RESUMO
BACKGROUND: HIV patients face considerable acute and chronic healthcare needs and battling the HIV epidemic remains of the utmost importance. By focusing on health outcomes in relation to the cost of care, value-based healthcare (VBHC) proposes a strategy to optimize quality of care and cost-efficiency. Its implementation may provide an answer to the increasing pressure to optimize spending in healthcare while improving patient outcomes. This paper describes a pragmatic value-based healthcare framework for HIV care. METHODS: A value-based HIV healthcare framework was developed during a series of roundtable discussions bringing together 16 clinical stakeholder representatives from the Belgian HIV reference centers and 2 VBHC specialists. Each round of discussions was focused on a central question translating a concept or idea to the next level of practical implementation: 1) how can VBHC principles be translated into value-based HIV care drivers; 2) how can these value-based HIV care divers be translated into value-based care objectives and activities; and 3) how can value-based HIV care objectives and activities be translated into value-based care indicators. Value drivers were linked to concrete objectives and activities using a logical framework approach. Finally, specific, measurable, and acceptable structure, process and outcomes indicators were defined to complement the framework. RESULTS: Our framework identifies 4 core value areas where HIV care would benefit most from improvements: Prevention, improvement of the cascade of care, providing patient-centered HIV care and sustaining a state-of-the-art HIV disease management context. These 4 core value areas were translated into 12 actionable core value objectives. For each objective, example activities were proposed. Indicators are suggested for each level of the framework (outcome indicators for value areas and objectives, process indicators for suggested activities). CONCLUSIONS: This framework approach outlines how to define a patient- and public health centered value-based HIV care paradigm. It proposes how to translate core value drivers to practical objectives and activities and suggests defining indicators that can be used to track and improve the framework's implementation in practice.
Assuntos
Infecções por HIV , Saúde Pública , Atenção à Saúde , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Instalações de Saúde , Humanos , Assistência Centrada no PacienteRESUMO
OBJECTIVES: An increasing number of innovative therapies (e.g., gene- and cell-based treatments) have been developed in the past 20 years. Despite the significant clinical potential of these therapies, access delays may arise because of differing perspectives of manufacturers and payers regarding issues such as the value of the product, clinical and financial uncertainties, and sustainability.Managed entry agreements (MEAs) can enable access to treatments that would not be reimbursed by conventional methods because of such concerns. However, although MEA typologies exist, there is currently no structured process to come to agreements on MEAs, which can be difficult to decide upon and implement.To facilitate more structured MEA negotiations, we propose a conceptual "value-based negotiation framework" with corresponding application tools. METHODS: The framework was developed based on an iterative process of scientific literature review and expert input. RESULTS: The framework aims to (i) systematically identify and prioritize manufacturer and payer concerns about a new treatment, and (ii) select a mutually acceptable combination of MEA terms that can best address priority concerns, with the lowest possible implementation burden. CONCLUSIONS: The proposed framework will be tested in practice, and is a step toward supporting payers and manufacturers to engage in more structured, transparent negotiations to balance the needs of both sides, and enabling quicker, more transparent MEA negotiations and patient access to innovative products.
