Study of the accuracy of a radial arterial pressure waveform cardiac output measurement device after cardiac surgery.

BACKGROUND: Less invasive monitoring, such as radial arterial pulse contour analysis (ProAQT® sensor), represents an alternative when hemodynamic monitoring is necessary to guide postoperative management and invasive monitoring is not technically feasible. The aim of the study is to evaluate the accuracy of the ProAQT® sensor cardiac output measurements in comparison with Pulmonary Artery Catheter (PAC) during the postoperative course of patients who underwent cardiac surgery with cardiopulmonary bypass. CASE PRESENTATION: Prospective observational study in a Surgical Intensive Care Unit of a tertiary university hospital. Ten patients with a mean age of 73.5 years were included. The main comorbidities were hypertension, diabetes, dyslipidemia and the preoperative left ejection fraction was 43.8 ± 14.5%. Regarding the type of surgery, six patients underwent valve surgery, two underwent coronary artery bypass grafting and two underwent aortic surgery. The cardiac index measured simultaneously by the ProAQT® sensor was compared with the PAC. The parameters were evaluated at predefined time points during the early postoperative courses (6 h, 12 h, 24 h, 48 h and 72 h). The degree of agreement with the cardiac index between the PAC and the ProAQT® sensor along the time points was measured using the concordance correlation coefficient, Bland-Altman analysis, and four-quadrant plot. Sixty-three pairs of measurements were analyzed. We showed that measurements of cardiac index were slightly higher with PAC (ß Ì‚ = - 0.146, p-value = 0.094). The concordance correlation coefficient for the additive model of cardiac index was 0.64 (95% Confidence Interval: 0.36, 0.82), indicating a high concordance between both sensors. Bland-Altmann analysis showed a mean bias of 0.45 L·min-1·m-2, limits of agreement from - 1.65 to 2.3 L·min-1·m-2, and percentage of error was 82.5%. Four-quadrant plot of changes in cardiac index showed a good concordance rate (75%), which increases after applying the exclusion zone (87%). CONCLUSIONS: In patients undergoing cardiac surgery, the ProAQT® sensor may be useful to monitor cardiac index during the postoperative period, especially when more invasive monitoring is not possible.

Resting-state functional dynamic connectivity and healthy aging: A sliding-window network analysis.

BACKGROUND: Graph theory has been widely used to study structural and functional brain connectivity changes in healthy aging, and occasionally with clinical samples; in both cases, during task-related and resting-state experiments. Recent studies have focused their interest on dynamic changes during a resting-state fMRI register in order to identify differences in non-stationary patterns associated with the aging process. The objective of this study was to characterize resting-state fMRI network dynamics in order to study the healthy aging process. METHOD: 114 healthy older adults were measured in a resting-state paradigm using fMRI. A sliding-window approach to graph theory was used to measure the mean degree, average path length, clustering coefficient, and small-worldness of each subnetwork, and the impact of age and time in each graph measure was assessed. RESULTS: A combined effect of age and time was detected in mean degree, average path length, and small-worldness, where participants aged 75 to 79 showed a curvilinear trend with reduced network density and increased small-world coefficient in the middle of the register. CONCLUSION: An effect of age was observed on average path length, with younger participants showing slightly lower scores.

Resting-State Functional Connectivity Dynamics in Healthy Aging: An Approach Through Network Change Point Detection.

This study aims at assessing the impact of age on the short-term temporal dynamics of the topological properties of the undirected and weighted whole-brain functional connectivity (FC) networks. We studied the association between the participant's age and the number of significant change points detected through the Network Change Point Detection algorithm. Secondary, we defined state as the resting-state functional magnetic resonance imaging (rs-fMRI) subsequence between two significant change points, obtaining the FC network in each state and participant and characterized their network topological properties. The data comprise the rs-fMRI sequences of 114 healthy individuals combined from 3 different studies conducted at the Department of Medicine, School of Medicine and Health Sciences, University of Barcelona. Participants were healthy people in the absence of any pathology that could interfere with the scanning procedures, as well as any chronic illness that implied a short-lived situation. Topological properties of everyone's FC networks were characterized by their network strength, transitivity, characteristic path length, and small-worldness, analyzing the effect of age in those observed distributions. To that effect, we constructed a mixed linear model for each network topological property with age, state, and state duration as the linear predictors. Several statistically significant relationships have been estimated between the indicators of the FC networks that show a certain regular pattern of change in the networks during the time of registration at the resting fMRI paradigm. These dynamic changes seem to be related to the age of each group studied. Healthy aging could be characterized by FC dynamics patterns.

Network change point detection in resting-state functional connectivity dynamics of mild cognitive impairment patients.

Background/Objective: This study aims to characterize the differences on the short-term temporal network dynamics of the undirected and weighted whole-brain functional connectivity between healthy aging individuals and people with mild cognitive impairment (MCI). The Network Change Point Detection algorithm was applied to identify the significant change points in the resting-state fMRI register, and we analyzed the fluctuations in the topological properties of the sub-networks between significant change points. Method: Ten MCI patients matched by gender and age in 1:1 ratio to healthy controls screened during patient recruitment. A neuropsychological evaluation was done to both groups as well as functional magnetic images were obtained with a Philips 3.0T. All the images were preprocessed and statistically analyzed through dynamic point estimation tools. Results: No statistically significant differences were found between groups in the number of significant change points in the functional connectivity networks. However, an interaction effect of age and state was detected on the intra-participant variability of the network strength. Conclusions: The progression of states was associated to higher variability in the patient's group. Additionally, higher performance in the prospective and retrospective memory scale was associated with higher median network strength.

