Cost-Effectiveness of Different Diagnostic Strategies in Suspected Stable Coronary Artery Disease in Portugal

BACKGROUND: Cost-effectiveness is an increasingly important factor in the choice of a test or therapy. OBJECTIVE: To assess the cost-effectiveness of various methods routinely used for the diagnosis of stable coronary disease in Portugal. METHODS: Seven diagnostic strategies were assessed. The cost-effectiveness of each strategy was defined as the cost per correct diagnosis (inclusion or exclusion of obstructive coronary artery disease) in a symptomatic patient. The cost and effectiveness of each method were assessed using Bayesian inference and decision-making tree analyses, with the pretest likelihood of disease ranging from 10% to 90%. RESULTS: The cost-effectiveness of diagnostic strategies was strongly dependent on the pretest likelihood of disease. In patients with a pretest likelihood of disease of ≤50%, the diagnostic algorithms, which include cardiac computed tomography angiography, were the most cost-effective. In these patients, depending on the pretest likelihood of disease and the willingness to pay for an additional correct diagnosis, computed tomography angiography may be used as a frontline test or reserved for patients with positive/inconclusive ergometric test results or a calcium score of >0. In patients with a pretest likelihood of disease of ≥ 60%, up-front invasive coronary angiography appears to be the most cost-effective strategy. CONCLUSIONS: Diagnostic algorithms that include cardiac computed tomography angiography are the most cost-effective in symptomatic patients with suspected stable coronary artery disease and a pretest likelihood of disease of ≤50%. In high-risk patients (pretest likelihood of disease ≥ 60%), up-front invasive coronary angiography appears to be the most cost-effective strategy. In all pretest likelihoods of disease, strategies based on ischemia appear to be more expensive and less effective compared with those based on anatomical tests.info:eu-repo/semantics/publishedVersio

ICP versus Laser Doppler Cerebrovascular Reactivity Indices to Assess Brain Autoregulatory Capacity

Objective: To explore the relationship between various autoregulatory indices in order to determine which approximate small-vessel/microvascular autoregulatory capacity most accurately. Methods: Utilizing a retrospective cohort of traumatic brain injury (TBI) patients (N=41) with: transcranial Doppler (TCD), intracranial pressure (ICP) and cortical laser Doppler flowmetry (LDF), we calculated various continuous indices of autoregulation and cerebrovascular responsiveness: A. ICP derived (pressure reactivity index (PRx) – correlation between ICP and mean arterial pressure (MAP), PAx – correlation between pulse amplitude of ICP (AMP) and MAP, RAC – correlation between AMP and cerebral perfusion pressure (CPP)), B. TCD derived (Mx – correlation between mean flow velocity (FVm) and CPP, Mx_a – correlation betrween FVm and MAP, Sx – correlation between systolic flow velocity (FVs) and CPP, Sx_a – correlation between FVs and MAP, Dx – correlation between diastolic flow index (FVd) and CPP, Dx_a – correlation between FVd and MAP), and LDF derived (Lx – correlation between LDF cerebral blood flow (CBF) and CPP, Lx_a – correlation between LDF-CBF and MAP). We assessed the relationship between these indices via Pearson correlation, Friedman test, principal component analysis (PCA), agglomerative hierarchal clustering (AHC) and k-means cluster analysis (KMCA). Results: LDF based autoregulatory index (Lx) was most associated with TCD based Mx/Mx_a and Dx/Dx_a across Pearson correlation, PCA, AHC and KMCA. Lx was only remotely associated with ICP based indices (PRx, PAx, RAC). TCD based Sx/Sx_a were more closely associated with ICP derived PRx, PAx and RAC. This indicates that vascular derived indices of autoregulatory capacity (ie. TCD and LDF based) co-vary, with Sx/Sx_a being the exception. Whereas, indices of cerebrovascular reactivity derived from pulsatile CBV (ie. ICP indices) appear to not be closely related to those of vascular origin. Conclusions: Transcranial Doppler Mx is the most closely associated with LDF based Lx/Lx_a. Both Sx/Sx-a and the ICP derived indices appear to be dissociated with LDF based cerebrovascular reactivity, leaving Mx/Mx-a as a better surrogate for the assessment of cortical small vessel/microvascular cerebrovascular reactivity. Sx/Sx_a co-cluster/co-vary with ICP derived indices, as seen in our previous work.This work was made possible through salary support through the Cambridge Commonwealth Trust Scholarship, the Royal College of Surgeons of Canada – Harry S. Morton Travelling Fellowship in Surgery, the University of Manitoba Clinician Investigator Program, R. Samuel McLaughlin Research and Education Award, the Manitoba Medical Service Foundation, and the University of Manitoba Faculty of Medicine Dean’s Fellowship Fund. These studies were supported by National Institute for Healthcare Research (NIHR, UK) through the Acute Brain Injury and Repair theme of the Cambridge NIHR Biomedical Research Centre, an NIHR Senior Investigator Award to DKM. Authors were also supported by a European Union Framework Program 7 grant (CENTER-TBI; Grant Agreement No. 602150) MC is supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI17C1790). JD is supported by a Woolf Fisher Scholarship (NZ)