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Negociação , Terapias em Estudo , Humanos , IncertezaRESUMO
BACKGROUND: Antibiotic-associated diarrhea (AAD) is a common adverse effect of antibiotic (AB) treatment. This study aimed to measure the overall prevalence of AAD (including mild to moderate diarrhea) in hospitalized AB treated patients, to investigate associated risk factors and to document AAD associated diagnostic investigations, contamination control and treatment. METHODS: During 8 observation days (with time delay of 10-14 days between each observation day), all adult patients hospitalized at an internal medicine ward of 4 Belgian participating hospitals were screened for AB use. Patients receiving AB on the observation day were included in the study and screened for signs and symptoms of AAD using a period prevalence methodology. Clinical data were collected for all AB users and AAD related investigations and treatment were collected for the entire duration of AAD. Additionally, nurses noted daily the frequency of all extra care associated to the treatment of the diarrhea. RESULTS: A total of 2543 hospitalized patients were screened of which 743 were treated with AB (29.2%). Included AB users had a mean age of 68 yr (range 16-99) and 52% were male. Penicillins were mostly used (63%) and 19% received more than one AB. AAD was observed in 9.6% of AB users including 4 with confirmed Clostridium difficile infection. AAD started between 1 and 16 days after AB start (median 5) and had a duration of 2 to 41 days (median 4). AAD was significantly associated with higher age and the use of double AB and proton pump inhibitors. AAD patients had extra laboratory investigations (79%), received extra pharmacological treatment (42%) and 10 of them were isolated (14%). AAD related extra nursing time amounted to 51 minutes per day for the treatment of diarrhea. CONCLUSIONS: In this observational study, with one third of hospitalized patients receiving AB, an AAD period prevalence of 9.6% in AB users was found. AAD caused extra investigations and treatment and an estimated extra nursing care of almost one hour per day. Preventive action are highly recommended to reduce the prevalence of AAD and associated health care costs.
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Antibacterianos/efeitos adversos , Diarreia/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Diarreia/diagnóstico , Diarreia/etiologia , Feminino , Hospitais Gerais , Humanos , Masculino , Pessoa de Meia-Idade , Penicilinas/efeitos adversos , Penicilinas/uso terapêutico , Prevalência , Adulto JovemRESUMO
BACKGROUND: Transcatheter aortic valve implantation (TAVI) with the SAPIEN 3 device has recently shown significant clinical benefits, compared to surgical aortic valve replacement (SAVR), in patients at low risk for surgical mortality (PARTNER 3 trial, NCT02675114). Currently in Belgium, TAVI use is restricted to high-risk or inoperable patients with severe symptomatic aortic stenosis (sSAS). This cost-utility analysis aimed to assess whether TAVI with SAPIEN 3 could lead to potential cost-savings compared with SAVR, in the low-risk sSAS population in Belgium. METHODS: A previously published, two-stage, Markov-based cost-utility model was used. Clinical outcomes were captured using data from PARTNER 3 and the model was adapted for the Belgian context using cost data from the perspective of the Belgian National Healthcare System, indexed to 2022. A lifetime horizon was chosen. The model outputs included changes in direct healthcare costs, survival and health-related quality of life using TAVI versus SAVR. RESULTS: TAVI with SAPIEN 3 provides meaningful clinical and cost benefits over SAVR, in terms of an increase in quality-adjusted life years (QALYs) of 0.94 and cost-saving of 3 013 per patient. While initial procedure costs were higher for TAVI compared with SAVR, costs related to rehabilitation, disabling stroke, treated atrial fibrillation, and rehospitalization were lower. The cost-effectiveness of TAVI over SAVR remained robust in sensitivity analyses. CONCLUSION: TAVI with SAPIEN 3 may offer a meaningful alternative intervention to SAVR in Belgian low-risk patients with sSAS, showing both clinical benefits and cost savings associated with post-procedure patient management.
