Benefits and Risks of Extended Duration Dual Antiplatelet Therapy After PCI in Patients With and Without Acute Myocardial Infarction

BACKGROUND The benefits and risks of prolonged dual antiplatelet therapy may be different for patients with acute myocardial infarction (MI) compared with more stable presentations. OBJECTIVES This study sought to assess the benefits and risks of 30 versus 12 months of dual antiplatelet therapy among patients undergoing coronary stent implantation with and without MI. METHODS The Dual Antiplatelet Therapy Study, a randomized double-blind, placebo-controlled trial, compared 30 versus 12 months of dual antiplatelet therapy after coronary stenting. The effect of continued thienopyridine on ischemic and bleeding events among patients initially presenting with versus without MI was assessed. The coprimary endpoints were definite or probable stent thrombosis and major adverse cardiovascular and cerebrovascular events (MACCE). The primary safety endpoint was GUSTO (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Arteries) moderate or severe bleeding. RESULTS Of 11,648 randomized patients (9,961 treated with drug-eluting stents, 1,687 with bare-metal stents), 30.7% presented with MI. Between 12 and 30 months, continued thienopyridine reduced stent thrombosis compared with placebo in patients with and without MI at presentation (MI group, 0.5% vs. 1.9%, p < 0.001; no MI group, 0.4% vs. 1.1%, p < 0.001; interaction p = 0.69). The reduction in MACCE for continued thienopyridine was greater for patients with MI (3.9% vs. 6.8%; p < 0.001) compared with those with no MI (4.4% vs. 5.3%; p = 0.08; interaction p = 0.03). In both groups, continued thienopyridine reduced MI (2.2% vs. 5.2%, p < 0.001 for MI; 2.1% vs. 3.5%, p < 0.001 for no MI; interaction p = 0.15) but increased bleeding (1.9% vs. 0.8%, p = 0.005 for MI; 2.6% vs. 1.7%, p = 0.007 for no MI; interaction p = 0.21). CONCLUSIONS Compared with 12 months of therapy, 30 months of dual antiplatelet therapy reduced the risk of stent thrombosis and MI in patients with and without MI, and increased bleeding. (The Dual Antiplatelet Therapy Study [The DAPT Study]; NCT00977938).

Antiplatelet therapy duration following bare metal or drug-eluting coronary stents: the dual antiplatelet therapy randomized clinical trial

IMPORTANCE Despite antirestenotic efficacy of coronary drug-eluting stents (DES) compared with bare metal stents (BMS), the relative risk of stent thrombosis and adverse cardiovascular events is unclear. Although dual antiplatelet therapy (DAPT) beyond 1 year provides ischemic event protection after DES, ischemic event risk is perceived to be less after BMS, and the appropriate duration of DAPT after BMS is unknown. OBJECTIVE To compare (1) rates of stent thrombosis and major adverse cardiac and cerebrovascular events (MACCE; composite of death, myocardial infarction, or stroke) after 30 vs 12 months of thienopyridine in patients treated with BMS taking aspirin and (2) treatment duration effect within the combined cohorts of randomized patients treated with DES or BMS as prespecified secondary analyses. DESIGN, SETTING, AND PARTICIPANTS International, multicenter, randomized, double-blinded, placebo-controlled trial comparing extended (30-months) thienopyridine vs placebo in patients taking aspirin who completed 12 months of DAPT without bleeding or ischemic events after receiving stents. The study was initiated in August 2009 with the last follow-up visit in May 2014. INTERVENTIONS Continued thienopyridine or placebo at months 12 through 30 after stent placement, in 11,648 randomized patients treated with aspirin, of whom 1687 received BMS and 9961 DES. MAIN OUTCOMES AND MEASURES Stent thrombosis, MACCE, and moderate or severe bleeding. RESULTS Among 1687 patients treated with BMS who were randomized to continued thienopyridine vs placebo, rates of stent thrombosis were 0.5% vs 1.11% (n = 4 vs 9; hazard ratio [HR], 0.49; 95% CI, 0.15-1.64; P = .24), rates of MACCE were 4.04% vs 4.69% (n = 33 vs 38; HR, 0.92; 95% CI, 0.57-1.47; P = .72), and rates of moderate/severe bleeding were 2.03% vs 0.90% (n = 16 vs 7; P = .07), respectively. Among all 11,648 randomized patients (both BMS and DES), stent thrombosis rates were 0.41% vs 1.32% (n = 23 vs 74; HR, 0.31; 95% CI, 0.19-0.50; P < .001), rates of MACCE were 4.29% vs 5.74% (n = 244 vs 323; HR, 0.73; 95% CI, 0.62-0.87; P < .001), and rates of moderate/severe bleeding were 2.45% vs 1.47% (n = 135 vs 80; P < .001). CONCLUSIONS AND RELEVANCE Among patients undergoing coronary stent placement with BMS and who tolerated 12 months of thienopyridine, continuing thienopyridine for an additional 18 months compared with placebo did not result in statistically significant differences in rates of stent thrombosis, MACCE, or moderate or severe bleeding. However, the BMS subset may have been underpowered to identify such differences, and further trials are suggested. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00977938.

