Anticoagulated patient’s perception of their illness, their beliefs about the anticoagulant therapy prescribed and the relationship with adherence: impact of novel oral anticoagulant therapy – study protocol for The Switching Study: a prospective cohort study

Background Anticoagulant therapy is prescribed for millions of patients worldwide for the prevention and treatment of both arterial and venous thrombosis. Historically, only vitamin K antagonists have been available for clinicians to prescribe. The anticoagulation landscape is changing. The recent availability of the novel oral anticoagulants overcome many of the disadvantages associated with vitamin K antagonists. However the lack of formal monitoring and clinic follow-up is a concern for clinicians, as medication adherence is being assumed, which is known to decline in patients prescribed medications for chronic conditions. The switching study is a programme of work investigating the association between medication adherence and patient’s beliefs about anticoagulation therapy (warfarin and subsequently novel oral anticoagulants), together with beliefs about their illness and anticoagulation related quality of life.Methods/designThe anticoagulation database at King’s College Hospital will be interrogated and two groups of patients will be identified; those with a time in therapeutic range on warfarin of ≥75 % and those <50 %. These groups of patients will have their illness perceptions, anticoagulation specific quality of life and beliefs about medications compared. Those patients in the time in therapeutic range <50 % group, will be then be invited to switch to a novel oral anticoagulant, as per local guidance. Those patients, who do switch, will then be followed longitudinally and have their adherence, illness perceptions, anticoagulation specific quality of life and beliefs about medications, re-evaluated on the novel agent. The results from these sub-studies, will inform a clinical pathway to support patients on these novel agents, which will be evaluated in an independent group of patients.DiscussionThe results from the switching study will be used to develop a clinical pathway to support patient’s prescribed novel oral anticoagulant therapy long-term

Review on Synchronization for OFDM Systems

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation scheme. It is widely used modulation technique because it has high data rate, high spectral efficiency and robustness to multipath fading channel. One of the major drawbacks of OFDM system is synchronization. It is very sensitive to frequency synchronization errors in the form of Carrier Frequency Offset (CFO). The Carrier Frequency Offset can causes Inter Carrier Interference (ICI) and destroy the orthogonality of the OFDM system. Therefore it is necessary to perform frequency synchronization. In this paper various Carrier Frequency Offset Estimation methods are presented

Women's views, adherence and experience with postnatal thromboprophylaxis

Introduction Based on current guidelines, many women qualify for postnatal thromboprophylaxis following childbirth, however, little information exists on how adherent women are and their experiences to both pharmacological and mechanical forms of thromboprophylaxis. Materials and methods Women requiring postnatal thromboprophylaxis were given questionnaire packs exploring their beliefs about enoxaparin, anti-embolic stockings (AES) and intermittent pneumatic compression devices (IPCD). Women were also asked to complete a diary recording when doses of enoxaparin were injected, along with an estimation of the number of hours the AES were worn each day, if at all. Results were entered onto SPSS and analysed. Results Sixty-seven women completed the questionnaire packs. Adherence to enoxaparin therapy was relatively high (82.4%). Women self-reported sub-optimal adherence levels to the AES, with 24% stating they never wore them once home. Reasons for this included being mobile, feeling hot and feeling as if they were cutting circulation off in the legs. Women reported a high level of acceptance of IPCD post caesarean section and would be happy for IPCD to be applied again in future deliveries, if required. Conclusions Although many women are adherent to postnatal TP, our findings suggest that adherence to AES is sub-optimal following discharge from hospital and therefore their usefulness is questionable. Front-line clinical staff should discuss the importance of adherence to postnatal TP, in order to avert preventable venous thromboembolic events

Wave functions and annihilation widths of heavy quarkonia

Within the framework of nonrelativistic quark-antiquark Cornell potential model formalism, we study the annihilation of heavy quarkonia. We determine their annihilation widths resulting into $\gamma\gamma$, $gg$, $3\gamma$, $3g$ and $\gamma gg$ and compare our findings with the available theoretical results and experimental data. We also provide the charge radii and absolute square of radial Schr\"odinger wave function at zero quark-antiquark separation.Comment: 2 figures, 6 table

