intracoronary administration of nicorandil (Group A), combined intravenous and intracoronary administration of nicorandil (Group B), and no nicorandil administration (Group C). The primary endpoint was a composite of the incidence of reperfusion-induced arrhythmia, chest pain, and no-reflow/slow-reflow. The secondary endpoint was the combined rate of improvement in the Thrombolysis in Myocardial Infarction frame count (cTFC) and ST resolution (STR). A significant difference was observed in the primary endpoint for Group B as compared with Group C (p<0.05). In the meantime, a significant improvement was shown in the secondary endpoint for Group B compared with Group C (p=0.04 and 0.006 for cTFC and STR, respectively). CONCLUSIONS: Combined intravenous and intracoronary administration of nicorandil reduces reperfusion injury during PCI and improves the cTFC and STR in AMI, and appears to be preferable to intracoronary administration alone.