Dual Role of Mesenchymal Stem Cells Allows for Microvascularized Bone Tissue-Like Environments in PEG Hydrogels.

In vitro engineered tissues which recapitulate functional and morphological properties of bone marrow and bone tissue will be desirable to study bone regeneration under fully controlled conditions. Among the key players in the initial phase of bone regeneration are mesenchymal stem cells (MSCs) and endothelial cells (ECs) that are in close contact in many tissues. Additionally, the generation of tissue constructs for in vivo transplantations has included the use of ECs since insufficient vascularization is one of the bottlenecks in (bone) tissue engineering. Here, 3D cocultures of human bone marrow derived MSCs (hBM-MSCs) and human umbilical vein endothelial cells (HUVECs) in synthetic biomimetic poly(ethylene glycol) (PEG)-based matrices are directed toward vascularized bone mimicking tissue constructs. In this environment, bone morphogenetic protein-2 (BMP-2) or fibroblast growth factor-2 (FGF-2) promotes the formation of vascular networks. However, while osteogenic differentiation is achieved with BMP-2, the treatment with FGF-2 suppressed osteogenic differentiation. Thus, this study shows that cocultures of hBM-MSCs and HUVECs in biological inert PEG matrices can be directed toward bone and bone marrow-like 3D tissue constructs.

Ultra-low-dose dual-source CT coronary angiography with high pitch: diagnostic yield of a volumetric planning scan and effects on dose reduction and imaging strategy

OBJECTIVE To evaluate the role of an ultra-low-dose dual-source CT coronary angiography (CTCA) scan with high pitch for delimiting the range of the subsequent standard CTCA scan. METHODS 30 patients with an indication for CTCA were prospectively examined using a two-scan dual-source CTCA protocol (2.0 × 64.0 × 0.6 mm; pitch, 3.4; rotation time of 280 ms; 100 kV): Scan 1 was acquired with one-fifth of the tube current suggested by the automatic exposure control software [CareDose 4D™ (Siemens Healthcare, Erlangen, Germany) using 100 kV and 370 mAs as a reference] with the scan length from the tracheal bifurcation to the diaphragmatic border. Scan 2 was acquired with standard tube current extending with reduced scan length based on Scan 1. Nine central coronary artery segments were analysed qualitatively on both scans. RESULTS Scan 2 (105.1 ± 10.1 mm) was significantly shorter than Scan 1 (127.0 ± 8.7 mm). Image quality scores were significantly better for Scan 2. However, in 5 of 6 (83%) patients with stenotic coronary artery disease, a stenosis was already detected in Scan 1 and in 13 of 24 (54%) patients with non-stenotic coronary arteries, a stenosis was already excluded by Scan 1. Using Scan 2 as reference, the positive- and negative-predictive value of Scan 1 was 83% (5 of 6 patients) and 100% (13 of 13 patients), respectively. CONCLUSION An ultra-low-dose CTCA planning scan enables a reliable scan length reduction of the following standard CTCA scan and allows for correct diagnosis in a substantial proportion of patients. ADVANCES IN KNOWLEDGE Further dose reductions are possible owing to a change in the individual patient's imaging strategy as a prior ultra-low-dose CTCA scan may already rule out the presence of a stenosis or may lead to a direct transferal to an invasive catheter procedure.

Metal Artifact Reduction in Pelvic Computed Tomography With Hip Prostheses: Comparison of Virtual Monoenergetic Extrapolations From Dual-Energy Computed Tomography and an Iterative Metal Artifact Reduction Algorithm in a Phantom Study.