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Estenose da Valva Aórtica , Substituição da Valva Aórtica Transcateter , Humanos , Valva Aórtica/cirurgia , Estenose da Valva Aórtica/cirurgia , Bélgica/epidemiologia , Constrição Patológica , Análise de Custo-Efetividade , Qualidade de Vida , Ensaios Clínicos como AssuntoRESUMO
Acute hepatic porphyrias (AHP) are a group of four different rare to ultra-rare, severely debilitating, and sometimes fatal diseases that significantly impact patients' lives: 5-aminolevulinic acid (ALA) dehydratase deficiency porphyria (ADP), acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). Based on literature estimates, a conservative estimate of the number of AHP patients in Belgium requiring treatment, defined as patients experiencing recurrent attacks and/or chronic debilitating symptoms, is likely limited to 11-34 patients. These patients face a considerable unmet need, as there is currently no pharmaceutical treatment available that effectively prevents attacks and has an impact on other chronic symptoms of the disease.A panel consisting of the two European Porphyria Network1 (EPNet) centers in Belgium (Center for inborn errors of metabolism of UZ Leuven and the 'Centre Belge des Porphyries' of Erasme Hospital and LHUB-ULB) participated in an advisory board on 24 January 2020. Representatives of the sponsoring pharmaceutical company, Alnylam Pharmaceuticals, organized and attended the meeting. The objective of the meeting was to obtain expert input on the state-of-the-art clinical practice of AHP in Belgium. Following this meeting, this expert consensus statement was drafted, in collaboration with and coordinated by the EPNet centers in Belgium. This statement provides an overview of the state-of-the art in AHP, by means of a concise overview of AHP pathophysiology, clinical manifestations, and burden of disease, (Belgian) epidemiology, treatments, and proposed organization of care.
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Porfirias Hepáticas , Porfirias , Bélgica/epidemiologia , Humanos , Sintase do Porfobilinogênio/deficiência , Porfirias/diagnóstico , Porfirias/epidemiologia , Porfirias/terapia , Porfirias Hepáticas/diagnóstico , Porfirias Hepáticas/epidemiologia , Porfirias Hepáticas/terapiaRESUMO
BACKGROUND: The importance of tocolysis has been discussed extensively. Beta-2 adrenoceptor agonistic drugs like ritodrine have been the reference tocolytic drugs in most countries. Cardiovascular side-effects are frequent. Atosiban, a newer tocolytic drug, is a competitive antagonist of oxytocin and has fewer cardiovascular side effects. Although large studies exist, there is mainly subjective reporting of adverse reactions with a focus on blood pressure data. OBJECTIVES: Evaluation of the acute effects of therapeutic doses of ritodrine and atosiban in comparison to placebo on central and peripheral blood pressures, central-to-peripheral blood pressure amplification and the augmentation index (AIx) in healthy non-pregnant female volunteers. METHODS: A double-blind, randomized, crossover trial was carried out in 20 healthy non-pregnant female volunteers. Hemodynamic measurements were performed under standardized conditions. RESULTS: At steady state, central and peripheral pressures did not differ from placebo in the atosiban group. During ritodrine -infusion, central SBP increased by 11% versus placebo (p = 0.012) and peripheral SBP by 10% (p = 0.004). In contrast to atosiban and placebo, blood pressure amplification was absent in the ritodrine group. While the AIx did not change in the atosiban group, with ritodrine, the AIx tended to decrease. CONCLUSIONS: The present study shows the significant effects of ritodrine on the cardiovascular system. Atosiban has no significant effects and may be an appropriate alternative to tocolyticum, particularly in cardiovascularly complicated pregnancies.
