Prostate cancer navigation: initial experience and association with time to care.

OBJECTIVE: To evaluate factors associated with use of patient navigation in a prostate cancer population and identify whether navigation is associated with prolonged time to care. Cancer patient navigation has been shown to improve access to cancer screening, diagnosis, and treatment, but little is known about patient navigation in prostate cancer care. METHODS: All men diagnosed with localized prostate cancer between 2009 and 2015 were abstracted from the MaineHealth multi-specialty tumor registry. Regression analyses controlling for patient-, disease-, and system-level factors evaluated characteristics associated with navigation utilization. The association between navigation utilization, barriers to care, and longer time to treatment was assessed with Cox proportional hazards regression. RESULTS: Of the patient population (n = 1587), 85% of men were navigated. Navigation use was associated with earlier year of diagnosis, treatment by a high-volume urologist, and lower risk disease (p < 0.05). Treatment delay was associated with low-risk disease (vs: intermediate OR 0.62, 95% CI 0.46-0.85 and high OR 0.16, 95% CI 0.1-0.25) and receipt of navigation services (OR 1.65, 95% CI 1.12-2.45) but not distance to care, insurance, or treatment choice. CONCLUSIONS: We observed that patients with low-risk prostate cancer were more likely to utilize navigation, but traditional barriers to care were not associated with utilization. Navigation was associated with longer time to treatment, which likely reflects clinically appropriate delays associated with greater shared decision making. Time to treatment may not be the ideal metric for evaluating navigation in prostate cancer; shared decision making, patient satisfaction, and psychosocial outcomes may be more appropriate.

Measurements and modeling of multipath interference at wavelengths below cable cut-off in a G.654 optical fiber span.

Transmission below the cable cut-off wavelength may be a concern in some systems, especially for an optical supervisory channel (OSC) operating below the signal transmission band in systems built with G.654 fiber. In this work, we constructed a cabled span of G.654-compliant fiber and measured the multipath interference (MPI) generated during propagation through the span at a range of wavelengths below the cable cut-offs of the constituent fibers. Measurements were made under a range of conditions including different splice losses and the presence or absence of higher order mode filters placed around the splices. MPI levels were found to be sufficiently low at wavelengths far below the average cable cut-off such that OSC transmission was penalty-free. We compare the experimental results to modeling predictions and find very good agreement.

Role and relevance of risk stratification models in the modern-day management of non-ST elevation acute coronary syndromes.

We summarise the international guidelines surrounding risk stratification as well as discuss new emerging data for future development of a new risk model in the management of patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS). NSTE-ACS accounts for the bulk of acute coronary syndrome presentations in the UK, but management strategies in this group of patients have remained a subject of debate for decades. Patients with NSTE-ACS represent a heterogeneous population with a wide variation in short-term and long-term clinical outcomes, which makes a uniform, standardised treatment approach ineffective and inappropriate. Studies in the modern era have provided some guidance in treating this subset of patients: the provision of early, more potent therapies has been shown to improve outcomes in patients at a particularly elevated risk of adverse outcomes. International guidelines recommend adopting an individualised treatment approach through the use of validated risk prediction models to identify such patients at high risk of adverse outcomes. The present available evidence, however, is based on dated demographics, different diagnostic thresholds and outdated therapies. In particular, the evidence has limited applicability to female patients and older people with frailty. Moreover, the current risk models do not capture key prognostic variables, leading to an inaccurate estimation of patients' baseline risk and subsequent mistreatment. Therefore, the current risk models are no longer fit for purpose and there is a need for risk prediction scores that account for different population demographics, higher sensitivity troponin assays and contemporary treatment options.

Angiographic and Procedural Characteristics in Frail Older Patients with Non-ST Elevation Acute Coronary Syndrome.