OBJECTIVE The aim of this study was to directly compare metal artifact reduction (MAR) of virtual monoenergetic extrapolations (VMEs) from dual-energy computed tomography (CT) with iterative MAR (iMAR) from single energy in pelvic CT with hip prostheses. MATERIALS AND METHODS A human pelvis phantom with unilateral or bilateral metal inserts of different material (steel and titanium) was scanned with third-generation dual-source CT using single (120 kVp) and dual-energy (100/150 kVp) at similar radiation dose (CT dose index, 7.15 mGy). Three image series for each phantom configuration were reconstructed: uncorrected, VME, and iMAR. Two independent, blinded radiologists assessed image quality quantitatively (noise and attenuation) and subjectively (5-point Likert scale). Intraclass correlation coefficients (ICCs) and Cohen κ were calculated to evaluate interreader agreements. Repeated measures analysis of variance and Friedman test were used to compare quantitative and qualitative image quality. Post hoc testing was performed using a corrected (Bonferroni) P < 0.017. RESULTS Agreements between readers were high for noise (all, ICC ≥ 0.975) and attenuation (all, ICC ≥ 0.986); agreements for qualitative assessment were good to perfect (all, κ ≥ 0.678). Compared with uncorrected images, VME showed significant noise reduction in the phantom with titanium only (P < 0.017), and iMAR showed significantly lower noise in all regions and phantom configurations (all, P < 0.017). In all phantom configurations, deviations of attenuation were smallest in images reconstructed with iMAR. For VME, there was a tendency toward higher subjective image quality in phantoms with titanium compared with uncorrected images, however, without reaching statistical significance (P > 0.017). Subjective image quality was rated significantly higher for images reconstructed with iMAR than for uncorrected images in all phantom configurations (all, P < 0.017). CONCLUSIONS Iterative MAR showed better MAR capabilities than VME in settings with bilateral hip prosthesis or unilateral steel prosthesis. In settings with unilateral hip prosthesis made of titanium, VME and iMAR performed similarly well.

Incremental Value of the CRUSADE, ACUITY, and HAS-BLED Risk Scores for the Prediction of Hemorrhagic Events After Coronary Stent Implantation in Patients Undergoing Long or Short Duration of Dual Antiplatelet Therapy

BACKGROUND Multiple scores have been proposed to stratify bleeding risk, but their value to guide dual antiplatelet therapy duration has never been appraised. We compared the performance of the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA Guidelines), ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy), and HAS-BLED (Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly) scores in 1946 patients recruited in the Prolonging Dual Antiplatelet Treatment After Grading Stent-Induced Intimal Hyperplasia Study (PRODIGY) and assessed hemorrhagic and ischemic events in the 24- and 6-month dual antiplatelet therapy groups. METHODS AND RESULTS Bleeding score performance was assessed with a Cox regression model and C statistics. Discriminative and reclassification power was assessed with net reclassification improvement and integrated discrimination improvement. The C statistic was similar between the CRUSADE score (area under the curve 0.71) and ACUITY (area under the curve 0.68), and higher than HAS-BLED (area under the curve 0.63). CRUSADE, but not ACUITY, improved reclassification (net reclassification index 0.39, P=0.005) and discrimination (integrated discrimination improvement index 0.0083, P=0.021) of major bleeding compared with HAS-BLED. Major bleeding and transfusions were higher in the 24- versus 6-month dual antiplatelet therapy groups in patients with a CRUSADE score >40 (hazard ratio for bleeding 2.69, P=0.035; hazard ratio for transfusions 4.65, P=0.009) but not in those with CRUSADE score ≤40 (hazard ratio for bleeding 1.50, P=0.25; hazard ratio for transfusions 1.37, P=0.44), with positive interaction (Pint=0.05 and Pint=0.01, respectively). The number of patients with high CRUSADE scores needed to treat for harm for major bleeding and transfusion were 17 and 15, respectively, with 24-month rather than 6-month dual antiplatelet therapy; corresponding figures in the overall population were 67 and 71, respectively. CONCLUSIONS Our analysis suggests that the CRUSADE score predicts major bleeding similarly to ACUITY and better than HAS BLED in an all-comer population with percutaneous coronary intervention and potentially identifies patients at higher risk of hemorrhagic complications when treated with a long-term dual antiplatelet therapy regimen. CLINICAL TRIAL REGISTRATION URL: http://clinicaltrials.gov. Unique identifier: NCT00611286.

Dual-Domain Filtering

We propose dual-domain filtering, an image processing paradigm that couples spatial domain with frequency domain filtering. Our dual-domain defined filter removes artifacts like residual noise of other image denoising methods and compression artifacts. Moreover, iterating the filter achieves state-of-the-art image denoising results, but with a much simpler algorithm than competing approaches. The simplicity and versatility of the dual-domain filter makes it an attractive tool for image processing.