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Pressão Sanguínea/efeitos dos fármacos , Sistema Cardiovascular/efeitos dos fármacos , Ocitocina/uso terapêutico , Ritodrina/administração & dosagem , Tocolíticos/administração & dosagem , Vasotocina/análogos & derivados , Adulto , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Ocitocina/antagonistas & inibidores , Tocolíticos/efeitos adversos , Vasotocina/administração & dosagem , Vasotocina/efeitos adversosRESUMO
BACKGROUND: Acute hepatic porphyria (AHP) is a rare, debilitating disease characterized by potentially life-threatening attacks often resulting in chronic symptoms that negatively impact daily functioning and quality of life. Symptoms of AHP prevent many individuals from working and achieving lifetime work averages. The aim of this study was to apply a public economic framework to evaluate AHP in Belgium, taking into consideration a broad range of costs that are relevant to government in relation to social benefit payments and lifetime taxes paid. METHODOLOGY: A public economic framework was developed exploring lifetime costs for government attributed to an individual with AHP and recurrent attacks in Belgium. Work-activity and lifetime direct taxes paid, indirect consumption taxes and requirements for public benefits were estimated based on established clinical pathways for AHP and compared to the general population (GP). The model includes AHP-related healthcare costs and non-AHP healthcare costs for the GP. RESULTS: Lifetime earnings are reduced in an individual with AHP by 347,802 per person (p.p.), translating to reduced lifetime taxes paid of 183,187 for an AHP individual compared to the GP. We estimate increased lifetime disability benefit support of 247,242 for an AHP individual compared to GP. Lifetime healthcare costs for a person with AHP were estimated to be 3,030,316 due to frequent hospitalisations associated with porphyria attacks compared to the GP. The lifetime costs for a person with 12 attacks per annum factoring in transfers, taxes and healthcare costs are estimated to be 3,460,745 p.p. Eliminating AHP attacks after 10 years of active disease, thus, enabling a person to return to work increases lifetime earnings by 224,575 p.p. Increased work activity in such individuals would generate an estimated 118,284 p.p. over their lifetime. The elimination of AHP attacks could also lead to reductions in disability payments of 179,184 p.p. and healthcare cost savings of 1,511,027 p.p. CONCLUSIONS: Due to severe disability resulting from constant attacks, AHP patients with recurrent attacks incur significant public costs. Lifetime taxes paid are reduced as these attacks occur during peak earning and working years. In those patients, reducing AHP attacks can confer significant fiscal benefits for government, including reduced healthcare costs, reduced disability payments and improved tax revenue.
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Porfirias Hepáticas , Qualidade de Vida , Bélgica , Custos de Cuidados de Saúde , Humanos , ImpostosRESUMO
BACKGROUND: The relationship between aortic (carotid-femoral) pulse wave velocity and stiffness measures based on local diameter and pressure readings is not yet fully understood. METHODS: We compared the relationship with age and gender of aortic pulse wave velocity to stiffness indices (compliance and distensibility coefficient) evaluated at the common carotid and femoral arteries in 2195 (1131 women) apparently healthy subjects, aged 35-55 years participating in the Asklepios study. Aortic pulse wave velocity was further compared with previously reported central arterial stiffness parameters on the same population. Subjects were divided into four age groups for analysis. RESULTS: Femoral arterial stiffness was higher in men than in women (P < 0.001) but did not change with age and no age-gender interaction was evident. Carotid arterial stiffness increased with age (P < 0.001) and showed a significant (P < 0.001) age-gender interaction, with carotid stiffness increasing more rapidly in women than in men, crossing over around the age of 45. Aortic pulse wave velocity did not differ between men and women, but did increase with age (P < 0.001). No age-gender interaction was evident. CONCLUSION: The relation with age and gender of local and central stiffness measures is not the same over the age range 35-55 in apparently healthy men and women. Depending on the central stiffness parameter used, age-gender effects evident at the carotid artery are or are not found centrally. Though the relevance of these differences requires further evaluation in a longitudinal study with outcome data, they need to be kept in mind when designing or interpreting results from arterial stiffness evaluation studies.
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Aorta/fisiologia , Artérias Carótidas/fisiologia , Artéria Femoral/fisiologia , Adulto , Fatores Etários , Bélgica , Fenômenos Biomecânicos , Velocidade do Fluxo Sanguíneo , Complacência (Medida de Distensibilidade) , Elasticidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores SexuaisRESUMO
OBJECTIVES: We developed a pragmatic modelling approach to estimate the impact of treatment as prevention (TasP); outreach testing strategies; and pre-exposure prophylaxis (PrEP) on the epidemiology of HIV and its associated pharmaceutical expenses. METHODS: Our model estimates the incremental health (in terms of new HIV diagnoses) and budget impact of two prevention scenarios (outreach+TasP and outreach+TasP+PrEP) against a 'no additional prevention' scenario. Model parameters were estimated from reported Belgian epidemiology and literature data. The analysis was performed from a healthcare payer perspective with a 15-year-time horizon. It considers subpopulation differences, HIV infections diagnosed in Belgium having occurred prior to migration, and the effects of an ageing HIV population. RESULTS: Without additional prevention measures, the annual number of new HIV diagnoses rises to over 1350 new diagnoses in 2030 as compared to baseline, resulting in a budget expenditure of 260.5 million. Implementation of outreach+TasP and outreach+TasP+PrEP results in a decrease in the number of new HIV diagnoses to 865 and 663 per year, respectively. Respective budget impacts decrease by 20.6 million and 33.7 million. CONCLUSION: Foregoing additional investments in prevention is not an option. An approach combining TasP, outreach and PrEP is most effective in reducing the number of new HIV diagnoses and the HIV treatment budget. Our model is the first pragmatic HIV model in Belgium estimating the consequences of a combined preventive approach on the HIV epidemiology and its economic burden assuming other prevention efforts such as condom use and harm reduction strategies remain the same.