Antecedentes/Objetivo: Este estudio tiene como objetivo caracterizar las diferencias en la red dinámica de conectividad funcional no dirigida entre un grupo de personas sanas y otro con deterioro cognitivo leve. Se aplicó un algoritmo de detección de puntos de cambio en redes complejas para identificarlos en registros fMRI en estado de reposo y se analizaron las fluctuaciones en las propiedades topológicas de las subredes entre puntos de cambio significativos. Método: Diez pacientes emparejados por sexo y edad en proporción 1:1 a controles sanos. Se realizó una evaluación neuropsicológica a ambos grupos y se obtuvieron imágenes funcionales con un Philips Ingenia 3.0T. Todas las imágenes fueron preprocesadas y analizadas estadísticamente a través de herramientas de estimación dinámica de puntos. Resultados: No se encontraron diferencias estadísticamente significativas entre ambos grupos en el número de puntos de cambio en las redes de conectividad funcional. Se detectó un efecto de interacción entre edad y la variabilidad intra-sujeto en algunos indicadores de complejidad (strength) de la red dinámica. Conclusiones: La progresión de la conectividad se asoció a una mayor variabilidad en el grupo de pacientes. Además, se puede asociar un mayor rendimiento en la escala de memoria prospectiva y retrospectiva con un mayor valor de la mediana de strength de la red.

Thyroid dysfunction induced by nivolumab: searching for disease patterns and outcomes.

PURPOSE: Nivolumab is a monoclonal antibody that blocks the activation of programmed death-1 receptor, promoting T-cell activation against cancer cells. Thyroid dysfunction (TD) is a common immune-related adverse event (irAE) induced by nivolumab. We report the prevalence, patterns and outcomes of nivolumab-induced TD among cancer patients in our center. METHODS: All patients treated with nivolumab during 2016 were included. We assessed thyroid function tests, thyroid autoimmunity, thyroid imaging, and clinical outcome during nivolumab therapy as well as overall survival (OS). RESULTS: Seventy-three patients (55 with non-small-cell lung cancer [NSCLC], 9 with melanoma and 9 with Hodgkin lymphoma) were included. Median of follow up: 390.5 days. Seventeen patients (23.3%) developed TD during treatment. Thyrotoxicosis was reported in seven patients. Serum thyroid-stimulating hormone (TSH) nadir occurred after a median of 51 days (95% CI: 35-71). Thyroid antibodies were positive in three of the seven patients. Five of the seven hyperthyroid patients became hypothyroid later, and four of them required levothyroxine treatment. Primary hypothyroidism occurred in ten patients. Serum TSH peak occurred after a median of 110 days [95% CI: 85.2-197]. Thyroid autoimmunity was positive in one patient. In patients with NSCLC, TD was associated with better OS (HR = 0.4 [95% CI: 0.17-0.94]; p = 0.035). CONCLUSIONS: TD induced by nivolumab is a common and heterogeneous irAE. Thyrotoxicosis develops earlier than hypothyroidism. A pattern consistent with a transient thyroiditis followed by hypothyroidism was observed in one-third of patients. Our results suggest that patients with NSCLC and nivolumab-induced TD might have better survival.

Age-related changes in resting-state functional connectivity in older adults.

Age-related changes in the brain connectivity of healthy older adults have been widely studied in recent years, with some differences in the obtained results. Most of these studies showed decreases in general functional connectivity, but they also found increases in some particular regions and areas. Frequently, these studies compared young individuals with older subjects, but few studies compared different age groups only in older populations. The purpose of this study is to analyze whole-brain functional connectivity in healthy older adult groups and its network characteristics through functional segregation. A total of 114 individuals, 48 to 89 years old, were scanned using resting-state functional magnetic resonance imaging in a resting state paradigm and were divided into six different age groups (< 60, 60-64, 65-69, 70-74, 75-79, ≥ 80 years old). A partial correlation analysis, a pooled correlation analysis and a study of 3-cycle regions with prominent connectivity were conducted. Our results showed progressive diminution in the functional connectivity among different age groups and this was particularly pronounced between 75 and 79 years old. The oldest group (≥ 80 years old) showed a slight increase in functional connectivity compared to the other groups. This occurred possibly because of compensatory mechanism in brain functioning. This study provides information on the brain functional characteristics of every age group, with more specific information on the functional progressive decline, and supplies methodological tools to study functional connectivity characteristics. Approval for the study was obtained from the ethics committee of the Comisión de Bioética de la Universidad de Barcelona (approval No. PSI2012-38257) on June 5, 2012, and from the ethics committee of the Barcelona's Hospital Clínic (approval No. 2009-5306 and 2011-6604) on October 22, 2009 and April 7, 2011 respectively.

Estimation of Brain Functional Connectivity in Patients with Mild Cognitive Impairment.

Mild cognitive impairment is defined as greater cognitive decline than expected for a person at a particular age and is sometimes considered a stage between healthy aging and Alzheimer's disease or other dementia syndromes. It is known that functional connectivity patterns change in people with this diagnosis. We studied functional connectivity patterns and functional segregation in a resting-state fMRI paradigm comparing 10 MCI patients and 10 healthy controls matched by education level, age and sex. Ninety ROIs from the automated anatomical labeling (AAL) atlas were selected for functional connectivity analysis. A correlation matrix was created for each group, and a third matrix with the correlation coefficient differences between the two matrices was created. Functional segregation was analyzed with the 3-cycle method, which is novel in studies of this topic. Finally, cluster analyses were also performed. Our results showed that the two correlation matrices were visually similar but had many differences related to different cognitive functions. Differences were especially apparent in the anterior default mode network (DMN), while the visual resting-state network (RSN) showed no differences between groups. Differences in connectivity patterns in the anterior DMN should be studied more extensively to fully understand its role in the differentiation of healthy aging and an MCI diagnosis.