Cerebellar Pathology Does Not Impair Performance on Identification or Categorization Tasks

In comparison to the basal ganglia, prefrontal cortex, and medial temporal lobes, the cerebellum has been absent from recent research on the neural substrates of categorization and identification, two prominent tasks in the learning and memory literature. To investigate the contribution of the cerebellum to these tasks, we tested patients with cerebellar pathology (seven with bilateral degeneration, six with unilateral lesions, and two with midline damage) on rule-based and information-integration categorization tasks and an identification task. In rule-based tasks, it is assumed that participants learn the categories through an explicit reasoning process. In information-integration tasks, optimal performance requires the integration of information from multiple stimulus dimensions, and participants are typically unaware of the decision strategy. The identification task, in contrast, required participants to learn arbitrary, color-word associations. The cerebellar patients performed similar to matched controls on all three tasks and performance did not vary with the extent of cerebellar pathology. Although the interpretation of these null results requires caution, these data contribute to the current debate on cerebellar contributions to cognition by providing boundary conditions on understanding the neural substrates of categorization and identification, and help define the functional domain of the cerebellum in learning and memory.

Nonparametric Measures of Capacity Utilization: A Dual Approach

This paper develops a nonparametric method of obtaining the minimum of the long run average cost curve of a firm to define its capacity output. This provides a benchmark for measuring of capacity utilization at the observed output level of the firm. In the case of long run constant returns to scale, the minimum of the short run average cost curve is determined to measure short run capacity utilization. An empirical application measures yearly rates of capacity utilization in U.S. manufacturing over the period 1968-1998. Nonparametric determination of the short run average cost curve under variable returns to scale using an iterative search procedure is described in an appendix to this paper.

Assessment of English Language Learners Seeking a Graduate Degree in Speech Language Pathology

A shortage of bilingual/bicultural speech language pathologists may reflect a problem with recruitment and retention of bilingual/bicultural students. The purpose of the present study was to survey graduate training programs in speech language pathology to determine typical policies and practices concerning students who apply and are admitted as ELLs. With a growing number of ELL children needing services from a bilingual SLP, it seems that little is being done to address the issue. The problem may be with the reluctance of programs to not only accept ELL students, but there also seems to be a disinclination for any sort of training program to be established for these ELL students. Clinic directors were asked to complete a survey about ELLs seeking clinical training in speech language pathology. In particular, we were interested in obtaining information about whether clinical training programs a) provided opportunities for ELL to participate in clinic, b) assessed the English skills of these students, and c) provided remediation if these students English skills were judged to be less than proficient.

Bayesian dual threshold design with Dirichlet distribution: An alternative way to frequentist multi-stage phase II designs in oncology

Many phase II clinical studies in oncology use two-stage frequentist design such as Simon's optimal design. However, they have a common logistical problem regarding the patient accrual at the interim. Strictly speaking, patient accrual at the end of the first stage may have to be suspended until all patients have events, success or failure. For example, when the study endpoint is six-month progression free survival, patient accrual has to be stopped until all outcomes from stage I is observed. However, study investigators may have concern when accrual is suspended after the first stage due to the loss of accrual momentum during this hiatus. We propose a two-stage phase II design that resolves the patient accrual problem due to an interim analysis, and it can be used as an alternative way to frequentist two-stage phase II studies in oncology. ^

A dual oxidase generates a protective oxidative burst during infection in C. elegans

Caenorhabditis elegans has recently been developed as a model system to study both pathogen virulence mechanisms and host defense responses. We have shown that C. elegans produces reactive oxygen species (ROS) in response to exposure to the important Gram-positive, noscomial pathogen, Enterococcus faecalis. We have also shown evidence of oxidative stress and upregulation of stress response after exposure to the pathogen. As in mammalian systems, this work shows that production of ROS for innate immune functions occurs via an NADPH oxidase. Specifically, reducing expression of a dual oxidase, Ce-duox1/BLI-3 causes a decrease in ROS production in response to E. faecalis. We also present evidence that reduction of expression of Ce-duox1/BLI-3 increases susceptibility to this pathogen, specifically when expression is reduced in the intestine and the hypodermis. This dual oxidase has previously been localized to the hypodermis, but we show that it is additionally localized to the intestine of C. elegans. To further demonstrate the protective effects of the pathogen-induced ROS production, we demonstrate that antioxidants that scavenge ROS, increase the sensitivity of the nematode to the infection, in stark contrast to their longevity-promoting effects under non-pathogenic conditions. In conclusion, we postulate that the generation of ROS by NADPH oxidases in the barrier epithelium is an ancient, highly conserved innate immune defense mechanism.^