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Antirretrovirais/administração & dosagem , Antirretrovirais/economia , Infecções por HIV/economia , Infecções por HIV/prevenção & controle , Modelos Econômicos , Bélgica/epidemiologia , Feminino , Infecções por HIV/epidemiologia , Humanos , MasculinoRESUMO
BACKGROUND: Recently, an expert group advised to measure carotid-femoral (cf) pulse wave velocity (PWV) on the right side of the body, and to use a sliding caliper when tape measure distance cannot be obtained in a straight line. The present study investigates the evidence for this advice by comparing the real travelled cf path lengths (RTPLs) at both body sides and comparing the straight distance (as can be obtained with a sliding caliper) with the tape measure distance. METHODS: RTPLs were measured with MRI in 98 individuals (49 men, age 21-76 years). Path lengths from the aortic arch to the carotid (AA-CA) and femoral (AA-FA) sites were determined. RTPL was calculated as (AA-FA)â-â(AA-CA) and compared between both sides. RTPLs were compared with 80% of the direct cf distance using a tape measure and the straight cf distance obtained from MRI images. RESULTS: RTPL was slightly longer [11 mm (12), Pâ<â0.001] at the right side. The 80%-rule overestimated RTPLs with 0.5% at the right and 2.7% at the left side. Straight MRI distance tended (Pâ=â0.09) to perform slightly better than tape measure distance. CONCLUSION: The travelled cf path is slightly longer at the right than at the left body side and the straight MRI distance tends to perform better than tape measure distance. The present study supports the advice of the expert consensus group to measure cf-PWV at the right body side using a sliding caliper when tape measure distance cannot be obtained in a straight line.
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Tamanho Corporal , Artérias Carótidas/fisiologia , Artéria Femoral/fisiologia , Análise de Onda de Pulso , Adulto , Idoso , Artérias Carótidas/anatomia & histologia , Feminino , Artéria Femoral/anatomia & histologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-IdadeRESUMO
We recently introduced noninvasive methods to assess local pulse wave velocity (PWV) and wave intensity ((n)dI) in arteries based on measurements of flow velocity (U) and diameter (D). Although the methods were validated in an experimental setting, clinical application remains lacking. The aim of this study was therefore to investigate the effect of age and gender on PWV and (n)dI in the carotid and femoral arteries of an existing population. We measured D and U in the carotid and femoral arteries of 1,774 healthy subjects aged 35-55 yr, a subgroup of the Asklepios population. With the use of the lnDU-loop method, we calculated local PWV, which was used to determine arterial distensibility ((n)Ds). We then used the new algorithm to determine maximum forward and backward wave intensities ((n)dI(+max) and (n)dI(-min), respectively) and the reflection index ((n)RI). On average, PWV was higher, and (n)Ds was lower in the femoral than at the carotid arteries. At the carotid artery, PWV increased with age, but (n)Ds, (n)dI(+max), and (n)dI(-min) decreased; (n)RI did not change with age. At the femoral artery, PWV was higher, and (n)Ds was lower in male, but all parameters did not change significantly with age in both women and men. We conclude that the carotid artery is more affected by the aging process than the femoral artery, even in healthy subjects. The new techniques provide mechanical and hemodynamic parameters, requiring only D and U measurements, both of which can be acquired using ultrasound equipment widely available today, hence their advantage for potential use in the clinical setting.