Transcranial Doppler Monitoring of Intracranial Pressure Plateau Waves

$\textbf{BACKGROUND}$: Transcranial Doppler (TCD) has been used to estimate ICP noninvasively (nICP); however, its accuracy varies depending on different types of intracranial hypertension. Given the high specificity of TCD to detect cerebrovascular events, this study aimed to compare four TCD-based nICP methods during plateau waves of ICP. $\textbf{METHODS}$: A total of 36 plateau waves were identified in 27 patients (traumatic brain injury) with TCD, ICP, and ABP simultaneous recordings. The nICP methods were based on: (1) interaction between flow velocity (FV) and ABP using a "black-box" mathematical model (\textit{nICP_BB}); (2) diastolic FV (\textit{nICP_FV}$_{d}$); (3) critical closing pressure (\textit{nICP_CrCP}), and (4) pulsatility index (\textit{nICP_PI}). Analyses focused on relative changes in time domain between ICP and noninvasive estimators during plateau waves and the magnitude of changes ($\textit{∆}$ between baseline and plateau) in real ICP and its estimators. A ROC analysis for an ICP threshold of 35 mmHg was performed. $\textbf{RESULTS}$: In time domain, \textit{nICP_PI, nICP_BB,} and \textit{nICP_CrCP} presented similar correlations: 0.80 ± 0.24, 0.78 ± 0.15, and 0.78 ± 0.30, respectively. \textit{nICP_FV}$_{d}$ presented a weaker correlation (R = 0.62 ± 0.46). Correlations between ∆ICP and ∆nICP were better represented by \textit{nICP_CrCP} and BB, R = 0.48, 0.44 (p < 0.05), respectively. \textit{nICP_FV}$_{d}$ and $\textit{PI}$ presented nonsignificant $\textit{∆}$ correlations. ROC analysis showed moderate to good areas under the curve for all methods: \textit{nICP_BB}, 0.82; \textit{nICP_FV}$_{d}$, 0.77; \textit{nICP_CrCP}, 0.79; and \textit{nICP_PI}, 0.81. $\textbf{CONCLUSIONS}$: Changes of ICP in time domain during plateau waves were replicated by nICP methods with strong correlations. In addition, the methods presented high performance for detection of intracranial hypertension. However, absolute accuracy for noninvasive ICP assessment using TCD is still low and requires further improvement

Non-invasive Monitoring of Intracranial Pressure Using Transcranial Doppler Ultrasonography: Is It Possible?