Report on the practice based culminating experience as teaching assistant for "Pathology and Public Health" class taught at University of Texas School of Public Health, Houston

Objectives. The objectives of this report were to describe current best standards in online education, class competencies, class objectives, class activities and to compare the class competencies, objectives and activities undertaken with the current best practices in online teaching and to provide a list of recommendations based on the most efficacious practices. ^ Methods. Utilizing the key words- online teaching, national standards, quality, online courses, I: (1) conducted a search on Google to find the best standard for quality online courses; the search yielded National Standards for Quality Online Teaching as the gold standard in online course quality; (2) specified class objectives and competencies as well as major activities undertaken as a part of the class. Utilizing the Southern Regional Education Board evaluation checklist for online courses, I: (1) performed an analysis comparing the class activities, objectives, and competencies with the current best standards; (2) utilized the information obtained from the analysis and class experiences to develop recommendations for the most efficacious online teaching practices. ^ Results. The class met the criteria set by the Southern Regional Education Board for evaluating online classes completely in 75%, partially in 16% and did not meet the criteria in 9% cases. The majority of the parameters in which the class did not meet the standards (4 of 5) were due to technological reasons beyond the scope of the class instructor, teaching assistant and instructional design. ^ Discussion. Successful online teaching requires awareness of technology, good communication, methods, collaboration, reflection and flexibility. Creation of an online community, engaging online learners and utilizing different learning styles and assessment methods promote learning. My report proposes that online teaching should actively engage the students and teachers with multiple interactive strategies as evidenced from current best standards of online education and my “hands-on” work experience. ^ Conclusion. The report and the ideas presented are intended to create a foundation for efficacious practice on the online teaching platform. By following many of the efficacious online practices described in the report and adding from their own experiences, online instructors and teaching assistants can contribute to effective online learning. ^

Novel Use of Dual Anti-Inflammatory Therapy to Overcome Drug Resistance and Improve Functional Recovery Following Spinal Cord Injury

Over 1.2 million Americans are currently living with a traumatic spinal cord injury (SCI). Despite the need for effective therapies, there are currently no proven effective treatments that can improve recovery of function in SCI patients. Many therapeutic compounds have shown promise in preclinical models of SCI, but all of these have fallen short in clinical trials. P-glycoprotein (Pgp) is an active transporter expressed on capillary endothelial cell membranes at the blood-spinal cord barrier (BSCB). Pgp limits passive diffusion of blood-borne drugs into the CNS, by actively extruding drugs from the endothelial cell membrane. Pgp can become pathologically up-regulated, thus greatly impeding therapeutic drug delivery (‘multidrug resistance’). Importantly, many drugs that have been evaluated for the treatment of SCI are Pgp substrates. We hypothesized that Pgp-mediated drug resistance diminishes the delivery and efficacy of neuroprotective drugs following SCI. We observed a progressive, spatial spread of Pgp overexpression within the injured spinal cord. To assess Pgp function, we examined spinal cord uptake of systemically-delivered riluzole, a drug that is currently being evaluated in clinical trials as an SCI intervention. Blood-to-spinal cord riluzole penetration was reduced following SCI in wild-type but not Pgp-null rats, highlighting a critical role for Pgp in mediating spinal cord drug resistance after injury. Others have shown that pro-inflammatory signaling drives Pgp up-regulation in cancer and epilepsy. We have detected inflammation in both acutely- and chronically-injured spinal cord tissue. We therefore evaluated the ability of the dual COX-/5-LOX inhibitor licofelone to attenuate Pgp-mediated drug resistance following SCI. Licofelone treatment both reduced spinal cord Pgp levels and enhanced spinal cord riluzole bioavailability following SCI. Thus, we propose that licofelone may offer a new combinatorial treatment strategy to enhance spinal cord drug delivery following SCI. Additionally, we assessed the ability of licofelone, riluzole, or both to enhance recovery of locomotor function following SCI. We found that licofelone treatment conferred a significant improvement in hindlimb function that was sustained through the end of the study. In contrast, riluzole did not improve functional outcome. We therefore conclude that licofelone holds promise as a potential neuroprotective intervention for SCI.