Background: Angiographic and procedural characteristics stratified by frailty status are not known in older patients with non-ST elevation acute coronary syndrome (NSTEACS). We evaluated angiographic and procedural characteristics in older adults with NSTEACS by frailty category, as well as associations of baseline and residual SYNTAX scores with long-term outcomes. Methods: In this study, 271 NSTEACS patients aged ≥75 years underwent coronary angiography. Frailty was assessed using the Fried criteria. Angiographic analysis was performed using QAngio® XA Medis in a core laboratory. Major adverse cardiovascular events (MACE) consisted of all-cause mortality, MI, stroke or transient ischaemic attack, repeat unplanned revascularisation and significant bleeding. Results: Mean (±SD) patient age was 80.5 ± 4.9 years. Compared with robust patients, patients with frailty had more severe culprit lesion calcification (OR 5.40; 95% CI [1.75-16.8]; p=0.03). In addition, patients with frailty had a smaller mean improvement in culprit lesion stenosis after percutaneous coronary intervention (50.6%; 95% CI [45.7-55.6]) than robust patients (58.6%; 95% CI [53.5-63.7]; p=0.042). There was no association between frailty phenotype and completeness of revascularisation (OR 0.83; 95% CI [0.36-1.93]; p=0.67). A high baseline SYNTAX score (≥33) was associated with adjusted (age and sex) 5-year MACE (HR 1.40; 95% CI [1.08-1.81]; p=0.01), as was a high residual SYNTAX score (≥8; adjusted HR 1.22; 95% CI [1.00-1.49]; p=0.047). Conclusion: Frail adults presenting with NSTEACS have more severe culprit lesion calcification. Frail adults were just as likely as robust patients to receive complete revascularisation. Baseline and residual SYNTAX score were associated with MACE at 5 years.

Impact of multimorbidity on long-term outcomes in older adults with non-ST elevation acute coronary syndrome in the North East of England: a multi-centre cohort study of patients undergoing invasive care.

OBJECTIVES: Older adults have a higher degree of multimorbidity, which may adversely affect longer term outcomes from non-ST elevation acute coronary syndrome (NSTE-ACS). We investigated the impact of multimorbidity on cardiovascular outcomes 5 years after invasive management of NSTE-ACS. DESIGN: Prospective cohort study. SETTING: Multicentre study conducted in the north of England. PARTICIPANTS: 298 patients aged ≥75 years with NSTE-ACS and referred for coronary angiography, with 264 (88.0%) completing 5-year follow-up. MAIN OUTCOME MEASURES: Multimorbidity was evaluated at baseline with the Charlson comorbidity index (CCI). The primary composite outcome was all-cause mortality, myocardial infarction, stroke, urgent repeat revascularisation or significant bleeding. RESULTS: Mean age was 80.9 (±6.1) years. The cohort median CCI score was 5 (IQR 4-7). The primary composite outcome occurred in 48.1% at 5 years, at which time 31.0% of the cohort had died. Compared with those with few comorbidities (CCI score 3-5), a higher CCI score (≥6) was positively associated with the primary composite outcome (adjusted HR (aHR) 1.64 (95% CI 1.14 to 2.35), p=0.008 adjusted for age and sex), driven by an increased risk of death (aHR 2.20 (1.38 to 3.49), p=0.001). For each additional CCI comorbidity, on average, there was a 20% increased risk of the primary composite endpoint at 5 years (aHR 1.20 (1.09 to 1.33), p<0.001). CONCLUSIONS: In older adults with NSTE-ACS referred for coronary angiography, the presence of multimorbidity is associated with an increased risk of long-term adverse cardiovascular events, driven by a higher risk of all-cause mortality. TRIAL REGISTRATION NUMBER: NCT01933581; ClinicalTrials.gov.

Five-year clinical outcomes in patients with frailty aged ≥75 years with non-ST elevation acute coronary syndrome undergoing invasive management.

Aim: Frailty is associated with adverse outcomes in older patients with acute coronary syndrome (ACS). The impact of frailty on long-term clinical outcomes following invasive management of non-ST elevation ACS (NSTEACS) is unknown. Methods and results: The multi-centre Improve Clinical Outcomes in high-risk patieNts with ACS 1 (ICON-1) prospective cohort study consisted of patients aged >75 years undergoing coronary angiography following NSTEACS. Patients were categorized by frailty assessed by Canadian Study of Health and Ageing Clinical Frailty Scale (CFS) and Fried criteria. The primary composite endpoint was all-cause mortality, unplanned revascularization, myocardial infarction, stroke, and bleeding. Of 263 patients, 33 (12.5%) were frail, 152 (57.8%) were pre-frail, and 78 (29.7%) were robust according to CFS. By Fried criteria, 70 patients (26.6%, mean age 82.1 years) were frail, 147 (55.9%, mean age 81.3 years) were pre-frail, and 46 (17.5%, mean age 79.9 years) were robust. The composite endpoint was more common at 5 years among patients with frailty according to CFS (frail: 22, 66.7%; pre-frail: 81, 53.3%; robust: 27, 34.6%, P = 0.003), with a similar trend when using Fried criteria (frail: 39, 55.7%; pre-frail: 72, 49.0%; robust: 16, 34.8%, P = 0.085). Frailty measured with both CFS and Fried criteria was associated with the primary endpoint [age and sex-adjusted hazard ratio (HR) compared with robust groups. CFS: 2.22, 95% confidence interval (CI) 1.23-4.02, P = 0.008; Fried: HR 1.81, 95% CI 1.00-3.27, P = 0.048]. Conclusion: In older patients who underwent angiography following NSTEACS, frailty is associated with an increased risk of the primary composite endpoint at 5 years. Registration: Clinicaltrials.gov NCT01933581.