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Envelhecimento/fisiologia , Artérias Carótidas/fisiologia , Artéria Femoral/fisiologia , Fluxo Pulsátil/fisiologia , Análise de Onda de Pulso/métodos , Caracteres Sexuais , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Hemodinâmica/fisiologia , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-IdadeRESUMO
INTRODUCTION: The ambulatory arterial stiffness index (AASI), derived from ambulatory blood pressure monitoring (ABPM) recordings, has been proposed as a surrogate marker of arterial stiffness. However, there is controversy to what extent it reflects stiffness or is affected by other parameters. Using a previously validated one-dimensional computer model of the arterial circulation, the relative importance of the different determinants of the AASI was explored. METHODS: Arterial distensibility (inverse of stiffness), peripheral resistance, heart rate, maximal cardiac elastance and venous filling pressure were varied from 80 to 120% of their initial value in steps of 10% to generate 3125 BP values, mimicking the daily fluctuations in one theoretical patient. From this dataset, we assessed the confidence with which AASI can be derived in this patient, as well as the influence of different individual parameters on AASI. To assess the ability of AASI to detect large changes in arterial stiffness, two additional patients were simulated with a distensibility of 50 and 25% of the default distensibility, respectively. RESULTS: The distribution of AASI values, obtained from 10â000 ABPM simulations (each using 72 BP values randomly selected among 3125) was normal [AASIâ=â0.43â±â0.04 (SD)]. An increase in heart rate, distensibility or resistance from 80 to 120% of its default value caused the AASI to decrease by 37, 21 or 9%, respectively. Whereas there was no overlap in the distensibility ranges for the three theoretical patients, the amount of overlap between the AASI distributions was substantial. CONCLUSION: The confounding effects of vascular resistance and heart rate seriously limit the use of AASI as a marker of stiffness.
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Modelos Cardiovasculares , Rigidez Vascular , Artérias/fisiologia , Humanos , Índice de Gravidade de DoençaRESUMO
OBJECTIVES: This study sought to assess the relationship between central pressure profiles and cardiovascular events (CVEs) in a large community-based sample. BACKGROUND: Experimental and physiologic data mechanistically implicate wave reflections in the pathogenesis of left ventricular failure and cardiovascular disease, but their association with these outcomes in the general population is unclear. METHODS: Aortic pressure waveforms were derived from a generalized transfer function applied to the radial pressure waveform recorded noninvasively from 5,960 participants in the Multiethnic Study of Atherosclerosis. The central pressure waveform was separated into forward and reflected waves using a physiologic flow waveform. Reflection magnitude (RM = [Reflected/Forward wave amplitude] × 100), augmentation index ([Second/First systolic peak] × 100) and pulse pressure amplification ([Radial/aortic pulse pressure] × 100) were assessed as predictors of CVEs and congestive heart failure (CHF) during a median follow-up of 7.61 years. RESULTS: After adjustment for established risk factors, aortic AIx independently predicted hard CVEs (hazard ratio [HR] per 10% increase: 1.08; 95% confidence interval [CI]: 1.01 to 1.14; p = 0.016), whereas PPA independently predicted all CVEs (HR per 10% increase: 0.82; 95% CI: 0.70 to 0.96; p = 0.012). RM was independently predictive of all CVEs (HR per 10% increase: 1.34; 95% CI: 1.08 to 1.67; p = 0.009) and hard CVEs (HR per 10% increase: 1.46; 95% CI: 1.12 to 1.90; p = 0.006) and was strongly predictive of new-onset CHF (HR per 10% increase: 2.69; 95% CI: 1.79 to 4.04; p < 0.0001), comparing favorably to other risk factors for CHF as per various measures of model performance, reclassification, and discrimination. In a fully adjusted model, compared to nonhypertensive subjects with low RM, the HRs (95% CI) for hypertensive subjects with low RM, nonhypertensive subjects with high RM, and hypertensive subjects with high RM were 1.81 (0.85 to 3.86), 2.16 (1.07 to 5.01), and 3.98 (1.96 to 8.05), respectively. CONCLUSIONS: Arterial wave reflections represent a novel strong risk factor for CHF in the general population.