Although intracranial pressure (ICP) is essential to guide management of patients suffering from acute brain diseases, this signal is often neglected outside the neurocritical care environment. This is mainly attributed to the intrinsic risks of the available invasive techniques, which have prevented ICP monitoring in many conditions affecting the intracranial homeostasis, from mild traumatic brain injury to liver encephalopathy. In such scenario, methods for non-invasive monitoring of ICP (nICP) could improve clinical management of these conditions. A review of the literature was performed on PUBMED using the search keywords 'Transcranial Doppler non-invasive intracranial pressure.' Transcranial Doppler (TCD) is a technique primarily aimed at assessing the cerebrovascular dynamics through the cerebral blood flow velocity (FV). Its applicability for nICP assessment emerged from observation that some TCD-derived parameters change during increase of ICP, such as the shape of FV pulse waveform or pulsatility index. Methods were grouped as: based on TCD pulsatility index; aimed at non-invasive estimation of cerebral perfusion pressure and model-based methods. Published studies present with different accuracies, with prediction abilities (AUCs) for detection of ICP ≥20 mmHg ranging from 0.62 to 0.92. This discrepancy could result from inconsistent assessment measures and application in different conditions, from traumatic brain injury to hydrocephalus and stroke. Most of the reports stress a potential advantage of TCD as it provides the possibility to monitor changes of ICP in time. Overall accuracy for TCD-based methods ranges around ±12 mmHg, with a great potential of tracing dynamical changes of ICP in time, particularly those of vasogenic nature.Cambridge Commonwealth, European & International Trust Scholarship (University of Cambridge) provided financial support in the form of Scholarship funding for DC. Woolf Fisher Trust provided financial support in the form of Scholarship funding for JD. Gates Cambridge Trust provided financial support in the form of Scholarship funding for XL. CNPQ provided financial support in the form of Scholarship funding for BCTC (Research Project 203792/2014-9). NIHR Brain Injury Healthcare Technology Co-operative, Cambridge, UK provided financial support in the form of equipment funding for DC, BC and MC. The sponsors had no role in the design or conduct of this manuscript.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s12028-016-0258-

Looking into the abyss? Brazil at the mid-2010s

The Brazilian economy in 2015 was afflicted by a lethal combination of decelerating activity and accelerating inflation. Expectations for 2016 are equally or even more adverse, since the effects of rising unemployment emerge only after a lag. The domestic debate has pitted analysts who believe the crisis is due exclusively to past policy mistakes against those who believe that all was well until the government decided to implement austerity policies in 2015. A closer examination of the evidence shows that, in fact, both causes contributed to the crisis. But it also suggests that its depth has a more proximate cause in the political collapse of the federal government in 2015, which led Brazilian society to an impasse for which one cannot yet visualize the solution

Assessment of non-invasive ICP during CSF infusion test: an approach with transcranial Doppler.

BACKGROUND: This study aimed to compare four non-invasive intracranial pressure (nICP) methods in a prospective cohort of hydrocephalus patients whose cerebrospinal fluid dynamics was investigated using infusion tests involving controllable test-rise of ICP. METHOD: Cerebral blood flow velocity (FV), ICP and non-invasive arterial blood pressure (ABP) were recorded in 53 patients diagnosed for hydrocephalus. Non-invasive ICP methods were based on: (1) interaction between FV and ABP using black-box model (nICP_BB); (2) diastolic FV (nICP_FVd); (3) critical closing pressure (nICP_CrCP); (4) transcranial Doppler-derived pulsatility index (nICP_PI). Correlation between rise in ICP (∆ICP) and ∆nICP and averaged correlations for changes in time between ICP and nICP during infusion test were investigated. RESULTS: From baseline to plateau, all nICP estimators increased significantly. Correlations between ∆ICP and ∆nICP were better represented by nICP_PI and nICP_BB: 0.45 and 0.30 (p < 0.05). nICP_FVd and nICP_CrCP presented non-significant correlations: -0.17 (p = 0.21), 0.21 (p = 0.13). For changes in ICP during individual infusion test nICP_PI, nICP_BB and nICP_FVd presented similar correlations with ICP: 0.39 ± 0.40, 0.39 ± 0.43 and 0.35 ± 0.41 respectively. However, nICP_CrCP presented a weaker correlation (R = 0.29 ± 0.24). CONCLUSIONS: Out of the four methods, nICP_PI was the one with best performance for predicting changes in ∆ICP during infusion test, followed by nICP_BB. Unreliable correlations were shown by nICP_FVd and nICP_CrCP. Changes of ICP observed during the test were expressed by nICP values with only moderate correlations.DC is supported by a Cambridge Commonwealth, European & International Trust Scholarship, University of Cambridge. JD is supported by a Woolf Fisher Trust Scholarship. XL is supported by a Gates Cambridge Trust Scholarship. BCTC is supported by CNPQ (Research Project 203792/2014-9). DC and MC are partially supported by NIHR Brain Injury Healthcare Technology Co-operative, Cambridge, UK.This is the final version of the article. It was first available from Springer via http://dx.doi.org/10.1007/s00701-015-2661-