ON PILOT CONTAMINATION IN MASSIVE MULTIPLE-INPUT MULTIPLE OUTPUT SYSTEM WITH LEAST SQUARE METHOD AND ZERO FORCING RECEIVER

Massive Multiple-Input Multiple-Output (MIMO) wireless communications refers to use of large number of antennas at transmitter and receiver to enhance spectral and energy efficiency. However, its performance is limited by a problem known as pilot contamination. In this paper, we present a comprehensive overview of massive MIMO system and studied degradation in performance due to pilot contamination. To showcase such effects, we have implemented the channel estimation using Least Square (LS) method with random pilots and time shifted pilot scheme through simulations. In this study we have used zero forcing (ZF) receivers. We have also studied performance improvement in presence of pilot using MMSE receiver. Further improvement is achieved in this work by introducing precoding technique for massive MIMO systems

What are the difficulties in conducting randomised controlled trials of thromboprophylaxis in myeloma patients and how can we address these? Lessons from apixaban versus LMWH or aspirin as thromboprophylaxis in newly diagnosed multiple myeloma (TiMM) feasibility clinical trial

Routine thromboprophylaxis (TP) in newly-diagnosed multiple myeloma (NDMM) patients comprises either aspirin for standard risk patients or low molecular weight heparin for high risk patients. Studies using DOACs in cancer patients include few with myeloma. The aim of this feasibility clinical trial was to establish the foundations for creating a multicentre trial and identify any safety concerns with apixaban. Patient perspectives were sought. NDMM patients were stratified according to VTE risk and randomised to either standard TP or apixaban 2.5 mg BD and reviewed every 3 weeks throughout their chemotherapy. Two focus groups were carried out on 2 occasions at King’s College Hospital and Guy’s Hospital, London. Each lasted an hour, were recorded, transcribed and themes explored using NVivo 11. Ten patients were recruited, 2 considered high risk and received apixaban and 8 standard risk; 4 randomised to aspirin and 4 to apixaban. Five patients and 2 carers participated in the focus groups. There were no major bleeding or VTE events. Patients were not aware of the thrombotic risk associated with cancer. There is a lack of both written and verbal information on this topic. Myeloma patients were happy to be included in more than one trial simultaneously. Our study provides information on the difficulties facing physicians and patients on obtaining evidence of the safety of DOACs in the context of myeloma. Despite patients being happy to co-recruit into thromboprophylaxis trials along with chemotherapy trials this is not current practice

Fixed dose rivaroxaban can be used in extremes of bodyweight: a population pharmacokinetic analysis

Background: Emerging safety and efficacy data for rivaroxaban suggest traditional therapy and rivaroxaban are comparable in the morbidly obese. However, real-world data that indicate pharmacokinetic (PK) parameters are comparable at the extremes of body size are lacking. The International Society of Thrombosis and Haemostasis Scientific and Standardisation Committee (ISTH SSC) suggests avoiding the use of direct oral anticoagulants (DOACs) in patients weighing &gt;120 kg or with a body mass index &gt;40 kg/m 2 and gives no recommendation on the use of DOACs in those &lt;50 kg. Objectives: To generate a population PK model to understand the influence of bodyweight on rivaroxaban exposure from clinical practice data. Method: Rivaroxaban plasma concentrations and patient characteristics were collated between 2013 and 2018 at King's College Hospital anticoagulation clinic. A population PK model was developed using a nonlinear mixed effects approach and then used to simulate rivaroxaban concentrations at the extremes of bodyweight. Results: A robust population PK model derived from 913 patients weighing between 39 kg and 172 kg was developed. The model included data from n = 86 &gt;120 kg, n = 74 BMI &gt;40 kg/m 2, and n = 30 &lt;50 kg. A one-compartment model with between-subject variability on clearance and a proportional error model best described the data. Creatinine clearance calculated by Cockcroft-Gault, with lean bodyweight as the weight descriptor in this equation, was the most significant covariate influencing rivaroxaban exposure. Conclusions: Our work demonstrates rivaroxaban can be used at extremes of bodyweight provided renal function is satisfactory. We recommend that the ISTH SSC revises the current guidance with respect to rivaroxaban at extremes of body size. </p