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Aorta Torácica/fisiopatologia , Pressão Arterial/fisiologia , Aterosclerose/etnologia , Etnicidade , Insuficiência Cardíaca/etnologia , Idoso , Idoso de 80 Anos ou mais , Aterosclerose/complicações , Aterosclerose/fisiopatologia , Velocidade do Fluxo Sanguíneo , Determinação da Pressão Arterial , Doenças Cardiovasculares/etnologia , Doenças Cardiovasculares/fisiopatologia , Elasticidade , Seguimentos , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Incidência , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Inquéritos e Questionários , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: The current standard for arterial stiffness assessment, aortic pulse wave velocity (aPWV), is measured at diastolic pressure. Arterial stiffness, however, is pressure dependent. At the carotid artery level, the degree of this dependency can be quantified as the difference (ΔPWV) between systolic and diastolic (cPWVd) carotid pulse wave velocity. Biomechanically, a greater ΔPWV implies greater increases in left ventricular afterload with physical activity. Therefore, we hypothesized, that ΔPWV is more strongly associated with left ventricular mass index (LVMI) than aPWV and cPWVd. METHODS: In 1776 healthy individuals from the Asklepios cohort (age 35-55 years), ΔPWV was obtained from combined carotid artery ultrasound and tonometry recordings. Multiple linear regression analysis was performed to investigate the associations of ΔPWV, cPWVd and aPWV with LVMI, adjusting for age, sex, mean blood pressure (MBP), central pulse pressure, and other possible confounders. RESULTS: ΔPWV was 2.4â±â1.2âm/s (meanâ±âSD), ranging from 0.8âm/s, indicating almost constant arterial stiffness over the cardiac cycle, to 4.4âm/s, reflecting substantial pressure dependency. ΔPWV was significantly associated with LVMI (ß of 2.46âg/m per m/s, Pâ<â0.001), even after full adjustment (ß of 0.56âg/m per m/s, Pâ=â0.03). cPWVd and aPWV had clear crude associations with LVMI (Pâ<â0.001), but lost significance after adjustment (ß of -0.48 and -0.33âg/m per m/s, with Pâ=â0.11 and 0.2, respectively). CONCLUSION: The change in arterial stiffness over the cardiac cycle, rather than diastolic stiffness, is independently associated with LVMI in healthy middle-aged individuals. Therefore, the pressure dependency of arterial stiffness should be considered in cardiovascular risk assessment.
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Artérias/fisiologia , Complacência (Medida de Distensibilidade) , Ventrículos do Coração/anatomia & histologia , Tamanho do Órgão , Adulto , Estudos de Coortes , Humanos , Pessoa de Meia-Idade , Valores de ReferênciaRESUMO
Stiffness of elastic arteries like the aorta predicts cardiovascular risk. By directly reflecting arterial stiffness, having the best predictive value for cardiovascular outcome and the ease of its measurement, carotid-femoral pulse wave velocity is now considered the gold standard for arterial stiffness assessment in daily practice. Many different measurement procedures have been proposed. Therefore, standardization of its measurement is urgently needed, particularly regarding the distance measurement. This consensus document advises on the measurement procedures in general and provides arguments for the use of 80% of the direct carotid-femoral distance as the most accurate distance estimate. It also advises the use of 10âm/s as new cut-off value for carotid-femoral pulse wave velocity.