Is the contemporary care of the older persons with acute coronary syndrome evidence-based?

Globally, ischaemic heart disease is the leading cause of death, with a higher mortality burden amongst older adults. Although advancing age is associated with a higher risk of adverse outcomes following acute coronary syndrome (ACS), older patients are less likely to receive evidence-based medications and coronary angiography. Guideline recommendations for managing ACS are often based on studies that exclude older patients, and more contemporary trials have been underpowered and produced inconsistent findings. There is also limited evidence for how frailty and comorbidity should influence management decisions. This review focuses on the current evidence base for the medical and percutaneous management of ACS in older patients and highlights the distinct need to enrol older patients with ACS into well-powered, large-scale randomized trials.

Inelastic scattering with Chebyshev polynomials and preconditioned conjugate gradient minimization.

We describe and test an implementation, using a basis set of Chebyshev polynomials, of a variational method for solving scattering problems in quantum mechanics. This minimum error method (MEM) determines the wave function Psi by minimizing the least-squares error in the function (H Psi - E Psi), where E is the desired scattering energy. We compare the MEM to an alternative, the Kohn variational principle (KVP), by solving the Secrest-Johnson model of two-dimensional inelastic scattering, which has been studied previously using the KVP and for which other numerical solutions are available. We use a conjugate gradient (CG) method to minimize the error, and by preconditioning the CG search, we are able to greatly reduce the number of iterations necessary; the method is thus faster and more stable than a matrix inversion, as is required in the KVP. Also, we avoid errors due to scattering off of the boundaries, which presents substantial problems for other methods, by matching the wave function in the interaction region to the correct asymptotic states at the specified energy; the use of Chebyshev polynomials allows this boundary condition to be implemented accurately. The use of Chebyshev polynomials allows for a rapid and accurate evaluation of the kinetic energy. This basis set is as efficient as plane waves but does not impose an artificial periodicity on the system. There are problems in surface science and molecular electronics which cannot be solved if periodicity is imposed, and the Chebyshev basis set is a good alternative in such situations.

Dynamics of H2O and Na+ in nafion membranes.

We investigate the transport properties of a model of a hydrated Na-Nafion membrane using molecular dynamics simulations. The system consists of several Nafion chains forming a pore with the water and ions inside. At low water content, the hydrophilic domain is not continuous and diffusion is very slow. The diffusion coefficient of both water and Na+ increases with increasing hydration (more strongly so for Na+). The simulations are in qualitative agreement with experimental results for similar systems. The diffusion coefficient is an average over the motion of ions or water molecules located in different environments. To better understand the role of the environment, we calculate the distribution of the residence times of the ion (or water) at different locations in the system. We discuss the transport mechanism in light of this information.

Development and evaluation of the "BRISK Scale," a brief observational measure of risk communication competence.

OBJECTIVE: To develop and evaluate a brief observational measure of clinical risk communication competence. METHODS: A 4-item checklist-type measure, the BRISK (Brief Risk Information Skill) Scale, was developed by selecting and refining items from a more comprehensive measure of clinical risk communication competence. Six volunteer raters received brief training on the measure and then used the BRISK Scale to evaluate 52 video-recorded encounters between 2nd-year medical students and standardized patients conducted as part of an Observed Structured Clinical Examination (OSCE) involving a risk communication task. Internal consistency reliability, inter-rater reliability, and criterion validity were assessed. RESULTS: Raters reported no difficulties using the BRISK Scale; scores across all raters and subjects ranged from 0 to 16 with a mean score of 6.49 (SD=3.17). The BRISK Scale showed good internal consistency reliability (α=0.64), and inter-rater reliability at the scale level (Intraclass Correlation Coefficient (ICC)=0.79 for consistency, and 0.75 for absolute agreement) and individual-item level (ICC range: 0.62-.91). Novice raters' BRISK Scale scores were highly correlated (r=0.84, p<0.01) with expert raters' scores on the Risk Communication Content measure, a more comprehensive measure of risk communication competence. CONCLUSIONS: The BRISK Scale is a promising new brief observational measure of clinical risk communication competence.