The Portuguese Registry of Hypertrophic Cardiomyopathy: Overall results

INTRODUCTION: We report the results of the Portuguese Registry of Hypertrophic Cardiomyopathy, an initiative that reflects the current spectrum of cardiology centers throughout the territory of Portugal. METHODS: A direct invitation to participate was sent to cardiology departments. Baseline and outcome data were collected. RESULTS: A total of 29 centers participated and 1042 patients were recruited. Four centers recruited 49% of the patients, of whom 59% were male, and mean age at diagnosis was 53±16 years. Hypertrophic cardiomyopathy (HCM) was identified as familial in 33%. The major reason for diagnosis was symptoms (53%). HCM was obstructive in 35% of cases and genetic testing was performed in 51%. Invasive septal reduction therapy was offered to 8% (23% of obstructive patients). Most patients (84%) had an estimated five-year risk of sudden death of <6%. Thirteen percent received an implantable cardioverter-defibrillator. After a median follow-up of 3.3 years (interquartile range [P25-P75] 1.3-6.5 years), 31% were asymptomatic. All-cause mortality was 1.19%/year and cardiovascular mortality 0.65%/year. The incidence of heart failure-related death was 0.25%/year, of sudden cardiac death 0.22%/year and of stroke-related death 0.04%/year. Heart failure-related death plus heart transplantation occurred in 0.27%/year and sudden cardiac death plus equivalents occurred in 0.53%/year. CONCLUSIONS: Contemporary HCM in Portugal is characterized by relatively advanced age at diagnosis, and a high proportion of invasive treatment of obstructive forms. Long-term mortality is low; heart failure is the most common cause of death followed by sudden cardiac death. However, the burden of morbidity remains considerable, emphasizing the need for disease-specific treatments that impact the natural history of the disease

On Switched Control Design of Linear Time-Invariant Systems with Polytopic Uncertainties

This paper proposes a new switched control design method for some classes of linear time-invariant systems with polytopic uncertainties. This method uses a quadratic Lyapunov function to design the feedback controller gains based on linear matrix inequalities (LMIs). The controller gain is chosen by a switching law that returns the smallest value of the time derivative of the Lyapunov function. The proposed methodology offers less conservative alternative than the well-known controller for uncertain systems with only one state feedback gain. The control design of a magnetic levitator illustrates the procedure

Ultrastructural changes in the Haemonchus contortus cuticle exposed to Acacia mearnsii extract.

Haemonchus contortus é um dos parasitos mais patogênicos para pequenos ruminantes em regiões tropicais e subtropicais em todo o mundo, inclusive no Brasil. O objetivo do trabalho foi analisar alterações ultraestruturais na cutícula de H. contortus após contato com extrato de Acacia mearnsii

Excess Capital and Liquidity Management

These notes present a new approach to corporate finance, one in which financing is not determined by prospective income streams but by financing opportunities, liquidity considerations, and prospective capital gains. This approach substantially modifies the traditional view of high interest rates as a discouragement to speculation; the Keynesian and Post-Keynesian theory of liquidity preference as the opportunity cost of investment; and the notion of the liquidity premium as a factor in determining the rate of interest on longer-term maturities