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Técnicas de Diagnóstico Cardiovascular , Rigidez Vascular , Artérias Carótidas/fisiologia , Artéria Femoral/fisiologia , Humanos , Pulso ArterialRESUMO
OBJECTIVES: Carotid-femoral pulse wave velocity (PWV) is the gold standard method for determination of arterial stiffness. PWV is assessed by dividing travelled distance by travel time. Standardization and validation of the methodology for travelled distance measurement is of crucial importance. The aim of the current investigation was to standardize and validate the methodology for travelled distance measurement. METHODS: Real travelled carotid-femoral path lengths were measured with MRI in 98 healthy men/women (50% men, age 21-76 years) and are used as reference distance. This reference distance was compared with 11 estimates of aortic path length from body surface distances commonly used in PWV measurement, nine of them based on tape measures and two based on body height. Determinants of the difference between reference distance and the best body surface distance were determined. Additionally, the influence of body contours was identified. RESULTS: The tape measure distance from carotid to femoral artery (CA-FA), multiplied by 0.8, yielded the best agreement with the reference aortic path length [difference 0.26âcm (SD 3.8), not statistically significant]. Thirty percent of the variation in difference between the reference distance and tape measure distance (CA-FAâ×â0.8) was explained by age. Adding BMI increased this number to 34%. CONCLUSION: The tape measure distance from CA-FA, multiplied by 0.8, corresponds best with the real travelled aortic path length. This distance is moderately (yet statistically significantly) influenced by age and minimally by BMI.
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Aorta/anatomia & histologia , Estatura , Superfície Corporal , Artérias Carótidas/fisiologia , Artéria Femoral/fisiologia , Imageamento por Ressonância Magnética , Fluxo Pulsátil/fisiologia , Adulto , Fatores Etários , Idoso , Aorta/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Índice de Massa Corporal , Artérias Carótidas/anatomia & histologia , Feminino , Artéria Femoral/anatomia & histologia , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Fatores de TempoRESUMO
BACKGROUND: The Omron HEM-9000AI is the first automated tonometer to provide an estimate of central SBP (cSBP), which is considered to be more predictive of cardiovascular events than brachial pressure. However, considerable differences between the cSBP estimate of Omron and that of SphygmoCor have been reported, but not explained. This study assesses the sources of differences between both cSBP estimates and provides a handle on which estimate is closest to reality. METHOD: For this purpose, aortic cSBP derived from calibrated carotid SBP was used as device- and algorithm-independent reference. Radial, brachial and carotid applanation tonometry were performed in 143 black South Africans, aged 39-91 years. Each individual was measured with an Omron HEM-9000AI and a SphygmoCor. RESULTS: When using both devices as advocated by their manufacturers, the corresponding cSBP estimates correlated strongly (r = 0.99, P < 0.001), but the Omron estimate was 18.8 (4.3) mmHg higher than the SphygmoCor estimate. Aortic SBP was in between both estimates: 11.7 (5.5) mmHg lower than cSBP-Omron and 7.1 (5.0) mmHg higher than cSBP-SphygmoCor. Alternative calibration of the radial SphygmoCor-curves with radial instead of brachial pressures yielded a cSBP that was 3.0 (4.2) mmHg lower than aortic SBP. The shape of the recorded pressure waves was similar in both devices: less than 5% of the observed cSBP difference was caused by differences in wave shape. CONCLUSION: The results from this study demonstrate that the considerable difference between the central pressure estimates of Omron HEM-9000AI and SphygmoCor is due to algorithm differences, and suggest that the overestimation by Omron HEM-9000AI is larger than the underestimation by SphygmoCor.
Assuntos
Pressão Sanguínea , Artérias Carótidas/fisiologia , Manometria/métodos , Esfigmomanômetros , Adulto , Idoso , População Negra , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
The wave speed (c) and the arrival time of reflected wave (Trw) in the common left carotid artery and common left femoral artery have been evaluated in 70 healthy subjects, aged 35-55 years with a non-invasive method.