A pulsating coronary vessel phantom for two- and three-dimensional intravascular ultrasound studies.

The evaluation of new techniques for 2-D and 3-D intravascular ultrasound (US) imaging (IVUS) often requires the use of a pulsating coronary phantom. This study describes the design, construction and evaluation of a phantom simulating the pulsation of a human coronary artery for IVUS studies. Polyvinyl alcohol (PVA) cryogel was used as a tissue mimic for the coronary vessel, which was incorporated in a custom-built assembly. The phantom was programmed to pulsate under servomotor control, to model the pulsation of a normal coronary artery and 2-D IVUS images were obtained using an IVUS imaging catheter. To evaluate the performance of the phantom, the lumen area variation of the phantom was determined and compared with the programmed pulsation waveforms. Our results showed that phantom pulsation correlated well with the programmed pulsation waveform (r = 0.97). The deviation of the least squares line from the line of identity was calculated to be < 4%.

Minimum-error method for scattering problems in quantum mechanics: Two stable and efficient implementations.

We examine here, by using a simple example, two implementations of the minimum error method (MEM), a least-squares minimization for scattering problems in quantum mechanics, and show that they provide an efficient, numerically stable alternative to Kohn variational principle. MEM defines an error-functional consisting of the sum of the values of (HPsi - EPsi)2 at a set of grid points. The wave function Psi, is forced to satisfy the scattering boundary conditions and is determined by minimizing the least-squares error. We study two implementations of this idea. In one, we represent the wave function as a linear combination of Chebyshev polynomials and minimize the error by varying the coefficients of the expansion and the R-matrix (present in the asymptotic form of Psi). This leads to a linear equation for the coefficients and the R-matrix, which we solve by matrix inversion. In the other implementation, we use a conjugate-gradient procedure to minimize the error with respect to the values of Psi at the grid points and the R-matrix. The use of the Chebyshev polynomials allows an efficient and accurate calculation of the derivative of the wave function, by using Fast Chebyshev Transforms. We find that, unlike KVP, MEM is numerically stable when we use the R-matrix asymptotic condition and gives accurate wave functions in the interaction region.

Electronic states of linear Au clusters supported on metal surfaces: why are they like those of a particle in a box?

Scanning tunneling spectroscopy and microscopy show that the empty states of linear Au clusters supported on a metal surface behave as if they are the states of an electron in an empty one-dimensional box. We show here that certain difficulties of this description are removed by a particle-in-a-cylinder model. This interpretation is supported by density functional calculations.

A study of the reactions of molecular hydrogen with small gold clusters.

This work presents a study of reactions between neutral and negatively charged Au(n) clusters (n=2,3) and molecular hydrogen. The binding energies of the first and second hydrogen molecule to the gold clusters were determined using density functional theory (DFT), second order perturbation theory (MP2) and coupled cluster (CCSD(T)) methods. It is found that molecular hydrogen easily binds to neutral Au(2) and Au(3) clusters with binding energies of 0.55 eV and 0.71 eV, respectively. The barriers to H(2) dissociation on these clusters with respect to Au(n)H(2) complexes are 1.10 eV and 0.59 eV for n=2 and 3. Although negatively charged Au(n) (-) clusters do not bind molecular hydrogen, H(2) dissociation can occur with energy barriers of 0.93 eV for Au(2) (-) and 1.39 eV for Au(3) (-). The energies of the Au(2)H(2) (-) and Au(3)H(2) (-) complexes with dissociated hydrogen molecules are lower than the energies of Au(2) (-)+H(2) and Au(3) (-)+H(2) by 0.49 eV and 0.96 eV, respectively. There is satisfactory agreement between the DFT and CCSD(T) results for binding energies, but the agreement is not as good for barrier heights.